Modeling the Iatrogenic Pancreatic Cancer Risk After Islet Autotransplantation in Mouse.

Iatrogenic pancreatic cancer metastasis after islet infusion is a potential risk of islet autotransplantation performed after pancreatectomy. To model this risk, islets and/or pancreatic exocrine clusters obtained from a genetically engineered mouse model for pancreatic ductal adenocarcinoma (the LSL-KrasG12D/+ ;LSL-Trp53R172H/+ ;Pdx-1-Cre, termed KPC mouse) were transplanted via the portal vein in syngeneic wild type (WT) severely diabetic recipients in the following treatment groups: group A (n = 11) received KPC exocrine clusters in volume equal to 250 islet equivalents (IEQs); group B (n = 12) received 250 WT IEQs mixed with KPC exocrine clusters (1:1 volume ratio); group C (n = 5) received 250 KPC IEQs, and group D (n = 7) received 250 WT IEQs. The incidence of hepatic metastasis was assessed by magnetic resonance imaging and histology over the 13 months of follow-up. Overall survival was not different in the four groups. No mice developed liver metastases during the follow-up. Two mice developed spontaneous tumors: a liver hepatocellular tumor in group A and a malignant lymphoma in group D. Islets and/or exocrine clusters obtained by KPC mouse, a model that develops pancreatic cancer with 100% penetrance, do not retain the same risk of tumor development when transplanted via the portal vein in a syngeneic diabetic recipient.

From nano to microcrystals: effects of different synthetic pathways on the defect architecture in heavily Gd-doped ceria.

The evolution of the defect structure and microstructure of heavily Gd-doped ceria (Ce1-µREµO2-y, 0.313 ≤ µ ≤ 0.438) for different synthetic pathways is investigated here to explore the way defects interact with each other in a composition range known to effectively hamper the application of the material as an electrolyte. Synchrotron radiation powder diffraction is exploited by combining conventional Rietveld analysis with the Pair Distribution Function to get a multiscale picture of defect structures, and it is combined with Raman spectroscopy to assess local scale interactions. Samples were prepared via both the sol-gel route and coprecipitation of oxalates by sintering the powders at different temperatures to obtain samples with different defect distributions and crystallite sizes, investigated using electron microscopy and Whole Powder Pattern Modelling from diffraction data. As a general scheme, increasing the doping amount transforms the fluorite structure of ceria into C-type Gd2O3. For samples annealed at and above 900 °C, containing crystals at least ∼100 nm in size, this transformation occurs through a mechanism involving first the formation of distorted Gd-rich droplets on the local scale, then the growth of extended C-type nanodomains. Nanoparticles, resulting from thermal treatments at lower temperature, are less distorted on the local scale and transform abruptly upon doping, without forming larger dopant-rich aggregations, from fluorite to the C-type. The annealing temperature not only acts on the sintering of the crystallites, it is also found to promote a radical change in the microstructure as a consequence of the preferential aggregation of oxygen vacancies.

Autologous Islet Transplantation in Patients Requiring Pancreatectomy: A Broader Spectrum of Indications Beyond Chronic Pancreatitis.

Islet autotransplantation (IAT) is usually performed in patients undergoing pancreatic surgery for chronic pancreatitis. In the present series, IAT was offered also to patients undergoing pancreatic surgery for both nonmalignant and malignant diseases, having either completion pancreatectomy as treatment for severe pancreatic fistulas (n = 21) or extensive distal pancreatectomy for neoplasms of the pancreatic neck (n = 19) or pancreatoduodenectomy because of the high risk of pancreatic fistula (n = 32). Fifty-eight of 72 patients who were eligible to this broader spectrum of indication actually received IAT. There was no evidence of a higher-than-expected rate of major complications for pancreatectomy. Forty-five patients receiving IAT were still alive at the time of the last scheduled follow-up (1375 ± 365 days). Eighteen (95%) of 19 and 11 (28%) of 39 patients reached insulin independence after partial or total pancreatectomy, respectively. The metabolic results were dependent on the transplanted islet mass. Thirty-one of 58 patients had malignant diseases of the pancreas or periampullary region, and only three patients developed ex novo liver metastases after IAT (median follow-up 914 ± 382 days). Our data demonstrate the feasibility, efficacy, and safety of IAT for a broader spectrum of clinical indications beyond chronic pancreatitis.

