Yoshie Sasatomi

A multicenter cross-sectional study of circulating soluble urokinase receptor in Japanese patients with glomerular disease

Elevated serum-soluble urokinase receptor (suPAR) levels have been described in patients with focal segmental glomerulosclerosis (FSGS) in several different cohorts. However, it remains unclear whether this is the case for Japanese patients and whether circulating suPAR can be clinically useful as a diagnostic marker. To determine this, we measured serum suPAR levels in 69 Japanese patients with biopsy-proven glomerular diseases in a cross-sectional manner. The serum suPAR levels showed a significant inverse correlation with renal function by univariate (R(2) of 0.242) and multivariate (β=0.226) analyses. Even after excluding patients with renal dysfunction, no significant difference in the suPAR levels was detected among the groups. Receiver operating characteristic analysis and measures of the diagnostic test performance showed that suPAR was not a useful parameter for differentiating FSGS from the other glomerular diseases (AUC-ROC: 0.621), although a small subgroup analysis showed that patients with FSGS, treated with steroids and/or immunosuppressants, had significantly lower suPAR levels. Patients with ANCA-associated glomerulonephritis had significantly higher levels of suPAR compared with the other disease groups, which may be owing to their lower renal function and systemic inflammation. Thus, suPAR levels are significantly affected by renal function and have little diagnostic value even in patients with normal renal function.

Obesity Associated with Hypertension or Hyperlipidemia Accelerates Renal Damage

Obesity is known as a risk factor for nephropathy, especially nephrotic syndrome and focal segmental glomerulosclerosis, and can aggravate renal dysfunction. However, whether these changes are caused by obesity itself or by the associated hypertension (HT) and hyperlipidemia (HC) remains unclear at present. We investigated the influence of HT and HC in obesity on glomerular morphometry. The study included cases with obesity alone (O, body mass index more than 25 kg/m2, n = 16), O+HC (n = 8), O+HT (n = 17), HC (n = 10) alone, HT (n = 7) alone, and normal subjects (N, n = 11). Renal biopsies were examined and the glomerular diameter, and length and diameter of the glomerular capillary loop were determined using image analysis software. Clinically related data were obtained from medical records at the time of biopsy. Obesity was associated with dilatation of glomerular diameter due to glomerular loop elongation. However, end-stage renal disease (ESRD) was not noted in patients with obesity only. In contrast, ESRD requiring hemodialysis was noted in group O+HT within a 7.7-year follow-up period. Furthermore, enlargement of loop diameter was noted in group O+HC, but not in HC alone. These results suggest that obesity alone may not result in glomerular hyperfiltration or renal dysfunction, but obesity associated with hypertension or hyperlipidemia may accelerate renal damage.

Prognosis of renal amyloidosis: a clinicopathological study using cluster analysis.

Progression of renal amyloidosis is associated with severe proteinuria or nephrotic syndrome, and various mechanisms have been postulated to explain these complications. We studied the acceleration of proteinuria and reduced renal function by cluster analysis using clinical parameters, renal histological findings, type of renal amyloidosis and follow-up data. We divided 97 cases into three groups of renal amyloidosis. Accelerated progression correlated with serum creatinine (s-Cr) levels at renal biopsy and histological grade of renal damage by amyloid deposition (p < 0.0001). The most influential prognostic factors (s-Cr level ≧2.0 mg/dl) were tubulointerstitial and vascular damage induced by amyloid deposition at biopsy (odds ratio 96.9 and 69.2, respectively). In addition, we found amyloidosis type amyloid associated (AA) correlated with more amyloid-mediated vascular and tubulointerstitial damage than amyloidosis type amyloid light chain (AL) (p < 0.001, p < 0.01, respectively). Proteinuria and nephrotic syndrome were more severe in cases of amyloidosis AL than in amyloidosis AA (p = 0.076). In conclusion, less tubulointerstitial and vascular damage was caused by amyloid deposition; this was slowly progressive. Amyloid AA was detected in tubulointerstitial tissue and vessels more frequently than amyloid AL. Heavy proteinuria and/or nephrosis were not indicators of rapid progression.

