ABSTRACT
BACKGROUND: The mechanism leading to the development of IgA nephropathy (IgAN) remains to be completely understood. Endothelin-1 (ET-1) as well as angiotensin II (AngII) promote glomerular injury, tubulointerstitial inflammation, and fibrosis leading to chronic kidney disease. Sparsentan, a dual endothelin angiotensin receptor antagonist (DEARA), recently received accelerated approval in United States for the reduction of proteinuria in adults with IgAN at high risk of disease progression. To elucidate the mechanisms by which sparsentan is efficacious in IgAN, we examined the effect of treatment in gddY mice, a spontaneous IgAN mouse model, versus the monoselective angiotensin II type 1 receptor (AT1R) antagonist, losartan, on the development of renal injury at doses resulting in similar blood pressure lowering. METHODS: Four-week-old gddY mice were given control chow, chow containing sparsentan, or drinking water containing losartan until 12 or 20 weeks old. RESULTS: Remarkably, the albumin:creatine ratio (ACR) was attenuated more rapidly and to a greater extent in mice treated with sparsentan than those treated with losartan. The decrease in ACR from baseline after 4 weeks of treatment correlated with beneficial effects of sparsentan on glomerulosclerosis and protection of podocytes and glycocalyx after 16 weeks of treatment across treatment groups; thus, sparsentan treatment delayed development of renal injury to a greater extent than losartan. Expression of mRNA for ET-1, ETAR, and AT1R and proinflammatory genes was upregulated in 12-week-old gddY mice and was prevented by sparsentan and losartan to a comparable extent. CONCLUSIONS: The results of this study, and in light of the results of the phase 3 PROTECT trial, provide a novel perspective and understanding of the mechanisms by which sparsentan has a beneficial renoprotective effect against IgAN compared to AT1R antagonism alone.
ABSTRACT
Hypertension and constipation are major hemodialysis complications. Salt restriction is one of the most important nonpharmacological interventions in managing hypertension. In patients undergoing hemodialysis, nonpharmacological strategies to manage constipation are extremely difficult to develop owing to the presence of excess dietary potassium and fluids. Frugra®, which is a cereal food that has a low salt content of 0.5 g per serving, may help reduce salt intake. Additionally, Frugra is rich in dietary fiber, thereby beneficial for such patients. In this study, we evaluated the safety and efficacy of Frugra in patients undergoing hemodialysis, focusing mainly on blood pressure and bowel health by changing the usual breakfast meal to Frugra for 8 weeks. We enrolled 11 patients undergoing hemodialysis. Despite the absence of changes in the patients' dry weight levels, their systolic blood pressure levels decreased from 155.5 ± 20.9 mmHg to 137.9 ± 10.3 mmHg after 2 months (P < 0.05). All participants reported improvements in bowel movement, and the levels of indoxyl sulfate, a representative gut-derived uremic toxin, were decreased from 49.3 µg/ml to 33.4 µg/ml. Furthermore, adverse events including electrolyte abnormalities were not observed. Therefore, Frugra may be useful to manage the health of patients undergoing hemodialysis.
Subject(s)
Constipation/etiology , Constipation/therapy , Diet, Sodium-Restricted , Dietary Fiber/administration & dosage , Edible Grain , Foods, Specialized , Hypertension/etiology , Hypertension/therapy , Renal Dialysis/adverse effects , Blood Pressure , Defecation , Edible Grain/chemistry , Female , Food Analysis , Foods, Specialized/analysis , Humans , Hypertension/physiopathology , Indican/blood , Male , Middle Aged , Nutrients/analysis , Pilot Projects , Safety , Treatment OutcomeABSTRACT
A 70-year-old woman underwent a renal biopsy due to nephrotic syndrome. She had suffered from nontuberculous mycobacterial infection (NTM) for 14 years. The patient was diagnosed as having membranoproliferative glomerulonephritis (MPGN) type 3 and immunoglobulin (Ig)-associated MPGN based upon LM/erythromycin and IF findings, respectively. In high-magnification imaging, electron-dense deposits showed immunotactoid glomerulopathy (ITG). There was no evidence of hematological cancer, and the patient improved after receiving treatments for NTM. To the best of our knowledge, this patient is the first to show an association between ITG and NTM. Although ITG is generally considered as related to lymphoproliferative disease, it is suggested that ITG is driven by bacterial infection and is a potential outcome of Ig-associated MPGN.
