Sedat Ustundag

Experimental Myoglobinuric Acute Renal Failure: The Effect of Vitamin C

During times of war and natural disasters, rhabdomyolysis-induced myoglobinuric acute renal failure (ARF) can assume epidemic proportions. Free radicals play an important role in the pathogenesis of myoglobinuric ARF. Vitamin C is a major antioxidant, scavenging free radicals. We have not found any studies on the effect of vitamin C on myoglobinuric ARF. Thus, we aimed to investigate the effects of vitamin C on the myoglobinuric ARF formed by glycerol in rats. Three groups of rats were employed in this study. Group 1 served as control, group 2 was given 50% glycerol (10 mL/kg, i.m.), and group 3 was given glycerol plus vitamin C (20 mg/kg, i.p. for four days). Ninety-six hours after glycerol injections, blood samples and kidney tissues were taken from the anesthetized rats. Urea and creatinine levels in plasma; N-acetyl-beta-D-glucosaminidase activity in urine; malondialdehyde levels, superoxide dismutase and catalase enzyme activity in kidney tissue were determined. Histopathological changes and iron accumulation in the kidney tissue were evaluated. In this study, glycerol administration led to marked renal oxidative stress and severe renal functional and morphological deterioration. The treatment of animals with vitamin C partially corrected the renal dysfunction and morphological impairment. In this respect, vitamin C appears to be a promising candidate for the prevention of rhabdomyolysis-induced ARF. Higher dosages of vitamin C than in 20 mg/kg may be beneficial for better functional and morphological recovery in this model ARF.

Glu298Asp polymorphism of the endothelial nitric oxide synthase gene in Turkish patients with ischemic stroke

The low plasma nitric oxide concentrations and reduced vascular reactivity are considered major proatherogenic mechanisms in cardiovascular diseases. The present study aimed to assess the allelic frequency and the genotypic distribution of the Glu298Asp gene polymorphism at exon 7 of endothelial nitric oxide synthase (eNOS) gene in Turkish ischemic stroke patients compared to appropriate healthy controls, and to correlate the genetic findings with stroke subtypes. The study population included 146 (75 males, 71 females) patients with ischemic stroke which were categorized according to the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) and 133 (34 males, 99 females) healthy subjects. The eNOS polymorphism was identified with a PCR followed by RFLP with the restriction enzyme BanII. Genotypes were defined as GG, GT, and TT according to the presence of the G and T alleles. In this case-control study, we did not find any significant difference in either the genotypic distribution or allelic frequency of Glu298Asp gene polymorphism between the patients and the controls. In addition, there was also no significant difference for the genotype distribution and the allelic frequency among the stroke subtypes. The results suggested the lack of the association between the Glu298Asp gene polymorphism and ischemic stroke or subtypes of ischemic stroke in the Turkish population.

L-Carnitine ameliorates glycerol-induced myoglobinuric acute renal failure in rats.

There is increasing evidence indicating that oxidative stress plays an important role in the pathogenesis of rhabdomyolysis-induced myoglobinuric acute renal failure (ARF). During times of war and natural disasters, myoglobinuric ARF can assume epidemic proportions. Thus, early and effective renoprotective treatments are of utmost importance. It has been shown that L-carnitine, used as a safe and effective nutritional supplement for more than three decades, is effective in preventing renal injury in many renal injury models involving oxidative stress. The present study was performed to investigate the effects of L-carnitine in an experimental model of myoglobinuric ARF. Four groups of rats were employed in this study: group 1 served as a control; group 2 was given glycerol (10 mL/kg, i.m.); group 3 was given glycerol plus L-carnitine (100 mg/kg, i.p.), starting at the same time as the glycerol injection; group 4 was given glycerol plus L-carnitine (100 mg/kg, i.p.), starting 48h before the glycerol injection. After glycerol injections, the i.p. injections of L-carnitine were repeated every 24h for four days. Ninety-six hours after glycerol injections, blood samples and kidney tissues were taken from the anesthetized rats. Urea and creatinine levels in plasma, N-acetyl-beta-D-glucosaminidase activity in urine, and malondialdehyde levels and catalase enzyme activity in kidney tissue were determined. Histopathological changes and iron accumulation in the kidney tissue were evaluated. In this study, glycerol administration led to marked renal oxidative stress, as well as severe functional and morphological renal deterioration. L-carnitine, possibly via its antioxidant properties, ameliorates glycerol-induced myoglobinuric kidney injury.

