Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The digestion of pancreatic tissue with collagenase is an essential part of the islet isolation procedure. However, the process exposes islets to various types of harmful factors, including collagenase contaminants, enzymes released from the acinar cells, warm ischemia, and mechanical agitation. Nitrogen oxide production and cytokine release may also contribute to islet cell damage. Protection of islets from such damage would improve the islet yield, survival, and function. Beraprost sodium (BPS) is a prostaglandin I2 analogue, is stable in aqueous solution, and has a cytoprotective effect on various types of cells. BPS has been shown to improve the yield and function of cryopreserved and/or cultured islets. These findings prompted us to examine its cytoprotective effect on islets during the islet isolation process. Canine islets were isolated by means of a two-step digestion method and purified on Euro-Ficoll density gradient solutions (the procedure used for human islets). BPS at a concentration of 100 nM was added to the collagenase solution. After purification, the islet yield was 434,561 +/- 35.691 islet number expressed as 150 microm equivalent size (IEQ)/pancreas or 8,799 +/- 345 IEQ/g of pancreas in the BPS group and 349,987 +/- 52,887 IEQ/pancreas or 7,998 +/-1610 IEQ/g of pancreas in the control group (n = 8, each). The percent viability was 88.5 +/- 0.7% in the BPS group and 82.0 +/-0.9% in the control group (P < 0.01). Therefore, the recovery of viable islets (calculated by islet number x % viability) was 384,586 +/- 46,804 IEQ/pancreas (7,743 IEQ/g) in the BPS group and 286,989 +/- 43,367 IEQ/pancreas (6,558 IEQ/g) in the control group (P < 0.02). After culture, significantly higher numbers of islets were also recovered in the BPS group than in the control group. The islet insulin content was significantly higher in the BPS group than controls (237.8 +/- 38.5 versus 92.3 +/- 25.6 microU/IEQ; P < 0.02), although islets of both groups responded with high stimulation indices (>6). These results indicate that the addition of BPS to the collagenase solution increases the recovery of viable islets, and improves beta cell function.
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PMID:Increased islet viability by addition of beraprost sodium to collagenase solution. 1145 Nov 49

The present studies were designed to investigate the sites of PGE(2), prostacyclin and leptin formation in human adipose tissue. Most of the PGE(2) and prostacyclin formation by adipose tissue explants from obese humans after 48 h in primary culture was due to blood vessels and other tissues not digested by collagenase. However, there was appreciable PGE(2) formation by adipocytes over a 48 h incubation and leptin formation was only seen in adipocytes. An increase in COX-2 immunoreactive protein was also seen after incubation of isolated human adipocytes for 48 h. The release of PGE(2) by adipocytes incubated for 48 h was about 4% that by intact adipose tissue explants while the release of prostacyclin was about 1.5% that by tissue. However, in a different experimental design where PGE(2) formation was measured over 2 h in the presence of 20 microM arachidonic acid the formation of PGE(2) by adipocytes after 48 h prior incubation in primary culture was 38% of that by tissue explants. Dexamethasone enhanced leptin release by adipocytes while inhibiting PGE(2) release and COX-2 up-regulation. The mechanisms involved in up-regulation of COX-2 activity during primary culture of adipocytes and the inhibition of this by dexamethasone do not appear to involve p38 MAPK or p42-44 MAPK. Interleukin I(beta) further enhanced PGE(2) formation by adipocytes but did not affect leptin formation. In conclusion, these data indicate that leptin release is exclusively a function of adipocytes while prostanoids are made by both adipocytes and the other cells present in human adipose tissue
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PMID:Comparison of PGE2, prostacyclin and leptin release by human adipocytes versus explants of adipose tissue in primary culture. 1246 69


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