Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction

To date, three isoforms of phospholipase A2 (PLA2) have been identified. Of these, the two Ca2+-dependent isoforms, secretory (sPLA2) and cytosolic phospholipase A2 (cPLA2), are targets for new anti-inflammatory drugs. The catalytic mechanisms and functions of the third isoform, Ca2+-independent cytosolic phospholipase A2 (iPLA2), are unknown at present. sPLA2 and cPLA2 are both implicated in the release of arachidonic acid and prophlogistic lipid mediators. However, recent findings provide evidence that cPLA2 is the dominant isoform in various kinds of inflammation, such as T-cell-mediated experimental arthritis. A triple function of PLA2-derived lipid mediators has been suggested: causing immediate inflammatory signs, involvement in secondary processes, e.g., superoxide free radical (O2) generation, apoptosis, or tumour necrosis factor-alpha (TNF-alpha)-cytotoxicity, and controlling the expression and activation of pivotal proteins implicated in inflammation and cell development, e.g., cytokines, adhesion proteins, proteinases, NF-kappaB, fos/jun/AP-1, c-Myc, or p21ras. In the past, research predominantly focused on the development of sPLA2 inhibitors; however, present techniques enable discrimination of cPLA2, sPLA2, and iPLA2, and specific inhibitors of each of the three isoforms are likely to appear soon. Over the last decade, between 40 and 50 sPLA2 inhibitors have been described; and the list is growing. However, of these, few have the potential for clinical success, and those that do are predominantly active site-directed inhibitors, e.g., BMS-181162, LY311727, ARL-67974, FPL67047, SB-203347, Ro-23-9358, YM-26734, and IS-741. At present, there are no likely clinical candidates emerging from the ranks of cPLA2 and iPLA2 inhibitors in development. Indications for which PLA2 inhibitors are being pursued include, sepsis, acute pancreatitis, inflammatory skin and bowel diseases, asthma, and rheumatoid arthritis. The three main obstacles to the successful development of PLA2 inhibitors include, insufficient oral bioavailability, low affinity for the enzyme corresponding to low in vivo efficacy and insufficient selectivity.

Phospholipase A2 inhibitors in development.

In Japan and China, Oren-gedoku-to (a complex mixture of ingredients derived from plants) has been used as a herbal medicine in the treatment of inflammatory and ulcerative diseases. In other countries salicylazosulfapyridine has been used to treat inflammatory bowel disease. In this study, we have compared the effect of Oren-gedoku-to with salicylazosulfapyridine on trinitrobenzene-sulphonic acid-induced colonic damage in rats, a model representative of ulcerative colitis and Crohn's disease in man. Oren-gedoku-to was administered orally for one or two weeks over a range of doses. Tissue damage scores, body weight, spleen weight, colon wet weight and colon wall thickness were measured, and colonic tissue levels of interleukin-8 (IL-8), leukotriene B4 (LTB4), prostaglandin E2 (PGE2), and myeloperoxidase activity were examined. The results indicated that Oren-gedoku-to was effective in the treatment of inflammatory bowel disease in the rat model. Histological observation showed a quicker healing process of the lesions, and a reduction of inflammatory cell infiltration following administration of Oren-gedoku-to. The precise mechanism of action for Oren-gedoku-to is still unclear; however, the reduction of IL-8, LTB4, and PGE2 observed suggests that the mechanism may be different from salicylazosulfapyridine (which has no effect on IL-8). There may be a potential benefit in offering combination therapy for the treatment of inflammatory bowel disease.

The effect of Oren-gedoku-to on experimental colitis in rats.

Forty-seven-year-old woman with Sjogren’s syndrome had been operated on because of transsphincteric perianal fistula secondary to perianal abscess. Vaginal wall injury occurred during the course of the operation and injured tissue was repaired primarily. Three months later, patient suffered from the recurrence of perianal fistula symptoms and fistulectomy was performed once again under antibiotic suppression. Several months later, perineal discharge continued, and, therefore, patient was admitted to the hospital for the third time and a fistulotomy was performed. Two months after the third operation, patient was admitted with leukorrhea and a perineovaginal fistula was detected. This time, not only her surgical problem but also her immune system disorder was considered in the preoperative workup. Then, patient was hospitalized for the fourth time and “fistulectomy/perineoplasty” was performed successfully. We believe that patients with autoimmune disorders with or without medical treatment may have healing problems during the course of surgical processes and therefore such medical problems must be taken into consideration by the surgeons.

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Vaginoperineal Fistula as a Complication of Perianal Surgery in a Patient with Sjögren's Syndrome: A Case Report.

A new water-soluble, orally absorbable de-N-acetyl-lysoganglioside (WILD20), breakdown product of the monosialoganglioside GM1, was found to influence some parameters of neutrophil response to inflammation stimuli. Superoxide anion production appears inhibited, along with neutrophil killing properties. A block of both pathways of arachidonic acid cascade and PAF was also found, as well as neutrophil ICAM-1-mediated adhesion to endothelial cells. Of particular interest was the significant reduction of neutrophils observed at the site of inflammation, whichever agonist was used. The effects on neutrophil physiology found in normal or in pathological conditions, are in favour of a WILD20-related inhibitory effect on neutrophil contribution to inflammation.

In vitro and in vivo impact of a new glycosphingolipid on neutrophils

A new, orally active de-N-acetylated lysoglycosphingolipid (WILD20) was evaluated as antiinflammatory agent using a model of chemically-induced inflammatory bowel disease (IBD) in the rat to mimic human ulcerative colitis and Chron's disease. IBD was induced by hapten trinitrobenzenesulphonic acid (TNB). WILD20, orally administered as preventive or curative, was demonstrated to be efficacious at daily dosages of 0.1–1 mg/kg for 4–5 days. Damage scores, body weight, spleen weight, colonic tissular levels of LTB4, myeloperoxidase (MPO) and malondialdehyde (MDA) are influenced and brought into parameters of normality.

A. Modesti

Papers

Effect of a new De-N-acetyl-lysoglycosphingolipid on chemically-induced inflammatory bowel disease: possible mechanism of action