Urinary proteome and potential biomarkers associated with serial pathogenesis steps of focal segmental glomerulosclerosis.

BACKGROUND: Focal segmental glomerulosclerosis (FSGS) is a chronic nephropathy showing characteristic glomerular sclerosis. So far, the diagnosis and prognosis of FSGS rely mainly on the invasive biopsy. Searching for potential FSGS-associated urinary biomarkers representing pre-sclerotic and serial sclerotic stages of FSGS could be helpful to the non-invasive diagnosis and prognosis of FSGS. METHODS: In the present study, we used a 2D gel-based proteomic approach to identify urinary proteins at pre-sclerotic and different sclerotic stages of an FSGS mouse model in order to find FSGS-related urinary proteins. The FSGS mouse model was established in Balb/c mice by a single injection of adriamycin, and disease severity was monitored by renal biological parameters and histopathological features. Urine was collected on days 0, 4, 7, 11, 15 and 20, and subjected to two-dimensional electrophoresis (2-DE) analysis. Proteins were identified by matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF MS) and a protein database search. Some of the identified proteins were confirmed by western blot analysis. RESULTS: We identified 37 urinary proteins showing characteristic patterns of dynamic changes along the disease course of FSGS. Early urinary proteins appearing before glomerular sclerosis were noticed. Importantly, 11 urine proteins are novel to FSGS and have known functions highly associated with different pathogenetic steps of the disease, including haemodynamic disturbance, podocyte apoptosis, ECM-protein deposition and glomerular sclerosis. CONCLUSIONS: Some urinary proteins appearing earlier than glomerular sclerosis could serve as potential early diagnostic biomarkers. The proteins with the pathogenic roles could serve as potential non-invasive prognostic markers of FSGS, and give an insight into pathogenic mechanisms of this sclerosis disease.     

Long‐term outcome of renal transplantation in adults with focal segmental glomerulosclerosis

Little information is available about the long‐term results of kidney transplantation in adults with focal segmental glomerulosclerosis (FSGS). The outcomes of 52 renal transplants performed between 1988 and 2008 in 47 adults with FSGS were compared with those of 104 matched controls (median follow‐up 93.4 vs. 109.4 months respectively). At 15 years, patient survival was 100% and graft survival 56% in FSGS patients vs. 88.3% and 64% respectively in controls (P = NS). FSGS recurred in 12 out of 52 grafts (23%) and led to graft failure in seven within 10 months (median). In the other five cases, proteinuria remitted and grafts are functioning 106 months (median) after transplantation. A second recurrence developed in five out of eight re‐transplanted patients (62.5%) who lost their first graft because of recurrence; only one graft was lost. Patients with recurrence were more frequently male subjects (83% vs. 40%, P = 0.02), younger at diagnosis of FSGS (16.3 ± 6.8 vs. 24.1 ± 11.5 years, P = 0.03) and of younger age at transplantation (28.4 ± 7.8 vs. 35.8 ± 12.2 years, P = 0.05). Treatment with plasmapheresis plus ACE inhibitors achieved either complete or partial remission in 80% of the cases. Long‐term patient and renal allograft survivals of adults with FSGS were comparable to those of controls. Recurrence was more frequent in young patients and in patients who lost a previous graft from recurrence. Graft loss resulting from a second recurrence is lower than expected.     

Influence of angiotensin converting enzyme inhibitor treatment on cardiac autonomic modulation in patients receiving haemodialysis

