Effects of Fat-Enriched Diet on the Content of Sphingolipids in the Brain and on Cognitive Functions in Old Rats

Long-term food restriction prevents aging-associated sphingolipid turnover dysregulation in the brain

Abnormalities of sphingolipid turnover in the brain during normal aging and age-related neurological disorders were associated with the neurons loss and cognitive malfunction. Calorie restriction (CR) prevented age-related deficits in hippocampal long-term potentiation and improved cognitive function at old age. In the paper we investigated the ceramide and sphingomyelin (SM) levels in the brain regions, which are critical for learning and memory of 3- and 24-month-old rats, as well as the correction of sphingolipid turnover in the brain of old rats, by means of the CR diet and modulators of SM turnover. Using the [methyl-(14)C-choline]SM, the neutral, but not the acid SMase activity has been observed to increase in both the hippocampus and brain cortex of 24-month-old rats with respect to 3-month-old animals. Age-dependent changes of neutral SMase activities were associated with ceramide accumulation and SM level drop in the brain structures studied. Treatment of the rats with the CR diet or N-acetylcysteine (NAC) or α-tocopherol acetate, but not an inhibitor of acid SMase imipramine, reduced the ceramide content and neutral SMase activity in the hippocampus of 24-month-old animals with respect to control rats of the same age. These results suggest that redox-sensitive neutral SMase plays important role in SM turnover dysregulation in both the hippocampus and neocortex at old age and that the CR diet can prevent the age-dependent accumulation of ceramide mainly via neutral SMase targeting.

Biogerontology in Ukraine: update

Recent biogerontological findings in Ukraine are critically reviewed. It is stressed that cooperation of efforts within and between departments, institutions and countries is an efficient mode of coping with the complex problems of aging. A wide spectrum of aging research was traditionally performed in state-funded institutions throughout the country, focusing primarily on the neuro-humoral regulation, immune system, adaptation, oxidative stress, comparative analysis and life span extension. Mitochondria and associated oxidative stress seem to be a crossroad of "wet" and in silico research traffics aimed underpinning mechanisms of aging and life span extension. For instance, the highest coefficients of determination of the mammalian maximum life span were associated with mitochondrial DNA base composition and insertions into the nuclear DNA (NUMTs). The main conclusions of the multidirectional investigative endeavors could concisely be described as: modifications of the mitochondrial membrane resulted in alterations in ROS generation, metabolism, and life span; coordinated action of the key antioxidant genes and enzymes is an important issue in successful aging; lateral hypothalamic area could be a morpho-functional center of anti-aging in CNS; lymphoid tissue microenvironment is crucial in determination of functionality of the transplanted cells; gene and polypeptide therapy proved to be a perspective approach in treatment of accelerated aging; artificial atmosphere with optimal gaseous composition could be an efficient mean for life span extension and viability enhancement.