Biomedical subjects

Marcin Renke

Publications and source records attributed to Marcin Renke.

8 recordsLinked to original sources

PubMed2006

Interrelationship between uremic toxicity and oxidative stress.

Uremic syndrome is associated with several metabolic disturbances. Oxidative stress is an important factor involved in the pathologic mechanism of these changes. The goal of this study was to understand the relationship between oxidative stress markers and two compounds included among uremic toxins. Two independent studies were performed, one with 29 peritoneal dialysis patients and the other with 43 predialysis subjects. In both groups of patients, known oxidative stress markers, malonyldialdehyde (MDA) and carbonyl groups (CG) formation were measured. Additionally, in the predialysis group, glutathione in erythrocytes (GSH) was estimated. In peritoneal dialysis patients, the concentration of advanced glycation end products (AGEs) was found to be significantly increased and correlated with both markers of oxidative stress. In predialysis patients, the increment of newly described uremic toxin purine nucleotide end products (Me2PY and Me4PY) were found and significant correlation was observed between both compounds versus MDA (positive) and GSH (negative). This relationship was visible especially in patients with more advanced renal failure. CG concentration was within the normal values and did not show any correlation with estimated toxin concentrations. In summary, results of both studies suggest that the interrelationship between uremic toxicity and oxidative stress is an important component of uremic syndrome. Nevertheless, further complex studies are needed to elucidate closer pathogenic links.

Aged↗

PubMed2005

Randomized, controlled study of the effects of losartan versus enalapril in small doses on proteinuria and tubular injury in primary glomerulonephritis.

BACKGROUND: Pharmacological blockade of the renin-angiotensin-aldosteron system ameliorates glomerular and tubulointerstitial damage. For optimal renoprotection, high doses of angiotensin II converting enzyme inhibitors and angiotensin II subtype 1 receptor antagonists are commonly recommended, but cannot always be administered. The aim of this study was to evaluate the effects of low-dose (25 mg) losartan on proteinuria and tubular injury extent. MATERIAL/METHODS: This was an open, randomized, 12-month study on the effects of 25 mg of losartan (n=19) vs. 10 mg of enalapril (n=14) as a control on proteinuria, urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG), and blood pressure in patients with primary glomerulonephritis. The second part of the study was an uncontrolled assessment of the renal effects of 50-mg administration of losartan. RESULTS: There were no significant differences between the groups in the effects on proteinuria and NAG excretion. Losartan and enalapril reduced proteinuria by 32.8% (p<0.029) and 40.9% (p<0.021), respectively, but did not affect NAG excretion. The antiproteinuric effect of losartan, achieved without changes in blood pressure, was particularly evident in subjects with proteinuria >1.5 g/24 h and normal blood pressure. 50 mg of losartan caused a significant decrease in NAG excretion vs. the baseline (p<0.027). CONCLUSIONS: 25 mg of losartan and 10 mg of enalapril equally reduce proteinuria. The significant antiproteinuric effect of losartan was achieved despite no changes in blood pressure. There were no differences between the drugs regarding their influence on tubular injury extent. 50 mg of losartan seems to be the minimal dose to improve tubular status.

Adult↗

PubMed2005

Low-dose dual blockade of the renin-angiotensin system improves tubular status in non-diabetic proteinuric patients.

OBJECTIVE: Treatment with agents that inhibit the renin-angiotensin system is commonly regarded as a gold standard renoprotective strategy in patients with chronic kidney diseases. For maximum antiproteinuric effect, the dose titration of these agents is recommended. This therapeutic strategy is not used for proteinuric patients who are not able to receive high doses of angiotensin-converting enzyme inhibitor or angiotensin II receptor antagonists. MATERIAL AND METHODS: In patients with primary glomerulonephritis (n=24), a randomized, triple-treatment, triple-period, cross-over study was performed to compare the effects of combined therapy with benazepril 5 mg and losartan 25 mg and monotherapy with either agent alone at a two-fold higher dose on the extent of tubular injury as assessed by alpha1-microglobulin (alpha1-m) excretion and the plasma level of transforming growth factor-beta1 (TGF-beta1). RESULTS: Combination therapy significantly reduced alpha1-m excretion compared to either agent used alone: 178.29+/-27.36 to 99.63+/-13.03 mg/g creatinine for losartan + benazepril vs 178.29+/-27.36 to 161.59+/-23.22 mg/g creatinine for benazepril alone (p<0.05; ANOVA) and 178.29+/-27.36 to 99.63+/-13.03 mg/g creatinine for losartan + benazepril vs 178.29+/-27.36 to 173.45+/-27.69 mg/g creatinine for losartan alone (p<0.05; ANOVA). There was a significant correlation between change in alpha1-m excretion and reduction in proteinuria (r=0.704; p=0.023). There were no differences in TGF-beta1 level between the studied treatments. Systemic blood pressure reduction did not differ among the therapies. CONCLUSIONS: Combination therapy with angiotensin-converting enzyme inhibitor and angiotensin II subtype 1 receptor antagonists at very small doses may be superior to monotherapy with these agents at higher doses as far as tubular injury is concerned. We speculate that such a therapeutic strategy may be a useful approach for patients who are known not to be capable of receiving optimal renoprotective doses of these regimens.

