Showing papers in "Clinical Science in 2018"
TL;DR: The potential mechanisms underlying the association of inflammation and atherogenesis, and their clinical consequences are explored, with a view to harnessing inflammation to help target therapeutics, change guidelines, and enter daily practice.
Abstract: The concept that inflammation participates pivotally in the pathogenesis of atherosclerosis and its complications has gained considerable attention, but has not yet entered clinical practice. Experimental work has elucidated molecular and cellular pathways of inflammation that promote atherosclerosis. The recognition of atherogenesis as an active process rather than a cholesterol storage disease or a repository of calcium has highlighted some key inflammatory mechanisms. For example, mononuclear phagocytes contribute to all stages of this disease, illustrating the link between inflammation and atherosclerosis. From a clinical perspective, harnessing inflammation may now help target therapeutics, change guidelines, and enter daily practice. Multiple lines of incontrovertible evidence have proven a causal role for low-density lipoprotein (LDL) cholesterol in atherosclerosis, and we have highly effective tools for lowering LDL, consequently reducing events. Yet, even with intense LDL reduction, events still occur. Inflammation can explain some of this residual risk. An anti-inflammatory intervention has now proven capable of improving outcomes in individuals well treated with LDL-lowering agents. A suite of trials are now pursuing anti-inflammatory therapies in this context. Assessment and treatment of residual inflammatory risk are poised to provide new inroads into preventive cardiology. This brief review aims to explore the potential mechanisms underlying the association of inflammation and atherogenesis, and their clinical consequences.
468 citations
TL;DR: The hypotheses that high blood pressure patients have distinct gut microbiomes and that gut-epithelial barrier function markers and microbiome composition could predict systolic BP (SBP) were tested, supporting the conclusion that intestinal barrier dysfunction and microbiome function are linked to HTN in humans.
Abstract: Recent evidence indicates a link between gut pathology and microbiome with hypertension (HTN) in animal models. However, whether this association exists in humans is unknown. Thus, our objectives in the present study were to test the hypotheses that high blood pressure (BP) patients have distinct gut microbiomes and that gut-epithelial barrier function markers and microbiome composition could predict systolic BP (SBP). Fecal samples, analyzed by shotgun metagenomics, displayed taxonomic and functional changes, including altered butyrate production between patients with high BP and reference subjects. Significant increases in plasma of intestinal fatty acid binding protein (I-FABP), lipopolysaccharide (LPS), and augmented gut-targetting proinflammatory T helper 17 (Th17) cells in high BP patients demonstrated increased intestinal inflammation and permeability. Zonulin, a gut epithelial tight junction protein regulator, was markedly elevated, further supporting gut barrier dysfunction in high BP. Zonulin strongly correlated with SBP (R2 = 0.5301, P<0.0001). Two models predicting SBP were built using stepwise linear regression analysis of microbiome data and circulating markers of gut health, and validated in a separate cohort by prediction of SBP from zonulin in plasma (R2 = 0.4608, P<0.0001). The mouse model of HTN, chronic angiotensin II (Ang II) infusion, was used to confirm the effects of butyrate and gut barrier function on the cardiovascular system and BP. These results support our conclusion that intestinal barrier dysfunction and microbiome function are linked to HTN in humans. They suggest that manipulation of gut microbiome and its barrier functions could be the new therapeutic and diagnostic avenues for HTN.
299 citations
TL;DR: The gut microbiome is a major contributor to adverse cardiovascular outcomes and progression of CKD and the evidence supporting a role for gut-derived uremic toxins in promoting multiorgan dysfunction via inflammatory, oxidative stress, and apoptosis pathways is discussed.
Abstract: In chronic kidney disease (CKD), influx of urea and other retained toxins exerts a change in the gut microbiome. There is decreased number of beneficial bacteria that produce short-chain fatty acids, an essential nutrient for the colonic epithelium, concurrent with an increase in bacteria that produce uremic toxins such as indoxyl sulphate, p-cresyl sulphate, and trimethylamine-N-oxide (TMAO). Due to intestinal wall inflammation and degradation of intercellular tight junctions, gut-derived uremic toxins translocate into the bloodstream and exert systemic effects. In this review, we discuss the evidence supporting a role for gut-derived uremic toxins in promoting multiorgan dysfunction via inflammatory, oxidative stress, and apoptosis pathways. End-organ effects include vascular calcification, kidney fibrosis, anemia, impaired immune system, adipocyte dysfunction with insulin resistance, and low turnover bone disease. Higher blood levels of gut-derived uremic toxins are associated with increased cardiovascular events and mortality in the CKD population. Clinical trials that have examined interventions to trap toxic products or reverse gut microbial dysbiosis via oral activated charcoal AST-120, prebiotics and probiotics have not shown impact on cardiovascular or survival outcomes but were limited by sample size and short trials. In summary, the gut microbiome is a major contributor to adverse cardiovascular outcomes and progression of CKD.
127 citations
TL;DR: This review proposes how the blood pressure lowering and heart failure protective effect of SGLT2 inhibitors can be preserved in chronic kidney disease (CKD) despite attenuated antihyperglycemic effects and examines whether S GLT2 inhibition enhances the incidence or severity of acute kidney injury (AKI).
Abstract: Type 2 diabetes mellitus (T2DM) is a growing public health concern worldwide. Numerous drug classes are available for treatment, however, their efficacy with regard to diabetes-induced renal and cardiovascular (CV) complications remains limited. Inhibitors of the sodium-glucose cotransporter 2 (SGLT2) are a new class of blood glucose lowering medications that block renal glucose reabsorption and have protective effects on the kidney and the heart. This review focusses on the effects of SGLT2 inhibitors on the kidney and renal outcome: it briefly outlines renal glucose handling in diabetes and its role in glomerular hyperfiltration and renal hypoxia; describes how SGLT2 inhibitors induce an early, reversible reduction in glomerular filtration rate (GFR) and preserve GFR in the long-term in patients with T2DM; discusses whether the enhanced active transport in the renal outer medulla (OM) in response to SGLT2 inhibition is friend or foe; proposes how the blood pressure lowering and heart failure protective effect of SGLT2 inhibitors can be preserved in chronic kidney disease (CKD) despite attenuated antihyperglycemic effects; and examines whether SGLT2 inhibition enhances the incidence or severity of acute kidney injury (AKI).
