Upregulation of Piezo2 in the mesangial, renin, and perivascular mesenchymal cells of the kidney of Dahl salt-sensitive hypertensive rats and its reversal by esaxerenone.

The recent discovery of mechanosensitive ion channels has promoted mechanobiological research in the field of hypertension and nephrology. We previously reported Piezo2 expression in mouse mesangial and juxtaglomerular renin-producing cells, and its modulation by dehydration. This study aimed to investigate how Piezo2 expression is altered in hypertensive nephropathy. The effects of the nonsteroidal mineralocorticoid receptor blocker, esaxerenone, were also analyzed. Four-week-old Dahl salt-sensitive rats were randomly assigned to three groups: rats fed a 0.3% NaCl diet (DSN), rats fed a high 8% NaCl diet (DSH), and rats fed a high salt diet supplemented with esaxerenone (DSH + E). After six weeks, DSH rats developed hypertension, albuminuria, glomerular and vascular injuries, and perivascular fibrosis. Esaxerenone effectively decreased blood pressure and ameliorated renal damage. In DSN rats, Piezo2 was expressed in Pdgfrb-positive mesangial and Ren1-positive cells. Piezo2 expression in these cells was enhanced in DSH rats. Moreover, Piezo2-positive cells accumulated in the adventitial layer of intrarenal small arteries and arterioles in DSH rats. These cells were positive for Pdgfrb, Col1a1, and Col3a1, but negative for Acta2 (αSMA), indicating that they were perivascular mesenchymal cells different from myofibroblasts. Piezo2 upregulation was reversed by esaxerenone treatment. Furthermore, Piezo2 inhibition by siRNA in the cultured mesangial cells resulted in upregulation of Tgfb1 expression. Cyclic stretch also upregulated Tgfb1 in both transfections of control siRNA and Piezo2 siRNA. Our findings suggest that Piezo2 may have a contributory role in modulating the pathogenesis of hypertensive nephrosclerosis and have also highlighted the therapeutic effects of esaxerenone on salt-induced hypertensive nephropathy. Mechanochannel Piezo2 is known to be expressed in the mouse mesangial cells and juxtaglomerular renin-producing cells, and this was confirmed in normotensive Dahl-S rats. In salt-induced hypertensive Dahl-S rats, Piezo2 upregulation was observed in the mesangial cells, renin cells, and notably, perivascular mesenchymal cells, suggesting its involvement in kidney fibrosis.

A Case Involving Massive Insulin Overdose: Direct and Indirect Conditions Requiring Extended Management of Serum Potassium.

BACKGROUND Insulin lowers not only blood glucose levels but also serum potassium levels by driving potassium into the cells. Hypokalemia can occur during aggressive treatment of hypoglycemia in patients with insulin overdose and is a well-documented clinical phenomenon; however, there are no studies describing delayed hyperkalemia occurring after initial treatment in patients with insulin overdose. CASE REPORT A 23-year-old male with a history of type 2 diabetes mellitus and self-medicating with insulin, attempted suicide by subcutaneously injecting 2100 units of insulin. He was admitted to our emergency department due to recurrent hypoglycemia. Continuous administration of 50% glucose and potassium via a central venous catheter was performed to maintain his glucose levels above 80 mg/dL and serum potassium level between 3.5 and 4.0 mEq/L. Because his serum potassium level exceeded 4.5 mEq/L at day 3 after admission, the dosage was adjusted accordingly. After his serum potassium level declined to 3.0 mEq/L, his potassium level abruptly increased to 6.0 mEq/L at day 5 after admission. The patient was placed on a potassium-restricted diet and administered furosemide. Potassium infusion was also discontinued. After serum potassium levels returned to the normal range without interventional therapies, the patient was discharged to home on day 14. CONCLUSIONS In cases of high-dose insulin overdose, management of hyperkalemia following recovery from hypoglycemia is a critical aspect of patient management. Conservative administration of potassium to correct initial hypokalemia may be considered in patients with high-dose insulin overdose.

Effect of high-dose vitamin C therapy on severe burn patients: a nationwide cohort study.

