Altered alanine plasma levels despite normalized hepatic alanine extraction in the long-term course after liver transplantation

BACKGROUND: The amino acid (AA) metabolism in cirrhosis is deranged, reflected by an altered plasma AA profile. Alanine is a unique AA with predominant production by muscle and the highest hepatic extraction rate. METHODS: We studied circulating levels and hepatic alanine extraction in 52 patients with advanced cirrhosis, 16 stable patients more than 6 months after orthotopic liver transplant (OLT), and 50 controls. In addition, hepatic hemodynamics (portal pressure, hepatic blood flow, and splanchnic percent indocyanine green extraction) and parameters of hepatic metabolism (splanchnic oxygen uptake and splanchnic glucose production) were assessed. RESULTS: Circulating alanine levels decreased independently of the clinical stage in cirrhosis (262+/-15 micromol/L vs. 330+/-14 micromol/L in controls, P<0.001) and decreased even further after OLT (209+/-10 micromol/L, P<0.001). Hepatic alanine extraction decreased dependently on the clinical stage in cirrhosis (59+/-7 micromol/min) and was normalized after OLT (100+/-10 micromol/min, P<0.001), indicating that decreased plasma alanine levels in OLT patients are the result of changes in extrahepatic metabolism. Hepatic alanine extraction correlated with splanchnic oxygen uptake (r=0.64, P<0.001) and hepatic glucose production (r=0.65, P<0.001). CONCLUSIONS: These results demonstrate that significant alterations in muscular AA metabolism persist even in the clinically stable long-term course after OLT when the hepatic AA metabolism is normalized.     

Insulin secretion and insulin sensitivity in relation to glucose tolerance: lessons from the Botnia Study

Recently, a new stage in glucose tolerance, impaired fasting glucose (IFG) (fasting plasma glucose level of 6.1-6.9 mmol/l), was introduced in addition to impaired glucose tolerance (IGT) (2-h glucose level of 7.8-11.0 mmol/l). It is not clear whether IFG and IGT differ with respect to insulin secretion or sensitivity. To address this question, we estimated insulin secretion (by measuring both insulin levels and the ratio of insulin-to-glucose levels in 30-min intervals) and insulin sensitivity (by using the homeostasis model assessment [HOMA] index) from an oral glucose tolerance test (OGTT) in 5,396 individuals from the Botnia Study who had varying degrees of glucose tolerance. There was poor concordance between IFG and IGT: only 36% (303 of 840) of the subjects with IFG had IGT, whereas 62% (493 of 796) of the subjects with IGT did not have IFG. Compared with subjects with normal glucose tolerance (NGT), subjects with IFG were more insulin resistant (HOMA-insulin resistance [IR] values 2.64 +/- 0.08 vs. 1.73 +/- 0.03, P < 0.0005), had greater insulin responses during an OGTT (P = 0.0001), had higher waist-to-hip ratios (P < 0.005), had higher triglyceride and total cholesterol concentrations (P < 0.0005), and had lower HDL cholesterol concentrations (P = 0.0001). Compared with subjects with IFG, subjects with IGT had a lower incremental 30-min insulin-to-glucose area during an OGTT (13.8 +/- 1.7 vs. 21.7 +/- 1.7, P = 0.0008). Compared with subjects with IGT, subjects with mild diabetes (fasting plasma glucose levels <7.8 mmol/l) showed markedly impaired insulin secretion that could no longer compensate for IR and elevated glucose levels. A progressive decline in insulin sensitivity was observed when moving from NGT to IGT and to subjects with diabetes (P < 0.05 for trend), whereas insulin secretion followed an inverted U-shaped form. We conclude that IFG is characterized by basal IR and other features of the metabolic syndrome, whereas subjects with IGT have impaired insulin secretion in relation to glucose concentrations. An absolute decompensation of beta-cell function characterizes the transition from IGT to mild diabetes.     

Plasma free Fatty Acid uptake and oxidation are already diminished in subjects at high risk for developing type 2 diabetes.

