Cystatin C as a Potential Blood Biomarker for Sarcoidosis: A Case Report.

Sarcoidosis is a multi-organ medical condition that is characterized by the formation of granulomas. We aimed to identify a correlation between each sarcoidosis blood biomarker and cystatin C (Cys-C) in sarcoidosis patients. We report a case of a 60-year-old man with sarcoidosis. The correlation between his Cys-C and each blood biomarker level and that between each blood biomarker and serum creatinine levels were determined using linear regression. Serum Cys-C correlated with each blood biomarker of sarcoidosis, while creatinine did not. These findings suggest that Cys-C is a potential blood biomarker for sarcoidosis.

Occurrence of fever in cell-free and concentrated ascites reinfusion therapy is not related to the primary disease or nature of ascites.

Cell-free and concentrated ascites reinfusion therapy (CART) is a treatment for refractory ascites wherein filtered and concentrated ascitic fluid is reinfused. Although fever is one of the side effects of CART, its cause is not clear. Patients who underwent at least one CART session between June 2011 and May 2021 at our medical center were retrospectively enrolled in the study. They were classified according to the primary disease and nature of ascites. Ninety patients were included in this study. Increase in body temperature (BT) after CART was observed, regardless of the primary disease and nature of ascites. The difference in temperature before and after CART did not differ based on the primary disease [cancerous (including hepatocellular carcinoma, ovarian cancer) and non-cancerous] and nature of ascites. Elevated BT and fever after CART are not related to the primary disease and nature of the ascites.

Utility of renal biopsy in differentiating idiopathic multicentric Castleman disease from IgG4-related disease.

Idiopathic multicentric Castleman disease (iMCD) is a subtype of human herpesvirus type 8 (HHV-8)-related Castleman disease that causes multi-organ damage, including kidney damage due to polyclonal lymphoproliferation and interleukin (IL)-6-induced cytokine storm. However, its renal pathological findings are unclear. We report the case of a woman in her 80 s who was diagnosed with iMCD based on renal pathological findings. Five years ago, hypergammaglobulinemia was detected, and her renal function declined. Renal biopsy revealed plasma cells infiltrating the stroma. Immunostaining revealed numerous IgG4-positive plasma cells. The serum IgG4 level was high, and she was initially diagnosed with IgG4-related disease (IgG4-RD) and treated with steroids. However, the therapeutic effect was poor. On re-examination, computed tomography revealed lymphadenopathy around the aorta and spleen. Renal histopathology showed numerous IL-6-positive plasma cells. Anemia and C-reactive protein (CRP) positivity persisted despite steroid administration. HHV-8 was negative, and polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes syndrome was not suspected. Thus, iMCD was diagnosed. Based on previous reports, there is no significant difference in IgG4 levels between iMCD and IgG4-RD, and IgG4-positive plasma cell infiltrates were observed in iMCD-affected organs. Therefore, it may be difficult to distinguish iMCD from IgG4-RD. In this case, high-serum IL-6 and CRP were observed, which are usually not seen in IgG4-RD but are common findings in iMCD, leading to the diagnosis. Patients with deep lymphadenopathy may be diagnosed with iMCD based on renal pathological findings. Renal biopsy is recommended for patients with suspected iMCD and decreased renal function.

IgA Nephropathy that Developed as an Immune-related Adverse Event of Pembrolizumab Complicated with Interstitial Nephritis.

A 70-year-old man received pembrolizumab as a second-line treatment for squamous cell lung cancer of the lower right lobe. After three courses, proteinuria and hematuria were observed, which worsened after seven courses. He was diagnosed with a combination of IgA nephropathy and active interstitial nephritis. Steroid pulse therapy was started, and the dose of prednisolone was gradually reduced from 60 mg/day. Renal dysfunction as an immune-related adverse event of pembrolizumab monotherapy for non-small cell lung cancer has been reported previously. Therefore, establishing a system for the early detection and treatment that distinguishes immune-related glomerular diseases is essential.

Detection of Autosomal Dominant Polycystic Kidney Disease by Medical Checkup at an Early Stage.

INTRODUCTION: Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited renal disease. Although abdominal echography during medical checkup may be effective for the early detection of ADPKD, there are no reports of the early detection of ADPKD during medical checkup. We investigated whether there was a difference in renal function and total kidney volume (TKV) at the time of diagnosis due to differences in diagnostic triggers for ADPKD. METHODS: A total of 34 patients diagnosed with ADPKD between January 1, 2010, and December 31, 2020, at the Department of Nephrology, Shimane University Hospital, were included. The triggers for diagnosis of the renal cyst(s) were usually unintentional findings. These included findings observed upon routine medical checkups, computed tomography, or abdominal echography during examination for other diseases (incidental detection group) and cases referred to our department for renal dysfunction (renal dysfunction group), and "other" group. We compared the renal dysfunction group and the incidental detection group. RESULTS: The estimated glomerular filtration rate (eGFR) at diagnosis was significantly higher in the incidental detection group. The TKV was significantly lower in the incidental detection group than in the other group. The number of patients with eGFR > 45 mL/min/1.73 m2, for which tolvaptan was safe and effective, was significantly higher in the incidental detection group than in the renal dysfunction group. CONCLUSION: Our study shows that medical checkup enables early detection of ADPKD. This is important because ADPKD may have serious complications. The present study did not examine the age at which abdominal echography screening for the early detection of ADPKD was more useful or cost-effective; thus, further research is needed to ascertain this.