Histopathological evidence of poor prognosis in patients with vesicoureteral reflux

Abstract Patients with vesicoureteral reflux (VUR) often develop reflux nephropathy with focal segmental glomerular sclerosis (FSGS), although the exact mechanisms leading to the development of this complication are unknown. To determine the early changes in glomeruli of VUR patients that ultimately cause poor renal outcome, we examined morphometrically renal biopsies of 16 young patients (age 10–20 years) with VUR at baseline pre-operatively. Patients were divided into two groups, those who subsequently showed good prognosis and those with poor renal prognosis at the end of a 10-year follow-up period. Patients with poor prognosis had worse proteinuria and lower creatinine at baseline than those with good prognosis. We also examined 40 age-matched control cases with previous temporal microhematuria and/or proteinuria but normal renal function and histology. Although the mean diameter of glomerular capillary did not change in VUR cases irrespective of prognosis, glomerular capillary length increased by 125% in cases with good prognosis, and 335% in cases with poor prognosis (P<0.01). Cystically expanded capillaries, with diameter ≥95% of that in age-matched control, were detected in five of eight patients with poor prognosis, but only in one of eight patients with good prognosis. In VUR, the number of podocytes/capillary diminished with increased length of the capillaries. Tuft adhesion to Bowman’s capsule and podocyte detachment were primarily found in patients with poor prognosis. Our results suggest that lengthening of glomerular capillaries in young patients with VUR is a compensatory reaction to hyperfiltration. The appearance of cystic capillary expansion, podocyte detachment and/or tuft adhesion to Bowman’s capsule in such glomeruli may be important indicators of renal prognosis in patients with VUR. These changes may lead to FSGS due to podocyte injury in patients with VUR, with subsequent deterioration of renal function.

The efficacy of incretin therapy in patients with type 2 diabetes undergoing hemodialysis

BackgroundAlthough incretin therapy is clinically available in patients with type 2 diabetes undergoing hemodialysis, no study has yet examined whether incretin therapy is capable of maintaining glycemic control in this group of patients when switched from insulin therapy. In this study, we examined the efficacy of incretin therapy in patients with insulin-treated type 2 diabetes undergoing hemodialysis.MethodsTen type 2 diabetic patients undergoing hemodialysis received daily 0.3 mg liraglutide, 50 mg vildagliptin, and 6.25 mg alogliptin switched from insulin therapy on both the day of hemodialysis and the non-hemodialysis day. Blood glucose level was monitored by continuous glucose monitoring. After blood glucose control by insulin, patients were treated with three types of incretin therapy in a randomized crossover manner, with continuous glucose monitoring performed for each treatment.ResultsDuring treatment with incretin therapies, severe hyperglycemia and ketosis were not observed in any patients. Maximum blood glucose and mean blood glucose on the day of hemodialysis were significantly lower after treatment with liraglutide compared with treatment with alogliptin (p < 0.05), but not with vildagliptin. The standard deviation value, a marker of glucose fluctuation, on the non-hemodialysis day was significantly lower after treatment with liraglutide compared with treatment with insulin and alogliptin (p < 0.05), but not with vildagliptin. Furthermore, the duration of hyperglycemia was significantly shorter after treatment with liraglutide on both the hemodialysis and non-hemodialysis days compared with treatment with alogliptin (p < 0.05), but not with vildagliptin.ConclusionsThe data presented here suggest that patients with type 2 diabetes undergoing hemodialysis and insulin therapy could be treated with incretin therapy in some cases.

