The role of mammalian target of rapamycin pathway in the pathogenesis of pauci-immune glomerulonephritis.

Background: The characteristic lesion of pauci-immune glomerulonephritis is focal necrotizing and crescentic glomerulonephritis. The underlying mechanisms in the formation or progression of crescent formation need further investigations. Therefore, we aimed to evaluate the role of mammalian target of rapamycin (mTOR), which might be a potential therapeutic target, in kidney biopsies of patients with pauci-immune glomerulonephritis. Methods: The patients diagnosed as pauci-immune glomerulonephritis at an outpatient nephrology clinic were retrospectively reviewed and those patients who had a kidney biopsy before receiving an immunosuppressive treatment were included in the study. Kidney biopsy specimens were immunohistochemically stained with mTOR, antibodies of phosphatase and tensin homolog (PTEN) and transforming growth factor-ß (TGF-ß) and scored by an experienced renal pathologist. Results: In total, 54 patients with pauci-immune glomerulonephritis (28 [52%] female) were included. According to the histopathologic examination, 22% of our cases were classified as focal, 33% crescentic, 22% mixed, and 22% as sclerotic. The mTOR was expressed in substantial percentages of glomeruli of patients with pauci-immune glomerulonephritis. However, we observed PTEN expression in all samples and mTOR in all tubulointerstitial areas. mTOR expression was found to be related with the presence of crescentic and sclerotic changes observed in glomeruli and the degree of fibrosis in interstitial areas. Serum creatinine level or response to treatment was not found to be associated with mTOR pathway expression. Conclusion: Our results suggest that mTOR pathway may play role in the pathogenesis of pauci-immune glomerulonephritis, besides targeting this signaling may be an alternative option for those patients.

Screening Fabry's disease in chronic kidney disease patients not on dialysis: a multicenter study.

OBJECTIVES: Fabry's disease is an X-linked inherited, rare, progressive, lysosomal storage disorder, affecting multiple organs due to the deficient activity of α-galactosidase A (α-Gal A) enzyme. The prevalence has been reported to be 0.15-1% in hemodialysis patients; however, the information on the prevalence in chronic kidney disease not on dialysis is lacking. This study aimed to determine the prevalence of Fabry's disease in chronic kidney disease. METHODS: The patients older than 18 years, enclosing KDIGO 2012 chronic kidney disease definitions, not on dialysis, were enrolled. Dried blood spots on Guthrie papers were used to analyze α-Gal A enzyme and genetic analysis was performed in individuals with enzyme activity ≤1.2 µmol/L/h. RESULTS: A total of 1453 chronic kidney disease patients not on dialysis from seven clinics in Turkey were screened. The mean age of the study population was 59.3 ± 15.9 years. 45.6% of patients were female. The creatinine clearance of 77.3% of patients was below 60 mL/min/1.73 m2, 8.4% had proteinuria, and 2.5% had isolated microscopic hematuria. The mean value of patients' α-Gal A enzyme was detected as 2.93 ± 1.92 µmol/L/h. 152 patients had low levels of α-Gal A enzyme activity (≤1.2 µmol/L/h). In mutation analysis, A143T and D313Y variants were disclosed in three male patients. The prevalence of Fabry's disease in chronic kidney disease not on dialysis was found to be 0.2% (0.4% in male, 0.0% in female). CONCLUSION: Fabry's disease should be considered in the differential diagnosis of chronic kidney disease with unknown etiology even in the absence of symptoms and signs suggestive of Fabry's disease.

Cutaneous Alternariasis in a Patient With Renal Transplant.

INTRODUCTION: Alternaria is a common saprophyte, which is usually not pathogenic in humans. Generally, local wounds infections of Alternaria occur with presence of immunosuppression factors such as HIV infection and renal transplant patients. CASE PRESENTATION: We reported a case of wound infection induced by Alternaria spp. in a renal transplant patients. The main interest in this case was the rareness of the cutaneous alternariasis, its clinical aspects and good response to therapy. Recognition of Alternaria spp. as potential opportunistic pathogens is important for differential diagnosis of dermatological lesions, such as granulomatous or ulcerative lesions in immunocompromised patients. CONCLUSIONS: Alternariasis or similar cases may be increased due to the increased number of immunosuppressed patients. From this point of view, skin lesions in these patients must be planned and microbiologically evaluated considering the molds.

Prognostic value of glomerular C4d staining in patients with IgA nephritis.

