Interferon-gamma+874 Polymorphism in the First Intron of the Human Interferon-gamma Gene and Kidney Allograft Outcome

Background. Despite advances in immunosuppressive therapy in the past decade, allograft rejection remains an important cause of kidney graft failure. Cytokines play a major role in the inflammatory and immune responses that mediate allograft outcomes. Several studies have shown that the production of cytokines varies among individuals. These variations are determined by genetic polymorphisms, most commonly within the regulatory region of cytokine genes. The aim of the present study was to assess the effect of allelic variation on acute rejection episodes (ARE) or chronic allograft nephropathy (CAN) after kidney transplantation. Methods. To determine a possible correlation between the interferon (INF)-gamma +874 polymorphism and kidney allograft outcome, we isolated genomic DNA from 74 patients who underwent isolated kidney allografts and were classified into 2 groups-a rejection and a nonrejection group-for comparison with a control group of 163 healthy subjects. Results. We genotyped INF-gamma +874 polymorphisms in all groups. The transplant group showed a significantly increased homozygous genotype T/T (P = .0118) compared with healthy controls. Similarly, considering only patients with CAN, the homozygous genotype T/T (P = .0067) was significantly increased compared with the healthy controls. The rejection group indicated a significant increased homozygous genotype Tic compared with the control group (P = .0061). Conclusion. Homozygous genotype T/T was associated with increased levels of INF-gamma and greater numbers among the rejection and CAN cohorts.

Glucocorticoid resistance in dialysis patients may impair the kidney allograft outcome

This study examines in vitro steroid sensitivity in chronic renal failure ( CRF) patients and its influence on the allograft outcome. We determined the inhibitory effect of dexamethasone ( DEX) on concanavalin A ( Con-A)-stimulated peripheral blood mononuclear cell ( PBMC) proliferation, and glucocorticoid receptor` ( GR) number of binding sites ( B-max) and affinity ( K-d) in 28 CRF patients and 40 normal healthy controls. Based on K-d values > 95th percentile from controls, patients were divided into two groups: glucocorticoid resistant ( n = 11) and glucocorticoid sensitive ( n = 17). Patients were followed during 18 months post-transplantation observing acute rejection episodes ( ARE), chronic allograft nephropathy ( CAN), allograft failure and death. The DEX concentration that caused 50% inhibition of Con-A-stimulated PBMC proliferation ( IC50) was higher in CRF than in healthy controls ( 2.2 x 10(-5) +/- 1.0 x 10(-5) versus 8.3 x 10(-6) +/- 4.2 x 10(-6) mol/ L, P = 0.02). Values of Kd ( 12.4 +/- 1.8 versus 7.2 +/- 0.9 nM) and Bmax ( 7.7 +/- 1.1 versus 4.1 +/- 0.3 fmol/ mg protein) were higher in CRF patients ( P = 0.02 and P = 0.001, respectively). There were higher incidences of ARE ( P = 0.02) and CAN ( P = 0.002) in the glucocorticoid-resistant group. Univariate and multivariate logistic regression showed that Kd was an independent predictor of ARE ( OR 8.8, P= 0.03) aswell as of CAN ( OR 16.5, P= 0.01). In conclusion, we observed glucocorticoid resistance in a subgroup of CRF patients undergoing dialysis, which led to a higher morbidity due to ARE and CAN in an 18-month follow-up period.

Evaluation of albuminuria and its relationship with blood pressure in dogs with chronic kidney disease

Background Microalbuminuria and hypertension have long been associated with a guarded prognosis in human patients with a variety of diseases. In veterinary medicine, tests for microalbuminuria have been used for detecting early kidney damage, but there is little information regarding its association with high blood pressure in dogs with chronic kidney disease (CKD). Objective The objective of this study was to evaluate albuminuria and its association with arterial hypertension in dogs with CKD. Methods Urinary albumin:creatinine (UAC) ratio, urinary protein:creatinine (UPC) ratio, and systolic blood pressure were determined in 39 clinically healthy dogs and 40 dogs with CKD. Results UAC in dogs with CKD (range, 0.002-7.99; median, 0.38) was statistically different from that of control dogs (range, 0.0005-0.01; median, 0.002). Microalbuminuria (UAC 0.03-0.3) and macroalbuminuria (UAC > 0.3) were detected in 32.5% and 50% of dogs with CKD, respectively. Sixty percent (24/40) of dogs with CKD had systolic pressure >= 180 mmHg; in these dogs, UAC ratio (range, 0.006-7.99; median, 1.72) was significantly higher than in dogs with CKD and systolic pressure < 180 mmHg (range, 0.002-4.83; median, 0.10). Of hypertensive dogs with CKD, those with UPC > 1.0 usually had macroalbuminuria, those with UPC 0.5-1.0 usually had microalbuminuria, and those with UPC < 0.5 usually lacked albuminuria. Conclusions UAC ratio was higher in hypertensive than in normotensive dogs with CKD. Tests designed to detect microalbuminuria may be useful for hypertensive dogs with CKD and a UPC < 1.0 to detect the onset and magnitude of albuminuria. Once macroalbuminuria is overt, the UPC ratio itself can be used for the same purpose.

