This review is intended to stimulate interest in the effect of increased expression of heme oxygenase-1 (HO-1) protein and increased levels of HO activity on normal and pathological states. The HO system includes the heme catabolic pathway, comprising HO and biliverdin reductase, and the products of heme degradation, carbon monoxide (CO), iron, and biliverdin/bilirubin. The role of the HO system in diabetes, inflammation, heart disease, hypertension, neurological disorders, transplantation, endotoxemia and other pathologies is a burgeoning area of research. This review focuses on the clinical potential of increased levels of HO-1 protein and HO activity to ameliorate tissue injury. The use of pharmacological and genetic probes to manipulate HO, leading to new insights into the complex relationship of the HO system with biological and pathological phenomena under investigation, is reviewed. This information is critical in both drug development and the implementation of clinical approaches to moderate and to alleviate the numerous chronic disorders in humans affected by perturbations in the HO system.

Pharmacological and Clinical Aspects of Heme Oxygenase

Over twenty years of intensive work toward improvement of cisplatin, and with hundreds of platinum drugs tested, has resulted in the introduction of the widely used carboplatin and of oxaliplatin used only for a very narrow spectrum of cancers. A number of interesting platinum compounds including the orally administered platinum drug JM216, nedaplatin, the sterically hindered platinum(II) complex ZD0473, the trinuclear platinum complex BBR3464, and the liposomal forms Lipoplatin and SPI-77 are under clinical evaluation. This review summarizes the molecular mechanisms of platinum compounds for DNA damage, DNA repair and induction of apoptosis via activation or modulation of signaling pathways and explores the basis of platinum resistance. Cisplatin, carboplatin, oxaliplatin and most other platinum compounds induce damage to tumors via induction of apoptosis; this is mediated by activation of signal transduction leading to the death receptor mechanisms as well as mitochondrial pathways. Apoptosis is responsible for the characteristic nephrotoxicity, ototoxicity and most other toxicities of the drugs. The major limitation in the clinical applications of cisplatin has been the development of cisplatin resistance by tumors. Mechanisms explaining cisplatin resistance include the reduction in cisplatin accumulation inside cancer cells because of barriers across the cell membrane, the faster repair of cisplatin adducts, the modulation of apoptotic pathways in various cells, the upregulation in transcription factors, the loss of p53 and other protein functions and a higher concentration of glutathione and metallothioneins in some type of tumors. A number of experimental strategies to overcome cisplatin resistance are at the preclinical or clinical level such as introduction of the bax gene, inhibition of the JNK pathway, introduction of a functional p53 gene, treatment of tumors with aldose reductase inhibitors and others. Particularly important are combinations of platinum drug treatments with other drugs, radiation and the emerging gene therapy regimens.

https://www.spandidos-publications.com/10.3892/or.10.6.1663/download

Cisplatin and platinum drugs at the molecular level. (Review).

Cis- platin is an effective anti-neoplastic agent, but it is also highly nephrotoxic. Here, we clearly identify the human organic cation transporter 2 (hOCT2) as the critical transporter for cis- platin nephrotoxicity in isolated human proximal tubules and offer a potential mechanism for reducing nephrotoxicity in clinical practice. Interaction of cis- platin with hOCT2 in kidney or hOCT1 in liver was investigated with the fluorescent cation 4-[4-(dimethyl-amino)styril]-methylpyridinium in stably transfected HEK293 cells and for the first time in tissues physiologically expressing these transporters, human proximal tubules, and human hepatocyte couplets. Cis- platin (100 μmol/L) inhibited transport via hOCT2-HEK293 but not hOCT1-HEK293. In human proximal tubules cis- platin competed with basolateral organic cation transport, whereas it had no effect in tubules from a diabetic kidney or in hepatocytes. In hOCT2-HEK293 cells treated for 15 hours, incubation with cis- platin induced apoptosis, which was completely suppressed by contemporaneous incubation with the hOCT2 substrate cimetidine (100 μmol/L). These findings demonstrate that uptake of cis- platin is mediated by hOCT2 in renal proximal tubules, explaining its organ-specific toxicity. A combination of cis- platin with other substrates that compete for hOCT2 offers an effective option to decrease nephrotoxicity in the clinical setting.