BACKGROUND: Cardiovascular disease mortality among patients with end stage renal disease (ESRD) exceeds that which is predicted by traditional risk factors. Sudden death accounts for up to 15-38% of patients with ESRD found dead at home. Heart rate variability (HRV) is a reliable measure of autonomic modulation and has a very strong predictive value for ventricular arrhythmias and sudden death. A lower HRV is associated with increased risk. Modifying autonomic tone pharmacologically reduces death from dysrhythmia in the general population but has not been studied in ESRD. METHODS: We examined the effect of ramipril, an angiotensin converting enzyme inhibitor (ACEI) known in the general population to increase HRV, on cardiac function and heart rate variability in patients with renal failure. Eligible subjects on haemodialysis underwent a 2-week washout period free of ACEI or beta blockers, during which time hypertension was treated with amlodipine, which has been shown not to affect HRV. Haemodynamic and HRV measurements were obtained at baseline and after subjects were treated for 4 weeks with an ACEI. RESULTS: Haemodynamics did not differ at 0 and 4 weeks. Baseline HRV values were markedly below those found in the general population, indicating pronounced predominance of sympathetic tone over vagal tone. Actual worsening of HRV with ACEI treatment was evident in several major time domains. The time domain SDNN (the standard deviation of all normal RR intervals) fell from 42.0 +/- 24.8 ms to 20.1 +/- 16.1 ms (P = 0.004) and the triangulation index fell from 178.0 +/- 94.0 to 115 +/- 59.2 (P = 0.01). A trend toward reduced HRV was seen in several other time domains. CONCLUSION: These findings suggest that, unlike the general population, treatment of ESRD patients with an angiotensin converting enzyme inhibitor may cause a deleterious shift toward increased cardiac sympathetic nervous system tone.     

Biomarkers of endothelial dysfunction in patients with primary focal segmental glomerulosclerosis

Aim: Endothelial dysfunction occurs in nephrotic syndrome (NS) and may constitute a link between NS and vascular complications. Focal segmental glomerulosclerosis (FSGS) is a common cause of NS. This study aimed to assess endothelial markers at different stages of FSGS and define whether they were associated with thromboembolic complications and disease activity. Methods: Forty‐four patients with nephrotic‐range proteinuria and biopsy‐proven primary FSGS were included in this study. Nine of them had concurrent thromboembolisms. Thirty‐two sex‐ and age‐ matched healthy volunteers served as controls. Endothelial markers including circulating endothelial cells (CECs), soluble thrombomodulin (sTM), von Willebrand factor (vWf), soluble vascular cell adhesion molecule‐1 (sVCAM‐1) and sE‐selectin were assessed at the commencement of the study in all participants and were repeated at 2, 6 and 12 months of follow‐up in patients without thromboembolisms. Results: Patients with FSGS during active stage showed significantly higher levels of CECs, sTM, vWf, sVCAM‐1 and sE‐selectin when compared with controls. Moreover, patients with thromboembolisms had higher CECs and vWf than those without thromboembolisms. In patients without thromboembolisms, endothelial markers except sE‐selectin had inverse correlations with serum albumin and were positively related to cholesterol. Multiple analyses showed that cholesterol and serum albumin were independent predictors of CECs and sTM, and vWf and sVCAM‐1, respectively. At follow‐up, these markers systematically decreased as the disease went into remission, but the increase in vWf and sVCAM‐1 persisted even in patients obtaining complete remission for nearly a year. In patients with no response, levels of endothelial markers exhibited no obvious change. Conclusion: Patients with FSGS had elevated markers of endothelial dysfunction, which were largely related to the activity of the disease. Meanwhile, levels of CECs and vWf were higher in patients concurrent with thromboembolisms.     

Angiotensin-converting enzyme gene polymorphism and the progression rate of focal segmental glomerulosclerosis in Iranian children

