Micro-anatomic distribution of peri-arterial renal sympathetic nerves

Abstract

Objective To investigate the distribution of sympathetic nerves around human renal arteries. Methods We collected 25 renal arteries from the patients who had a retroperitoneal laparoscopic nephrectomy and bilateral renal arteries from 7 human autopsy subjects. Each artery was equally divided into segments, which were made into paraffin sections. We examined the distribution of nerves around renal arteries and manually counted nerves by using optical microscope. Results A total of 3 065 nerves were identified from 258 sections. About 98% of all nerves existed within the renal arterial adventitia and the outside tissue. The mean number of nerves between the ventral, doirsal, superior, and inferior region of surgical specimens was 4.7±1.3, 1.4±0.7, 3.1±1.3, and 2.1±1.2, respectively. The mean number of nerves in the ventral region was greater compared with the doirsal region (P=0.000), the mean number of nerves in the superior region was also greater compared with the inferior region (P=0.005). The mean number of nerves in the middle segments was obviously greater compared with the distal segments (14.5±4.4 and 8.3±3.0, P=0.000). The mean number of nerves between the ventral, doirsal, superior, and inferior region of autopsy specimens was 5.4±1.4, 1.5±0.7, 3.1±0.8, and 2.8±1.0, respectively. The mean number of nerves in the ventral region was greater compared with the doirsal region(P=0.000), whereas the mean number of nerves was similar between the superior and inferior region (P=0.440). The mean number of nerves among the proximal, middle, and distal segments was 11.2±4.4, 17.6±4.4, and 8.5±2.2. It was obvious that the mean number of nerves in the middle segments was greater compared with the proximal and diatal segments (P=0.000). The distribution of sympathetic nerves around the left renal arteries was not considerably different compared with the right renal arteries (Psurgical=0.100, Pautopsy=0.916). Conclusion The mean number of nerves in the ventral region is greatest and least in the doirsal region. Along the renal artery, the distribution of nerves is relatively greater in the middle segments. Nerve anatomic distribution around the left renal arteries was not considerably different compared with the right renal arteries. Key words: Renal sympathetic denervation; Resistant hypertension; Renal artery; Sympathetic nerves; Anatomic distribution