INTRODUCTION: Mesangial IgA deposition is the initiative factor in the pathogenesis of IgA nephropathy (IgAN). Glomerular IgA depositon leads to activation local complement system. C4d positivity shows that complement activation occurs via alternative pathway. C4d positivity at the time of renal biopsy can be associated with poor prognosis in IgA nephropathy. We aimed to evaluate C4d deposition and renal outcome in patients with IgA nephritis. METHODS: Between January 2005 and December 2009, 40 patients with IgA nephritis were enrolled. Renal biopsy specimens of 33 patients have been evaluated. C4d immunohistochemical staining was performed 3-µm deparaffinized and rehydrated sections of formaldehyde-fixed renal tissues, using rabbit polyclonal anti-human C4d as the antibody. Baseline demographical, clinical and laboratory data were recorded retrospectively. RESULTS: Mean age of the patients was 35.9 ± 12.9 years and female/male ratio was 19/21. Mean duration of follow-up was 32.8 (12-60) months. Baseline glomerular filtration ratio (GFR) and proteinuria were 55.8 ml/min and 2.44 gr/day respectively at the time of renal biopsy. Eleven patients were C4d positive. Presence of hypertension (p=0.133), proteinuria (p=0.007), serum creatinine levels (p=0.056) and glomerulosclerosis (p=0.004), mesengial hypersellularity (p=0.0001) and interstitial fibrosis (p=0.006) at the time of renal biopsy were higher in C4d positive group rather than negative group. Evolution to renal failure were 63.6% in C4d positive group and 13.6% in negative group (p=0.006). Renal survival at 3 years was 39% in C4d-positive patients versus 66.7% in the C4d-negative patients (log rank- p=0.0072).

Association between hyperlactatemia and occult cardiac failure in diabetic patients on maintenance hemodialysis.

PURPOSE: Lactic acidosis as a consequence of high serum lactate levels may deepen the metabolic acidosis in patients with end-stage renal failure. Besides, certain antidiabetic may also cause raised lactate levels in diabetic patients. Therefore, it is obvious that the risk of hyperlactatemia is increased by folds in diabetic patients on chronic hemodialysis program. In this study, it is aimed to evaluate the frequency and the impact of increased serum lactate levels in prevalent diabetic hemodialysis patients. METHODS: A total of 100 diabetic patients who were under maintenance hemodialysis in five different dialysis centers were included in this study. All biochemical parameters, blood gas measurements, echocardiographic data and antidiabetic treatments were statistically analyzed in terms of serum lactate levels. RESULTS: Out of 100 patients, 12 patients had serum lactate levels over normal limits. When the patients with normal or high serum lactate levels were defined as two different groups, statistical significance was detected between serum lactate levels and serum sodium (p = 0.019), potassium (p = 0.037) and bicarbonate levels (p = 0.028). Moreover, in patients with hyperlactatemia, the ejection fraction value was found significantly low (p = 0.005). CONCLUSIONS: The frequency of hyperlactatemia was not rare in prevalent diabetic hemodialysis patients. We additionally found that serum lactate level measurement may particularly help to diagnose the occult cardiac failure. However, further large scale studies are required to define the clinical significance of hyperlactatemia in the end-stage renal failure patients with diabetes mellitus.

Quantitative evaluation of interstitial fibrosis with Sirius Red in IgA nephritis.

OBJECTIVE: Tubulointerstitial fibrosis is one of the strongest independent predictive factors in determining the prognosis in IgA nephritis. Recently, software-based quantitative measurement of interstitial fibrosis with Sirius Red staining has entered the practice. The objective of this study was to investigate the prognostic value of measurement of interstitial nephritis with this method in IgA nephritis. METHOD: Forty-three patients diagnosed with IgA nephritis with renal biopsy between the years 2005 and 2009 were included in this retrospective observational study. The diagnostic biopsies of 37 patients were examined. Basal data included age, gender, creatinine level, glomerular filtration rate (GFR), presence of proteinuria, hypertension, glomerulosclerosis, mesangial proliferation, and interstitial fibrosis and fibrosis index calculated by the measurement of computed images of Sirius Red positive areas. Final visit included evaluation of development of end-stage renal disease (ESRD), and GFR (whether = 60 mL/min or <60 mL/min). RESULTS: Numbers of patients with hypertension (75% vs. 34.5%; p = 0.050), ESRD development (62.5% vs. 20.7%, p = 0.035), GFR <60 mL/min (87.5% vs. 31%; p = 0.007) were greater; and basal GFR (34.25 ± 25.29 vs. 64.14 ± 35.34; p = 0.048) was lower in high-intensity interstitial fibrosis group (>1000 µm2) compared to low-intensity interstitial fibrosis group (≤1000 µm(2)). CONCLUSION: Quantitative analysis of computed imaging of areas of Sirius Red positive tubulointerstitial fibrosis might serve as an effective novel method to determine the prognosis in IgA nephritis.