Aim: Focal segmental glomerulosclerosis (FSGS) is one of the most common forms of glomerulonephritis leading to end-stage renal disease (ESRD). A few clinical and paraclinical factors are considered as contributing factors in progression rate. However, there are controversial reports on the relationship between ACE gene polymorphism and rapidity of progression of FSGS to ESRD in different populations. To elucidate this issue, we investigated the relationship between the insertion (I) and deletion (D) ACE gene polymorphism and rapidity of progression of FSGS to ESRD in Iranian children. Methods: Forty-one children aged 1–18 years admitted to St AlZahra Hospital, Isfahan, and St Ali Asghar Hospital, Tehran, Iran, with idiopathic FSGS were enrolled. Renal death was defined as a glomerular filtration rate (GFR) of less than 50 mL/min per 1.73 m² or a decreased GFR to less than 50% compare to baseline. Reaching renal death in less or more than 2 years were labelled as rapid progressors (RP) or slow progressors (SP), respectively. Intron 16 of the ACE gene was amplified by the polymerase chain reaction technique. Results: Twenty-eight patients were male and 13 were female. In 15 RP patients, the genotype distribution was 26.6% DD, 6.7% II and 66.7% ID. In 26 SP patients, the genotype was similar (38.6% DD, 7.6% II and 53.8% ID, P > 0.05). There were no statistically significant differences for ACE I/D gene polymorphism between the two groups of patients (P > 0.05). Conclusion: Our study revealed no correlation between ACE I/D gene polymorphism and rapidity of progression of FSGS to ESRD in Iranian children.     

A male patient with steroid-dependent nephrotic syndrome for 25 years and obesity-associated focal segmental glomerulosclerosis

An obese male patient with steroid-dependent nephrotic syndrome since age 6 years had a thirty-third relapse at the age of 29 years. Renal biopsy showed focal segmental glomerulosclerosis. Proteinuria disappeared after treatment with prednisolone. He went into complete remission and renal function remained normal at the age of 31 years. Focal segmental glomerulosclerosis associated with obesity was suspected. Long-term follow-up with renal biopsy is necessary in obese children with steroid-dependent nephrotic syndrome.     

A nephrotic case of vesicoureteral reflux representing focal segmental glomerulosclerosis associated with podocytic infolding lesions

The case was a 54-year-old woman who had suffered from occasional incontinence of urine after a craniotomy for subarachnoid hemorrhage in 1991. In June 1998 she was admitted for nephrotic syndrome without hematuria. Intravenous pyelography and voiding cystourethrography revealed bilateral hydronephrosis, atonic bladder, and vesicoureteral reflux (VUR). Renal biopsy demonstrated the presence of focal segmental glomerulosclerosis with cellular lesions. However, periodic-acid methenamine silver (PAM) staining revealed bubbling and spike appearance in the diffuse peripheral loops, although immunofluorescence microscopy showed negative findings in the glomeruli. Electron microscopy revealed diffuse thickening of the glomerular basement membrane (GBM) accompanying diffuse podocytic infolding lesions into the GBM and numerous spherical microstructures in the GBM. No findings of dense deposits were observed in the GBM and mesangium. Her urinary protein excretion decreased and renal function improved after placement of an urethral catheter for one year. A second renal biopsy revealed a remarkable decrease in podocytic infolding lesions, although microstructures in the GBM remained. Although mechanisms of the occurrence of these peculiar podocytic infolding lesions are unclear, it is speculated that podocyte damage due to hydronephrosis may have caused the lesions.     

Clinical features and long-term outcome of obesity-associated focal segmental glomerulosclerosis.