Evidence-based clinical practice guidelines for nephrotic syndrome 2014

Nephrotic syndrome is a clinical syndrome showing specific features of heavy proteinuria and hypoalbuminemia or hypoproteinemia as its consequence. It is caused by increased permeability of serum protein through the damaged basement membrane in the renal glomerulus. The definition of nephrotic syndrome includes both massive proteinuria (≥3.5 g/day) and hypoalbuminemia (serum albumin ≤3.0 g/dL) (Tables 1, 4). Primary nephrotic syndrome has no background diseases, whereas secondary nephrotic syndrome has any background diseases. As a result of massive proteinuria and hypoalbuminemia, this syndrome is frequently accompanied by edema, dyslipidemia, abnormalities in coagulation/fibrinolysis, reduced renal function, and immunological disorders. The effect of treatment is determined by the urinary protein level after treatment (Tables 2, 3). Table 1 Clinical definition of adult nephrotic syndrome 1. Proteinuria: ≥3.5 g/day and continuous (comparable to ≥3.5 g/gCr at spot urine) 2. Hypoalbuminemia: Serum albumin ≤ 3.0 g/dL Serum total protein ≤ 6.0 g/dL is helpful 3. Edema 4. Dyslipidemia (Hyper LDL cholesterolemia) The above urine protein and hypoalbuminemia are indispensable prerequisites for the clinical diagnosis of nephrotic syndrome Edema is not an indispensable prerequisite but an important finding for nephrotic syndrome Dyslipidemia is not an indispensable prerequisite for nephrotic syndrome Oval fat body is helpful for diagnosis of nephrotic syndrome Table 2 Therapeutic evaluation for nephrotic syndrome The therapeutic evaluation is done by the amount of urine protein at 1 and 6 months after the initiation of treatment Complete remission: urine protein <3.0 g/day Incomplete remission I: 0.3 g/day ≤ urine protein <1.0 g/day Incomplete remission II: 1.0 g/day ≤ urine protein <3.5 g/day Non-response: urine protein ≥3.5 g/day The diagnosis of nephrotic syndrome and therapeutic evaluation should be done by 24-hour urine collection. If to collect 24-hour urine is impossible, the ratio of urine protein and urine creatinine (g/gCr) at spot urine is available for the diagnosis of nephrotic syndrome and therapeutic evaluation In principle, the evaluation of complete remission or incomplete remission at 6 months after the initiation of treatment includes the improvement of clinical finings and serum albumin The evaluation of relapse is the condition that urine protein ≥ 1 g/gCr (1g/gCr) runs or ≥(2+) continues 2–3 times in a row In Europe and the United States partial remission defines 50% or more of the reduction of urine protein, while the Japanese evaluation does not use this definition Table 3 The classification by the response to treatment of nephrotic syndrome Steroid resistant nephrotic syndrome: The enough dose of steroid treatment fails to achieve complete remission or incomplete remission I at 1 month after the initiation of treatment Refractory nephrotic syndrome: The various treatments including steroid and immunosuppressive agents fail to achieve complete remission or incomplete remission I at 6 months after the initiation of treatment Steroid dependent nephrotic syndrome: Steroid treatment is impossible to discontinue, because repeated over 2 times relapses appear after the reduction or discontinuation of steroid Frequent relapse nephrotic syndrome: Over 2 times relapses appear in 6 months Nephrotic syndrome requiring chronic treatment: Nephrotic syndrome to be treated by steroid or immunosuppressive agents over 2 years Table 4 The definition of nephrotic syndrome in children 1. Nephrotic syndrome: Massive proteinuria (40 ≥ mg/h/m2) + hypoalbuminemia (serum albumin ≤ 2.5 g/dL) 2. Steroid sensitive nephrotic syndrome: Daily administrated prednisolone treatment attains the remission within 4 weeks 3. Relapse: After the remission urine protein of 40 ≥ mg/h/m2 or morning urine 100 mg/dL or more by dip stick continues for 3 days

Various Roles of Th Cytokine mRNA Expression in Different Forms of Glomerulonephritis

Background: Kidney disease is characterized by injurious immune responses to self or foreign antigens. The development and maintenance of immune responses generally involves activation of T lymphocytes. We evaluated mRNA expression patterns of T-cell cytokines to identify the principal Th-cell subset involved in the development of antineutrophil cytoplasmic antigen-associated pauci-immune crescentic glomerulonephritis (ANCAGN), membranoproliferative glomerulonephritis (MPGN), and membranous nephropathy (MN). Methods: Kidney biopsy specimens from ANCAGN (17), MPGN (11), and MN (14) patients were evaluated for mRNA expression of various T-cell cytokines. Results: Interferon-γ mRNA expression was detected in both ANCAGN and MPGN, but not in MN patients. Furthermore, mRNA expression of interleukin (IL)-12, a Th1-associated cytokine, was lower in MN patients than in ANCAGN and MPGN patients. In contrast, a significantly higher expression of IL-4 and IL-5 was observed in MN than in ANCAGN and MPGN patients. In the analyses of Th17-associated cytokine expression, a significantly higher expression of IL-6 and IL-17 was observed in ANCAGN than in MPGN and MN patients. No significant differences were observed in the expression of these cytokines between MPGN and MN patients. With regard to Treg-associated cytokines, a significantly higher IL-10 expression was observed in MN than in ANCAGN patients, and a significantly higher transforming growth factor-β expression was observed in MN than in ANCAGN and MPGN patients. Similarly, Foxp3 expression was significantly higher in MN. Conclusion: Th1 and Th17 immune responses in ANCAGN, the Th1 response in MPGN, and Th2 and Treg responses in MN patients may be integral for the distinct histological features of these diseases.

