Major Bleeding Events in Hospitalized COVID-19 Patients: A Retrospective Observational Study

Thromboprophylaxis/anticoagulation treatment is often required in hospitalized COVID-19 patients. We aimed to estimate the prevalence of major bleeding events in hospitalized COVID-19 patients. This was a retrospective observational study including all COVID-19 hospitalized patients ≥18 years of age at one reference center in northern Italy. The crude prevalence (between February 2020-2022) of major bleeding events was estimated as the number of major bleeding episodes divided by patients at risk. Uni- and multivariable Cox models were built to assess factors potentially associated with major bleeding events. Twenty-nine (0.98%) out of 2,945 COVID-19 patients experienced a major bleeding event [prevalence of 0.55% (95%CI 0.37-0.79)], of which five were fatal. Patients who experienced a major bleeding event were older [78 years (72-84 IQR) vs. 67 years (55-78 IQR), p-value < 0.001] and more frequently exposed to anti-aggregating therapy (44.8% vs. 20.0%, p-value 0.002) when compared to those who did not. In the multivariable Cox model, age [per 1 year more AHR 1.05 (CI95% 1.02-1.09)] was independently associated with an increased risk of major bleeding events. A strict monitoring of older hospitalized COVID-19 patients is warranted due to the risk of major bleeding events.

Detection and typization of HPV genotypes in subjects with oral and upper respiratory tract lesions, Milan, Italy

BACKGROUND

Oral human papillomavirus (HPV) is common among healthy individuals but causes and implications of persistent infections are under evaluation in the pathogenesis of head and neck neoplasms.

METHODS

This was a retrospective study evaluating the prevalence of high-risk (HR), probable HR and low-risk (LR) HPV types in patients reporting signs/symptoms of oral and upper respiratory tract lesions. Individuals attending between 2019 and 2022 a University Hospital in Milan, Italy, with risk factors for HPV (unprotected oral sex and/or previous documentation of HPV infection in oral and upper respiratory tract and/or another anatomical site) were included.

RESULTS

Fourteen out of 110 (12.7%) individuals tested positive for HPV DNA. The prevalence of HR-HPV and LR-HPV was 3.6% (4/110) and 9.1% (10/110), respectively. No probable/possible HR-HPV was detected. Specifically, 10/110 (9.1%) were diagnosed with 1 LR-HPV genotype, 3/110 (2.7%) were infected with 1 HR-HPV and 1/110 had 3 concomitant HR-HPV types. HPV 16 (2.7%, 3/110) and 6 (4.5%, 5/110) were the most common HR and LR types, respectively. One patient positive for HPV 16, 33 and 35 was diagnosed with cancer at the base of the tongue. Two individuals among those who tested positive for HPV DNA reported previous HPV vaccination.

CONCLUSIONS

Our data, in line with observations from previous prevalence studies, support the potential role of HPV in head and neck neoplasms. HPV DNA testing should be performed in patients presenting lesions in oral/respiratory tracts and risk factors for HPV. Improvement in HPV vaccination coverage is warranted.

Bloodstream Infections in Intensive Care Unit during Four Consecutive SARS-CoV-2 Pandemic Waves

Critically ill COVID-19 patients are at an increased risk of bloodstream infections (BSIs). We performed a retrospective observational single-center study on COVID-19 patients admitted to intensive care unit (ICU) to assess the incidence of BSIs in four consecutive periods: 21 February-31 July 2020 (W1), 1 August 2020-31 January 2021 (W2), 1 February-30 September 2021 (W3) and 1 October 2021 and 30 April 2022 (W4). BSIs that occurred 48 h after ICU admission were included. The crude incidence of BSIs was estimated by means of Poisson distribution normalized to 1000 patient-days. A total of 404 critically ill COVID-19 patients were admitted to ICU, of whom 284 (61%) developed at least one episode of BSI with an overall crude incidence of 87 events every 1000 patient-days (95% CI 77-98) without a significant difference in consecutive epidemic periods (p = 0.357). Gram-positive bacteria were the most frequent etiological agents of BSIs, contributing to 74.6% episodes. A progressive decrease in BSIs due to Enterococcus spp. was observed (W1 57.4%, W2 43.7%, W3 35.7% and W4 32.7%; p = 0.004). The incidence of BSIs remained stable during different epidemic periods. Enterococcus spp. prevalence was significantly reduced, although still accounted for one third of BSIs in more recent epidemic periods.

Clinical efficacy of the first two doses of anti-SARS-CoV-2 mRNA vaccines in solid cancer patients

INTRODUCTION

Cancer patients are frail individuals, thus the prevention of SARS-CoV-2 infection is essential. To date, vaccination is the most effective tool to prevent COVID-19. In a previous study, we evaluated the immunogenicity of two doses of mRNA-based vaccines (BNT162b2 or mRNA-1273) in solid cancer patients. We found that seroconversion rate in cancer patients without a previous exposure to SARS-CoV-2 was lower than in healthy controls (66.7% vs. 95%, p = 0.0020). The present study aimed to evaluate the clinical efficacy of the vaccination in the same population.

METHODS

This is a single-institution, prospective observational study. Data were collected through a predefined questionnaire through phone call in the period between the second and third vaccine dose. The primary objective was to describe the clinical efficacy of the vaccination, defined as the percentage of vaccinated subjects who did not develop symptomatic COVID-19 within 6 months after the second dose. The secondary objective was to describe the clinical features of patients who developed COVID-19.

RESULTS

From January to June 2021, 195 cancer patients were enrolled. Considering that 7 (3.59%) patients tested positive for SARS-CoV-2 and 5 developed symptomatic disease, the clinical efficacy of the vaccination was 97.4%. COVID-19 disease in most patients was mild and managed at home; only one hospitalization was recorded and no patient required hospitalization in the intensive care unit.

DISCUSSION

Our study suggests that increasing vaccination coverage, including booster doses, could improve the prevention of infection, hospitalization, serious illness, and death in the frail population of cancer patients.

Concomitant diagnosis of sexually transmitted infections and human monkeypox in patients attending a sexual health clinic in Milan, Italy

In 2022, many monkeypox (MPX) outbreaks have been documented in countries where MPX was not endemic. It spread all around the world, especially in European Union and United States. While MPX is classically considered to be transmitted through close contact with lesions, the hypothesis of sexual transmission has been proposed. This study considered a total of 49 patients suspected for MPX that were also tested for other sexually transmitted infections (STIs), including Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, and Trichomonas vaginalis. The data from coinfected patients suggested that MPXV and STIs might share the same route of inoculum, corroborating the hypothesis of possible sexual transmission for the emerging poxvirus. And like any other STI, MPX should be considered without stigmatization.

Isolation of viable monkeypox virus from anal and urethral swabs, Italy, May to July 2022

Anal and urethral samples from confirmed cases of monkeypox were screened for monkeypox virus (MPXV) by real-time PCR. Isolation of the virus was subsequently attempted in cell culture. Actively-replicating virus was demonstrated in 13 of 18 and 11 of 15 PCR-positive anal and urethral swabs, respectively, collected within 7 days from symptoms onset. Two asymptomatic secondary cases had detectable MPXV genetic material in urethral secretion and for one, MPXV was successfully isolated, supporting a potential MPXV sexual transmission hypothesis.