BACKGROUND: Several cases of obesity-associated focal segmental glomerulosclerosis (OB-FSG) have been reported but little is known about the clinico-pathological features of this entity and its long-term outcomes. METHODS: We studied 15 obese patients (BMI 35+/-5.2 kg/m(2)) with biopsy-proven FSG. They were compared with a control group of 15 non-obese patients with idiopathic FSG (I-FSG). RESULTS: Mean proteinuria at the time of renal biopsy was 3.1+/-2 g/24 h in OB-FSG; it reached the nephrotic range (> or =3.5 g/24 h) during follow-up in 12 patients (80%), but none of them had oedema, hypoproteinaemia, or hypoalbuminaemia. Proteinuria was more marked amongst I-FSG (6.5+/-4.2 g/24 h) and most of them developed oedema and biochemical nephrotic syndrome. Glomerulomegaly was observed in all renal biopsies from OB-FSG patients (mean glomerular diameter 256+/-24 microm in OB-FSG vs 199+/-26 microm in I-FSG, P<0.001). Twelve OB-FSG patients (80%) were treated with ACE inhibitors (ACEI) and proteinuria significantly decreased within the first 6 months of treatment but showed a later increase. None of the obese patients achieved a sustained weight loss. Seven (46%) patients with OB-FSG experienced a progressive renal insufficiency and five of them started intermittent dialysis. Kaplan-Meier estimated probabilities of renal survival after 5 and 10 years were 77 and 51%, respectively, in OB-FSG patients, and 52 and 30% in I-FSG (P<0.05). The risk of developing progressive renal failure among OB-FSG patients was statistically correlated with serum creatinine and creatinine clearance at presentation. CONCLUSIONS: OB-FSG indicates a poor prognosis with almost one-half of patients developing advanced renal failure. Knowledge of the clinico-pathological features of this entity (obesity, FSG lesions with glomerulomegaly, absence of nephrotic syndrome despite nephrotic-range proteinuria) should be helpful in establishing an accurate and early diagnosis.     

Angiotensin converting enzyme inhibition prevents development of collapsing focal segmental glomerulosclerosis in Thy-1.1 transgenic mice.

BACKGROUND: Thy-1.1 transgenic mice develop hypercellular focal and segmental glomerulosclerosis (FSGS) lesions that mimic human collapsing FSGS, in 7 days after injection with anti-Thy-1.1 antibodies. These lesions consist of proliferating parietal epithelial cells (PECs). We questioned whether the angiotensin converting enzyme inhibitor (ACE), captopril, could prevent the development of FSGS and if protection is related to the timing of drug administration. METHODS: First, we compared the effect of captopril treatment with angiotensin II-(ANGII) independent antihypertensive therapy (triple therapy). Second, we tested the effects of captopril administered over four different time intervals: days -7 to 0 (Ca-7>0), days -7 to 7 (Ca-7>7), days 0-7 (Ca0>7) and days 3-7 (Ca3>7) (day 0 being the day of injection of the antibody). RESULTS: In anti-Thy-1.1 injected control (C) mice we observed dedifferentiation and activation of podocytes, reflected by loss of ASD33 and increased expression of desmin, followed by a marked accumulation of PECs forming hypercellular lesions. PECs showed an increased expression of connective tissue growth factor (CTGF). Triple therapy or captorpil pre-treatment (Ca-7>0) had no significant effect on albuminuria or FSGS. In contrast, Ca0>7 and Ca3>7 treatment significantly lowered albuminuria and attenuated development of FSGS. The latter two treatments attenuated loss of ASD33 expression by podocytes but could not prevent increased desmin expression. In addition, these treatments reduced CTGF expression by PECs and prevented PEC proliferation. CONCLUSIONS: ACE inhibition, but not triple therapy, prevents the development of FSGS, suggesting an important role for ANGII. ACE inhibition has a protective effect even when started 3 days after the initial podocyte insult, which is probably related to the ability of ACE-inhibition to block PEC activation and proliferation.     

Combination of vasopressin and angiotensin inhibition in experimental focal glomerulosclerosis

