Showing papers by "Andrew M. Hall published in 2019"

The Obese Liver Environment Mediates Conversion of NK Cells to a Less Cytotoxic ILC1-Like Phenotype.

Abstract: The liver contains both NK cells and their less cytotoxic relatives, ILC1. Here, we investigate the role of NK cells and ILC1 in the obesity-associated condition, non-alcoholic fatty liver disease (NAFLD). In the livers of mice suffering from NAFLD, NK cells are less able to degranulate, express lower levels of perforin and are less able to kill cancerous target cells than those from healthy animals. This is associated with a decreased ability to kill cancer cells in vivo. On the other hand, we find that perforin-deficient mice suffer from less severe NAFLD, suggesting that this reduction in NK cell cytotoxicity may be protective in the obese liver, albeit at the cost of increased susceptibility to cancer. The decrease in cytotoxicity is associated with a shift toward a transcriptional profile characteristic of ILC1, increased expression of the ILC1-associated proteins CD200R1 and CD49a, and an altered metabolic profile mimicking that of ILC1. We show that the conversion of NK cells to this less cytotoxic phenotype is at least partially mediated by TGFβ, which is expressed at high levels in the obese liver. Finally, we show that reduced cytotoxicity is also a feature of NK cells in the livers of human NAFLD patients.

Collagen proportionate area is an independent predictor of long-term outcome in patients with non-alcoholic fatty liver disease.

Abstract: Background Collagen proportionate area (CPA) measurement is a technique that quantifies fibrous tissue in liver biopsies by measuring the amount of collagen deposition as a proportion of the total biopsy area. CPA predicts clinical outcomes in patients with HCV and can sub-classify cirrhosis. Aim To test the ability of CPA to quantify fibrosis and predict clinical outcomes in patients with NAFLD. Methods We assessed consecutive patients with biopsy-proven NAFLD from three European centres. Clinical and laboratory data were collected at baseline and at the time of the last clinical follow-up or death. CPA was performed at two different objective magnifications, whole biopsy macro and ×4 objective magnification, named standard (SM) and high (HM) magnification respectively. The correlation between CPA and liver stiffness was assessed in a sub-group of patients. Results Of 437 patients, 32 (7.3%) decompensated and/or died from liver-related causes during a median follow-up of 103 months. CPA correlated with liver stiffness and liver fibrosis stage across the whole spectrum of fibrosis. HM CPA was significantly higher than SM CPA in stages F0-F3 but similar in cirrhosis, reflecting a higher ability to capture pericellular/perisinusoidal fibrosis at early stages. Age at baseline (HR: 1.04, 95% CI: 1.01-1.08), HM CPA (HR: 1.04 per 1% increase, 95% CI: 1.01-1.08) and presence of advanced fibrosis (HR: 15.4, 95% CI: 5.02-47.84) were independent predictors of liver-related clinical outcomes at standard and competing risk multivariate Cox-regression analysis. Conclusions CPA accurately measures fibrosis and is an independent predictor of clinical outcomes in NAFLD; hence it merits further evaluation as a surrogate endpoint in clinical trials.

Overcoming Endocytosis Deficiency by Cubosome Nanocarriers

Abstract: The use of lipid-based nanoparticles for the delivery of biomacromolecules has attracted considerable attention due to the current interest in protein-based therapeutics. Cubosomes protect the incorporated therapeutics, which are susceptible to degradation by enzymes, thereby improving their bioavailability, and concomitantly enhance cellular uptake. The cubosome nanoparticles presented herein were loaded with bovine serum albumin (BSA) and characterized by small-angle X-ray scattering and dynamic light scattering techniques, while the BSA encapsulation and its release were evaluated in vitro. The ability of this formulation to increase the cellular uptake of albumin by 2-fold was tested on various types of renal tubular cells and confirmed by in vivo renal uptake experiments in mice. The obtained results show that cubosomes are able to deliver BSA inside the cell through distinct uptake and intracellular routing. These data were substantiated, with evidence of a high cubosome-mediated uptake of BSA in Clcn5 knockout mice characterized by defective receptor-mediated endocytosis. The use of cubosomes as a delivery system thus represents a promising approach to overcome the low endocytic uptake in diseased epithelial cells and to treat dysfunctions of the kidney proximal tubule.