Challenges in Diagnosing COVID-19-Associated Pulmonary Aspergillosis in Critically Ill Patients: The Relationship between Case Definitions and Autoptic Data

Critically ill COVID-19 patients can develop invasive pulmonary aspergillosis (CAPA). Considering the weaknesses of diagnostic tests/case definitions, as well as the results from autoptic studies, there is a debate on the real burden of aspergillosis in COVID-19 patients. We performed a retrospective observational study on mechanically ventilated critically ill COVID-19 patients in an intensive care unit (ICU). The primary objective was to determine the burden of CAPA by comparing clinical diagnosis (through case definitions/diagnostic algorithms) with autopsy results. Twenty patients out of 168 (11.9%) developed probable CAPA. Seven (35%) were females, and the median age was 66 [IQR 59–72] years. Thirteen CAPA patients (65%) died and, for six, an autopsy was performed providing a proven diagnosis in four cases. Histopathology findings suggest a focal pattern, rather than invasive and diffuse fungal disease, in the context of prominent viral pneumonia. In a cohort of mechanically ventilated patients with probable CAPA, by performing a high rate of complete autopsies, invasive aspergillosis was not always proven. It is still not clear whether aspergillosis is the major driver of mortality in patients with CAPA.

Mortality rates among COVID-19 patients hospitalised during the first three waves of the epidemic in Milan, Italy: A prospective observational study

Introduction

This paper describes how mortality among hospitalised COVID-19 patients changed during the first three waves of the epidemic in Italy.

Methods

This prospective cohort study used the Kaplan-Meier method to analyse the time-dependent probability of death of all of the patients admitted to a COVID-19 referral centre in Milan, Italy, during the three consecutive periods of: 21 February-31 July 2020 (first wave, W1), 1 August 2020–31 January 2021 (second wave, W2), and 1 February-30 April 2021 (third wave, W3). Cox models were used to examine the association between death and the period of admission after adjusting for age, biological sex, the time from symptom onset to admission, disease severity upon admission, obesity, and the comorbidity burden.

Results

Of the 2,023 COVID-19 patients admitted to our hospital during the study period, 553 (27.3%) were admitted during W1, 838 (41.5%) during W2, and 632 (31.2%) during W3. The crude mortality rate during W1, W2 and W3 was respectively 21.3%, 23.7% and 15.8%. After adjusting for potential confounders, hospitalisation during W2 or W3 was independently associated with a significantly lower risk of death than hospitalisation during W1 (adjusted hazard ratios [AHRs]: 0.75, 95% confidence interval [CI] 0.59–0.95, and 0.58, 95% CI 0.44–0.77). Among the patients aged >75 years, there was no significant difference in the probability of death during the three waves (AHRs during W2 and W3 vs W1: 0.93, 95% CI 0.65–1.33, and 0.88, 95% CI 0.59–1.32), whereas those presenting with critical disease during W2 and W3 were at significantly lower risk of dying than those admitted during W1 (AHRs 0.61, 95% CI 0.43–0.88, and 0.44, 95% CI 0.28–0.70).

Conclusions

Hospitalisation during W2 and W3 was associated with a reduced risk of COVID-19 death in comparison with W1, but there was no difference in survival probability in patients aged >75 years.

Hospitalisation for monkeypox in Milan, Italy

During the current multi-country outbreak of human monkeypox the hospitalisation rate observed in Milan, Italy was 8.8%. Bacterial superinfection and severe perianal pain were the main cause of hospitalisation requiring antibiotic treatment and analgesic therapy. One patient was treated with Cidofovir. All hospitalised patients were discharged and the outcome was favourable with full recovery.

Multicentre Trial of a Programmable Implantable Insulin Pump in Type I Diabetes

Programmable implantable pumps permitting variable-rate intraperitoneal insulin infusion are currently investigated as a potential alternative to subcutaneous insulin therapy. An improved version of the Siemens implantable system has been evaluated in 6 European centres on 31 type I diabetic patients treated for 10–30 months. Contrary to other pump models there were no proven pump malfunctions and only one no-flow reduction unrelated to catheter obstruction. The latter resulted in 12 surgical catheter replacements. There were 2.0 incidents of programmer malfunctions per patient-year easily managed by reconfiguration or replacement. Insulin remained clear and active in the pump reservoir and glycaemic control remained in the near-normoglycaemic range. Thus, insulin therapy with the Siemens implantable pump is feasible and effective up to 2.5 years.

Hybrid minimally invasive esophagectomy for cancer: impact on postoperative inflammatory and nutritional status

The purpose of this case-control study was to evaluate the impact of hybrid minimally invasive esophagectomy for cancer on surgical stress response and nutritional status. All 34 consecutive patients undergoing hybrid minimally invasive esophagectomy for cancer at our surgical unit between 2008 and 2013 were retrospectively compared with 34 patients undergoing esophagectomy with open gastric tubulization (open), matched for neoadjuvant therapy, pathological stage, gender and age. Demographic data, tumor features and postoperative course (including quality of life and systemic inflammatory and nutritional status) were compared. Postoperative course was similar in terms of complication rate. Length of stay in intensive care unit was shorter in patients undergoing hybrid minimally invasive esophagectomy (P = 0.002). In the first postoperative day, patients undergoing hybrid minimally invasive esophagectomy had lower C-reactive protein levels (P = 0.001) and white cell blood count (P = 0.05), and higher albumin serum level (P = 0.001). In this group, albumin remained higher also at third (P = 0.06) and seventh (P = 0.008) postoperative day, and C-reactive protein resulted lower at third post day (P = 0.04). Hybrid minimally invasive esophagectomy significantly improved the systemic inflammatory and catabolic response to surgical trauma, contributing to a shorter length of stay in intensive care unit.

Target gene expression signatures in neutrophils and lymphocytes from cattle administered with dexamethasone at growth promoting purposes

The glucocorticoid dexamethasone (DEX), when used as a growth promoter, cause morphological and functional alterations in cattle lymphoid organs and cells. In the present experiment, the transcriptional effects of an illicit DEX protocol upon six target genes were investigated in cattle neutrophils (NEU) and lymphocytes (LFC). Blood samples were taken before (T(0)) and 2, 3, 10, 19, 31 and 43 days from the beginning of DEX administration (T(1)-T(6)). Leukocytes were counted and cells isolated by gradient centrifugation; then, glutathione peroxidase 1 and 3 (GPX1 and GPX3), glucocorticoid receptor alpha (GRα), l-selectin, nuclear factor κB, subunit p65 (NFκB) and tumor necrosis factor alpha (TNFα) mRNA amounts were measured through a quantitative Real Time RT-PCR approach. A significant change vs controls in NEU/LFC ratio was noticed from T(3) forward. Compared to T(0), DEX significantly increased to a variable extent all candidate gene mRNAs abundances in NEU; in contrast, only l-selectin, GRα and GPX1 were significantly up-regulated in LFC. Present results suggest that illicit DEX affects transcription in cattle immune cells, that might be considered as a promising surrogate tissue for the screening of DEX abuse in cattle farming.