The objective of this study was to investigate to what extent disturbances in fatty acid metabolism found in type 2 diabetes are already present in subjects at high risk for developing diabetes (i.e., impaired glucose tolerance [IGT]). Components of fatty acid metabolism were measured in male subjects with IGT during postabsorptive conditions and during 60 min of exercise (50% VO(2max)) with the use of the stable isotope tracer [U-(13)C]palmitate in combination with indirect calorimetry, and those values were compared with previously published findings in male type 2 diabetic and male obese subjects. No differences were found between groups in energy expenditure and in total fat and carbohydrate oxidation. Rate of appearance and rate of disappearance of plasma free fatty acid (FFA) were lower in subjects with IGT and type 2 diabetes compared with obese subjects (P < 0.05). Plasma FFA oxidation was lower in subjects with IGT and type 2 diabetes compared with obese subjects at rest and tended to be lower during exercise (rest: 3.7 +/- 0.3, 4.4 +/- 0.6, and 6.9 +/- 1.0 micromol. kg fat-free mass [FFM](-1). min(-1), P < 0.01; exercise: 15.0 +/- 1.7, 14.1 +/- 1.9, and 19.6 +/- 1.5 micromol. kg FFM(-1). min(-1) for IGT, type 2 diabetic, and obese subjects, respectively, P = 0.07). Triglyceride-derived fatty acid oxidation, however, was elevated in subjects with IGT and type 2 diabetes during exercise (3.6 +/- 1.4, 1.4 +/- 1.4, and -4.0 +/- 2.0 micromol. kg FFM(-1). min(-1) for IGT, type 2 diabetic, and obese subjects, respectively; P < 0.05). These data demonstrate that male subjects with a prediabetic condition (IGT) have the same defects in fatty acid utilization as subjects with type 2 diabetes, suggesting that these disturbances may play an important role in the progression from IGT to type 2 diabetes.     

Differences in insulin resistance in nondiabetic subjects with isolated impaired glucose tolerance or isolated impaired fasting glucose

Both impaired glucose tolerance (IGT) (as defined by the 1985 World Health Organization criteria) and impaired fasting glucose (IFG) (as defined by the 1997 American Diabetes Association criteria) represent intermediate metabolic states between normal and diabetic glucose homeostasis. Cardiovascular disease may be related to postglucose load rather than fasting glycemia, i.e., IGT rather than IFG. We hypothesized that subjects with IGT may be more insulin resistant and have higher levels of common cardiovascular risk factors than those with isolated IFG. In the Insulin Resistance Atherosclerosis Study (IRAS), we studied S(i) and first-phase insulin secretion (acute insulin response [AIR]), as derived from a frequently sampled intravenous glucose tolerance test, as well as common cardiovascular risk factors in four different glucose tolerance categories (NFG/NGT [n = 654], NFG/IGT [n = 255], IFG/NGT [n = 59], and IFG/IGT [n = 102]) among nondiabetic subjects. Subjects with isolated postchallenge hyperglycemia (NFG/IGT) had lower S(i) (means +/- SE: 2.10 +/- 0.04 vs. 2.59 +/- 0.13 x 10(-4) min(-1). microU(-1). ml(-1); P = 0.005), lower proinsulin levels (34.4 +/- 1.8 vs. 42.0 +/- 4.5 pmol/l; P = 0.03), higher AIR (273.1 +/- 18.1 vs. 215.9 +/- 30.0 pmol/l; P = 0.04), higher C-reactive protein (2.49 +/- 0.3 vs. 1.49 +/- 0.5 mg/l; P = 0.0015), and higher triglyceride levels (137.7 +/- 5.5 vs. 108.4 +/- 8.9 mg/dl; P = 0.0025) than subjects with isolated fasting hyperglycemia (IFG/NGT). The relation of insulin resistance to glucose tolerance category was consistently seen in women and men and across the three ethnic groups of the IRAS (non-Hispanic whites, African Americans, and Hispanics). Nondiabetic individuals with isolated postchallenge hyperglycemia (IGT) are more insulin resistant than individuals with isolated fasting hyperglycemia (IFG). The risk factor pattern (including increased insulin resistance) seen in isolated IGT identifies a subgroup of nondiabetic individuals who are likely to benefit from early intervention.     

Type I diabetes manifested solely by 2-h oral glucose tolerance test criteria

The clinical presentation of type 1 diabetes usually involves symptoms such as polyuria and polydipsia. However, investigators in the Diabetes Prevention Trial of Type 1 Diabetes (DPT-1) have detected a group of subjects with type 1 diabetes who have a different phenotype. These subjects are asymptomatic, have normal (<6.1 mmol/l) (group A) or impaired (6.1- <7.0 mmol/l) (group B) fasting glucose, but have 2-h glucose values >11.1 mmol/l on their oral glucose tolerance tests (OGTT). Of the 585 OGTTs performed on islet cell antibody (ICA)-positive relatives with insulin autoantibodies (IAA) or low first-phase insulin response (FPIR), normal glucose tolerance (NGT) was found in 427 subjects; impaired glucose tolerance (IGT) was found in 87 subjects, and diabetes was found by 2-h OGTT criteria alone in 61 subjects. Despite marked differences in 2-h glucose values (NGT 5.8 +/- 1.1 mmol/l, IGT 8.9 +/- 0.9 mmol/l, and group A 13.5 +/- 2.5 mmol/l), there were no significant differences in fasting glucose values among NGT (4.8 +/- 0.5 mmol/l), IGT (5.03 +/- 0.5 mmol/l), and group A (4.99 +/- 0.7 mmol/l) categories. Mean FPIR was higher in subjects with NGT compared with subjects with IGT and subjects diagnosed by 2-h OGTT criteria alone. However, the correlation between FPIR and 2-h glucose value was low (r2 = 0.114). Multivariate analysis demonstrated that additional independent variables provide smaller contributions to the 2-h glucose value. In conclusion, there are asymptomatic type 1 diabetic subjects whose diabetes was diagnosed by the 2-h criteria on OGTT alone. Despite the importance of beta-cell dysfunction in the pathogenesis of type I diabetes, factors other than impaired FPIR must also contribute to postprandial glucose tolerance in these subjects.     

