Cross-sectional assessment of the effect of kidney and kidney-pancreas transplantation on resting left ventricular energy metabolism in type 1 diabetic-uremic patients: a phosphorous-31 magnetic resonance spectroscopy study

Diabetes current and future translatable therapies

Diabetes is one of the major diseases and concerns of public health systems that affects over 200 million patients worldwide. It is estimated that 90% of these patients suffer from diabetes type 2, while 10% present diabetes type 1. This type of diabetes and certain types of diabetes type 2, are characterized by dysregulation of blood glycemic levels due to the total or partial depletion of insulin-secreting pancreatic β-cells. Different approaches have been proposed for long-term treatment of insulin-dependent patients; amongst them, cell-based approaches have been the subject of basic and clinical research since they allow blood glucose level sensing and in situ insulin secretion. The current gold standard for insulin-dependent patients is on-demand exogenous insulin application; cell-based therapies aim to remove this burden from the patient and caregivers. In recent years, protocols to isolate and implant pancreatic islets from diseased donors have been developed and tested in clinical trials. Nevertheless, the shortage of donors, along with the need of immunosuppressive companion therapies, have pushed researchers to focus their attention and efforts to overcome these disadvantages and develop alternative strategies. This review discusses current tested clinical approaches and future potential alternatives for diabetes type 1, and some diabetes type 2, insulin-dependent patients. Additionally, advantages and disadvantages of these discussed methods.

Left Ventricular Hypertrophy After Renal Transplantation: Systematic Review and Meta-analysis

Background

Left ventricular hypertrophy (LVH) in patients with end stage renal disease undergoing renal replacement is linked to an increased risk for cardiovascular diseases. Dialysis does not completely prevent or correct this abnormality, and the evidence for kidney transplantation (KT) varies. This analysis aims to explore the relationship between KT and LVH.

Methods

MEDLINE and Scopus were systematically searched in October 2023. All cross-sectional and longitudinal studies that fulfilled our inclusion criteria were included. Outcome was left ventricular mass index (LVMI) changes. We conducted a meta-analysis using a random effects model. Meta-regression was applied to examine the LVMI changes dependent on various covariates. Sensitivity analysis was used to handle outlying or influential studies and address publication bias.

Results

From 7416 records, 46 studies met the inclusion criteria with 4122 included participants in total. Longitudinal studies demonstrated an improvement of LVMI after KT -0.44 g/m2 (-0.60 to -0.28). Blood pressure was identified as a predictor of LVMI change. A younger age at the time of KT and well-controlled anemia were also associated with regression of LVH. In studies longitudinally comparing patients on dialysis and renal transplant recipients, no difference was detected -0.09 g/m2 (-0.33 to 0.16). Meta-regression using changes of systolic blood pressure as a covariate showed an association between higher blood pressure and an increase in LVMI, regardless of the modality of renal replacement treatment.

Conclusions

In conclusion, our results indicated a potential cardiovascular benefit, defined as the regression of LVH, after KT. This benefit was primarily attributed to improved blood pressure control rather than the transplantation itself.

Early lung diffusion abnormalities and airways' inflammation in children with type 1 diabetes

BACKGROUND AND AIMS OF THE STUDY

Type 1 diabetes (T1D) impacts lung function and exercise capacity in adults, but limited information is available in children. We hypothesize that T1D causes alterations in pulmonary function and cardiorespiratory fitness, i.e., exercise capacity, at early stages of the disease, due to the presence of inflammation and vascular damage. Therefore, we aim to investigate pulmonary function before and after exercise in children with T1D as compared to age matched healthy controls.

METHOD

Twenty-four children with T1D and twenty healthy controls underwent body plethysmography, diffusion lung capacity for carbon monoxide and fractional exhaled nitric oxide at rest and after cardio-pulmonary exercise test.

RESULTS

In children with T1D, baseline total lung capacity and diffusion lung capacity for carbon monoxide were reduced as compared to healthy controls. Children with T1D also showed a reduced exercise capacity associated with poor aerobic fitness. Accordingly, diffusion lung capacity for carbon monoxide tended to increase with exercise in healthy controls, while no change was observed in children with T1D. Fractional exhaled nitric oxide was significantly higher at baseline and tended to increase with exercise in children with T1D, while no changes were observed in healthy controls.

CONCLUSIONS

Altered diffusion lung capacity for carbon monoxide, increased fractional exhaled nitric oxide and a poor aerobic fitness to exercise suggests the presence of early pulmonary abnormalities in children with T1D.

Daytime hypoglycemic episodes during the use of an advanced hybrid closed loop system

AIMS

The use of advanced hybrid closed loop systems is spreading due to the beneficial effects on glycometabolic control obtained in patients with type 1 diabetes. However, hypoglycemic episodes can be sometimes a matter of concern. We aim to compare the hypoglycemic risk of an advanced hybrid closed loop system and a predictive low glucose suspend sensor augmented pump.

METHODS

In this retrospective three months observational study, we included 30 patients using Medtronic Minimed™ 780G advanced hybrid closed loop system and 30 patients using a Medtronic Minimed™ predictive low glucose suspend sensor augmented pump.

RESULTS

The advanced hybrid closed loop system reduced the time spent above 180 mg/dL threshold and increased the time in range as compared to the predictive low glucose suspend. No severe hypoglycemia occurred in both groups and no differences were observed in the percentage of time spent below 70 mg/dl and 54 mg/dl glucose threshold. Nevertheless, more hypoglycemic episodes were recorded during daytime, but not in nighttime, with the use of the advanced hybrid closed loop system.

CONCLUSIONS

Our results confirmed the general improvement of glycemic outcomes obtained with the advanced hybrid closed loop system; however more hypoglycemic episodes during daytime were evident.

The anti-inflammatory and immunological properties of SGLT-2 inhibitors

BACKGROUND

Sodium-glucose cotransporter-2 inhibitors (SGLT-2i) are antidiabetic oral drugs that act on proximal renal tubules promoting renal glucose excretion. Although SGLT-2i belong to the class of hypoglycemic agents, in the last years great interest has emerged in studying their pleiotropic effects, beyond their ability to lower glucose levels.

PURPOSE

In this review we are describing the anti-inflammatory and immunological properties of SGLT-2i; furthermore, we are addressing how the mechanisms associated with the aforementioned anti-inflammatory properties may contribute to the beneficial effects of SGLT-2i in diabetes.

METHODS

A systematic search was undertaken for studies related the properties of SGLT-2i in reducing the inflammatory milieu of acute and chronic disease by acting on the immune system, independently by glycemia.

RESULTS

Recently, some data described the anti-inflammatory and immunological properties of SGLT-2 in both pre-clinical and clinical studies. Numerous data confirmed the cardio- and -renal protective effects of SGLT-2i in patients with heart failure and kidney diseases, with or without diabetes.

CONCLUSIONS

SGLT-2i are promising drugs with anti-inflammatory and immunological properties. Despite the mechanism of action of SGLT-2i is not fully understood, these drugs demonstrated anti-inflammatory effects, which may help in keeping under control the variety of complications associated with diabetes.

