Chronic peripheral hyperinsulinemia in type 1 diabetic patients after successful combined pancreas-kidney transplantation does not affect ectopic lipid accumulation in skeletal muscle and liver

Intramyocellular Triglyceride Content During the Early Course of Type 1 and Type 2 Diabetes

Intramyocellular lipid content (IMCL) is elevated in insulin-resistant humans, but it changes over time, and relationships with comorbidities remain unclear. We examined IMCL during the initial course of diabetes and its associations with complications. Participants of the German Diabetes Study (GDS) with recent-onset type 1 (n = 132) or type 2 diabetes (n = 139) and glucose-tolerant control subjects (n = 128) underwent 1H-MRS to measure IMCL and muscle volume, whole-body insulin sensitivity (hyperinsulinemic-euglycemic clamps; M-value), and cycling spiroergometry (VO2max). Subgroups underwent the same measurements after 5 years. At baseline, IMCL was ∼30% higher in type 2 diabetes than in other groups independently of age, sex, BMI, and muscle volume. In type 2 diabetes, the M-value was ∼36% and ∼62% lower compared with type 1 diabetes and control subjects, respectively. After 5 years, the M-value decreased by ∼29% in type 1 and ∼13% in type 2 diabetes, whereas IMCL remained unchanged. The correlation between IMCL and M-value in type 2 diabetes at baseline was modulated by VO2max. IMCL also associated with microalbuminuria, the Framingham risk score for cardiovascular disease, and cardiac autonomic neuropathy. Changes in IMCL within 5 years after diagnosis do not mirror the progression of insulin resistance in type 2 diabetes but associate with early diabetes-related complications.

ARTICLE HIGHLIGHTS

Intramyocellular lipid content (IMCL) can be elevated in insulin-resistant humans, but its dynamics and association with comorbidities remain unclear. Independently of age, sex, body mass, and skeletal muscle volume, IMCL is higher in recent-onset type 2, but not type 1 diabetes, and remains unchanged within 5 years, despite worsening insulin resistance. A degree of physical fitness modulates the association between IMCL and insulin sensitivity in type 2 diabetes. Whereas higher IMCL associates with lower insulin sensitivity in people with lower physical fitness, there is no association between IMCL and insulin sensitivity in those with higher degree of physical fitness. IMCL associates with progression of microalbuminuria, cardiovascular disease risk, and cardiac autonomic neuropathy.

Insulin pump therapy in type 1 diabetes is associated with lower indices of Non-Alcoholic Fatty Liver in non-obese women but not men

AIM

Non-Alcoholic Fatty Liver Disease (NAFLD) is a raising concern in type 1 diabetes (T1D) patients. We evaluated whether multiple daily injections (MDI) or continuous subcutaneous insulin infusion (CSII) may differentially affect NAFLD.

METHODS

NAFLD was assessed by Fatty Liver Index (FLI) and Hepatic Steatosis Index (HSI) in 659 T1D patients treated by MDI (n=414, 65% men) or CSII (n=245, 50% men) without alcohol abuse or other liver diseases. Clinical and metabolic differences between MDI and CSII participants were also evaluated according to sex.

RESULTS

Compared with the MDI cohort, CSII users had a significantly lower FLI (20.2±21.2 vs. 24.8±24.3; p=0.003), HSI (36.2±4.4 vs. 37.4±4.4; p=0.003), waist circumference (84.6±11.8 vs. 86.9±13.7 cm; p=0.026), plasma triglyceride (76.0±45.8 vs. 84.7±58.3 mg/dl; p=0.035), and daily insulin dose (0.53±0.22 vs. 0.64±0.25 IU/kg body weight; p<0.001). In CSII users, lower FLI and HSI were observed in women (p=0.009 and p=0.033, respectively) but not in men (p=0.676 and p=0.131, respectively). Women on CSII also had lower daily insulin doses, plasma triglyceride, and visceral adiposity index than women on MDI.

CONCLUSION

CSII is associated with lower NAFLD indices in women with T1D. This may relate to the lower peripheral insulin in the context of a permissive hormonal milieu.

Application of Nanoparticles: Diagnosis, Therapeutics, and Delivery of Insulin/Anti-Diabetic Drugs to Enhance the Therapeutic Efficacy of Diabetes Mellitus

Diabetes mellitus (DM) is a chronic metabolic disorder of carbohydrates, lipids, and proteins due to a deficiency of insulin secretion or failure to respond to insulin secreted from pancreatic cells, which leads to high blood glucose levels. DM is one of the top four noncommunicable diseases and causes of death worldwide. Even though great achievements were made in the management and treatment of DM, there are still certain limitations, mainly related to the early diagnosis, and lack of appropriate delivery of insulin and other anti-diabetic agents. Nanotechnology is an emerging field in the area of nanomedicine and NP based anti-diabetic agent delivery is reported to enhance efficacy by increasing bioavailability and target site accumulation. Moreover, theranostic NPs can be used as diagnostic tools for the early detection and prevention of diseases owing to their unique biological, physiochemical, and magnetic properties. NPs have been synthesized from a variety of organic and inorganic materials including polysaccharides, dendrimers, proteins, lipids, DNA, carbon nanotubes, quantum dots, and mesoporous materials within the nanoscale size. This review focuses on the role of NPs, derived from organic and inorganic materials, in the diagnosis and treatment of DM.

