Alberto Battezzati

Regulation of glucose homeostasis in humans with denervated livers.

The liver plays a major role in regulating glucose metabolism, and since its function is influenced by sympathetic/ parasympathetic innervation, we used liver graft as a model of denervation to study the role of CNS in modulating hepatic glucose metabolism in humans. 22 liver transplant subjects were randomly studied by means of the hyperglycemic/ hyperinsulinemic (study 1), hyperglycemic/isoinsulinemic (study 2), euglycemic/hyperinsulinemic (study 3) as well as insulin-induced hypoglycemic (study 4) clamp, combined with bolus-continuous infusion of [3-3H]glucose and indirect calorimetry to determine the effect of different glycemic/insulinemic levels on endogenous glucose production and on peripheral glucose uptake. In addition, postabsorptive glucose homeostasis was cross-sectionally related to the transplant age (range = 40 d-35 mo) in 4 subgroups of patients 2, 6, 15, and 28 mo after transplantation. 22 subjects with chronic uveitis (CU) undergoing a similar immunosuppressive therapy and 35 normal healthy subjects served as controls. The results showed that successful transplantation was associated with fasting glucose concentration and endogenous glucose production in the lower physiological range within a few weeks after transplantation, and this pattern was maintained throughout the 28-mo follow-up period. Fasting glucose (4. 55+/-0.06 vs. 4.75+/-0.06 mM; P = 0.038) and endogenous glucose production (11.3+/-0.4 vs. 12.9+/-0.5 micromol/[kg.min]; P = 0.029) were lower when compared to CU and normal patients. At different combinations of glycemic/insulinemic levels, liver transplant (LTx) patients showed a comparable inhibition of endogenous glucose production. In contrast, in hypoglycemia, after a temporary fall endogenous glucose production rose to values comparable to those of the basal condition in CU and normal subjects (83+/-5 and 92+/-5% of basal), but it did not in LTx subjects (66+/-7%; P < 0.05 vs. CU and normal subjects). Fasting insulin and C-peptide levels were increased up to 6 mo after transplantation, indicating insulin resistance partially induced by prednisone. In addition, greater C-peptide but similar insulin levels during the hyperglycemic clamp (study 1) suggested an increased hepatic insulin clearance in LTx as compared to normal subjects. Fasting glucagon concentration was higher 6 mo after transplantation and thereafter. During euglycemia/hyperinsulinemia (study 3), the insulin-induced glucagon suppression detectable in CU and normal subjects was lacking in LTx subjects; furthermore, the counterregulatory response during hypoglycemia was blunted. In summary, liver transplant subjects have normal postabsorptive glucose metabolism, and glucose and insulin challenge elicit normal response at both hepatic and peripheral sites. Nevertheless, (a) minimal alteration of endogenous glucose production, (b) increased concentration of insulin and glucagon, and (c) defective counterregulation during hypoglycemia may reflect an alteration of the liver-CNS-islet circuit which is due to denervation of the transplanted graft.

Reduction of insulin resistance by combined kidney-pancreas transplantation in Type 1 (insulin-dependent) diabetic patients

SummaryTo evaluate the effect of combined kidney and pancreas transplantation on insulin action and glucose metabolism, 15 Type 1 (insulin-dependent) diabetic patients who were undergoing combined kidney-pancreas transplantation were studied before transplantation by means of the euglycaemic hyperinsulinaemic clamp technique combined with 3-3H-glucose infusion and indirect calorimetry. Nine of the original 15 patients were studied again after four months and six after 12 months, successful combined kidney-pancreas transplantation with the same experimental protocol. Nine volunteers formed the group of normal subjects. Combined kidney-pancreas transplantation normalised hepatic glucose production and reduced peripheral insulin resistance in Type 1 diabetic uraemic patients, despite chronic immunosuppressive therapy. To further evaluate the hypothesis that residual insulin resistance was due to chronic steroid therapy, 11 additional subjects with chronic uveitis (six of whom were treated with only prednisone, and five treated only with cyclosporin) underwent the same protocol demonstrating a normal hepatic glucose production. The insulin-stimulated peripheral glucose uptake was reduced in the prednisone-treated group, but normal in cyclosporin-treated subjects. Four additional diabetic patients with a kidney transplant were also studied. They showed a peripheral insulin sensitivity intermediate between diabetic uraemic patients and patients after combined transplant. We conclude that short-term (one year) combined kidney-pancreas transplantation improves glucose metabolism by restoring normal rates of hepatic glucose production and reducing peripheral insulin resistance; chronic steroid therapy is the major determinant of residual reduced insulin action. Both kidney and pancreas substitution play a role in reducing peripheral insulin resistance.

