High molecular weight adiponectin inhibits vascular calcification in renal allograft recipients.

BACKGROUND: Adiponectin (ADPN) prevents the development/recurrence of cardiovascular events via its anti-atherogenic effects. However, few long-term studies have examined the changes in serum ADPN levels and arterial calcification seen in renal allograft recipients. SUBJECTS AND METHODS: The effects of the serum ADPN level on arterial calcification were examined in 51 Japanese renal allograft recipients. Abdominal aorta calcification was evaluated on computed tomography using the aortic calcification area index (ACAI). The change in the ACAI and serum high-molecular-weight (HMW)-ADPN fractions were studied over an 8-year period. The arterial expression of ADPN, ADPN receptors (AdipoR)1 and 2, and T-cadherin (cadherin-13) were also examined by immunohistochemistry. RESULTS: The change in the ACAI were grouped into quartiles and compared with the alterations in the serum levels of each ADPN fraction over an 8-year period. The change in the ACAI was much lower in the patients with highly elevated HMW-ADPN levels.Multiple regression analysis demonstrated that an advanced age at transplant and a history of cardiovascular complications were associated with an increased change in the ACAI, while higher HMW-ADPN concentrations were associated with improvements in the ACAI. Serum HDL-C level was also identified as a positive factor to increase serum HMW-ADPN level.In immunohistochemical examinations, ADPN was detected on CD31-positive arterial endothelial cells from renal allograft biopsy samples. ADPN co-localized with T-cadherin and AdipoR1, but only partially co-localized with AdipoR2. CONCLUSION: Both HMW-ADPN and HDL-C might inhibit the progression of vascular calcification by promoting ADPN binding to vascular endothelial cells via T-cadherin and AdipoR in Japanese renal allograft recipients.

Circulating and renal expression of HLA-G prevented chronic renal allograft dysfunction in Japanese recipients.

BACKGROUND: Although the risk of acute rejection has been studied in renal transplanted patients, there is little data about the long-term renal survival effects of non-classical human leukocyte antigen class I (HLA-G) in Japanese patients. METHOD: We investigated the changes in the estimated glomerular filtration rate (eGFR) for Japanese, and factors affecting the eGFR in 141 adult Japanese subjects whose allografts had survived for at least 1 year. Clinical background data, gender, HLA matching status, the total ischemic time, ABO incompatibility, immunosuppressive therapy, and the serum soluble(s) HLA-G5 level were examined. In addition, renal biopsy specimens from 32 cases, which were obtained before, or 2-4 weeks or one year after the transplant were also evaluated for HLA-G1/5 expression using monoclonal anti-HLA-G antibodies (clone 87G or 4H84). RESULTS: The rates of change per year in the median eGFR (ΔeGFR) and sHLA-G5 were -1.5 ml/min/1.73 m2/year and 11.8 ng/ml, respectively. A positive correlation was detected between the ΔeGFR and sHLA-G5 (r = 0.188, p = 0.025). In multivariate regression analysis, sHLA-G5 and HLA-matching were significant predictors of an improvement in eGFR (beta for sHLA-G: 0.374, p = 0.009; beta for mismatching: -1.135, p = 0.045). The renal tubular epithelial cells (TEC) in 11 cases showed a perinuclear HLA-G1/5 expression after renal transplantation. The renal HLA-G1/5-positive patients displayed much better ΔeGFR (p < 0.05). In conclusion, the sHLA-G5 level and HLA matching status are independent predictors of renal allograft function, as determined by the ΔeGFR, in Japanese patients. HLA-G1/5 was also detected on TEC in the patients with favorable renal function.

The long-term outcomes of hepatitis C virus core antigen-positive Japanese renal allograft recipients.

BACKGROUND: The impact of hepatitis C virus (HCV) infections on patient long-term survival after renal transplants is unclear. METHOD: To clarify the long-term outcomes of Japanese renal allograft recipients with HCV infections, we studied the cases of 187 patients (118 males and 69 females; 155 living donor cases, and 32 deceased donor cases; median follow-up period: 250 months) who underwent an initial renal transplant at Kanazawa Medical University from 1974 onwards. RESULT: In this cohort, 35 patients (18.7%) were HCV core antigen (Ag)-positive, and 13 of them (37.1%) died (due to liver cirrhosis (4 cases), hepatocellular carcinoma (1 case), fibrosing cholestatic hepatitis due to HCV (1 case), and infections complicated with chronic hepatitis (6 cases)). However, only 14 of the 145 (9.7%) recipients died in the HCV-Ag/HCV antibody (Ab)-negative group. The Kaplan-Meier life table method indicated that the HCV-infected group exhibited significantly lower patient and death-censored allograft survival rates (log-rank test; patient survival: Chi-square: 11.2, p = 0.004; graft survival: Chi-square: 25.7, p < 0.001). The survival rate of the HCV-Ag-positive recipients decreased rapidly at 240 months after the renal transplant procedure. In addition, a Cox proportional hazards model indicated that positivity for the HCV-Ag was the most important independent risk factor for post-renal transplant survival and allograft function [survival: hazard ratio (HR) 3.93 (1.54-10.03), p = 0.004; graft function: HR 2.09 (1.14-3.81), p = 0.016]. CONCLUSION: HCV infection is a harmful risk factor for patient survival (especially at ≥20 years post-renal transplant) and renal allograft function in allograft recipients.