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Cisplatin Nephrotoxicity Is Critically Mediated via the Human Organic Cation Transporter 2

Cisplatin is a platinum containing drug first approved as an antineoplastic agent in 1978. It remains an important and effective therapy in many forms of cancer today. Cisplatin mediates its tumorcidal effects via a number of different cytotoxic mechanisms. Although it is best known for DNA damage, cisplatin also causes cytoplasmic organelle dysfunction particularly with the endoplasmic reticulum and mitochondria. It also activates apoptotic pathways and inflicts cellular damage via oxidative stress and inflammation. One of its dose limiting toxicities is its effects on the kidney. This includes acute kidney injury as well as tubular injury resulting in electrolyte wasting. Extensive research has found that cisplatin entry into a cell is facilitated by a number of cellular transporters including human copper transport protein 1 (Ctr1) and the organic cation transporter 2 (OCT2) which are expressed on renal tubular cells. The interactions between the mechanisms of cytotoxicity and cellular transport play an important role in the nephrotoxicity. Better understanding of these interactions could one day help devise better renoprotection that would not reduce its anti-tumor effects.

Cisplatin nephrotoxicity: a review of the literature.

OBJECTIVE— We hypothesized that the induction of heme oxygenase (HO)-1 and increased HO activity, which induces arterial antioxidative enzymes and vasoprotection in a mouse and a rat model of diabetes, would ameliorate insulin resistance, obesity, and diabetes in the ob mouse model of type 2 diabetes.

RESEARCH DESIGN AND METHODS— Lean and ob mice were intraperitoneally administered the HO-1 inducer cobalt protoporphyrin (3 mg/kg CoPP) with and without the HO inhibitor stannous mesoporphyrin (2 mg/100 g SnMP) once a week for 6 weeks. Body weight, blood glucose, and serum cytokines and adiponectin were measured. Aorta, adipose tissue, bone marrow, and mesenchymal stem cells (MSCs) were isolated and assessed for HO expression and adipogenesis.

RESULTS— HO activity was reduced in ob mice compared with age-matched lean mice. Administration of CoPP caused a sustained increase in HO-1 protein, prevented weight gain, decreased visceral and subcutaneous fat content ( P < 0.03 and 0.01, respectively, compared with vehicle animals), increased serum adiponectin, and decreased plasma tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β levels ( P < 0.05). HO-1 induction improved insulin sensitivity and glucose tolerance and decreased insulin levels. Upregulation of HO-1 decreased adipogenesis in bone marrow in vivo and in cultured MSCs and increased adiponectin levels in the culture media. Inhibition of HO activity decreased adiponectin and increased secretion of TNF-α, IL-6, and IL-1β levels in ob mice.

CONCLUSIONS— This study provides strong evidence for the existence of an HO-1–adiponectin regulatory axis that can be manipulated to ameliorate the deleterious effects of obesity and the metabolic syndrome associated with cardiovascular disease and diabetes.

/pdf/treatment-of-obese-diabetic-mice-with-a-heme-oxygenase-51rjyi8fti.pdf

Treatment of Obese Diabetic Mice With a Heme Oxygenase Inducer Reduces Visceral and Subcutaneous Adiposity, Increases Adiponectin Levels, and Improves Insulin Sensitivity and Glucose Tolerance

SUMMARY:

Aim: Plasma adiponectin levels are well associated with metabolic syndrome. However, the relationship between hypertension and plasma adiponectin levels is not clear. Also, there is not enough data about the effects of different antihypertensive regimens on plasma adiponectin levels.



Methods:  Ninety-six hypertensive patients (48 male, 48 female) who fulfil the diagnostic criteria of metabolic syndrome were enrolled. Patients were treated for 3 months with metoprolol (n = 18, 100 mg/day), amlodipine (n = 20, 10 mg/day), doxazosin (n = 18, 4 mg/day), ramipril (n = 20, 5 mg/day) and valsartan (n = 20, 80 mg/day). Blood biochemistry and plasma adiponectin concentrations were measured both before and after the study. Insulin resistance was measured by homeostasis assessment index (HOMA).



Results:  Plasma adiponectin levels were correlated with the total cholesterol (r = −0.244, P = 0.017), triglyceride (r = −0.306, P = 0.002), high-density lipoprotein-cholesterol (r = 0.286, P = 0.005), body mass index (r = −374, P < 0.001), systolic (r = −502, P < 0.001) and diastolic blood pressures (r = −235, P = 0.021). The independent predictors of plasma adiponectin levels were HOMA (β = −0.199, P = 0.02), body mass index (β = −0.313, P < 0.001) and sytolic blood pressures (β = −0.483, P < 0.001). Ramipril and valsartan increased the plasma adiponectin levels significantly higher than the other regimens (P < 0.05 for both) while metoprolol did not make a significant effect.