Effect of lercanidipine compared with ramipril on albumin excretion rate in hypertensive Type 2 diabetic patients with microalbuminuria: DIAL study (diabete, ipertensione, albuminuria, lercanidipina)

Microalbuminuria and hypertension are risk factors for diabetic nephropathy in Type 2 diabetic patients. Recent data suggest that blockade of the renin-angiotensin system slows the progression of diabetic nephropathy; in contrast, the results on the renoprotective effect of calcium channel antagonists are conflicting. We evaluated the effectiveness of lercanidipine, in comparison with ramipril, on the reduction in albumin excretion rate (AER) and blood pressure in mild-to-moderate hypertensive patients with Type 2 diabetes and persistent microalbuminuria. A total of 277 patients were enrolled in a multicentric, randomized, double-blind, active-controlled, parallel-group trial; 180 were randomized to receive 10-20 mg/day of lercanidipine or 5-10 mg/day of ramipril and followed up for 9-12 months. The primary outcome was the change in AER from baseline. After 9-12 months of follow-up, a reduction in AER of -17.4+/-65 microg/min (p<0.05) and -19.7+/-52.5 (p<0.05) in the lercanidipine and ramipril group, respectively, was observed, without differences between the groups. A significant reduction in systolic and diastolic blood pressure was observed in both the lercanidipine and ramipril-based treatment groups (p<0.0001 for both). This study demonstrated that treatment with lercanidipine 10-20 mg/day does not worsen albuminuria in microalbuminuric Type 2 diabetic patients with hypertension. Indeed, both lercanidipine and ramipril treatments resulted in a significant reduction in AER without a statistically significant difference between the two groups.

Field experiences in the control of avian influenza outbreaks in densely populated poultry areas

From 1997 to 2003, Italy has been affected by two epidemics of highly pathogenic avian influenza (HPAI) and by several outbreaks of low pathogenic avian influenza (LPAI). In 1999-2000 a severe HPAI epidemic affected the country, causing 413 outbreaks: a total of about 16 million birds died or were stamped out. From August 2000 to March 2001, a H7N1 LPAI strain infected 78 poultry farms. The last affected flock was stamped out on the 26th of March 2001. In October 2002, another LPAI virus of the H7N3 subtype emerged and infected a total of 388 poultry holdings. Eradication measures were based on stamping out or controlled marketing of slaughtered birds on infected farms and on the prohibition of restocking. Restriction measures on the movement of live poultry, vehicles and staff were also imposed. To supplement these disease control measures, two emergency vaccination programmes, based on the "DIVA" (Differentiating Infected from Vaccinated Animals) strategy were implemented. The two vaccination campaigns (2000-2002 and 2002-2003) both resulted in the eradication of infection. However, the first campaign appeared to be more successful that the second and possible explanations are discussed.

Effect of indapamide SR on microalbuminuria--the NESTOR study (Natrilix SR versus Enalapril Study in Type 2 diabetic hypertensives with micrOalbuminuRia)--rationale and protocol for the main trial

In type 2 diabetic hypertensive patients, microalbuminuria can be due to hypertension and/or diabetic nephropathy. Angiotensin-converting enzyme (ACE) inhibitors act preferentially on microalbuminuria due to diabetic nephropathy. The objective is to demonstrate the efficacy of a thiazide-like diuretic, indapamide sustained release (SR), at reducing microalbuminuria in hypertensive type 2 diabetic patients in comparison with an ACE inhibitor, enalapril. The study is an international multicentre, 12-month, randomized, double-blind, controlled, two parallel group study of type 2 diabetic patients with hypertension (140 mmHg < or = systolic blood pressure <180 mmHg and diastolic blood pressure <110 mmHg) and microalbuminuria. Intervention is after a 4-week placebo period, patients with microalbuminuria > or = 20 and < or = 200 microg/min are randomized to indapamide SR 1.5 mg or to enalapril 10 mg once a day for a one-year treatment period. An additional label treatment by amlodipine 5-10 mg (1st step) and atenolol 50-100 mg (2nd step) a day is permitted after 6 weeks of treatment based upon blood pressure response. The main outcome measures are microalbuminuria expressed as urinary albumin to creatinine ratio, albumin fractional clearance, and albumin excretion rate evaluated on overnight urine collections. Secondary criteria are supine and standing systolic, diastolic and mean blood pressure; and biological and clinical safety. This study will complete the knowledge of the efficacy of indapamide SR in hypertension and target organ damage and will provide valuable information on the management of type 2 diabetic hypertensives with microalbuminuria.

Secretory defects induced by immunosuppressive agents on human pancreatic beta-cells

Despite the considerable interest for islet and pancreas transplantation, remarkably little is known about the direct effects of immunosuppressive drugs on human beta-cell function. We measured different insulin secretory parameters and insulin gene expression of human islets cultured for 5 days in the presence of mycophenolate mofetil (MMF), cyclosporin A (CsA), tacrolimus (FK506) or a mixture of 3 cytokines. Basal insulin release after exposure to cytokines and FK506 was significantly higher than in control islets. Responsiveness to an acute glucose stimulus did not differ significantly between control and treated islets. However, absolute incremental insulin responses (delta-AUCs) of islets exposed to cytokines or FK506 were significantly higher compared to islets exposed to CsA or MMF, mainly because of the higher basal release. Indeed, maximal over basal release (stimulation index, SI) tended to be lower in islets exposed to FK506 than in control islets. Insulin gene expression was significantly reduced only in islets exposed to CsA. FK506 was, among those tested, the immunosuppressive drug that most profoundly altered the normal insulin secretory pattern of human beta-cells, whereas CsA was the only inhibiting insulin gene expression. Although the abnormalities induced by the immunosoppressive drugs utilized in this study were modest, these in vitro data are consistent with the reported in vivo diabetogenicity of CsA and FK506 and point to MMF as the ideal immunosuppressive agent from a pancreatic beta-cell point of view.

Autoantibody response to islet transplantation in type 1 diabetes

Islet allotransplantation into patients with autoimmune type 1 diabetes represents a reexposure to autoantigen. Here, measurement of antibodies to GAD and IA-2 autoantigens before and after islet transplantation in 36 patients (33 receiving islet plus kidney grafts with cyclosporin and steroid-based immunosuppression, and 3 receiving solitary islet transplants with mycophenolate but cyclosporin-free immunosuppression) demonstrated marked rises in GAD antibodies within 7 days posttransplantation in 5 patients (3 receiving islet after kidney transplants, and 2 receiving solitary islet transplants) and within 30 days in the third patient receiving solitary islet transplantation. GAD antibodies were of the IgG1 subclass, against major autoantigenic epitopes, and in cases of islet after kidney transplants, the responses were short-lived and not accompanied by HLA antibodies. Two of these patients had subsequent marked rises of IA-2 antibodies, and an additional patient had a marked rise in IgM-GAD antibodies 3 years after transplantation. Insulin independence was not achieved in patients with autoantibody elevations and was significantly less frequent in these patients. These data are consistent with a reactivation of autoimmunity that may be dependent on immunosuppression therapy and is associated with impaired graft function.

Cardiovascular outcomes after kidney-pancreas and kidney-alone transplantation

BACKGROUND

This study retrospectively assessed, with an intention-to-treat analysis, the effect of kidney-pancreas transplantation (KP) on survival and cardiovascular outcome in type 1 diabetic uremic patients.

METHODS

A total of 351 uremic type 1 diabetic patients were enrolled on a waiting list for KP: 130 underwent KP transplantation, 25 underwent kidney transplantation alone (KA), whereas 196 patients remained on dialysis (WL). The three populations had similar cardiovascular conditions. Actuarial survival rates and causes of death were recorded over a period of seven years. Finally, 23 KP and 13 KA patients underwent left radionuclide ventriculography, during a follow-up of four years.

