Evolution of Enzyme Requirements for Human Islet Isolation

Abstract

Islet transplantation is becoming an established treatment option for managing a subset of adult patients who have type 1 diabetes mellitus. The success of this procedure is dependent upon the recovery of a sufficient number of functional human islets from donor organs for subsequent transplant. Here, the use of optimized bacterial collagenase-neutral protease enzyme mixtures has been shown to affect the yield and quality (defined by viability and glucose-stimulated insulin secretion) of islets recovered from human pancreata. However, few reports provide a systematic approach to correlate the biochemical characteristics or dose of collagenases and proteases to the recovery of functional islets. The focus of this review is to close this gap. The review summarizes five key advances toward an understanding of how Clostridium histolyticum collagenase and bacterial neutral proteases support the release of islets from human pancreata and key collagenase biochemical characteristics that lead to higher human islet yields. This information provides a foundation to develop a model of enzymatic tissue dissociation that can serve as a guide in assessing the effectiveness of collagenase or neutral protease enzymes used for human islet isolation. One key conclusion is the importance of excess amounts of collagen degradation activity in the islet isolation procedure to ensure

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“…In this work, we investigated the effect of several operating factors on the trypsin activity as our model protein to ensure that the SMART is suitable to process the proteins. The reaction of N-alpha-benzoyl-L-arginine ethyl ester with water in the presence of an equal amount of trypsin was observed over a certain time period by monitoring the optical density of the solution at 253 nm, and the relative activity was calculated using Equation (3) [ 69 ]. Figure 8 summarizes the results.…”

Islet Transplantation: How Much Have We Advanced and How to Keep Moving Forward?

“…This relevant work by Sharp et al challenges the notion that islet isolation techniques have 'reached their peak' and are unlikely to be amenable to substantial improvements. McCarthy et al [2] present an outstanding review striving to correlate biochemical characteristics or doses of collagenases and proteases to islet yields following an islet isolation. The authors provide a comprehensive framework of advances to foster an understanding of how collagenases and proteases enable the release of islets from the pancreas.…”