Screening for gestational diabetes in the Lombardy region: A population-based study.

AIM: As the treatment of hyperglycaemia during pregnancy with diet or insulin reduces the risk of adverse maternal outcomes and perinatal complications, screening for gestational diabetes mellitus (GDM) is included, albeit to variable extents, in all guidelines of care for pregnant women. The aim of the present investigation was to estimate the proportion of pregnancies screened for GDM in Lombardy between 2007 and 2010, and to identify predictors of screening. METHODS: A retrospective cross-sectional study using regional healthcare utilization databases of Lombardy was conducted. The study included all residents of Lombardy without pregestational diabetes who delivered between 1 January 2007 and 31 December 2010. The proportion of pregnancies with at least one screening test for GDM was calculated, along with the odds ratios and 95% confidence intervals associated with selected covariates for GDM screening. RESULTS: Of the 362,818 pregnancies included in the sample, 30% were screened for GDM. The proportion of pregnancies screened increased slightly from 2007 (27%) to 2010 (33%) and with maternal age (from 28% among women<25 years to 32% among those ≥35 years), and varied widely across local health management organizations (HMOs) of residence (range: 20% to 68%). Socioeconomic indicators (education, immigrant status), obstetric history and prepregnancy hypertension were independent predictors of GDM screening. CONCLUSION: The study finding of a low rate of pregnant women screened for GDM among residents of Lombardy supports the need for programmes to improve training of healthcare professionals, to raise women's awareness of GDM and to eliminate barriers to GDM screening.

The risk of preeclampsia beyond the first pregnancy among women with type 1 diabetes parity and preeclampsia in type 1 diabetes.

AIM: To estimate the incidence of preeclampsia (PE) among nulliparous and multiparous patients with type 1 diabetes and to study predictors of PE. METHODS: We prospectively collected data on all pregnancies of patients with pregestational type 1 diabetes, followed at our Prenatal Medicine Unit between 1993 and 2008. Medical records were prospectively reviewed by two obstetricians for maternal demographics, pregnancy data, maternal and fetal outcomes. Data were analyzed according to the development of PE and parity. RESULTS: We identified and collected data on 291 eligible pregnancies (195 among nulliparae and 96 among multiparae). The incidence of PE was 9.2% (95% CI: 5.6-14.2) among nulliparae and 9.4% (95% CI: 4.4-17.0) among multiparae. Patients who developed PE had higher HbA1c during pregnancy compared to patients who did not (p=0.026 among nulliparae and p=0.032 among multiparae). Chronic hypertension [OR 17.12 (3.22, 91.00)], microalbuminuria at the beginning of the pregnancy [OR 3.77 (1.22, 11.61)], weight gain during pregnancy [OR 1.13 (1.04, 1.23)] and HbA1c in the first trimester [2.81 (1.12, 7.05)], but not parity, were significant predictors of PE. CONCLUSIONS: Among patients with type 1 diabetes the incidence of PE was similar among nulliparae and multiparae, unlikely in the general population where PE is a disease of the first pregnancy. An increased risk of PE should be assumed for both nulliparous and multiparous women with pregestational diabetes.

High levels of donor CCL2/MCP-1 predict graft-related complications and poor graft survival after kidney-pancreas transplantation.

