Mediterranean Diet and Melatonin: A Systematic Review.

The Mediterranean diet (MD) has beneficial effects on human health, which is evidenced by the observation of lower incidence rates of chronic diseases in Mediterranean countries. The MD dietary pattern is rich in antioxidants, such as melatonin, which is a hormone produced mainly by the pineal gland and controls several circadian rhythms. Additionally, melatonin is found in foods, such as fruit and vegetables. The purpose of this systematic review was to assess the melatonin content in Mediterranean foods and to evaluate the influence of the MD on melatonin levels in both humans and model organisms. A comprehensive search was conducted in four databases (PubMed, Scopus, Cochrane Library and Web of Science) and data were extracted. A total of 31 records were chosen. MD-related foods, such as tomatoes, olive oil, red wine, beer, nuts, and vegetables, showed high melatonin contents. The consumption of specific MD foods increases melatonin levels and improves the antioxidant status in plasma.

Síndrome de osteoporosis pseudogliomatosa: asociación de ceguera con fracturas múltiples / Pseudogliomatous osteoporosis syndrome: association of blindness with multiple fractures

La osteoporosis primaria reúne un compendio de etiologías emergentes y puede ocurrir de forma sindrómica. La asociación de múltiples fracturas óseas con la presencia de pliegues retinianos congénitos debe orientar al diagnóstico del síndrome de osteoporosis-pseudogliomatosa. Se trata de un trastorno autosómico recesivo poco común, caracterizado por una osteoporosis grave y ceguera de aparición temprana. Las mutaciones de pérdida de función en el gen que codifica la proteína 5 relacionada con el receptor de lipoproteínas de baja densidad (LRP5) parece ser el causante de la aparición de esta enfermedad. Se presenta un caso de un niño con vítreo hiperplásico bilateral y antecedentes de fracturas cuyo estudio clínico, bioquímico y genético confirman el diagnóstico de esta inusual patología (AU)

Primary osteoporosis contains a compendium of emerging etiologies and can occur syndromically. The association of multiple bone fractures with the presence of congenital retinal folds should guide the diagnosis of osteoporosis-pseudogliomatous syndrome.It is a rare autosomal recessive disorder characterized by severe osteoporosis and early-onset blindness. Loss-of-function mutations in the gene encoding low-density lipoprotein receptor (LRP5), related protein 5 appear to be responsible for the onset of this disease.We present a case of a child with bilateral hyperplastic vitreous and a history of fractures whose clinical, biochemical and genetic studies confirm the diagnosis of this unusual pathology. (AU)

Melatonin as pharmacologic support in burn patients: a proposed solution to thermal injury-related lymphocytopenia and oxidative damage.

OBJECTIVE: To review the data that support the clinical use of melatonin in the treatment of burn patients, with special emphasis on the stimulation of the oxidative defense system, the immune system, circadian rhythm of sleep/wakefulness, and the reduction in the toxicity of therapeutic agents used in the treatment of burn victims. DATA SOURCE: A MEDLINE/PubMed search from 1975 to July 2006 was conducted. STUDY SELECTION: The screening of the literature was examined using the key words: burn patients, lymphocytopenia, skin oxidative stress, antioxidant, melatonin, and free radicals. DATA EXTRACTION AND SYNTHESIS: Thermal injury often causes damage to multiple organs remote from the original burn wound and may lead to multiple organ failure. Animal models and burn patients exhibit elevated free radical generation that may be causative in the local wound response and in the development of burn shock and distant organ injury. The suppression of nonspecific resistance and the disturbance in the adaptive immune system makes burn patients vulnerable to infections. Moreover, there is loss of sleep and the toxicity produced by drugs habitually used in the clinic for burn patients. Melatonin is a powerful antioxidant and is a potent protective agent against damage after experimental thermal injury. Some actions of melatonin as a potential supportive pharmacologic agent in burn patients include its: role as a scavenger of both oxygen and nitrogen-based reactants, stimulation of the activities of a variety of antioxidative enzymes, reduction in proinflammatory cytokines, inhibition of adhesion molecules, chronobiotic effects, and reduction in the toxicity of the drugs used in protocols to treat thermal injury patients. CONCLUSIONS: These combined actions of melatonin, along with its low toxicity and its ability to penetrate all morphophysiologic membranes, could make it a ubiquitously acting and highly beneficial molecule in burn patients.

Acutely administered melatonin is beneficial while chronic melatonin treatment aggravates the evolution of TNBS-induced colitis.

The aim of this study was to evaluate the effects of melatonin on the inflammatory response and hydroxyproline production in an experimental acute and chronic model of trinitrobenzene sulfonic (TNBS) acid-induced colitis in Wistar rats. In the acute model, melatonin (0.5, 1, and 2 mg/kg, i.p.) was applied 48, 24, and 1 hr prior to the induction of colitis and 24 and 48 hr after; the severity of colitis was less evident in melatonin-treated animals with significant response in the group treated with 2 mg/kg. All doses investigated significantly reduced the myeloperoxidase activity (MPO). In the chronic studies, melatonin (1 and 2 mg/kg, i.p.) was administered daily 24 hr before hapten instillation and for 7 or 21 days after TNBS; melatonin (2 mg/kg) worsened colitis evolution in the 21-day study with a significant increase in MPO activity and tumor necrosis factor-alpha production with respect to TNBS group. Histological slides were in concordance with macroscopic data where areas of extensive necrosis and edema, fibrosis, and absence of regenerated epithelium were observed. Moreover, the hydroxyproline determination, used as indicator of collagen production and fibrosis, also showed a marker increase. The results obtained in this experimental model showed that short-term administration is protective while in the long term it negatively influences evolution of inflammatory colitis; therefore, the immunostimulatory effect of melatonin in some situations when given chronically, such as during inflammatory bowel disease, might lead to negative consequences.