116 citations
TL;DR: There is increasing evidence that ROS, inflammation and fibrosis promote each other and are part of a vicious connection leading to development and progression of CVD and kidney disease in diabetes.
Abstract: Chronic renal and vascular oxidative stress in association with an enhanced inflammatory burden are determinant processes in the development and progression of diabetic complications including cardiovascular disease (CVD), atherosclerosis and diabetic kidney disease (DKD). Persistent hyperglycaemia in diabetes mellitus increases the production of reactive oxygen species (ROS) and activates mediators of inflammation as well as suppresses antioxidant defence mechanisms ultimately contributing to oxidative stress which leads to vascular and renal injury in diabetes. Furthermore, there is increasing evidence that ROS, inflammation and fibrosis promote each other and are part of a vicious connection leading to development and progression of CVD and kidney disease in diabetes.
106 citations
TL;DR: Placental exosomes might have a role in the changes on insulin sensitivity in normal and GDM pregnancies, and the expression of these miRNAs varied in a consistent pattern in the placenta, in circulating exosome, and in skeletal muscle in GDM.
Abstract: There is increasing evidence that miRNAs, which are enriched in nanovesicles called exosomes, are important regulators of gene expression. When compared with normal pregnancies, pregnancies with gestational diabetes mellitus (GDM) are associated with skeletal muscle insulin resistance as well as increased levels of circulating placental exosomes. Here we investigated whether placental exosomes in GDM carry a specific set of miRNAs associated with skeletal muscle insulin sensitivity. Exosomes were isolated from chorionic villous (CV) explants from both women with Normal Glucose Tolerant (NGT) and GDM pregnancies. Using miRNA sequencing, we identified a specific set of miRNAs selectively enriched with exosomes and compared with their cells of origin indicating a specific packaging of miRNAs into exosomes. Gene target and ontology analysis of miRNA differentially expressed in exosomes secreted in GDM compared with NGT are associated with pathways regulating cell migration and carbohydrate metabolism. We determined the expression of a selected set of miRNAs in placenta, plasma, and skeletal muscle biopsies from NGT and GDM. Interestingly, the expression of these miRNAs varied in a consistent pattern in the placenta, in circulating exosomes, and in skeletal muscle in GDM. Placental exosomes from GDM pregnancies decreased insulin-stimulated migration and glucose uptake in primary skeletal muscle cells obtained from patients with normal insulin sensitivity. Interestingly, placental exosomes from NGT increase migration and glucose uptake in response to insulin in skeletal muscle from diabetic subjects. These findings suggest that placental exosomes might have a role in the changes on insulin sensitivity in normal and GDM pregnancies.
89 citations
TL;DR: In the present review, current knowledge concerning the involvement of NGAL in cardiovascular and renal diseases is summarized and the various mechanisms underlying its pathological implications are discussed.
Abstract: Neutrophil gelatinase-associated lipocalin (NGAL) is a small circulating protein that is highly modulated in a wide variety of pathological situations, making it a useful biomarker of various disease states. It is one of the best markers of acute kidney injury, as it is rapidly released after tubular damage. However, a growing body of evidence highlights an important role for NGAL beyond that of a biomarker of renal dysfunction. Indeed, numerous studies have demonstrated a role for NGAL in both cardiovascular and renal diseases. In the present review, we summarize current knowledge concerning the involvement of NGAL in cardiovascular and renal diseases and discuss the various mechanisms underlying its pathological implications.
84 citations
TL;DR: FG-4592 treatment remarkably ameliorated the cisplatin-induced kidney injury possibly through the stabilization of HIF, suggesting the clinical use of this novel HIF PHD inhibitor also could be extended to AKI.
Abstract: Renal hypoxia occurs in acute kidney injury (AKI) of various etiologies. Activation of hypoxia-inducible transcription factor (HIF) has been identified as an important mechanism of cellular adaptation to low oxygen. Preconditional HIF activation protects against AKI, suggesting a new approach in AKI treatment. HIF is degraded under normoxic conditions mediated by oxygen-dependent hydroxylation of specific prolyl residues of the regulative α-subunits by HIF prolyl hydroxylases (PHD). FG-4592 is a novel, orally active, small-molecule HIF PHD inhibitor for the treatment of anemia in patients with chronic kidney disease (CKD). The current study aimed to evaluate the effect of FG-4592 (Roxadustat) on cis-diamminedichloroplatinum (cisplatin)-induced kidney injury. In mice, pretreatment with FG-4592 markedly ameliorated cisplatin-induced kidney injury as shown by the improved renal function (blood urea nitrogen (BUN), serum creatinine (Scr), and cystatin C) and kidney morphology (periodic acid-Schiff (PAS) staining) in line with a robust blockade of renal tubular injury markers of kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL). Meanwhile, the renal apoptosis and inflammation induced by cisplatin were also strikingly attenuated in FG-4592-treated mice. Along with the protective effects shown above, FG-4592 pretreatment strongly enhanced HIF-1α in tubular cells, as well as the expressions of HIF target genes. FG-4592 alone did not affect the renal function and morphology in mice. In vitro, FG-4592 treatment significantly up-regulated HIF-1α and protected the tubular cells against cisplatin-induced apoptosis. In summary, FG-4592 treatment remarkably ameliorated the cisplatin-induced kidney injury possibly through the stabilization of HIF. Thus, besides the role in treating CKD anemia, the clinical use of FG-4592 also could be extended to AKI.
