Taxonomic and Ethnical Dispersion of the Phenomenon of Pineal Concretions in the Gerontological Context

Abstract

The pineal gland (PG), or epiphysis, is involved in the organization of biological rhythms and adaptive reactions of the organism by the hormone melatonin. It is shown that various factors can influence the morphology and functional activity of the gland. Calcified concretions (corpora arenacea, brain sand) are unique biomineral structures of the PG; the causes of their formation and their possible functional significance have been unclear until now. To date, concrements have been found in four species of birds and 21 mammalian species, as well as in humans; they are absent in fish, amphibians, and reptiles. In this review, we have collected the available literature data on the composition, mechanisms of formation, and possible factors affecting the accumulation of concretions in the epiphysis. Although the generally accepted point of view is that the accumulation of pineal calcium deposits is age-dependent, the available data on PG mineralization lead to the conclusion that there is most likely a multifactorial mechanism of concrement formation. In addition, the nature and crystallinity of the inorganic tissue of the pineal concretions suggest that corpora arenacea, is a regulated and physiological type of petrification rather than a pathological type. The existence of contradictory data on the connection between the formation of brain sand and the change in the functional activity of the PG during seasonal endocrine changes and in the aging process requires the study of deposits and in-depth investigation.