Protective effects of irbesartan and alpha lipoic acid in STZ-induced diabetic nephropathy in rats

The aim of this study was designed to investigate the possible beneficial effects of the angiotensin (ang) II T1 (AT1) receptor blocker, irbesartan (Irb), and the alpha lipoic acid (ALA) in streptozotocin (STZ)-induced diabetic nephropathy (DNP) in rats. The rats were randomly allotted into one of five experimental groups: A, control; B, diabetic untreated; C, diabetic treated with Irb; D, diabetic treated with ALA; and E, diabetic treated with Irb + ALA; each group contains 10 animals. B, C, D, and E groups received STZ. Diabetes was induced in four groups by a single intraperitoneal injection of STZ (50 mg/kg, freshly dissolved in 5 mmol/L citrate buffer, pH 4.5). The rats in Irb-, ALA-, and Irb + ALA-treated groups were given Irb (5 mg/kg), ALA (in a dose of 3 mg/kg), and Irb + ALA (in a dose of 2.5 + 1.5 mg/kg) once a day orally by using intragastric intubation for 12 weeks starting 2 days after STZ injection, respectively. Treatment with ALA and especially Irb reduced the glomerular size; thickening of capsular, glomerular, and tubular basement membranes; increased amounts of mesangial matrix and tubular dilatation as compared with diabetic-untreated rats. Notably, the better effects were obtained when Irb and ALA were given together. We conclude that Irb, ALA, and especially Irb + ALA therapy causes renal morphologic improvement after STZ-induced diabetes in rats. We believe that further preclinical research into the utility of Irb and ALA treatment, alone or its combination, may indicate its usefulness as a potential treatment in DNP.

Effect of Angiotensin-Converting Enzyme Inhibition and Angiotensin II Type 1 Receptor Blockade on Streptozotocin-Induced Diabetic Nephropathy

The aim of this study was designed to investigate the possible beneficial effects of the angiotensin-converting enzyme (ACE) inhibitor, Quinapril (Q) and, the angiotensin (ang) II T1 (AT1) receptor blocker, irbesartan (Irb), in streptozotocin (STZ)-induced diabetes in rats. The rats were randomly allotted into one of five experimental groups: A (control), B (diabetic untreated), C (diabetic treated with Q), D (diabetic treated with Irb), and E (diabetic treated with Q&Irb), each group containing 10 animals. Groups B–E received STZ. Diabetes was induced in four groups by a single intraperitoneal (i.p) injection of STZ (50 mg/kg, freshly dissolved in 5 mmol/L citrate buffer, pH 4.5). Two days after STZ treatment, development of diabetes in four experimental groups was confirmed by measuring blood glucose levels in a tail vein blood samples. Rats with blood glucose levels of 250 mg/dL or higher were considered to be diabetic. The rats in Q-, Irb-, and Q&Irb-treated groups were given Q (in a dose of 3 mg/kg body weight), Irb (5 mg/kg body weight), and Q&Irb (in a dose of 1.5 mg/kg + 2.5 mg/kg body weight) once a day orally by using intra-gastric intubation for 12 weeks starting two days after STZ injection. Treatment of Q and especially Irb reduced the glomerular size and thickening of capsular, glomerular, and tubular basement membranes; and increased amounts of mesangial matrix and tubular dilatation and renal function as compared with diabetics untreated. Notably, the better effects were obtained when Q and Irb given together. We conclude that Q, Irb, and especially Q+Irb therapy causes renal morphologic and functional improvement after STZ-induced diabetes in rats. We believe that further preclinical research into the utility of Q and Irb treatment, alone or its combination, may indicate its usefulness as a potential treatment in diabetic nephropathy (DNp).