Regulation of soluble Flt-1 (VEGFR-1) production by hnRNP D and protein arginine methylation.

Soluble fms-like tyrosine kinase-1 (sFlt-1) functions as a potent inhibitor of angiogenesis by trapping vascular endothelial growth factor (VEGF). However, the precise regulatory mechanism of sFlt-1 production is unknown. Here, we report that vascular sFlt-1 production is regulated by heterogeneous nuclear ribonucleoprotein D (hnRNP D) and arginine methylation. We showed that hnRNP D bound to Flt-1 pre-mRNA and that hnRNP D overexpression decreased sFlt-1 mRNA in human microvascular endothelial cells (HMVECs). In contrast, the reduction of hnRNP D levels induced an increase in sFlt-1 production. Overexpression of an hnRNP D mutant in which the arginine residue of the known arginine methylation motif (arginine-glycine-glycine; RGG) was replaced with alanine did not reduce the level of soluble-form RNA produced from the Flt-1 minigene. Moreover, we demonstrated that overexpression of arginine methyltransferase decreased the soluble-form RNA level, whereas overexpression of arginine demethylase and addition of methyltransferase inhibitors increased sFlt-1 mRNA levels. These findings indicate that hnRNP D and arginine methylation play important roles in the regulation of Flt-1 mRNA alternative polyadenylation.

A case of IgG4-related kidney disease complicated by eosinophilic lung disease.

IgG4-related disease is a systemic chronic inflammatory disorder characterized by a high blood level of IgG4 and the organ injuries by marked infiltration of IgG4-positive plasma cells and fibrosis. A 71-year-old male was hospitalized for a cough, malaise and anorexia. IgG4-related disease was suspected due to marked elevation of the serum IgG4 level. However, on lung biopsy, only eosinophil infiltration was demonstrated with no plasma cell infiltration. Otherwise abdominal contrast-enhanced CT showed mild enlargement of the bilateral kidneys and many differed contrasted areas and FDG PET-CT. Moreover, renal biopsy specimens showed typical tubulointerstitial nephritis with a large number of IgG4-positive plasma cells infiltration (the IgG4/IgG-positive cell rate, 89 %) and fibrosis. We diagnosed this patient as typical IgG4-related kidney disease. He was treated by the moderate dose of prednisolone (0.8 mg/kg/day) alone, and showed prompt response in the clinical condition, and both the lung and kidney lesions. In this case, it was useful for diagnosis of IgG4-related diseases to evaluate an image such as abdominal contrast-enhanced CT and FDG PET-CT. Our case might be one of the possible patterns of IgG4-related lung diseases. In addition, we thought that there might be an association between hypereosinophilia and IgG4-related kidney disease.

Clinicopathological characteristics of M-type phospholipase A2 receptor (PLA2R)-related membranous nephropathy in Japanese.

BACKGROUND: Recent studies have suggested that assessments of serum antibodies against M-type phospholipase A2 receptor (PLA2R) and the glomerular expression of PLA2R antigen in biopsy specimens are useful for the diagnosis of primary membranous nephropathy (MN). In this study, we assessed both of them and investigated the clinicopathological characteristics of PLA2R-related Japanese MN. METHODS: We retrospectively enrolled 22 primary and 3 secondary Japanese patients whose serum samples and renal specimens were collected before treatment. According to the findings of serum antibodies and antigen in glomeruli, the primary MN patients were classified into PLA2R-related or -unrelated MN. We compared their clinicopathological findings, including IgG subclass staining, and electron microscopic findings, and evaluated the predictors of proteinuria remission. RESULTS: In primary MN, 16 patients (73 %) were classified into the PLA2R-related group, and 6 patients into the PLA2R-unrelated group. There was no significant difference in baseline laboratory data and electron microscopic findings, except for eGFR and serum IgG levels. IgG4-dominant deposition was more common in the related group (63 vs. 0 %). The 10 PLA2R-related patients with dominant IgG4 deposition had a lower rate and prolonged time in remission compared with the 6 PLA2R-related patients with non-dominant IgG4 (log-rank, p = 0.032). Furthermore, dominant IgG4 deposition was an unfavorable predictor of remission by multivariable Cox proportional hazard analysis. CONCLUSIONS: Assessments of both serum PLA2R antibodies and PLA2R antigen in glomeruli were more sensitive for the diagnosis of PLA2R-related MN, and among affected Japanese patients, those with dominant IgG4 deposition had worse clinical outcomes.

A patient with persistent renal AL amyloid deposition after clinical remission by HDM/SCT therapy.