Major influence of liver function itself but not of immunosuppression determines glucose tolerance after living-donor liver transplantation.

Controversial data exists concerning the impact of immunosuppressive therapy on the development of post-transplantation diabetes mellitus (PTDM). Therefore, we investigated glucose metabolism in healthy donors and in recipients of living-donor liver transplants (LD-LTX, n=18) without pre-existing diabetes mellitus before, on day 10, month 6, and month 12 after intervention. The computer-assisted analysis of glucose, insulin, and C-peptide profiles obtained from frequently sampled intravenous glucose tolerance tests allows to achieve an integrated view of factors controlling glucose tolerance, i.e., insulin sensitivity (SI), first and second phase insulin secretion (phi1 and phi2). SI of donors declined by day 10 after operation (SI 2.65 +/- 0.41 vs. 4.90 +/- 0.50 10(-4) minute(-1) microU ml(-1), P < 0.01) but returned to values as before after 6 months. Phi1 did not change. Phi(2), however, significantly increased by day 10 (8.57 +/- 0.82 10(9) minute(-1) to 13.77 +/- 1.53 10(9) minute(-1), P < 0.01) but was in the same range as before after 6 months. In parallel to donors SI of recipients progressively increased after LD-LTX. Phi1 did not alter in recipients. Phi2 continuously decreased and was not different from donors by month 12. The extent of liver injury assessed by liver enzyme concentrations and liver function represented by cholinesterase activity, albumin, and INR were closely related with changes of SI in donors and recipients during the first year after intervention. In conclusion, the extent of liver damage plays a predominant role in regulating glucose tolerance. No impact of immunosuppressive therapy on SI, phi1 and phi2 was detected.     

Liver transplantation improves cirrhosis-associated impaired oral glucose tolerance

BACKGROUND: Thirty-five percent to 80% of cirrhotic patients have impaired glucose tolerance (IGT) or diabetes mellitus (DM). Diabetic cirrhotics have higher morbidity and mortality than nondiabetics. Therefore, it would be worthwhile to determine whether liver transplantation improves glucose homeostasis in these patients. METHOD: A total of 26 patients awaiting liver transplantation were evaluated for impaired glucose homeostasis by fasting blood glucose and/or oral glucose tolerance tests (OGTT). Five patients underwent transplant surgery within 1 year of OGTT and had a repeat OGTT 3-6 months after transplantation. RESULTS: Sixty-five percent (17/26) of the patients had abnormal glucose homeostasis. Twenty-three percent (6/26) met American Diabetes Association criteria for DM, and another 42.3% (11/26) had IGT. All patients had normal HbA1C levels. After transplantation, the 2-hr blood glucose improved in four patients and the mean 2-hr glucose level was reduced (204 +/- 94 vs. 132 +/- 53 mg/dl [mean +/- SD, P=0.051]). CONCLUSION: Liver transplantation can reverse cirrhosis-associated impaired glucose tolerance.     

Beta-cell function is a major contributor to oral glucose tolerance in high-risk relatives of four ethnic groups in the U.S

First-degree relatives of individuals with type 2 diabetes are at increased risk of developing hyperglycemia. To examine the prevalence and pathogenesis of abnormal glucose homeostasis in these subjects, 531 first-degree relatives with no known history of diabetes (aged 44.1 +/- 0.7 years; BMI 29.0 +/- 0.3 kg/m(2)) underwent an oral glucose tolerance test (OGTT). Newly identified diabetes was found in 19% (n = 100), and impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) was found in 36% (n = 191). Thus, only 45% (n = 240) had normal glucose tolerance (NGT). The homeostasis model assessment of insulin resistance (HOMA-IR) was used to estimate insulin sensitivity; beta-cell function was quantified as the ratio of the incremental insulin to glucose responses over the first 30 min during the OGTT (DeltaI(30)/DeltaG(30)). This latter measure was also adjusted for insulin sensitivity as it modulates beta-cell function ([DeltaI(30)/DeltaG(30)]/HOMA-IR). Decreasing glucose tolerance was associated with increasing insulin resistance (HOMA: NGT 12.01 +/- 0.54 pmol/mmol; IFG/IGT 16.14 +/- 0.84; diabetes 26.99 +/- 2.62; P < 0.001) and decreasing beta-cell function (DeltaI(30)/DeltaG(30): NGT 157.7 +/- 9.7 pmol/mmol; IFG/IGT 100.4 +/- 5.4; diabetes 57.5 +/- 7.3; P < 0.001). Decreasing beta-cell function was also identified when adjusting this measure for insulin sensitivity ([DeltaI(30)/DeltaG(30)]/HOMA-IR). In all four ethnic groups (African-American, n = 55; Asian-American, n = 66; Caucasian, n = 217; Hispanic-American, n = 193), IFG/IGT and diabetic subjects exhibited progressively increasing insulin resistance and decreasing beta-cell function. The relationships of insulin sensitivity and beta-cell function to glucose disposal, as measured by the incremental glucose area under the curve (AUCg), were examined in the whole cohort. Insulin sensitivity and AUCg were linearly related so that insulin resistance was associated with poorer glucose disposal (r(2) = 0.084, P < 0.001). In contrast, there was a strong inverse curvilinear relationship between beta-cell function and AUCg such that poorer insulin release was associated with poorer glucose disposal (log[DeltaI(30)/DeltaG(30)]: r(2) = 0.29, P < 0.001; log[(DeltaI(30)/DeltaG(30))/HOMA-IR]: r(2) = 0.45, P < 0.001). Thus, abnormal glucose metabolism is common in first-degree relatives of subjects with type 2 diabetes. Both insulin resistance and impaired beta-cell function are associated with impaired glucose metabolism in all ethnic groups, with beta-cell function seeming to be more important in determining glucose disposal.     