In this study we analyzed the role of CCL2, a member of the chemokine family, in early graft damage. Using simultaneous kidney-pancreas transplantation (SPK) as a model, we showed that brain death significantly increases circulating CCL2 levels in humans. We found that in such situations, high donor CCL2 levels (measured before organ recovery and at the onset of cold preservation) correlate with increased postreperfusion release of CCL2 by both the graft and recipient throughout the week following transplantation (n = 28). In a retrospective study of 77 SPK recipients, we found a significant negative association between high donor levels of CCL2 and graft survival. Decreased survival in these patients is related to early posttransplant complications, including a higher incidence of pancreas thrombosis and delayed kidney function. Taken together our data indicate that high CCL2 levels in the donor serum predict both an increase in graft/recipient CCL2 production and poor graft survival. This suggests that the severity of the inflammatory response induced by brain death influences the posttransplant inflammatory response, independent of subsequent ischemia and reperfusion.

Hypokalemic periodic paralysis in a patient with acquired growth hormone deficiency.

CONTEXT: Hypokalemic periodic paralysis (HypoPP) is a rare disorder consisting of sudden episodes of muscle weakness with areflexia involving all four limbs, which spontaneously resolve within several hours or days. Primary HypoPP is genetically determined, while secondary acquired HypoPP has been described in association with thyreotoxycosis, hyperaldosteronism, kidney diseases, diuretics and liquorice abuse, gastrointestinal potassium loss, or cysplatinum therapy. OBJECTIVE: To report a case of HypoPP associated with GH deficiency. PATIENT: A 33 yr-old man with hypopituitarism and diabetes insipidus secondary to pituitary stalk-localized sarcoidosis, and documented HypoPP episodes. CLINICAL PRESENTATION: Neurologic exam outside HypoPP episodes was normal. Needle electromyography was normal without myotonia or other spontaneous electric activity. Muscle biopsy documented a vacuolar myopathy with tubular aggregates. However, genetic analysis ruled out common mutations of the voltage-gated calcium channel observed in primary HypoPP. Common causes of secondary HypoPP were also ruled out. The patient was diagnosed with severe GH deficiency with modest fasting hyperinsulinemia and insulin resistance and started on GH replacement therapy, an alpha-glucosidase inhibitor (acarbose) and a diet low in simple carbohydrates. CONCLUSIONS: GH replacement therapy, acarbose and a diet low in simple carbohydrates resulted in the complete long-term (>2 yr) remission of HypoPP episodes. This is consistent with the hypothesis that the hyperinsulinemia associated to GH deficiency may trigger HypoPP episodes by increasing Na+/K+ ATPase activity and K+ transport into the intracellular compartment with subsequent hypokalemia.

Insulin receptor antibodies inhibit insulin uptake by the liver: in vivo 123I-insulin scintigraphic scanning and in vitro characterization in autoimmune hypoglycemia.

BACKGROUND: Insulin receptor antibodies can induce severe hypoglycemia or insulin resistance in rare autoimmune syndromes. In vitro properties of these antibodies occasionally explain the clinical features of the syndrome, but direct evidence of their in vivo activity is poor. We studied a 58-year-old male with rheumatoid arthritis who presented with hypoglycemic coma. METHODS AND RESULTS: Antibodies were detected by inhibition of 125I-insulin binding to human insulin receptor-3T3 cells by the patient's serum. By immunofluorescence, they were immunoglobulin G of all four subclasses, immunoprecipitated insulin receptors from biotin-labeled cells, and triggered phosphorylation of the beta subunit of the insulin receptor. Insulin binding on the patient's red blood cells was markedly reduced. A biodistribution study after intravenous 123I-Tyr A14 insulin showed a marked inhibition of tracer uptake by the liver, reaching 10% of the injected dose (controls, mean +/- SD, 21.1 +/- 1.7%; n = 10). Time activity curves generated on the liver and on the heart were parallel, with a T1/2 of 11.5 minutes for both, suggesting that no specific uptake occurred in the liver, where tracer activity represented only the blood pool. Clearance of insulin from the blood was indeed slower than in controls and mainly occurred through the kidneys. Analysis of plasma 123I-insulin immunoreactivity and trichloroacetic acid precipitate showed that insulin degradation did not occur as in normal controls. CONCLUSIONS: In this patient with hypoglycemic syndrome, insulin receptor antibodies with in vitro insulin-like activity are capable of blocking in vivo the access of insulin to the liver receptor compartment, as directly demonstrated by the markedly altered biodistribution of intravenously injected 123I-insulin.

