Hypoglycaemia is reduced with use of inhaled Technosphere® Insulin relative to insulin aspart in type 1 diabetes mellitus

AIM

To evaluate the effect of final HbA_1c levels on the incidences of hypoglycaemia in participants with type 1 diabetes treated with inhaled Technosphere^® Insulin or subcutaneous insulin aspart, reported in alignment with the International Hypoglycaemia Study Group recommendations.

METHODS

In the randomized, phase 3, multicentre AFFINITY-1 study, adults (N = 375) who had type 1 diabetes for ≥ 12 months and an HbA_1c level of 58-86 mmol/mol (7.5-10.0%) were randomized to receive basal insulin plus either inhaled Technosphere Insulin or subcutaneous insulin aspart. This was a post-hoc regression analysis on a subset (N = 279) of the randomized AFFINITY-1 cohort for whom baseline and end-of-treatment HbA_1c values were reported. Primary outcome measures were incidence and event rates for levels 1, 2 and 3 hypoglycaemia, respectively defined as blood glucose levels of ≤ 3.9 mmol/l, < 3.0 mmol/l or requiring external assistance for recovery.

RESULTS

Participants treated with Technosphere Insulin experienced statistically significantly fewer level 1 and 2 hypoglycaemic events and a lower incidence of level 3 hypoglycaemia than participants treated with insulin aspart. The lower rate of hypoglycaemia with Technosphere Insulin was observed across the range of end-of-treatment HbA_1c levels. Technosphere Insulin was associated with higher rates of hypoglycaemia 30-60 min after meals, but significantly lower rates 2-6 h after meals.

CONCLUSIONS

Participants using Technosphere Insulin experienced clinically non-inferior glycaemic control and lower hypoglycaemia rates across a range of HbA_1c levels compared with participants receiving insulin aspart. ClinicalTrials.gov: NCT01445951.

Is the current standard of care leading to cost-effective outcomes for patients with type 2 diabetes requiring insulin? A long-term health economic analysis for the UK

AIMS

The aim of the analysis was to investigate whether insulin intensification, based on the use of intensive insulin regimens as recommended by the current standard of care in routine clinical practice, would be cost-effective for patients with type 2 diabetes in the UK.

METHODS

Clinical data were derived from a retrospective analysis of 3185 patients with type 2 diabetes on basal insulin in The Health Improvement Network (THIN) general practice database. In total, 48% (614 patients) intensified insulin therapy, defined by adding bolus or premix insulin to a basal regimen, which was associated with a reduction in HbA1c and an increase in body mass index. Projections of clinical outcomes and costs (2011 GBP) over patients' lifetimes were made using a recently validated type 2 diabetes model.

RESULTS

Immediate insulin intensification was associated with improvements in life expectancy, quality-adjusted life expectancy and time to onset of complications versus no intensification or delaying intensification by 2, 4, 6, or 8 years. Direct costs were higher with the insulin intensification strategy (due to the acquisition costs of insulin). Incremental cost-effectiveness ratios for insulin intensification were GBP 32,560, GBP 35,187, GBP 40,006, GBP 48,187 and GBP 55,431 per QALY gained versus delaying intensification 2, 4, 6 and 8 years, and no intensification, respectively.

CONCLUSIONS

Although associated with improved clinical outcomes, insulin intensification as practiced in the UK has a relatively high cost per QALY and may not lead to cost-effective outcomes for patients with type 2 diabetes as currently defined by UK cost-effectiveness thresholds.

Interim analysis of the effects of exenatide treatment on A1C, weight and cardiovascular risk factors over 82 weeks in 314 overweight patients with type 2 diabetes

AIM

Exenatide, an incretin mimetic for the adjunct treatment of type 2 diabetes (DM2), reduced A1C and weight in 30-week placebo-controlled trials. This analysis examined the effects of exenatide on glycaemic control and weight over an 82-week period in patients with DM2 unable to achieve adequate glycaemic control with sulphonylurea (SU) and/or metformin (MET).

METHODS

This interim analysis is of 314 patients who received exenatide in the 30-week placebo-controlled trials and subsequently in 52 weeks of open-label uncontrolled extension studies for 82 weeks of exenatide in total. Patients continued their SU and/or MET regimens throughout.

RESULTS

Patients completed 82 weeks of exenatide treatment [n = 314, 63% M, age 56 +/- 10 years, weight 99 +/- 21 kg, body mass index 34 +/- 6 kg/m2, A1C 8.3 +/- 1.0% (mean +/- SD)]. Reduction in A1C from baseline to week 30 [-0.9 +/- 0.1% (mean +/- SE)] was sustained to week 82 (-1.1 +/- 0.1%), with 48% of patients achieving A1C < or = 7% at week 82. At week 30, exenatide reduced body weight (a secondary endpoint) from baseline (-2.1 +/- 0.2 kg), with progressive reduction at week 82 (-4.4 +/- 0.3 kg). Similar results were observed for the intent-to-treat population (n = 551), with reductions in A1C and weight at week 82 of -0.8 +/- 0.1% and -3.5 +/- 0.2 kg respectively. The 82-week completer cohort showed statistically significant improvement in some cardiovascular risk factors. The most frequent adverse events were generally mild-to-moderate nausea and hypoglycaemia.

CONCLUSION

In summary, 82 weeks of adjunctive exenatide treatment in patients with DM2 treated with SU and/or MET resulted in sustained reduction in A1C and progressive reduction in weight, as well as improvement in some cardiovascular risk factors.

Characterizing blood pressure control in individuals with Type 2 diabetes: the relationship between clinic and self-monitored blood pressure

AIMS

To determine the relationship between blood pressure (BP) measurement in the clinic and self-monitored blood pressure (SMBP); and to evaluate the accuracy of self-reported data in patients with Type 2 diabetes treated intensively for hypertension.

METHODS

Seventy subjects had baseline and 1-week follow-up clinic BP measured using an Omron 907 automated device. During a contemporaneous 14-day period these subjects measured their BP at least four times each day using an Omron IC semiautomatic portable monitor which, unknown to them, contained an onboard memory capable of storing BP with corresponding time and date.