Prognostic value of NGAL staining in patients with IgA nephropathy.

BACKGROUND: Renal tubulointerstitial injury plays an important role in disease progression of IgAN. Neutrophil gelatinase-associated lipocalin (NGAL) is a stress protein released by tubular cells. NGAL is a promising biomarker of acute kidney injury. There is a growing literature suggesting that NGAL is also a marker of chronic kidney disease and severity. Our aim was to evaluate the prognostic value of NGAL staining in patients with IgAN. METHODS: This retrospective study included all consecutive patients who underwent a renal biopsy at our center between January 2005 and December 2009. Forty-five patients with IgA nephritis were enrolled, and renal biopsy specimens of 29 patients were evaluated. We evaluated baseline age, sex, hypertension, serum creatinine, glomerular filtration rate (GFR), urine protein, NGAL staining, glomerulosclerosis, interstitial fibrosis, and extracapillary proliferation. The primary endpoint of this study was doubling of baseline serum creatinine and/or the onset of ESRD in the course of the study. At the end of the follow-up, patients whose estimated GFR (eGFR) was ≤15 mL/min/1.73 m(2) and/or baseline serum creatinine doubled, were defined as the progressor group. RESULTS: Nineteen patients (65.5%) were NGAL positive and 10 patients (34.5%) were NGAL negative. Female gender and hypertension were associated with NGAL-positive staining. Urinary protein excretion and serum creatinine levels were more elevated in the NGAL-positive group, but the difference was not significant. We found NGAL-positive staining in major proportion in the progressor group (88.9%) than the non-progressor group (55%) (p = 0.076). CONCLUSION: NGAL staining can be a new histological marker in IgAN progression.

Glomerular c4d staining can be an indicator of disease activity in lupus nephritis.

BACKGROUND: Abnormalities in complement activation and clearance of immune complexes by erythrocytes are the central pathogenic mechanisms in systemic lupus erythematosus (SLE). Serum C4d level, which is a degradation product of complement factor C4, was found to be a sensitive indicator of SLE activity. Our aim was to determine whether glomerular C4d staining could be a useful marker of disease activity in patients with lupus nephritis. METHODS: This retrospective study included all consecutive patients who underwent a renal biopsy at our center between January 2005 and December 2009. A total of 29 patients with IgA nephritis were enrolled, and renal biopsy specimens of 24 patients have been evaluated. We evaluated baseline age, sex, hypertension, serum creatinine level, glomerular filtration rate (GFR), urine protein, and glomerular C4d staining. The primary endpoint of this study was the onset of end-stage renal disease (ESRD) in the course of study. RESULTS: Fourteen (58%) patients were C4d+ and 10 (42%) patients C4d-. Urinary protein excretion was more elevated in C4d+ group (p = 0.0001). The renal biopsy showed that activity index score >12 was a higher proportion in C4d+ patients. The patients were followed up for 3.5 years. Four patients in the C4d+ group evolved to ESRD in the follow-up, but none of the patients in the C4d- group (p = 0.064). DISCUSSION: We found a relationship between glomerular C4d staining and activity of lupus nephritis. C4d staining may be a useful marker to predict the prognosis of lupus nephritis.

The value of serum immunoglobulin free light chain assessment in patients with monoclonal gammopathies and acute renal failure.

OBJECTIVE: Immunoglobulin free light chain (FLC) abnormalities are common in patients with monoclonal gammopathies and the kidneys are the most affected organs. Immunoassays that provide quantitative measurement of FLC in serum indicate monoclonal FLC production based on the presence of an abnormal FLC kappa:lambda (κ:λ) ratio. The aim of this study was to assess the utility of serum FLC measurement as a diagnostic tool for detecting plasma cell dyscrasias in comparison to standard assays, and to ascertain its sensitivity and specificity in patients with acute renal failure (ARF). MATERIAL AND METHODS: Sera from 82 patients with ARF were assessed using serum protein electrophoresis (SPE), serum immunofixation electrophoresis (SIFE), and FLC measurement. The sensitivity and specificity of the FLC ratio in identifying which ARF patients had multiple myeloma (MM) was compared to those of SPE and SIFE. RESULTS: Among the 82 patients with ARF, 7 were diagnosed as MM using SPE, SIFE, and bone marrow biopsy techniques. In total, 8 patients did not have a FLC κ:λ ratio that was within the published reference range (0:26-1:65); the FLC κ:λ ratio based on FLC measurement had a specificity of 96% and sensitivity of 71%, and positive and negative predictive values of 62.9% and 97.3%, respectively, for the diagnosis of MM. CONCLUSION: The sensitivity and specificity of the FLC κ:λ ratio for diagnosing MM in patients that presented with ARF were lower than those of SPE and SIFE. To further delineate the utility of the FLC κ:λ ratio additional prospective, well-designed large-scale studies are needed. CONFLICT OF INTEREST: None declared.

