Biochemical evidence for adhesion-promoting role of major intrinsic protein isolated from both normal and cataractous human lenses

In this study, we tested the adhesion-promoting role of major intrinsic protein from both normal human (cadaver) and senile cataractous lenses. Junctional membrane solubilized proteins and pure major intrinsic protein obtained from both type of lenses were reconstituted in neutral phosphatidylcholine liposomes. The interaction of these liposomes with phosphatidylserine vesicles was studied by resonance energy transfer. Our results show that normal human lens junction solubilized proteins and pure major intrinsic protein isolated from them promote adhesion. No quenching effect was observed when major intrinsic protein was omitted in the vesicle reconstitution, no other intrinsic protein of normal human junctional membrane provoked the adhesive effect. In contrast, major intrinsic protein isolated from human senile cataractous lens fails to induce adhesion. The proteolytic cleavages that in vitro originate major intrinsic protein 22 000 Da did not blunt its adhesive capability, suggesti

Regulation of the sodium-phosphate cotransporter Pit-1 and its role in vascular calcification

Vascular calcification is caused by the deposition of basic calcium phosphate crystals in blood vessels, myocardium, and/or cardiac valves. Calcification decreases artery wall compliance, and arterial calcification is associated to mortality in hyperphosphatemic renal failure and diabetes mellitus. The calcification of the tunica media characterizes the arteriosclerosis observed with age, diabetes and end stage-renal disease, and it can develop independently from intima calcification. As part of the vascular calcification mechanism, vascular smooth muscle cells (VSMC) experience a transition from a contractile to an osteochondrogenic phenotype and a sequence of molecular events that are typical of endochondral ossification. The current evidence indicates a key role of increased phosphate uptake by VSMC for calcification, which supplies the substrate for hydroxyapatite formation and could trigger or potentiate VSMC transdiferentiation. The present review analyzes the sodium-phosphate c

Assesment of arterial damage by noninvasive peripheral arterial tonometry in non-diabetic hemodialysis patients Daño arterial asociado a la enfermedad renal crónica: Evaluación mediante técnicas de laboratorio no invasivo en pacientes hemodializados

Background: Hemodialysis patients (HD) display high rates of cardiac disease and mortality. The cardiovascular morbidity and mortality of HD patients is attributable in a signifi cant proportion to endothelial dysfunction, arterial stiffness, and vascular calcifi cations. Aim: To measure vascular reactivity in HD subjects and compare them with healthy volunteers. Material and Methods: Forty eight non diabetic patients aged 58 ± 4.6 years (29 males) on hemodialysis for a mean lapse of 4.8 years were studied. Arterial stiffness was measured in the radial artery. Pulse wave velocity was measured by noninvasive peripheral arterial tonometry in carotid and femoral arteries. Endothelial function was assessed, measuring reactive hyperemia response after a 5 min period of ischemia. As a control, all values were also measured in age and gender-matched healthy volunteers. Results: Arterial stiffness was signifi cantly higher in HD patients than controls (23.9 ± 3.3 and 18.4 ± 3.4% respectively

Effect of Casein-Derived Peptides on D-Xylose Absorption Assessed by H2 Breath Test in Normal Volunteers

Studies have shown a promoting effect of food on small intestinal absorption. Casein hydrolysate seems be more effective in increasing of D-xylose absorption in dogs than the whole protein and lactulose. The purpose this study was to analyze the effect of groups of peptides derived from casein hydrolysate on the absorption of D-Xylose and intestinal transit time in normal subjects. Seven normal volunteers participated in the study. Three peptide fractions were isolated from casein enzymatic hydrolysate by means of a preparative HPLC silica column. On separate days subjets drank test solutions containing lactulose, D-xylose, and D-xylose with one of three peptide groups. The hydrogen breath test was used to indirectly estimate D-xylose absorption and orocecal transit time. Two peptide fractions when added to D-xylose were followed by an increased absorption characterized by decreased H2 production. A nonstatistically significant increase of orocecal transit time was observed with these peptides

Comparison of extra renal potassium disposal in hypertensive, diabetic and normal subjects Estudio comparativo del manejo extrarrenal de potasio en sujetos controles, pacientes hipertensos y diabéticos