The effects of maintenance doses of FK506 versus cyclosporin A on glucose and lipid metabolism after orthotopic liver transplantation

BACKGROUND Posttransplant diabetes mellitus (PTDM) has gained widespread attention due to the micro and macro-vascular complications that increase the morbidity and mortality of patients receiving solid organs. The higher incidence of PTDM has been mainly attributed to the immunosuppressive therapy. Therefore, this study compares the metabolic side effects of low dose maintenance therapy of FK-506 and Cyclosporin A (CsA) in 14 patients 1 year after orthotopic liver transplant and analyzes possible factors that contribute to the development of PTDM. METHODS Two groups (n=7) differing in their immunosuppressive regimen (FK506 or CsA) were matched to eight control subjects and compared to each other. The effects of in vivo insulin action were assessed by means of the euglycemic hyperinsulinemic clamp technique. Arginine stimulation tests at normo- (5.5 mM) and hyperglycemic (15 mM) levels were performed and the acute insulin, C-peptide, and glucagon response (2-5 min) to arginine were determined. RESULTS Insulin sensitivity (total glucose disposal) was statistically lower in patients treated with FK-506 and CsA (5.05+/-0.47 and 5.05+/-0.42 mg/kg/min) as compared to controls (6.62+/-0.38 mg/kg/min) (P<0.02), with a significantly higher nonoxidative glucose disposal for the control group (P<0.01), and lower free fatty acid levels (P<0.05). Absolute values for acute insulin response were higher but not significantly different for the transplanted groups. The lower percentage of increase of insulin release after arginine stimulation observed in the FK-506 and CsA groups as compared with controls (754%+/-100, 644%+/-102 vs. 1191%+/-174) (P<0.03 and 0.02, respectively), suggests a reduced beta cell secretory reserve in both treated groups. Also, the acute glucagon response to arginine during hyperglycemia declined less in the FK-506 (28%) and CsA groups (29%) compared with controls (48%) (P<0.05) indicating a defect in the pancreatic beta cell-alpha cell axis. CONCLUSIONS There are no major metabolic differences on low maintenance doses between FK-506 and CsA. Both immunosuppressant agents contribute to the development of PTDM at different levels.

Cultivation, Genetic, Ethnopharmacology, Phytochemistry and Pharmacology of Moringa oleifera Leaves: An Overview.

Moringa oleifera is an interesting plant for its use in bioactive compounds. In this manuscript, we review studies concerning the cultivation and production of moringa along with genetic diversity among different accessions and populations. Different methods of propagation, establishment and cultivation are discussed. Moringa oleifera shows diversity in many characters and extensive morphological variability, which may provide a resource for its improvement. Great genetic variability is present in the natural and cultivated accessions, but no collection of cultivated and wild accessions currently exists. A germplasm bank encompassing the genetic variability present in Moringa is needed to perform breeding programmes and develop elite varieties adapted to local conditions. Alimentary and medicinal uses of moringa are reviewed, alongside the production of biodiesel. Finally, being that the leaves are the most used part of the plant, their contents in terms of bioactive compounds and their pharmacological properties are discussed. Many studies conducted on cell lines and animals seem concordant in their support for these properties. However, there are still too few studies on humans to recommend Moringa leaves as medication in the prevention or treatment of diseases. Therefore, further studies on humans are recommended.