81 citations
TL;DR: This review addresses mechanisms and implications of circulating plasma thiol/disulphide redox pools, which are involved in several physiologic processes and explored as disease biomarkers, and highlights mechanisms whereby thiol pools affect atherosclerosis pathophysiology.
Abstract: Thiol groups are crucially involved in signaling/homeostasis through oxidation, reduction, and disulphide exchange. The overall thiol pool is the resultant of several individual pools of small compounds (e.g. cysteine), peptides (e.g. glutathione), and thiol proteins (e.g. thioredoxin (Trx)), which are not in equilibrium and present specific oxidized/reduced ratios. This review addresses mechanisms and implications of circulating plasma thiol/disulphide redox pools, which are involved in several physiologic processes and explored as disease biomarkers. Thiol pools are regulated by mechanisms linked to their intrinsic reactivity against oxidants, concentration of antioxidants, thiol-disulphide exchange rates, and their dynamic release/removal from plasma. Major thiol couples determining plasma redox potential (Eh) are reduced cysteine (CyS)/cystine (the disulphide form of cysteine) (CySS), followed by GSH/disulphide-oxidized glutathione (GSSG). Hydrogen peroxide and hypohalous acids are the main plasma oxidants, while water-soluble and lipid-soluble small molecules are the main antioxidants. The thiol proteome and thiol-oxidoreductases are emerging investigative areas given their specific disease-related responses (e.g. protein disulphide isomerases (PDIs) in thrombosis). Plasma cysteine and glutathione redox couples exhibit pro-oxidant changes directly correlated with ageing/age-related diseases. We further discuss changes in thiol-disulphide redox state in specific groups of diseases: cardiovascular, cancer, and neurodegenerative. These results indicate association with the disease states, although not yet clear-cut to yield specific biomarkers. We also highlight mechanisms whereby thiol pools affect atherosclerosis pathophysiology. Overall, it is unlikely that a single measurement provides global assessment of plasma oxidative stress. Rather, assessment of individual thiol pools and thiol-proteins specific to any given condition has more solid and logical perspective to yield novel relevant information on disease risk and prognosis.
79 citations
TL;DR: The current status of available mTOR inhibitors is summarized and the most relevant results from both preclinical and clinical studies that have provided valuable insights into both their efficacy and failure are highlighted.
Abstract: Mechanistic target of rapamycin (mTOR) is the kinase subunit of two structurally and functionally distinct large multiprotein complexes, referred to as mTOR complex 1 (mTORC1) and mTORC2. mTORC1 and mTORC2 play key physiological roles as they control anabolic and catabolic processes in response to external cues in a variety of tissues and organs. However, mTORC1 and mTORC2 activities are deregulated in widespread human diseases, including cancer. Cancer cells take advantage of mTOR oncogenic signaling to drive their proliferation, survival, metabolic transformation, and metastatic potential. Therefore, mTOR lends itself very well as a therapeutic target for innovative cancer treatment. mTOR was initially identified as the target of the antibiotic rapamycin that displayed remarkable antitumor activity in vitro . Promising preclinical studies using rapamycin and its derivatives (rapalogs) demonstrated efficacy in many human cancer types, hence supporting the launch of numerous clinical trials aimed to evaluate the real effectiveness of mTOR-targeted therapies. However, rapamycin and rapalogs have shown very limited activity in most clinical contexts, also when combined with other drugs. Thus, novel classes of mTOR inhibitors with a stronger antineoplastic potency have been developed. Nevertheless, emerging clinical data suggest that also these novel mTOR-targeting drugs may have a weak antitumor activity. Here, we summarize the current status of available mTOR inhibitors and highlight the most relevant results from both preclinical and clinical studies that have provided valuable insights into both their efficacy and failure.
73 citations
TL;DR: The ongoing Cardiovascular and Renal Microvascular Outcome Study with Linagliptin in Patients with Type 2 Diabetes Mellitus (CARMELINA®) study will definitively assess the renal effects of this DPP-4 inhibitor.
Abstract: Emerging evidence suggests that dipeptidyl peptidase-4 (DPP-4) inhibitors used to treat type 2 diabetes may have nephroprotective effects beyond the reduced renal risk conferred by glycemic control. DPP-4 is a ubiquitous protein with exopeptidase activity that exists in cell membrane-bound and soluble forms. The kidneys contain the highest levels of DPP-4, which is increased in diabetic nephropathy. DPP-4 inhibitors are a chemically heterogeneous class of drugs with important pharmacological differences. Of the globally marketed DPP-4 inhibitors, linagliptin is of particular interest for diabetic nephropathy as it is the only compound that is not predominantly excreted in the urine. Linagliptin is also the most potent DPP-4 inhibitor, has the highest affinity for this protein, and has the largest volume of distribution; these properties allow linagliptin to penetrate kidney tissue and tightly bind resident DPP-4. In animal models of kidney disease, linagliptin elicited multiple renoprotective effects, including reducing albuminuria, glomerulosclerosis, and tubulointerstitial fibrosis, independent of changes in glucagon-like peptide-1 (GLP-1) and glucose levels. At the molecular level, linagliptin prevented the pro-fibrotic endothelial-to-mesenchymal transition by disrupting the interaction between membrane-bound DPP-4 and integrin β1 that enhances signaling by transforming growth factor-β1 and vascular endothelial growth factor receptor-1. Linagliptin also increased stromal cell derived factor-1 levels, ameliorated endothelial dysfunction, and displayed unique antioxidant effects. Although the nephroprotective effects of linagliptin are yet to be translated to the clinical setting, the ongoing Cardiovascular and Renal Microvascular Outcome Study with Linagliptin in Patients with Type 2 Diabetes Mellitus (CARMELINA®) study will definitively assess the renal effects of this DPP-4 inhibitor. CARMELINA® is the only clinical trial of a DPP-4 inhibitor powered to evaluate kidney outcomes.