Endoneurial capillary abnormalities presage deterioration of glucose tolerance and accompany peripheral neuropathy in man

To explore whether microangiopathy is associated with disturbed glucose tolerance and peripheral neuropathy, we assessed endoneurial capillary morphology in sural nerve biopsies from men with diabetes, impaired glucose tolerance (IGT), and normal glucose tolerance (NGT). Baseline morphology was related to glucose tolerance and neuropathy at baseline and at follow-up 6 years later. Capillary density (in number per millimeters squared) at baseline was higher in subjects with diabetes (n = 10) compared with those with NGT (n = 5) at follow-up (median [interquartile range]) (86.0 [24.3] vs. 54.9 [17.1]; P = 0.0200) and in those progressing from IGT to diabetes (n = 4) compared with those with persistent IGT (n = 4) (86.7 [25.2] vs. 54.1 [14.6]; P = 0.0433). The capillary luminal area (in micrometers squared) was lower in subjects with NGT progressing to IGT (n = 2) or subjects with IGT progressing to diabetes (n = 3) compared with subjects with constant NGT (n = 6) or constant IGT (n = 4) (11.9 [2.4] vs. 20.8 [7.8]; P = 0.0201). The capillary basement membrane area (in micrometers squared) was increased in patients with peripheral neuropathy (n = 10) compared with those without (n = 7) (114.6 [68.8] vs. 75.3 [28.7]; P = 0.0084). In conclusion, increased capillary density was associated with current or future diabetes, decreased capillary luminal area with future deterioration in glucose tolerance, and increased basement membrane area with peripheral neuropathy.     

Efficacy of lamivudine therapy for advanced liver disease in patients with precore mutant hepatitis B virus infection awaiting liver transplantation

BACKGROUND: Orthotopic liver transplantation (OLT) for end-stage liver disease resulting from hepatitis B virus (HBV) infection is associated with a high rate of recurrence and reduced survival. Lamivudine is effective in inhibiting HBV replication in patients with chronic hepatitis. This study evaluated the impact of lamivudine on viral suppression, liver function, and disease severity in patients awaiting OLT with HBV e-minus strain infection. METHODS: Twenty-five patients received lamivudine (100 mg per day) from the day of listing for OLT. All patients were positive for serum HBV-DNA by polymerase chain reaction and all had a Child-Pugh score of 7 or higher. RESULTS: Patients were followed for 12+/-9 months (mean +/- SD). Eleven underwent OLT within 13 months of treatment initiation, one died after 10 months, and one dropped out after 3 months. After 3, 6, and 9 months, HBV-DNA by polymerase chain reaction was undetectable in 14 of 25, 14 of 20, and 13 of 15 patients, respectively. Two patients developed lamivudine resistance after 9 and 18 months of treatment, respectively, without liver decompensation. Comparing baseline to last visit data, a significant improvement in prothrombin activity (43+/-15% vs. 52+/-19%; P=0.0014), serum bilirubin (3.4+/-1.9 vs. 2.5+/-2.2 mg/dL; P=0.0007), serum albumin (3.3+/-0.3 vs. 3.6+/-0.5 g/dL; P=0.0278), presence of ascites (15/25 vs. 7/25; P=0.0047), and Child-Pugh score (9 vs. 8; P=0.0003) was observed. Because of liver function improvement, four patients were placed on low priority status for OLT (United Network of Organ Sharing 3) and 9 on inactive status (United Network of Organ Sharing 7). The overall probability of survival at 6 and 12 months was 100% and 90.9%, respectively. CONCLUSIONS: Lamivudine has an important role in patients with end-stage liver disease caused by HBV precore mutant strain. Not only does HBV-DNA suppression allow patients to be eligible for OLT, but the improvement of the patients' clinical status may delay the need for OLT in an era of organ shortage.     