Metabolic effects of successful intraportal islet transplantation in insulin-dependent diabetes mellitus

The intraportal injection of human pancreatic islets has been indicated as a possible alternative to the pancreas transplant in insulin-dependent diabetic patients. Aim of the present work was to study the effect of intraportal injection of purified human islets on: (a) the basal hepatic glucose production; (b) the whole body glucose homeostasis and insulin action; and (c) the regulation of insulin secretion in insulin-dependent diabetes mellitus patients bearing a kidney transplant. 15 recipients of purified islets from cadaver donors (intraportal injection) were studied by means of the infusion of labeled glucose to quantify the hepatic glucose production. Islet transplanted patients were subdivided in two groups based on graft function and underwent: (a) a 120-min euglycemic insulin infusion (1 mU/kg/min) to assess insulin action; (b) a 120-min glucose infusion (+75 mg/di) to study the pattern of insulin secretion. Seven patients with chronic uveitis on the same immunosuppressive therapy as grafted patients, twelve healthy volunteers, and seven insulin-dependent diabetic patients with combined pancreas and kidney transplantation were also studied as control groups. Islet transplanted patients have: (a) a higher basal hepatic glucose production (HGP: 5.1 +/- 1.4 mg/kg/ min; P < 0.05 with respect to all other groups) if without graft function, and a normal HGP (2.4 +/- 0.2 mg/kg/min) with a functioning graft; (b) a defective tissue glucose disposal (3.9 +/- 0.5 mg/kg/min in patients without islet function and 5.3 +/- 0.4 mg/kg/min in patients with islet function) with respect to normals (P < 0.01 for both comparisons); (c) a blunted first phase insulin peak and a similar second phase secretion with respect to controls. In conclusion, in spite of the persistence of an abnormal pattern of insulin secretion, successful intraportal islet graft normalizes the basal HGP and improves total tissue glucose disposal in insulin-dependent diabetes mellitus.

Lack of Feedback Inhibition of Insulin Secretion in Denervated Human Pancreas

In this study, pancreas transplantation is used as a clinical model of pancreas denervation in humans. To assess the role of innervation on the feedback autoinhibition of insulin secretion, we studied four groups of subjects--group 1: 16 patients with combined pancreas and kidney transplantation (plasma glucose = 5.1 mM, HbA1c = 6.4%, creatinine = 86 mM); group 2: 8 patients with chronic uveitis on the same immunosuppressive therapy as transplanted patients (12 mg/day prednisone, 5 mg.kg-1.day-1 CsA); group 3: 4 uremic, nondiabetic patients in chronic hemodialysis; group 4: 7 normal, nondiabetic control subjects. The following means were used to study the groups: 1) a two-step hyperinsulinemic euglycemic clamp (insulin infusion rate = 1 mU and 5 mU.kg-1.min-1); and 2) a 0.3 mU.kg-1.min-1 hypoglycemic clamp (steady-state plasma glucose = 3.1 mM). Basal plasma-free IRI (84 +/- 6, 42 +/- 12, 72 +/- 12, and 30 +/- 6 pM in groups 1, 2, 3, and 4, respectively), basal C-peptide (0.79 +/- 0.05, 0.66 +/- 0.05, 3.04 +/- 0.20, and 0.59 +/- 0.06 nM in groups 1, 2, 3, and 4, respectively), and glucagon (105 +/- 13, 69 +/- 4, 171 +/- 10, and 71 +/- 5 pg/ml in groups 1, 2, 3, and 4, respectively) were increased in groups 1 and 3 with respect to groups 2 and 4 (P < 0.01). During euglycemic hyperinsulinemia, plasma C-peptide decreased by 45, 20, and 44% in groups 2, 3, and 4, respectively, but showed no significant change from the basal in patients with transplanted pancreases.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of liver transplantation on the nutritional status of patients with cystic fibrosis.

