Aspartame, as an artificial sweetener, does not affect renal function and antioxidative states in mice.

BACKGROUND AND OBJECTIVE: Aspartame (L-aspartyl L-phenylalanine methyl ester) is an artificial sweetener widely used as a sugar substitute. There are concerns regarding the effects of high aspartame doses on the kidney owing to oxidative stress; however, whether the maximum allowed dose of aspartame in humans affects the kidneys remains unknown. Therefore, in this study, we investigated whether the maximum allowed dose of aspartame in humans affects the kidneys. METHODS: In this study, animals were fed a folate-deficient diet to mimic human aspartame metabolism. Eight-week-old ICR mice were divided into control (CTL), 40 mg/kg/day of aspartame-administered (ASP), folate-deficient diet (FD), and 40 mg/kg/day of aspartame-administered with a folate-deficient diet (FD + ASP) groups. Aspartame was administered orally for eight weeks. Thereafter, we evaluated aspartame's effect on kidneys via histological analysis. RESULTS: There were no differences in serum creatinine and blood urea nitrogen levels between the CTL and ASP groups or between the FD and FD + ASP groups. There was no histological change in the kidneys in any group. The expression of superoxide dismutase and 4-hydroxy-2-nonenal in the kidney did not differ between the CTL and ASP groups or the FD and FD + ASP groups. CONCLUSION: Our findings indicate that the allowed doses of aspartame in humans may not affect kidney function or oxidative states.

Hydroxychloroquine suppresses anti-GBM nephritis via inhibition of JNK/p38 MAPK signaling.

BACKGROUND: Anti-glomerular basement membrane (anti-GBM) nephritis, characterized by glomerular crescent formation, requires early treatment because of poor prognosis. Hydroxychloroquine (HCQ) is an antimalarial drug with known immunomodulatory, anti-inflammatory, and autophagy inhibitory effects; it is recognized in the treatment of autoimmune diseases such as systemic lupus erythematosus. However, its effect on anti-GBM nephritis remains unknown. In this study, we investigated the effect of HCQ on anti-GBM nephritis in rats. METHODS: Seven-weeks-old male WKY rats were administered anti-GBM serum to induce anti-GBM nephritis. Either HCQ or vehicle control was administered from day 0 to day 7 after the induction of nephritis. Renal function was assessed by measuring serum creatinine, proteinuria, and hematuria. Renal histological changes were assessed by PAS staining and Masson trichrome staining, and infiltration of macrophages was assessed by ED-1 staining. Mitogen-activated protein kinase (MAPK) was evaluated by western blotting, while chemokine and inflammatory cytokines were evaluated by enzyme-linked immunosorbent assay using urine sample. RESULTS: HCQ treatment suppressed the decline in renal function. Histologically, extracapillary and intracapillary proliferations were observed from day 1, while fibrinoid necrosis and ED-1 positive cells were observed from day 3. Rats with anti-GBM nephritis showed high levels of monocyte chemotactic protein-1 and tumor necrosis factor-α. These changes were significantly suppressed following HCQ treatment. In addition, HCQ suppressed JNK/p38 MAPK phosphorylation. CONCLUSION: HCQ attenuates anti-GBM nephritis by exerting its anti-inflammatory effects via the inhibition of JNK/p38 MAPK activation, indicating its therapeutic potential against anti-GBM nephritis.

Mitochonic acid-5 ameliorates chlorhexidine gluconate-induced peritoneal fibrosis in mice.

