Role of fluid-phase complement system regulation in the development of hepatitis C virus-associated glomerulonephritis.

OBJECTIVES: It is not known why only some hepatitis C virus (HCV) infected patients develop glomerulonephritis (GN). Therefore, we investigated the role of soluble complement regulators in the development of HCV associated GN. METHODS: Patients with HCV associated GN who were admitted to our nephrology unit between July 2016 and July 2018 were recruited to the study (group 1). Two other age and sex matched groups were studied as control groups: patients with HCV without GN (group 2) and healthy HCV negative volunteers (group 3). There were 26 participants in each of the three groups at the end of the recruitment period. An assay of serum fluid-phase complement regulators was performed using enzyme linked immunosorbent assay technique. Three complement single nucleotide polymorphisms (SNPs) were analyzed using real time polymerase chain reaction (Taqman; thermo fisher scientific): rs2230199 and rs1047286 for complement 3 (C3) and rs800292 for complement factor H (CFH). RESULTS: Serum levels of complement 4 binding protein (C4BP) were significantly lower in group 1 (median 70 ng/ml) than in groups 2 (median 88.8 ng/ml) and 3 (median 82.8 ng/ml) with p value of 0.007. The minor allele (allele A) of rs800292 for CFH was significantly higher in group 2 and group 3 (G 54% and A 46%) than in group 1 (G 73% and A 27%), p = 0.04. CONCLUSIONS: Low C4BP levels are associated with GN in HCV infected patients. In addition, rs800292 SNP in CFH protects against GN in patients with HCV.

Genetic polymorphism in C3 is associated with progression in chronic kidney disease (CKD) patients with IgA nephropathy but not in other causes of CKD.

OBJECTIVES: The R102G variant in complement 3 (C3) results in two allotypic variants: C3 fast (C3F) and C3 slow (C3S). C3F presents at increased frequency in patients with chronic kidney disease (CKD), our aim is to explore its role in CKD progression and mortality. METHODS: Delta (Δ) eGFR for 2038 patients in the Salford Kidney Study (SKS) was calculated by linear regression; those with ≤-3ml/min/1.73m2/yr were defined as rapid progressors (RP) and those with ΔeGFR between -0.5 and +1ml/min/1.73m2/yr, labelled stable CKD patients (SP).A group of 454 volunteers was used as a control group. In addition, all biopsy-proven glomerulonephritis (GN) patients were studied regardless of their ΔeGFR. R102G was analysed by real-time PCR, and genotypic and allelic frequencies were compared between RP and SP along with the healthy control group. RESULTS: There were 255 SP and 259 RP in the final cohort. Median ΔeGFR was 0.07 vs. -4.7 ml/min/1.73m2/yr in SP vs. RP. C3F allele frequency was found to be significantly higher in our CKD cohort (25.7%) compared with the healthy control group (20.6%); p = 0.008.However, there was no significant difference in C3F allele frequency between the RP and SP groups. In a subgroup analysis of 37 patients with IgA nephropathy in the CKD cohort (21 RP and 16 SP), there was a significantly higher frequency of C3F in RP 40.5% vs. 9.4% in SP; p = 0.003. In the GN group, Cox regression showed an association between C3F and progression only in those with IgA nephropathy (n = 114);HR = 1.9 (95% CI 1.1-3.1; p = 0.018) for individuals heterozygous for the C3F variant, increased further for individuals homozygous for the variant, HR = 2.8 (95% CI 1.2-6.2; p = 0.014). CONCLUSION: The C3 variant R102G is associated with progression of CKD in patients with IgA nephropathy.

Occurrence of the polyomavirus among kidney transplant recipients: a single-center study.

