Immunopathologic co-localization of MPO, IgG, and C3 in glomeruli in human MPO-ANCA-associated glomerulonephritis.

Myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA)- associated glomerulonephritis (GN) is characterized by pauci-immune necrotizing glomerulonephritis(NGN). Although it has been thought that MPO-ANCA is involved in the pathogenesis of capillary injuries in NGN via activation of neutrophils, recent studies suggest a possible role of other factors such as immunoglobulins precipitated on the glomeruli. Here we performed a pathological study investigating a relationship of deposition of MPO, IgG, complements with regard to MPO-positive cells and glomerular capillaries in human MPO-ANCA-associated GN. Renal specimen including 317 glomeruli obtained from 20 patients with MPOANCA- associated GN were analyzed. All of the specimens showed significant focal segmental deposition of IgG. There was a significant glomerular infiltration of MPO-positive cells along with deposition of extracellular MPO in the active lesions of segmental and global NCG, with CD34 staining being decreased in the adjacent areas. IgG deposits were almost colocalized with C3 and partly with MPO, which are also associated with a decrease in CD34 staining, suggesting that immune complex formation and the resultant capillary injuries. Actually occurred, the colocalization of MPO, IgG and C3 was seen only in the glomerular lesions with low severity and activity. These results suggest that not only MPO itself released from the neutrophils but also immune complexes composed of MPO and anti-MPO antibody may play some pathogenetic roles for the glomerular injuries especially in the early phase of human MPO-ANCA-associated GN.

Candida albicans infection delays duodenal ulcer healing in cysteamine-induced duodenal ulcers in rats.

A low curability of ulcers infected with Candida has been reported in the literature. The aim of the study reported here was to investigate experimentally whether Candida infection affects the healing of ulcers. Candida albicans (the Candida group) or saline (the control group) was administered intragastrically into rats with a cysteamine-induced duodenal ulcer. The duodenal lesions, vascular endothelial growth factor A (VEGF-A) and proliferating cell nuclear antigen (PCNA) were assessed. On Day 7 post-administration, 70.4% rats of the Candida group had a duodenal ulcer compared with 33.3% in the control group (P < 0.05). The duodenal ulcer in the Candida group was significantly larger and deeper than that in the control group. The number of VEGF-A- and PCNA-positive cells was smaller and the area of VEGF-A expression was lower in the Candida group. Using a rat model, we have demonstrated that Candida infection can delay the wound healing process of duodenal ulcers by means of a low expression of VEGF-A and PCNA.

Intravenous injection of micafungin counteracts Candida albicans-induced aggravation of duodenal ulcers caused by cysteamine in rats.

BACKGROUND: We have reported previously that Candida albicans is involved in the pathogenesis of peptic ulcer perforation; it was shown that C. albicans aggravated the severity of duodenal ulceration and increased the rate of perforation. We considered it incumbent upon us to ascertain whether C. albicans is a virulence factor involved in peptic ulcer perforation. In the present study, we administered an antifungal drug (micafungin) intravenously to rats that had received intragastric (i.g.) administration of C. albicans and cysteamine, in order to examine that micafungin could counteract the C. albicans-aggravation of duodenal ulcers. METHODS: Cysteamine was administered thrice on day 1 to male Wistar rats. C. albicans was administered to the animals 1 h before, and 12 and 24 h after the first administration of cysteamine. Micafungin (n = 22) or saline (n = 24) was administered 12, 24, and 48 h after the administration of cysteamine. RESULTS: The area of the duodenal ulcers was also significantly smaller in the micafungin group (P < 0.05). In addition, the survival rate of the rats was significantly higher in the micafungin group (P < 0.05). While in the control group, the ulcer base was found to be colonized by C. albicans, there was no evidence of the presence of C. albicans in the micafungin group. CONCLUSION: It was shown that intravenous injection of micafungin counteracted the aggravation by C. albicans of cysteamine-induced duodenal ulcers in rats. This finding supports the concept that C. albicans is an aggravating factor for peptic ulcers.

Candida albicans aggravates duodenal ulcer perforation induced by administration of cysteamine in rats.

BACKGROUND: Candida sp are frequently isolated from the ascitic fluid of patients with perforated ulcers. The present study was performed to examine whether Candida infection may be involved in the process of ulcer perforation. METHODS: Male Wistar rats were divided into a saline group (n = 15) and a Candida group (n = 17). Cysteamine-HCl (Sigma; 31 mg/100 g) was administered thrice on day 1 to both groups of animals. Candida albicans at a density of 10(8) in 0.5 mL of saline was administered 1 h before, and 12 h and 24 h after the first administration of cysteamine in the Candida group. RESULTS: Perforated duodenal ulcers were observed in 94.1% of the rats in the Candida group, but only 26.7% of the rats in the saline group (P < 0.01). The area of the duodenal ulcers in the Candida group was 40.89 +/- 33.07 mm2, whereas that in the saline group was 16.53 +/- 20.4 mm2 (P < 0.05). The mortality rate was significantly higher in the Candida group than in the saline group. In the Candida group, colonization by C. albicans was recognized at the ulcer base, surrounded by marked granulocytic infiltration. The number of eosinophils infiltrating the ulcer base was also significantly greater in the Candida group than in the saline group. Immunohistochemical analysis revealed the expression of secretory aspartyl protease (SAP) in the region of the ulcer showing colonization by C. albicans in the Candida group. CONCLUSION: Candida albicans aggravates duodenal ulcer perforation in the experimental model of cysteamine-induced duodenal ulcer perforation. The present findings suggest that SAP and host-parasite relationships, including granulocyte-dependent mechanisms, may be involved in the aggravation of ulcer perforation by C. albicans.

A possible defensive mechanism in the basal region of gastric mucosa and the healing of erosions.

A possible defensive mechanism in the basal region of the gastric mucosa was hypothesized in the present study. In vivo microscopy was performed to observe the basal region after thermal injury to the back skin of rats. A donor of nitric oxide, 3-morpholinosydnonimine hydrochloride (SIN-1), or a serine protease inhibitor, camostat mesilate, was administered. Anti-vascular endothelial growth factor (VEGF) neutralizing antibody was administered 5 hours after thermal injury (anti-VEGF group). Post-capillary venules could be observed in the basal region of the gastric mucosa (PV-BGM). The PV-BGM was dilated 5 hours after thermal injury, and it was reduced by the administration of SIN-1 or pre-treatment with camostat mesilate. In the control group, the erosions did not reach the basal region of the gastric mucosa. Most of the erosions healed within 72 hours. Delayed healing was observed in the anti-VEGF group. In this group, exudation and congestion in the basal region were observed at 24 hours, and ulcer formation was observed at 72 hours after thermal injury. It is thus hypothesized that blood flow of the PV-BGM increases when superficial mucosal circulation is disturbed. The PV-BGM can contribute to defensive mechanisms in the basal region of gastric mucosa. The abnormal healing process may disturb the defensive mechanism at the base of the gastric mucosa, thereby resulting in ulcer formation.