[Investigation of the safety and usefulness of a renal biopsy for older elderly patients ≥75 years old].

AIM: We herein report the safety and usefulness of a kidney biopsy in older elderly patients (≥75 years old). METHODS: A retrospective observational study was conducted in older elderly patients who had received a renal biopsy at the Department of Nephrology, Shimane University Hospital, from January 1, 2008, to December 31, 2018. The native renal biopsy results of 52 later-stage elderly patients were analyzed (29 men and 23 women). RESULTS: The most common indication for a renal biopsy was nephrotic syndrome (n = 22), followed by rapidly progressive glomerulonephritis (n = 12) and asymptomatic urinary abnormalities (n = 12). The most common pathological diagnosis was membranous nephropathy (n = 12), followed by ANCA-associated nephritis (n= 8), minimal change nephrotic syndrome (6 case), membranoproliferative glomerulonephritis (n = 5), IgA nephropathy (n = 4), and diabetic nephropathy (n = 3). The concordance rate between the clinical and pathological diagnoses was 53.8%. The only complication of the renal biopsy was hemorrhaging requiring blood transfusion (1 patient; 1.9%). The hemoglobin level decreased by 0.5±0.05 d/dL after the biopsy. CONCLUSION: The rate of serious complications associated with a renal biopsy was comparable to that in previous reports in younger patient. Renal biopsies can therefore be safely performed even in older elderly patients. The concordance rate of the clinical and pathological diagnoses was about 50%. Therefore, renal biopsies should be performed in older elderly patients when necessary.

A Remarkable Elevation in the Procalcitonin Levels Due to Diabetic Ketoacidosis in a Hemodialysis Patient.

Procalcitonin (PCT), a marker of the inflammatory response during infections, can be elevated by diabetic ketoacidosis (DKA). A male patient in his 50s with diabetic nephropathy on hemodialysis presented with vomiting and a reduced level of consciousness and was diagnosed with DKA. His PCT level was markedly elevated, but bacterial cultures (blood, urine, and stool) were negative. The PCT level decreased after DKA improvement. In this patient, DKA probably enhanced the PCT levels. As DKA can increase the PCT levels, an elevation of the PCT levels in DKA patients may not be indicative of infectious diseases, and non-infectious causes of DKA should therefore be considered.

In vivo regeneration of interspecies chimeric kidneys using a nephron progenitor cell replacement system.

Kidney regeneration is expected to be a new alternative treatment to the currently limited treatments for chronic kidney disease. By transplanting exogeneous nephron progenitor cells (NPCs) into the metanephric mesenchyme of a xenogeneic foetus, we aimed to regenerate neo-kidneys that originate from transplanted NPCs. Previously, we generated a transgenic mouse model enabling drug-induced ablation of NPCs (the Six2-iDTR mouse). We demonstrated that eliminating existing native host NPCs allowed their 100% replacement with donor mouse or rat NPCs, which could generate neo-nephrons on a culture dish. To apply this method to humans in the future, we examined the possibility of the in vivo regeneration of nephrons between different species via NPC replacement. We injected NPCs-containing rat renal progenitor cells and diphtheria toxin below the renal capsule of E13.5 metanephroi (MNs) of Six2-iDTR mice; the injected MNs were then transplanted into recipient rats treated with immunosuppressants. Consequently, we successfully regenerated rat/mouse chimeric kidneys in recipient rats receiving the optimal immunosuppressive therapy. We revealed a functional connection between the neo-glomeruli and host vessels and proper neo-glomeruli filtration. In conclusion, we successfully regenerated interspecies kidneys in vivo that acquired a vascular system. This novel strategy may represent an effective method for human kidney regeneration.

Optimal route of diphtheria toxin administration to eliminate native nephron progenitor cells in vivo for kidney regeneration.

To address the lack of organs for transplantation, we previously developed a method for organ regeneration in which nephron progenitor cell (NPC) replacement is performed via the diphtheria toxin receptor (DTR) system. In transgenic mice with NPC-specific expression of DTR, NPCs were eliminated by DT and replaced with NPCs lacking the DTR with the ability to differentiate into nephrons. However, this method has only been verified in vitro. For applications to natural models, such as animal fetuses, it is necessary to determine the optimal administration route and dose of DT. In this study, two DT administration routes (intra-peritoneal and intra-amniotic injection) were evaluated in fetal mice. The fetus was delivered by caesarean section at E18.5, and the fetal mouse kidney and RNA expression were evaluated. Additionally, the effect of the DT dose (25, 5, 0.5, and 0.05 ng/fetus-body) was studied. Intra-amniotic injection of DT led to a reduction in kidney volume, loss of glomeruli, and decreased differentiation marker expression. The intra-peritoneal route was not sufficient for NPC elimination. By establishing that intra-amniotic injection is the optimal administration route for DT, these results will facilitate studies of kidney regeneration in vivo. In addition, this method might be useful for analysis of kidney development at various time points by deleting NPCs during development.