Z-2 microsatellite allele is linked to increased expression of the aldose reductase gene in diabetic nephropathy.

Epidemiological studies support the hypothesis that genetic factors modulate the risk for diabetic nephropathy (DN). Aldose reductase (ALDR1), the rate-limiting enzyme in the polyol pathway, is a potential candidate gene. The present study explores the hypothesis that polymorphisms of the (A-C)n dinucleotide repeat sequence, located 2.1 kb upstream of the transcription start site, modulate ALDR1 gene expression and the risk for DN. We conducted studies at two different institutions, the University of New Mexico Health Sciences Center (UNMHSC), and the Istituto Scientifico H San Raffaele (HSR). There were four groups of volunteers at UNMHSC: group I, normal subjects; group II, patients with insulin-dependent diabetes mellitus (IDDM) without DN; group III, IDDM with DN; and group IV, nondiabetics with kidney disease. At HSR we studied volunteers in groups I, II, and III. ALDR1 genotype was assessed by PCR and fluorescent sequencing of the (A-C)n repeat locus, and ALDR1 messenger ribonucleic acid (mRNA) was measured by ribonuclease protection assay in peripheral blood mononuclear cells. At UNMHSC we identified 10 alleles ranging from Z-10 to Z+8. The prevalence of the Z-2 allele among IDDM patients was increased in those with DN. Sixty percent of group III and 22% of group II were homozygous for Z-2. Moreover, 90% and 67% of groups III and II, respectively, had 1 or more copy of Z-2. In contrast, among nondiabetics, 19% of group IV and 3% of group I were homozygous for Z-2, and 69% and 32%, respectively, had 1 copy or more of Z-2. Among diabetics, homozygosity for the Z-2 allele was associated with renal disease [odds ratio (OR), 5.25; 95% confidence interval, 1.71-17.98; P = 0.005]. ALDR1 mRNA levels were higher in patients with DN (group III; 0.113 +/- 0.050) than in group I (0.068 +/- 0.025), group II (0.042 +/- 0.020), or group IV (0.015 +/- 0.011; P < 0.01). Among diabetics, ALDR1 mRNA levels were higher in Z-2 homozygotes (0.098 +/- 0.06) and Z-2 heterozygotes (0.080 +/- 0.04) than in patients with no Z-2 allele (0.043 +/- 0.02; P < 0.05). In contrast, among nondiabetics, ALDR1 mRNA levels in Z-2 homozygotes (0.034 +/- 0.04) and Z-2 heterozygotes (0.038 +/- 0.03) were similar to levels in patients without a Z-2 allele (0.047 +/- 0.03; P = NS). At HSR we identified eight alleles ranging from Z- 12 to Z+2. The prevalence of the Z-2 allele was higher in group III than in group II. In group III, 43% of the patients were homozygous for Z-2, and 81% had one copy or more of the Z-2 allele. In contrast, in group II, 4% were homozygous for Z-2, and 36% had one copy or more of the Z-2 allele. IDDM patients homozygous for Z-2 had an increased risk for DN compared with those lacking the Z-2 allele (OR, 18; 95% confidence interval, 2-159). IDDM patients who had one copy or more of Z-2 had increased risk (OR, 7.5; 95% confidence interval, 1.9-29.4) for DN compared with those without the Z-2 allele. These results support our hypothesis that environmental-genetic interactions modulate the risk for DN. Specifically, the Z 2 allele, in the presence of diabetes and/or hyperglycemia, is associated with increased ALDR1 expression. This interaction may explain the observed association between the Z-2 allele and DN.

Imaging of the buffering effect of insulin antibodies in the autoimmune hypoglycemic syndrome.