Peritoneal fibrosis is a serious complication of long-term peritoneal dialysis, attributable to inflammation and mitochondrial dysfunction. Mitochonic acid-5 (MA-5), an indole-3-acetic acid derivative, improves mitochondrial dysfunction and has therapeutic potential against various diseases including kidney diseases. However, whether MA-5 is effective against peritoneal fibrosis remains unclear. Therefore, we investigated the effect of MA-5 using a peritoneal fibrosis mouse model. Peritoneal fibrosis was induced in C57BL/6 mice via intraperitoneal injection of chlorhexidine gluconate (CG) every other day for 3 weeks. MA-5 was administered daily by oral gavage. The mice were divided into control, MA-5, CG, and CG + MA-5 groups. Following treatment, immunohistochemical analyses were performed. Fibrotic thickening of the parietal peritoneum induced by CG was substantially attenuated by MA-5. The number of α-smooth muscle actin-positive myofibroblasts, transforming growth factor ß-positive cells, F4/80-positive macrophages, monocyte chemotactic protein 1-positive cells, and 4-hydroxy-2-nonenal-positive cells was considerably decreased. In addition, reduced ATP5a1-positive and uncoupling protein 2-positive cells in the CG group were notably increased by MA-5. MA-5 may ameliorate peritoneal fibrosis by suppressing macrophage infiltration and oxidative stress, thus restoring mitochondrial function. Overall, MA-5 has therapeutic potential against peritoneal fibrosis.

Association between Serum Phosphate Levels and the Development of Aortic Stenosis in Patients Undergoing Hemodialysis.

We aimed to investigate the factors associated with the development of aortic stenosis (AS) in patients undergoing hemodialysis (HD), and to elucidate the prognosis of HD patients with AS. Patients on HD that had also undergone echocardiography at Nagasaki Renal Center between July 2011 and June 2012 were included. Patients with AS at the time of inclusion were excluded. The diagnosis of AS was based on an annual routine or additional echocardiography. The patients were followed up until June 2021. The association between patient background and AS was also evaluated. Of the 302 patients (mean age, 67.4 ± 13.3 years; male, 58%; median dialysis history, 4.7 years), 60 developed AS and 10 underwent aortic valve replacement. A Cox proportional hazards model revealed that age (hazard ratio (HR), 1.07; 95% confidential interval (CI), 1.04-1.10; p < 0.001) and serum phosphate levels (HR, 1.40; 95%CI, 1.16-1.67, p < 0.001) were independent risk factors for developing AS. Incidentally, there was no significant mortality difference between patients with AS and those without (p = 0.53). Serum phosphate levels are a risk factor for developing AS and should be controlled. Annual echocardiography may contribute to the early detection of AS and improves the prognosis of patients undergoing HD.

Association of Urinary Dickkopf-3 with Residual Renal Function Decline in Patients Undergoing Peritoneal Dialysis.

Background and Objectives: Urinary levels of dickkopf-3 (DKK-3) are associated with poor renal survival in patients with non-dialytic chronic kidney disease. However, it remains unknown whether urinary DKK-3 levels can predict residual renal function (RRF) decline in patients undergoing peritoneal dialysis (PD). Therefore, we investigated the correlation between urinary levels of DKK-3 and the subsequent rate of RRF decline in PD patients. Materials and Methods: This study included 36 PD patients who underwent multiple peritoneal equivalent tests during 2011-2021. The relationship between baseline clinical characteristics and the subsequent annual rate of Kt/V decline was investigated. Results: The annual rate of renal Kt/V decline was 0.29 (range: 0.05-0.48), which correlated with renal Kt/V (r = 0.55, p = 0.0005) and 24 h urinary DKK-3 excretion (r = 0.61, p < 0.0001). Similarly, 24 h urinary DKK-3 excretion (ß = 0.44, p = 0.0015) and renal Kt/V (ß = 0.38, p = 0.0059) were independently associated with the annual rate of renal Kt/V decline in multivariate analyses. Conclusions: Urinary DKK-3 assessment may help identify PD patients at a high risk of RRF decline.

Anti-glomerular Basement Membrane Disease with Antiphospholipid Syndrome.