Fenoldopam and gastric tonometry during orthotopic liver transplantation

The aim of this study was to evaluate the effects of continuous infusion of fenoldopam on splanchnic perfusion in orthotopic liver transplant (OLT) recipients. PATIENTS AND METHODS: We enrolled 40 patients of mean age 57+/-16 years who underwent (OLT). They were randomly divided into two double blinded groups; continuous fenoldopam (0.06 mcg/kg per minute) or placebo infusion. Hemodynamics, gastric tonometry, urine output, renal function parameters, and diuretics use were collected during selected phases of the surgery and postoperatively every 12 hours for 72 hours in the intensive care unit. RESULTS: No significant differences were observed between the two groups concerning hemodynamics, though in the fenoldopam group we observed increased splanchnic perfusion during the whole study period but particularly after arterial unclamping (pHi 7,31+/-0.04 vs 7.28+/-0.05; P < .05) and at 48 hours after surgery (pHi 7.49+/-0.15 vs 7.39+/-0.15; P < .05). Creatinine and blood urea nitrogen values were slightly higher in the placebo group, but this data did not reach statistical significance, while higher doses of furosemide were administered to the placebo group to maintain a urinary output over 200 mL/hour during the whole study. DISCUSSION: In this study we observed that continuous fenoldopam infusion (0.06 mg/kg per minute) improved splanchnic perfusion without affecting systemic pressure. CONCLUSION: Patients undergoing OLT have altered splanchnic perfusion related to cirrhosis, surgical manipulation, and fluid shifts during and after surgery. The use of a splanchnic vasodilator drug improved outcomes in these patients.     

Evidence that Rho guanine nucleotide exchange factor 11 (ARHGEF11) on 1q21 is a type 2 diabetes susceptibility gene in the Old Order Amish

Rho guanine nucleotide exchange factor 11 (ARHGEF11), located on chromosome 1q21, is involved in G protein signaling and is a pathway known to play a role in both insulin secretion and action. We genotyped 52 single nucleotide polymorphims (SNPs) in ARHGEF11 and compared the genotype frequencies of subjects with type 2 diabetes (n = 145) or type 2 diabetes/impaired glucose tolerance (IGT) (n = 293) with those of control subjects with normal glucose tolerance (NGT) (n = 358). Thirty SNPs, spanning the entire gene, were significantly associated with type 2 diabetes or type 2 diabetes/IGT. The most significantly associated SNP was rs6427340 (intron 2), in which the less common allele was the risk allele (odds ratio [OR] 1.82 [95% CI 1.20-2.70], P = 0.005 for type 2 diabetes vs. NGT and 1.79 [1.27-2.50], P = 0.0008 for type 2 diabetes/IGT vs. NGT). In an expanded set of nondiabetic subjects (n = 754), most of the type 2 diabetes-and IGT-associated SNPs were significantly associated with glucose levels during an oral glucose tolerance test, with the same SNP (rs6427340) showing the most significant associations (P = 0.007). All type 2 diabetes-and IGT-associated SNPs were in high linkage disequilibrium and constitute a single 133-kb haplotype block. These results, coupled with similar findings in Pima Indians, suggest that sequence variation in ARHGEF11 may influence risk of type 2 diabetes.     

Evolution of hepatorenal syndrome after orthotopic liver transplantation: comparative analysis with patients who developed acute renal failure in the early postoperative period of liver transplantation

OBJECTIVE: The purpose of this study was to ascertain the prognosis of patients with hepatorenal syndrome (HS) prior to orthotopic liver transplantation (OLT) by comparisons with a group of selected patients with normal renal function (NRF) pretransplantation who developed acute renal failure (ARF) in the early postoperative period. MATERIALS AND METHODS: Fifty-two OLT cases developed ARF in the early postoperative period between March 1999 and October 2004; 17 cases experienced HS prior to OLT. ARF was defined as serum creatinine level (Cr) >1.5 mg/dL or a creatinine clearance (CrCl) <50 mL/min. The immunosuppressive therapy was the same in both groups: low doses of tacrolimus were prescribed to reach trough levels of 5 ng/mL in the first week after OLT, where patients were administered monoclonal antibodies and corticosteroids. RESULTS: No differences were observed between the groups for gender, age or APACHE II Score in the first 24 hours after OLT. Patients with HS pretransplantation showed higher Cr and urea (U) levels than the other group (Cr: 2.1 +/- 0.8 HS vs 0.9 +/- 0.2, P = .000; U: 93.6 +/- 51.9 HS vs 42.1 +/- 19.3, P = .001). The ICU days of stay were similar (12.8 +/- 0.5 HS vs 19.7 +/- 15.2, P = .053). At the end of 1 year follow-up after OLT there were no differences in mortality (35% HS vs 26%), need for renal replacement therapy (23% HS vs 34%), infection (59% HS vs 51%), or rejection (6% HS vs 29%, P = .06). CONCLUSIONS: Patients with HS prior to OLT showed a similar prognosis to a group of selected patients with NRF pretransplantation, but developed ARF in the early postoperative period which was treated with monoclonal antibodies and low doses of tacrolimus.     