Insulin autoimmune hypoglycemia is characterized by recurrent hypoglycemia and high levels of immunoreactive insulin in the presence of insulin autoantibodies. The mechanisms inducing hypoglycemia are largely unknown. An [123I]insulin scintigraphic scanning was performed to directly demonstrate the effect of antibodies on insulin biodistribution in one patient with this syndrome both before and after treatment. The patient had insulin autoantibodies IgG3 lambda, which had a single site dissociation constant (Kd = 10(-7) mol/L, by Scatchard analysis), a very fast dissociation rate of immune complexes, and a very rapid association of [125I]insulin. Insulin receptors on red blood cells were down-regulated. The [123I]insulin scintigraphic study imaged the buffering effect of antibodies on insulin bioavailability. [123I]Insulin was not removed from the blood, and no liver or kidney uptake of the hormone occurred. The frequency and severity of hypoglycemic episodes required treatment. Insulin antibody levels decreased and [123I]insulin biodistribution improved after treatment with plasmapheresis and prednisone. Improved hormone bioavailability was further evidenced by the reduction in the hypoglycemic delay after i.v. insulin from 90 min before any treatment to 60 min after plasmapheresis and 30 min after steroid administration. Glucose tolerance was normal after treatment. Plasmapheresis followed by steroid treatment can lower the insulin antibody concentration, abolish severe hypoglycemia, and improve insulin biodistribution and glucose tolerance in insulin autoimmune hypoglycemia.

A method for assessing catheter patency in implanted pumps for long-term intraperitoneal insulin delivery.

Catheter complications are a common problem during long-term insulin therapy with implanted pumps. The purpose of this study was to test the feasibility of imaging intraperitoneal catheters with technetium (Tc) 99m in implantable devices for insulin delivery. Testing physical stability of an insulin/Tc 99 mixture did not show formation of insulin aggregates during a period up to 48 h on a rotating wheel. Five hundred microCurie (equal to 18 MBq) of Tc 99m were injected in the flush port of a pump for intraperitoneal insulin delivery implanted in patients with type I (insulin dependent) diabetes mellitus, and gamma camera images were obtained for 30 min. In patent catheters the tracer rapidly imaged the whole length of the catheter while in occluded catheters the tracer remained in the flush port, imaging only the portion of the catheter before the occlusion. In patent catheters in which insulin absorption was impaired, the tracer rapidly imaged the whole length of the catheter, but its removal from the peritoneum was delayed. Tc 99m imaging of intraperitoneal catheters for insulin delivery can be used to assess catheter patency and impaired delivery into the peritoneal cavity.

Catheter survival during long-term insulin therapy with an implanted programmable pump. The Implantable Insulin Pump Trial Study Group.

OBJECTIVE: To survey catheter complications and to analyze catheter survival during long-term intraperitoneal and intravenous insulin therapy with an implanted programmable pump with a sideport. RESEARCH DESIGN AND METHODS: Catheter occlusions were documented by measuring dynamic catheter resistance. Catheter migrations or breaks were demonstrated by X ray. When flushing the catheter with buffer solution through the sideport failed to clear the occlusion, catheters were replaced or laparoscopy was performed for the excision of fibrous tissue growth. Broken or migrated catheters were replaced. RESULTS: Occlusions were the most common catheter complications, and the majority of them (79% intraperitoneal and 84% intravenous) were cleared by flushing the catheter. Survival at 3 years was significantly higher for intraperitoneal catheters compared with intravenous catheters (60% intraperitoneal and 22% intravenous). CONCLUSIONS: Nonsurgical management of catheter occlusions contributed to extend catheter lifetime. Intraperitoneal catheters have a lower morbidity and a higher survival than intravenous catheters.

Long-term therapy of IDDM with an implantable insulin pump. The Implantable Insulin Pump Trial Study Group.

