Replacement of dietary fish oil by vegetable oils affects humoral immunity and expression of pro-inflammatory cytokines genes in gilthead sea bream Sparus aurata.

Commercial gilthead sea bream feeds are highly energetic, fish oil traditionally being the main lipid source. But the decreased fish oil production together with the increased prices of this oil encourages its substitution by vegetable oils, imposing new nutritional habits to aquaculture species. Partial replacement of fish oil by vegetable oils in diets for marine species allows good feed utilization and growth but may affect fish health, since imbalances in dietary fatty acids may alter fish immunological status. The effect of dietary oils on different aspects of fish immune system has been reported for some species, but very little is known about the effect of dietary oils on immune-related genes expression in fish. Thus, the objective of this study was to elucidate the role of dietary oils on the expression of two pro-inflammatory cytokines, Tumor Necrosis Factor-α (TNF-α) and Interleukine 1ß (IL-1ß) on intestine and head kidney after exposure to the bacterial pathogen Photobacterium damselae sp. piscicida. For that purpose, 5 iso-nitrogenous and iso-lipidic diets (45% crude protein, 22% crude lipid content) were formulated. Anchovy oil was the only lipid source used in the control diet (FO), but in the other diets, fish oil was totally (100%) or partially (70%) substituted by linseed (rich in n-3 fatty acids) or soybean (rich in n-6 fatty acids) (100L, 100S, 70L, 70S). Fish were fed experimental diets during 80 days and after this period were exposed to an experimental intestinal infection with the pathogen. Serum and tissue samples were obtained at pre-infection and after 1, 3 and 7 days of infection. RNA was extracted and cDNA was synthesized by reverse transcription from intestine and head kidney and the level expression of TNF-α and IL-1ß were assayed by using quantitative real time PCR. The expression level of genes analysed was represented as relative value, using the comparative Ct method (2(-ΔΔCt)). Serum anti-bacterial activity was measured as serum bactericidal capacity and lysozyme activity. Reduction of FO tends to reduce basal (pre-infection) genetic expression of both cytokines. However, complete FO replacement caused an over expression of both pro-inflammatory cytokines, particularly after 3 days of induced infection in fish fed soybean oil based diets. On the other hand, fish fed diets with low content of n-6 fatty acids showed better serum bactericidal capacity after infection, suggesting that the substitution of fish oil by vegetable oils containing high levels of n-6 fatty acids may induce imbalances on fish immune response, leading to a lower potential response against infections.

[Arterial hypertension and exercise]. / Hipertensión arterial y ejercicio.

Both dynamic and static exercise increase blood pressure in normotensive and hypertensive patients, but the change varies among these two main forms of exercise. The validity of the blood pressure response to acute exercise as a predictor for the future development of hypertension in normotensives, or of the degree of target organ damage in hypertensives is still not clear. This acute response could be an independent predictor of mortality or cardiovascular events in the normotensives. The postexercise hypotension could work as a beneficial mechanism to reduce the reduce the rise in pressure that occurs with time. While epidemiological studies suggest an inverse relationship between physical activity or fitness and blood pressure, longitudinal studies seem to confirm the hypotensive effect of dynamic aerobic training. Though possibly in a lesser degree, strength training has also been proved to be effective. Among the responsible mechanisms, a decrease in sympathetic nerve activity is most likely involved. Hypertension seems to be also associated with a lower maximal capacity, that could be even more adversely affected by the action of certain antihypertensive drugs such as diuretics or beta-blockers. All of these aspects have led to the acceptance of physical exercise among the non-pharmacological measures for the treatment of hypertension.

[Rehabilitation in the heart transplant patient]. / Rehabilitación en el paciente trasplantado de corazón.

Cardiac transplantation should not only enlarge life time but additionally should provide the patient with good quality of life and a satisfactory rehabilitation level. An integrated rehabilitation program can help to the process of recovery. In spite of the multiple factors which modify the physiological response during exercise, an appropriate training can be reached by many patients. Nevertheless the physiological rehabilitation is one of the components of the patients global restitution in order to reach satisfactory life style after transplantation.

[The importance of determining oxygen consumption in the indications for a heart transplant]. / Importancia de la determinación del consumo de oxígeno en las indicaciones del trasplante cardíaco.

Maximal exercise performance in patients with chronic heart failure, as determined by peak oxygen consumption (VO2max.) during exercise testing has been shown to correlate well with mortality and its use as primary determining factor in the selection of patients for heart transplant has been advocated. Patients with a VO2max of less than 14 ml/kg/min appear at particularly high risk for mortality. Exercise performance can be influenced by a number of independent factors including subject motivation, peripheral deconditioning or other intrinsic abnormalities of skeletal muscle, and primary respiratory disease. It appears to be a precise gauge of functional impairment. VO2max can be used to accurately and reproducibly place an individual in a predefined functional class.