A 48-year-old woman presented with a fever, microscopic hematuria, proteinuria, and rapid deterioration of the renal function. Pulmonary alveolar hemorrhaging and a high level of anti-glomerular basement membrane (GBM) antibodies (700 IU/mL) were observed. Based on her medical history and positive findings of serum lupus anticoagulant, anti-phospholipid antibody syndrome (APS) was suspected. A renal biopsy revealed cellular crescentic glomerulonephritis with thrombosis, suggesting anti-GBM disease with catastrophic APS. The patient was treated with pulse steroid therapy, plasma exchange, hemodialysis, and intravenous cyclophosphamide pulse therapy. To our knowledge, this is the first report of a patient with anti-GBM disease and APS.

Hexapeptide derived from prothymosin alpha attenuates cisplatin-induced acute kidney injury.

BACKGROUND: Prothymosin alpha (ProTα) is a nuclear protein expressed in virtually all mammalian tissues. Previous studies have shown that ProTα exhibits protective effects against ischemia-induced cell death in various cell types. Recently, the 6-residue peptide P6Q (NEVDQE), the modified form of the active 6-residue core (51-56) in ProTα, has also been shown to have protective effects against retinal ischemia. However, it remains to be elucidated whether P6Q is effective against acute kidney injury (AKI). Therefore, we investigated the renoprotective effect of P6Q on cisplatin-induced AKI. METHODS: Cultured HK-2 cells were treated with cisplatin for 24 h and pretreatment with ProTα or P6Q was carried out 30 min before cisplatin treatment. Cell viability was evaluated using the MTT assay. In an in vivo study, 8-week-old male Wistar rats were divided into control, cisplatin treated, and cisplatin treated with P6Q injection groups. In the last of these, P6Q was injected intravenously before cisplatin treatment. Then, we evaluated the renoprotective effect of P6Q. RESULTS: In the study on cultured cells, pretreatment with ProTα or P6Q prevented cisplatin-induced cell death. In the in vivo study, pretreatment with P6Q significantly attenuated cisplatin-induced increase in serum creatinine and blood urea nitrogen levels, renal tubular cell injury, and apoptosis. Moreover, P6Q attenuated the mitochondrial apoptotic pathway and accelerated Akt phosphorylation after cisplatin-induced renal damage. CONCLUSION: Taken together, our findings indicate that P6Q can attenuate cisplatin-induced AKI and suppress the mitochondrial apoptotic pathway via Akt phosphorylation. These data suggest that P6Q has potential as a preventative drug for cisplatin-induced AKI.

A Comparative Study of the Hemoglobin-Maintaining Effects Between Epoetin-ß Pegol and Darbepoetin-α in Patients with Chronic Kidney Disease During 3 Months Before Dialysis Initiation.

BACKGROUND AND OBJECTIVE: We compared the hemoglobin-maintaining effects between continuous erythropoietin receptor activator (CERA) and darbepoetin-α (DA) in patients with chronic kidney disease (CKD) during the 3 months before dialysis initiation. METHODS: This study was conducted with 37 CERA-administered patients and 26 DA-administered patients who had initiated dialysis at a participating facility between January 2012 and December 2014. We investigated clinical laboratory data 3 months before and at dialysis initiation, and compared these data between the CERA and DA groups. RESULTS: No significant differences in hemoglobin level or reticulocyte count were found between the two groups 3 months before dialysis initiation. However, at dialysis initiation, the hemoglobin level (CERA 9.82 ± 1.52 vs. DA 8.79 ± 1.07 g/dL; P = 0.003) and the reticulocyte count (CERA 5.21 ± 2.95 vs. DA 3.15 ± 1.62 × 104/µL; P = 0.004) were significantly higher in the CERA group than in the DA group. Moreover, the extent of changes in the erythropoietin resistance index during the 3 months before dialysis initiation was significantly increased in the DA group compared with the CERA group. CONCLUSIONS: Our results suggest that CERA may be more effective than DA in maintaining hemoglobin levels in patients with CKD during 3 months before dialysis initiation.