The relationship between mean platelet volume and neutrophil/lymphocyte ratio with inflammation and proteinuria in chronic kidney disease

Atherosclerosis, which develops as a result of inflammation, is the most important cause of morbidity and mortality in chronic kidney disease (CKD). In this study, we investigated the relationship of mean platelet volume (MPV) and neutrophil/lymphocyte ratio (NLR) with inflammation and proteinuria in patients with CKD Stage 3-4. Healthy individuals who applied to nephrology clinic for checkup purposes acted as controls. Fifty-three patients and 30 healthy controls were included in the study. Patients with diabetes mellitus, active infection, malignancy, and coronary artery disease were excluded from the study. Biochemistry values and hemograms were recorded for all patients and for control group. NLR was calculated. The relationship between MPV/NLR and protein, fibrinogen, and proteinuria was evaluated. Our study showed a statistically significant difference between CKD group and healthy control (HC) group in uric acid, fibrinogen, C-reactive protein, and NLR values (P <0.01, P <0.01, P = 0.01, P <0.01, respectively). No statistically significant difference was found between CKD and HC groups for MPV (P = 0.307). Correlation analysis revealed a statistically significant relationship between NLR and creatinine (P <0.00, r = 0.571), uric acid (P <0.00, r = 0.436), glomerular filtration rate (P <0.00, r = -0.418), 24 h urine protein (P = 0.004, r = 0.311), and 24 h urine microalbumin (P = 0.001, r = 0.354). A statistically significant relationship was detected between MPV and platelet count (P <0.001, r = -0.422), age (P = 0.004, r = -0.312), uric acid (P = 0.04, r = -0.226), and fibrinogen (P = 0.023, r = -0.249). Whereas, a statistically significant relationship was detected between NLR and microalbuminuria/proteinuria, there was no statistically significant relationship between MPV and microalbuminuria/proteinuria. Our study showed that the NLR is high in CKD group and is correlated with uric acid and proteinuria, which are known to be associated with atherosclerosis, in patients with CKD. NLR may be a determinant of inflammation and atherosclerosis in patients with CKD.

Carotid intima media thickness is independently associated with urinary sodium excretion in patients with chronic kidney disease

Abstract Atherosclerosis-induced premature vascular diseases are the leading cause of mortality among patients with chronic kidney disease (CKD). The pathogenetic mechanism of atherosclerosis in patients with CKD has not been fully explained. Experimental studies have demonstrated that high dietary sodium intake not only increases circulatory volume and blood pressure, but also facilitates development of atherosclerosis by reducing production-bioavailability of nitric oxide due to oxidative stress and accordingly by enhancing endothelial and arterial stiffness. In this study, we investigated the relationship between sodium consumption and carotid artery intima-media thickness, which is the indicator of atherosclerosis, by determining daily urinary sodium excretion, which is a reliable indicator of sodium consumption, in our patient group. Our patient group included 193 patients with stage 2–4 non-diabetic CKD and without a history of atherosclerotic disease. We determined that 77% of our patients have been consuming more than 2  g of sodium per day, which is the upper limit of sodium consumption recommended for patients with CKD. We determined a positive linear correlation between carotid artery intima-media thickness and patient age (p < 0.001), C-reactive protein (p < 0.001), urinary sodium excretion (p < 0.001), body mass index (p = 0.002), systolic blood pressure (p = 0.002), hemoglobin (p = 0.030), triglycerides (p = 0.043), and diastolic blood pressure (p = 0.049). We also found a negative linear correlation between carotid artery intima-media thickness and glomerular filtration rate (p = 0.008). We found that urinary sodium excretion is the determinant of intima-media thickness even if all factors associated with intima-media thickness are adjusted, and that intima-media thickness increases by 0.031 (0.004–0.059) mm per 2  g increase in daily sodium excretion, independent from overall factors (p = 0.025). Our results reveal a relation between urinary sodium excretion and carotid artery intima-media thickness and suggest that excessive sodium consumption predisposes development of atherosclerosis in patients with CKD.

Once-monthly continuous erythropoietin receptor activator (CERA) for haemoglobin maintenance in haemodialysis patients with chronic renal anaemia

