Kidney Veno-Muscular Characteristics and Kidney Disease Progression: A Native Kidney-Biopsy Study.

Rationale & Objective: Assessment of kidney biopsies provides crucial information for diagnosis and disease activity, as well as prognostic value. Kidney-biopsy specimens occasionally contain veno-muscular complex (VMC), which consists of muscle tissues around the kidney venous system in the corticomedullary region. However, the role of VMC and the clinical significance of VMC variants are poorly understood. In the present study, we investigated kidney prognostic values of VMC variants. Study Design: Retrospective cohort study. Setting & Participants: Among 808 patients who underwent a kidney biopsy from 2011 to 2019, 246 patients whose kidney biopsy specimens contained VMC were enrolled. Predictors: VMC variants; inflammatory-VMC (an infiltration of ≥80 inflammatory cells/mm2-VMC area) and VMC hypertrophy (hyper-VMC, a VMC average width ≥850 µm), and the interstitial fibrosis/tubular atrophy (IFTA) score. Outcomes: A decline in estimated glomerular filtration rate (eGFR) ≥40% from the baseline or commencement of kidney replacement therapy. Analytical Approach: Cox proportional hazards model. Results: Among 246 patients with data on VMC, mean baseline eGFR was 56.0±25.6 ml/min per 1.73 m2; 80 had high inflammatory-VMC, and 62 had VMC hypertrophy. There were 51 kidney events over median follow-up of 2.5 years. We analyzed 2 VMC variants. Multivariable logistic regression analysis revealed that eGFR negatively correlated with the presence of both inflammatory-VMC and hyper-VMC. A Cox proportional hazards analysis revealed that inflammatory-VMC (but not hyper-VMC) was independently associated with the primary outcome after adjustments for known risk factors of progression, including proteinuria, eGFR, and the interstitial fibrosis/tubular atrophy (IFTA) score (hazard ratio, 1.97; 95% confidence interval, 1.00-3.91). Limitations: Single-center study and small sample size. Conclusions: Assessment of inflammatory-VMC provides additional kidney prognostic information to known indicators of kidney disease progression in patients who undergo kidney biopsy. Plain-Language Summary: Assessment of kidney biopsies provides crucial information for diagnosis, disease activity, and prognostic value. Kidney-biopsy specimens occasionally contain veno-muscular complex (VMC), which consists of muscle tissues around the kidney venous system. Currently, the role of VMC in kidney health and diseases and the clinical significance of VMC variants are poorly understood. In the present study, we have shown that an infiltration of ≥80 inflammatory cells/mm2-VMC area (inflammatory-VMC) is independently associated with kidney disease progression after adjustments for known risk factors of progression. Therefore, assessment of inflammatory-VMC provides additional kidney prognostic information to known indicators of kidney disease progression in patients who undergo kidney biopsy.

Preventive effect of culture supernatant of epithelial-like peritoneal mesothelial cells on peritoneal fibrosis.

Peritoneal fibrosis (PF) is a primary reason for discontinuing peritoneal dialysis, which involves characteristic changes of peritoneal mesothelial cells (PMCs). We previously reported preventive effects of implanting human epithelial-like PMCs (P-Epi) for mouse PF caused by mechanical peritoneum scrapings. In the present study, we analysed the preventive effects of culture supernatant of P-Epi in PF. Concentrated culture supernatant of P-Epi or human fibroblast-like PMCs (P-Fibro) or vehicles was injected into nude mice that had undergone mechanical scraping of the parietal and visceral peritoneum, and thickness and amount of adhesions were analysed. Although increased peritoneal adhesions and peritoneum thickening were observed in the vehicle-injected positive control group compared to the sham operation group, fewer number of adhesions and less thickness were observed in the mice treated with culture supernatant of P-Epi, but not P-Fibro, compared to the vehicle-injected positive controls. Immunofluorescent analysis revealed that the expression of extracellular matrix, type I collagen and fibronectin, was lower in the mice treated with culture supernatant of P-Epi than in the vehicle-injected positive controls. In addition, exosomes from P-Epi significantly reduced transforming growth factor-ß (TGF-ß)-induced expressions of type I collagen and fibronectin in 3T3 fibroblast cells. Collectively, culture supernatant of P-Epi has preventive effects on PF, thus cell therapy is not necessarily required. Further exploration of substances secreted by P-Epi and their protective mechanisms could lead to the development of therapeutic strategies to limit PF.

Association between Urinary Creatinine Excretion and Hypothyroidism in Patients with Chronic Kidney Disease.

While hypothyroidism increases serum creatinine (Cr) levels, it is uncertain whether the elevation is mediated via a decline in the glomerular filtration rate (GFR) or the reflection of enhanced Cr production from the muscles or both. In the present study, we explored an association between urinary Cr excretion rate (CER) and hypothyroidism. A total of 553 patients with chronic kidney disease were enrolled in a cross-sectional study. Multiple linear regression analysis was performed to explore the association between hypothyroidism and urinary CER. The mean urinary CER was 1.01 ± 0.38 g/day and 121 patients (22%) had hypothyroidism. The multiple linear regression analysis revealed explanatory variables with urinary CER, including age, sex, body mass index, 24 h Cr clearance (24hrCcr), and albumin while hypothyroidism was not considered an independent explanatory variable. In addition, scatter plot analysis with regression fit line representing the association between estimated GFR calculated using s-Cr (eGFRcre) and 24hrCcr revealed that eGFRcre and 24hrCcr had strong correlations with each other in hypothyroid patients as well as euthyroid patients. Collectively, hypothyroidism was not considered an independent explanatory variable for urinary CER in the present study and eGFRcre is a useful marker to evaluate kidney function regardless of the presence of hypothyroidism.