Polyoma virus-associated nephropathy is an increasingly recognized cause of graft dysfunction among kidney transplant recipients and could be the result of use of potent immunosuppression following transplantation. Because there is no safe and effective anti-viral therapy available presently, screening-based prevention and pre-emptive strategy are recommended. This study, which was conducted at the Nephrology Unit, Internal Medicine Department, Alexandria University, consisted of two phases: Phase 1 was a cross-sectional study and phase 2 was a 6-month follow-up study only for polyoma virus-positive cases. Phase 1 included 75 renal allograft recipients from living donors. Urine cytology for decoy cells and quantitative real-time blood polymerase chain reaction (PCR) for the BK virus (BKV) were performed on all the study patients. Renal biopsy was performed only in patients with deteriorating renal function associated with positive urine cytology. Patients who showed positive urine cytology for decoy cells and/or positive quantitative BKV PCR assay were followed-up for six months. During follow-up, the serum creatinine level, with or without urine cytology for decoy cells, and BKV PCR viral load assay were performed. Among the 75 kidney transplant recipients studied, eight were positive for decoy cells (11%), three showed viremia by quantitative PCR for BKV (4.1%), while two others showed nephropathy (2.7%) in the form of tubulointerstitial nephritis with intra-nuclear inclusions in the tubular cells. Cases with stable renal function and positive decoy cells or viremia cleared the virus spontaneously during follow-up without any intervention. Only one case with biopsyproven nephropathy and deteriorating graft function, with undetectable BKV in blood, lost the graft while another case with viremia died during follow-up due to septicemia. Our study suggests that polyoma virus should be considered as a cause of nephropathy in renal transplant recipients. Further research is required to understand this entity better.

Fasting the month of Ramadan by Muslims: could it be injurious to their kidneys?

Ramadan is the ninth lunar month of the Islamic calendar. During Ramadan, Muslims abstain from food and drink from dawn to sunset (fasting) to express their gratitude to God; eating and drinking is permitted only at night. Muslims typically consume two meals each day, one after sunset, and the other just before dawn. The effect of fasting during the month of Ramadan on patients with renal impairment is still a matter of controversy. This is a prospective study performed on 15 predialysis chronic kidney disease (CKD) patients and six healthy volunteers as control. They were studied during two phases: when the subjects were drinking and eating freely before the start of Ramadan, and a second phase toward the end of Ramadan. We estimated glomerular filtration rate (GFR) using DTPA dynamic renal scan, and tubular cell damage by measuring the level of N-acetyl-B-D- glucosaminidase (NAG). The change in glomerular filtration rate was -6.56 +/- 31.10 in the CKD group compared to 9.58 +/- 30.10 in the control group with no significant difference between them (p= 0.43). However, the urinary NAG percentage change was found to be significantly higher in the CKD patients compared to the control group (236 +/- 332, -49.1 +/- 60.1 respectively p= 0.03). There was a significantly positive correlation between the NAG values and the change in the blood glucose level (p=0.001), hence diabetic CKD patients should be meticulously followed during Ramadan fasting. In conclusion, fasting Ramadan may have injurious effect on the renal tubules in CKD patients. Larger studies are recommended to determine the extent of tubular injury and renal function in CKD patients during Ramadan fasting.

Comparative clinical prospective therapeutic study between cyclophosphamide, cyclosporine and azathioprine in the treatment of lupus nephritis.