The long‐term effects of liver transplantation on nutritional status, body composition and pulmonary function in patients with liver disease associated with cystic fibrosis (CF) are poorly defined. We studied 15 patients with CF‐associated biliary cirrhosis and severe portal hypertension. Seven underwent liver transplantation (age: 14.8 ± 6.2 years), and eight were treated conservatively (age: 15.9 ± 6.7 years). All patients were evaluated at baseline and thereafter yearly for a median duration of 5 years. During follow‐up, transplanted patients gained weight and showed a significant increment in body mass index (P < 0.004), whereas patients without transplantation remained stable (P = 0.063). Baseline bone mineral content (dual energy X‐ray absorptiometry scan) was lower than normal in all patients (more in transplanted patients) and increased in transplanted patients (P < 0.05), but not in patients without transplantation. In both groups percent body fat did not change, whereas fat free mass increased only in the transplant group (P = 0.06) (P < 0.03 versus nontransplanted patients). Only in transplanted patients’ plasma concentrations of vitamin E and A increased (P < 0.05 versus nontransplanted patients). Forced espiratory volume in 1 s and forced vital capacity showed similar deterioration in transplanted and in nontransplanted patients. Liver transplantation is associated with long‐term beneficial effects on the nutritional status of CF patients and seems to favor bone mineralization.

Metabolic effects of liver transplantation in cirrhotic patients.

To assess whether liver transplantation (LTx) can correct the metabolic alterations of chronic liver disease, 14 patients (LTx-5) were studied 5+/-1 mo after LTx, 9 patients (LTx-13) 13+/-1 mo after LTx, and 10 patients (LTx-26) 26+/-2 months after LTx. Subjects with chronic uveitis (CU) and healthy volunteers (CON) were also studied. Basal plasma leucine and branched-chain amino acids were reduced in LTx-5, LTx-13, and LTx-26 when compared with CU and CON (P < 0.01). The basal free fatty acids (FFA) were reduced in LTx-26 with respect to CON (P < 0.01). To assess protein metabolism, LTx-5, LTx-13, and LTx-26 were studied with the [1-14C]leucine turnover combined with a 40-mU/m2 per min insulin clamp. To relate changes in FFA metabolism to glucose metabolism, eight LTx-26 were studied with the [1-14C]palmitate and [3-3H]glucose turnovers combined with a two-step (8 and 40 mU/m2 per min) euglycemic insulin clamp. In the postabsorptive state, LTx-5 had lower endogenous leucine flux (ELF) (P < 0.005), lower leucine oxidation (LO) (P < 0.004), and lower non-oxidative leucine disposal (NOLD) (P < 0.03) with respect to CON (primary pool model). At 2 yr (LTx-26) both ELF (P < 0.001 vs. LTx-5) and NOLD (P < 0.01 vs. LTx-5) were normalized, but not LO (P < 0.001 vs. CON) (primary and reciprocal pool models). Suppression of ELF by insulin (delta-reduction) was impaired in LTx-5 and LTx-13 when compared with CU and CON (P < 0.01), but normalized in LTx-26 (P < 0.004 vs. LTx-5 and P = 0.3 vs. CON). The basal FFA turnover rate was decreased in LTx-26 (P < 0.01) and CU (P < 0.02) vs. CON. LTx-26 showed a lower FFA oxidation rate than CON (P < 0.02). Tissue glucose disposal was impaired in LTx-5 (P < 0.005) and LTx-13 (P < 0.03), but not in LTx-26 when compared to CON. LTx-26 had normal basal and insulin-modulated endogenous glucose production. In conclusion, LTx have impaired insulin-stimulated glucose, FFA, and protein metabolism 5 mo after surgery. Follow-up at 26 mo results in (a) normalization of insulin-dependent glucose metabolism, most likely related to the reduction of prednisone dose, and, (b) maintenance of some alterations in leucine and FFA metabolism, probably related to the functional denervation of the graft and to the immunosuppressive treatment.