Conclusion:  According to the results, plasma adiponectin levels are associated with the arterial blood pressures, body fat content and the lipid parameters in hypertensive patients with metabolic syndrome. The effects of antihypertensive drugs on plasma adiponectin levels are parallel to their effects on blood pressures and insulin sensitivities. The different effects of several regimens on plasma adiponectin levels and insulin sensitivities may account for the diversity of the cardiovascular outcomes in patients with hypertension.

Effect of antihypertensive agents on plasma adiponectin levels in hypertensive patients with metabolic syndrome.

Posttransplant symptomatic lymphocele treatment with percutaneous drainage and ethanol sclerosis Long-term follow-up

Background Nephrotoxicity is one of the most frequent dose-limiting factors of high-dose chemotherapy to create tolerance of autologous peripheral blood stem-cell transplantation (PBSCT) for the treatment of malignant diseases. The relative importance of factors that may be responsible for the development of nephrotoxicity varied in different trials. Methods The factors affecting nephrotoxicity in the early period of high-dose ifosfamide, carboplatin and etoposide treatment (ICE) followed by autologous PBSCT was investigated in 47 patients. ICE was given as a conditioning regimen for 6 days. Nephrotoxicity was defined as an increase in the serum creatinine concentration of 0.5 mg/dl or more over individual baseline levels. Results Eleven patients developed nephrotoxicity (23.4%). There was no significant difference in baseline renal function between patients with nephrotoxicity and those without. No differences were found between the two groups in terms of average total doses of ICE, infections and antibiotic use. The age of patients was higher in those with nephrotoxicity (37+/-3.7 vs 26+/-1.7 years, P=0.019). The cumulative cisplatin dose administered prior to this regimen was higher in the group that developed nephrotoxicity (470 vs 227 mg/m(2), P=0.02). The overall mortality rate was 17%, but the transplant-related deaths were higher in the presence of nephrotoxicity (54.5 vs 5.5%, P=0.001). Conclusions The cumulative dose of cisplatin is a strong risk factor for the development of nephrotoxicity in patients who receive high doses of ICE followed by PBSCT. Nephrotoxicity may occur with much lower doses than the currently recommended maximum doses.

/pdf/cumulative-prior-dose-of-cisplatin-as-a-cause-of-the-4m11noffh6.pdf

Cumulative prior dose of cisplatin as a cause of the nephrotoxicity of high‐dose chemotherapy followed by autologous stem‐cell transplantation

A case of a renal transplant recipient with colchicine-induced myopathy is presented. He was on colchicine therapy for 10 months. He was hospitalized for investigation of fatigue, severe myalgia in the lower extremities and elevated serum aminotransferase levels. His viral markers and other factors that may cause myalgia and that may increase the serum aminotransferase levels were either normal or negative. Creatine phosphokinase (CK) levels were normal. Electrophysiological findings indicated myopathy and muscle biopsy was consistent with vacuolar myopathy. After withdrawal of colchicine, the symptoms disappeared gradually and serum aminotransferase levels were normalized. We suggest that colchicine myopathy should be taken into account in patients who have been on colchicine therapy and had unexplained myalgia as well as elevated aminotransferase levels even with normal CK levels.

/pdf/colchicine-induced-myopathy-with-normal-creatine-2ev9zru38r.pdf

Colchicine-induced myopathy with normal creatine phosphokinase level in a renal transplant patient.

Sir, Patients undergoing chronic dialysis often believe they are unable to conceive, because of irregular menstruations and decreased libido; consequently, they do not regularly use contraceptive methods. Pregnancy is detected late, particularly in patients on peritoneal dialysis [1]. Early detection of pregnancy in dialysis patients is very important, in order to choose adequate methods for follow-up and treatment; late diagnosis increases the risk of maternal and foetal complications. We present a case of chronic haemodialysis, in which pregnancy was detected in the last trimester of pregnancy.

Izzet Yavuz

Papers

Effect of antihypertensive agents on plasma adiponectin levels in hypertensive patients with metabolic syndrome.

Posttransplant symptomatic lymphocele treatment with percutaneous drainage and ethanol sclerosis Long-term follow-up

Cumulative prior dose of cisplatin as a cause of the nephrotoxicity of high‐dose chemotherapy followed by autologous stem‐cell transplantation

Colchicine-induced myopathy with normal creatine phosphokinase level in a renal transplant patient.

Unexpected and late diagnosis (28th week) of pregnancy in a 39-year-old patient on chronic haemodialysis.