TL;DR: Autophagy was induced by diabetes possibly through ER stress-mediated JNK pathway, which may protect neurons against ER stress -associated cell damages, and suggest that ER stress pathway may be involved in diabetes-mediated neurotoxicity and promote the following cognitive impairments.
Abstract: Diabetes mellitus is a significant global public health problem depicting a rising prevalence worldwide. As a serious complication of diabetes, diabetes-associated cognitive decline is attracting increasing attention. However, the underlying mechanisms are yet to be fully determined. Both endoplasmic reticulum (ER) stress and autophagy have been reported to modulate neuronal survival and death and be associated with several neurodegenerative diseases. Here, a streptozotocin-induced diabetic mouse model and primary cultured mouse hippocampal neurons were employed to investigate the possible role of ER stress and autophagy in diabetes-induced neuronal apoptosis and cognitive impairments, and further explore the potential molecular mechanisms. ER stress markers GRP78 and CHOP were both enhanced in diabetic mice, as was phosphorylation of PERK, IRE1α, and JNK. In addition, the results indicated an elevated level of autophagy in diabetic mice, as demonstrated by up-regulated expressions of autophagy markers LC3-II, beclin 1 and down-regulated level of p62, and increased formation of autophagic vacuoles and LC3-II aggregates. Meanwhile, we found that these effects could be abolished by ER stress inhibitor 4-phenylbutyrate or JNK inhibitor SP600125 in vitro. Furthermore, neuronal apoptosis of diabetic mice was attenuated by pretreatment with 4-phenylbutyrate, while aggravated by application of inhibitor of autophagy bafilomycin A1 in vitro. These results suggest that ER stress pathway may be involved in diabetes-mediated neurotoxicity and promote the following cognitive impairments. More important, autophagy was induced by diabetes possibly through ER stress-mediated JNK pathway, which may protect neurons against ER stress-associated cell damages.
TL;DR: A growing body of preclinical and clinical evidence supports the theory that the gut microbiota and its metabolites have the potential to be a novel therapeutic and preventative target for cardiovascular and metabolic diseases.
Abstract: Accumulating evidence supports a relationship between the complexity and diversity of the gut microbiota and host diseases. In addition to alterations in the gut microbial composition, the metabolic potential of gut microbiota has been identified as a contributing factor in the development of diseases. Recent technological developments of molecular and biochemical analyses enable us to detect and characterize the gut microbiota via assessment and classification of its genomes and corresponding metabolites. These advances have provided emerging data supporting the role of gut microbiota in various physiological activities including host metabolism, neurological development, energy homeostasis, and immune regulation. Although few human studies have looked into the causative associations and underlying pathophysiology of the gut microbiota and host disease, a growing body of preclinical and clinical evidence supports the theory that the gut microbiota and its metabolites have the potential to be a novel therapeutic and preventative target for cardiovascular and metabolic diseases. In this review, we highlight the interplay between the gut microbiota and its metabolites, and the development and progression of hypertension, heart failure, and chronic kidney disease.
TL;DR: This work focuses on the pericyte modifications occurring in disease conditions, reviewing evidence supporting the interplay amongst pericytes, the endothelium, and glial cells in health and pathology.
Abstract: The cerebrovasculature is a multicellular structure with varying rheological and permeability properties The outer wall of the brain capillary endothelium is enclosed by pericytes and astrocyte end feet, anatomically assembled to guarantee barrier functions We, here, focus on the pericyte modifications occurring in disease conditions, reviewing evidence supporting the interplay amongst pericytes, the endothelium, and glial cells in health and pathology Deconstruction and reactivity of pericytes and glial cells around the capillary endothelium occur in response to traumatic brain injury, epilepsy, and neurodegenerative disorders, impacting vascular permeability and participating in neuroinflammation As this represents a growing field of research, addressing the multicellular reorganization occurring at the outer wall of the blood-brain barrier (BBB) in response to an acute insult or a chronic disease could disclose novel disease mechanisms and therapeutic targets
TL;DR: The authors focus on the current evidence describing the changes that occur in the intestinal microbiota with chronic alcohol consumption in conjunction with intestinal barrier breakdown and inflammatory changes sustaining the concept of a gut-liver-brain axis in the pathophysiology of alcohol dependence and alcoholic liver disease.
Abstract: Alcohol dependence and alcoholic liver disease represent a major public health problem with substantial morbidity and mortality. By yet incompletely understood mechanisms, chronic alcohol abuse is associated with increased intestinal permeability and alterations of the gut microbiota composition, allowing bacterial components, bacteria, and metabolites to reach the portal and the systemic circulation. These gut-derived bacterial products are recognized by immune cells circulating in the blood or residing in remote organs such as the liver leading to the release of pro-inflammatory cytokines which are considered important mediators of the liver-gut-brain communication. Although circulating cytokines are likely not the sole factors involved, they can induce liver inflammation/damage and reach the central nervous system where they favor neuroinflammation which is associated with change in mood, cognition, and drinking behavior. In this review, the authors focus on the current evidence describing the changes that occur in the intestinal microbiota with chronic alcohol consumption in conjunction with intestinal barrier breakdown and inflammatory changes sustaining the concept of a gut-liver-brain axis in the pathophysiology of alcohol dependence and alcoholic liver disease.
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TL;DR: This review outlines the key molecular pathways and cellular processes that underlie the phenotypic changes in the heart and vasculature that accompany aging and highlights the factors known to accelerate and attenuate the intrinsic aging of the heart.