GLP-1 Receptor Agonist Improves Mitochondrial Energy Status and Attenuates Nephrotoxicity In Vivo and In Vitro

High-sugar and high-fat diets cause significant harm to health, especially via metabolic diseases. In this study, the protective effects of the antidiabetic drug exenatide (synthetic exendin-4), a glucagon-like peptide 1 (GLP-1) receptor agonist, on high-fat and high-glucose (HFHG)-induced renal injuries were investigated in vivo and in vitro. In vivo and in vitro renal injury models were established. Metabolomic analysis based on 1H-nuclear magnetic resonance was performed to examine whether exenatide treatment exerts a protective effect against kidney injury in diabetic rats and to explore its potential molecular mechanism. In vivo, 8 weeks of exenatide treatment resulted in the regulation of most metabolites in the diabetes mellitus group. In vitro results showed that exendin-4 restored the mitochondrial functions of mesangial cells, which were perturbed by HFHG. The effects of exendin-4 included the improved antioxidant capacity of mesangial cells, increased the Bcl-2/Bax ratio, and reduced protein expression of cyt-c and caspase-3 activation. In addition, exendin-4 restored mesangial cell energy metabolism by increasing succinate dehydrogenase and phosphofructokinase activities and glucose consumption while inhibiting pyruvate dehydrogenase E1 activity. In conclusion, GLP-1 agonists improve renal injury in diabetic rats by ameliorating metabolic disorders. This mechanism could be partially related to mitochondrial functions and energy metabolism.

Broadening horizons in mechanisms, management, and treatment of diabetic kidney disease

Diabetic kidney disease (DKD) is the first cause of end-stage kidney disease in patients with diabetes and its prevalence is increasing worldwide. It encompasses histological alterations that mainly affect the glomerular filtration unit, which include thickening of the basement membrane, mesangial cell proliferation, endothelial alteration, and podocyte injury. These morphological abnormalities further result in a persistent increase of urinary albumin-to-creatinine ratio and in a reduction of the estimated glomerular filtration rate. Several molecular and cellular mechanisms have been recognized, up to date, as major players in mediating such clinical and histological features and many more are being under investigation. This review summarizes the most recent advances in understanding cell death mechanisms, intracellular signaling pathways and molecular effectors that play a role in the onset and progression of diabetic kidney damage. Some of those molecular and cellular mechanisms have been already successfully targeted in preclinical models of DKD and, in some cases, strategies have been tested in clinical trials. Finally, this report sheds light on the relevance of novel pathways that may become therapeutic targets for future applications in DKD.

Continuous glucose monitoring in patients with type 2 diabetes on hemodialysis

Diabetic kidney disease is the leading cause of end-stage kidney disease in high-income countries. The strict control of glycemic oscillations is the principal therapeutic target, but this could be hard to achieve in uremic patients due to their unpredictable insulin sensitivity. Currently, the evaluation of the glycemic profile relies on serum markers (glycated hemoglobin HbA1c, glycated albumin, and fructosamine), capillary glucose blood control (self-monitoring of blood glucose), and interstitial glucose control (continue glucose monitoring). We conducted a systematic review of published articles on continue glucose monitoring in hemodialysis patients with type 2 diabetes, which included 12 major articles. Four studies found significant fluctuations in glucose levels during hemodialysis sessions. All studies reported a higher mean amplitude of glucose variations on the hemodialysis day. Three studies agreed that continue glucose monitoring is better than glycated hemoglobin in detecting these abnormalities. Moreover, continue glucose monitoring was more accurate and perceived as easier to use by patients and their caregivers. In patients with type 2 diabetes on hemodialysis, glucose levels show different variation patterns than the patients on hemodialysis without diabetes. Considering manageability, accuracy, and cost-effectiveness, continue glucose monitoring could be the ideal diagnostic tool for the patient with diabetes on hemodialysis.

Ectopic Fat Accumulation in Pancreas and Heart

Ectopic fat is found in liver, muscle, and kidney and is known to accumulate as visceral fat. In recent years, ectopic fat has also been observed in the pancreas, and it has been said that pancreatic fat accumulation is related to the pathophysiology of diabetes and the onset of diabetes, but the relationship has not yet been determined. In the heart, epicardium fat is another ectopic fat, which is associated with the development of coronary artery disease. Ectopic fat is also observed in the myocardium, and diabetic patients have more fat accumulation in this tissue than nondiabetic patients. Myocardium fat is reported to be related to diastolic cardiac dysfunction, which is one of the characteristics of the complications observed in diabetic patients. We recently reported that ectopic fat accumulation was observed in coronary arteries of a type 2 diabetic patient with intractable coronary artery disease, and coronary artery is attracting attention as a new tissue of ectopic fat accumulation. Here, we summarize the latest findings focusing on the relationship between ectopic fat accumulation in these organs and diabetic pathophysiology and complications, then describe the possibility of future treatments targeting these ectopic fat accumulations.

Deceased organ donor factors influencing pancreatic graft transplantation and survival

Criteria for organ acceptance in brain-dead organ donors remain inconsistent, especially when concerning pancreatic transplants. We sought to examine donor-specific predictors of pancreatic graft use and survival to better guide the selection and management of potential donors. A prospective observational study of all donors from ten organ procurement organizations was conducted from March 2012 to January 2015. Critical care endpoints were collected at 4 standardized time points. Data associated with pancreatic transplantation and graft survival rates were first determined using univariate analyses, and then logistic regression was used to identify independent predictors of these two outcomes. From 1819 donors, 238 (13.1%) pancreata were transplanted, and at a mean follow-up of 192 days, 218 (91.6%) grafts had survived. After regression analysis, donor age (OR = 0.89), HgbA1C (OR = 0.07), and achieving the donor management goal (DMG) for ejection fraction at allocation of ≥50% (OR = 3.29) remained as independent predictors of pancreatic utilization. On regression analysis, graft survival was independently predicted by lower donor age (OR = 0.93) and achieving the DMGs for mean arterial pressure (60-110 mm Hg) and glucose (≤180 mg/dL) at separate time points. These results may help guide the management and selection of potential pancreatic donors after brain death.

Non-invasive investigation of myocardial energetics in cardiac disease using 31P magnetic resonance spectroscopy

Cardiac metabolism and function are intrinsically linked. High-energy phosphates occupy a central and obligate position in cardiac metabolism, coupling oxygen and substrate fuel delivery to the myocardium with external work. This insight underlies the widespread clinical use of ischaemia testing. However, other deficits in high-energy phosphate metabolism (not secondary to supply-demand mismatch of oxygen and substrate fuels) may also be documented, and are of particular interest when found in the context of structural heart disease. This review introduces the scope of deficits in high-energy phosphate metabolism that may be observed in the myocardium, how to assess for them, and how they might be interpreted.

New Insights into Immunotherapy Strategies for Treating Autoimmune Diabetes

Type 1 diabetes mellitus (T1D) is an autoimmune illness that affects millions of patients worldwide. The main characteristic of this disease is the destruction of pancreatic insulin-producing beta cells that occurs due to the aberrant activation of different immune effector cells. Currently, T1D is treated by lifelong administration of novel versions of insulin that have been developed recently; however, new approaches that could address the underlying mechanisms responsible for beta cell destruction have been extensively investigated. The strategies based on immunotherapies have recently been incorporated into a panel of existing treatments for T1D, in order to block T-cell responses against beta cell antigens that are very common during the onset and development of T1D. However, a complete preservation of beta cell mass as well as insulin independency is still elusive. As a result, there is no existing T1D targeted immunotherapy able to replace standard insulin administration. Presently, a number of novel therapy strategies are pursuing the goals of beta cell protection and normoglycemia. In the present review we explore the current state of immunotherapy in T1D by highlighting the most important studies in this field, and envision novel strategies that could be used to treat T1D in the future.