Adolescent↗

PubMed2005

[Groin hernia in the patients receiving CAPD].

Continuous ambulatory peritoneal dialysis (CAPD) is a popular way of treatment of the patients with renal failure. There were 1365 patients on CAPD in Poland in the year 2001. Higher frequency of groin and abdominal hernias was reported in those patients. 10% of dialysed patients developed hernia in the first five years of the therapy. The main problems of hernia repair in the CAPD patients are: increased pressure in abdominal cavity caused by dialysate volume, higher risk of peritonitis, poor prognosis in the complicated cases temporarily or permanently converted to hemodialysis (HD) and the insufficiency of healing process. Complications accorded to hernia repair are the third most often reason of conversion to HD. Conducted studies on hernia repair did not lead to the introduction of the world standard. Authors propose to introduce an unified protocol to improve treatment results. Main guidelines of hernia treatment in CAPD patients are: 1) consultation of the surgeon cooperating with dialysis center in qualification to CAPD, and in the case of hernia symptoms in CAPD patients, 2) application of tension-free methods (PHS recommended), 3) administration of antibiotic prophylaxis, 4) application of local or epidural anesthesia, 5) no necessity of discontinuation of CAPD procedures.

Antibiotic Prophylaxis↗

PubMed2004

Low-dose dual blockade of the renin-angiotensin system in patients with primary glomerulonephritis.

BACKGROUND: Treatment with agents interfering with the renin-angiotensin system retards the progressive course of proteinuric chronic renal disease. However, because of unwanted effects associated with such therapy, some patients cannot be treated with these drugs at all or may be administered only very small doses. To find an optimal nephroprotective strategy for these patients, we compared antiproteinuric effects of combination therapy with an angiotensin-converting enzyme inhibitor and angiotensin II type 1 receptor antagonist in very small doses with treatment with either agent alone at greater, but not maximal, doses. We compared the concomitant use of benazepril, 5 mg, and losartan, 25 mg, and monotherapy with these agents in doses 2-fold greater. METHODS: This is a randomized, open, crossover study of 3 treatments in 3 periods of 4 months each. Twenty-four patients with primary glomerulonephritis and nonnephrotic proteinuria, recognized previously as not able to be administered high doses of drugs from these classes, completed the protocol. RESULTS: Combined therapy decreased 24-hour proteinuria (-45.54% versus baseline) more effectively than either losartan (-28.17%; analysis of variance, P < 0.01) or benazepril (-20.19%; analysis of variance, P < 0.001) alone. Subgroup analysis showed that antiproteinuric effects of combination therapy, as well as losartan or benazepril alone, were significantly greater in patients with basal proteinuria greater than 2 g/24 h than in those with proteinuria less than this value (P < 0.001, P < 0.01, and P < 0.05, respectively). All therapies significantly decreased blood pressure (BP) compared with baseline, but there were no differences between treatments in BP changes. CONCLUSION: The study shows that combination therapy with very small doses of losartan and benazepril was more effective in reducing proteinuria than greater doses of either agent in monotherapy, and this greater antiproteinuric efficacy was independent of changes in BP.

Adult↗

PubMed2004

Low-dose angiotensin II receptor antagonists and angiotensin II-converting enzyme inhibitors alone or in combination for treatment of primary glomerulonephritis.

OBJECTIVE: The renin-angiotensin system is thought to be involved in the progression of chronic renal diseases of both diabetic and non-diabetic origin. It has been confirmed that angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) reduce urinary protein excretion and attenuate the development of renal injury. Clinical data comparing the renal effects of ACEIs and ARBs, either singly or in combination, are scarce and usually concern the use of standard or high doses. MATERIAL AND METHODS: This was a prospective, randomized, 9-month study of the effects of low doses of losartan (25 mg; n = 18) versus enalapril (10 mg; n = 18) versus the combination of losartan (25 mg) and enalapril (10 mg) (n = 16) on proteinuria, kidney function and metabolic profile in 54 patients with biopsy-proven chronic glomerulonephritis, hypertension and normal or slightly impaired kidney function. The clinical evaluation and laboratory tests were performed before treatment (baseline) and after 3 and 9 months of therapy. RESULTS: After 3 months, significant decreases in proteinuria were observed in all groups: losartan, 22.6% (p = 0.02); enalapril, 43% (p = 0.012); and combined therapy, 63% (p = 0.001). This anti-proteinuric effect was even greater after 9 months of therapy: losartan, 44.2% (p = 0.02); enalapril, 49.6% (p = 0.02); and combined therapy, 51% (p = 0.003). There was no significant difference between losartan and enalapril with respect to their impact on proteinuria level. Proteinuria reduction was significantly greater in patients receiving combined therapy in comparison with losartan treatment after 3 months of therapy (p = 0.02). Creatinine clearance and serum creatinine were stable during the entire study period in all patients. No significant changes in lipids, serum uric acid or protein levels were observed. CONCLUSIONS: These results indicate that proteinuria is reduced by low doses of losartan or enalapril. The combination of these drugs seems to be beneficial and may offer an additional renoprotective effect. This needs to be confirmed in a study with a larger sample size.