RESULTS

There was no significant difference between mean clinic and mean self-monitored BP. Correlations between clinic BP and SMBP were r=0.61 (P<0.0001) for systolic BP and r=0.69 (P<0.0001) for diastolic BP. Clinic BP classified 56 subjects as uncontrolled hypertension (BP > or = 130/80 mmHg, adjusted for diabetes) and 14 subjects as controlled hypertension. Using World Health Organization-International Society of Hypertension criteria for SMBP (> or = 125/75 mmHg), 55 cases of clinic classified uncontrolled hypertension were confirmed, resulting in 98% sensitivity. Clinic and SMBP agreed in one case of controlled hypertension, resulting in 7% specificity. For all subjects, the median percent of values exceeding SMBP criteria for controlled hypertension was systolic 92% and diastolic 70%. Self-reporting precision averaged 89+/-10% (range 45-100%); under-reporting was 25+/-16% (ranging from 0 to 56%) and over-reporting was 12+/-15% (ranging from 0 to 46%). The overall logbook mean was not significantly different from the downloaded data from the Omron IC(R) monitors.

CONCLUSIONS

SMBP was able to identify 13 patients with uncontrolled hypertension who, by clinic BP measurement, had been classified as controlled.

Restored hypoglycemic counterregulation is stable in successful pancreas transplant recipients for up to 19 years after transplantation

BACKGROUND

Pancreas transplantation has been shown to fully restore glucagon response and partially restore epinephrine response to hypoglycemia during the first few years after transplantation in patients with type 1 diabetes. However, prior studies have not examined hypoglycemic counterregulation in any pancreas transplant recipient of more than 6 years' duration.

METHODS

To determine whether restoration of hypoglycemic counterregulation is maintained over a prolonged period after transplantation, we studied counterregulatory responses and symptom recognition in two groups of pancreas transplant recipients using a stepped hypoglycemic, hyperinsulinemic clamp. Group 1 consisted of 11 successful transplant recipients of 11 to 19 years' duration (mean+/-SE, 13.9+/-0.7 years). Group 2A consisted of seven successful pancreas transplant recipients of 5 to 11 years' duration (mean+/-SE, 8.7+/-0.9 years) who had been studied approximately 5 years earlier using the same stepped, hypoglycemic clamp technique.

RESULTS

Both groups had significant rises in plasma glucagon during the hypoglycemic clamp similar to that seen in short-term recipients and normal controls. Both groups also had significant increases in plasma epinephrine responses similar to that seen in short-term transplant recipients but less than that of normal control subjects. The mean symptom scores of group 1 were significantly less than those of the control group at glucose levels of 60 and 50 mg/dL but not at 40 mg/dL. The mean symptom scores of group 2A were not significantly different than that of control subjects.

CONCLUSION

These results indicate that the restoration of hypoglycemic counterregulation by pancreas transplantation remains stable in successful pancreas transplant recipients for up to 19 years after transplantation.

Comprehensive management of patients with type 2 diabetes: establishing priorities of care

Type 2 diabetes is a complex metabolic disorder characterized by elevated blood glucose levels and a marked increase in the risk of cardiovascular disease (CVD). The increased CVD risk is caused by a unique cluster of metabolic abnormalities, including dyslipidemia, hypertension, insulin resistance, and hyperglycemia. To reduce the risk of cardiovascular complications in patients with type 2 diabetes, comprehensive management of risk factors is essential. Aggressive treatment of dyslipidemia and hypertension is known to benefit patients with type 2 diabetes. In addition, intensive glycemic control and targeted treatment of insulin resistance can further reduce the enormous burden of CVD in this high-risk population. Increasing evidence suggests that insulin resistance is one of the earliest markers of risk for both CVD and diabetes, and it is known that insulin resistance alone can significantly increase the risk of CVD. Type 2 diabetes and insulin resistance are both associated with disordered lipid metabolism, manifest in elevated triglyceride levels, low levels of high-density lipoprotein cholesterol, and small, dense low-density lipoprotein cholesterol particles. Patients with type 2 diabetes and insulin resistance have an increased risk of hypertension, which further contributes to their CVD risk. Each of these factors can also contribute to the risk of microvascular disease. To ensure that patients with type 2 diabetes receive comprehensive, high-quality care, specific standards have been developed. These standards can help providers establish clear treatment targets, identify specific priorities of care, and use therapies of known efficacy to reduce the risk of complications. This review summarizes the current standards of care for patients with type 2 diabetes, with an emphasis on treatments that reduce the cardiovascular risk factors. Using a case study approach, it reviews the essential components of diabetes care and proposes a rational approach to these complex cases--an approach that should result in consistent, high-quality care.

Prevention of diabetes for up to 13 years by autoislet transplantation after pancreatectomy for chronic pancreatitis

Patients with chronic pancreatitis who undergo total pancreas resection inevitably become diabetic unless their islets are autotransplanted to prevent diabetes. We studied patients who underwent this procedure to assess its long-term efficacy in providing stable glucose regulation. Six patients were followed for up to 13 (6.2 +/- 1.7) years after intrahepatic islet autotransplantation. From 290,000 to 678,000 islets were transplanted and no patients received drugs to control glucose levels postoperatively. Islet function was assessed by measurements of fasting plasma glucose (FPG), intravenous glucose disappearance rate (KG), HbA1c, insulin responses to intravenous glucose and to arginine, and insulin secretory reserve. Patients were studied two to four times each to obtain longitudinal data. Five of six patients remained free of insulin treatment and maintained FPG <126 mg/dl and HbA1c levels <6.5%. As a group, they maintained stable insulin secretory reserve, but insulin responses to glucose tended to decrease over time in three patients. KG values correlated significantly with the number of islets originally transplanted. These data indicate that intrahepatic autoislet transplantation can successfully maintain stable beta-cell function and normal levels of blood glucose and HbA1c for up to 13 years after total pancreatectomy as treatment for chronic painful pancreatitis. This usually overlooked procedure of intrahepatic islet transplantation designed to prevent diabetes in patients undergoing pancreatectomy for chronic pancreatitis should be considered more often.