RESULTS

In the entire group of 351 patients the seven-year survival rate was 77.4% for KP, 56.0% for KA and 39.6% for WL (KP vs. WL, P = 0.01). Cardiovascular death rate was 7.6% in KP, 20.0% in KA and 16.1% in WL (KP versus WL, P = 0.03; KP vs. KA, P = 0.16). In the subsample studied with radionuclide ventriculography, left ventricular ejection fraction improved in KP, but did not in KA, with significant differences between groups at two and four years. At four years only the KP patients presented normal values of diastolic parameters, including the peak filling rate, time-to-peak filling rate, and peak filling rate/peak ejection rate ratio. Glycated hemoglobin was negatively associated with the ejection fraction, peak filling rate and peak filling rate/peak ejection rate ratio, and positively associated with the time-to-peak filling rate.

CONCLUSIONS

Normalization of blood glucose metabolism and improvement of blood pressure control obtained with KP transplant is associated with positive effects on survival, cardiovascular death rate, and left ventricular function.

Triglycerides impair postischemic recovery in isolated hearts: roles of endothelin-1 and trimetazidine

There is growing evidence that hypertriglyceridemia exacerbates ischemic injury. We tested the hypothesis that triglycerides impair myocardial recovery from low-flow ischemia in an ex vivo model and that such an effect is related to endothelin-1. Hyperglycemic (glucose concentration = 12 mmol/l) and hyperinsulinemic (insulin concentration = 1.2 micromol/l) isolated rat hearts were perfused with Krebs-Henseleit buffer (PO(2) = 670 mmHg, pH 7.4, 37 degrees C) added with increasing triglycerides (0, 1,000, 2,000, and 4,000 mg/dl, n = 6-9 rats/group). Hearts were exposed to 60 min of low-flow ischemia (10% of basal coronary flow), followed by 30 min of reperfusion. We found that increasing triglycerides impaired both the diastolic (P < 0.005) and systolic (P < 0.02) recovery. The release of endothelin-1 during reperfusion increased linearly with triglyceride concentration (P = 0.0009). Elevated triglycerides also increased the release of nitrite and nitrate (NO(x)), the end products of nitric oxide, up to 6 micromol/min. Trimetazidine (1 micromol) further increased NO(x) release, blunted endothelin-1 release, and protected myocardial function during recovery. We conclude that high triglyceride levels impair myocardial recovery after low-flow ischemia in association with endothelin-1 release. The endothelium-mediated effect of triglycerides on both contractile recovery and endothelin-1 release is prevented by 1 microM trimetazidine.

Prediction of the long-term metabolic success of the pancreatic graft function

BACKGROUND

Strategies to prevent the return to the diabetic state for graft loss or failure or any other cause after pancreas transplantation require the identification of the subjects at risk. This study evaluated whether daily glucose, insulin, and c-peptide profiles and studies of insulin sensitivity and secretion after transplantation predict pancreatic graft failure.

METHODS

Fifty-three subjects with type 1 diabetes with end-stage renal failure who received a combined pancreas and kidney transplant underwent the following procedures 1 year after transplantation: 1-day metabolic profiles, sampling every 2 hours for plasma glucose, serum insulin, and c-peptide (n=51); an intravenous glucose tolerance test (IVGTT) to evaluate insulin secretion (n=48); and an euglycemic insulin clamp to evaluate insulin sensitivity (M value, n=14). The recipients were then followed up to 8 years (mean follow-up 4.8+/-0.3 years) to evaluate the return to the diabetic state.

RESULTS

Survival analysis showed that plasma glucose in the profiles and insulin secretion in IVGTT were strongly related to the risk of returning to the diabetic state. A cutoff value of mean daily plasma glucose >127 mg/dL, corresponding to the top quartile of the mean plasma glucose distribution in the profiles, predicted the return to the diabetic state within 4 years from transplantation with a 93% specificity and a 100% sensitivity. A cutoff value of insulin delta peak <32 microU/ml in the IVGTT predicted the return to the diabetic state within 4 years from transplantation with a 75% specificity and a 75% sensitivity. In contrast, the M value in the clamp was devoid of predictive value.

CONCLUSIONS

This study indicates that the mean 24-h plasma glucose 1 year after transplantation is the strongest predictor of the return to the diabetic state. The risk is related to defects in insulin secretion and not to insulin resistance. Metabolic profiles can be used to screen the subjects at risk to strictly monitor the graft function and to investigate early determinants of graft failure.

Long-term oral L-arginine administration improves peripheral and hepatic insulin sensitivity in type 2 diabetic patients

The aim of this study was to evaluate whether long-term administration of arginine acting through a normalization of NO/cyclic-guanosine-3' 5'-cyclic monophosphate (cGMP) pathway was able to ameliorate peripheral and hepatic insulin sensitivity in 12 lean type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

A double-blind study was performed for 3 months. In the first month, patients were treated with their usual diet. Then they were randomly allocated into to groups. In group 1, patients were treated with diet plus placebo (orally three times per day) for 2 months. In group 2 patients were treated for 1 month with diet plus placebo orally, three times per day) and then for 1 month with diet plus L-arginine (3 g three times per day). At the end of the first and the second month of therapy, patients underwent a euglycemic-hyperinsulinemic clamp combined with [6,6-2H2] glucose infusion. A total of 10 normal subjects underwent the same test as control subjects.

RESULTS

In group 1, no changes in basal cGMP levels, systolic blood pressure, forearm blood flow, glucose disposal, and endogenous glucose production were observed throughout. In group 2, L-arginine normalized basal cGMP levels and significantly increased forearm blood flow by 36% and glucose disposal during the clamp by 34% whereas it decreased systolic blood pressure and endogenous glucose production by 14 and 29%, respectively. However, compared with normal subjects, L-arginine treatment was not able to completely overcome the defect in glucose disposal.

CONCLUSIONS

L-Arginine treatment significantly improves but does not completely normalizc peripheral and hepatic insulin sensitivity in type 2 diabetic patients.

Combined liver and pancreatic islets transplantation in man using cyclosporin immunosuppression

We report a 1-year patient and graft survival after combined liver-pancreatic islet transplantation. The patient was affected by a pancreatic neuroendocrine carcinoma with extensive liver metastasis. Native pancreas and total liver removal was undertaken after a good response to chemotherapy, and the patient was still cancer-free 1 year later. Normal liver function and insulin independence was achieved, although islet response to glucose challenge remained delayed. Immunosuppression was maintained with cyclosporin monotherapy.

