Vascular supply of the anterior interventricular epicardial nerves and ventricular Purkinje fibers in the porcine hearts

Abstract

The aim of this study was to perform a pilot histological and quantitative analysis of the blood vessels accompanying the epicardial nerves (vasa nervorum) in the porcine hearts. Twenty healthy porcine hearts were used in this study. The blood vessels were analyzed by light microscopy using four different staining techniques in transverse sections taken from the upper, middle, and lower segments of the anterior part of the interventricular region and the adjacent parts of the right and left ventricles containing epicardial nerves and the endocardial peripheral parts of the Purkinje fibers. In total, 317 epicardial nerves were detected. The vasa nervorum were present in 75.7% of these nerves. The vasa nervorum resembled arterioles and postcapillary and collecting venules. One hundred and forty nine epicardial nerves were perivascular, located in the adventitia of the anterior interventricular artery and vein. The remaining 168 nerves ran freely through the epicardial interstitium. The presence of the vasa nervorum was not related to topographical location or nerve diameter. Additionally, from a total of 33 analyzed ventricular complexes of Purkinje fibers small blood vessels located in their proximity were identified in only two cases. It can be concluded that the majority of the anterior epicardial nerves of porcine heart possess well-developed vasa nervorum. In contrast, similar blood vessels are rarely present in the vicinity of the Purkinje fibers. The data obtained contribute to a better understanding of the nutrition of the cardiac nerves.

Vasa nervorum of epicardial nerves and valves of small veins investigated in porcine heart by two types of vascular injections

“…The high quality of the venous injections allowed accurate measurement of the thickness of the epicardial nerves in the individual segments. These results significantly contribute to previously published data about the topography and thickness of the subganglionic epicardial nerves (Batulevicius, Skripka, Pauziene, & Pauza, 2008;Pauza, Skripka, Pauziene, & Stropus, 2000;Pauziene et al, 2017;Stingl al., 2020).…”

“…However, due to technical reasons it was not possible to show the vasa nervorum of arterial or capillary type in specimens fixed in toto in formalin as these vessels course intraneurally. On the other hand, these intraneural vessels were seen in one of our previous studies (Stingl et al, 2020) as well as in histological analysis of this study. Direct evidence of the true existence of these vessels in our experiments is the fact that the India ink in all cases perfectly passed through all vascular structures, including capillaries, and thus completely visualized all microcirculatory components of the vasa nervorum.…”

“…In our study, the epicardial nerves and their branches are located within the adventitia of coronary arteries and veins or within a thin layer of interstitial tissue filling the space between the internal surface of the epicardium and the external surface of the myocardium. Furthermore, according to our own measurements, the epicardial nerves range in thickness from 15 to 380 μm (Stingl et al, 2020). Our hypothesis was that the architectonics of the vasa nervorum of these small nerves would be much simpler than that described in large nerves.…”

“…In the last published study, again performed on the same material from the previous studies, focused on the morphology of the anterior interventricular area, were detected and analyzed multiple vasa nervorum running alongside the epicardial nerves, both perivascular and coursing freely within the interstitium of the epicardial space (Stingl et al, 2020). The material used consisted of transverse sections through the upper, middle and lower segments of the anterior interventricular area.…”