Disturbances in beta-cell function in impaired fasting glycemia

In a cross-sectional study, we assessed beta-cell function and insulin sensitivity index (ISI) with hyperglycemic clamps (10 mmol/l) in 24 subjects with impaired fasting glycemia (IFG, fasting plasma glucose [FPG] between 6.1 and 7.0 mmol/l), 15 type 2 diabetic subjects (FPG >7.0 mmol/l), and 280 subjects with normal fasting glycemia (NFG, FPG <6.1 mmol/l). First-phase insulin release (0-10 min) was lower in IFG (geometric mean 541 pmol/l.10 min; 95% confidence interval [CI] 416-702 pmol/l.10 min) and in type 2 diabetes (geometric mean 376 pmol/l.10 min; 95% CI 247-572 pmol/l.10 min) than NFG (geometric mean 814 pmol/l.10 min; 95% CI 759-873 pmol/l.10 min) (P < 0.001). Second-phase insulin secretion (140-180 min) was also lower in IFG (geometric mean 251 pmol/l; 95% CI 198-318 pmol/l; P = 0.026) and type 2 diabetes (geometric mean 157 pmol/l; 95% CI 105-235 pmol/l; P < 0.001) than NFG (geometric mean 295 pmol/l; 95% CI 276-315 pmol/l). IFG and type 2 diabetic subjects had a lower ISI (0.15 plus minus 0.02 and 0.16 plus minus 0.02 micromol/kg fat-free mass [FFM]/min/pmol/l, respectively) than NFG (0.24 plus minus 0.01 micromol/kg FFM/min/pmol/l, P < 0.05). We found a stepwise decline in first-phase (and second-phase) secretion in NFG subjects with progressive decline in oral glucose tolerance (P < 0.05). IFG subjects with impaired glucose tolerance (IGT) had lower first-phase secretion than NFG subjects with IGT (P < 0.02), with comparable second-phase secretion and ISI. NFG and IFG subjects with a diabetic glucose tolerance (2-h glucose >11.1 mmol/l) had a lower ISI than their respective IGT counterparts (P < 0.05). We conclude that the early stages of glucose intolerance are associated with disturbances in beta-cell function, while insulin resistance is seen more markedly in later stages.     

The burden of chronic kidney disease in long-term liver transplant recipients

BACKGROUND: Chronic kidney disease (CKD) is an important risk factor for morbidity and mortality post-liver transplantation (OLT). This study focused on investigating the incidence and risk factors associated with the development CKD after OLT. METHODS: We performed a retrospective cohort study of recipients followed at least 5 years at our institution. CKD was diagnosed and classified according to National Kidney Foundation and the Kidney Disease Outcomes Quality Initiative guidelines. RESULTS: There were 231 patients, 64% men, 67% Caucasian, 16% African-American, and 17% others, with a mean age of 56 +/- 13 years. The mean glomerular filtration rate (GFR) of the population was 56 +/- 28 mL/min/1.73 m2. CKD was defined as GFR less than 60 mL/min; 144 patients (61%) were identified as having CKD. When these patients were compared to the non-CKD group, the former were significantly older (62 +/- 9 vs 52 +/- 12 years, P = .03), more likely to be hypertensive (59% vs 38%, P = .003), and required more antihypertensive medications (0.83 +/- 0.81 vs 0.52 +/- 0.77, P = .02); 26% of all patients had diabetes. However, the incidence of diabetes (43.3% vs 19.3%, P = .02) as well as the incidence of insulin dependency (21.6% vs 12.5%, P = .001) was significantly higher in the CKD population. Mean uric acid levels were higher in CKD patients compared to non-CKD patients (8.00 +/- 2.00 mg/dL vs 6.70 +/- 1.99 mg/dL respectively, P = .001); patients with uric acid more than 6.0 had a 1.7 risk of having CKD. CONCLUSIONS: CKD defined as GFR < 60 mL/min is highly prevalent in long-term OLT survivors. Older age, elevated systolic blood pressure, insulin-dependent diabetes mellitus, and elevated uric acid levels are independently associated with CKD.     