Effects of kidney-pancreas transplantation on atherosclerotic risk factors and endothelial function in patients with uremia and type 1 diabetes

Cardiovascular disease and the development of coronary artery disease play a pivotal role in increasing mortality in patients with type 1 diabetes. The aim of our study was to evaluate the effects of pancreas transplantation on atherosclerotic risk factors, endothelial-dependent dilation (EDD), and progression of intima media thickness (IMT) in patients with uremia and type 1 diabetes after kidney-alone (KA) or kidney-pancreas (KP) transplantation. A cross-sectional study comparing two groups of patients with type 1 diabetes was performed. Sixty patients underwent KP transplantation and 30 patients underwent KA transplantation. Age and cardiovascular risk profile were comparable in patients before transplantation. In all patients, atherosclerotic risks factors (lipid profile, fasting and post-methionine load plasma homocysteine, von Willebrand factor levels, D-dimer fragments, and fibrinogen) were assessed and Doppler echographic evaluation of IMT and endothelial function with flow-mediated and nitrate dilation of the brachial artery was performed. Twenty healthy subjects were chosen as controls (C) for EDD. Compared with patients undergoing KA transplantation, patients undergoing KP transplantation showed lower values for HbA1c (KP = 6.2 +/- 0.1% vs. KA = 8.4 +/- 0.5%; P < 0.01), fasting homocysteine (KP = 14.0 +/- 0.7 mcromol/l vs. KA = 19.0 +/- 2.0 micromol/l; P = 0.02), von Willebrand factor levels (KP = 157.9 +/- 8.6% vs. KA = 212.5 +/- 16.2%; P < 0.01), D-dimer fragments (KP = 0.29 +/- 0.02 microg/ml vs. KA = 0.73 +/- 0.11 microg/ml;P < 0.01), fibrinogen (KP = 363.0 +/- 11.1 mg/dl vs. KA = 397.6 +/- 19.4 mg/dl; NS), triglycerides (KP = 122.7 +/- 8.6 mg/dl vs. KA = 187.0 +/- 30.1 mg/dl; P = 0.01), and urinary albumin excretion rate (KP = 13.5 +/- 1.9 mg/24 h vs. KA = 57.3 +/- 26.3 mg/24 h; P < 0.01). Patients undergoing KP transplantation showed a normal EDD (KP = 6.21 +/- 2.42%, KA = 0.65 +/- 2.74%, C = 8.1 +/- 2.1%; P < 0.01), whereas no differences were observed in nitrate-dependent dilation. Moreover, IMT was lower in patients undergoing KP transplantation than in patients undergoing KA transplantation (KP = 0.74 +/- 0.03 mm vs. KA = 0.86 +/- 0.09 mm; P = 0.04). Our study showed that patients with type 1 diabetes have a lower atherosclerotic risk profile after KP transplantation than after KA transplantation. These differences are tightly correlated with metabolic control, fasting homocysteine levels, lower D-dimer fragments, and lower von Willebrand factor levels. Normal endothelial function and reduction of IMT was observed only in patients undergoing KP transplantation.

Metabolic effects of restoring partial beta-cell function after islet allotransplantation in type 1 diabetic patients

Successful intraportal islet transplantation normalizes glucose metabolism in diabetic humans. To date, full function is not routinely achieved after islet transplantation in humans, with most grafts being characterized by only partial function. Moreover, the duration of full function is variable and cannot be sufficiently predicted with available methods. In contrast, most grafts retain partial function for a long time. We hypothesized that partial function can restore normal protein and lipid metabolism in diabetic individuals. We studied 45 diabetic patients after islet transplantation. Labeled glucose and leucine were infused to assess whole-body glucose and protein turnover in 1) 6 type 1 diabetic patients with full function after intraportal islet transplantation (FF group; C-peptide > 0.6 nmol/l; daily insulin dosage 0.03 +/- 0.02 U x kg(-1) body wt x day(-1); fasting plasma glucose < 7.7 mmol/l; HbA1c < or = 6.5%), 2) 17 patients with partial function (PF group; C-peptide > 0.16 nmol/l; insulin dosage < 0.4 U x kg(-1) body wt x day(-1)), 3) 9 patients with no function (NF group; C-peptide < 0.16 nmol/l; insulin dosage > 0.4 U x kg(-1) body wt x day(-1)), and 4) 6 patients with chronic uveitis as control subjects (CU group). Hepatic albumin synthesis was assessed in an additional five PF and five healthy volunteers by means of a primed-continuous infusion of [3,3,3-2H3]leucine. The insulin requirement was 97% lower than pretransplant levels for the FF group and 57% lower than pretransplant levels for the PF group. In the basal state, the PF group had a plasma glucose concentration slightly higher than that of the FF (P = 0.249) and CU groups (P = 0.08), but was improved with respect to the NF group (P < 0.01). Plasma leucine (101.1 +/- 5.9 micromol/l) and branched-chain amino acids (337.6 +/- 16.6 micromol/l) were similar in the PF, FF, and CU groups, and significantly lower than in the NF group (P < 0.01). During insulin infusion, the metabolic clearance rate of glucose was defective in the NF group versus in the other groups (P < 0.01). Both the basal and insulin-stimulated proteolytic and proteosynthetic rates were comparable in the PF, FF, and CU groups, but significantly higher in the NF group (P = 0.05). In addition, the PF group had a normal hepatic albumin synthesis. Plasma free fatty acid concentrations in the PF and FF groups were similar to those of the CU group, but the NF group showed a reduced insulin-dependent suppression during the clamp. We concluded that the restoration of approximately 60% of endogenous insulin secretion is capable of normalizing the alterations of protein and lipid metabolism in type 1 diabetic kidney recipients, notwithstanding chronic immunosuppressive therapy. The results of the present study indicate that "success" of islet transplantation may be best defined by a number of metabolic criteria, not just glucose concentration/metabolism alone.

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.

Reversal of left ventricular diastolic dysfunction after kidney-pancreas transplantation in type 1 diabetic uremic patients

OBJECTIVE

Diastolic function is frequently impaired in diabetic patients. Our aim was to evaluate the effects of glycometabolic control achieved by pancreas transplantation on left ventricular function in uremic type 1 diabetic patients.

RESEARCH DESIGN AND METHODS

Left ventricular systolic and diastolic functions were evaluated using radionuclide ventriculography in 42 kidney-pancreas transplant patients and 26 kidney-alone recipients who had similar clinical characteristics before transplantation. Patients were grouped according to 6, 24, and 48 months of follow-up. Control subjects consisted of 20 type 1 diabetic patients.

RESULTS

The left ventricular ejection fraction was normal in all of the patients. However, kidney-pancreas transplant patients with 4 years of graft function had a higher ejection fraction (75.7 +/- 1.8%) than kidney-alone patients with 4 years of graft function (65.3 +/- 2.8%, P = 0.02) and type 1 diabetic patients (61.3 +/- 3.7%, P = 0.004). In patients with 4 years of graft function, normal diastolic parameters were evident in kidney-pancreas but not in kidney-alone or in type 1 diabetic patients (peak filling rate: 4.46 +/- 0.15 end diastolic volume (EDV)/s in kidney-pancreas patients vs. 2.73 +/- 0.24 EDV/s [P < 0.01] and 3.39 +/- 0.30 EDV/s [P < 0.01] in kidney-alone and type 1 diabetic patients, respectively; time-to-peak filling rate: 141.9 +/- 7.8 ms in kidney-alone patients vs. 209.4 +/- 13.5 ms in kidney-alone patients [P < 0.01]; peak filling rate/peak ejection rate ratio: 1.10 +/- 0.04 in kidney-pancreas patients vs. 0.81 +/- 0.08 in kidney-alone patients [P < 0.01]). A significant reduction in diastolic dysfunction rate was observed only in kidney-pancreas patients.

CONCLUSIONS

Kidney-pancreas transplantation results in complete insulin independence, a better glycometabolic pattern and blood pressure control, an improvement of left ventricular function, and a reversal of diastolic dysfunction.