Successful islet autotransplantation in humans: functional insulin secretory reserve as an estimate of surviving islet cell mass

Islet autotransplantation for treatment of chronic painful pancreatitis in nondiabetic patients reliably establishes normoglycemia and phasic insulin secretion and can achieve prolonged insulin independence. Whether functional transplanted beta-cell reserve is normal after intrahepatic islet transplantation is not known, nor is it known whether conventional measures of insulin secretion accurately reflect the functional beta-cell mass. To determine insulin secretory reserve after islet transplant, we performed studies of glucose potentiation of arginine-induced insulin secretion (GPAIS) in eight recipients of intrahepatic islet autotransplants. All eight subjects (and matched, healthy controls) were studied cross-sectionally 49 +/- 12 months posttransplant, and four subjects were studied pre- and posttransplant. Subjects had received a mean +/- SE of 479,000 +/- 79,000 islets, and all were insulin independent and normoglycemic at the time of study. Acute insulin responses to arginine, glucose, and GPAIS were significantly reduced after islet transplantation in both study groups. Importantly, the magnitudes of these three responses were highly correlated to the mass of islets transplanted (response to glucose: r = 0.84, P < 0.01; response to arginine: r = 0.69, P < 0.05; response to GPAIS = 0.81, P < 0.01). Data from hemipancreatectomized and normal control subjects generally agreed with the regression lines. These findings demonstrate that despite normoglycemia and insulin independence, recipients of intrahepatic islet transplantation have significantly reduced functional beta-secretory reserve and that after islet transplantation, functional beta-cell mass can be estimated by measurements of glucose and arginine-induced insulin responses. Thus, these measurements can be used to estimate the mass and functional capacity of islets surviving intrahepatic transplantation in humans.

Simultaneous pancreas-kidney transplantation from live donors

OBJECTIVE

In this first report of a clinical series of simultaneous pancreas-kidney transplants (SPKs) from live donors, the authors assess donor and recipient outcome as well as the spectrum of surgical and metabolic complications.

SUMMARY BACKGROUND DATA

The rationale for live (vs. cadaveric) donation includes an immunologic advantage (better matching, decreased drugs, and fewer rejection episodes) and elimination of waiting time. Only sequential kidney and pancreas or pancreas transplants alone from live donors had been done until the authors' current series.

METHODS

Between March 15, 1994, and March 15, 1997, the authors performed 20 SPKs from live donors (6 human leukocyte antigen-identical siblings, 14 mismatched relatives [5 parents, 7 siblings, 1 daughter, 1 aunt]). Of the 20 donors, 13 were women, and 7 were men; median age was 43 years (range, 30-58 years). All donors underwent standardized metabolic workup, including oral glucose tolerance tests, determination of hemoglobin A1 c levels, and tests to study insulin secretion and functional insulin secretory reserve. Of the 20 recipients, 12 were women, and 8 were men; median age was 34 years (range, 14-50 years). Management of exocrine pancreatic secretions was with bladder drainage in 17 and duct injection in 3 recipients. Median follow-up was 9 months (range, 1-36 months).

RESULTS

Currently, all 20 kidney grafts are functioning. Of the 20 pancreas grafts, 15 are functioning, 3 thrombosed, but 2 of those patients underwent immediate retransplantation from a cadaveric donor, and their grafts currently are functioning. Recipient complications included three anastomotic leaks and three intra-abdominal abscesses. Donor complications included four splenectomies, two peripancreatic fluid collections, one pseudocyst, and one intra-abdominal abscess; two donors underwent reoperation. Three donors had impaired glucose metabolism postdonation. Using tacrolimus and mycophenolate mofetil for mainstay immunosuppression, only 8 of 20 recipients experienced > or =1 rejection episode; only 1 pancreas graft was lost to rejection. Donor and recipient mortality was 0%.

CONCLUSION

Simultaneous pancreas-kidney transplants from live donors can be done with no mortality and good graft outcome. With stringent donor criteria, this approach could become another surgical alternative for endocrine replacement therapy in selected patients with uremic type I diabetes.

Pancreas and islet transplantation. Challenges for the twenty-first century

This article reviews both pancreas and islet transplantation in detail. The history of each procedure, the effects of these therapies on glucose metabolism, glucose counterregulation, and islet cell secretory function, as well as the challenges that result from each procedure are considered.

Pancreas transplantation restores epinephrine response and symptom recognition during hypoglycemia in patients with long-standing type I diabetes and autonomic neuropathy

Impaired epinephrine secretion and symptom unawareness are characteristic of severe hypoglycemia in individuals with long-standing type I diabetes. Recently, the avoidance of clinical hypoglycemia has been reported to improve epinephrine and symptom responses to hypoglycemia in type I patients. However, the extent to which these defects can be restored in individuals with long-standing type I diabetes and autonomic neuropathy has not been assessed, nor has it been determined whether pancreas transplantation, which not only obviates hypoglycemia but also prevents hyperglycemia, results in the complete recovery of either epinephrine response or symptom awareness during insulin-induced hypoglycemia. We performed stepped hypoglycemic clamp studies in successful pancreas transplantation recipients to assess epinephrine and other counterregulatory hormone responses during hypoglycemia and to determine the degree to which hypoglycemic symptom recognition could be restored. Thirteen pancreas transplant recipients and matched control subjects were studied utilizing stepped hypoglycemic clamp protocol to achieve target glucose levels of 3.9, 3.3, 2.8, and 2.2 mmol/l (70, 60, 50, and 40 mg/dl, respectively). Plasma epinephrine response was significantly greater in healthy control subjects and pancreas transplant patients compared with type I subjects at the glucose plateaus of 3.9, 3.3, and 2.8 mmol/l. However, epinephrine response in pancreas transplant recipients was significantly less than that seen in either healthy control subjects or nondiabetic kidney transplant recipients at each of these glucose plateaus. The magnitude of the epinephrine response in pancreas transplant type I patients did not correlate with either the duration of diabetes, the duration of transplantation, or the measures of autonomic nerve function. Hypoglycemic symptom recognition was significantly greater in pancreas transplant subjects than type I patients and did not differ between pancreas transplant and control groups. No improvement in norepinephrine response was observed after pancreas transplantation, while glucagon responses to hypoglycemia were normalized in pancreas transplant patients. In conclusion, these studies uniquely demonstrate that successful pancreas transplantation improves epinephrine response and normalizes hypoglycemia symptom recognition in patients with long-standing diabetes and established autonomic neuropathy. No correlation was observed between the severity of autonomic neuropathy or the duration of diabetes and the recovery of either the epinephrine or symptom responses to hypoglycemia.

