Morphological changes of porcine islets of Langerhans after collagenase and HBSS infusion of the pancreas

Background: A remarkable change in porcine islet morphology was observed after infusion of the pancreas with collagenase. The aim of the present study was to quantify these morphological changes and to assess whether these changes were due to the volume expansion caused by the collagenase entering the islet or the result of its digestive effects. Methods: This study was performed in pancreata of 28 crossbred pigs. First, eight pancreata were intraductally injected with collagenase by a continuous controlled pressure of 180 mmHg. Pancreas samples before collagenase infusion were used as controls. All tissue samples, both before and after infusion, were stained with anti-insulin. To quantify the morphological change of the islets, the mean beta cell/endocrine content ratio of the infused and not-infused tissue samples was compared. In a second experiment, 20 pancreata were similarly assessed after intraductal injection with Hank's balanced salt solution (HBSS). Results: In both the collagenase- and HBSS-infused groups, mean beta cell/endocrine content ratio was lower than in the control samples. The observed decline in the beta cell/endocrine content ratio was not significantly different between collagenase- and HBSS-infused pancreata. This suggests that the lower beta cell/endocrine content ratio and thus the morphological change in the infused tissue samples is caused by volume expansion of the fluid entering the islet and that the digestive effect of collagenase plays no or only a minor role. Conclusion: Morphological changes of islets are observed after infusion of pancreata with collagenase and HBSS, most likely caused by volume expansion due to fluid entering the islets.Analysis and support of clinical decision makin

Reduced Porcine Islet Isolation Yield in the Presence of Hyperemic Islets

When studying histological characteristics of porcine pancreata in relation to islet isolation, a remarkably high number of hyperemic islets (HIs) was encountered. The abnormalities observed in these HIs ranged from a single dilated vessel to hemorrhages extending into the surrounding exocrine tissue. The aim of the present study was to compare pancreata with and without HI on islet isolation outcomes. This study involved a histological examination of 143 purebred (74 juvenile and 69 adult) and 47 crossbred (only juvenile) porcine pancreata. Islet isolation was performed in 48 purebred adult pigs and in 25 crossbred pigs. Tissue samples were stained with Aldehyde Fuchsine. The presence of HIs was scored semi-quantitatively (HI-, HI+). We observed HIs in 48% of the purebred and in 68% of the crossbred pigs. However, only 3.3 +/- 3.1% and 3.1 +/- 4.7% of all assessed islets was hyperemic in HI+ pancreata in purebred and crossbred pigs, respectively. In both groups, significantly higher endocrine cell mass was found in the HI+ pancreata (p <0.01). When the higher endocrine cell mass was taken into account, we found significantly lower yields in the HI+ pancreata in both purebred and crossbred pigs (p = 0.03 in both groups). The presence of HIs occurs frequently in porcine donor-pancreata and is associated with reduced isolation outcomes

Reduced Porcine Islet Isolation Yield in the Presence of Hyperemic Islets

When studying histological characteristics of porcine pancreata in relation to islet isolation, a remarkably high number of hyperemic islets (HIs) was encountered. The abnormalities observed in these HIs ranged from a single dilated vessel to hemorrhages extending into the surrounding exocrine tissue. The aim of the present study was to compare pancreata with and without HI on islet isolation outcomes. This study involved a histological examination of 143 purebred (74 juvenile and 69 adult) and 47 crossbred (only juvenile) porcine pancreata. Islet isolation was performed in 48 purebred adult pigs and in 25 crossbred pigs. Tissue samples were stained with Aldehyde Fuchsine. The presence of HIs was scored semi-quantitatively (HI-, HI+). We observed HIs in 48% of the purebred and in 68% of the crossbred pigs. However, only 3.3 +/- 3.1% and 3.1 +/- 4.7% of all assessed islets was hyperemic in HI+ pancreata in purebred and crossbred pigs, respectively. In both groups, significantly higher endocrine cell mass was found in the HI+ pancreata (p <0.01). When the higher endocrine cell mass was taken into account, we found significantly lower yields in the HI+ pancreata in both purebred and crossbred pigs (p = 0.03 in both groups). The presence of HIs occurs frequently in porcine donor-pancreata and is associated with reduced isolation outcomes.Medical Decision MakingAnalysis and support of clinical decision makin

Presence of Hyperemic Islets in Human Donor-Pancreata Results in Reduced Islet Isolation Yield

When studying histological characteristics of human donor-pancreata, a remarkably high number of hyperemic islets (HIs) were encountered. The abnormalities in these HIs ranged from single/multiple dilated vessels to hemorrhages extending into the exocrine tissue. We aimed to determine the relevance of the presence of HIs in human donor-pancreata for isolation outcome and to identify donor and procurement factors associated with the occurrence of HIs. The presence of HIs was scored semi-quantitatively (HI-, HI+) in 102 human donor-pancreata. Islet isolation was performed in 40 cases. Donor and procurement factors were retrospectively analyzed in 94 donors. HIs were found in 54.6% of all donor-pancreata. However, only 4.5% of all islets in the affected pancreata was hyperemic. The affected pancreata contained slightly more endocrine tissue, but produced significantly lower yields. When corrected for other factors known to influence isolation outcome, the presence of HIs and endocrine content were the only factors significantly influencing isolation outcome. Prolonged ICU stay and pre-procurement hypertension were associated with the presence of HIs. This study is a first indication that the presence of HIs in human donor-pancreata are associated with reduced isolation outcomes and suggest an impact of the procurement procedure and pre-procurement hemodynamic status of the donor on the islet quality. It is tempting to speculate that this contributes to the generally experienced difficulties in obtaining sufficient amounts of human islets.Medical Decision MakingAnalysis and support of clinical decision makin