360-OR: BETA-2 Score Is Highly Correlated with Acute Insulin Response to Intravenous Glucose: An Analysis of the Clinical Islet Transplantation Consortium Trials

Although human islet transplantation has been established as valid and safe treatment for patients with type 1 diabetes, the utilization rates of human pancreases for clinical islet transplantation are still limited and substantially determined by the quality and composition of collagenase blends. While function and integrity of collagenase has been extensively investigated, information is still lacking about the most suitable supplementary neutral proteases. The present study compared islet isolation outcome after pancreas digestion by means of collagenase used alone or supplemented with either neutral protease (NP), clostripain (CP), or both proteases. Decent amounts of islet equivalents (IEQ) were isolated using collagenase alone (3090 ± 550 IEQ/g), or in combination with NP (2340 ± 450 IEQ/g) or CP (2740 ± 280 IEQ/g). Nevertheless, the proportion of undigested tissue was higher after using collagenase alone (21.1 ± 1.1%, P < 0.05) compared with addition of NP (13.3 ± 2.2%) or CP plus NP (13.7 ± 2.6%). Likewise, the percentage of embedded islets was highest using collagenase only (13 ± 2%) and lowest adding NP plus CP (4 ± 1%, P < 0.01). The latter combination resulted in lowest post-culture overall survival (42.7 ± 3.9%), while highest survival was observed after supplementation with CP (74.5 ± 4.8%, P < 0.01). An insulin response toward glucose challenge was present in all experimental groups, but the stimulation index was significantly decreased using collagenase plus NP (2.0 ± 0.12) compared with supplementation with CP (3.16 ± 0.4, P < 0.001). This study demonstrates for the first time that it is possible to isolate significant numbers of human islets combining collagenase only with CP. The supplementation with CP is an effective means to substantially reduce NP activity, which significantly decreases survival and viability after culture. This will facilitate the manufacturing of enzyme blends with less harmful characteristics.

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Two nights of recovery sleep restores the dynamic lipemic response, but not the reduction of insulin sensitivity, induced by five nights of sleep restriction

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00336.2018 ◽

2019 ◽

Vol 316 (6) ◽

pp. R697-R703 ◽

Cited By ~ 4

Author(s):

Kelly M. Ness ◽

Stephen M. Strayer ◽

Nicole G. Nahmod ◽

Anne-Marie Chang ◽

Orfeu M. Buxton ◽

...

Keyword(s):

Insulin Sensitivity ◽

Insulin Response ◽

Sleep Restriction ◽

Nonesterified Fatty Acid ◽

Acute Insulin Response ◽

Intravenous Glucose ◽

Recovery Sleep ◽

Time In Bed ◽

Increased Risk ◽

Insulin Response To Glucose

Chronic inadequate sleep is associated with increased risk of cardiometabolic diseases. The mechanisms involved are poorly understood but involve changes in insulin sensitivity, including within adipose tissue. The aim of this study was to assess the effects of sleep restriction on nonesterified fatty acid (NEFA) suppression profiles in response to an intravenous glucose tolerance test (IVGTT) and to assess whether 2 nights of recovery sleep (a “weekend”) is sufficient to restore metabolic health. We hypothesized that sleep restriction impairs both glucose and lipid metabolism, specifically adipocyte insulin sensitivity, and the dynamic lipemic response of adipocyte NEFA release during an IVGTT. Fifteen healthy men completed an inpatient study of 3 baseline nights (10 h of time in bed/night), followed by 5 nights of 5 h of time in bed/night and 2 recovery nights (10 h of time in bed/night). IVGTTs were performed on the final day of each condition. Reductions in insulin sensitivity without a compensatory change in acute insulin response to glucose were consistent with prior studies (insulin sensitivity P = 0.002; acute insulin response to glucose P = 0.23). The disposition index was suppressed by sleep restriction and did not recover after recovery sleep ( P < 0.0001 and P = 0.01, respectively). Fasting NEFAs were not different from baseline in either the restriction or recovery conditions. NEFA rebound was significantly suppressed by sleep restriction ( P = 0.01) but returned to baseline values after recovery sleep. Our study indicates that sleep restriction impacts NEFA metabolism and demonstrates that 2 nights of recovery sleep may not be adequate to restore glycemic health.