The defective glucagon response from transplanted intrahepatic pancreatic islets during hypoglycemia is transplantation site-determined

The optimal site for pancreatic islet cell transplantation is presently unclear, although the liver has been the most commonly used. However, glucagon secretion from islets that have been autotransplanted in liver has been reported to be unresponsive to hypoglycemia yet responsive to arginine. To determine whether this selective glucagon secretory defect is related to the intrahepatic site of islet implantation or to the process of transplantation per se, we studied counterregulatory responses to hypoglycemia in dogs with pancreatic islet autotransplantation in the hepatic parenchyma (the intrahepatic [IH] group, n = 9) or the peritoneal cavity (the intraperitoneal [IP] group, n = 9), following total pancreatectomy, and compared them with the responses in normal controls (n = 10). Dogs were subjected to a hypoglycemic hyperinsulinemic (5 mU x kg-1 x min-1) clamp for 90 min under general anesthesia. Arterial glucose concentrations were clamped at 2.7 mmol/l for the final 45 min of the clamp. Immediately following the clamp, glucagon responses to IV arginine (5 g) were also assessed. During hypoglycemia, glucagon responses in the IH group (maximal incremental glucagon = 33 +/- 21 ng/l; glucagon area under curve [AUC] = 713 +/- 1,022 ng x l-1 x min-1) were significantly lower than either the IP (maximal incremental glucagon = 92 +/- 32 ng/l; glucagon AUC = 4,090 +/- 1,600 ng x l-1 x min-1) or control (maximal incremental glucagon = 154 +/- 71 ng/l; glucagon AUC = 6,943 +/- 2,842 ng x l-1 x min-1) group (IH vs. IP group, P < 0.05; control vs. IH group, P < 0.01). Glucagon responses in the IP group did not differ significantly from the control group. Epinephrine responses to hypoglycemia were similar in all groups, whereas neither of the transplanted groups (IH and IP) had pancreatic polypeptide responses. There was a prompt rise in plasma glucagon after intravenous arginine in all groups. These data indicate that glucagon unresponsiveness to hypoglycemia is specific to intrahepatically transplanted islets, rendering the liver a disadvantageous site for optimal alpha-cell function.

Defective glucagon secretion during sustained hypoglycemia following successful islet allo- and autotransplantation in humans

Defective glucagon secretion during hypoglycemia is characteristic of long-standing type I diabetes. To determine whether this defect can be corrected by successful intrahepatic islet transplantation, we performed studies of hypoglycemia in four nondiabetic patients with chronic pancreatitis who had undergone total pancreatectomy and successful intrahepatic islet autotransplantation, in two type I diabetic recipients of successful intrahepatic islet allotransplantation, and in matched control subjects. We examined 1) whether intrahepatic islet autotransplantation provides glucagon secretion during prolonged periods of hypoglycemia and 2) whether intrahepatic islet allotransplantation in type I diabetic patients and consequent long-term normoglycemia reestablishes native alpha-cell responses to hypoglycemia. Glucagon secretion was assessed during 3-h hypoglycemic hyperinsulinemic clamp studies. The islet autograft recipients were studied 63 +/- 19 months posttransplant, and all were insulin-independent and normoglycemic (HbA(1c), 5.8 +/- 0.2%). Neither allograft recipient required exogenous insulin and maintained HbA(1c) levels of 5.7 and 6.4% 30 and 34 months posttransplant, respectively. All recipients were normoglycemic (fasting glucose: autograft recipients, 5.6 +/- 0.1 mmol/l; allograft recipient #1, 6.3 mmol/l; allograft recipient #2, 5.8 mmol/l) at the time of study. During hypoglycemia, no increase in glucagon secretion was observed in either the auto- or allotransplant recipients, whereas healthy control subjects and recipients of kidney transplantation had significant increases in glucagon. In contrast, both allo- and autograft recipients had glucagon responses to intravenous arginine. These data uniquely demonstrate that: 1) intrahepatic islet transplant grafts secrete glucagon in response to arginine, but fail to secrete glucagon in response to sustained hypoglycemia; and 2) the restoration of sustained normoglycemia for over 2 years in type I diabetic patients may not reestablish glucagon responses from the native pancreas during hypoglycemia. Transplantation sites other than the liver may be required to achieve normal glucagon secretion from the transplanted islets.

Metabolic characterization of long-term successful pancreas transplants in type I diabetes

BACKGROUND

The encouraging results of the Diabetes Control and Complications Trial emphasize the need for improved methods of glycemic control to prevent the potentially devastating complications of Type I diabetes mellitus. However, current conventional approaches have failed to consistently achieve normal HbAlc levels and increase the risk of hypoglycemia. Pancreas transplantation is a consistently reliable method of achieving postoperative normal glucose levels, but no extensive assessment has been made of the long-term stability of its metabolic benefits.

METHODS

To ascertain long-term stability of metabolic function of pancreas transplants in Type I diabetic patients, we studied fasting glucose levels, glucose disposal after intravenous glucose challenge, HbAlc levels, and pancreatic islet beta and alpha cell responsiveness in a series of 96 successfully transplanted recipients. Patients were studied cross-sectionally and, when possible, longitudinally for up to five years post-transplantation. Special emphasis was given to the longitudinal analysis to determine whether initial metabolic benefits maintain stability or undergo deterioration during the first five postoperative years.