Quercetin inhibited mesangial cell proliferation of early diabetic nephropathy through the Hippo pathway

Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes and the leading cause of end-stage renal disease. The proliferation of glomerular mesangial cells (MCs) is a common and prominent pathological change of DN, which takes place at the early stage. Quercetin, a bioflavonoid compound, possesses therapeutic efficacy in cardiovascular and kidney diseases via anti-tumour, anti-oxidation, anti-virus, and anti-proliferation effects. However, the mechanism of quercetin in the proliferation of glomerular MCs in early DN has not been reported. In the present study, we investigated the effect of quercetin on the proliferation of glomerular MCs in high glucose-induced mouse glomerular MCs and in db/db mice. On this basis, we tried to clarify the specific mechanisms underlying these effects. The in vitro results showed that the proliferation of glomerular MCs was induced by high glucose, and the Hippo pathway was highly inactivated in high glucose-cultured MCs. Decreased phosphorylation of MST1 and Lats1 promoted expression and nuclear translocation of Yes-associated protein (YAP) and subsequently increased the combination of YAP and TEA/ATS domain (TEAD), which promoted the expression of the downstream target gene such as cyclinE. Quercetin effectively inhibited the high glucose-induced MC proliferation and reactivated the Hippo pathway. In vivo, the proliferation of glomerular MCs was increased, renal function was decreased, and blood fasting glucose was elevated in db/db mice. Furthermore, the Hippo pathway was inactivated in the renal cortex of db/db mice. Eight-week treatment of quercetin retarded MC proliferation, alleviated the renal function, and reactivated Hippo pathway in the renal cortex of db/db mice at 16 weeks. Our previous study clarified that the Hippo pathway was involved in MC proliferation of DN. The results revealed that quercetin inhibited MC proliferation in high glucose-treated mouse glomerular MCs and in DN via reactivation of the Hippo pathway.

Short-term evaluation of cardiac morphology, function, metabolism and structure following diagnosis of adult-onset growth hormone deficiency

OBJECTIVE

The impact of growth hormone (GH) deficiency of the adult on cardiovascular function remains only partially elucidated. Purpose of this study was to test cardiac function in adult GH deficient patients using cardiac magnetic resonance (CMR).

DESIGN

Cardiac magnetic resonance (CMR) techniques, including cardiac ³¹P MR spectroscopy and evaluation of gadolinium late-enhancement, were applied to assess simultaneously, in a cross-sectional fashion, morphological, functional, metabolic, and structural parameters of the left (LV) and right ventricle (RV) in 15 patients with adult onset GH deficiency. Fifteen healthy individuals served as controls.

RESULTS

In GH deficient patients LV systolic function (EF%: 61 ± 1.7 vs 62.1 ± 0.8; p = .44) was not different in spite of a lower LV mass (83.2 ± 5.3 vs 145.3 ± 11.9 g; p = .001), a subclinical impairment of diastolic function (E/A peak ratio: 1.6 ± 0.2 vs 2.1 ± 0.2 p = .05), and a trend for lower PCr/ATP ratio (2.1 ± 0.8 vs 2.3 ± 0.1 p = .07). The RV showed reduced chamber size (end diastolic volume 123.8 ± 9 vs 147.9 ± 7.6 mL; p = .021) with preserved mass. No structural alterations of the LV and RV at late-enhancement were detected in these patients.

CONCLUSIONS

GH deficient patients represent a unique model of reduced LV myocardial mass in which major structural and metabolic alterations are lacking. Mal-adaptive mechanisms developing in the long term in response to GH deficiency and more severely affecting the LV remain to be elucidated.

Retrospective Analysis of Bone Metabolism in Patients on Waiting List for Simultaneous Pancreas-Kidney Transplantation

Posttransplant osteoporosis, which evolves from preexisting bone pathologies, represents a serious complication with deteriorating consequences. The aim of our study was to evaluate epidemiological data on bone mineral density (BMD) in subjects with type 1 diabetes (T1DM) in advanced stages of diabetic nephropathy indicated for simultaneous pancreas-kidney transplantation (SPK). We retrospectively compiled biochemical and densitometrical data from 177 patients with T1DM at CKD (chronic kidney disease) stages G4-G5 (115 men, 62 women, median age 40 yr, diabetes duration 23 yr) enrolled on waiting list for SPK for the first time between the years 2011 and 2016. Median Z-scores were as follows: lumbar spine (LS): -0.8 [interquartile range -1.75 to 0.1]; total hip (TH): -1.2 [-1.75 to -0.6]; femoral neck (FN): -1.2 [-1.9 to -0.7]; and distal radius (DR): -0.8 [-1.4 to -0.1]. We noted a gender difference in LS, with worse results for men (-1.1 vs. -0.3) even after adjusting for BMI (body mass index) and glomerular filtration (p < 0.001). Osteoporotic and osteopenic ranges (based on T-scores) for all major sites were 27.7% and 56.5%, respectively, with similar results across both genders. Women had a significantly higher proportion of normal BMD in LS than men (67.7 vs. 49.4%, p < 0.05). Patients with T1DM at CKD stages G4-G5 exhibited serious BMD impairment despite their young age. Men surprisingly displayed lower Z-scores and higher percentages of pathological BMD values in LS than women did. The introduction of adequate preventive measures during the advanced stages of diabetic nephropathy to prevent bone loss is recommended.

Bone marrow fat contributes to insulin sensitivity and adiponectin secretion in premenopausal women

PURPOSE

Bone marrow fat is a functionally distinct adipose tissue that may contribute to systemic metabolism. This study aimed at evaluating a possible association between bone marrow fat and insulin sensitivity indices.

METHODS

Fifty obese (n = 23) and non-obese (n = 27) premenopausal women underwent proton magnetic resonance spectroscopy to measure vertebral bone marrow fat content and unsaturation index at L4 level. Abdominal visceral, subcutaneous fat, and epicardial fat were also measured using magnetic resonance imaging. Bone mineral density was measured by dual-energy X-ray absorptiometry. Body composition was assessed by bioelectrical impedance analysis. Fasting serum glucose, insulin, lipids, adiponectin were measured; the insulin resistance index HOMA (HOMA-IR) was calculated.

RESULTS

Bone marrow fat content and unsaturation index were similar in obese and non-obese women (38.5 ± 0.1 vs. 38.6 ± 0.1%, p = 0.994; 0.162 ± 0.065 vs. 0.175 ± 0.048, p = 0.473, respectively). Bone marrow fat content negatively correlated with insulin and HOMA-IR (r = -0.342, r = -0.352, respectively, p = 0.01) and positively with high density lipoprotein cholesterol (r = 0.270, p = 0.043). From a multivariate regression model including lnHOMA-IR as a dependent variable and visceral, subcutaneous, epicardial fat, and bone marrow fat as independent variables, lnHOMA-IR was significantly associated with bone marrow fat (β = -0.008 ± 0.004, p = 0.04) and subcutaneous fat (β = 0.003 ± 0.001, p = 0.04). Bone marrow fat, among the other adipose depots, was a significant predictor of circulating adiponectin (β = 0.147 ± 0.060, p = 0.021). Bone marrow fat unsaturation index negatively correlated with visceral fat (r = -0.316, p = 0.026).

CONCLUSIONS

There is a relationship between bone marrow fat content and insulin sensitivity in obese and non-obese premenopausal women, possibly mediated by adiponectin secretion. Visceral fat does not seem to regulate bone marrow fat content while it may affect bone marrow fat composition.

Mouse Model for Pancreas Transplantation Using a Modified Cuff Technique

Mouse models have several advantages in transplantation research, including easy handling, a variety of genetically well-defined strains, and the availability of the widest range of molecular probes and reagents to perform in vivo as well as in vitro studies. Based on our experience with various murine transplantation models, we developed a heterotopic pancreas transplantation model in mice with the intent to analyze mechanisms underlying severe ischemia reperfusion injury-associated early graft damage. In contrast to previously described techniques using suture techniques, herein we describe a new procedure using a non-suture cuff technique.