Systemic Lupus Erythrematosus (SLE) is an inflammatory autoimmune disorder that may affect multiple organ systems. The clinical course is marked by spontaneous remission and relapses. Severity may vary from mild episodic disorder to a rapidly fulminant life threatening illness. Clinical manifestations of Lupus Nephritis (LN) are varied according to the renal pathologic lesions. Treatment of LN remains controversial. As a chronic disease with periods of remission and relapses, it is unclear whether relapses should be treated as the initial presentation of the disease. This prospective study was designed to compare between three different modalities of therapy for treating LN patients. The study includes all systemic lupus patients seen in Alexandria University Hospital since January 2004 for 6 months. Forty-three patients with SLE were presented to us by SLE, only 31 had LN and 22 were included in the study. The patients were classified randomly into 3 arms. All patients received steroid therapy plus from the beginning either Cyclophosphamide (CYP) [Group I, n=7], or Cyclosporine (CsA) [Group II, n=7], or Azathioprine (AZA) [Group III, n=8], Full history and examination were done. Laboratory investigations included routine and immunological studies of ANA, Anti-DNA, C3 and C4. Renal biopsy was done in all patients. After 6 months of follow up; Serum creatinine was stationary in CYP group from 2.2 +/- 1.1 to 2.1 +/- 1.7; while significantly decreased in CsA from 2.8+1.7 to 1.0 +/- 0.5 mg/dl. Moreover; while proteinuria decreased in CYP from 2.7 +/- 0.7 to 1.8 +/- 2.2; there was more pronounced decreased from 6.9 +/- 10.0 to 2.4 +/- 1.2 g/24 hr in CsA group despite very huge increase in glomerular filtration rate (GFR). 2 out 7 cases of CsA group; while 2 of 6 of CYP group did not show improvement. Moreover; 3 of 6 of CYP group and 1 of 6 of AZA group needed to be shifted to CsA group because of side effects and/or no response to CYP and showed good response. These patients were either class V or IV. However; only one case in this study with signs of acute CsA toxicity was reversed by monitoring the dose. In conclusion, CsA in this study proved to be superior over CYP in LN at least in the short term follow up; provided to be given with appropriate doses even if it is used in class IV, which was thought to be very responsive to CYP.

In salt-sensitive hypertension, increased superoxide production is linked to functional upregulation of angiotensin II.

The balance between endothelial nitric oxide (NO) and angiotensin II (Ang II) maintains the homeostasis of the cardiovascular and renal systems. We tested the hypothesis that increased oxidant stress linked to a functional imbalance between NO and Ang II might play a central pathogenetic role in salt-sensitive (SS) hypertension. We studied Dahl SS (DS) rats during the prehypertensive (5 days) and hypertensive (12 weeks) phases of a high-salt (4% NaCl) diet. Control rats received a normal-salt (0.5% NaCl, [NS]) diet. Prehypertensive DS rats (systolic blood pressure [SBP] 138+/-2 mm Hg) manifested a 35% increase (P<0.05) in aortic superoxide (O2-) production without evidence of end-organ damage. Hypertensive DS rats (SBP 214+/-11 mm Hg) had impaired endothelium-dependent relaxation (EDR) and increased aortic O2- production (320%), urinary isoprostane excretion (83%), aortic (20%) and left ventricular (LVH, 21%) hypertrophy, and proteinuria (124%). In prehypertensive DS rats, candesartan (10 mg x kg(-1) x d(-1)) an Ang II type 1 receptor blocker (ARB), normalized O2- production. In hypertensive DS rats, the ARB decreased aortic O2- production by 71% and normalized EDR without affecting SBP (212+/-8 mm Hg), aortic hypertrophy, LVH, or proteinuria. Switching hypertensive DS rats to an NS diet did not affect SBP (208+/-8 mm Hg), LVH, aortic hypertrophy, or proteinuria and had minimal effects on O2- and EDR. Concomitant ARB administration plus a switch to an NS diet normalized SBP (138+/-8 mm Hg) as well as end-organ damage. Dahl salt-resistant rats fed an HS diet for 12 weeks did not show hypertension or increased O2- production. Thus, SS hypertension might represent a specific vascular diathesis linked to functional upregulation of Ang II action (increased O2- synthesis) accompanied by insufficient NO bioavailability, which promotes severe endothelial dysfunction.

Tissue transglutaminase and the progression of human renal scarring.

