Neurovascular relationships in the human enteric nervous system

Objective: To demonstrate the existence of various morphological variants of neurovascular relationships in the human enteric nervous system. Materials and Methods. Autopsy fragments of the small and large intestines from newborns (n=9) and adults of first mature age (n=12) were studied using classical histological methods (hematoxylin and eosin staining, pararosaniline with toluidine blue, Azure II-eosin) and a modified universal method for impregnation of argyrophilic structures. The topography, morphology, and blood supply of ganglia of the myenteric and submucosal nerve plexuses were examined. Results. A modular principle of blood supply to ganglia and interganglionic cords of the human enteric nervous system was established. In newborns, 79% of ganglia are located within the lumen of lymphatic microvessels, and neurocyte nutrition is provided by lymph (neurolymphatic variant). In 21% of ganglia, a neurolymphohematic variant with blood microvessels was identified. In adults of first mature age, an extraneural microvascular bed with a network-type module functions (neurohematic variant). Microvascular modules of interganglionic nerve tracts are organized according to a magistral type with intra- and extraneural microvessels. Arteriovenular anastomoses and countercurrent gas exchangers were detected. Conclusion. At all stages of differentiation of enteric nervous system neurocytes in humans (neuroblast stage, growth stage, and maturation stage), corresponding morphological variants of neurovascular relationships function: interstitial, neurolymphatic, neurolymphohematic, and neurohematic, which ensures optimal conditions for differentiation and long-term stable survival of a heterogeneous population of neurocytes.