In recent years, we have performed more than 300 pancreas transplantations in mice with an overall success rate of >90%, a success rate never described before in mouse pancreas transplantation. The backbone of this non-suture cuff technique for graft revascularization consists of two major steps: (I) pulling the recipient vessel over a polyethylene/polyamide cuff and fixing it with a circumferential ligature, and (II) placing the donor vessel over the everted recipient vessel and fixing it with a second circumferential ligature. The resultant continuity of the endothelial layer results in less thrombogenic lesions with high patency rates and, finally, high success rates.

In this model, arterial anastomosis is achieved by pulling the abdominal aorta of the donor graft over the everted common carotid artery of the recipient animal. Venous drainage of the graft is achieved by pulling the portal vein of the graft over the everted external jugular vein of the recipient. This manuscript provides details and crucial steps of the organ recovery and organ implantation procedures, which will allow researchers with microsurgical skills to perform the transplantation successfully in their laboratories.

Immunotherapy for type 1 diabetes

INTRODUCTION

Although many approaches have been tested to overcome the insulin dependence caused by the pancreatic β-cells destruction observed in individuals affected by type 1 diabetes (T1D), medical research has largely failed to halt the onset or to reverse T1D.

METHODS

In this work, the state of the art of immunotherapy will be examined, and the most important achievement in the field will be critically discussed. Particularly, we will focus on the clinical aspect, thus avoiding the tedious preclinical work done in NOD mice, which has been so poorly translated to the bedside.

CONCLUSIONS

Stem cell therapies achieved thus this far the most promising results, while immune ablation and standard immunosuppressants did not maintain the premises of preclinical results. The next step will be to generate a feasible and safe clinical approach in order to cure the thousands of patients affected by T1D.

Vitamin D, sub-inflammation and insulin resistance. A window on a potential role for the interaction between bone and glucose metabolism

Vitamin D is a key hormone involved in the regulation of calcium/phosphorous balance and recently it has been implicated in the pathogenesis of sub-inflammation, insulin resistance and obesity. The two main forms of vitamin D are cholecalciferol (Vitamin D3) and ergocalciferol (Vitamin D2): the active form (1,25-dihydroxyvitamin D) is the result of two hydroxylations that take place in liver, kidney, pancreas and immune cells. Vitamin D increases the production of some anti-inflammatory cytokines and reduces the release of some pro-inflammatory cytokines. Low levels of Vitamin D are also associated with an up-regulation of TLRs expression and a pro-inflammatory state. Regardless of the effect on inflammation, Vitamin D seems to directly increase insulin sensitivity and secretion, through different mechanisms. Considering the importance of low grade chronic inflammation in metabolic syndrome, obesity and diabetes, many authors hypothesized the involvement of this nutrient/hormone in the pathogenesis of these diseases. Vitamin D status could alter the balance between pro and anti-inflammatory cytokines and thus affect insulin action, lipid metabolism and adipose tissue function and structure. Numerous studies have shown that Vitamin D concentrations are inversely associated with pro-inflammatory markers, insulin resistance, glucose intolerance and obesity. Interestingly, some longitudinal trials suggested also an inverse association between vitamin D status and incident type 2 diabetes mellitus. However, vitamin D supplementation in humans showed controversial effects: with some studies demonstrating improvements in insulin sensitivity, glucose and lipid metabolism while others showing no beneficial effect on glycemic control and on inflammation. In conclusion, although the evidences of a significant role of Vitamin D on inflammation, insulin resistance and insulin secretion in the pathogenesis of obesity, metabolic syndrome and type 2 diabetes, its potential function in treatment and prevention of type 2 diabetes mellitus is unclear. Encouraging results have emerged from Vitamin D supplementation trials on patients at risk of developing diabetes and further studies are needed to fully explore and understand its clinical applications.

The incidence of new onset diabetes after transplantation and related factors: Single center experience

AIM

New-onset diabetes after transplantation (NODAT) is a frequent metabolic complication and is considered a risk factor for patients undergoing renal transplant. The aim of this study was to evaluate the incidence and developing duration of new-onset diabetes after transplant (NODAT) and influencing factors.

METHODS

All patients' data was investigated retrospectively. Diabetics, follow-up period<6 months, age<18years were excluded. Demographic, clinical and laboratory data was recorded. Patients were divided into two groups: with/without NODAT. NODAT group was divided into four subgroups according to the time of developing NODAT, which were 0-3, 3-6, 6-12 and 12 months later. Two groups were compared, to investigate the incidence of NODAT and risk factors associated with the occurrence of NODAT.

RESULTS

We retrospectively analyzed the records of 570 patients, of which 420 patients were included. Seventy (16.6%) patients had NODAT (36 female, mean age 51.7±8.2 years, mean follow-up 41.6±21.5 months), 52.8% of patients developed NODAT within the first three months of being diagnosed. 350 patients (116 female, mean age 43.2±12.5 years, mean follow-up 41.6±21.5 months) were without NODAT. The incidence of impaired fasting glucose (IFG) during the first week after transplant was found to be higher in the patients with NODAT (p<0.001). There was positive correlation between NODAT and older age, obesity, family history of diabetes, presence of IFG, fasting plasma glucose, total and LDL-cholesterol, triglycerides, parathormone. Old age, obesity, presence of IFG, pretransplant hypertriglyceridemia and hyperparathyroidism were predictors of development of NODAT.

CONCLUSION

Incidence of NODAT, especially the first six months, was high. All patients should be screened for IFG within the first week. Patients with dyslipidemia, elderly and obese patients should be closely monitored for the risk of development of NODAT.

Metabolomic Profiling in Individuals with a Failing Kidney Allograft

BACKGROUND

Alteration of certain metabolites may play a role in the pathophysiology of renal allograft disease.

METHODS

To explore metabolomic abnormalities in individuals with a failing kidney allograft, we analyzed by liquid chromatography-mass spectrometry (LC-MS/MS; for ex vivo profiling of serum and urine) and two dimensional correlated spectroscopy (2D COSY; for in vivo study of the kidney graft) 40 subjects with varying degrees of chronic allograft dysfunction stratified by tertiles of glomerular filtration rate (GFR; T1, T2, T3). Ten healthy non-allograft individuals were chosen as controls.

RESULTS

LC-MS/MS analysis revealed a dose-response association between GFR and serum concentration of tryptophan, glutamine, dimethylarginine isomers (asymmetric [A]DMA and symmetric [S]DMA) and short-chain acylcarnitines (C4 and C12), (test for trend: T1-T3 = p<0.05; p = 0.01; p<0.001; p = 0.01; p = 0.01; p<0.05, respectively). The same association was found between GFR and urinary levels of histidine, DOPA, dopamine, carnosine, SDMA and ADMA (test for trend: T1-T3 = p<0.05; p<0.01; p = 0.001; p<0.05; p = 0.001; p<0.001; p<0.01, respectively). In vivo 2D COSY of the kidney allograft revealed significant reduction in the parenchymal content of choline, creatine, taurine and threonine (all: p<0.05) in individuals with lower GFR levels.

CONCLUSIONS

We report an association between renal function and altered metabolomic profile in renal transplant individuals with different degrees of kidney graft function.

Challenges in pancreas transplantation

Whole-organ pancreas transplantation, either alone or combined with a kidney transplant, is the only definitive treatment for many patients with type 1 diabetes that restores normal glucose homoeostasis and insulin independence. Pancreas transplantation delays, or potentially prevents, secondary diabetes complications and is associated with improvement in patient survival when compared with either patients remaining on the waiting list or those receiving kidney transplant alone. Pancreas transplantation is safe and effective, with 1-year patient survival >97 % and graft survival rates of 85 % at 1 year and 76 % at 5 years in recent UK data. This review focuses on some current areas of interest in pancreas transplantation.