OBJECTIVE: To examine the long-term benefits and risks of treatment of IDDM with an implantable programmable insulin pump. RESEARCH DESIGN AND METHODS: Seventy-six patients with IDDM were studied at nine clinical centers. After 3-4 months of intensive subcutaneous therapy, the Infusaid Model 1000 pump was implanted, and insulin was delivered either intraperitoneally or intravenously for an average of 39.6 +/- 10 months (251 patient-years). Data was collected for glycemic control, lipid levels, weight gain, insulin requirements, adverse events, and quality of life. Sixty-three patients were also followed for 8.5 +/- 6.3 months (45 patient-years) after pump therapy was discontinued. RESULTS: Mean quarterly HbA1c fell with subcutaneous intensive therapy and remained stable on implantable pump therapy between 6.9 and 7.5%. Severe hypoglycemia was relatively rare, with only 4 episodes/100 patient-years of implantable pump therapy. This rate was significantly less than with subcutaneous intensive therapy before implantable pump initiation (33 episodes/100 patient-years) or after discontinuation of implantable pump therapy (36/100 patient-years) (P < 0.003). Weight did not increase significantly in the 1st year of therapy, but increased by 2.0 +/- 4.3 kg after 3 years of therapy. There were no significant differences in metabolic control or adverse events between intraperitoneal and intravenous insulin therapy except for minor differences in lipid levels and the more frequent development of catheter obstruction with intravenous delivery. Most pump slow-downs and catheter occlusions were corrected noninvasively. Quality of life, as measured by the Diabetes Control and Complications Trial instrument, showed high satisfaction and improved impact scores. CONCLUSIONS: Long-term implantable pump therapy maintained HbA1c in a range similar to intensive subcutaneous therapy, but with fewer episodes of severe hypoglycemia. Although pump and catheter occlusions remain a limitation, patient satisfaction with implantable pump therapy remains high.

Use of an integrated sideport for diagnosis and management of decreased flow rates in a programmable implanted insulin delivery system. Implantable Insulin Pump Trial Study Group.

The aim of this study was to develop procedures for the diagnosis and nonsurgical management of decreased insulin flow in an implantable programmable pump for long-term intraperitoneal or intravenous insulin delivery featuring a sideport. Patency of the catheter lumen was tested by measuring the time needed for sideport pressure to decrease by 50% after the injection of 0.1 ml of buffer solution. Pumping unit performances were assessed by measuring the volume of pump pulses after diverting the pump flow at the sideport. A catheter flush with buffer solution through the sideport was effective in clearing 79% of intraperitoneal and 84% of intravenous catheter occlusions. Washing the pumping unit with an alkaline solution after diverting pump flow at the sideport was effective in dissolving insulin aggregates inside the pumping unit and in restoring normal pump flow. These procedures were associated with a 1.3% rate of hypoglycemic episodes.

Insulin antibodies do not preclude optimization of metabolic control in women with IDDM during pregnancy.

OBJECTIVE: To evaluate whether the presence of insulin antibodies (IAs) may preclude the optimization of metabolic control during pregnancy and affect outcome in women with IDDM. RESEARCH DESIGN AND METHODS: IAs were measured by radiobinding assay in 44 women with IDDM referred to the Diabetes and Pregnancy Outpatients' Clinic during 46 pregnancies. Age, duration of IDDM, metabolic control (HbA1c, mean pre- and postprandial capillary blood glucose, frequency of hypo- or hyperglycemia), insulin requirement at 1st and 3rd trimester of pregnancy, BM1, and weight gain were recorded. Neonatal variables such as gestational age, weight, length, and the presence at birth of either hypoglycemia, hypocalcemia, or jaundice requiring phototherapy were also considered. RESULTS: IAs correlated positively with insulin requirement (P < 0.05) and negatively with HbA1c at term (P < 0.01). Patients with IA levels > or = 40% insulin binding (8 of 46) had a higher insulin requirement and lower preprandial capillary blood glucose at the beginning of pregnancy but not at term (P < 0.005), whereas they had lower HbA1c at term than did patients with low IA levels (P < 0.01). IA levels decreased slightly at term (P = 0.007). IA levels > or = 40% were not associated with a higher rate of hypo- or hyperglycemic episodes or with diabetic complications or thyreopathy. No correlation was found between 1A levels and any of the neonatal variables considered. CONCLUSIONS: The presence of IAs does not preclude optimization of metabolic control during pregnancy and is compatible with a favourable outcome.