RESULTS

Pancreas transplantation was accompanied by normal or nearly normal fasting plasma glucose levels, intravenous glucose disappearance rates, and HbAlc levels. Beta cell function assessed by acute insulin responses and acute C-peptide responses to intravenous glucose injections revealed no deterioration in the magnitude of these responses. Analysis of acute insulin and C-peptide responses to intravenous arginine provided similar results. Alpha cell function, assessed by measuring acute glucagon responses to intravenous arginine, were significantly (p > .001) greater than preoperative responses and remained stable over the ensuing five-year period. In grafts that maintained function, none of these metabolic measures showed deterioration during the five-year postoperative period.

CONCLUSIONS

Successful pancreas transplantation provides pancreatic islet function that results in normal or near normal glycemic control for up to five years postoperatively in Type I diabetic recipients receiving no exogenous insulin or oral hypoglycemic agent therapy.

Pancreas and islet transplantation in humans

Pancreas transplantation is the only treatment presently available for patients with Type 1 diabetes that establishes both insulin independence and sustained normoglycaemia. This normoglycaemia is associated with potential beneficial effects on the secondary microvascular complications of diabetes. Pancreas transplantation also improves the quality of life for diabetic patients. Islet transplantation has had only limited success to date, but when successful restores regulated insulin secretion and establishes insulin independence. However, despite the benefits of both pancreas and islet transplant for carbohydrate metabolism and diabetic complications, neither is considered standard therapy for patients with IDDM. Both types of transplantation require life-long immunosuppressive therapy. Pancreas transplant is further limited by the significant risks of the surgical procedure. In order for either pancreas or islet transplantation to achieve the clinical acceptability of other forms of transplantation, clear advantages over exogenous insulin therapy must be demonstrated.

Islet Autotransplantation after total pancreatectomy in a child

Islet autotransplantation can prevent surgically induced diabetes after total pancreatectomy in adults; however, the efficacy of this procedure has not been established in children. The authors report the case of a 12-year-old boy who underwent total pancreatectomy and islet autotransplantation for intractable pain caused by idiopathic chronic pancreatitis. Islets were prepared from the excised pancreas by collagenase digestion and mechanical dispersion. The resultant preparation, containing 109,500 islets, was injected into the recipient's liver via the portal vein. No complication from the pancreatectomy or transplant occurred. Postoperatively, the patient had complete relief of abdominal pain. He remained insulin-independent, with normal fasting blood glucose and hemoglobin A1c levels, for 21/2 years. Preoperatively, the acute insulin response and the rate of glucose disappearance (Kg) were 213 microU/mL and 2.14% (respectively) after intravenous administration of 20 g of glucose. Although lower than pretransplantation values, both insulin response and Kg remained normal at 4 months (88 microU/mL; Kg, 1.01%); however, these decreased further, to below normal, by 2 years posttransplantation (10 microU/mL; Kg, 0.67%). Two-and-a-half years after transplantation, fasting hyperglycemia (> 200 mg/dL) was evident, and the patient was begun on exogenous insulin. Five years posttransplantation he remains insulin-dependent with a fasting serum C-peptide level of 0.20 ng/mL, which increased to 0.35 ng/mL in response to intravenous arginine, indicating sustained islet function. During the documented decreases in insulin secretion and Kg posttransplantation, the patient's body weight increased by 65% (from 34 to 56 kg) as a result of normal growth; the number of transplanted islets relative to body mass decreased accordingly, from 3,200 to 1,950 islets per kilogram of body weight. In this case, the number of islets transplanted likely could not meet the increased insulin demands of the larger body mass. Thus, exogenous insulin supplementation was needed to prevent hyperglycemia. In conclusion, insulin independence was initially established in a child by islet autotransplantation after total pancreatectomy. The failure of the islets to maintain normoglycemia long-term suggests that a sufficient number must be transplanted (to meet the demands of normal growth and development) for sustained insulin independence.

Somatostatin coordinately regulates glucagon gene expression and exocytosis in HIT-T15 cells

Somatostatin (SRIF) regulates secretion from several endocrine cell types. SRIF inhibits both insulin and glucagon secretion and reduces insulin gene expression. However, whether SRIF inhibition of glucagon secretion from the pancreatic alpha cell is mediated via pertussis toxin-sensitive G-proteins is not presently known, nor has it been determined whether SRIF can regulate glucagon gene expression. Consequently, we performed studies in the transformed islet cell line HIT-T15 to determine whether the inhibitory effect of SRIF on glucagon exocytosis is preserved in this cell line, whether this effect is mediated through a pertussis toxin-sensitive mechanism, and whether SRIF has an inhibitory effect on glucagon gene expression. Confocal microscopy with immunostaining revealed that 15-25% of HIT-T15 cells contained glucagon. In static incubations forskolin (FSK, 1 microM) increased glucagon secretion 3.6 +/- 0.9-fold (P < 0.01) and mixed amino acids (15 mM) increased glucagon secretion 2.8 +/- 0.4-fold (P < 0.01). Addition of SRIF significantly inhibited both forskolin- and amino acid-stimulated secretion. Maximal inhibition of both FSK- and amino acid-stimulated secretion occurred at SRIF concentrations > or = 10(-8) M and these inhibitory effects were completely prevented by pertussis toxin pretreatment. In addition to inhibiting glucagon secretion, SRIF significantly reduced both basal and FSK-stimulated glucagon mRNA levels and this reduction in glucagon mRNA was completely prevented by the addition of cyclic AMP analogue. Glucagon gene promoter activity, as assessed by transient transfection experiments, was stimulated 2.1 +/- 0.25-fold by forskolin (P < 0.01). This effect was significantly inhibited by SRIF (71 +/- 4% reduction from FSK alone, P < 0.04) suggesting that SRIF inhibition of the glucagon promoter may, at least in part, account for the observed decrease in glucagon mRNA levels. These studies uniquely demonstrate that glucagon secretion from the HIT-T15 cell line is inhibited by SRIF through a pertussis toxin-sensitive mechanism and that SRIF also inhibits glucagon gene expression in part by reducing glucagon promoter activity. These findings indicate that SRIF can coordinately regulate glucagon delivery by the alpha cell both at the level of gene expression and hormone exocytosis.