Interacting roles of myofibroblasts, apoptosis and fibrogenic growth factors in the pathogenesis of renal tubulo-interstitial fibrosis

The interrelationship between myofibroblasts and fibrogenic growth factors in the pathogenesis of renal fibrosis is poorly defined. A temporal and spatial analysis of myofibroblasts, their proliferation and death, and presence of transforming growth factor-beta1 (TGF-beta1) and platelet-derived growth factor-B (PDGF-B) was carried out in an established rodent model in which chronic renal scarring and fibrosis occurs after healed renal papillary necrosis (RPN), similar to that seen with analgesic nephropathy. Treated and control groups (N = 6 and 4, respectively) were compared at 2, 4, 8 and 12 weeks. A positive relationship was found between presence of tubulo-interstitial myofibroblasts and development of fibrosis. Apoptotic myofibroblasts were identified in the interstitium and their incidence peaked 2 weeks after treatment. Levels of interstitial cell apoptosis and fibrosis were negatively correlated over time (r = -0.57, p < 0.01 ), suggesting that as apoptosis progressively failed to limit myofibroblast numbers, fibrosis increased. In comparison with the diminishing apoptosis in the interstitium, the tubular epithelium had progressively increasing levels of apoptosis over time, indicative of developing atrophy of nephrons. TGF-beta1 protein expression had a close spatial and temporal association with fibrosis and myofibroblasts, whilst PDGF-B appeared to have a closer link with populations of other chronic inflammatory cells such as infiltrating lymphocytes. Peritubular myofibroblasts were often seen near apoptotic cells in the tubular epithelium, suggestive of a paracrine toxic effect of factor/s secreted by the myofibroblasts. In vitro , TGF-beta1 was found to be toxic to renal tubular epithelial cells. These findings suggest an interaction between myofibroblasts, their deletion by apoptosis, and the presence of the fibrogenic growth factor TGF-beta1 in renal fibrosis, whereby apoptotic deletion of myofibroblasts could act as a controlling factor in progression of fibrosis.

Chronic glomerulonephritis associated with hepatosplenic schistosomiasis mansoni

In a series of 36 cases of renal disease associated with hepatosplenic schistosomiasis the following morphologic types of glomerulonephritis were found: mesangio-capillary (33.2%), mesangial proliferative (25.0%), focal glomerular sclerosis (16.7%) and sclerosing glomerulonephritis (8.3%). No significant statistical differences were found when these results were compared with those from 36 cases of glomerulonephritis not associated with hepatosplenic disease. On the other hand, endocapillary glomerulonephritis was found to be predominant in the latter group of cases. These results did not substantiate the assumption that mesangio-capillary glomerulonephritis is specifically related to hepatosplenic schistosomiais. However, if the types of glomerulonephritis that predominantly involve the me-sangium are considered together, they are significantly associated with hepatosplenic schistosomiasis. Mesangial involvement is known to occur in other parasitic diseases and that may be related to a common immunopathogenesis.

Nephrotic syndrome associated with hepatointestinal schistosomiasis

Schistosomal nephropathy has long been related to the hepatosplenic form of schistosomiasis. In the last few years, 24 patients with hepatointestinal schistosomiasis and the nephrotic syndrome were studied. Aiming at evaluating a possible etiologic participation of schistosomiasis in the development of the nephropathy, this group was comparatively studied with a group of 37 patients with idiopathic nephrotic syndrome. Both groups had a different distribution of the histologic lesions. In the group with schistosomiasis there was a statistically significant prevalence of proliferative mesangial glomerulonephritis (33.3%), whereas in the control group there was prevalence of membranous glomerulonephritis (32.4%). On immunofluorescence, IgM was positive in 94.4% of the patients with schistosomiasis versus 55.0% in the control group (p<0.01). In the group with schistosomiasis, 8 patients evidenced mesangial proliferative glomerulonephritis and 5, membra-noproliferative glomerulonephritis. In both histological types immunofluorescence showed IgM and C3 granular deposits in the glomeruli. The data in this study suggests that mesangial proliferative and membranoproliferative glomerulonephritis, with glomerular granular IgM and C3 deposits, represent the renal lesions of the schistosomiasis associated nephropathy.