Background This study was conducted to evaluate the efficacy and safety of once-monthly continuous erythropoietin receptor activator (CERA) for maintenance of stable haemoglobin (Hb) levels in adult chronic renal anaemia patients on dialysis according to local clinical judgment in Turkey. Methods This was a prospective, open-label, single-arm, multi-centre study conducted in 20 centres in Turkey. After a 4-week screening period, eligible patients receiving conventional erythropoiesis-stimulating agents were converted to monthly intravenous CERA and entered a 16-week CERA dose-titration period (DTP) followed by an 8-week efficacy evaluation period (EEP) and a 4-week safety follow-up. The primary endpoint was the proportion of patients whose Hb concentration remained stable within ±1.0 g/dL of their reference Hb and within the range of 10.0–12.0 g/dL during the EEP. Results A total of 173 patients were screened, 132 entered the DTP and 84 completed the study. Thirty-nine patients [46.4% (95% confidence interval: 35.5–57.7%)] maintained stable target Hb concentrations. The mean change in time-adjusted average Hb concentration was 0.29 ± 1.08 g/dL between baseline and the EEP. The mean CERA monthly dose was 112.4 ± 76.78 µg during the EEP, and the CERA dose was adjusted in 39 patients (36.4%). Eleven patients (8.4%) reported 13 treatment-related adverse events, the most frequent adverse events being infections and infestations, gastrointestinal and vascular disorders. Conclusions Once-monthly CERA maintains stable Hb concentrations in chronic renal anaemia patients on dialysis in Turkey. The study results confirm the known efficacy and safety profile of CERA.

Investigation of the relationship between MTHFR, IRS and CALCA gene polymorphisms and development of diabetic nephropathy in patients with type 2 diabetes mellitus

ABSTRACT The aim of this study was to investigate the relationship between MTHFR, IRS and CALCA gene polymorphisms and development of diabetic nephropathy (DN) in patients with type 2 diabetes mellitus (DM). Our study included 93 patients with type 2 DM diagnosed as having nephropathy and 95 controls diagnosed with type 2 DM without development of DN. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were used to determine the genotype distributions of MTHFR, IRS and CALCA gene polymorphisms. The results showed no statistically significant difference between DN patients and type 2 DM controls in terms of genotype distributions of MTHFR (C677T, A1298C), IRS (IRS-1 Gly972Arg, IRS-2 Gly1057Asp) and CALCA T692C gene polymorphisms (p > 0.05). However, in terms of allele frequencies for the MTHFR A1298C gene, the frequency of the C allele was significantly higher in the DN patients compared to the controls (p < 0.05). In the IRS-2 Gly1057Asp gene polymorphism, the G allele frequency was significantly higher in the DN patients than in the type 2 DM controls (p < 0.05). In the DN group, the individuals with one or less mutant alleles were significantly more than in the control group in terms of the IRS-2 Gly1057Asp gene polymorphism (p < 0.05). The C allele frequency for the MTHFR A1298C gene polymorphism and the G allele frequency for the IRS-2 Gly1057Asp gene polymorphism were indicated to be potential a genetic risk factor for the development of DN in patients with type 2 DM who developed DN.

Subcutaneous C.E.R.A. for the Treatment of Chronic Renal Anemia in Predialysis Patients

BACKGROUND We investigated the efficacy, safety and tolerability of once-monthly administration of C.E.R.A. in erythropoiesis stimulating agents (ESAs) naive predialysis patients with CKD for anemia treatment. STUDY DESIGN Single arm, open label study. METHODS A total of 75 patients (mean (SD) age was 52.8 (16.4) years, 76.0% were female) were included in this study conducted between 12 August 2008 and 30 October 2009 in 9 centers across Turkey. The mean change in Hb concentration (g/dL) between baseline (week 0) and the efficacy evaluation period (EEP) was the primary efficacy parameter evaluated in three consecutive periods including a dose titration period (DTP; with initial 1.2 μg/kg dose of C.E.R.A., subcutaneously, 28 weeks), EEP (8 weeks) and a long-term safety period (16 weeks). RESULTS Our analysis revealed an improvement in Hb levels from baseline value of 9.4 (0.4) g/dL to time adjusted average level of 11.4 (0.7) g/dL in EEP in the per protocol (PP) population and from 9.3 (0.5) g/dL to 11.1 (1.0) g/dL in intent-to-treat (ITT) population. Mean (SD) change in Hb levels from baseline to EEP was 2.0 (0.7) g/dl in the PP population (primary endpoint) and 1.7 (1.1) g/dL in the ITT population. The percentage of patients whose Hb concentrations remained within the target range of 10.0-12.0 g/dL throughout the EEP was 43.9% (95% CI: 28.5-60.3%) in the PP population and 38.7% (95% CI: 27.6% to 50.6%) in the ITP population. A total of 206 adverse events (AE) were reported in 77.0% of patients with hypertension (20%) as the most frequent AE. CONCLUSION Once-monthly subcutaneous C.E.R.A. administration is effective and safe in the treatment of anemia in pre-dialysis patients with CKD, who are not currently treated with ESAs.