Impact of chlorogenic acid on surface and phase properties of cholesterol-enriched phosphatidylcholine membranes.

This study analyses the insertion of Chlorogenic acid (CGA) in phosphatidylcholine (PC) membranes enriched with cholesterol (Chol). While cholesterol decreases the area per lipid and increases the dipole potential, CGA increases and decreases these values, respectively. When CGA is inserted into cholesterol-containing DMPC membranes, these effects cancel out, resulting in values that overlap with those of DMPC monolayers without Chol and CGA. The presence of CGA also compensates the increase of dipole potential produced by Chol which can be explain as a consequence of the orientation of CGA molecule at the interphase opposing the cholesterol dipole moieties and water dipoles. This compensatory effect is less effective when lipids lack carbonyl groups (CO). When monolayers are composed by unsaturated PCs the Chol compensation is found at higher concentrations of CGA due to the direct interaction between CGA and Chol. These results suggest that cholesterol modulates the interaction and distribution of CGA in the lipid membrane, which may have implications for its biological activity.

Water as a Link between Membrane and Colloidal Theories for Cells.

This review is an attempt to incorporate water as a structural and thermodynamic component of biomembranes. With this purpose, the consideration of the membrane interphase as a bidimensional hydrated polar head group solution, coupled to the hydrocarbon region allows for the reconciliation of two theories on cells in dispute today: one considering the membrane as an essential part in terms of compartmentalization, and another in which lipid membranes are not necessary and cells can be treated as a colloidal system. The criterium followed is to describe the membrane state as an open, non-autonomous and responsive system using the approach of Thermodynamic of Irreversible Processes. The concept of an open/non-autonomous membrane system allows for the visualization of the interrelationship between metabolic events and membrane polymorphic changes. Therefore, the Association Induction Hypothesis (AIH) and lipid properties interplay should consider hydration in terms of free energy modulated by water activity and surface (lateral) pressure. Water in restricted regions at the lipid interphase has thermodynamic properties that explain the role of H-bonding networks in the propagation of events between membrane and cytoplasm that appears to be relevant in the context of crowded systems.

Correlation between the hydration of acyl chains and phosphate groups in lipid bilayers: Effect of phase state, head group, chain length, double bonds and carbonyl groups.

This paper demonstrates by means of FTIR/ATR analysis that water molecules intercalate at different extents in the acyl chain region of lipid membranes in correlation with the hydration of the phosphate groups. This correlation is sensible to the chain length, the presence of double bonds and the phase state of the lipid membrane. The presence of carbonyl groups CO modifies the profile of hydration of the two regions as observed from the comparison of DMPC and 14:0 Diether PC. The different water populations in lipid interphases would give arrangements with different free energy states that could drive the interaction of biological effectors with membranes.

Modulación de marcadores de inflamación y estrés oxidativo en pacientes con diabetes tipo 1 y sobrepeso que participan en un programa de cambio de estilo de vida / Modulation of Inflammatory and oxidative stress markers in overweight type 1 Diabetes patients participating in a lifestyle change program

Introduction: Reduction in the expression of inflammatory markers and oxidative stress associated with exercise will protect against cardiovascular complications in Diabetes Mellitus (DM). Aim: The aim of this study was evaluated cardiovascular fitness (VO2 Max), interleukin-6 (IL-6), monocyte chemo-attractant protein 1 (MCP-1) and serum lipid peroxidation (TBARS) in overweight patients with Type-1 diabetes (T1DM) participating in a lifestyle-change program. Results: 20 T1DM overweight patients (43.3 ± 13.8 years), with BMI= 29.6 ± 3.5 kg/m2 , initial HbA1c 7.9 ± 0.91% and treated with multiple insulin injections, were included in this work. The lifestyle-change program consisted of: a) walking 10,000 steps/day, b) sequence of exercises of 24 minutes, 3-5 times/week, c) ¨healthy-plate¨ (and counting carbohydrates, and d) prandial insulin as blood-glucose levels. VO2 max, HbA1c, TBARS, IL6, MCP-1 were determined before starting the lifestyle-change program. Six months of adherence later, participants showed an average number of steps of 8242 ± 1834, a significant increase in VO2 max, (33.4 ±1.3 vs 36.2 ±1.5 ml.Kg-1.min-1 p= 0.008), a significant decrease in serum MCP-1 (314 ±42 vs 235 ±43 MFI p= 0.02), and less TBARS (3.01 ±0.44 vs 2.12 ±0.22 µmol/mL p= 0.015). IL-6 and HbA1c showed no significant decrease. Conclusion: Our results showed that a 6-month systemized and simple exercise plan improves cardiorespiratory fitness (VO2 max), and reduces both circulating oxidative stress and inflammation markers in overweight patients with T1DM.