Myocardial bioenergetic abnormalities in experimental uremia

Purpose

Cardiac bioenergetics are known to be abnormal in experimental uremia as exemplified by a reduced phosphocreatine (PCr)/adenosine triphosphate (ATP) ratio. However, the progression of these bioenergetic changes during the development of uremia still requires further study and was therefore investigated at baseline, 4 weeks and 8 weeks after partial nephrectomy (PNx).

Methods

A two-stage PNx uremia model in male Wistar rats was used to explore in vivo cardiac and skeletal muscles’ bioenergetic changes over time. High-energy phosphate nucleotides were determined by phosphorus-31 nuclear magnetic resonance (³¹P-NMR) and capillary zone electrophoresis.

Results

³¹P-NMR spectroscopy revealed lower PCr/ATP ratios in PNx hearts compared to sham (SH)-operated animals 4 weeks after PNx (median values given ± SD, 0.64±0.16 PNx, 1.13±0.31 SH, P<0.02). However, 8 weeks after PNx, the same ratio was more comparable between the two groups (0.84±0.15 PNx, 1.04±0.44 SH, P= not significant), suggestive of an adaptive mechanism. When 8-week hearts were prestressed with dobutamine, the PCr/ATP ratio was again lower in the PNx group (1.08±0.36 PNx, 1.55±0.38 SH, P<0.02), indicating a reduced energy reserve during the progression of uremic heart disease. ³¹P-NMR data were confirmed by capillary zone electrophoresis, and the changes in myocardial bioenergetics were replicated in the skeletal muscle.

Conclusion

This study provides evidence of the changes that occur in myocardial energetics in experimental uremia and highlights how skeletal muscle bioenergetics mirror those found in the cardiac tissue and so might potentially serve as a practical surrogate tissue during clinical cardiac NMR investigations.

Effects of short-term manipulation of serum FFA concentrations on left ventricular energy metabolism and function in patients with heart failure: no association with circulating bio-markers of inflammation

BACKGROUND AND AIMS

We wanted to assess the effects of short-term changes in serum free fatty acids (FFAs) on left ventricular (LV) energy metabolism and function in patients with heart failure and whether they correlated with circulating markers of inflammation.

METHODS AND RESULTS

LV function and phosphocreatine (PCr)/ATP ratio were assessed using MR imaging (MRI) and 31P magnetic resonance spectroscopy (MRS) in 11 men with chronic heart failure in two experimental conditions 7 days apart. Study 1: MRI and 31P-MRS were performed before and 3-4 h after i.v. bolus + continuous heparin infusion titrated to achieve a serum FFA concentration of 1.20 mM. Study 2: The same protocol was performed before and after the oral administration of acipimox titrated to achieve a serum FFA concentration of 0.20 mM. Serum concentrations of IL6, TNF-α, PAI-1, resistin, visfatin and leptin were simultaneously assessed. Serum glucose and insulin concentrations were not different between studies. The PCr/ATP ratio (percent change from baseline: +6.0 ± 16.9 and -16.6 ± 16.1 % in Study 1 and Study 2, respectively; p = 0.005) and the LV ejection fraction (-1.5 ± 4.0 and -6.9 ± 6.3 % in Study 1 and Study 2, respectively; p = 0.044) were reduced during low FFA when compared to high FFA. Serum resistin was higher during Study 1 than in Study 2 (p < 0.05 repeated measures ANOVA); meanwhile, the other adipocytokines were not different.

CONCLUSION

FFA deprivation, but not excess, impaired LV energy metabolism and function within hours. Cautions should be used when sudden iatrogenic modulation of energy substrates may take place in vulnerable patients.

Diastolic dysfunction is an independent predictor of cardiovascular events in incident dialysis patients with preserved systolic function

Background

Diastolic heart failure (HF), the prevalence of which is gradually increasing, is associated with cardiovascular (CV) morbidity and mortality in the general population and, more specifically, in patients with end-stage renal disease (ESRD). However, the impact of diastolic dysfunction on CV outcomes has not been studied in incident dialysis patients with preserved systolic function.

Methods

This prospective observational cohort study investigates the clinical consequence of diastolic dysfunction and the predictive power of diastolic echocardiographic parameters for CV events in 194 incident ESRD patients with normal or near normal systolic function, who started dialysis between July 2008 and August 2012.

Results

During a mean follow-up duration of 27.2 months, 57 patients (29.4%) experienced CV events. Compared to the CV event-free group, patients with CV events had a significantly higher left ventricular (LV) mass index, ratio of early mitral flow velocity (E) to early mitral annulus velocity (E’) (E/E’), LA volume index (LAVI), deceleration time, and right ventricular systolic pressure, and a significantly lower LV ejection fraction and E’. In multivariate Cox proportional hazard analysis, E/E’>15 and LAVI>32 mL/m² significantly predicted CV events (E/E’>15: hazard ratio [HR] = 5.40, 95% confidence interval [CI] = 2.73–10.70, P< .001; LAVI>32 mL/m²: HR = 5.56, 95% CI = 2.28–13.59, P< .001]. Kaplan-Meier analysis revealed that patients with both E/E’>15 and LAVI>32mL/m² had the worst CV outcomes.

Conclusion

An increase in E/E’ or LAVI is a significant risk factor for CV events in incident dialysis patients with preserved LV systolic function.

Effects of restoring normoglycemia in type 1 diabetes on inflammatory profile and renal extracellular matrix structure after simultaneous pancreas and kidney transplantation

AIMS

Patients with type 1 diabetes and end-stage renal disease with simultaneous pancreas and kidney (SPK) or kidney transplants alone (KA) were recruited 9-12 years post transplantation. We investigated differences between these groups with regard to inflammatory parameters and long-term structural changes in kidneys.

METHODS

Blood samples were analyzed by ELISA and multiplex for chemokines, cytokines, growth factors, cell adhesion molecules and matrix metalloproteinases. Kidney graft biopsies were analyzed by electron microscopy for glomerular basement membrane thickness. Heparan- and chondroitin sulfate disaccharide structures were determined by size exclusion chromatography mass-spectrometry.

RESULTS

The SPK and the KA group had average glycated hemoglobin A1c (HbA1c) of 5.8% (40 mmol/mol) and 8.6% (70 mmol/mol) respectively. SPK recipients also had 16.2% lower body mass index (BMI) and 46.4% lower triglyceride levels compared with KA recipients, compatible with an improved metabolic profile in the SPK group. Plasminogen activator inhibitor (PAI-1), C-reactive protein (CRP) and vascular endothelial growth factor (VEGF) were lower in the SPK group. In kidney graft biopsies of the KA-patients an 81.2% increase in average glomerular basement membrane thickness was observed, accompanied by alterations in heparan sulfate proteoglycan structure. In addition to a decrease in 6-O-sulfated disaccharides, an increase in non-N-sulfated disaccharides with a corresponding slight decrease in N-sulfation was found in kidney biopsies from hyperglycemic patients.

CONCLUSIONS

Patients with end stage renal disease subjected to KA transplantation showed impaired inflammatory profile, increased thickness of basement membranes and distinct changes in heparan sulfate structures compared with SPK recipients.

Novel therapeutic approaches for diabetic nephropathy and retinopathy

Diabetes mellitus is a chronic disease that in the long-term increases the microvascular and macrovascular degenerative complications thus being responsible for a large part of death associated with diabetes. During the years, while preventive care for diabetic patients has improved, the increase in the prevalence of diabetes worldwide is continuous. The detrimental effects of diabetes mellitus result in microvascular diseases, which recognize hyperglycemia as major determinant. A significant number of potential therapeutic targets for the treatment of diabetic microvascular complications have been proposed, but the encouraging results obtained in preclinical studies, have largely failed in clinical trials. Currently, the most successful strategy to prevent microvascular complications of diabetes is the intensive treatment of hyperglycemia or the normalization of glycometabolic control achieved with pancreatic and islet transplantation. In this review, we focus on the novel therapeutic targets to prevent the development and progression of diabetic nephropathy and retinopathy microvascular complications.