Acute renal failure after massive honeybee stings

Two clinical cases of patients who survived after numerous attacks of Africanized bees (600 and 1500 bee stings, respectively) are reported. Clinical manifestation was characterized by diffuse and widespread edema, a burning sensation in the skin, headache, weakness, dizziness, generalized paresthesia, somnolence and hypotension. Acute renal failure developed and was attributed to hypotension, intravascular hemolysis, myoglobinuria due to rhabdomyolysis and probably to direct toxic effect of the massive quantity of injected venom. They were treated with antihistaminic, corticosteroids and fluid infusion. One of them had severe acute renal failure and dialysis was required. No clinical complication was observed during hospital stay and complete renal function recovery was observed in both patients. In conclusion, acute renal failure after bee stings is probably due to pigment nephropathy associated with hypovolemia. Early recognition of this syndrome is crucial to the successful management of these patients.

Clinical and Pathological Findings in Women with Fabry Disease

Introduction. Fabry disease is a rare metabolic disorder caused by the genetic deficiency of the lysosomal hydrolase alpha-galactosidase A, located on chromosome X. Females with the defective gene are more than carriers and can develop a wide range of symptoms. Nevertheless, disease symptoms generally occur later and are less severe in women than in men. The enzyme deficiency manifests as a glycosphingolipidosis with progressive accumulation of glycosphingolipids and deposit of inclusion bodies in lysosomes giving a myelinlike appearance. Patients and Methods. Records of renal biopsies performed on adults from 1st January 2008 to 31st August 2011, were retrospectively examined at the Renal Pathology Laboratory. We retrieved biopsies diagnosed with Fabry disease and reviewed clinical and laboratory data and pathology findings. Results. Four female patients with a mean age of 49.3±4.5 (44-55) years were identified. The mean proteinuria was 0.75±0.3 g/24h (0.4-1.2) and estimated glomerular filtration rate (CKD EPI equation) was 71±15.7 ml/min/1.73m2 (48-83). Three patients experienced extra-renal organ involvement (cerebrovascular, cardiac, dermatologic, ophthalmologic and thyroid) with distinct severity degrees. Leukocyte α-GAL A activity was below normal range in the four cases but plasma and urinary enzymatic activity was normal. Light microscopy showed predominant vacuolisation of the podocyte cytoplasm and darkly staining granular inclusions on paraffin and plastic-embedded semi-thin sections. Electron microscopy showed in three patients the characteristic myelin-like inclusions in the podocyte cytoplasm and also focal podocyte foot process effacement. In one case the inclusions were also present in parietal glomerular cells, endothelial cells of peritubular capillary and arterioles. Conclusion. Clinical signs and symptoms are varied and can be severe among heterozygous females with Fabry disease. Intracellular accumulation of glycosphingolipids is a characteristic histologic finding of Fabry nephropathy. Since this disease is a potentially treatable condition, its early identification is imperative. We should consider it in the differential diagnosis of any patient presenting with proteinuria and/or chronic kidney disease, especially if there is a family history of kidney disease.

Renal Pathology in Portuguese HIV-Infected Patients

HIV-infected patients may be affected by a variety of renal disorders. Portugal has a high incidence of HIV2 infection and a low prevalence of HIV-infected patients under dialysis treatment. The aim of this study was to characterise the type of renal disease in Portuguese HIV-infected patients and to determine if HIV2 infection is associated to renal pathology. Only 60 of the 5158 HIV-infected patients followed in our hospital underwent renal biopsy. Clinical and laboratory data and the type of renal disease were reviewed. Male gender was predominant (76.7%), as was Caucasian race (78.3%). Mean age was 37.9±10.6 years. The majority had criteria for AIDS, 66% were on combined antiretroviral therapy and 18.3% were on dialysis. The predominant lesions were immunecomplex glomerulonephritis (n=19), tubulointerstitial nephropathy (n=12), focal segmental glomerulosclerosis(n=11), followed by HIVAN (n=8). Other patterns(amyloidosis, vasculitis, minimal change lesion) were observed. Only three patients were HIV2 infected, and presented diabetic nephropathy, acute tubular necrosis and tubulointerstitial nephritis. No correlations between clinical findings and renal pathology were found. In conclusion, renal disease in HIV patients has a broad spectrum, and renal biopsy remains the gold standard for establishing the diagnosis and guide treatment. Renal disease is not frequent in HIV2-infected patients, and, when present, is probably not directly associated with HIV infection.

