Seven antiphospholipid antibodies in HIV-positive patients: correlation with clinical course and laboratory findings

OBJECTIVE: To compare the clinical course of HIV-1-infected patients, their CD4+, CD8+ T lymphocytes, and viral loads (VL) with the levels of seven antiphospholipid antibodies (aPLs) before, during, and after the highly active antiretroviral therapy (HAART). PATIENTS AND METHODS: aPLs were examined in patients (20 men, 10 women, aged 12-64 years, median 33 years) from the AIDS center of Western Bohemia before the initiation of HAART, and two (23 patients), and five (20 patients) years later. Flow-cytometry was used for CD4+ and CD8+ T lymphocytes analysis, commercial kits were used for VL-measurements, and commercial enzyme-linked immunosorbent assay (ELISA) was used to determine serum levels of anti-beta2-glycoprotein I (GPI) of immunoglobulin G (IgG) and IgA isotypes, and anticardiolipin levels (ACA) of IgG and IgM isotypes. APLs screening also included L-alpha-phosphatidic (ph) acid, L-alpha-phosphatidylethanolamine, L-alpha-phosphatidyl-DL-glycerol, L-alpha-phosphatidylinositol, and L-alpha-phosphatidylserine of IgG and IgM autoantibodies. Statistical analysis was performed using cut-off levels for immunoglobulin-isotypes of aPLs using 3 S.D. or 95th percentile calculated using Statgraphics-software. RESULTS: In 14 of 21 patients treated by HAART an increased number of CD4+ T lymphocytes was detected, and in 14 of 21 patients VL decreased below detection threshold during the 5 years of observation. We did not observe correlations of aPLs with age, the initial low CD4+ and high number of CD8+ T lymphocytes, and the viremic levels over the entire observation period. We did not find the elevation of aPLs in 2 of 5 patients in stage C (AIDS). Ten of 11 HIV-positive homosexuals had positive aPLs, and the same result was seen in 7 of 10 patients infected through heterosexual intercourse. aPLs levels were significantly increased in 18 of 30 patients at the beginning of HAART. ACA IgG was elevated in 14 of 30 cases, IgG antibodies against L-alpha-ph-acid in 5 of 30, ph-ethanolamine in 10 of 30, ph-inositol in 9 of 30, and L-serine in 14 of 30, combined positivity of six aPLs together was detected in 10 HIV positive patients. Significantly decreased levels of aPLs because of HAART were found in eight patients. APLs were still present in only four patients after 5 years of the treatment. Abnormalities in blood clotting were not present in any of our patients. CONCLUSION: Results of screening for seven aPLs in HIV-positive patients suggest that HAART also positively influences the autoimmune response represented by aPLs levels, but individual differences in aPLs levels were observed.     

D-propranolol attenuates lysosomal iron accumulation and oxidative injury in endothelial cells

The influence of selected beta-receptor blockers on iron overload and oxidative stress in endothelial cells (ECs) was assessed. Confluent bovine ECs were loaded with iron dextran (15 muM) for 24 h and then exposed to dihydroxyfumarate (DHF), a source of reactive oxygen species, for up to 2 h. Intracellular oxidant formation, monitored by fluorescence of 2',7'-dichlorofluorescin (DCF; 30 microM), increased and peaked at 30 min; total glutathione decreased by 52 +/- 5% (p < 0.01) at 60 min. When the ECs were pretreated 30 min before iron loading with 1.25 to 10 microM d-propranolol, glutathione losses were attenuated 15 to 80%, with EC(50) = 3.1 microM. d-Propranolol partially inhibited the DCF intensity increase, but atenolol up to 10 microM was ineffective. At 2 h, caspase 3 activity was elevated 3.2 +/- 0.3-fold (p < 0.01) in the iron-loaded and DHF-treated ECs, and cell survival, determined 24 h later, decreased 47 +/- 6% (p < 0.01). Ten micromoles of d-propranolol suppressed the caspase 3 activation by 63% (p < 0.05) and preserved cell survival back to 88% of control (p < 0.01). In separate experiments, 24-h iron loading resulted in a 3.6 +/- 0.8-fold increase in total EC iron determined by atomic absorption spectroscopy; d-propranolol at 5 microM reduced this increase to 1.5 +/- 0.4-fold (p < 0.01) of controls. Microscopic observation by Perls' staining revealed that the excessive iron accumulated in vesicular endosomal/lysosomal structures, which were substantially diminished by d-propranolol. We previously showed that propranolol could readily concentrate into the lysosomes and raise the intralysosomal pH; it is suggested that the lysosomotropic properties of d-propranolol retarded the EC iron accumulation and thereby conferred the protective effects against iron load-mediated cytotoxicity.     

Functional organization of perisylvian activation during presentation of sentences in preverbal infants

We examined the functional organization of cerebral activity in 3-month-old infants when they were listening to their mother language. Short sentences were presented in a slow event-related functional MRI paradigm. We then parsed the infant's network of perisylvian responsive regions into functionally distinct regions based on their speed of activation and sensitivity to sentence repetition. An adult-like structure of functional MRI response delays was observed along the superior temporal regions, suggesting a hierarchical processing scheme. The fastest responses were recorded in the vicinity of Heschl's gyrus, whereas responses became increasingly slower toward the posterior part of the superior temporal gyrus and toward the temporal poles and inferior frontal regions (Broca's area). Activation in the latter region increased when the sentence was repeated after a 14-s delay, suggesting the early involvement of Broca's area in verbal memory. The fact that Broca's area is active in infants before the babbling stage implies that activity in this region is not the consequence of sophisticated motor learning but, on the contrary, that this region may drive, through interactions with the perceptual system, the learning of the complex motor sequences required for future speech production. Our results point to a complex, hierarchical organization of the human brain in the first months of life, which may play a crucial role in language acquisition in our species.     

Role of KATP channels in sepsis

Sepsis is an infection-induced inflammatory syndrome responsible for approximately 10% of all deaths worldwide. While pathophysiological mechanisms remain to be fully unravelled, new insights and discoveries are yielding significant improvements in outcome, particularly in the high mortality conditions of shock and multi-organ failure. One potential target is the ATP-sensitive potassium (K(ATP)) channel, an ion channel critical to the cardiovascular stress response. Excessive activation of the vascular channel is now recognised as a major cause of hypotension and vascular hyporesponsiveness to catecholamines in septic shock. Some researchers advocate therapeutic blockade of these channels; however, outside the vasculature, channel opening may actually represent a protective mechanism against cellular damage. In this review we critically examine the role of the K(ATP) channel in sepsis.