A 62-year-old female patient was admitted to our hospital for evaluation of nephrotic syndrome. Monoclonal gammopathy (IgG λ type) and urinary Bence Jones proteins were detected in the serum and urine by the immunofixation method. The initial renal biopsy revealed amyloid deposition in mesangial area, glomerular capillary walls and arterioles by Congo-red staining, and amyloid fibers were detected by electron microscopy. On the bone marrow test, plasma cells accounted for 8.6%. Based on these findings, we diagnosed as AL amyloidosis associated with multiple myeloma. We treated her by high-dose intravenous injection therapy of melphalan combined with autologous peripheral blood stem cell transplantation. She achieved complete hematologic response 27 months later, however. Urine M-protein disappeared 2 months after treatment, and proteinuria slowly disappeared 17 months after treatment. On the other hand, amyloid fibers remained in renal biopsied tissues at 17 and 53 months after therapy. Electron microscopic examination also revealed the similar amyloid fibers in glomeruli. These findings suggest that, in this case, immunoglobulin light chains may cause directly and/or indirectly glomerular epithelial injury and nephrotic range proteinuria rather than via amyloid fiber formation.

A case of second renal transplantation with acute antibody-mediated rejection complicated with BK virus nephropathy.

We reported a 40-year-old female case of second renal transplantation with antibody-mediated rejection (AMR) complicated by BK virus nephropathy. She started hemodialysis (HD) at the age of 17 because of IgA nephropathy. At the age of 18, she underwent living-donor kidney transplantation from her father, but two and a half years after transplantation, she developed chronic rejection. This time, she received cadaveric renal transplantation under the negative cross-match (AHG-LCT), and HLA-AB 1 mismatch and -DR 1 mismatch. Immunosuppressive therapy was initiated using the following four immunosuppressants: methylprednisolone, mycophenolate mofetil, cyclosporine, and basiliximab. However, renal graft showed delayed function, the biopsy showed glomerulitis (g2), endarteritis (v1), and cellular infiltration (ptc3) consisting mainly of mononuclear cells in the peritubular capillary with diffusely positive C4d and anti-SV 40 large T-antigen-positive renal tubular epithelial cells on post-operative day 19. The donor-specific antibody for HLA-B46 was proven by the LAB screen method. We performed plasma exchange three times and administered immunoglobulin (15 g in total). Then, methylprednisolone pulse therapy was added, and the serum creatinine (SCr) levels gradually decreased. On post-operative day 44, the patient was removed from HD and was discharged with SCr level of 3.3 mg/dL.

A case report of an adult with severe hyperlipidemia during acute lymphocytic leukemia induction therapy successfully treated with plasmapheresis.

Plasmapheresis for the treatment of hypertriglyceridemia has previously been performed in patients with sudden onset severe hypertriglyceridemia and acute pancreatitis; however, only a few reports of this procedure have been published. We report here on a case showing severe hypertriglyceridemia during asparaginase (Asp) treatment for acute lymphocytic leukemia (ALL), and give an overview of a lipid-lowering apheresis therapy. To prevent the complication of pancreatitis due to hypertriglyceridemia, we performed plasma exchange (PE) three times using fresh frozen plasma. PE remarkably reduced both serum triglyceride and total cholesterol levels from 5430 mg/dL to 403 mg/dL and from 623 mg/dL to 204 mg/dL, respectively. The causes of severe hyperlipidemia in this patient were considered to include: the Asp treatment for ALL, and a genetic background with a heterozygote of familial lipoprotein lipase (LPL) defect syndrome, because the patient's plasma LPL level after intravenous heparin injection was low at 137 ng/mL. Hence, PE using fresh frozen plasma may be useful not only to remove lipoproteins, but also to supply defective factors, such as LPL, in similar cases.

Detection of serum hepcidin in renal failure and inflammation by using ProteinChip System.

Hepcidin, a key regulator of iron metabolism, is expressed in the liver, distributed in blood, and excreted in urine. However, to date, no reliable and practical method for measuring the bioactive form of hepcidin in serum has been developed. Here, we used surface-enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF MS) to analyze the distinctive serum proteomic patterns of patients receiving hemodialysis. In the range of 1000 to 15,000 m/z, we found 3 peptides at 2192, 2789, and 2851 m/z that showed a significant correlation with the serum ferritin levels. The molecular sizes of peptides at 2192 and 2789 m/z matched with the reported sizes of hepcidin-20 and -25, respectively, and the serum peptide at 2789 m/z was identified as hepcidin-25 by collision-induced dissociation tandem MS. By using SELDI-TOF MS, we developed a semiquantitative assay for hepcidin-25. In this assay, the level of serum hepcidin-25 correlated well with levels of serum ferritin and serum interleukin-6. Hepcidin-25 was found to accumulate in the serum of patients receiving hemodialysis; this could contribute to the pathogenesis of renal anemia by decreasing the available iron for hematopoiesis. Thus, SELDI-TOF MS would be a clinically useful tool to detect and semiquantify bioactive hepcidin in serum.