De Novo Hypertension and Decline of Renal Function in a Young Woman with Systemic Lupus Erythematosus and Antiphospholipid Syndrome

Antiphospholipid syndrome nephropathy and lupus nephritis have similar clinical and laboratory manifestations and achieving the accuracy of diagnosis required for correct treatment frequently necessitates a kidney biopsy. We report the case of a 29-year-old woman referred to the nephrology service for de novo hypertension, decline of renal function and proteinuria. She had had systemic lupus erythematosus and antiphospholipid syndrome since the age of 21 and was taking oral anticoagulation. Two weeks later, after treatment of hypertension and achievement of adequate coagulation parameters, a percutaneous renal biopsy was performed. The biopsy revealed chronic lesions of focal cortical atrophy, arterial fibrous intimal hyperplasia and arterial thromboses, which are typical features of antiphospholipid syndrome nephropathy. We describe the clinical manifestations and histopathology of antiphospholipid syndrome nephropathy and review the literature on renal biopsy in patients receiving anticoagulation.

Diabetes Mellitus and Renal Disease: When to Perform a Renal Biopsy?

Background: Several studies suggest that nondiabetic renal disease (NDRD) is common in patients with diabetes mellitus. The aim of this analysis of renal biopsies in diabetic patients was (a) to assess the prevalence and type of NDRD and (b) to identify its clinical and laboratory predictors. Methods: This retrospective study analysed clinical and laboratory data and biopsy findings in diabetic patients observed by a single pathologist over the past 25 years. Based on biopsy findings, patients were categorised as (i) isolated diabetic nephropathy,(ii) isolated NDRD and (iii) NDRD superimposed on diabetic nephropathy. Results: Of the 236 patients studied, 60% were male and the mean age was 56.3 (±14.2) years. Of these, 91% had known diabetes mellitus at the time of biopsy (13% type 1 and 87% type 2). Isolated diabetic nephropathy was found in 125 (53%), isolated NDRD in 89 (38%) and NDRD superimposed on diabetic nephropathy in 22 (9%) patients. The main indication for biopsy in the three groups was nephrotic proteinuria. Patients with isolated NDRD and NDRD superimposed on diabetic nephropathy presented acute deterioration of renal function more frequently (p<0.001) and had more microhaematuria(p<0.001) as indications for renal biopsy. Focal segmental glomerulosclerosis and membranous nephropathy were the most frequent diagnoses in patients with NDRD. Patients with isolated diabetic nephropathy were younger (p=0.02), presented a longer duration of diabetes mellitus (p<0.001) and had more frequent retinopathy (p<0.001). The prevalence of microhaematuria was higher in patients with isolated or superimposed NDRD (p=0.01). Conclusion: The prevalence of NDRD (either isolated or superimposed on diabetes mellitus) is remarkably frequent in diabetic patients in whom nephrologists consider renal biopsy an appropriate measure. Predictors of NDRD were older age, shorter duration of diabetes mellitus, absence of retinopathy and presence of microhaematuria.

Demographic and Clinical Characteristics of Human Immunodeficiency Virus-Infected Patients Receiving Dialysis in Portugal: a Nationwide Multicentre Survey

Background: Data on human immunodeficiency virus (HIV) infected patients receiving dialysis in Portugal is scarce. Methods: This nationwide epidemiological survey retrospectively evaluates HIV-infected patients on chronic dialysis in Portugal between 1997 and 2002. Results: Sixty-six patients were evaluated (mean age: 39.1±1.6 years, 47 men, 35 black African). Sixty-two patients started dialysis and 4 patients who were receiving dialysis had HIV seroconversion. Eighty-five percent of patients were treated in Lisbon. The annual incidence of HIV-infected patients on chronic dialysis was 0.5% in 1997 and 0.9% in 2002. Seventy-eight percent of patients were HIV-1 infected , 13% had hepatitis B and 31% hepatitis C. Sexual contact was the mode of transmission of HIV in 53% of cases. Four patients had biopsy-proved HIV-associated nephropathy. Ninety-five percent of patients were on chronic hemodialysis. Fifty percent of patients had acquired immunodeficiency syndrome. At follow-up, 12 patients died. HIV-infected CKD patient survival after starting dialysis was 80% at 3 years. Conclusion: The incidence of HIV-infected patients on chronic dialysis in Portugal has almost doubled. Widespread use of highly active antiretroviral therapy and the increasing number of black Africans from former overseas Portuguese colonies now living in Portugal are possible reasons for this large increase.