Experimental renal scarring indicates that tissue transglutaminase (tTg) may be associated with the accumulation of extracellular matrix (ECM), both indirectly via TGF-beta1 activation and directly by the formation of epsilon(gamma-glutamyl) lysine dipeptide bonds within the ECM. The latter potentially accelerates deposition and confers the ECM with resistance to proteolytic digestion. Studied were 136 human renal biopsy samples from a range of chronic renal diseases (CRD) to determine changes in tTg and epsilon(gamma-glutamyl) lysine crosslinking. Immunofluorescence for insoluble tTg showed a 14-fold increase in the kidneys of CRD patients (5.3 +/- 0.5 versus 76 +/- 54 mV/cm(2)), which was shown to be active by a similar 11-fold increase in the epsilon(gamma-glutamyl) lysine crosslink (1.8 +/- 0.2 versus 19.3 +/- 14.2 mV/cm(2)). Correlations were obtained with renal function for tTg and crosslink. In situ hybridization for tTg mRNA showed that tubular epithelial cells were the major source of tTg; however, both mesangial and interstitial cells also contributed to elevated levels in CRD. This mRNA pattern was consistent with immunohistochemistry for soluble tTg. Changes in renal tTg and its product, the epsilon(gamma-glutamyl) lysine crosslink, occur in progressive renal scarring in humans independently of the original etiology and in a similar manner to experimental models. tTg may therefore play a role in the pathogenesis of renal scarring and fibrosis in patients with CRD and can therefore be considered a potential therapeutic target.

Cytoskeletal protein expression and regenerative markers in schistosomal nephropathy.

BACKGROUND: Progression of renal diseases is related to the abnormal regulation of cellular and extracellular matrix turnover. Other factors in addition to schistosomal antigens may be relevant to the progression of schistosomal nephropathy (SN). The validity of markers of fibroblastic differentiation, alpha smooth muscle actin (alphaSMA), and vimentin, as well as the regenerative activity (PCNA/apoptosis index) in determination of progression of SN in comparison to other forms of non-schistosomal nephropathy (non-SN) is investigated. METHODS: Three groups were included; group I pure SN (n=16), group II a diverse group of non-schistosomal patients with comparable pathologic changes on renal biopsy (n=40) and a control group (n=5). Immunohistochemical staining of myofibroblasts (alphaSMA and vimentin) and proliferating cells (PCNA) and histomorphometric analysis was done. In situ end labelling (ISEL) of DNA was used to evaluate apoptosis. RESULTS: No differences in the patterns of distribution of positivity of the different studied markers were observed between the different nephropathy groups. Both alphaSMA and vimentin were detected in glomerular mesangial, tubular epithelial, interstitial inflammatory fibroblast-like cells and occasionally endothelial cells. PCNA and apoptotic cells were detected in tubular epithelial and interstitial cells with paucity of positive cells in the glomerulus. Significant positive correlations were detected in group I between glomerular sclerosis and interstitial markers including interstitial alphaSMA (r=0.609, P=0.001), interstitial vimentin (r=0.812, P=0.00) and interstitial apoptosis (r=0.733, P=0.001). On the other hand, glomerulosclerosis in group II showed significant positive correlations with predominantly the glomerular markers; glomerular alphaSMA (r=0.475, P=0.002), glomerular apoptosis (r=0.684, P=0.00) and glomerular PCNA (r=0.691, P=0.00). Interstitial fibrosis correlated significantly with interstitial markers in group I including interstitial alphaSMA (r=0.837, P=0.00) interstitial vimentin (r=0.929, P=0.00), interstitial apoptosis (r=0.807, P=0.00) and interstitial PCNA (r=0.617, P=0.01), while in group II it correlated with both interstitial and glomerular markers. In addition, the tubulo-interstitial ratio was significantly higher in group I in comparison with group II (P=0.024), with no difference between groups II and III. CONCLUSIONS: Although SN may start as glomerulopathy associated with increased mesangial cellularity, the interstitial rather than the glomerular markers of myofibroblastic differentiation and those of cell turnover are playing a crucial role in late stages of schistosomal, but not in non-schistosomal nephropathies.