BACKGROUND: Vitamin C is a well-documented antioxidant that reduces oxidative stress and fluid infusion in high doses; however, the association between high-dose vitamin C and reduced mortality remains unclear. This study evaluates the effect of high-dose vitamin C in severe burn patients under two varying thresholds. METHODS: We enrolled adult patients with severe burns (burn index ≥ 15) who were registered in the Japanese Diagnosis Procedure Combination national inpatient database from 2010 to 2016. Propensity score matching was performed between patients who received high-dose vitamin C within 1 day of admission (vitamin C group) and those who did not (control group). High-dose vitamin C was defined as a dosage in excess of 10 g or 24 g within 2 days of admission. The primary outcome was in-hospital mortality. RESULTS: Eligible patients (n = 2713) were categorized into the vitamin C group (n = 157) or control group (n = 2556). After 1:4 propensity score matching, we compared 157 and 628 patients who were administered high-dose vitamin C (> 10-g threshold) and controls, respectively. Under this particular threshold, high-dose vitamin C therapy was associated with reduced in-hospital mortality (risk ratio, 0.79; 95% confidence interval, 0.66-0.95; p = 0.006). In contrast, in-hospital mortality did not differ between the control and high-dose vitamin C group under the > 24-g threshold (risk ratio, 0.83; 95% confidence interval, 0.68-1.02; p = 0.068). CONCLUSIONS: High-dose vitamin C therapy was associated with reduced mortality in patients with severe burns when used under a minimum threshold of 10 g within the first 2 days of admission. While "high-dose" vitamin C therapy lacks a universal definition, the present study reveals that different "high-dose" regimens may yield improved outcomes.

Effect of nagilactone E on cell morphology and glucan biosynthesis in budding yeast Saccharomyces cerevisiae.

Nagilactones are norditerpene dilactones isolated from the root bark of Podocarpus nagi. Although nagilactone E has been reported to show antifungal activities, its activity is weaker than that of antifungals on the market. Nagilactone E enhances the antifungal activity of phenylpropanoids such as anethole and isosafrole against nonpathogenic Saccharomyces cerevisiae and pathogenic Candida albicans. However, the detailed mechanisms underlying the antifungal activity of nagilactone E itself have not yet been elucidated. Therefore, we investigated the antifungal mechanisms of nagilactone E using S. cerevisiae. Although nagilactone E induced lethality in vegetatively growing cells, it did not affect cell viability in non-growing cells. Nagilactone E-induced morphological changes in the cells, such as inhomogeneous thickness of the glucan layer and leakage of cytoplasm. Furthermore, a dose-dependent decrease in the amount of newly synthesized (1, 3)-ß-glucan was detected in the membrane fractions of the yeast incubated with nagilactone E. These results suggest that nagilactone E exhibits an antifungal activity against S. cerevisiae by depending on cell wall fragility via the inhibition of (1, 3)-ß-glucan biosynthesis. Additionally, we confirmed nagilactone E-induced morphological changes of a human pathogenic fungus Aspergillus fumigatus. Therefore, nagilactone E is a potential antifungal drug candidate with fewer adverse effects.

Lecithinized superoxide dismutase suppresses free radical substrates during the early phase of burn care in rats.

Severe hypovolemia is caused by an increase in blood vessel permeability in the early phase after an extensive burn; massive fluid volume replacement has been used for the treatment of this condition. The release of oxygen free radicals and chemical mediators, especially from skin tissue, induces the increase in blood vessel permeability. Free radical burst is associated with ischemia-related skin tissue injury. Although various antioxidant therapies have been used to inhibit the consequences of hypovolemia, an effective method has not been established. To elucidate the protective effects of lecithinized superoxide dismutase (PC-SOD) as an antioxidant agent. Each rat sustained a 30% total body surface area burn (n = 20) on the back by the Walker and Mason method were allocated into three groups: (1) no treatment group (n = 6), (2) a low dose of PC-SOD (0.67 mg/kg) group (n = 7), and (3) a high dose of PC-SOD (1.33 mg/kg) group (n = 7). The concentrations of malondialdehyde and SOD in the serum, skin tissue, and lung tissue were measured in each group 1 hour after burning. Both low and high doses of PC-SOD prevented malondialdehyde concentration associated with free radical burst after burning compared with the no treatment group (P < .05); serum (27.7 +/- 6.8, 10.8 +/- 2.7, and 12.1 +/- 2.8 nmol/L), skin tissue (2251.3 +/- 560.5, 802.7 +/- 228.8, and 790.1 +/- 188.3 nmol/wet.g), and lung (157.3 +/- 19.5, 109.1 +/- 23.9, and 81.9 +/- 20.3 nmol/wet.g). These data suggest that PC-SOD may be a protective agent against free radical-induced vasodilatation caused by severe, extensive burns.

Biological evaluation of fluorinated p-boronophenylalanine derivatives as a boron carrier.

Boron neutron capture therapy (BNCT) and magnetic resonance imaging (MRI) are quite attractive techniques for treatment and diagnosis of cancer, respectively. In order to develop practical materials utilizing both for BNCT and MRI, fluorinated p-boronophenylalanines and their alcohol derivatives had already been designed and synthesized. In the present paper the cytotoxicity, the incorporated amount into cancer cells, and the tumor cell killing effects of these compounds were elucidated to evaluate their usefulness as a boron carrier.