Abstract: As the elderly segment of the world population increases, it is critical to understand the changes in cardiac structure and function during the normal aging process. In this review, we outline the key molecular pathways and cellular processes that underlie the phenotypic changes in the heart and vasculature that accompany aging. Reduced autophagy, increased mitochondrial oxidative stress, telomere attrition, altered signaling in insulin-like growth factor, growth differentiation factor 11, and 5'- AMP-activated protein kinase pathways are among the key molecular mechanisms underlying cardiac aging. Aging promotes structural and functional changes in the atria, ventricles, valves, myocardium, pericardium, the cardiac conduction system, and the vasculature. We highlight the factors known to accelerate and attenuate the intrinsic aging of the heart and vessels in addition to potential preventive and therapeutic avenues. A greater understanding of the processes involved in cardiac aging may facilitate our ability to mitigate the escalating burden of CVD in older individuals and promote healthy cardiac aging.
TL;DR: Findings about the molecular targets and mediators of glucocorticoid function are summarized.
Abstract: An established body of knowledge and clinical practice has argued in favor of the use of glucocorticoids in various chronic inflammatory and autoimmune diseases. However, the very well-known adverse effects associated with their treatment hampers continuation of therapy with glucocorticoids. Analyses of the molecular mechanisms underlying the actions of glucocorticoids have led to the discovery of several mediators that add complexity and diversity to the puzzling world of these hormones and anti-inflammatory drugs. Such mediators hold great promise as alternative pharmacologic tools to be used as anti-inflammatory drugs with the same properties as glucocorticoids, but avoiding their metabolic side effects. This review summarizes findings about the molecular targets and mediators of glucocorticoid function.
TL;DR: The various methodologies used to measure BAT metabolic activity in humans are discussed and critically evaluated to provide a contemporary assessment of protocols which may be useful in interpreting research findings and guiding the development of future studies.
Abstract: The activation of brown adipose tissue (BAT) is associated with reductions in circulating lipids and glucose in rodents and contributes to energy expenditure in humans indicating the potential therapeutic importance of targetting this tissue for the treatment of a variety of metabolic disorders. In order to evaluate the therapeutic potential of human BAT, a variety of methodologies for assessing the volume and metabolic activity of BAT are utilized. Cold exposure is often utilized to increase BAT activity but inconsistencies in the characteristics of the exposure protocols make it challenging to compare findings. The metabolic activity of BAT in response to cold exposure has most commonly been measured by static positron emission tomography of 18F-fluorodeoxyglucose in combination with computed tomography (18F-FDG PET-CT) imaging, but recent studies suggest that under some conditions this may not always reflect BAT thermogenic activity. Therefore, recent studies have used alternative positron emission tomography and computed tomography (PET-CT) imaging strategies and radiotracers that may offer important insights. In addition to PET-CT, there are numerous emerging techniques that may have utility for assessing BAT metabolic activity including magnetic resonance imaging (MRI), skin temperature measurements, near-infrared spectroscopy (NIRS) and contrast ultrasound (CU). In this review, we discuss and critically evaluate the various methodologies used to measure BAT metabolic activity in humans and provide a contemporary assessment of protocols which may be useful in interpreting research findings and guiding the development of future studies.
TL;DR: In this article, a mitochondrial fission inhibitor, Mdivi-1 (mitochondrial division inhibitor 1) (1.2 mg/kg) was used to attenuate arrhythmia, reduced infarct size, improved cardiac mitochondrial function and fragmentation, and decreased cardiac apoptosis.
Abstract: Altered cardiac mitochondrial dynamics with excessive fission is a predominant cause of cardiac dysfunction during ischemia/reperfusion (I/R) injury. Although pre-ischemic inhibition of mitochondrial fission has been shown to improve cardiac function in I/R injury, the effects of this inhibitor given at different time-points during cardiac I/R injury are unknown. Fifty male Wistar rats were subjected to sham and cardiac I/R injury. For cardiac I/R injury, rats were randomly divided into pre-ischemia, during-ischemia, and upon onset of reperfusion group. A mitochondrial fission inhibitor, Mdivi-1 (mitochondrial division inhibitor 1) (1.2 mg/kg) was used. During I/R protocols, the left ventricular (LV) function, arrhythmia score, and mortality rate were determined. Then, the heart was removed to determine infarct size, mitochondrial function, mitochondrial dynamics, and apoptosis. Our results showed that Mdivi-1 given prior to ischemia, exerted the highest level of cardioprotection quantitated through the attenuated incidence of arrhythmia, reduced infarct size, improved cardiac mitochondrial function and fragmentation, and decreased cardiac apoptosis, leading to preserved LV function during I/R injury. Mdivi-1 administered during ischemia and upon the onset of reperfusion also improved cardiac mitochondrial function and LV function, but at a lower efficacy than when it was given prior to ischemia. Taken together, mitochondrial fission inhibition after myocardial ischemic insults still exerts cardioprotection by attenuating mitochondrial dysfunction and dynamic imbalance, leading to decreased infarct size and ultimately improved LV function after acute cardiac I/R injury in rats. These findings indicate its potential clinical usefulness.
TL;DR: Hsa_circ_0012919 could be regarded as a biomarker for SLE and hsa-circ-012919 was the competitive endogenous RNA (ceRNA) for miR-125a-3p.
Abstract: Background: Systemic lupus erythematous (SLE) is an autoimmune disease characterized by production of autoantibodies directed against various autoantigens. But the expression profiles and functions of circRNAs in SLE are still scarce. Objectives: To explore the roles of circRNA in SLE and its potential diagnostic potential in SLE. Methods: SLE patients and healthy control subjects were recruited. CD4+ T cellswere isolated, circRNA microarray analysis were used to screen for circRNA candidate in CD4+ T cells. Expression of DNMT1, CD11a and CD70 and methylation level of CD11a and CD70 were detected after transfecting hsa_circ_0012919-targeted siRNA. The network analysis of hsa_circ_0012919 was used by bioinformatics. Luciferase reporter assay and FISH assay were used for screen for which miRNAs could bind with hsa_circ_0012919. Results: 12 circRNAs were upregulated and 2 circRNAs were downregulated in SLE patients group after circRNA microarray analysis. Hsa_circ_0012919 was further confirmed to be significantly different between healthy control and SLE patients (p
TL;DR: The mechanisms by which ASDN expressed channels are up-regulated by SGK1 are discussed, while newly discovered pathways connecting aldosterone to nonselective cation channels that are permeable to Mg2+ (TRPM7) or Ca2 + (TRPV4).