Summary: This study was designed to investigate the role of vasopressin and angiotensin II in the pathogenesis of focal glomerulosclerosis (FGS). A non-peptide vasopressin VI antagonist (OPC-21268) and an angiotensin converting enzyme inhibitor (ACE-I) were administered either alone or in combination for 15 weeks to FGS, spontaneously hypercholesterolaemic rats. Treatment with the V1 antagonist (1% OPC-21268) suppressed the rise in systolic blood pressure (SBP), serum triglyceride (TG), blood urea nitrogen (BUN) and serum creatinine (S-Cr) levels, but not the elevations of urinary protein excretion (UPE) or serum total cholesterol (TC) levels. Morphologically, V1 antagonist significantly prevented an increase in the index of glomerular sclerosis (IS) and relative interstitial volume (RIV). In the low dose/high dose of V1 antagonist supplementation, the administration of 0.2% OPC-21268 failed to suppress any increase in the SBP and TG levels, but significantly preserved renal function and attenuated renal lesions. In the combination study, rats were divided into four groups: (i) V1 antagonist (1% OPC-21268); (ii) ACEI (imidapril, 5 mg/kg/per day); (iii) both treated groups; and (iv) an untreated control group. Angiotensin-converting enzyme inhibitor significantly suppressed increases in SBP, UPE, TC, BUN, and S-Cr levels compared with V1 antagonist. the combination therapy significantly enhanced these effects. Both agents significantly reduced IS and RIV, and combination therapy further reduced these levels. the results indicated that vasopressin, as well as angiotensin II, via the V1 receptor cause hypertension and renal injury in FGS rats. Vi antagonist and ACE-I have antihypertensive and renoprotective effects in this FGS model, and enhanced their beneficial effects when used as combination therapy.     

Recurrent nephrotic syndrome in a renal allograft recipient with focal and segmental glomerulosclerosis: Efficacy of plasmapheresis

Summary: We report a 29-year-old man with renal failure due to focal and segmental glomerulosclerosis (FSGS) who received a well-matched cadaveric renal allograft and had the early appearance of the nephrotic syndrome and renal insufficiency. His condition responded dramatically to plasmapheresis. the pathogenesis of FSGS recurring in a renal allograft may involve a recently identified circulating factor. the possible efficacy of plasmapheresis in the treatment of recurrent FSGS may be attributable to the removal of this factor.     

Poorly differentiated adenocarcinoma of the rectum in a nephrotic patient with focal segmental glomerulosclerosis

We report herein a case of poorly differentiated adenocarcinoma of the rectum occurring in a nephrotic patient with focal segmental glomerulosclerosis. The neoplasm which first appeared to be a submucosal tumor occurred in a 29-year old Japanese man with a neophrotic syndrome for 2 years and 6 months. Autopsy disclosed a large tumor located between the rectum and urinary bladder. Renal specimens showed changes consistent with focal segmental glomerulosclerosis.     

Treatment of focal and segmental glomerulosclerosis in adults with tacrolimus monotherapy.

BACKGROUND: Focal segmental glomerulosclerosis (FSGS) commonly presents with nephrotic syndrome (NS), and spontaneous remission is rare. NS is a poor prognostic marker for renal survival, and has serious extra-renal complications. Rapid remission using drugs with minimal side effects is desirable. Tacrolimus (Tac) has a more potent immunosuppressive effect and may be less toxic at therapeutic doses than ciclosporin (CsA). Although CsA has a role in the treatment of FSGS, there are limited data regarding the use of Tac monotherapy in this setting, and this is limited to experience in children. METHODS: We prospectively report the outcome for six adult patients with FSGS treated with Tac from first presentation with NS, and for a further five adult patients in remission on CsA converted to Tac in an attempt to arrest a progressive decline in renal function on CsA. RESULTS: All six patients treated with Tac from presentation with NS achieved remission after 6.5 +/- 5.9 months. The serum albumin for the group increased from 26.8 +/- 4.6 to 37.7 +/- 1.9 g/l (P = 0.003), and there was a significant reduction in the mean 24 h urinary protein excretion from 11.0 +/- 4.5 to 2.8 +/- 2.5 g (P = 0.003). All remissions were partial with a mean reduction in 24 h urinary protein of 75.2 +/- 16.8%. There was a non-significant reduction in MDRD GFR from 71.7 +/- 22.4 to 55.9 +/- 9.7 ml/min/1.73 m(2) (P = 0.07), which manifest within the first 3 months of Tac treatment but renal function was subsequently stable. The mean follow-up for the group was 12.8+/-5.5 months. Two of the five patients converted from CsA to Tac maintained complete remission, and the remaining three patients in partial remission had further reductions in proteinuria. There was an improvement in renal function concomitant with conversion to Tac in each case, with an overall improvement in MDRD GFR for the group of +1.9+/-1.1 ml/min/1.73 m(2)/month. CONCLUSIONS: Tac rapidly and effectively induced remission of NS in FSGS. Conversion from CsA to Tac indicates that Tac might be a more potent agent with less nephrotoxicity in this setting.     