The association between hypothyroidism and proteinuria in patients with chronic kidney disease: a cross-sectional study.

Hypothyroidism is known to be correlated with kidney function and nephrotic range proteinuria. However, it is uncertain whether non-nephrotic proteinuria is associated with hypothyroidism. This study aimed to evaluate the association of proteinuria and hypothyroidism in chronic kidney disease (CKD) patients. We conducted a cross-sectional study composed of 421 CKD patients in a single hospital with measurements of 24-h urine protein excretion (UP) and thyroid function tests. Spearman correlation analysis revealed that 24-h Cr clearance (24hrCcr) was positively (r = 0.273, p < 0.001) and UP was negatively (r = - 0.207, p < 0.001) correlated with free triiodothyronine. Frequency distribution analysis stratified by CKD stage and UP for hypothyroidism revealed that the prevalence of hypothyroidism was higher among participants with higher CKD stage and nephrotic range proteinuria. Multivariate logistic regression analysis revealed that 24hrCcr and UP were significantly correlated with hypothyroidism (24hrCcr/10 mL/min decrease: odds ratio [OR], 1.29; 95% confidence interval [CI], 1.18-1.41; UP/1 g increase: OR, 1.10; 95% CI, 1.03-1.17). In addition, nephrotic range proteinuria, but not moderate UP (UP: 1.5-3.49 g/day), was significantly correlated with hypothyroidism compared to UP < 0.5 g/day. In summary, decreased kidney function and nephrotic range proteinuria, not non-nephrotic proteinuria, are independently associated with the hypothyroidism.

Semaporin3A inhibitor ameliorates renal fibrosis through the regulation of JNK signaling.

Renal fibrosis is the common pathological pathway in progressive renal diseases. In the present study, we analyzed the roles of semaphorin 3 A (SEMA3A) on renal fibrosis and the effect of SEMA3A inhibitor (SEMA3A-I) using a unilateral ureteral obstruction (UUO) mouse model. Expression of SEMA3A in the proximal tubulus and neuropilin-1, a recepor of SEMA3A, in fibloblast and tubular cells were increased in UUO kidneys. The expression of myofibroblast marker tenascin-C and fibronection as well as renal fibrosis were increased in UUO kidneys, all of which were ameliorated by SEMA3A-I. In addition, the JNK signaling pathway, known as the target of SEMA3A signaling, was activated in proximal tubular cells and fibroblast cells after UUO surgery, and SEMA3A-I significantly attenuated the activation. In vitro, treatments with SEMA3A as well as transforming growth factor-ß1 (TGF-ß1) in human proximal tubular cells lost epithelial cell characteristics, and SEMA3A-I significantly ameliorated this transformation. The JNK inhibitor SP600125 partially reversed SEMA3A and TGF-ß1-induced cell transformation, indicating that JNK signaling is involved in SEMA3A-induced renal fibrosis. In addition, treatment with SEMA3A in fibroblast cells activated expression of tenascin-C, collagen type I, and fibronection, indicating that SEMA3A may accelerate renal fibrosis through the activation of fibroblast cells. Analysis of human data revealed the positive correlation between urinary SEMA3A and urinary N-acetyl-ß-d-glucosaminidase, indicating the association between SEMA3A and tubular injury. In conclusion, SEMA3A signaling is involved in renal fibrosis through the JNK signaling pathway and SEMA3A-I might be a therapeutic option for protecting from renal fibrosis.NEW & NOTEWORTHY Renal fibrosis is the common pathological pathway in the progression of renal diseases. This study, using a unilateral ureteral obstruction (UUO) mouse model, indicated increased semaphorin3A (SEMA3A) signaling in renal tubular cells as well as fibroblast cells under UUO surgery, and SEMA3A inhibitor ameliorated UUO-induced renal fibrosis through the regulation of JNK signaling. The study proposes the potential therapeutic option of SEMA3A inhibitor to treat renal fibrosis.

Deep Learning Could Diagnose Diabetic Nephropathy with Renal Pathological Immunofluorescent Images.

Artificial Intelligence (AI) imaging diagnosis is developing, making enormous steps forward in medical fields. Regarding diabetic nephropathy (DN), medical doctors diagnose them with clinical course, clinical laboratory data and renal pathology, mainly evaluate with light microscopy images rather than immunofluorescent images because there are no characteristic findings in immunofluorescent images for DN diagnosis. Here, we examined the possibility of whether AI could diagnose DN from immunofluorescent images. We collected renal immunofluorescent images from 885 renal biopsy patients in our hospital, and we created a dataset that contains six types of immunofluorescent images of IgG, IgA, IgM, C3, C1q and Fibrinogen for each patient. Using the dataset, 39 programs worked without errors (Area under the curve (AUC): 0.93). Five programs diagnosed DN completely with immunofluorescent images (AUC: 1.00). By analyzing with Local interpretable model-agnostic explanations (Lime), the AI focused on the peripheral lesion of DN glomeruli. On the other hand, the nephrologist diagnostic ratio (AUC: 0.75833) was slightly inferior to AI diagnosis. These findings suggest that DN could be diagnosed only by immunofluorescent images by deep learning. AI could diagnose DN and identify classified unknown parts with the immunofluorescent images that nephrologists usually do not use for DN diagnosis.