Abstract: Hyperaldosteronism, a common cause of hypertension, is strongly connected to Na+, K+, and Mg2+ dysregulation. Owing to its steroidal structure, aldosterone is an active transcriptional modifier when bound to the mineralocorticoid receptor (MR) in cells expressing the enzyme 11β-hydroxysteroid dehydrogenase 2, such as those comprising the aldosterone-sensitive distal nephron (ASDN). One such up-regulated protein, the ubiquitous serum and glucocorticoid regulated kinase 1 (SGK1), has the capacity to modulate the surface expression and function of many classes of renal ion channels, including those that transport Na+ (ENaC), K+ (ROMK/BK), Ca2+ (TRPV4/5/6), Mg2+ (TRPM7/6), and Cl- (ClC-K, CFTR). Here, we discuss the mechanisms by which ASDN expressed channels are up-regulated by SGK1, while highlighting newly discovered pathways connecting aldosterone to nonselective cation channels that are permeable to Mg2+ (TRPM7) or Ca2+ (TRPV4).
TL;DR: Evidence is provided that HDAC6 inhibition is protective against cisplatin-induced acute kidney injury (AKI) and suggest thatHDAC6 may be a potential therapeutic target for AKI treatment.
Abstract: Histone deacetylase 6 (HDAC6) has been shown to be involved in various pathological conditions, including cancer, neurodegenerative disorders and inflammatory diseases. Nonetheless, its specific role in drug-induced nephrotoxicity is poorly understood. Cisplatin (dichlorodiamino platinum) belongs to an inorganic platinum-fundamental chemotherapeutic drug utilized in the therapy of various solid malignant tumors. However, the use of cisplatin is limited by obvious side effects. In this study, we utilized a murine model of cisplatin-induced acute kidney injury (AKI) and a highly selective inhibitor of HDAC6, tubastatin A (TA), to assess the role of HDAC6 in nephrotoxicity and its associated mechanisms. Cisplatin-induced AKI was accompanied by increased expression and activation of HDAC6; blocking HDAC6 with TA lessened renal dysfunction, attenuated renal pathological changes, reduced expression of neutrophil gelatinase-associated lipocalin and Kim-1, and decreased tubular cell apoptosis. In cultured human epithelial cells, TA or HDAC6 siRNA treatment also inhibited cisplatin-induced apoptosis. Mechanistic studies demonstrated that cisplatin induced phosphorylation of AKT and loss of E-cadherin in the nephrotoxic kidney, and administration of TA enhanced AKT phosphorylation and preserved E-cadherin expression. HDAC6 inhibition also potentiated autophagy as evidenced by increased expression of Atg7, Beclin-1, and decreased renal oxidative stress as demonstrated by upregulation of superoxide dismutase activity and downregulation of malondialdehyde levels. Moreover, TA was effective in inhibiting NF-κB phosphorylation and suppressing the expression of tumor necrosis factor-a and interleukin-6. Collectively, these data provide strong evidence that HDAC6 inhibition is protective against cisplatin-induced AKI and suggest that HDAC6 may be a potential therapeutic target for AKI treatment.
TL;DR: The RAS is presented as a key mechanism of WAT and skeletal muscle metabolic dysfunction and the interaction between the RAS and exercise and the possible underlying mechanisms of the health-related aspects of ExT are discussed.
Abstract: Overactivation of the renin–angiotensin (Ang) system (RAS) increases the classical arm (Ang-converting enzyme (ACE)/Ang II/Ang type 1 receptor (AT1R)) to the detriment of the protective arm (ACE2/Ang 1-7/Mas receptor (MasR)). The components of the RAS are present locally in white adipose tissue (WAT) and skeletal muscle, which act co-operatively, through specific mediators, in response to pathophysiological changes. In WAT, up-regulation of the classical arm promotes lipogenesis and reduces lipolysis and adipogenesis, leading to adipocyte hypertrophy and lipid storage, which are related to insulin resistance and increased inflammation. In skeletal muscle, the classical arm promotes protein degradation and increases the inflammatory status and oxidative stress, leading to muscle wasting. Conversely, the protective arm plays a counter-regulatory role by opposing the effect of Ang II. The accumulation of adipose tissue and muscle mass loss is associated with a higher risk of morbidity and mortality, which could be related, in part, to overactivation of the RAS. On the other hand, exercise training (ExT) shifts the balance of the RAS towards the protective arm, promoting the inhibition of the classical arm in parallel with the stimulation of the protective arm. Thus, fat mobilization and maintenance of muscle mass and function are facilitated. However, the mechanisms underlying exercise-induced changes in the RAS remain unclear. In this review, we present the RAS as a key mechanism of WAT and skeletal muscle metabolic dysfunction. Furthermore, we discuss the interaction between the RAS and exercise and the possible underlying mechanisms of the health-related aspects of ExT.
TL;DR: The lncRNA-based combination index increased significantly after treatment and was correlated with neurological deficit severity of IS, indicating the ability of lncRNAs to monitor IS dynamics.
