Decreased Hepatic Nerve Fiber Innervation in Patients with Liver Cirrhosis

BACKGROUND/AIMS: Hepatic nerve innervation plays important roles in hepatic metabolism and hemodynamic mechanisms. We compared the distribution patterns of hepatic nerves between normal livers and two liver diseases to elucidate the effects of liver disease on the distribution of hepatic nerves. METHODS: Tissue specimens were obtained by ultrasonography-guided needle biopsies from 10 normal controls, 74 patients with chronic hepatitis (CH), and 35 patients with liver cirrhosis (LC). The obtained specimens were immunohistochemically stained using antibodies for S-100 protein and alpha-smooth-muscle actin (alpha-SMA). The degree of the expression in liver tissues was quantified by manual counting of positively stained nerve fibers under light microscopy. The serum hyaluronic acid level was assayed in all subjects to evaluate hepatic fibrosis. Electron microscopy examinations were also performed. RESULTS: The hepatic nerve innervation was significantly lower in LC than in normal controls, as indicated by S-100 protein staining. alpha-SMA and hyaluronic acid levels were higher in LC and CH than in normal controls. Electron microscopy revealed that unmyelinated nerve fiber bundles in the intralobar connective tissue coursed in the vicinity of hepatic triads. CONCLUSIONS: These results suggest that hepatic nerve innervation can be decreased by hepatic inflammatory responses and/or fibrotic changes in LC patients. Further study is needed to clarify this observation.

The Distribution and Innervation of the Extraocular Pulley Smooth Muscle in the Rat

PURPOSE: We evaluated the structure, distribution and innervation of the extraocular pulley smooth muscle in the rat, a species with a less complex visuomotor repertoire than primates. METHODS: The adult Sprague-Dawley rat was perfused transcardially with physiological saline followed by 4% formalin. The rat orbit was dissected en bloc, then paraffin processed and serially sectioned for hematoxylin-eosin and Masson's trichrome stain. The distribution and innervation of the extraocular pulley smooth muscle was confirmed by immunohistochemistry with human smooth muscle (SM) alpha-actin, tyrosine hydroxylase (TH) and neuronal nitric oxide synthase (nNOS). RESULTS: We found the pulley structure consist of focal condensations of eleastin and collagenous connective tissue in relationship to the rectus muscle in the equatorial Tenon's fascia. Especially, the pulley smooth muscle connected to medial rectus muscle was immunostained to TH and NOS. CONCLUSIONS: The data supports the presence of the extraocular pulley smooth muscle in the rat orbit supposing to have dopaminergic and nitroxidergic innervation.