Background: Sodium and potassium ions are involved in the regulation of blood pressure and the genesis of hypertension. Aim: To assess internal potassium balance, as a measure of sodium pump activity, in subjects with essential hypertension and diabetic patients. Patients and methods: Eleven hypertensive subjects, 5 non-insulin-dependent diabetics and 16 age matched controls were studied. An acute oral load of 0.8 mEq/Kg body weight of KCl was administered and blood samples were drawn every 30 min thereafter, until 120 min, to measure plasma K+ levels. Urinary K+ excretion during this period was also measured. In eight hypertensive patients, the test was repeated after two week of supplementation with 60 mEq/day of KCl. The maximal increase in plasma potassium levels and the time required to achieve the maximum concentration was recorded. Results: All patients had normal serum creatinine levels. Mean fasting blood glucose of diabetic patients was 133 ± 15.1 mg/dl. No difference betwee

Effect of Chronic Renal Failure on NaK-ATPase A1 and a2 mRNA Transcription in Rat Skeletal Muscle

Artículo de publicación ISIPrevious studies have suggested that an alteration in the expression of the NaK-ATPase of muscle may be an important determinant of enhanced insulin sensitivity in chronic renal failure. Therefore, in the present studies we have examined the effect of uremia on the NaK-ATPase a isoforms in skeletal muscle, at the level of mRNA expression and enzymatic activity. The activity of the sodium pump, as measured ouabain-sensitive 'Rb/K uptake in soleus muscle, revealed a reduction in the activity in uremia, related to the increment in plasma creatinine values. The decrement in 86Rb uptake by the rat soleus muscle of experimental animals was associated with changes on NaK-ATPase gene product. Northern analysis of mRNA revealed isoform-specific regulation of Na,K-ATPase by uremia in skeletal muscle: a decrease of - 50% in al subunit Na,K-ATPase mRNA, as compared to controls. The decrement in al mRNA correlates with the decreased activity of the Na,K-ATPase in uremia, under basal conditions and with the almost complete inhibition of the Na,K-ATPase, of uremic tissue by a concentration of 10-' M ouabain. Although the activity of the a2 isoform pump was not modified by uremia, the 3.4-kb message for this enzyme was increased 2.2-fold; this discrepancy is discussed. Altogether these findings demonstrate that the defective extrarenal potassium handling in uremia is at least dependent in the expression of a1 subunit of the Na,K-ATPase

L-NIL prevents the ischemia and reperfusion injury involving TLR-4, GST, clusterin, and NFAT-5 in mice

Copyright © 2019 the American Physiological Society.—On renal ischemia-reperfusion (I/R) injury, recruitment of neutrophils during the inflammatory process promotes local generation of oxygen and nitrogen reactive species, which, in turn, are likely to exacerbate tissue damage. The mechanism by which inducible nitric oxide synthase (iNOS) is involved in I/R has not been elucidated. In this work, the selective iNOS inhibitor L-N6-(1-iminoethyl)lysine (L-NIL) and the NOS substrate L-arginine were employed to understand the role of NOS activity on the expression of particular target genes and the oxidative stress elicited after a 30-min of bilateral renal ischemia, followed by 48-h reperfusion in Balb/c mice. The main findings of the present study were that pharmacological inhibition of iNOS with L-NIL during an I/R challenge of mice kidney decreased renal injury, prevented tissue loss of integrity, and improved renal function. Several novel findings regarding the molecular mechanism by which iNOS inhibition led to these protective effects are as follows: 1) a prevention of the I/R-related increase in expression of Toll-like receptor 4 (TLR-4), and its downstream target, IL-1α; 2) reduced oxidative stress following the I/R challenge; noteworthy, this study shows the first evidence of glutathione S-transferase (GST) inactivation following kidney I/R, a phenomenon fully prevented by iNOS inhibition; 3) increased expression of clusterin, a survival autophagy component; and 4) increased expression of nuclear factor of activated T cells 5 (NFAT-5) and its target gene aquaporin-1. In conclusion, prevention of renal damage following I/R by the pharmacological inhibition of iNOS with L-NIL was associated with the inactivation of proinflammatory pathway triggered by TLR-4, oxidative stress, renoprotection (autophagy inac-tivation), and NFAT-5 signaling pathway