Novel immunological strategies for islet transplantation

Islet transplantation has been demonstrated to improve glycometabolic control, to reduce hypoglycemic episodes and to halt the progression of diabetic complications. However, the exhaustion of islet function and the side effects related to chronic immunosuppression limit the spread of this technique. Consequently, new immunoregulatory protocols have been developed, with the aim to avoid the use of a life-time immunosuppression. Several approaches have been tested in preclinical models, and some are now under clinical evaluation. The development of new small molecules and new monoclonal or polyclonal antibodies is continuous and raises the possibility of targeting new costimulatory pathways or depleting particular cell types. The use of stem cells and regulatory T cells is underway to take advantage of their immunological properties and to induce tolerance. Xenograft islet transplantation, although having severe problems in terms of immunological compatibility, could theoretically provide an unlimited source of donors; using pigs carrying human immune antigens has showed indeed promising results. A completely different approach, the use of encapsulated islets, has been developed; synthetic structures are used to hide islet alloantigen from the immune system, thus preserving islet endocrine function. Once one of these strategies is demonstrated safe and effective, it will be possible to establish clinical islet transplantation as a treatment for patients with type 1 diabetes long before the onset of diabetic-related complications.

Influencing factors of new-onset diabetes after a renal transplant and their effects on complications and survival rate

OBJECTIVE

To discuss the onset of and relevant risk factors for new-onset diabetes after a transplant (NODAT) in patients who survive more than 1 year after undergoing a renal transplant and the influence of these risk factors on complications and long-term survival.

METHOD

A total of 428 patients who underwent a renal transplant between January 1993 and December 2008 and were not diabetic before surgery were studied. The prevalence rate of and relevant risk factors for postoperative NODAT were analyzed on the basis of fasting plasma glucose (FPG) levels, and differences in postoperative complications and survival rates between patients with and without NODAT were compared.

RESULTS

The patients in this study were followed up for a mean of 5.65 ± 3.68 years. In total, 87 patients (20.3%) developed NODAT. Patients who converted from treatment with CSA to FK506 had increased prevalence rates of NODAT (P <0.05). Multi-factor analysis indicated that preoperative FPG level (odds ratio [OR]  =  1.48), age (OR  =  1.10), body mass index (OR  =  1.05), hepatitis C virus infection (OR  =  2.72), and cadaveric donor kidney (OR  =  1.18) were independent risk factors for NODAT (All P <0.05). Compared with the N-NODAT group, the NODAT group had higher prevalence rates (P < 0.05) of postoperative infection, hypertension, and dyslipidemia; in addition, the survival rate and survival time of the 2 groups did not significantly differ.

CONCLUSION

Among the patients who survived more than 1 year after a renal transplant, the prevalence rate of NODAT was 20.32%. Preoperative FPG level, age, body mass index, hepatitis C virus infection, and cadaveric donor kidney were independent risk factors for NODAT. Patients who converted from treatment with CSA to FK506 after a renal transplant had aggravated impairments in glycometabolism. Patients with NODAT were also more vulnerable to postoperative complications such as infection, hypertension, and hyperlipidemia.

Diastolic dysfunction is associated with an increased risk of contrast-induced nephropathy: a retrospective cohort study

Background

Contrast-induced nephropathy (CIN) is the third leading cause of hospital-acquired acute kidney injury, and it is associated with poor long-term clinical outcomes. Although systolic heart failure is a well-known risk factor for CIN, no studies have yet evaluated the association between diastolic dysfunction and CIN.

Methods

We conducted a retrospective study of 735 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) and had an echocardiography performed within one month of the procedure at our institute, between January 2009 and December 2010. CIN was defined as an increase of ≥ 0.5 mg/dL or ≥ 25% in serum creatinine level during the 72 hours following PTCA.

Results

CIN occurred in 64 patients (8.7%). Patients with CIN were older, had more comorbidities, and had an intra-aortic balloon pump (IABP) placed more frequently during PTCA than patients without CIN. They showed greater high-sensitivity C-reactive protein (hs-CRP) levels and lower estimated glomerular filtration rates (eGFR). Echocardiographic findings revealed lower ejection fraction and higher left atrial volume index and E/E’ in the CIN group compared with non-CIN group. When patients were classified into 3 groups according to the E/E’ values of 8 and 15, CIN occurred in 42 (21.6%) patients in the highest tertile compared with 20 (4.0%) in the middle and 2 (4.3%) in the lowest tertile (p < 0.001). In multivariate logistic regression analysis, E/E’ > 15 was identified as an independent risk factor for the development of CIN after adjustment for age, diabetes, dose of contrast media, IABP use, eGFR, hs-CRP, and echocardiographic parameters [odds ratio (OR) 2.579, 95% confidence interval (CI) 1.082-5.964, p = 0.035]. In addition, the area under the receiver operating characteristic curve of E/E’ was 0.751 (95% CI 0.684-0.819, p < 0.001), which was comparable to that of ejection fraction and left atrial volume index (0.739 and 0.656, respectively, p < 0.001).

Conclusions

This study demonstrated that, among echocardiographic variables, E/E' was an independent predictor of CIN. This in turn suggests that diastolic dysfunction may be a useful parameter in CIN risk stratification.

Follow-up of secondary diabetic complications after pancreas transplantation

PURPOSE OF REVIEW

Successful pancreas transplantation restores physiologic glycemic and metabolic control. Its effects on overall patient survival (especially for simultaneous pancreas-kidney transplantation) are clear-cut. We herein review the available literature to define the impact of pancreas transplantation on chronic complications of diabetes mellitus.

RECENT FINDINGS

With longer-term follow-up, wider patient populations, and more accurate investigational tools (clinical and functional tests, noninvasive imaging, histology, and molecular biology), growing data show that successful pancreas transplantation may slow the progression, stabilize, and even favor the regression of secondary complications of diabetes, both microvascular and macrovascular, in a relevant proportion of recipients.

SUMMARY

Patients who are referred for pancreas transplantation usually suffer from advanced chronic complications of diabetes, which have classically been deemed irreversible. A successful pancreas transplantation is often able to slow the progression, stabilize, and even reverse many microvascular and macrovascular complications of diabetes. Growing clinical evidence shows that the expected natural history of long-term diabetic complications can be significantly modified by successful pancreas transplantation.

31P-magnetic resonance spectroscopy (31P-MRS) detects early changes in kidney high-energy phosphate metabolism during a 6-month Valsartan treatment in diabetic and non-diabetic kidney-transplanted patients

(31)P-magnetic resonance spectroscopy ((31)P-MRS) is a non-invasive tool to study high-energy phosphate (HEP) metabolism. We evaluate whether 31P-MRS can detect early changes in kidney HEP metabolism during a 6-month trial with Valsartan. Twenty consecutive stable and normotensive kidney-transplanted patients were enrolled. Nine of them received short-term low-dose Valsartan treatment (80 mg/day) for 6 months, while 11 controls received no medication. Kidney HEP metabolism was evaluated both at baseline and after treatment by (31)P-MRS with a 1.5 T system (Gyroscan Intera Master 1.5 MR System; Philips Medical Systems, Best, The Netherlands). Valsartan-treated patients (n = 9) showed a significant increase in β-ATP/Pi ratio, a marker of kidney HEP metabolism (baseline = 1.03 ± 0.08 vs. 6 months = 1.26 ± 0.07, p = 0.03). In contrast, the b-ATP/Pi ratio in the control group (n = 11) did not change (baseline = 0.85 ± 0.10 vs. 6 months = 0.89 ± 0.08, ns). The improvement in the β-ATP/Pi ratio was not associated with a reduction in arterial blood pressure or in urinary albumin excretion. Kidney-localized (31)P-MRS can detect early changes in kidney HEP metabolism during a short-term low-dose Valsartan treatment in stable normotensive kidney-transplanted patients.