Insulin-secreting pituitary GH3 cells: a potential beta-cell surrogate for diabetes cell therapy

In a companion article, we describe the engineering and characterization of pituitary GH3 cell clones stably transfected with a furin-cleavable human insulin cDNA (InsGH3 cells). This article describes the performance of InsGH3 (clones 1 and 7) cell grafts into streptozotocin (STZ)-induced diabetic nude mice. Subcutaneous implantation of 2 x 10(6) InsGH3 cells resulted in the progressive reversal of hyperglycemia and diabetic symptoms, even though the progressive growth of the transplanted cells (clone 7) eventually led to glycemic levels below the normal mouse range. Proinsulin transgene expression was maintained in harvested InsGH3 grafts that, conversely, lose the expression of the prolactin (PRL) gene. Elevated concentrations of circulating mature human insulin were detected in graft recipients, demonstrating that proinsulin processing by InsGH3 cells did occur in vivo. Histologic analysis showed that transplanted InsGH3 grew in forms of encapsulated tumors composed of cells with small cytoplasms weakly stained for the presence of insulin. Conversely, intense insulin immunoreactivity was detected in graft-draining venules. Compared to pancreatic betaTC3 cells, InsGH3 cells showed in vitro a higher rate of replication, an elevate resistance to apoptosis induced by serum deprivation and proinflammatory cytokines, and significantly higher antiapoptotic Bcl-2 protein levels. Moreover, InsGH3 cells were resistant to the streptozotocin toxicity that, in contrast, reduced betaTC3 cell viability to 50-60% of controls. In conclusion, proinsulin gene expression and mature insulin secretion persisted in transplanted InsGH3 cells that reversed hyperglycemia in vivo. InsGH3 cells might represent a potential beta-cell surrogate because they are more resistant than pancreatic beta cells to different apoptotic insults and might therefore be particularly suitable for encapsulation.

Patient survival and cardiovascular events after kidney-pancreas transplantation: comparison with kidney transplantation alone in uremic IDDM patients

In diabetic patients cardiovascular morbidity and mortality is still a major problem. Our aim was to study the effect of kidney-pancreas transplantation on survival, cardiovascular events, and causes of death in diabetic type 1 uremic patients. Three hundred and thirty-three uremic IDDM patients were enrolled in our waiting list for kidney-pancreas transplantation: 107 underwent kidney-pancreas transplantation (KP), 34 underwent kidney transplantation alone (KA), whereas 192 patients remained on dialysis (WL). Actuarial survival and causes of death were recorded over a period of 7 years. Seven-year survival rate was 75% for the KP group, 63% for the KA group, and 37% for the WL group (p = 0.001). Cardiovascular death rate was 9.8% in the KP group, 17.6% in the KA group, and 18.1% in the WL group (KP vs. WL, p = 0.05). Rate of acute myocardial infarction in the KP group was lower than in the KA group (2.4% vs. 17.6%, p = 0.005) as well as rate of acute pulmonary edema (0.8% vs. 23.5%, p = 0.0001) and rate of hypertensive patients at 1 (40.9% vs. 85.0%, p = 0.0001) and at 2 years (57.6% vs. 80%, p = 0.03). Kidney-pancreas transplant helped to obtain euglycemia with positive effects on survival and cardiovascular events.

Insights from a successful case of intrahepatic islet transplantation into a type 1 diabetic patient

We report a case of long-term (>4 yr) successful intrahepatic islet transplantation into a type 1 diabetic patient chronically immunosuppressed for a prior kidney graft. The exogenous insulin requirement decreased progressively after transplantation, and insulin treatment was withdrawn at 6 months. Glycosylated hemoglobin levels were in the normal range at 1 and 2 yr (5.3%) and increased slightly above the upper normal limit at 3 and 4 yr (6.3% and 6.4%). Fasting C peptide levels remained stable during the entire follow-up, but the proinsulin to insulin ratios increased dramatically at yr 3. Glycemic levels after an oral glucose tolerance test showed a diabetic profile at 1 yr, a normal profile at 2 yr, and an impaired glucose tolerance profile at 3 yr. Intravenous glucose tolerance test-induced first phase insulin release, present at 1 and 2 yr, disappeared at 3 yr. Diabetes-related autoantibodies (islet cell antibodies, glutamic acid decarboxylase antibodies, and tyrosine phosphatase-like protein antibodies) were undetectable before transplantation and remained so during the entire follow-up. The patient died of myocardial infarction 50 months after transplantation while she was still in good metabolic control (glycosylated hemoglobin, <6.8%) in the absence of exogenous insulin administration. The autoptic liver showed well granulated islets, richly vascularized and without evidence of lympho-mononuclear cell infiltration. The morphometrically extrapolated intrahepatic beta-cell mass was 99.9 mg. In conclusion, this successful islet graft showed a bell-shaped clinical effect, maximal at 2 yr after transplantation, followed by a slow progressive decline. The absence of allo- and autoreactivities against the transplanted islets points to a nonimmune-mediated beta-cell loss as the cause of graft functional deterioration.

Alterations in nitric oxide/cyclic-GMP pathway in nondiabetic siblings of patients with type 2 diabetes

In this study, we have compared resistance to insulin-mediated glucose disposal and plasma concentrations of nitric oxide (NO) and cyclic-GMP in healthy volunteers with (n = 35) or without (n = 27) at least one sibling and one parent with type 2 diabetes. The 62 volunteers were further divided into groups of those with normal glucose tolerance or impaired glucose tolerance. Insulin-mediated glucose disposal was quantified by determining the insulin sensitivity index (ISI) in response to a low-dose, constant infusion of insulin (25 mU/kg x h) and glucose (4 mg/kg x min) for 150 min. The mean (+/-SEM) ISI [(mL kg(-1) min(-1)/pmol/L) x 10(3)] was significantly greater in those without a family history (30.3 +/- 2.3) as compared with nondiabetic volunteers with a family history of type 2 diabetes, whether they had normal glucose tolerance (17.0 +/- 7.2) or impaired glucose tolerance (9.5 +/- 1.4). In addition, basal NO levels, evaluated by the measurement of its stable end products [i.e. nitrite and nitrate levels (NO2-/ NO3-)], were significantly higher, and cyclic-GMP levels, its effector messenger, were significantly lower in those with a family history, irrespective of their degree of glucose tolerance, when compared with healthy volunteers without a family history of type 2 diabetes. Furthermore, when the 62 volunteers were analyzed as one group, there was a negative correlation between ISI and NO2-/NO3- levels (r = -0.35; P < 0.005) and a positive correlation between ISI and cyclic-GMP levels (r = 0.30; P < 0.02). These results have shown that alterations of the NO/cyclic-GMP pathway seem to be an early event in nondiabetic individuals with a family history of type 2 diabetes and these changes are correlated with the degree of insulin resistance.

Three novel missense mutations in the glucokinase gene (G80S; E221K; G227C) in Italian subjects with maturity-onset diabetes of the young (MODY). Mutations in brief no. 162. Online

The maturity-onset diabetes of the young (MODY), an autosomal dominant form of non-insulin dependent diabetes mellitus (NIDDM), is caused by mutations in the glucokinase (GK, MODY 2) and in the hepatocyte nuclear factor 1a (MODY 3) and 4a (MODY 1) genes. We have screened the glucokinase gene by the polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) in fifteen subjects with clinical characteristics of MODY and one parent with NIDDM, impaired glucose tolerance or gestational diabetes. PCR products with abnormal mobility in DGGE were directly sequenced. We have identified four mutant alleles, three of them (G80S, E221K, G227C) are new missense mutations located in or near the region of the active site cleft of the enzyme. The mutations co-segregate with hyperglycemia in the families of the three probands, whose biochemical and clinical phenotype is similar to other individuals with MODY 2 mutations.

