Arteriolar and venular oxygen tension distribution was studied in the subcutaneous connective tissue of the chamber window preparation in conscious Syrian golden hamsters as a function of the systemic PO2, PCO2, pH, arterial pressure and hematocrit, microvascular red blood cell (RBC) velocity, vessel diameter, and blood flow in the same microvessels. PO2 was measured with the phosphorescence decay technique using Pd-meso-tetra(4-carboxyphenyl)porphyrin (30 mg/kg body wt iv). Systemic arterial and venous PO2s were 71.6 +/- 13.1 and 28.4 +/- 5.1 mmHg, while oxygen tension was 45.1 +/- 13.3 mmHg in arterioles and 30.1 +/- 10.7 mmHg in venules. The relatively low arteriolar PO2 and the small arteriolar-venular PO2 gradient indicate that some blood oxygen exits directly to the tissue or is shunted before reaching the capillaries. RBC velocity was the strongest correlate of microvascular PO2 (arterial correlation coefficient = 0.503 and venous correlation coefficient = 0.560, P < 0.001). Microvascular PO2 was also correlated with blood flow, vessel diameter, blood pH, and PCO2 but not with systemic PO2. Arterial oxygen tension was only significantly related to PCO2, pH, and hematocrit. These findings suggest that oxygen delivery to the tissue improves with increasing blood flow velocity and that microvascular PO2 is a locally regulated parameter in the absence of major systemic perturbations.

Epidemiological studies have shown a correlation between flavonoid-rich diets and improved cardiovascular prognosis. Cocoa contains large amounts of flavonoids, in particular flavanols (mostly catechins and epicatechins). Flavonoids possess pleiotropic properties that may confer protective effects to tissues during injury. We examined the ability of epicatechin to reduce short-and long-term ischemia-reperfusion (I/R) myocardial injury. Epicatechin (1 mg.kg(-1).day(-1)) pretreatment (Tx) was administered daily via oral gavage to male rats for 2 or 10 days. Controls received water. Ischemia was induced via a 45-min coronary occlusion. Reperfusion was allowed until 48 h or 3 wk while Tx continued. We measured infarct (MI) size (%), hemodynamics, myeloperoxidase activity, tissue oxidative stress, and matrix metalloproteinase-9 (MMP-9) activity in 48-h groups. Cardiac morphometry was also evaluated in 3-wk groups. With 2 days of Tx, no reductions in MI size occurred. After 10 days, a significant approximately 50% reduction in MI size occurred. Epicatechin rats demonstrated no significant changes in hemodynamics. Tissue oxidative stress was reduced significantly in the epicatechin group vs. controls. MMP-9 activity demonstrated limited increases in the infarct region with epicatechin. By 3 wk, a significant 32% reduction in infarct size was observed with Tx, accompanied with sustained hemodynamics and preserved chamber morphometry. In conclusion, epicatechin Tx confers cardioprotection in the setting of I/R injury. The effects are independent of changes in hemodynamics, are sustained over time, and are accompanied by reduced levels of indicators of tissue injury. Results warrant the evaluation of cocoa flavanols as possible therapeutic agents to limit ischemic injury.

Objectives We examined the effects of the flavanol (−)-epicatechin on short and long-term infarct size and left ventricular (LV) structure/function after permanent coronary occlusion (PCO) and the potential involvement of the protective AKT/ERK signaling pathways. Background (−)-Epicatechin reduces blood pressure in hypertensive patients and limits infarct size in animal models of myocardial ischemia-reperfusion injury. However, nothing is known about its effects on infarction after PCO. Methods (−)-Epicatechin (1mg/kg/day) treatment (Tx) was administered via daily oral gavage to 250 g male rats for 10 days prior to PCO and continued afterwards. PCO controls received water. Sham animals underwent thoracotomy and treatment in the absence of PCO. Immunoblots assessed AKT/ERK involvement 2 h after PCO. LV morphometry and function were measured 48 h and 3 weeks post-PCO. Results In the 48 h group, Tx reduced infarct size by 52%. There were no differences in hemodynamics amongst the different groups (heart rate, aortic and LV pressures). Western blots revealed no differences in AKT or ERK phosphorylation levels. At 3 weeks, PCO control animals demonstrated significant increases in LV end-diastolic pressure, heart weight/body weight, and LV chamber diameter vs. sham. PCO + (−)-epicatechin group values were comparable to sham + (−)-epicatechin. Tx resulted in a 33% decrease in MI size. LV pressure-volume curves demonstrated a right shift in control PCO animals, whereas (−)-epicatechin were comparable to sham. LV scar area strains were significantly improved with (−)-epicatechin. Conclusions These results demonstrate the unique capacity of (−)-epicatechin to confer cardioprotection in the setting of a severe form of myocardial ischemic injury. Protection is sustained over time and preserves LV structure/function. The cardioprotective mechanism(s) of (−)-epicatechin appear unrelated to AKT or ERK activation. (−)-Epicatechin warrants further investigation as a cardioprotectant.

Haematopoietic cell transplant activity in the 28 countries comprising Latin America is poorly defined. We conducted a voluntary survey of members of the Latin American Bone Marrow Transplantation Group regarding transplant activity 2009-2012. Collated responses were compared with data of transplant rates from the Worldwide Network for Blood and Marrow Transplantation for other geographic regions. Several socio-economic variables were analysed to determine correlations with transplant rates. In total, 94 teams from 12 countries reported 11 519 transplants including 7033 autotransplants and 4486 allotransplants. Annual activity increased from 2517 transplants in 2009 to 3263 in 2012, a 30% increase. Median transplants rate (transplant per million inhabitants) in 2012 was 64 (autotransplants, median 40; allotransplants, median 24). This rate is substantially lower than that in North America and European regions (482 and 378) but higher than that in the Eastern Mediterranean and Asia Pacific regions (30 and 45). However, the Latin America transplant rate is 5-8-fold lower than that in America and Europe, suggesting a need to increase transplant availability. Transplant team density in Latin America (teams per million population; 1.8) is 3-4-fold lower than that in North America (6.2) or Europe (7.6). Within Latin America, there is substantial diversity in transplant rates by country partially explained by diverse socio-economic variables including per capita gross national income, health expenditure and physician density. These data should help inform future health-care policy in Latin America.