Blockage of autophagic flux is associated with lymphocytosis and higher percentage of tumoral cells in chronic lymphocytic leukemia of B cells.

PURPOSE: Autophagy has lately emerged as an important biological process with implications in several hematological pathologies. Recently, a growing body of evidence supports a putative role of autophagy in chronic lymphocytic leukemia; however, no definitive clue has been established so far. To elucidate this issue, we have developed a pilot study to measure autophagic flux in peripheral blood mononuclear cells from chronic lymphocytic leukemia patients, and explored its correlation with classical clinical/analytical parameters. METHODS/PATIENTS: Thirty-three chronic lymphocytic leukemia patients participated in the study. Autophagic flux in peripheral blood mononuclear cells was determined by western blot measuring the levels of the proteins p62 and lipidated LC3. Moreover, p62 mRNA levels were analyzed by RT-qPCR. RESULTS: Lymphocytosis and the percentage of tumoral lymphocytes in chronic lymphocytic leukemia patients statistically correlate with a blocked autophagic flux. CONCLUSION: Alterations in autophagic flux could play an important role in the physiopathology of chronic lymphocytic leukemia.

Mechanisms of the increased pressor response to vasopressors in the mesenteric bed of nitric oxide-deficient hypertensive rats.

In the present study we analyzed mesenteric vascular reactivity of chronic nitric oxide (NO)-deficient hypertensive rats (NW-nitro-L-Arginine Methyl Ester, L-NAME, 50 mg/kg/day, oral, 3 weeks). Perfusion pressure changes in response to cumulative additions of methoxamine and KCl were significantly increased in the mesenteric vessels of the L-NAME-treated as compared with vessels of the controls. Verapamil reduced the responses to methoxamine, but those of the hypertensive rats were still enhanced. In contrast, responses to KCl were almost completely abolished by verapamil. In mesenteric vessels perfused with zero calcium and high-potassium Krebs, pressor responses to the re-addition of calcium were also significantly enhanced in the hypertensive rats compared to the controls. Vasodilator responses to acetylcholine in KCl-preconstricted vessels, while still significant, were reduced in the L-NAME-treated rats. In this case, acute inhibition of NO blocked the vasodilator responses to acetylcholine and abolished the differences between the two groups. In methoxamine-preconstricted vessels and in the presence of acute inhibition of NO and prostaglandins, vasodilator responses to acetylcholine were significantly greater in the hypertensive vessels than in controls. In conclusion, the mesenteric vessels of L-NAME hypertensive rats show an enhanced response to vasopressors which is related to calcium entry. These data also reveal the existence of an enhanced role of a NO and prostaglandin-independent vasodilator factor, probably endothelium-derived hyperpolarizing factor that may play a compensatory role in the deficiency of NO.

Role of AT1 receptors in the renal papillary effects of acute and chronic nitric oxide inhibition.

Nitric oxide (NO) is a vasodilator substance controlling renal papillary blood flow (PBF) in the rat. In this study we have evaluated the role of AT1 angiotensin II receptors as modulators of the whole kidney and papillary vasoconstrictor effects induced by the acute or chronic inhibition of NO synthesis. Experiments have been performed in anesthetized, euvolemic Munich-Wistar rats prepared for the study of renal blood flow (RBF) and PBF. In normal rats, acute administration of the NO synthesis inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) increased mean arterial pressure (MAP) and decreased RBF and PBF. Either acute or chronic treatment with the AT1 receptor blocker losartan did not modify the decreases in RBF or PBF secondary to L-NAME. In animals made hypertensive by chronic inhibition of NO, basal MAP was higher, whereas RBF and PBF were lower than in the controls. In these animals, acute or chronic administration of losartan decreased MAP and increased both RBF and PBF significantly. These results indicate that, under normal conditions, the decreases in RBF or PBF induced by the acute inhibition of NO synthesis are not modulated by AT1-receptor stimulation. However, the arterial hypertension, renal vasoconstriction, and reduced PBF present in chronic NO-deficient hypertensive rats is partially due to the effects of angiotensin II, via stimulation of AT1-receptors.