Persistence of anomalies in the growth hormone-releasing hormone-stimulated growth hormone response in diabetic-uremic patients after combined kidney-pancreas transplantation

Increased circulating growth hormone (GH) levels and aberrant response to different stimuli characterize both type 1 diabetes mellitus and chronic uremia and are associated with severe retinal, kidney and heart complications. Combined kidney and pancreas transplantation is a therapy that restores the endogenous, closed-loop, insulin secretion in diabetes and cure uremia. To evaluate if combined transplantation can restore a normal secretion and response of GH to growth hormone releasing hormone (GH-RH), we studied four groups of subjects: (1) seven type 1 diabetic patients with end-stage renal failure who had received pancreas and kidney transplantation (KPTx); (2) six diabetic uremic subjects, candidates for combined transplantation (IDDUP); (3) nine patients with chronic uveitis on immunosuppressive therapy comparable to pancreas recipients, six of whom treated only with prednisone (UVEST), while three (4) were treated with both prednisone and cyclosporin (UVESTCY). All subjects underwent a GH-RH test (50 microg intravenously, i.v., at 13:00 h). Serum insulin levels were significantly higher in IDDUP compared to UVEST (P=0.05) both at baseline and post GH-RH stimulus, while were similar to KPTx (P=0.2) and UVESTCY (P=0.7). In contrast, plasma free fatty acids were similar in all groups. In IDDUP baseline plasma glycerol was higher than in KPTx (P=0.04) and UVEST (P=0.02) and similar to UVESTCY (P=0.36); glycerol concentration did not change after GH-RH (P=0.08). Before and after GH-RH, serum GH levels tended to be higher in IDDUP (P=0.5) and KPTx (P=0.2) compared to UVEST and UVESTCY. Our results indicate that: 1) kidney-pancreas transplantation does not normalize the GH response to GH-RH; 2) GH abnormalities are not due either to the chronic immunosuppressive therapy or to the insulin effect on GH release; 3) GH abnormalities are probably secondary to functional and/or organic complications of the hypothalamus and/or pituitary as a sequela of diabetes mellitus.

Modulation of humoral islet autoimmunity by pancreas allotransplantation influences allograft outcome in patients with type 1 diabetes

Pancreas transplantation in patients with type 1 diabetes presents allogeneic beta-cell autoantigens to the immune system long after the initial beta-cell destruction that leads to diabetes has occurred. The aims of this study were to determine whether re-exposure to beta-cell autoantigen through transplantation affect the humoral autoimmune response and whether its modulation correlates with graft outcome. Antibodies to the major autoantigens GAD (GADA) and protein tyrosine phosphatase IA-2 (IA-2A) were measured before and after transplantation in patients with type 1 diabetes who received pancreas and kidney allografts. In the 110 cases studied, pancreas graft survival was not significantly associated with the presence of GADA or IA-2A before transplantation. In the 75 patients with sequential follow-up samples up to 11.2 years after transplantation, autoantibodies were persistently undetectable in 44 cases (59%) and remained at stable detectable levels in 13 cases (17%). Substantial changes in antibody levels were found in 18 cases (24%), of which 13 cases (17%) had declining levels and 5 cases (7%) had marked increments after transplantation. Rising GADA and IA-2A levels in these five patients were predominantly of the IgG1 subclass, with progressive spreading of epitope reactivity. Pancreas graft function was lost 0.7-2.3 years after rising autoantibody levels in four of these five patients, and a significantly lower pancreas graft survival was found in patients with major rises in either GADA or IA-2A levels (P < 0.0001 vs. the remainder) and in patients having persistently high levels of IA-2A (P = 0.002 vs. stable antibody-negative patients). Kidney graft survival was not associated with islet autoantibody status. In conclusion, a minority of patients receiving pancreas allografts under generalized immunosuppression show a stimulation of islet autoantibody reactivity characteristic of that found in preclinical type 1 diabetes, which is almost invariably followed by graft function failure and resumption of insulin therapy.

Postabsorptive muscle protein metabolism in type 1 diabetic patients after pancreas transplantation

Insulin was shown to induce protein anabolism in vivo mainly by inhibiting proteolysis. Heterotopic pancreas transplantation in type 1 diabetes mellitus is characterized by peripheral hyperinsulinemia due to systemic rather than portal insulin delivery. Therefore, we studied the postabsorptive muscle protein metabolism in type 1 diabetic patients with or without pancreas transplantation. The forearm balance technique was performed in 9 type 1 diabetic patients on exogenous insulin treatment, in 4 type 1 diabetic patients following successful pancreas transplantation and in 6 healthy volunteers. Labelled leucine and phenylalanine were infused to quantify whole-body and muscle protein synthesis, respectively. In the postabsorptive state, whole-body protein synthesis (leucine kinetics) was similar in pancreas-transplanted patients and controls. In contrast, muscle protein synthesis tended to be less negative in pancreas-transplanted patients with respect to type 1 diabetic patients and healthy volunteers. The present data suggest that recipients with peripheral insulin delivery and chronic hyperinsulinemia are characterized by a preferential stimulation of protein synthesis in muscle rather than in the splanchnic district. When insulin was infused acutely, while maintaining euglycemia, the whole-body and muscle protein synthesis rates were approximately halved in type 1 diabetic patients with and without pancreas transplantation. We conclude that pancreas transplantation is able to normalize basal and insulin-stimulated protein metabolism. Chronic hyperinsulinemia counteract steroid-induced protein degradation by means of a mild, but persistent stimulation of muscle protein synthesis.

Effects of endothelin-1 and nitric oxide on glucokinase activity in isolated rat hepatocytes

To test the hypothesis that endothelin-1 (ET-1) and nitric oxide (NO) influence glucokinase (GK) activity in an opposite manner, we evaluated the effects of ET-1, L-NAME, an inhibitor of NO synthase, and L-arginine, a substrate for NO synthase, on GK activity and glycogen content in isolated rat hepatocytes. Moreover, to understand the receptor involved in the process, the effects of BQ 788, a specific antagonist of ETB receptor, and PD 142893, an antagonist of ETA-ETB receptors, were also evaluated. GK activity, cyclic guanosine monophosphate (cGMP), and glycogen intracellular content were measured on isolated hepatocytes, while glucose levels and NO as NO2-/NO3- were determined in the medium. High ET-1 levels induced a 20% decrease of NO2-/NO3- levels and cGMP intracellular content, followed by a 49% reduction of GK activity and a 15% decrease of glycogen. In parallel, a 10% increase of glucose in the medium was observed. In the presence of L-NAME, GK activity and glycogen levels showed analogous decrements as observed with ET-1. Also in this case, a significant decrease of the intracellular content of cGMP was observed. No synergistic effects of ET-1 and L-NAME were observed. L-Arginine was able to counteract the inhibitory effect of ET-1 on cGMP and GK activity. Glycogen content was slightly but not significantly reduced, and under those conditions, a significant decrease of glucose in the medium was observed. When hepatocytes were incubated with ET-1 plus BQ 788 or ET-1 plus PD 142893, GK activity was unchanged. Interestingly, no changes were observed in NO2-/NO3- levels and the intracellular content of cGMP was not modified when the antagonists of ET-1 receptors were added to the medium. In conclusion, the present study shows that the NO pathway seems to be an important regulator of GK activity and glycogen content through cGMP activity. In addition, ET-1 seems to be not active per se, but its activity seems mediated by a simultaneous decrease of NO levels.