Autologous islet transplantation to prevent diabetes after pancreatic resection

BACKGROUND

Extensive pancreatic resection for small-duct chronic pancreatitis is often required for pain relief, but the risk of diabetes is a major deterrent.

OBJECTIVE

Incidence of pain relief, prevention of diabetes, and identification of factors predictive of success were the goals in this series of 48 patients who underwent pancreatectomy and islet autotransplantation for chronic pancreatitis.

PATIENTS AND METHODS

Of the 48 patients, 43 underwent total or near-total (> 95%) pancreatectomy and 5 underwent partial pancreatectomy. The resected pancreas was dispersed by either old (n = 26) or new (n = 22) methods of collagenase digestion. Islets were injected into the portal vein of 46 of the 48 patients and under the kidney capsule in the remaining 2. Postoperative morbidity, mortality, pain relief, and need for exogenous insulin were determined, and actuarial probability of postoperative insulin independence was calculated based on several variables.

RESULTS

One perioperative death occurred. Surgical complications occurred in 12 of the 48 patients (25%): of these, 3 had a total (n = 27); 8, a near-total (n = 16); and 1, a partial pancreatectomy (p = 0.02). Most of the 48 patients had a transient increase in portal venous pressure after islet infusion, but no serious sequelae developed. More than 80% of patients experienced significant pain relief after pancreatectomy. Of the 39 patients who underwent total or near-total pancreatectomy, 20 (51%) were initially insulin independent. Between 2 and 10 years after transplantation, 34% were insulin independent, with no grafts failing after 2 years. The main predictor of insulin independence was the number of islets transplanted (of 14 patients who received > 300,000 islets, 74% were insulin independent at > 2 years after transplantation). In turn, the number of islets recovered correlated with the degree of fibrosis (r = -0.52, p = 0.006) and the dispersion method (p = 0.005).

CONCLUSION

Pancreatectomy can relieve intractable pain caused by chronic pancreatitis. Islet autotransplantation is safe and can prevent long-term diabetes in more than 33% of patients and should be an adjunct to any pancreatic resection. A given patient's probability of success can be predicted by the morphologic features of the pancreas.

[Function of pancreas transplants in increased metabolic stress]

Patients undergoing successful pancreas transplantation have normal glucose levels in the fasting and fed states and normal levels of hemoglobin A1c without use of exogenous inulin or any other medications for diabetes. In some of these patients, these measures have remained stable for more than 10 years. Additionally pancreas transplant recipients recover from short-term hypoglycemia produced by an intravenous pulse of insulin. However, metabolic success has been determined by relatively routine, unsophisticated tests such as oral and intravenous glucose tolerance tests or stimulation with intravenous arginine. These tests may not provide measures of the functional reserve of the pancreas, which is called on during periods of maximal stress. Consequently, we designed studies to ascertain beta and alpha cell performance in recipients of whole pancreas transplants and recipients of a segment of a living related donor. All recipients were recruited from the University of Minnesota Transplant Registry, Minneapolis, Minnesota. Successfully transplanted recipients were subjected to prolonged hyperglycemia to assess insulin secretory reserve using the method of glucose potentiation of arginine induced insulin secretion and to prolonged hypoglycemia to assess glucagon responsiveness and hepatic glucose production using the technique of the hyperinsulinemic hypoglycemic clamp. Our studies show that pancreas transplant recipients have markedly diminished insulin secretory reserve, a defect not evident with conventional tests of beta-cell function. No difference was found between the whole graft and segmental graft recipients. Pancreas transplantation restores the defective glucagon secretory response and enhances hepatic glucose production during prolonged hypoglycemia in subjects with type I diabetes. We conclude that pancreas transplantation does not completely restore beta-cell secretory reserve. This defect might be probably caused in part by cyclosporine and by the procedure involved in transplanting a cadaveric pancreas. Pancreas transplantation normalizes hypoglycemia-induced glucagon secretion and hepatic glucose production, thereby allowing for normalization of glucose recovery from hypoglycemia.

Preserved insulin secretion and insulin independence in recipients of islet autografts

BACKGROUND

Transplantation of pancreatic islets, rather than whole pancreas, has been introduced as a treatment for diabetes mellitus. We studied five patients ranging in age from 12 to 37 years who had severe chronic pancreatitis for which they underwent total pancreatectomy followed by isolation and hepatic transplantation of their own islets.

METHODS

All patients had remained insulin-independent for 1 to 7 1/2 years after transplantation. The numbers of islets transplanted ranged from 110,000 to 412,000. Islet function was assessed by measuring the plasma insulin responses to intravenous glucose and arginine and the plasma glucagon responses to hypoglycemia and arginine. In one patient, islet function was studied during catheterization of the hepatic vein, portal vein, and splenic artery and by analysis of a liver-biopsy specimen.

RESULTS

After transplantation, the mean (+/- SD) fasting plasma glucose concentration was 122 +/- 47 mg per deciliter (6.8 +/- 2.6 mmol per liter) and the hemoglobin A1c concentration was 6.0 +/- 0.8 percent in the five patients. The values were most abnormal--214 mg per deciliter (11.9 mmol per liter) and 7.3 percent, respectively--in the patient who received only 110,000 islets. The acute plasma insulin responses to glucose and to arginine in the five patients were 23 +/- 13 and 26 +/- 10 microU per milliliter (168 +/- 94 and 184 +/- 70 pmol per liter), respectively, as compared with 58 +/- 6 and 37 +/- 8 microU per milliliter (416 +/- 44 and 267 +/- 61 pmol per liter) in the normal subjects. The peak plasma glucagon responses to insulin and arginine were 21 +/- 4 and 65 +/- 36 pg per milliliter, respectively, as compared with 125 +/- 28 and 156 +/- 99 pg per milliliter in the normal subjects. All five patients had plasma epinephrine but not pancreatic polypeptide responses to hypoglycemia. The results of the hepatic-vein catheterization in one patient indicated that the transplanted islets released insulin and glucagon in response to arginine. Immunoperoxidase staining of this patient's liver-biopsy specimen showed that the islets contained insulin, glucagon, and somatostatin but not pancreatic polypeptide.