Abstract: Long noncoding RNAs (lncRNAs) have been highlighted to be involved in the pathological process of ischemic stroke (IS). The purpose of the present study was to investigate the expression profile of lncRNAs in peripheral blood mononuclear cells (PBMCs) of acute IS patients and to explore their utility as biomarkers of IS. Distinctive expression patterns of PBMC lncRNAs were identified by an lncRNA microarray and individual quantitative real-time PCR (qRT-PCR) in four independent sets for 206 IS, 179 healthy controls (HCs), and 55 patients with transient ischemic attack (TIA). A biomarker panel (lncRNA-based combination index) was established using logistic regression. LncRNA microarray analysis showed 70 up-regulated and 128 down-regulated lncRNAs in IS patients. Individual qRT-PCR validation demonstrated that three lncRNAs (linc-DHFRL1-4, SNHG15, and linc-FAM98A-3) were significantly up-regulated in IS patients compared with HCs and TIA patients. Longitudinal analysis of lncRNA expression up to 90 days after IS showed that linc-FAM98A-3 normalized to control levels by day 7, while SNHG15 remained increased, indicating the ability of lncRNAs to monitor IS dynamics. Receiver-operating characteristic (ROC) curve analysis showed that the lncRNA-based combination index outperformed serum brain-derived neurotrophic factor (BDNF) and neurone-specific enolase (NSE) in distinguishing IS patients from TIA patients and HCs with areas under ROC curve of more than 0.84. Furthermore, the combination index increased significantly after treatment and was correlated with neurological deficit severity of IS. The panel of these altered lncRNAs was associated with acute IS and could serve as a novel diagnostic method.
TL;DR: It is suggested that the anti-inflammatory effect of metformin relies on the control of additional pathways other than AMP-activated protein kinase, which is a good candidate for inhibiting pathological inflammation in the gut.
Abstract: Metformin, a hypoglycemic drug used for treatment of type 2 diabetes, regulates inflammatory pathways. By using several models of intestinal inflammation, we examined whether metformin exerts anti-inflammatory effects and investigated the basic mechanism by which metformin blocks pathologic signals. Colitic mice given metformin exhibited less colonic inflammation and increased expression of active AMP-activated protein kinase, a mediator of the metabolic effects of metformin, in both epithelial and lamina propria compartments. Pharmacological inhibition of AMP-activated protein kinase reduced but did not prevent metformin-induced therapeutic effect as well as treatment of colitic mice with a pharmacological activator of AMP-activated protein kinase attenuated but did not resolve colitis. These data suggest that the anti-inflammatory effect of metformin relies on the control of additional pathways other than AMP-activated protein kinase. Indeed, metformin down-regulated p38 MAP kinase activation in colitic mice through an AMP-activated protein kinase-independent mechanism. Expression of active form of AMP-activated protein kinase was reduced in inflammatory bowel disease patients and treatment of mucosal cells of such patients with metformin enhanced AMP-activated protein kinase activation and reduced p38 MAP kinase activation, thereby inhibiting interleukin-6 expression. Our findings indicate that metformin is a good candidate for inhibiting pathological inflammation in the gut.
TL;DR: Key mechanisms underlying the chronic inflammation seen in IBD as well as evidence implicating the intestinal microbiota in the development and potentiation of that inflammation are discussed.
Abstract: Inflammatory bowel diseases (IBD) are a group of chronic diseases of increasing worldwide prevalence characterized by gastrointestinal (GI) inflammation leading to debilitating symptoms and complications The contribution of the intestinal microbiota to the pathogenesis and etiology of these diseases is an area of active research interest Here, we discuss key mechanisms underlying the chronic inflammation seen in IBD as well as evidence implicating the intestinal microbiota in the development and potentiation of that inflammation We also discuss recently published work in areas of interest within the field of microbial involvement in IBD pathogenesis - the importance of proper microecology within the GI tract, the evidence that the intestinal microbiota transduces environmental and genetic risk factors for IBD, and the mechanisms by which microbial products contribute to communication between microbe and host There is an extensive body of published research on the evidence for microbial involvement in IBD; the goal of this review is to highlight the growing edges of the field where exciting and innovative research is pushing the boundaries of the conceptual framework of the role of the intestinal microbiota in IBD pathogenesis
TL;DR: It is observed that inhibition of autophagy by 3-methyladenine abolished uric acid-induced differentiation of renal fibroblasts to myofibroblast and activation of transforming growth factor-β1, epidermal growth factor receptor (EGFR), and Wnt signaling pathways in cultured renal interstitial fibro Blasts, indicating that hyperuricemia-induced autophages may represent a potential therapeutic strategy for HN.
Abstract: Autophagy has been identified as a cellular process of bulk degradation of cytoplasmic components and its persistent activation is critically involved in the renal damage induced by ureteral obstruction. However, the role and underlying mechanisms of autophagy in hyperuricemic nephropathy (HN) remain unknown. In the present study, we observed that inhibition of autophagy by 3-methyladenine (3-MA) abolished uric acid-induced differentiation of renal fibroblasts to myofibroblasts and activation of transforming growth factor-β1 (TGF-β1), epidermal growth factor receptor (EGFR), and Wnt signaling pathways in cultured renal interstitial fibroblasts. Treatment with 3-MA also abrogated the development of HN in vivo as evidenced by improving renal function, preserving renal tissue architecture, reducing the number of autophagic vacuoles, and decreasing microalbuminuria. Moreover, 3-MA was effective in attenuating renal deposition of extracellular matrix (ECM) proteins and expression of α-smooth muscle actin (α-SMA) and reducing renal epithelial cells arrested at the G2/M phase of cell cycle. Injury to the kidney resulted in increased expression of TGF-β1 and TGFβ receptor I, phosphorylation of Smad3 and TGF-β-activated kinase 1 (TAK1), and activation of multiple cell signaling pathways associated with renal fibrogenesis, including Wnt, Notch, EGFR, and nuclear factor-κB (NF-κB). 3-MA treatment remarkably inhibited all these responses. In addition, 3-MA effectively suppressed infiltration of macrophages and lymphocytes as well as release of multiple profibrogenic cytokines/chemokines in the injured kidney. Collectively, these findings indicate that hyperuricemia-induced autophagy is critically involved in the activation of renal fibroblasts and development of renal fibrosis and suggest that inhibition of autophagy may represent a potential therapeutic strategy for HN.