Endothelial and metabolic characteristics of patients with angina and angiographically normal coronary arteries: comparison with subjects with insulin resistance syndrome and normal controls

OBJECTIVES

This study was performed to characterize the endothelial and metabolic alterations of patients with angina and angiographically normal coronary arteries ("cardiac" syndrome X [CSX]) compared with subjects with insulin resistance syndrome ("metabolic" syndrome X [MSX]) and normal controls.

BACKGROUND

Previous studies have found high endothelin-1 levels, impaired endothelium-dependent vasodilation and insulin resistance in patients with angina pectoris and angiographically normal coronary arteries. On the other hand, subjects with insulin resistance syndrome have shown high endothelin-1 levels.

METHODS

Thirty-five subjects were studied: 13 patients with angina pectoris and angiographically normal coronary arteries (CSX group); 9 subjects with insulin resistance syndrome (MSX group) and 13 normal controls. All subjects received an acute intravenous bolus of insulin (0.1 U/kg) combined with a euglycemic clamp and forearm indirect calorimetry. Endothelin-1 levels, nitrite/nitrate (NOx) levels, end products of nitric oxide metabolism, glucose infusion rates (index of insulin sensitivity) and their incremental areas (deltaAUCs [area under curves]) were measured during this period.

RESULTS

Basal endothelin-1 levels were higher in CSX and MSX groups than in normal controls (8.19 +/- 0.46 and 6.97 +/- 0.88 vs. 3.67 +/- 0.99 pg/ml; p < 0.01), while basal NOx levels were significantly higher in MSX group than in CSX and normal controls (36.5 +/- 4.0 vs. 24.2 +/- 3.3 and 26.8 +/- 3.2 mol/liter, p < 0.05). After insulin administration, the deltaAUCs of NOx (p < 0.05) were lower in CSX group than in MSX and normal controls, and the deltaAUCs of endothelin-1 were lower in group CSX than in normal controls. Glucose infusion rate was significantly lower in CSX and MSx groups than in normal controls (p < 0.01), suggesting that in both CSX and MSX groups insulin resistance is present. A positive correlation was found between the deltaAUCs of nitric oxide and the AUCs of glucose infusion rate.

CONCLUSIONS

Blunted nitric oxide and endothelin responsiveness to intravenously infused insulin is a typical feature of patients with angina pectoris and angiographically normal coronary arteries and may contribute to the microvascular dysfunction observed in these subjects.

Mechanisms of coordination of Ca2+ signals in pancreatic islet cells

Within pancreatic islet cells, rhythmic changes in the cytosolic Ca2+ concentration have been reported to occur in response to stimulatory glucose concentrations and to be synchronous with pulsatile release of insulin. We explored the possible mechanisms responsible for Ca2+ signal propagation within islet cells, with particular regard to gap junction communication, the pathway widely credited with being responsible for coordination of the secretory activity. Using fura-2 imaging, we found that multiple mechanisms control Ca2+ signaling in pancreatic islet cells. Gap junction blockade by 18 alpha-glycyrrhetinic acid greatly restricted the propagation of Ca2+ waves induced by mechanical stimulation of cells but affected neither Ca2+ signals nor insulin secretion elicited by glucose elevation. The source of Ca2+ elevation was also different under the two experimental conditions, the first being sustained by release from inner stores and the second by nifedipine-sensitive Ca2+ influx. Furthermore, glucose-induced Ca2+ waves were able to propagate across cell-free clefts, indicating that diffusible factors can control Ca2+ signal coordination. Our results provide evidence that multiple mechanisms of Ca2+ signaling operate in beta-cells and that gap junctions are not required for intercellular Ca2+ wave propagation or insulin secretion in response to glucose.

Effects of cryopreservation on in vitro and in vivo long-term function of human islets

BACKGROUND

The possibility of performing transplantation several days after explant seems to be a peculiarity of islet grafts, and the opportunity to cryopreserve human islets may permit an indefinite period for modulating the recipient immune system. The aim of the present study was the evaluation of in vitro and in vivo functional properties of cryopreserved human islets.

METHODS

We used six consecutive human islet preparations not suitable for an immediate transplantation in diabetic patients because the limited islet mass separated. The in vitro function of cryo and fresh islets was studied by determination of insulin and glucagon secretion in response to such classical stimuli as glucose (16.7 mM), glucose (16.7 mM) + 3-isobutyl-1-methylxanthine (0.1 mM), arginine (10 mM), and tolbutamide (100 microM). In vivo islet function was assessed through intravenous glucose tolerance tests performed at 15, 30, 60, and 90 days after transplantation of 1000 hand-picked fresh or cryopreserved islets in nude mice.

RESULTS

Basal secretion of true insulin was significantly higher in cryopreserved islets than in fresh ones. The response of cryopreserved islets to arginine and glucose + isobutyl-1-methylxanthine seemed partially impaired. Proinsulin-like molecule secretion seemed higher in cryopreserved than in fresh islets in response to all secretagogues used, and the difference was statistically significant for arginine. The capacity of human cryopreserved islets to maintain a correct metabolic control in diabetic nude mice was progressively lost in 3 months.

CONCLUSIONS

These findings showed that cryopreservation affects the function of isolated human islets, maintaining in vivo function for a limited period of time.

Intramyocellular triglyceride content is a determinant of in vivo insulin resistance in humans: a 1H-13C nuclear magnetic resonance spectroscopy assessment in offspring of type 2 diabetic parents

Insulin resistance is the best prediction factor for the clinical onset of type 2 diabetes. It was suggested that intramuscular triglyceride store may be a primary pathogenic factor for its development. To test this hypothesis, 14 young lean offspring of type 2 diabetic parents, a model of in vivo insulin resistance with increased risk to develop diabetes, and 14 healthy subjects matched for anthropomorphic parameters and life habits were studied with 1) euglycemic-hyperinsulinemic clamp to assess whole body insulin sensitivity, 2) localized 1H nuclear magnetic resonance (NMR) spectroscopy of the soleus (higher content of fiber type I, insulin sensitive) and tibialis anterior (higher content of fiber type IIb, less insulin sensitive) muscles to assess intramyocellular triglyceride content, 3) 13C NMR of the calf subcutaneous adipose tissue to assess composition in saturated/unsaturated carbons of triglyceride fatty acid chains, and 4) dual X-ray energy absorption to assess body composition. Offspring of diabetic parents, notwithstanding normal fat content and distribution, were characterized by insulin resistance and increased intramyocellular triglyceride content in the soleus (P < 0.01) but not in the tibialis anterior (P = 0.19), but showed a normal content of saturated/unsaturated carbons in the fatty acid chain of subcutaneous adipocytes. Stepwise regression analysis selected intramyocellular triglyceride soleus content and plasma free fatty acid levels as the main predictors of whole body insulin sensitivity. In conclusion, 1H and 13C NMR spectroscopy revealed intramyocellular abnormalities of lipid metabolism associated with whole body insulin resistance in subjects at high risk of developing diabetes, and might be useful tools for noninvasively monitoring these alterations in diabetes and prediabetic states.