CONCLUSIONS

Intrahepatic transplantation of as few as 265,000 islets can result in the release of insulin and glucagon at appropriate times and in prolonged periods of insulin independence.

Long-term metabolic function of pancreas transplants and influence of rejection episodes

Pancreas grafts, when not rejected, can sustain an insulin-independent state in type I diabetic recipients for indefinite periods. To what extent the metabolic control achieved approaches that of normal individuals, the relationships between graft endocrine and exocrine function, the effect of reversible rejection episodes on subsequent graft function, and the correlation between the results of serial tests of graft function were determined by studies at 1 month, 1 year, and 2 years in a cohort of 39 recipients (29 females, 10 males; mean age (+/- SD), 33 +/- 5 years; mean duration of diabetes, 22 +/- 6 years) of bladder-drained pancreas transplants performed between November 1984 and December 1988. Fifteen patients received a pancreas transplant alone, 8 a pancreas after a kidney, and 16 a simultaneous pancreas/kidney transplant. Graft endocrine function was tested by a 24-hr metabolic profile of blood glucose levels before meals, at 1 and 2 hr after meals, and during the night (14 values in all), by intravenous and oral blood glucose tolerance tests, and by glycosylated hemoglobin levels (HA1 and HA1c). Graft exocrine function was assessed by urine amylase activity (U/hr). The results of the tests in the recipients were subjected to paired comparisons between timepoints and at each timepoint to the results of the same tests in 55 normal nondiabetic control individuals. The means of the mean 24-hr profile glucose (mg/dl) values were significantly lower (P less than 0.05) at 1 and 2 years posttransplant (116 +/- 27 and 115 +/- 15, respectively) than at 1 month (128 +/- 31) in the recipients, but the mean of the mean values in the normal controls (100 +/- 7) was even lower (P less than 0.05). Mean values of individual timepoints during the profile were significantly lower for 6 of the 14 values in the controls than in the recipients. The mean IVGTT K value of the normal controls (-1.9 +/- 0.4%) was significantly lower than the 1-month and 2-year values of the recipients (-1.5 +/- 0.5% and -1.3 +/- 0.6%, respectively), but the comparison with the 1-year value (-1.6 +/- 0.6%) was not significant. The mean glucose levels at zero minutes and between 120 and 300 min of the OGTTs were significantly lower at both 1 and 2 years than at 1 month in the recipients, and the values in the control group were also significantly lower than in the recipients at 1 month but not at 1 and 2 years.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of hemipancreatectomy on insulin secretion and glucose tolerance in healthy humans

Pancreatic tissue obtained by hemipancreatectomy from healthy living related donors has been transplanted into recipients with Type I diabetes mellitus. To determine the metabolic consequences of this procedure for the donors, we carried out oral glucose-tolerance testing and 24-hour monitoring of serum glucose levels and urinary C-peptide excretion as a measure of insulin secretion in 28 donors, both before and one year after hemipancreatectomy. The mean fasting serum glucose level was significantly higher one year after the procedure (mean +/- SD, 5.4 +/- 0.9 vs. 4.9 +/- 0.5 mmol per liter; P less than 0.003), as was the serum glucose value two hours after the administration of glucose (8.7 +/- 2.9 vs. 6.5 +/- 1.0 mmol per liter; P less than 0.001). The fasting serum insulin level was significantly lower one year after hemipancreatectomy (33.0 +/- 21.6 vs. 38.4 +/- 21.6 pmol per liter; P less than 0.05), as was the area under the insulin curves during the oral glucose-tolerance test (52,554 +/- 22,320 vs. 76,230 +/- 33,354 pmol per liter per minute; P less than 0.04). The mean 24-hour serum glucose-profile value was higher at one year, and the 24-hour urinary C-peptide excretion was lower in the 17 donors who underwent these studies. Seven of the 28 donors had abnormal glucose tolerance one year after hemipancreatectomy; however, insulin secretion in these 7 donors was indistinguishable from that in the 21 donors who had normal glucose tolerance. All 28 donors had fasting serum glucose concentrations lower than 7.8 mmol per liter, and their mean 24-hour plasma glucose levels remained within the normal range. We conclude that in healthy donors hemipancreatectomy results in a deterioration of insulin secretion and glucose tolerance, as measured one year later. Further study is required to ascertain whether the development of clinical diabetes mellitus is a risk inherent in hemipancreatectomy.

Metabolic effect of hemipancreatectomy in donors. Preoperative prediction of postoperative oral glucose tolerance

Between November 1977 and January 1987, 55 transplantations of pancreas segments from living donors related to their recipients were performed at the University of Minnesota. A preliminary analysis of metabolic test results in donors tested 1 yr after hemipancreatectomy showed an increase in mean glucose and a decrease in mean insulin values during oral glucose tolerance tests (OGTTs) in 18 donors, a 14% increase in the mean of the mean glucose levels during 24-h metabolic profiles in 12 donors, and a decrease of 45% in the mean 24-h urinary C-peptide excretion in 21 donors. Including the studies performed postdonation, 11 of 31 (35%) donors developed an abnormal OGTT result. In a retrospective analysis, preoperative results of intravenous glucose tolerance tests (IVGTTs) and cortisone-stimulated OGTTs were found to be statistically significant predictors of an abnormal OGTT after hemipancreatectomy. The mean of the 5- to 50-min IVGTT insulin values was the best predictive test. With the cutoff value set at 62 microU/ml, this test result had a sensitivity of 100%, a specificity of 83%, and a positive predictive value of 75% for identifying donors who developed an abnormal OGTT. The sum of the 5- and 10-min IVGTT insulin (cutoff 140 microU/ml) had a sensitivity of 100%, a specificity of 67%, and a predictive value of only 60%, whereas the delta-insulin had values of 86, 71, and 60%, respectively. Both the IVGTT mean insulin and the sum of the 5-min and 10-min insulin test results were 100% predictive of an abnormal test (0% risk), but the IVGTT mean insulin excluded the lowest proportion of otherwise suitable donors (a low "false-alarm" rate). The IVGTT mean insulin can be used to identify or exclude potential donors who would develop an abnormal OGTT result should hemipancreatectomy be performed.