Renal Disease in Madeira Islands: Twenty-Seven Years' Experience of Native Kidney Biopsies

Introduction: Renal biopsy plays an essential role either in the diagnosis or in the prognosis of patients with renal disease. In order to assess its epidemiology and evolution in Madeira Islands, we analysed twenty-seven years of native kidney biopsies. Methods: We performed a retrospective analysis of clinical records, including histological revision from 1986 to 2012, totalling 315 native kidney biopsies. They were assessed regarding the temporal evolution both for the quality/indications for renal biopsy and for the patterns of kidney disease. Results: A total of 315 native kidney biopsies were analysed. The patients’ mean age was of 40.8 ± 18.4 years and 50.5%(n = 159) were males. The most common indications for renal biopsy were nephrotic syndrome (36.2%, n = 114) and acute kidney injury (20.0%, n = 63). Among primary glomerular diseases (41.5%, n = 115) the most common were IgA nephropathy (26.1%, n = 30) and focal-segmental glomerulosclerosis (17.4%, n = 20) and among secondary glomerular diseases (31.4%, n = 87), lupus nephritis (51.7%, n = 45) and amyloidosis (20.7%, n = 18). Statistical analysis revealed significant correlation between gender and major pathological diagnosis (Fisher’s exact test, p <.01) and between indications for renal biopsy and major pathological diagnosis (χ2, p <.01). Regarding the temporal evolution, no statistically significant differences were found in the number of renal biopsies (χ2, p =.193), number of glomeruli per sample (Fisher’s exact test, p =.669), age (Kruskal-Wallis, p =.216), indications for renal biopsy (χ2, p =.106) or major pathological diagnosis groups (χ2,p =.649). However, considering the specific clinico-pathological diagnoses and their temporal variation, a statistically significant difference (Fisher’s exact test, p <.05) was found for lupus nephritis and membranous nephropathy with an increasing incidence and for amyloidosis with an opposite tendency. Discussion: The review of the native kidney biopsies from a population with particular characteristics, geographically isolated, such as those from Madeira Islands, showed parallel between epidemiological numbers referring to other European subpopulations, allowing simultaneously a comprehensive approach to our renal biopsy policies.

Disruption of Urate Transport in Familial Renal Glucosuria and Report on SGLT2 Expression in Normal and Pathological Kidney

Familial renal glucosuria (FRG) is a rare co -dominantly inherited benign phenotype characterized by the presence of glucose in the urine. It is caused by mutations in the SLC5A2 gene that encodes SGLT2, a Na+ -glucose co -transporter. The purpose of our current work was twofold: to characterize the molecular and phenotype findings of an FRG cohort and, in addition, to detail the SGLT2 expression in the adult human kidney. The phenotype of FRG pedigrees was evaluated using direct sequencing for the identification of sequence variations in the SLC5A2 gene. The expression of SGLT2 in the adult human kidney was studied by immunofluorescence on kidney biopsy specimens. In the absence of renal biopsies from FRG individuals, and in order to evaluate the potential disruption of SGLT2 expression in a glucosuric nephropathy, we have selected cases of nucleoside analogues induced proximal tubular toxicity. We identified six novel SLC5A2 mutations in six FRG pedigrees and described the occurrence of hyperuricosuria associated with hypouricaemia in the two probands with the most severe phenotypes. Histopathological studies proved that SGLT2 is localized to the brush -border of the proximal tubular epithelia cell and that this normal pattern was found to be disrupted in cases of nucleoside analogues induced tubulopathy. We present six novel SLC5A2 mutations, further contributing to the allelic heterogeneity in FRG, and identified hyperuricosuria and hypouricaemia as part of the FRG phenotype. SGLT2 is localized to the brush -border of the proximal tubule in the adult human normal kidney, and aberrant expression of the co -transporter may underlie the glucosuria seen with the use of nucleoside analogues.