Indirect calorimetry and nutritional problems in clinical practice

Abstract Indirect calorimetry is a simple and affordable tool for measuring energy expenditure and for quantifying the utilization of macronutrients. Its use is becoming increasingly widespread, but it is necessary to know its methodological features and its theoretical and practical limitations. Indirect calorimetry measures the rate of resting energy expenditure (REE), the major component of the total daily energy expenditure. Thus, indirect calorimetry reliably estimates the individual energy needs. Coupling the measurement of body composition to that of REE expands the diagnostic potential of indirect calorimetry. Once the lean and fat compartments have been measured, it is possible to establish on the basis of REE whether an individual is hyper- or hypometabolic. The evaluation of substrate oxidation by indirect calorimetry is subject to more severe theoretical constraints, because certain metabolic assumptions must be made. The clinical applications are practically unlimited. In the critically ill, a major goal is to maintain energy balance during the hypermetabolic response following trauma. The REE measurement is valuable from the diagnostic standpoint, because it recognizes discrepancies from the expected time-course of hypermetabolism, for example signaling a potentially catastrophic hypometabolic response. REE is also indispensable for providing correct nutritional support because both hyper- and undernutrition lead to increased mortality. In young or elderly patients, in whom energy consumption may be very different from that predicted from equations based on anthropometric measures, indirect calorimetry is particularly useful.

Persistence of counter-regulatory abnormalities in insulin-dependent diabetes mellitus after pancreas transplantation.

Abstract Conventional insulin therapy does not correct the counter‐regulatory abnormalities of insulin‐dependent diabetes mellitus. Pancreas transplantation is an alternative therapy that restores the endogenous insulin secretion in diabetes. In this study, the effects of segmental pancreas transplantation on counter‐regulation to mild hypoglycaemia were evaluated. Glucose kinetics and the counter‐regulatory hormonal responses were assessed in eight insulin‐dependent diabetics with end‐stage renal failure who had received pancreas and kidney transplantation 1 year previously, seven diabetic uraemic subjects (candidates for combined transplantation), five patients with chronic uveitis on immunosuppressive therapy comparable to pancreas recipients and 10 normal subjects. Insulin (0·3 mU kg‐1 min‐1) was infused for 2h to induce mild hypoglycaemia (plasma glucose 3·2–3·5‐mmol l‐1) and exogenous glucose was infused as required to prevent any glucose decrease below 3·1 mmol l‐1. After transplantation, two of eight recipients had hypoglycaemic episodes reported in their medical records. During the study, hepatic glucose production was rapidly suppressed in the controls and in the patients on immunsuppression (–80 ± 7 and –54 ± 7%, P < 0·001 vs. basal), and rebounded to the baseline values within 1 h (–3 ± 1 and –6 ± 2%, P= NS vs. basal). The transplant recipients had similar suppression in the first hour (–88 ± 8%, P < 0·001 vs. basal), but the suppression persisted in the second hour (–69 ± 11%, P < 0·001 vs. basal) indicating a lack of glucose counter‐regulatory response. The uraemic‐diabetics had reduced suppression of hepatic glucose production (–45 ± 14%, P < 0·001 vs. basal) with respect to the recipients (P < 0·001), but had the same lack of response in the second hour (suppression: –39 ± 12%, P < 0·001 vs. basal). In addition, the response of glucagon to hypoglycaemia was blunted in both the recipients and in the diabetic subjects. In conclusion, the alterations in glucose counter‐regulation of insulin‐dependent diabetes persists after segmental pancreas transplantation. Specifically, the increased sensitivity of hepatic glucose production to the action of insulin renders this defect more evident after transplantation.