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Prostaglandin synthesis inhibitors reverse alpha-adrenergic inhibition of acute insulin response to glucose

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1980.239.6.e490 ◽

1980 ◽

Vol 239 (6) ◽

pp. E490-E500 ◽

Cited By ~ 1

Author(s):

S. A. Metz ◽

R. P. Robertson

Keyword(s):

Basal Insulin ◽

Sodium Salicylate ◽

Insulin Response ◽

Prostaglandin Synthesis ◽

Prostaglandin E ◽

Acute Insulin Response ◽

Adrenergic Stimulation ◽

Intravenous Glucose ◽

Prostaglandin Synthesis Inhibitors ◽

Glucose Pulse

Prostaglandin E (PGE) has several effects on glucose homoeostasis and insulin secretion. The same events can be induced by alpha-adrenergic stimulation, which is known to stimulate PGE synthesis. To evaluate the hypothesis that PGE may be one intracellular mediator for certain alpha-adrenergic events, we examined the effects of a known PG synthesis inhibitor Sodium salicylate (SS) (40 mg/min iv) on the alpha-adrenergic effects of epinephrine (Epi) at two doses (3 and 6 micrograms/min) in normal male subjects. The lower dose of epinephrine diminished the acute insulin response (AIR) after a 20-g intravenous glucose pulse (control, 463 +/- 149; epinephrine, 97 +/- 38% of basal insulin, mean +/- SE, n = 6, P < 0.02); SS markedly augmented the AIR during epinephrine towards control values (339 +/- 137%; P < 0.02). In 12 subjects, the higher dose of Epi abolished the AIR. When similar studies were performed during a SS infusion, the AIR was partially restored (96 /+- 27% of basal insulin, n = 12, P < 0.01). Similarly, partial reversal of this alpha-adrenergic effect of Epi was observed with indomethacin, another inhibitor of PG synthesis. At both doses of Epi, SS augmented the glucose disappearance rate (KG) after the glucose pulse (P < 0.001). Sodium salicylate also increased basal glucagon levels (P < 0.05). In contrast, SS did not affect the glycemic response, the suppression of basal insulin levels, or the hemodynamic responses induced by adrenergic stimulation. We conclude that two prostaglandin synthesis inhibitors partially reverse the alpha-adrenergic inhibition of the AIR to glucose caused by Epi, without affecting other adrenergic events. The data are compatible with a role for prostaglandins in alpha-adrenergic events selectively in the pancreatic islet.

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Effects of prolonged fasting and sustained lipolysis on insulin secretion and insulin sensitivity in normal subjects

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.90613.2008 ◽

2009 ◽

Vol 296 (3) ◽

pp. E454-E461 ◽

Cited By ~ 18

Author(s):

B. Salgin ◽

M. L. Marcovecchio ◽

S. M. Humphreys ◽

N. Hill ◽

L. J. Chassin ◽

...

Keyword(s):

Insulin Secretion ◽

Insulin Sensitivity ◽

Insulin Response ◽

Random Order ◽

Intravenous Glucose Tolerance Test ◽

Disposition Index ◽

Acute Insulin Response ◽

Intravenous Glucose ◽

Family History Of Diabetes ◽

Prolonged Fast

Normal β-cells adjust their function to compensate for any decrease in insulin sensitivity. Our aim was to explore whether a prolonged fast would allow a study of the effects of changes in circulating free fatty acid (FFA) levels on insulin secretion and insulin sensitivity and whether any potential effects could be reversed by the antilipolytic agent acipimox. Fourteen (8 female, 6 male) healthy young adults (aged 22.8–26.9 yr) without a family history of diabetes and a body mass index of 22.6 ± 3.2 kg/m2 were studied on three occasions in random order. Growth hormone and FFA levels were regularly measured overnight (2200-0759), and subjects underwent an intravenous glucose tolerance test in the morning (0800-1100) on each visit. Treatment A was an overnight fast, treatment B was a 24-h fast with regular administrations of a placebo, and treatment C was a 24-h fast with regular ingestions of 250 mg of acipimox. The 24-h fast increased overnight FFA levels (as measured by the area under the curve) 2.8-fold [51.3 (45.6–56.9) vs. 18.4 (14.4–22.5) *104 μmol/l*min, P < 0.0001], and it led to decreases in insulin sensitivity [5.7 (3.6–8.9) vs. 2.6 (1.3–4.7) *10−4 min−1 per mU/l, P < 0.0001] and the acute insulin response [16.3 (10.9–21.6) vs. 12.7 (8.7–16.6) *102 pmol/l*min, P = 0.02], and therefore a reduction in the disposition index [93.1 (64.8–121.4) vs. 35.5 (21.6–49.4) *102 pmol/mU, P < 0.0001]. Administration of acipimox during the 24-h fast lowered FFA levels by an average of 20% (range: −62 to +49%; P = 0.03), resulting in a mean increase in the disposition index of 31% ( P = 0.03). In conclusion, the 24-h fast was accompanied by substantial increases in fasting FFA levels and induced reductions in the acute glucose-simulated insulin response and insulin sensitivity. The use of acipimox during the prolonged fast increased the disposition index, suggesting a partial reversal of the effects of fasting on the acute insulin response and insulin sensitivity.