Preventive effect of nebivolol on contrast-induced nephropathy in rats.

BACKGROUND: Altered renal vasodilatation and oxidative stress are important mechanisms of contrast-induced nephropathy (CIN). The aim of the present study was to assess the effect of nebivolol, a beta blocker, on prevention of CIN. We hypothesized that nebivolol may prevent CIN due to its renal vasodilatation and antioxidant effects. METHODS: Thirty-two Wistar-albino rats were divided into four groups (n = 8 each): control (C), contrast media (CM), nebivolol (N), and nebivolol + contrast media (NCM). CIN was induced by administration of intravenous high-osmolar contrast media diatrizoate (6 ml/kg) after 72 h of dehydration. Nebivolol (2 mg/kg) was given internally once daily for 5 days. Kidney function parameters, nitric oxide metabolites and oxidative stress markers were measured. Kidneys were excised for pathological evaluation. RESULTS: The decrease of creatinine clearance was 0.180 +/- 0.11 mg/dl in CM, and 0.030 +/- 0.10 mg/dl in NCM (P = 0.01). Microproteinuria was ameliorated using nebivolol (P = 0.001). Serum protein carbonyl content, malonyldialdehyde and kidney thiobarbituric acid-reacting substances levels were higher in CM than in C (P = 0.003, P < 0.001 and P = 0.034, respectively) and serum thiol was lower in CM than in C (P = 0.001). However, oxidative stress markers were similar in NCM and C. Diatrizoate decreased kidney nitrite levels, but nebivolol increased them (P = 0.027). Nebivolol attenuated the tubular necrosis, proteinaceous casts and medullary congestion, although significant protective effects, were observed in tubular necrosis (P = 0.001) and proteinaceous cast (P < 0.001). CONCLUSION: This study demonstrated the protective role of nebivolol against CIN.

An unusual vascular involvement in a patient with Behcet's disease: renal artery stenosis.

Behcet's disease (BD) is a rare multisystem inflammatory disorder characterized by recurrent ulcers affecting the mouth and genitals, various skin lesions, relapsing iritis, and vasculitis. Vascular events may dominate the clinical presentation in some patients with BD. Hitherto three forms of vascular disease such as venous occlusions, arterial aneurysms, and arterial occlusions have been reported in BD. Renal vascular involvement has reported in less than 1% of the patients with vascular BD. A case of BD with renovascular hypertension is reported. To our knowledge, a case of BD with renovascular hypertension treated with angioplasty and stent implantation has not been reported previously.

Effect of vitamin E therapy on oxidative stress and erythrocyte osmotic fragility in patients on peritoneal dialysis and hemodialysis.

BACKGROUND: Several medications have been tested with the aim of decreasing oxidative stress and erythrocyte osmotic fragility in patients on dialysis. The aim of the present study was to assess the influence of vitamin E therapy on oxidative stress and erythrocyte osmotic fragility in patients on hemodialysis (HD) and peritoneal dialysis (PD). METHODS: This was a placebo-controlled study. The study was performed on 34 HD patients, 13 PD patients and 22 healthy volunteers with a mean age of 45.57 +/- 8.54 years. HD patients were divided into 2 groups: treatment (n=19) and control (n=15). Vitamin E was administered, 300 mg/day, to the HD treatment group and PD patients for 20 weeks. Lipid peroxidation, antioxidant condition and erythrocyte osmotic fragility (EOF) were examined before and after treatment. RESULTS: Before the treatment, the levels of EOF (p<0.001) and malondialdehyde (MDA) (p<0.001) were significantly lower, and erythrocyte superoxide dismutase (SOD) (p=0.001) and vitamin E levels (p<0.001) were significantly higher in the healthy group than PD and HD groups. Serum vitamin E increased from 0.93 +/- 0.16 to 1.09 +/- 0.14 mg/dL (p=0.001), EOF decreased from 0.49% +/- 0.03% to 0.42% +/- 0.04% NaCl (p<0.001), and plasma MDA values decreased from 2.77 +/- 0.87 to 2.20 +/- 0.767 nmol/mL (p=0.018) in the HD treatment group after vitamin E treatment. Levels of EOF decreased from 0.51% +/- 0.09% to 0.43% +/- 0.03% NaCl in the PD treatment group after vitamin E treatment (p=0.021). CONCLUSION: Vitamin E therapy is effective in decreasing the levels of EOF in patients on HD and PD, and it is also effective in decreasing lipid peroxidation in patients on HD.