[Clinical indications for the use of cardiac MRI. By the SIRM Study Group on Cardiac Imaging]

Cardiac magnetic resonance (CMR) is considered an useful method in the evaluation of many cardiac disorders. Based on our experience and available literature, we wrote a document as a guiding tool in the clinical use of CMR. Synthetically we describe different cardiac disorders and express for each one a classification, I to IV, depending on the significance of diagnostic information expected.

Altered relative concentrations of high-energy phosphates in patients with uraemic cardiomyopathy measured by magnetic resonance spectroscopy

BACKGROUND

Premature sudden cardiovascular death is the commonest cause of death in end-stage renal disease (ESRD) patients and is associated with uraemic cardiomyopathy [left ventricular hypertrophy (LVH), systolic dysfunction (LVSD) or LV dilation]. High-energy phosphates (HEP), quantified using phosphorus-31 magnetic resonance spectroscopy, are reduced in patients with diabetes, heart failure and uraemia. Phosphocreatine:β adenosine triphosphate (PCr:ATP) ratio is an index of metabolic activity. We compared resting HEPs in ESRD patients and hypertensive patients (with and without LVH) who had normal renal function (LVH-only or normal myocardia). We also assessed associations of HEP levels with abnormalities of uraemic cardiomyopathy.

METHODS

Fifty-three ESRD and 30 hypertensive patients (18 with LVH, 12 with normal myocardia) underwent phosphorus magnetic resonance spectroscopy of their left ventricle. PCr:ATP ratios were calculated from (31)P-MR spectra obtained from long-axis views of the left ventricle.

RESULTS

There were no significant differences in age, LV mass, chamber sizes and ejection fraction between patient groups. PCr:ATP was significantly lower in ESRD patients compared to hypertensive patients, irrespective of the presence or absence of LVH (P = 0.01). In the ESRD group, PCr:ATP was significantly lower in patients with LVSD (P = 0.05) and LV dilation (P = 0.01). LVH was not associated with significant difference in PCr:ATP.

CONCLUSIONS

ESRD patients have lower HEP levels compared to hypertensive patients. Lower PCr:ATP ratio, indicating altered myocardial metabolic function in ESRD patients, is associated with features of uraemic cardiomyopathy.

Resting cardiac energy metabolism is inversely associated with heart rate in healthy young adult men

BACKGROUND

31-Phosphorus-magnetic resonance spectroscopy may provide pathophysiological insights into the high-energy phosphate metabolism of the myocardium as measured by phosphocreatine to adenosine triphosphate (PCr/ATP) ratio. Aim of the present study was to determine in vivo the relation between cardiac PCr/ATP ratio and heart rate in normal male subjects.

METHODS

One hundred twelve apparently healthy, young male individuals (age 34 ± 10 years) were prospectively evaluated. They underwent cardiac cine magnetic resonance imaging to assess left ventricular (LV) function and morphology and 3D-ISIS (31)P-magnetic resonance spectroscopy of the LV to assess the PCr/ATP ratio (a recognized in vivo marker of myocardial energy metabolism). Data were analyzed after segregation by tertiles of the resting PCr/ATP ratio.

RESULTS

A significant inverse association between PCr/ATP ratios and resting heart rate was observed (Spearman ρ: r=-0.37; P < .0001). PCr/ATP ratios were also inversely associated with body mass index, diastolic blood pressure, wall mass and with insulin resistance, but in multiple regression analysis heart rate was found to be independently related to PCr/ATP.

CONCLUSIONS

The present study shows that resting heart rate is proportionally lower across tertiles of increasing PCr/ATP ratio of the LV in apparently healthy young male individuals, supporting the hypothesis that heart rate is a major determinant of cardiac energy stores. These findings may explain the prognostic role of heart rate in the general population as evidenced by previous large epidemiological studies.

Left ventricular function and energy homeostasis in patients with type 1 diabetes with and without microvascular complications

BACKGROUND

This study was performed to assess left ventricular (LV) energy metabolism and function in patients with type 1 diabetes with or without overt microvascular complications.

METHODS

We performed cardiac Magnetic Resonance Imaging (MRI) and (31)P spectroscopy (MRS) in 24 patients with overt microvascular complications and in 15 carefully selected patients without complications in spite of a long duration of the disease (>20 years) and matched for anthropometric features. 31 healthy subjects served as a control group.

RESULTS

Systolic function was preserved in all study subjects. Patients with overt complications showed a higher LV wall mass/end diastolic volume ratio and altered parameters of diastolic function when compared to patients without complications and to controls. They were also characterized by lower PCr/ATP ratio (a recognized marker of energy metabolism). No effect of HbA1c was detected within groups.

CONCLUSIONS

In patients with type 1 diabetes 1) overt microvascular complications were associated with altered LV geometry, diastolic function and energy metabolism 2) in patients without complications and duration of disease >20 years no association with these alterations were found despite poor glycemic control. The features of this highly selected subgroup of patients demonstrated that long lasting chronic hyperglycemia per se is not sufficient to induce abnormality of cardiac energy metabolism and that additional yet to be identified (metabolic or genetic) factors must be important contributing factors.

Impact of pancreas transplantation on type 1 diabetes-related complications

PURPOSE OF REVIEW

Type 1 diabetes is a chronic disease that can impact patient survival and quality of life because of acute and chronic complications. Although intensive insulin scheme treatment has been shown to reduce the incidence of diabetes-related complications, only pancreas transplantation has been shown to be able to alter them and in some cases to revert them. In this review, an extensive view of the effect of pancreas transplantation on diabetes-related complication will be described.

RECENT FINDINGS

This review will focus on patients survival, diabetic nephropathy, neuropathy, cardiovascular event, comparing their incidence in type 1 diabetic patients treated with insulin and in type 1 diabetic patients receiving kidney, kidney-pancreas or pancreas alone graft. The review will focus mostly on the papers published in the last decade, with a particular attention to those on new aspects of graft function analysis like spectroscopy. Moreover, a comparison with islet transplantation procedure will be performed.

SUMMARY

This review will give an update on the potential of pancreas transplantation, give a guide for clinical practice and help to consider pancreas transplantation as an alternative to insulin treatment for selected patients.

Increased mediastinal fat and impaired left ventricular energy metabolism in young men with newly found fatty liver

Fatty liver is characterized by metabolic abnormalities at the liver, but also at skeletal muscle and adipose tissue sites. It is hypothesized that the heart may be suffering metabolic alterations, and this study was undertaken to ascertain whether individuals with fatty liver have left ventricular (LV) alterations of energy metabolism, structure, and function and abnormal amounts of epicardial fat as a specific marker of visceral fat accumulation. To this end we studied young, nondiabetic men matched for anthropometric features with (n = 21) or without (n = 21) fatty liver by means of (1) cardiac magnetic resonance imaging (MRI); (2) cardiac (31)P-MR spectroscopy (MRS); and (3) hepatic (1)H-MRS to assess quantitatively the intrahepatic fat (IHF) content. Insulin sensitivity was determined by the updated HOMA-2 computer model. Individuals with fatty liver showed reduced insulin sensitivity, increased serum free fatty acid (FFA), and E-selectin, abnormal adipokine concentrations, and higher blood pressure. LV morphology and systolic and diastolic functions were not different; however, in the scanned intrathoracic region, the intrapericardial (7.8 +/- 3.1 versus 5.9 +/- 2.5 cm(2); P < 0.05) and extrapericardial (11.7 +/- 6.1 versus 7.8 +/- 3.2 cm(2); P < 0.03) fat was increased in men with fatty liver compared with those without fatty liver. The phosphocreatine (PCr)/adenosine triphosphate (ATP) ratio, a recognized in vivo marker of myocardial energy metabolism, was reduced in men with fatty liver in comparison with normals (1.85 +/- 0.35 versus 2.11 +/- 0.31; P < 0.016). In conclusion, in newly found individuals with fatty liver, fat was accumulated in the epicardial area and despite normal LV morphological features and systolic and diastolic functions, they had abnormal LV energy metabolism.