Reversal of nonalcoholic hepatic steatosis, hepatic insulin resistance, and hyperglycemia by moderate weight reduction in patients with type 2 diabetes

To examine the mechanism by which moderate weight reduction improves basal and insulin-stimulated rates of glucose metabolism in patients with type 2 diabetes, we used (1)H magnetic resonance spectroscopy to assess intrahepatic lipid (IHL) and intramyocellular lipid (IMCL) content in conjunction with hyperinsulinemic-euglycemic clamps using [6,6-(2)H(2)]glucose to assess rates of glucose production and insulin-stimulated peripheral glucose uptake. Eight obese patients with type 2 diabetes were studied before and after weight stabilization on a moderately hypocaloric very-low-fat diet (3%). The diabetic patients were markedly insulin resistant in both liver and muscle compared with the lean control subjects. These changes were associated with marked increases in IHL (12.2 +/- 3.4 vs. 0.6 +/- 0.1%; P = 0.02) and IMCL (2.0 +/- 0.3 vs. 1.2 +/- 0.1%; P = 0.02) compared with the control subjects. A weight loss of only approximately 8 kg resulted in normalization of fasting plasma glucose concentrations (8.8 +/- 0.5 vs. 6.4 +/- 0.3 mmol/l; P < 0.0005), rates of basal glucose production (193 +/- 7 vs. 153 +/- 10 mg/min; P < 0.0005), and the percentage suppression of hepatic glucose production during the clamp (29 +/- 22 vs. 99 +/- 3%; P = 0.003). These improvements in basal and insulin-stimulated hepatic glucose metabolism were associated with an 81 +/- 4% reduction in IHL (P = 0.0009) but no significant change in insulin-stimulated peripheral glucose uptake or IMCL (2.0 +/- 0.3 vs. 1.9 +/- 0.3%; P = 0.21). In conclusion, these data support the hypothesis that moderate weight loss normalizes fasting hyperglycemia in patients with poorly controlled type 2 diabetes by mobilizing a relatively small pool of IHL, which reverses hepatic insulin resistance and normalizes rates of basal glucose production, independent of any changes in insulin-stimulated peripheral glucose metabolism.     

Effect of glucagon-like peptide-1(7-36)-amide on initial splanchnic glucose uptake and insulin action in humans with type 1 diabetes

In vitro studies indicate that glucagon-like peptide-1(7-36)-amide (GLP-1) can enhance hepatic glucose uptake. To determine whether GLP-1 increases splanchnic glucose uptake in humans, we studied seven subjects with type 1 diabetes on two occasions. On both occasions, glucose was maintained at approximately 5.5 mmo/l during the night using a variable insulin infusion. On the morning of the study, a somatostatin, glucagon, and growth hormone infusion was started to maintain basal hormone levels. Glucose (containing [3H]glucose) was infused via an intraduodenal tube at a rate of 20 micromol.kg(-1).min(-1). Insulin concentrations were increased to approximately 500 pmol/l while glucose was clamped at approximately 8.8 mmol/l for the next 4 h by means of a variable intravenous glucose infusion labeled with [6,6-2H2]glucose. Surprisingly, the systemic appearance of intraduodenally infused glucose was higher (P = 0.01) during GLP-1 infusion than saline infusion, indicating a lower (P < 0.05) rate of initial splanchnic glucose uptake (1.4 +/- 1.5 vs. 4.8 +/- 0.8 micromol.kg(-1).min(-1)). On the other hand, flux through the hepatic uridine-diphosphate- glucose pool did not differ between study days (14.2 +/- 5.5 vs. 13.0 +/- 4.2 micromol.kg(-1).min(-1)), implying equivalent rates of glycogen synthesis. GLP-1 also impaired (P < 0.05) insulin-induced suppression of endogenous glucose production (6.9 +/- 2.9 vs. 1.3 +/- 1.4 micromol.kg(-1).min(-1)), but caused a time-dependent increase (P < 0.01) in glucose disappearance (93.7 +/- 10.0 vs. 69.3 +/- 6.3 micromol.kg(-1).min(-1); P < 0.01) that was evident only during the final hour of study. We conclude that in the presence of hyperglycemia, hyperinsulinemia, and enterally delivered glucose, GLP-1 increases total body but not splanchnic glucose uptake in humans with type 1 diabetes.     

Model for End-Stage Liver Disease (MELD) score and organ allocation from cadaveric donors for 198 liver transplantation procedures performed in a single center

Since February 2002, the United Network for Organ Sharing (UNOS) proposed to adopt a modified version of the Model for End-Stage Liver Disease (MELD) to assign priority on the waiting list for orthotopic liver transplantation (OLT). In this study, we evaluated the impact of MELD score on liver allocation in a single center series of 198 liver recipients (mean age of patients, 52.21+/-8.92 years), considering the relationship between clinical urgency derived from MELD score (overall MELD, 18.7+/-6.83; MELD <15 in 69 patients, MELD >or=15 in 129 patients) and geographical distribution of cadaveric donors (inside/outside Liguria Region, 125/73). The waiting time for OLT was 230+/-248 days, whereas the 3-month and 1-year patient survivals were 87.37% and 79.79%, respectively. No difference was observed for MELD score retrospectively calculated for patients who underwent OLT before February 2002 (n=71) compared with MELD score calculated for patients who received a liver thereafter (18.26+/-6.68 vs 18.94+/-6.92; P= .504). No significant difference was found in waiting time before and after adoption of MELD score (213+/-183 vs 238+/-278 days; P= .500), or by stratifying patients for MELD <15/>or=15 (225+/-234 vs 232+/-256 days; P= .851). Using the geographical distribution of donors as a grouping variable (outside vs inside Liguria Region), no significance occurred for MELD score (19.68+/-7.42 vs 18.17+/-6.42; P= .135) or waiting time (211+/-226 vs 242+/-261 days; P= .394). In our series, more OLTs were performed among sicker patients and no differences were found in the management of livers procured from cadaveric donors outside or inside Liguria Region. However, further efforts are needed to reduce the waiting time among patients with higher MELD scores.     