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Evaluation of a Purified Enzyme Blend for the Recovery and Function of Canine Pancreatic Islets

Cell Transplantation ◽

10.1177/096368979800700404 ◽

1998 ◽

Vol 7 (4) ◽

pp. 365-372 ◽

Cited By ~ 25

Author(s):

Jonathan R.T. Lakey ◽

Thomas J. Cavanagh ◽

Michael A.J. Zieger ◽

Mary Jo Wright

Keyword(s):

Islet Transplantation ◽

Stimulation Index ◽

Insulin Response ◽

Canine Model ◽

Preclinical Model ◽

Islet Isolation ◽

Clinical Islet Transplantation ◽

Type V ◽

And Function

Recently developed technologies enabling the production of a reproducible, purified enzyme blend for optimal human pancreatic islet isolation has renewed interest in clinical islet transplantation. The canine model has been an ideal preclinical model for the development of islet transplantation protocols. As seen in other species, the application of crude collagenase for isolating canine islets resulted in highly variable islet yields, extensive islet fragmentation, and variable islet functionality. We compared the function of commercially available crude collagenases with that of Liberase™-CI purified enzyme blend for canine islet isolation. We also compared two manufacturing runs of Liberase-CI enzyme (lots 1 and 2) to demonstrate reproducibility of islet recovery and function. We report on the improved recovery and function of islets isolated using Liberase-CI enzyme. No difference in dog age, mean body weight, or pancreas weight were observed between the experimental groups. We observed a significantly higher postpurification recovery of islet equivalent number (IE) from pancreases processed using two lots of Liberase-CI enzyme (189 ± 20 × 103 IE, n = 4) and lot 2 (234 ± 39 × 103 IE, n = 7) than that obtained from pancreases processed with Sigma Type V (116.8 ± 27 × 103 IE, n = 5), Serva collagenase (49 ± 11.6 × 103 IE, n = 5, p < 0.05) or Boehringer–Mannheim (BM) Type P collagenase (85.4 ± 25 × 103 IE, n = 5, p < 0.05, ANOVA). No significant differences were observed in islet yield recovery from pancreases processed using the two production lots of Liberase-CI enzyme. Islet survival after 48 h in culture at 37°C was significantly higher from islets isolated using Liberase-CI enzyme (88 ± 3.7% survival) when compared to Sigma Type V (81.8 ± 3.3%), Serva (71.7 ± 2.8%), and BM Type P (77 ± 7.2%) (p < 0.05). Islet functional testing in vitro demonstrated islets isolated using crude collagenase had an increased insulin basal release and a reduced insulin stimulated response when compared with islets isolated using the two lots of Liberase-CI enzyme. The calculated stimulation index was 7.8 ± 1.7, 3.1 ± 0.6, and 4.8 ± 1.1 for Sigma Type V, Serva, and BM Type P isolated islets, respectively, compared to 15.7 ± 1.6 and 16.2 ± 1.9 for islets isolated with Liberase-CI enzyme production lots 1 and 2, respectively (p < 0.05). This evaluation demonstrates that a purified enzyme blend can significantly improve islet recovery and function. It also demonstrates the manufacturing reproducibility of Liberase-CI enzyme lots resulting in the isolation of canine islets with the same degree of efficacy. A blend of purified enzymes, specifically formulated for canine islet isolation, can consistently yield large numbers of islets that survive longer in culture and demonstrate an improved insulin response in vitro.

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