Abrogation of nephrotic proteinuria by rituximab treatment in a renal transplant patient with relapsed focal segmental glomerulosclerosis

Relapse of focal segmental glomerulosclerosis (FSGS) after renal transplantation is 20-40%. Recurrence after a first relapse is 80%. The only current treatment is plasmapheresis and/or cyclophosphamide. We report successful treatment of a second relapse in a 48-year-old patient. At age 33, FSGS was diagnosed. The patient began hemodialysis 1 year later. In her first renal transplant, she developed recurrent FSGS and reached terminal transplant failure 3 years later. Eight years later, a second transplant was performed. Immunosuppressive regimen: steroids, mycophenolate mofetil (MMF), tacrolimus (TAC), and rabbit anti-thymocyte globulin. Proteinuria of 2-6 g/day was detected and a biopsy showed recurrent FSGS. Plasmapheresis was started without success. Another biopsy still showed FSGS. The patient received two doses of rituximab (375 mg/m2 each) i.v. Three weeks later, proteinuria was 350 mg/day (serum-creatinine 1.6 mg/dl). Twelve months later, proteinuria was at 90 mg/day. Rituximab might be an option for recurrent FSGS after renal transplantation.     

Recurrence of nephrotic syndrome/focal segmental glomerulosclerosis following renal transplantation in children

The incidence of recurrence of nephrotic syndrome/focal segmental glomerulosclerosis (NS/FSGS) is variable (~30%). The incidence of recurrence is less in African-Americans than in whites and Hispanics. Graft survival rates are decreased in recipients with FSGS, especially if remission of the NS is not achieved in those with recurrence. Although controversial, the use of living donor (LD) transplants are not contraindicated; however, obligatory heterozygote parental grafts with a podocin mutation should be used with caution. Optimal treatment to induce a remission post-transplant has not been delineated. Pre-transplant and/or prophylactic post-transplant pre-operative plasmapheresis (PP) for high-risk patients--especially those with recurrence in a previous graft--may be promising. An international multicenter controlled study is required to delineate the optimal approach to prevent and/or treat the recurrence of NS/FSGS.     

Nephrotic syndrome associated with focal segmental glomerulosclerosis in a patient with systemic lupus erythematosus and membranous glomerulonephritis in remission

Renal involvement is frequent in systemic lupus erythematosus (SLE). This lesion, termed lupus nephritis, has been reported clinically in at least 50% of the patients. It is generally assumed that in patients with SLE, renal abnormalities detected clinically are caused by lupus nephritis, especially lupus glomerulonephritis (GN). Thus, renal biopsy is performed not for diagnostic purposes, but rather for determining the type and extent of renal involvement. However, clinically significant renal abnormalities unrelated to lupus nephritis have rarely been described in patients with SLE. The reported case serves to emphasize this consideration. The patient was a 41-year-old woman who presented 11 years previously with severe hypertension, nephrotic syndrome, and a serum creatinine level of 2.9 mg/dL. Renal biopsy showed membranous GN and ischemic damage. After a prolonged remission induced by steroids and cyclophosphamide, the patient presented with nephrotic syndrome and a serum creatinine level of 2.1 mg/dL. Although she was normotensive at that time, there were features of SLE. Repeated renal biopsy showed focal segmental glomerulosclerosis without the changes of membranous GN or any type lupus GN. This case illustrates two interesting observations, ie, resolution of membranous GN and nonlupus renal lesions in patients with SLE.