Possible Involvement of Altered RGD Sequence in Reduced Adhesive and Spreading Activities of Advanced Glycation End Product-Modified Fibronectin to Vascular Smooth Muscle Cells

Although fibronectin (FN) modified by advanced glycation end products (AGEs) has been shown to contribute to the development of diabetic vascular complications through its reduced adhesive activity to vascular cells, little is known about changes in the cell binding domain of AGE-modified FN. Here we examined the mechanism of reduced adhesive and spreading activities of AGE-modified FN to vascular smooth muscle cells (SMCs), particularly the contribution of modification of Arg-Gly-Asp (RGD) sequence. Incubation with glucose caused not only the formation of N-carboxymethyllysine and pentosidine, but also polymerization of FN in a dose- and time-dependent manner. AGE-modified FN had significantly low adhesive and spreading activities to cultured SMCs. On the other hand, multimeric FN formed by disulfide bonds did not show any effect on either cell adhesion or spreading. The adhesive activity of type I collagen, one of the RGD sequence-containing proteins, to SMCs also decreased by AGE-modification. The inhibitory effect of AGE-modification on cell adhesion was significantly greater in type I collagen than in FN. Although the extent of AGE-modification of type I collagen was indistinguishable from that of FN, AGE-modification decreased the arginine content of type I collagen by 69.5% and of FN by 30.6%, compared with their non-glycated forms. The addition of RGD peptides caused a decrease in adhesion of SMCs to non-glycated FN, but not to AGE-modified FN. Modification of RGD sequence with glyoxal eliminated its inhibitory effect on cell adhesion. Our results suggest that a marked decrease in adhesive and spreading activities of AGE-modified FN to SMCs might largely be due to a modification of its RGD sequence by AGE, thus suggesting a potential link between AGE modification of FN and the pathogenesis of diabetic angiopathy.

Macrophage subclasses and proliferation in childhood IgA glomerulonephritis

We immunohistologically compared the number of intraglomerular infiltrating cells in 14 children with poststreptococcal acute glomerulonephritis (PSAGN) and 20 children with immunoglobulin A glomerulonephritis (IgAGN) with histological characteristics similar to those of PSAGN to explain the difference in clinicopathological characteristics between these two diseases. Immunohistological study was performed in kidney tissues from these patients by using monoclonal antibodies of T-cell marker (CD3 and CD45RO), B-cell marker (CD20), neutrophil marker (CD15), macrophage marker (CD68), four subclasses of macrophages (early-stage, acute-stage, chronic-stage, and mature inflammatory macrophage marker), and proliferating cell nuclear antigen (PCNA). The 34 patients were classified into three stages according to the time from the detection of urinary abnormalities to biopsy. Intraglomerular immunopositive cells were expressed as the number of cells per glomerulus. There were more intraglomerular positive cells of CD15, CD68, and the four macrophage subclasses in PSAGN than IgAGN. The number of intraglomerular infiltrating macrophages decreased with time in PSAGN, whereas the number of macrophages in IgAGN remained constant at all stages. Intraglomerular infiltration of acute-stage inflammatory macrophages alone was evident in IgAGN. Both the number of intraglomerular proliferating macrophages (PCNA-positive plus CD68-positive cells) and proportion of proliferating macrophages/total macrophages were greater in IgAGN than PSAGN. Normal urinalysis results were evident in all patients with PSAGN during follow-up, and urinary abnormalities persisted in 18 patients with IgAGN. In conclusion, differences in the maturity of infiltrating macrophages and number of proliferating macrophages are associated with the different clinicopathological characteristics in children with PSAGN and IgAGN.

Macrophage impairment produced by Fc receptor gamma deficiency plays a principal role in the development of lipoprotein glomerulopathy in concert with apoE abnormalities

BACKGROUND To obtain a clear understanding of the pathogenesis of lipoprotein glomerulopathy (LPG), we studied the role of the deficiency of Fc receptor gamma chain (FcRγ) for the development of LPG in concert with apolipoprotein E (apoE) abnormalities. METHODS We generated apoE and FcRγ double-knockout (FcRγ/apoE-KO) mice, and subsequently introduced several kinds of human recombinant apoE genes. At 21 days after infection, the mice were sacrificed and histologically examined. Peritoneal macrophages were evaluated for their response to modified lipids. RESULTS In the FcRγ/apoE-KO mice, the human apoE3-injected mice showed the most drastic LPG-like changes, as well as prominent hypertriglyceridemia. Meanwhile, relative to the human apoE3-injected mice, the FcRγ/apoE-KO mice showed greater lipoprotein deposition and less macrophage infiltration into the mesangial area. Moreover, the peritoneal macrophages in the apoE/FcRγ-KO mice were impaired in lipid uptake and secretion of the cytokines monocyte chemotactic protein-1 and regulated upon activation, normal T-cell expressed and secreted, after the uptake of oxidized low-density lipoprotein. CONCLUSIONS These results suggest that the impairment of macrophage function resulting from FcRγ deficiency plays a principal role in the development of LPG in the presence of apoE abnormalities.