Pancreas transplantation in nonuremic, type I diabetic recipients

Between July 1978 and January 1988, 111 of 210 pancreas transplants were in nonuremic, nonkidney (NUNK) recipients in whom complications of diabetes were judged more serious than the potential side effects of antirejection therapy. In all NUNK cases, the 1-year patient survival rate (PSR) and graft survival rate (GSR) were 90% and 39%. Since November 1984, 1-year PSR and GSR for 62 NUNK recipients of pancreas transplants alone (PTA) were 93% and 48%, compared to 89% and 37% for 28 pancreas transplants after (PAK) and 89% and 73% for 20 simultaneous (SPK) with a kidney transplant. The 1-year GSR for 1984-88 technically successful (TS) PTA cases (n = 47) was 63%, versus 75% for PAK (n = 13) and 86% for SPK (n = 17) cases. The 1-year GSRs, by technique and source for 1984-88 PTA cases, were 58% for bladder-drained cadaver (n = 30), 51% for enteric-drained related (n = 32), and 29% for enteric-drained cadaver (n = 17) donor transplants, and 75% (n = 24), 77% (n = 16), and 38% (n = 13) for the corresponding TS cases. Of NUNK recipients, 35 have had grafts function for more than 1 year and all but 3 were treated with cyclosporine (CsA). In the CsA-treated recipients, serum creatinine increased and creatinine clearances decreased by a magnitude of 40% during the first 6 months but thereafter remained stable in all but 2 patients. In the patients with functioning grafts studied at 1 year, retinopathy remained stable in 59% and progressed in 41% of the eyes (n = 39). Motor nerve conduction velocities were significantly increased and muscle action potentials remained stable in 24 patients with functioning grafts studied at 1 year, while in 14 patients in whom transplants failed there was a significant decrease in evoked muscle action potentials. A sustained euglycemic, insulin-independent state can be established in nonuremic, nonkidney diabetic recipients of pancreas transplants alone, with a beneficial effect on neuropathy, lack of an immediate benefit on advanced retinopathy, and an effect on nephropathy compounded by the influence of CsA on renal function.

One institution's experience with pancreas transplantation

The University of Minnesota has the largest experience with pancreas transplantation of any institution, with 130 cases since 1966, including 116 in 98 patients between July 1978 and June 1985. Currently, 30 patients are insulin-independent, 19 for greater than one year, the longest for seven years. One-year patient and graft survival rates overall are 87% and 30%, respectively. Of 98 recipients, 49 had had previous kidney transplants, while 49 had not, and currently most of the pancreas recipients do not have uremia and have not had a kidney transplant but have early complications of diabetes. A total of 44 of the grafts were procured from related and 72 from cadaver donors. Although 32 of the 116 grafts (28%) failed for technical reasons, the most common cause of graft failure has been rejection. Various immunosuppressive regimens have been used in attempts to reduce the rejection rate, and one combination, low-dose cyclosporine-azathioprine-prednisone (triple therapy), has been particularly effective, with a one-year functional survival rate of 73% in recipients of technically successful grafts from human leukocyte antigen-mismatched cadaver or related donors (N = 20). The pancreas graft survival rates have improved gradually (43% for 1984 to 1985, N = 30; versus 27% for 1978 to 1983, N = 86) for transplants from both related and cadaver donors. Metabolic studies from most recipients with functioning grafts (insulin-independent) show normal or nearly normal results. Preliminary observations on secondary complications suggest a more favorable course in recipients whose grafts have functioned long term than in those whose grafts failed early.

Pancreas transplantation--registry report and a commentary

From December 1966 through December 1984, there were 561 pancreas transplants reported to the American College of Surgeons/National Institutes of Health Organ Transplant Registry, including 60 from 1966 through June 1977, 206 from July 1977 through December 1982 and 295 from January 1983 through December 1984. One-year graft function-survival rates (insulin-independent) in each of the three periods were 3%, 20% and 40%, and the corresponding patient survival rates were 40%, 72% and 77%. Currently 140 patients have functioning grafts, 76 for more than one year. Of the transplants since July 1977, one-year graft survival rates according to technique are 41% for enteric drainage (N = 155), 30% for polymer injection (N = 260) and 29% for urinary drainage (N = 47). Pancreas graft survival rates at one year according to whether or not the recipients have had a kidney transplant were 35% for recipients of simultaneous grafts (N = 281), 28% in recipients of a pancreas after a kidney (N = 112) and 26% in recipients of a pancreas only who did not have uremia (N = 106); corresponding patient survival rates were 69%, 83% and 83%. Overall, one-year pancreas graft survival rates according to whether the patients did or did not have end-stage diabetic nephropathy were 33% versus 25% and the corresponding patient survival rates were 73% versus 84% (P < .01). Patient survival rates were significantly higher in those without than in those with end-stage diabetic nephropathy. An analysis of technically successful grafts according to principal immunosuppressant showed one-year function rates of 46% in 258 cyclosporine-treated recipients and 26% in 143 azathioprine-treated recipients. Pancreas graft survival rates have progressively improved and the procedure has become safer with advances in surgical technique and immunosuppression. Pancreas transplantation is currently applicable to patients with diabetes mellitus whose complications are, or predictably will be, more serious than the possible side effects of long-term immunosuppression.