Tryptase in Acute Appendicitis: Unveiling Allergic Connections through Compelling Evidence

The aetiology of acute appendicitis (AA), the most frequent abdominal surgical emergency, is still unclarified. Recent epidemiologic, clinical and laboratorial data point to an allergic component in the pathophysiology of AA. Mastocytes participate in the Th2 immune response, releasing inflammatory mediators from their granules upon stimulation by IgE-specific antigens. Among the well-known mediators are histamine, serotonin and tryptase, which are responsible for the clinical manifestations of allergies. We conducted a prospective single-centre study to measure histamine and serotonin (commercial ELISA kit) and tryptase (ImmunoCAP System) concentrations in appendicular lavage fluid (ALF) and serum. Consecutive patients presenting to the emergency department with a clinical diagnosis of AA were enrolled: 22 patients with phlegmonous AA and 24 with gangrenous AA The control group was composed of 14 patients referred for colectomy for colon malignancy. Appendectomy was performed during colectomy. Tryptase levels were strikingly different between histological groups, both in ALF and serum (p < 0.001); ALF levels were higher than serum levels. Tryptase concentrations in ALF were 109 times higher in phlegmonous AA (APA) (796.8 (194.1-980.5) pg/mL) and 114 times higher in gangrenous AA (AGA) (837.4 (272.6-1075.1) pg/mL) than in the control group (7.3 (4.5-10.3) pg/mL. For the diagnosis of AA, the discriminative power of serum tryptase concentration was good (AUC = 0.825), but discriminative power was weak (AUC = 0.559) for the differential diagnosis between APA and AGA. Mastocytes are involved in AA during clinical presentations of both phlegmonous and gangrenous appendicitis, and no significant differences in concentration were found. No differences were found in serum and ALF concentrations of histamine and serotonin between histological groups. Due to their short half-lives, these might have elapsed by the time the samples were collected. In future research, these determinations should be made immediately after appendectomy. Our findings confirm the hypersensitivity type I reaction as an event occurring in the pathogenesis of AA: tryptase levels in ALF and serum were higher among patients with AA when compared to the control group, which is in line with a Th2 immune response and supports the concept of the presence of an allergic reaction in the pathogenesis of acute appendicitis. Our results, if confirmed, may have clinical implications for the treatment of AA.

Effects of a moderate physical training on the leptin synthesis by adipose tissue of adult rats submitted to a perinatal low-protein diet

The aim of the study was to verify if moderate physical training affects leptin content in visceral and subcutaneous adipose tissue of adult rats subjected to a low-protein diet during the perinatal period. Male Wistar rats were divided into 2 groups according to their mother's diet during gestation and lactation: control (17% casein, C, n=12) and low-protein (8% casein, LP, n=12). On postnatal day 60, half of each group was submitted to moderate physical training (8 wks, 5 d · wk - 1, 60 min · d - 1, at 70% of VO2max, T) or not. After the physical training period, visceral and subcutaneous adipose tissues were removed. Leptin content was evaluated by western blotting. Starting from the fifth week on, T pups showed a reduction in the body weight. Similarly, LP+T offspring showed a lower body weight starting from the sixth week on. Western blotting analysis showed that leptin content in the visceral tissue was higher in the LP rats (p<0.01) and it was reversed in LP+T. No difference was found in the subcutaneous tissue. Moderate physical training attenuated the effects of a perinatal low-protein diet on the leptin content in visceral adipose tissue in adult offspring.

Reinnervation of post-arthritic joints in the rat

OBJECTIVE

To clarify the role of articular innervation during the acute and post-arthritic phases, we investigated the changes taking place over time in the nerve fibers from joint tissues of adjuvant arthritic rats.

METHODS

Nerve densities (i.e., the number of nerve fibers observed per unit area of tissue section) were estimated in periarticular tissues, synovium and epiphysis from ankle joints. Nerves were identified by immunofluorescence microscopy using antibodies against general neuronal markers (Protein Gene Product 9.5, synaptophysin, neurofilaments and Schwann cells), and markers specific for either sensory or sympathetic nerves (Substance P, calcitonin gene related peptide, neuropeptide tyrosine and its C-terminal flanking peptide, and the catecholamine synthesising enzyme tyrosine hydroxilase).

RESULTS

In arthritic rats, the density of nerve fibers in the periarticular tissues, epiphysis and synovium was significantly reduced when compared to control animals. This decrease was observed using antibodies for both non releasable neuronal products (Protein Gene Product 9.5, synaptophysin, neurofilaments and Schwann cells) and neuropeptides (Substance P, calcitonin gene related peptide, neuropeptide tyrosine and its C-terminal flanking peptide), thus suggesting the existence of a structural nervous lesion with the parallel depletion of peptides. As the clinical arthritis subsided, there was a progressive reinnervation of all the articular structures analysed, which often exceeded the density of nerves in the control animals.

CONCLUSION

This work supports a close relationship between the nervous system and arthritis. We propose that cycles of nerve destruction and regeneration may be related to the characteristic periods of remission and activity of some forms of chronic arthritis.

[Diffuse tracheo-bronchial amyloidosis]

The case of a 52 year old man, whose initial clinical manifestations were dyspnea, bloodstained sputum and malaise is reported. After the initial cancer hypothesis, a diagnosis of diffuse primary tracheo-bronchial amyloidosis was made. The amyloid substance present was not of A A type and the plasma cells next to the deposits were polyclonal. The piece-meal removal of the masses by bronchoscopy led to profuse bleeding. The patient died with sepsis. The clinical, pathological and therapeutical aspects of lower respiratory tract amyloidosis are reviewed.