TL;DR: This work documented an enrichment of peripheral and intrahepatic HMGB1 signal in hepatitis B virus-related liver fibrosis progression, and presented a direct evidence of anatomic proximity ofHMGB1 with a-SMA (a marker for HSCs activation) in cirrhotic liver specimens, and demonstrated the autophagy-inducing effects by serum-sourced HMGB 1.
Abstract: High-mobility group box-1 (HMGB1) plays a context-dependent role in autophagy, which is required for hepatic stellate cells (HSCs) activation. However, the significance of HMGB1-induced HSCs autophagy in liver fibrosis has not been elucidated. Here, we first documented an enrichment of peripheral and intrahepatic HMGB1 signal in hepatitis B virus (HBV)-related liver fibrosis progression, and presented a direct evidence of anatomic proximity of HMGB1 with a-SMA (a marker for HSCs activation) in cirrhotic liver specimens. Then, we demonstrated the autophagy-inducing effects by serum-sourced HMGB1 in both primary murine HSCs and human HSCs cell line (LX-2), reflected by increased number of autophagic vacuoles (AVs) under the transmission electron microscope (TEM) and up-regulated protein expression of lipidated microtubule-associated light chain 3 (LC3-II) (a marker for autophagosome) in Western blot analysis. Intriguingly, there is a possible translocation of endogenous HMGB1 from the nucleus to cytoplasm to extracellular space, during exogenous HMGB1-induced HSCs autophagy. Meanwhile, the dose- and time-dependent effects by recombinant HMGB1 (rHMGB1) in enhancing LX-2 autophagy and fibrogenesis have been revealed with activated extracellular regulated protein kinase (ERK)/c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) and restrained mammalian target of rapamycin (mTOR)/STAT3 signaling pathways. Additionally, the ERK or JNK inhibitor could not only inhibit rHMGB1-induced autophagy and fibrogenesis in LX-2 cells, but also restore the suppressed mTOR and STAT3 pathways. Furthermore, using LC3-siRNA transfected LX-2, we found HMGB1-induced fibrogenesis is dependent on its autophagy-inducing effects. Finally, we elucidated the involvement of extracellular HMGB1-receptor for advenced glycation end product (RAGE) axis and endogenous HMGB1 in exogenous HMGB1-induced effects. Our findings could open new perspectives in developing an antifibrotic therapy by targetting the HSCs autophagy.
TL;DR: It is argued that CV benefit is specific to agents that provide longer acting agonism at the GLP-1 receptor, and the magnitude of CV protection is predominantly related to glucose-lowering.
Abstract: Type 2 diabetes (T2D) carries risks of both cardiovascular (CV) (myocardial infarction, stroke, and peripheral vascular disease) and microvascular (retinopathy/nephropathy/neuropathy) complications. Glucose-lowering is an effective strategy for preventing microvascular complications, but the extent to which it can reduce CV complications is less certain. Glucagon-like peptide-1 (GLP-1) agonists are potent glucose-lowering agents but also have potentially beneficial effects on other traditional (body weight, blood pressure (BP), and LDL cholesterol) and non-traditional risk factors (low grade inflammation and endothelial dysfunction). The results of four large CV outcome trials with GLP-1 agonists are now available. These have compared lixisenatide (ELIXA), liraglutide (LEADER), semaglutide (SUSTAIN-6), and long-acting exenatide (EXSCEL) with placebo and standard of care over 2-4 years; four others (including with dulaglutide and albiglutide) are ongoing. LEADER and SUSTAIN-6 have demonstrated reductions in rates of major adverse CV events with active GLP-1 treatment but ELIXA and EXSCEL have not. In this review, we discuss the mechanisms by which GLP-1 receptor agonists act on the CV system and the design and conduct of these trials. Contrary to the assertions that (a) all GLP-1 agonists reduce CV disease in T2D but to different extents or (b) the magnitude of CV protection is predominantly related to glucose-lowering, we argue that CV benefit is specific to agents that provide longer acting agonism at the GLP-1 receptor. The mechanisms involve reduction in body weight and BP, and lowering of LDL-cholesterol and glucose, but pleiotropic effects-including suppression of low grade inflammation, vasodilation, and natriuresis-are also likely relevant.
TL;DR: It is documented that TLR2 plays a protective role in cisplatin-induced AKI progression, in part, by a mechanism associated with autophagy up-regulation, considering that its interplay with HO-1 can promote renal tissue recover.
Abstract: Acute kidney injury (AKI) is considered an inflammatory disease in which toll-like receptors (TLRs) signaling pathways play an important role. The activation of TLRs results in production of several inflammatory cytokines leading to further renal damage. In contrast, TLRs are key players on autophagy induction, which is associated with a protective function on cisplatin-induced AKI. Hence, the present study aimed to evaluate the specific participation of TLR2 and TLR4 molecules on the development of cisplatin-induced AKI. Complementarily, we also investigated the link between TLRs and heme oxygenase-1 (HO-1), a promisor cytoprotective molecule. First, we observed that only the absence of TLR2 but not TLR4 in mice exacerbated the renal dysfunction, tissue injury and mortality rate, even under an immunologically privileged microenvironment. Second, we demonstrated that TLR2 knockout (KO) mice presented lower expression of autophagy-associated markers when compared with TLR4 KO animals. Similar parameter was confirmed in vitro, using tubular epithelial cells derived from both KO mice. To test the cross-talking between HO-1 and TLRs, hemin (an HO-1 internal inducer) was administrated in cisplatin-treated TLR2 and TLR4 KO mice and it was detected an improvement in the global renal tissue parameters. However, this protection was less evident at TLR2 KO mice. In summary, we documented that TLR2 plays a protective role in cisplatin-induced AKI progression, in part, by a mechanism associated with autophagy up-regulation, considering that its interplay with HO-1 can promote renal tissue recover.