The central nervous system's involvement in the general control and coordination of organ, tissue, and even cell activities continues to pique researchers' interest. Significant evidence has recently been obtained in the field of new neurotransmitters and other active molecules, revealing the mechanisms of action and interactions. However, despite the fact that much is known about tiny pathways of afferent, efferent, and inter neuronal transmission, the role of the intra organ, local nervous system, and its relationships with the main brain and medullar centres remains a little mysterious.
Several scenarios were considered in order to separate the effect of the
intestine's central and intramural nervous systems: 1) surgical destruction of
nervous reflex connections (NRI), which is often present in organ
transplantation and often occurs in spinal cord trauma, and 2) injury of the
intramural nervous system with fully maintained links to the central nervous
system, such as after intestinal ischemia and in Hirschprung disease. A
surgical guided re innervation (SDR) of the intestinal graft by suture of the
divided mesenteric plexus was developed as a control. A model of ontogenetic
reconstruction of adult-like organs following syngeneic implantation into an
adult organism of a foetal organ with or without an organised intramural
nervous system (intestine, liver, pancreas) was also used.
The experiments on 101 dogs, 274 rodents, and 25 mice were carried out by the
same team in accordance with Bioethics guidelines.
Testing the nervous system's relation to the central nervous system (presence of the Recto-enteric reflex, natural response to anticholinergic substance), evaluating motility, secretion, and membrane digestion of the intestine, as well as optic and electron microscopy of the target organs were all carried out.
The following is a summary of the findings.The intrinsic functions and morphology of the intestine are not greatly affected by disconnection from the CNS for more than a few days (influence of operation trauma), but it has an effect on the own rhythm of the organ movement, which becomes "autonomous" and stops being incorporated into the overall control of digestive tract function. Accelerated nutrient transit, hypersecretion, and body weight loss are all symptoms. The activity of the remaining central nervous system-linked stomach and colon is altered in such a way that the final digestive process is adapted and realised correctly (central nervous coordinating intervention). Normalization of the controlled intestine's operation and the whole digestive process follows the restoration of central nervous reflex control.
The intestine's function and anatomy are also affected by the disruption of the intramural nervous system, which may occur as a result of chronic ischemia or congenital dysplasia. Only when a grafted foetal organ has an intramural nervous system will it complete its ontogenetic growth (for instance, intestine). If intra organ neurons are not organised as a plexus, graft production is incomplete and uncoordinated: only isolated, weakly organised structures form (for example, in the ectopically grown foetal liver - bile ducts, hepatocytes column, in the pancreas - isolated or clustered endocrine cells), with no connections between them.
So, while somatic nerve sutures are a common technique in reconstructive surgery of the face's limbs, surgical or guided reconstruction of nervous ties is virtually uncommon in solid organ grafting. Suturing the vegetative nervous plexus around the large vessel that irrigates the graft is theoretically easy and seems justified, but it probably still needs more studies to validate the benefits. These results may be useful in the future of organ transplantation, as it's possible to recover not only the graft's vascular connections with the host, but also the transplant's nervous connections with the recipient's central nervous system (brain and spinal medulla). On the one hand, this definition can be useful in the treatment of digestive problems in tetra and paraplegia patients, and on the other hand, Hirschprung disease. It can also be helpful to understand and comprehend issues that are either the result of central nervous system changes influencing digestion or, on the other hand, the development of extreme peripheral disorders affecting brain function.
Author (s) Details
V. ` Coulic
Laboratory of Experimental Medicine, Free Brussels University, Brussels, Belgium.
C. De Prez
Laboratory of Pathology, CHU Brugmann, Brussels, Belgium.
N. Iesuitova
Laboratory of Nutrition Physiology, Academy of Sciences, Sankt Petersburg, Russia.
L. F. Makarova
Laboratory of Organ and Tissue transplantation of the USSR Academy of Medicine, Moscow, Russia.
A. Maksimenkova
Laboratory of Organ and Tissue transplantation of the USSR Academy of Medicine, Moscow, Russia.
D. V. Mikhalski
CHU Erasme, Free Brussels University, Brussels, Belgium.
P. J. Delrée
IPG, Gosselies, Belgium.
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