Introducción: La reducción en la expresión de marcadores inflamatorios y de estrés oxidativo asociado con el ejercicio podría proteger contra las complicaciones cardiovasculares de la diabetes mellitus (DM). Objetivo: El objetivo de este estudio fue evaluar en pacientes con DM tipo1 (DMT1) y sobrepeso, la capacidad cardiorespiratoria (VO2 Max), la expresión sérica de marcadores inflamatorios (IL-6 y MCP-1) y la peroxidación lipídica sérica (TBARS), luego de participar por 6 meses de un programa de cambios de estilo de vida. Resultados: Veinte pacientes adultos (43.3 ± 13.8 años), de ambos sexos, con un Índice de Masa Corporal de 29.6 ± 3.5 kg/m2 , HbA1c inicial de 7,9% ± 0,91, en tratamiento con inyecciones múltiples de insulina participaron del estudio. Se indicó: 1) caminar 10.000 pasos/día, 2) realizar en domicilio una secuencia de ejercicios de 20 minutos, 3-5 veces/semana, 3) plato saludable (consumo de 1 fruta antes de las 3 comidas principales), 4) Insulina prandial según glucemia y conteo de carbohidratos. Se registraron parámetros antropométricos, presión arterial, se determinó VO2 max, y se midieron los niveles séricos de HbA1c, IL6, MCP-1 y TBARs. Luego de seis meses, los participantes alcanzaron un número promedio de pasos de 8242 ± 1834 y mostraron un aumento significativo en VO2 max, (33.4 ±1.3 vs 36.2 ±1.5 ml.Kg-1.min-1 p= 0.008). Además, se encontró una disminución significativa de MCP-1 (314 ±42 vs 235 ±43 MFI p=0.02) y TBARs (3.01 ±0.44 vs 2.12 ±0.22 µmol/mL p= 0.015) en comparación con el día 0. No se observaron modificaciones en los niveles de IL-6 y HbA1c. Conclusión: Nuestros resultados demuestran que el ejercicio, implementado como un plan accesible y acompañado, es adecuado para reducir los riesgos de inflamación y estado pro-oxidativo en pacientes con DM tipo1.

Vascular dysfunction elicited by a cross talk between periaortic adipose tissue and the vascular wall is reversed by pioglitazone.

AIM: Perivascular adipose tissue (PVAT) is in intimate contact with the vessel wall and extravascular PVAT-derived inflammatory mediators may adversely influence atherosclerotic plaque formation and stability through outside-to-inside signaling. We sought to investigate the role of PVAT on the atheroma development in an experimental animal model of metabolic syndrome (MS) associated with oxidative stress and low-grade inflammatory state. We also studied the effect of pioglitazone an insulin sensitizer, on the aortic wall and its surrounding PVAT, considering a bi-directional communication between both layers. METHODS: Apolipoprotein E-deficient mice (ApoE-/- ) were fed with standard diet (CD, control diet) or fructose overload (10% w/v) (FD, fructose diet) for 8 weeks and treated with or without pioglitazone the latest 4 weeks. RESULTS: Biochemical variables show that glycemia and lipid peroxidation determined by thiobarbituric acid reactive species (TBARS) significantly increased in FD-fed ApoE-/- mice. FD significantly increased aortic PVAT expression of oxidative stress associated genes: p22phox , Nox1, Nox2, Nox4 and p47phox , and proinflammatory genes: Visfatin, MCP-1, and MMP-9. Pioglitazone diminished PVAT-oxidative damage elicited by fructose treatment and markedly down-regulated proinflammatory markers. Even pioglitazone did not prevent the development of the aortic atheroma plaques stimulated by FD, significantly diminished VCAM-1 expression, MMP-9 expression and activity in aortic media wall and significantly reduced the accumulation of lipids and macrophages in atheroma plaques. CONCLUSION: Our results support the fact that PVAT contributes to the development and progression of cardiovascular disease by underlying mechanisms elicited by "outside-in" signaling. Treatment with pioglitazone may offer a new effect on the whole vessel wall, promoting the stability of advanced atherosclerotic plaques.