In vivo metabolic effects of insulin-like growth factor-I not mediated through the insulin receptor.

Patients with mutations affecting insulin receptor function may maintain some degree of metabolic control. The hypothesis has been put forth that in these patients, fuels may be metabolized through pathways (i.e. receptor activation) that become relevant in such abnormal conditions. The aim of our study was to evaluate the metabolic effects of insulin-like growth factor-I (IGF-I) in a 19-yr-old patient with homozygous mutation of the insulin receptor alpha-subunit. Her metabolic and hormonal features were marked hyperglycemia (11-33 mmol/L) and hyperinsulinemia (1000-2000 pmol/L); normal free fatty acids and lactate; low IGF-I; glycerol, alanine, and pyruvate below the normal range; and elevated beta-hydroxybutyrate. Unlike diabetic ketoacidosis, no triglyceride or protein breakdown was present, suggesting a compensatory mechanism, possibly sustained by the insulin concentration acting on IGF-I receptors. Subcutaneous administration of IGF-I (40, 80, and 120 micrograms/kg), although not affecting plasma glucose, resulted in a rapid decrease in free fatty acids and prevented the rise of beta-hydroxybutyrate levels compared to placebo. Therefore, IGF-I can exert direct metabolic effects in vivo, probably through activation of its own receptor, even at a concentration not affecting blood glucose levels. Furthermore, these findings are consistent with the hypothesis that IGF-I receptors may be activated by high insulin levels, providing lipid and protein regulation in patients with nonfunctional insulin receptors.

Intraperitoneal insulin absorption after long-term intraperitoneal insulin therapy.

OBJECTIVE: To evaluate insulin absorption through the peritoneal membrane after long-term intraperitoneal insulin therapy using an implanted programmable device. RESEARCH DESIGN AND METHODS: Seven insulin-dependent diabetes mellitus (IDDM) patients implanted with a programmable pump were studied after 3 and 30 months of intraperitoneal insulin therapy. A 20-min square wave infusion of 15 IU of insulin was administered in the peritoneal space, and plasma glucose and plasma free insulin levels were monitored for 180 min. Hypoglycemia was prevented by intravenous glucose infusion. RESULTS: After 30 months of intraperitoneal insulin therapy, plasma free insulin profiles following the administration of insulin in the peritoneal space were similar to those observed at the beginning of this mode of therapy. CONCLUSIONS: In IDDM patients, intraperitoneal insulin absorption does not change after long-term intraperitoneal insulin therapy using an implanted device.

Peritoneal and subcutaneous absorption of insulin in type I diabetic subjects.

We and others have shown that in type I diabetes, ip insulin delivery results in lower free insulin levels than sc delivery. The aim of this study was to compare the rate of appearance of insulin in the peripheral circulation during ip and sc insulin administration in type I diabetes, in steady state and nonsteady state. To do this, we determined free insulin levels during ip or sc infusion as well as the impulse response of the insulin system after iv injection of a 6-nmol bolus of insulin. Twelve hours after a constant basal insulin infusion (5.5 +/- 1.4 nmol/h) was started, five C-peptide-negative type I diabetic subjects showed a lower systemic rate of appearance of insulin (expressed as a percentage of the administered dose) with ip than sc administration (27 +/- 6% vs. 40 +/- 10%; P < 0.001). In nonsteady state, when the infusion rate was increased from basal to 15 nmol/h (0-150 min) and subsequently to 42 nmol/h (150-300 min), the percent increase in insulin's systemic rate of appearance was higher with ip than sc infusion (P < 0.05 from 60-150 min; P < 0.01 from 150-300 min), indicating faster absorption. Thus, we conclude that insulin is more rapidly absorbed from the peritoneal cavity than from sc tissue. However, with ip administration, a sizable amount of insulin, once absorbed, is extracted before reaching the peripheral circulation, most likely by the liver. This is indirect evidence that ip insulin delivery results in a portal-peripheral insulin gradient in humans.