Etiology and severity of liver disease in HIV-positive patients with suspected NAFLD : lessons from a cohort with available liver biopsies

Abstract: Background Spectrum of liver injury among HIV-positive people is wide; in particular, prevalence of nonalcoholic fatty liver disease (NAFLD) seems to be higher compared with HIV-negative people. Methods We retrospectively evaluated all liver biopsies performed at Royal Free Hospital from 2000 to 2017 in HIV monoinfected patients with abnormal transaminases, to assess the underlying cause of liver disease and to characterize the extent of fibrosis. We furthermore evaluated the diagnostic accuracy of FIB4 and FibroScan as noninvasive tools for fibrosis assessment. Results Ninety-seven patients were included. Most common histological findings were NAFLD (28%), nonspecific changes (26%), and normal histology (13%). Twenty percent of the patients had significant fibrosis and 11% had advanced fibrosis. FIB4, at a cutoff of 1.3, had a specificity of 82% and negative predictive value (NPV) of 95% for exclusion of advanced fibrosis. FibroScan was available in 28% patients and 33% had a liver stiffness ≥7.5 kPa. FibroScan showed a specificity of 77% and NPV of 94% for exclusion of significant fibrosis. Among patients with NAFLD (n = 27), 18% had advanced fibrosis, whereas the majority (56%) did not have any fibrosis. The NPV of FIB4 for advanced fibrosis in these patients was 93%. Conclusions Among HIV-positive patients with elevated transaminases, a surprisingly high number of patients had nonsignificant changes or even normal histological findings. The prevalence of NAFLD was lower than reported in other series. Use of noninvasive tools with a high NPV for significant fibrosis can help reduce the number of required biopsies.

Decellularized Human Gut as a Natural 3D Platform for Research in Intestinal Fibrosis

Abstract: Background The current methodologies for the identification of therapeutic targets for inflammatory bowel disease (IBD) are limited to conventional 2-dimensional (2D) cell cultures and animal models. The use of 3D decellularized human intestinal scaffolds obtained from surgically resected intestine and engineered with human intestinal cells may provide a major advancement in the development of innovative intestinal disease models. The aim of the present study was to design and validate a decellularization protocol for the production of acellular 3D extracellular matrix (ECM) scaffolds from the human duodenum. Methods Scaffolds were characterized by verifying the preservation of the ECM protein composition and 3D architecture of the native intestine and were employed for tissue engineering with primary human intestinal myofibroblasts for up to 14 days. Results Engrafted cells showed the ability to grow and remodel the surrounding ECM. mRNA expression of key genes involved in ECM turnover was significantly different when comparing primary human intestinal myofibroblasts cultured in 3D scaffolds with those cultured in standard 2D cultures on plastic dishes. Moreover, incubation with key profibrogenic growth factors such as TGFβ1 and PDGF-BB resulted in markedly different effects in standard 2D vs 3D cultures, further emphasizing the importance of using 3D cell cultures. Conclusions These results confirm the feasibility of 3D culture of human intestinal myofibroblasts in intestinal ECM scaffolds as an innovative platform for disease modeling, biomarker discovery, and drug testing in intestinal fibrosis.

Axial differences in endocytosis along the kidney proximal tubule.

Abstract: The proximal tubule (PT) reabsorbs filtered proteins via receptor-mediated endocytosis to prevent energetically inefficient wasting in the urine. Recent intravital imaging studies have suggested th...

Targeting glycolysis in proliferative kidney diseases

Abstract: Glycolytic activity is increased in proliferating cells, leading to the concept that glycolysis could be a therapeutic target in cystic diseases and kidney cancer. Preclinical studies using the glucose analog 2-deoxy-d-glucose have shown promise; however, inhibiting glycolysis in humans is unlikely to be without risks. While proximal tubules are predominantly aerobic, later segments are more glycolytic. Understanding exactly where and why glycolysis is important in the physiology of the distal nephron is thus crucial in predicting potential adverse effects of glycolysis inhibitors. Live imaging techniques could play an important role in the process of characterizing cellular metabolism in the functioning kidney. The goal of this review is to briefly summarize recent findings on targeting glycolysis in proliferative kidney diseases and to highlight the necessity for future research focusing on glycolysis in the healthy kidney.

A Case of Drug-Induced Proximal Tubular Dysfunction

Abstract: The kidney proximal tubule is the first part of the nephron after the filtering glomerulus and performs the bulk of reabsorption of filtered solutes. Proximal tubular cells are highly adapted to this task and express numerous sodium-coupled transporters. They also express two large receptors called

The obese liver environment mediates conversion of NK cells to a less cytotoxic ILC1-like phenotype

Abstract: Non-alcoholic fatty liver disease (NAFLD) is an obesity-associated disease in which the fatty liver becomes chronically inflamed. Here, we report that in the livers of both humans and mice suffering from NAFLD, NK cells are less able to degranulate. In mice, this is associated with a decreased ability to kill cancerous targets both in vitro and in vivo. On the other hand, perforin-deficient mice suffer from less severe NAFLD, suggesting that perforin-mediated killing is harmful in the obese liver and that the reduction in NK cell cytotoxicity may therefore be protective. The decrease in cytotoxicity is associated with a shift towards a transcriptional profile characteristic of ILC1, increased expression of inhibitory receptors expressed by ILC1, and an altered metabolic profile mimicking that of ILC1. This conversion of NK cells to a less cytotoxic ILC1-like phenotype is at least partially mediated by high levels of TGF{beta} produced in the obese liver.