Glucose-6-phosphatase flux in vitro is increased in type 2 diabetes

Despite the effects of hyperinsulinemia and hyperglycemia, 2 factors known to inhibit endogenous glucose production (EGP) in nondiabetic subjects, increased EGP is a consistent feature of type 2 diabetes. Recent studies have suggested that increased glucose-6-phosphatase (G6Pase) and/or decreased glucokinase (GK) may explain the increase in EGP. However, no studies to date have clearly established this relationship in type 2 diabetes. The present studies were designed to determine rates of EGP and the activities of G6Pase and GK in obese patients scheduled for gastric bypass surgery. The study group consisted of 14 obese nondiabetic subjects and 13 patients with type 2 diabetes (BMI 53.7 +/- 2.4 vs. 50.1 +/- 1.6 kg/m2). Rates of EGP were determined after an overnight fast with a 4-h infusion of [6,6]-D-glucose, and they were significantly higher in the type 2 diabetic patients (85.9 +/- 10.0 vs. 137.8 +/- 14.4 mg x m(-2) x min(-1), P < 0.001) despite greater plasma glucose (5.1 +/- 0.1 vs. 12.0 +/- 1.1 mmol/l) and similar insulin concentrations (130.8 +/- 19.8 vs. 112.8 +/- 16.2 pmol/l, NS). Moreover, resistance to insulin-induced suppression of EGP was observed in the patients with type 2 diabetes when insulin concentrations were increased from approximately 120 to 180 pmol/l. Hepatic G6Pase activity determined from freshly isolated microsomes was significantly increased in the type 2 diabetic patients compared with the obese control subjects (0.16 +/- 0.02 vs. 0.09 +/- 0.01 micromol x min(-1) x mg(-1) protein, P < 0.02), whereas levels of GK were decreased (1.20 +/- 0.16 vs. 2.01 +/- 0.01 micromol x min(-1) x mg(-1) protein, P < 0.01). Net flux through G6Pase was significantly increased in type 2 diabetic patients (P < 0.01). We conclude that increased EGP is mediated in part by increased G6Pase flux in type 2 diabetes.     

Cumulative risk of cardiovascular events after orthotopic liver transplantation

As survival after orthotopic liver transplantation (OLT) improves, cardiovascular (CV) disease has emerged as the leading cause of non-graft-related deaths. The aims of our study were to determine the cumulative risk of CV events after OLT and to analyze predictive risk factors for those experiencing a CV event after OLT. We identified all adult patients who underwent OLT at our institution for end-stage liver disease between October 1996 and July 2008. The cumulative risk of CV events after OLT was analyzed with the Kaplan-Meier method. Multivariate logistic regression analysis was used to identify factors independently associated with CV events after OLT. In all, 775 patients were included in our study cohort (mean age of 53.3 years, female proportion = 44%, Caucasian proportion = 84%, median follow-up = 40 months). The most common indications for OLT were hepatitis C virus (33.2%), alcohol (14.5%), and cryptogenic cirrhosis (12.7%). Eighty-three patients suffered 1 or more CV events after OLT. Posttransplant metabolic syndrome was more prevalent in patients with CV events versus patients with no CV events (61.4% versus 34.1%, P < 0.001). According to a multivariate analysis, independent predictors of CV events were an older age at transplantation [odds ratio (OR) = 1.2, addition of 95% confidence interval (CI) = 1.1-1.3, P = 0.006], male sex (OR = 2.0, 95% CI = 1.2-3.3, P = 0.01), posttransplant diabetes (OR = 2.0, 95% CI = 1.3-3.3, P = 0.003), posttransplant hypertension (OR = 1.8, 95% CI = 1.1-3.0, P = 0.02), and mycophenolate mofetil (OR = 2.0, 95% CI = 1.3-3.2, P = 0.003). Among post-OLT patients, the cumulative risk at 5 years of 13.5%, respectively. In conclusion, cardiac complications after liver transplantation are common (Approximately 10% of patients experience 1 or move cv events). Patients with posttransplant hypertension and diabetes, which are modifiable risk factors, are approximately twice as likely to experience a CV event.