Cerebrovascular and brain microanatomy in spontaneously hypertensive rats with streptozotocin-induced diabetes.

The influence of hypertension associated with diabetes on cerebrovascular and frontal cortex or hippocampus microanatomy was investigated in 20-week-old spontaneously hypertensive rats (SHR) in which diabetes was induced by treatment with streptozotocin (STZ) and in control or STZ-diabetic age-matched normotensive Wistar Kyoto (WKY) rats. At the beginning of experiment, systolic pressure values were similar in WKY rats either control, or exposed to STZ and remarkably higher in control or STZ-treated SHR. Systolic pressure values increased in the different animal groups examined along the course of experiment. Blood glucose levels were increased in either STZ-WKY rats or -SHR compared to WKY rats and SHR respectively. The main changes occurring in pial and intracerebral arteries of SHR and STZ-SHR were thickening of the arterial wall accompanied by luminal narrowing. In medium sized pial arteries of STZ-WKY rats luminal narrowing and a decreased thickness of arterial wall were noticeable. Intracerebral arteries of STZ-WKY diabetic rats showed a not homogeneous sensitivity of different sized branches. The volume of zones III and IV of frontal cortex was decreased in SHR and STZ-SHR compared to control WKY rats. The number of nerve cells in these cerebrocortical layers was decreased to a similar extent in SHR. STZ-WKY rats or STZ-SHR compared to control WKY rats. In dentate gyrus, followed by the CA1 subfield of hippocampus, decreased volume and number of neurons were found in SHR and STZ-SHR compared to control WKY rats. The occurrence of astrogliosis was observed in hypertensive, diabetic or hypertensive plus diabetic rats. The above findings indicate the occurrence of cerebrovascular and brain microanatomical changes in SHR and to a lesser extent in STZ-diabetic rats compared to control normotensive and normoglicemic WKY rats. Association of hypertension and diabetes caused more pronounced changes than in the single disease models. These results support the view that hypertension and diabetes affect the structure of cerebrovascular tree and of brain and that association of the two diseases results in an increased risk of target-organ damage, involving brain.

Adipose tissue as an endocrine organ? A review of recent data related to cardiovascular complications of endocrine dysfunctions.

Clinical and experimental data obtained in the last few years have modified the concept of adipose tissue as one solely directed at energy storage and release. The adipose tissue is a target organ for glucocorticoids and several studies have been carried out on the function of hypothalamic-pituitary-adrenal axis in obese subjects without conclusive results. A recent and innovative finding is that adipose tissue can produce cortisol from its inactive precursor, cortisone. The identification of leptin, a hormone synthesised by fat tissue, has ushered in the modern view of this tissue as a true endocrine organ. Leptin is produced primarily by subcutaneous and to a lesser extent by visceral adipose tissue, and has a central role in controlling body weight and, especially in regulating fat stores. Leptin is also involved in several complex functions, including physiological processes associated with puberty. Another hormone of fat tissue is angiotensinogen, which is produced in larger amounts by visceral than subcutaneous fat. Human and animals adipose tissue express a whole renin-angiotensin system (RAS). Angiotensin II, the final effector of this system is probably produced locally by adipose tissue. The function of adipose RAS is not well known. RAS can participate together with other hormones and substances, in adipocyte differentiation and fat tissue growth, but could be also involved in the pathogenesis of complications of obesity including arterial hypertension.

Niveles de superóxido dismutasa y catalasa en enfermedades del anciano / Dismutase and catalase superoxide levels in pathologies of the elderly

Se han determinado los niveles de superóxido dismutasa (SOD) y catalasa (CAT) en 420 individuos de uno y otro sexo y edades comprendidas entre 50 y 93 años. De ellos, 126 que no mostraban ninguna enfermedad relevante se utilizaron como grupo control. Los 294 restantes mostraban diferentes trastornos: alteraciones del sistema vascular (insuficiencias coronarias, hipertensión, infarto, etc.), alteraciones del sistema osteoarticular (artritis, polialtralgias, osteoporosis, etc.), miomas, afecciones, prostáticas, enfermedad pulmonar obstructiva crónica (EPOC) y accidente cerebral vascular agudo (ACVA). Para valorar SOD se utilizó el método de minami y Yoshikawa y el método de Aebi para valorar CAT. Métodos estadísticos: ANOVA y "t" de Student. En la población control se han obtenido: 1) niveles de SOD y CAT más elevados en mujeres que en varones. 2) la actividad de CAT disminuye con la edad. En la población con patologías: 3) la actividad de SOD está elevada en cardiovascular, miomas, EPOC y ACVA. 4) la actividad de CAT desciende en cardiovascular, próstata, EPOC y ACVA. 5) en osteoarticular actividad normal de SOD y CAT, aunque SOD desciende con la edad, CAT desciende con la edad en cardiovascular y EPOC. En general el comportamiento de ambos enzimas tiende a conseguir un equilibrio en el sistema antioxidante