Morphometric Analysis of Thoracic Ganglion Neurons in Subjects with and without Primary Palmar Hyperhidrosis

Background

Hyperhidrosis (HH) is a disease whose physiopathology remains poorly understood and that adversely affects quality of life. There is no morphologic study that includes an adequate control group that allows for comparison of the ganglion of HH to those of normal individuals. The purpose of study was to analyze morphologic and morphometric characteristics of the ganglion from patients with HH and normal individuals (organ donators).

Methods

This was a transversal study. The sympathetic thoracic ganglia were obtained from 2 groups of patients. Group PH (palmar hyperhidrosis), 40 patients with palmar HH submitted to surgery by video-assisted thoracoscopy, and group C (control group), 14 deceased individuals (control group of organ donators) without any history of HH. The third left sympathetic thoracic ganglion was resected in all patients.

Results

We observed higher number of cells in the PH group than in the control group (14.25 + 3.81 vs. 10.65 + 4.93) with P = 0.007; the mean percentage of ganglion cells stained by caspases-3 in the PH group was significantly greater than that of the C group (2.37 + 0.79 vs. 0.77 + 0.28) with P < 0.001; the mean value of area of collagen in the PH group was 0.80 IQ (0.08–1.87), and in the control group it was 2.36 IQ (0.49–5.98) with P = 0.061.

Conclusions

Subjects with primary palmar HH have a higher number of ganglion cells within the ganglion and a higher number of cells in apoptosis. Also, the subjects of PH group have less collagen in the sympathetic ganglion when compared with the control group, but not statistically significant.

Introduction

Hyperhidrosis (HH) is defined as excessive perspiration in nonphysiological situations1, 2 and a disease that adversely affects quality of life.³ Although its physiopathology remains poorly understood, it is most likely caused by a complex dysfunction within the autonomic nervous system.⁴ At present, sympathectomy is the most widely used form of treatment and is typically performed using the video-assisted thoracoscopy (VATS).5, 6, 7

Little is known about how the sympathetic ganglia govern perspiration in normal individuals or in those who have HH. Moura Junior et al.⁸ demonstrated in 2012 that, encephalic death does not affect the immunohistochemical (IHC) analysis of sympathetic ganglia, making them suitable for laboratorial scrutiny. That team went on to verify that the ganglia of the thoracic sympathetic chain are larger in primary HH subjects than those in normal individuals and that there is a heightened nerve activity, as demonstrated by the elevated expression of both acetylcholine and the α7 subunit of the acetylcholine receptor.⁹ Because no morphologic study includes a control group, thereby allowing a comparison between the ganglia of patients with HH and normal individuals (organ donors), the authors then compared the distribution of the α3 subunit in patients with palmar hyperhidrosis (PH) to that observed in normal individuals, finding that the α3 subunit expression is similar between the groups. The authors therefore concluded that the α3 subunit is not involved in the physiopathology of PH.

The purpose of this study was to analyze the morphologic and morphometric characteristics of the ganglion found in the sympathetic chain of the thorax in patients with PH. We set out to examine the form, size, number, and apoptosis rate at the cellular level and scrutinized the fibers belonging to the collagen/elastic system of the extracellular matrix. The control group consisted of non-HH subjects (organ donors).