A potential role for arginase in recurrent infections and hypertrophy of tonsillar and adenoidal tissue

Abstract

Since arginase has been found to be an arginine-depleting and nitric oxide synthase-regulating enzyme, the present study was devised to examine hypertrophied and infected tonsil and adenoid arginase activity in relation to a metabolic arginase-nitric oxide pathway and its association with disease processes. Tissues were taken from 32 children undergoing adenotonsillectomy. There was a statistically significant difference between the two tissue enzyme activities, with tonsillar arginase activity being higher than the corresponding adenoidal tissue (P < 0.005). This suggests a potential role for tissue arginase activity as an outcome module and a contributing factor in chronic recurrent infection and hypertrophy of tonsillar and adenoidal tissues.

The potential inflammatory role of arginase and iNOS in children with chronic adenotonsillar hypertrophy

“…Large concentrations of locally produced NO have several cytotoxic effects, including reaction with proteins and nucleic acids, suppression of mitochondrial respiratory chain or induction of cell necrosis and apoptosis [6,13]. Elgün et al [3], investigated the tissue arginase activities in tonsillar and adenoidal specimens from the patients with chronic adenotonsillar disease. They showed that tonsillar tissues had a significantly higher arginase activity per milligram tissue protein compared with the adenoidal tissues of the same patients.…”

“…They are synthesized in all eukaryotic cells from their immediate precursor, ornithine [16]. Another possible mechanism of adenotonsillar hypertrophy may be that elevated tissue arginase causes to the overproduction of ornithine and the formation of ornithine leads to production of polyamines [3]. Polyamines induce growth factors and cell proliferation [16].…”

“…Recent studies have demonstrated that arginase is induced by cytokines in several cell types, especially in macrophages at inflammatory sites [2]. Macrophage infiltration and activation are frequently found in chronic tonsillar inflammation [3]. Arginase is located in the cystosol and can compete with other cytosolic enzymes such as nitric oxide synthase (NOS) that use arginine as a common substrate [4].…”

“…Arginase contributes to wound healing by inhibiting NO production and increasing proline and polyamines [2]. The formation of polyamines leads to the hypertrophy of lymphoid tissue [3].…”

Enzymatic study of tonsil tissue alkaline and acid phosphatase in children with recurrent tonsillitis and tonsil hypertrophy

“…The proliferation and differentiation of B cells are enzymemediated events [11][12][13][14][15]. Enzyme tissue nonspecific alkaline phosphatase (TNAP) (orthophosphoric monoester phosphohydrolase, alkaline pH optimum E.C.…”