Adult↗

PubMed2002

Short-term effects of angiotensin II receptor blockade in patients with primary glomerulonephritis: pilot study.

OBJECTIVE: There is evidence that angiotensin II, the main effector of renin-angiotensin system, plays a crucial role in the pathogenesis of chronic renal injury. Angiotensin II type 1 (AT-1) receptor blockers reduce renin-angiotensin system activity by blocking the receptor, the activation of which is responsible for the majority of deleterious angiotensin II effects. The aim of the present study was to investigate renal and metabolic effects of specific AT-1 receptor blocker-losartan in patients with primary glomerulonephritis. DESIGN: Pilot clinical study. SETTING: Department of Nephrology, Transplantology and Internal Medicine, Medical University of Gdańsk, Poland. PARTICIPANTS: Fifteen patients aged 43.3 +/- 11.3 years with primary glomerulonephritis confirmed by renal biopsy were studied. INTERVENTION: Creatinine clearance, urinary excretion of protein and uric acid, urinary activity of N-acetyl-beta-D-glucosaminidase, and serum concentrations of lipids, protein, and uric acid were evaluated before and after 3 months of losartan (Cozaar; Merck Sharp & Dohme, Harlow, Essex, United Kingdom) treatment at a dose of 25 mg daily. RESULTS: We found a significant reduction of urinary excretion of protein (P <.008; average, 32%). Results also revealed a decrease of serum uric acid level (P <.01), probably as a consequence of elevated uric acid urinary excretion (P <.09). No significant changes in creatinine clearance, N-acetyl-beta-D-glucosaminidase activity, protein, or lipid levels were observed. CONCLUSION: We concluded that losartan treatment at a small dose of 25 mg daily produces antiproteinuric effect without adverse effects, notably with no decrease of glomerular filtration, and simultaneously induces beneficial changes in purine metabolism.

Adult↗

PubMedDate not supplied

Renoprotective effect of small doses of losartan and enalapril in patients with primary glomerulonephritis. Short-term observation.

BACKGROUND: The renin-angiotensin system is thought to be involved in progression of chronic renal diseases of both diabetic and nondiabetic origin. It is confirmed that angiotensin-converting enzyme inhibitors reduce urinary protein excretion (UPE) and attenuate the development of renal injury. The angiotensin II receptor blockers are an alternative class of drugs inhibiting the renin-angiotensin system activity with preliminarily confirmed renoprotective activity. However, there is lack of data concerning renoprotective action of very small doses of these drugs. METHODS: Prospective, randomized, 3-month study of the effects of losartan 25 mg (n = 17) vs. enalapril 10 mg (n = 17) vs. combination of losartan 25 mg and enalapril 10 mg (n = 15) on proteinuria, kidney function and metabolic profile in 51 patients with biopsy proven chronic glomerulonephritis with normal or slightly declined kidney function [creatinine clearance (CRCL) between 36 and 93 ml/min] was performed. Clinical evaluation and laboratory tests were estimated before treatment (basal), during the first week and after 3 months of therapy. RESULTS: Both, monotherpy with losartan and enalapril significantly reduced proteinuria by 25.35 and 45.07%, respectively. There was no significant difference between groups. Combined therapy induced a more remarkable reduction of proteinuria (65.96%) than either of the drugs administered alone. This antiproteinuric effect was significantly more pronounced only in comparison with the losartan group (p = 0.009). Decreasing of blood pressure was most pronounced in the combined group. In all groups, no correlation between fall of UPE and reducing the systolic or diastolic blood pressure was found. Significant decline in CRCL was observed with enalapril treatment just after 1 week of therapy (p = 0.039) and at the end of observation (p = 0.043). CRCL remained stable in losartan-treated subjects. No changes in serum creatinine level, metabolic profile and sodium excretion were observed during therapy in studied groups. CONCLUSIONS: These results indicated that even very small doses of losartan and enalapril reduce proteinuria in patients with primary glomerulonephritis. Combination of these drugs could cause significantly greater antiproteinuric effect than either of the agents in monotherapy. It is likely that the treatment with losartan, compared to enalapril, is associated with less risk of acute fall of glomerular filtration at the beginning of therapy.

Adult↗