Effect of the sporting discipline on the right and left ventricular morphology and function of elite male track runners: a magnetic resonance imaging and phosphorus 31 spectroscopy study

BACKGROUND

Professional, long-term physical training is often associated with morphological and metabolic changes in the heart. This study was undertaken to assess the left ventricular (LV) and right ventricular (RV) morphology and function and the LV high-energy phosphates of athletes trained to a sustained power or aerobic exercise.

METHODS

Magnetic resonance imaging (MRI) of the LV and RV and phosphorous 31 magnetic resonance spectroscopy of the LV were performed by means of a 1.5-T clinical scanner in 23 elite track sprinters (sustained power or anaerobic power sprint training, 100-400 m) or marathon runners (sustained aerobic endurance training) and in 10 sedentary, young, lean men.

RESULTS

Athletes had LV hypertrophy and unaffected chamber size, systolic and diastolic functions, and high-energy phosphates metabolism. Also, the RV of the athletes was hypertrophied in comparison with that of the nonathletic controls, and the systolic and diastolic functions were unaffected; the chamber volume was higher in the sprinters (end-diastolic volume 190 +/- 15 mL) in comparison with that of the marathon runners (174 +/- 19 mL, P < .05) and controls (168 +/- 19 mL, P < .01) even if this difference, when adjusted for body surface area, was maintained only when compared with that of controls (P < .02).

CONCLUSIONS

Left ventricular and RV hypertrophy in athletes is associated with normal systolic and diastolic functions and resting cardiac energy metabolism, supporting its benign nature. A more pronounced RV dilatation was found in the anaerobic power athletes and further investigation is warranted to establish the clinical significance of this training effect.

Abnormal left ventricular energy metabolism in obese men with preserved systolic and diastolic functions is associated with insulin resistance

OBJECTIVE

Perturbations in cardiac energy metabolism might represent early alterations in diabetes preceding functional and pathological changes. We evaluated left ventricular (LV) structure/geometry and function in relation to energy metabolism and cardiovascular risk factors in overweight/obese men using magnetic resonance techniques.

RESEARCH DESIGN AND METHODS

We studied 81 healthy men (aged 22-55 years, with BMI between 19 and 35 kg/m2) by means of cardiac magnetic resonance imaging and 31P-magnetic resonance spectroscopy in the resting and fasted conditions and stratified them in quartiles of BMI (cut offs: 23.2, 25.5 and 29.0 kg/m2).

RESULTS

LV mass increased across quartiles of BMI; meanwhile, the volumes did not differ. Parameters of LV systolic and diastolic function were not different among quartiles. The phosphocreatine-to-ATP ratio was reduced across increasing quartiles of mean +/- SD BMI (2.25 +/- 0.52, 1.89 +/- 0.26, 1.99 +/- 0.38, and 1.79 +/- 0.29; P < 0.006) in association with insulin sensitivity (computer homeostasis model assessment 2 model); this relation was independent of age, BMI, blood pressure, wall mass, HDL cholesterol, triglycerides, smoking habits, and metabolic syndrome.

CONCLUSIONS

Abnormal LV energy metabolism was detectable in obese men in the presence of normal function, supporting the hypothesis that metabolic remodeling in insulin resistant states precedes functional and structural/geometrical remodeling of the heart regardless of the onset of overt hyperglycemia.

Altered kidney graft high-energy phosphate metabolism in kidney-transplanted end-stage renal disease type 1 diabetic patients: a cross-sectional analysis of the effect of kidney alone and kidney-pancreas transplantation

OBJECTIVE

Diabetes, hypertension, dyslipidemia, obesity, nephrotoxicity of certain immunosuppressive drugs, and the persistence of a chronic alloimmune response may significantly affect graft survival in end-stage renal disease (ESRD) type 1 diabetic patients who have undergone kidney transplant. The aim of this study was to ascertain the impact of kidney alone (KD) or combined kidney-pancreas (KP) transplantation on renal energy metabolism.

RESEARCH DESIGN AND METHODS

We assessed high-energy phosphates (HEPs) metabolism by using, in a cross-sectional fashion, 31P-magnetic resonance spectroscopy in the graft of ESRD type 1 diabetic transplanted patients who received KD (n = 20) or KP (n = 20) transplant long before the appearance of overt chronic allograft nephropathy (CAN). Ten nondiabetic microalbuminuric kidney transplanted patients and 10 nondiabetic kidney transplanted patients with overt CAN were chosen as controls subjects.

RESULTS

Simultaneous KP transplantation patients showed a higher beta-ATP/inorganic phosphorus (Pi) ratio (marker of the graft energy status) versus the other groups, and a positive correlation between beta-ATP/Pi phosphorus ratio and A1C was found. In the analysis limited to the subgroup of normoalbuminuric patients, the difference in beta-ATP/Pi was still detectable in KP patients compared with KD transplantation.

CONCLUSIONS

KP transplantation was associated with better HEPs than in KD transplantation, suggesting that restoration of beta-cell function positively affects kidney graft metabolism.

Delayed Gadolinium-Enhanced Cardiac Magnetic Resonance in Patients With Chronic Myocarditis Presenting With Heart Failure or Recurrent Arrhythmias

OBJECTIVES

We evaluated the effectiveness of contrast-enhanced cardiac magnetic resonance (CE-CMR) in detecting chronic myocarditis (CM).

BACKGROUND

Chronic myocarditis represents a common evolution of acute myocarditis. Although CE-CMR has been revealed to be effective in identifying areas of myocardial damage in acute myocarditis, its role in the diagnosis of chronic myocardial inflammation has not yet been investigated.

METHODS

Twenty-three patients with CM underwent CE-CMR and endomyocardial biopsy (EMB). Chronic myocarditis was defined by the presence of: 1) chronic (>6 months) heart failure symptoms and/or repetitive ventricular arrhythmias; 2) no history of recent flu-like symptoms or infections; and 3) histologic evidence of active myocarditis (AM) or borderline myocarditis (BM) according to Dallas criteria. Contrast-enhanced cardiac magnetic resonance included black-blood T2-weighted (BBT2w) images without and with fat saturation and delayed three-dimensional T1 turbo field-echo inversion-recovery sequences obtained 15 min after gadolinium injection.

RESULTS

Histology showed AM in 14 patients and BM in 9 patients. FatSat BBT2w revealed the presence of edema in five (36%) patients with AM but not in BM patients. Areas of late enhancement (LE) were observed in 12 (84%) subjects with AM and in 4 (44%) cases with BM. A mid-wall LE pattern was the most frequent finding in both groups while a subepicardial distribution of LE was observed only in patients with AM.

CONCLUSIONS

Contrast-enhanced cardiac magnetic resonance identified areas of myocardial inflammation in up to 70% of patients with biopsy-proven CM. We suggest that CE-CMR may be a useful non-invasive diagnostic tool in patients with CM, and it may indicate and even guide the execution of left ventricular EMB with relevant prognostic and therapeutic implications.