When Sugar Reaches the Liver: Phenotypes of Patients with Diabetes and NAFLD

Type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD) have been traditionally linked to one another. Recent studies suggest that NAFLD may be increasingly common in other types of diabetes such as type 1 diabetes (T1DM) and less frequently ketone-prone and Maturity-onset Diabetes of the Young (MODY) diabetes. In this review, we address the relationship between hyperglycemia and insulin resistance and the onset and progression of NAFLD. In addition, despite the high rate of patients with T2DM and other diabetes phenotypes that can alter liver metabolism and consequently develop steatosis, fibrosis, and cirrhosis, NALFD screening is not still implemented in the daily care routine. Incorporating a clinical algorithm created around a simple, non-invasive, cost-effective model would identify high-risk patients. The principle behind managing these patients is to improve insulin resistance and hyperglycemia states with lifestyle changes, weight loss, and new drug therapies.

Hepatopathy Associated With Type 1 Diabetes: Distinguishing Non-alcoholic Fatty Liver Disease From Glycogenic Hepatopathy

Autoimmune destruction of pancreatic β-cells results in the permanent loss of insulin production in type 1 diabetes (T1D). The daily necessity to inject exogenous insulin to treat hyperglycemia leads to a relative portal vein insulin deficiency and potentiates hypoglycemia which can induce weight gain, while daily fluctuations of blood sugar levels affect the hepatic glycogen storage and overall metabolic control. These, among others, fundamental characteristics of T1D are associated with the development of two distinct, but in part clinically similar hepatopathies, namely non-alcoholic fatty liver disease (NAFLD) and glycogen hepatopathy (GlyH). Recent studies suggest that NAFLD may be increasingly common in T1D because more people with T1D present with overweight and/or obesity, linked to the metabolic syndrome. GlyH is a rare but underdiagnosed complication hallmarked by extremely brittle metabolic control in, often young, individuals with T1D. Both hepatopathies share clinical similarities, troubling both diagnosis and differentiation. Since NAFLD is increasingly associated with cardiovascular and chronic kidney disease, whereas GlyH is considered self-limiting, awareness and differentiation between both condition is important in clinical care. The exact pathogenesis of both hepatopathies remains obscure, hence licensed pharmaceutical therapy is lacking and general awareness amongst physicians is low. This article aims to review the factors potentially contributing to fatty liver disease or glycogen storage disruption in T1D. It ends with a proposal for clinicians to approach patients with T1D and potential hepatopathy.

Prevalence of Nonalcoholic Fatty Liver Disease (NAFLD) in Patients With Type 1 Diabetes Mellitus: A Systematic Review and Meta-Analysis

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) prevalence is high, especially in patients with obesity and type 2 diabetes, and is expected to rise steeply in the coming decades.

OBJECTIVE

We estimated NAFLD prevalence in patients with type 1 diabetes and explored associated characteristics and outcomes.

DATA SOURCES

We reviewed PubMed and Embase for studies on NAFLD and type 1 diabetes to March 2020. We screened references of included articles.

STUDY SELECTION

Two authors independently screened titles/abstracts. One author screened full text articles. NAFLD was defined as described in the individual studies: steatosis and/or fibrosis. Studies not reporting alternative causes of hepatic steatosis or defining NAFLD only as elevated liver enzymes, were excluded. Initially, 919 articles met the selection criteria.

DATA EXTRACTION

One researcher performed data extraction and risk of bias assessment using standardized tables.

DATA SYNTHESIS

We assessed pooled prevalence rates by meta-analysis using a random-effects model, subsequently exploring heterogeneity by subgroup-, meta-regression-, and sensitivity analysis. Twenty studies between 2009 and 2019 were included (n = 3901). Pooled NAFLD prevalence was 19.3% (95% CI, 12.3%-27.5%), increasing to 22.0% (95% CI, 13.9%-31.2%) in adults only. Pooled prevalence of ultrasound studies was high (27.1%, 95% CI, 18.7%-36.3%) compared to studies using magnetic resonance imaging (8.6%, 95% CI, 2.1%-18.6%), liver biopsy (19.3%, 95% CI, 10.0%-30.7%), or transient elastography (2.3%, 95% CI, 0.6%-4.8%).

CONCLUSION

NAFLD prevalence in patients with type 1 diabetes is considerable and is highly dependent on the specific diagnostic modality and NAFLD definition used. These data are helpful in directing actions to standardize NAFLD diagnosis, which will help defining contributing mechanisms and outcomes.

Accumulation of advanced glycation end products in the skin is accelerated in relation to insulin resistance in people with Type 1 diabetes mellitus

AIM

To evaluate the association between skin advanced glycation end products and insulin resistance in Type 1 diabetes.

METHODS

The study group consisted of 476 people with Type 1 diabetes (247 men) with a median (interquartile range) age of 42 (33-53) years, disease duration of 24 (19-32) years and HbA_1c concentration of 63 (55-74) mmol/mol [7.9 (7.2-8.9)%]. Insulin resistance was assessed according to estimated glucose disposal rate. Advanced glycation product accumulation in the skin was measured by autofluorescence using an AGE Reader. The group was divided into three subgroups based on estimated glucose disposal rate tertiles (<5.5, 5.5-9.5 and >9.5 mg/kg/min, respectively). The higher the estimated glucose disposal rate, the lower the insulin resistance.

RESULTS

Skin autofluoresence level decreased with increasing estimated glucose disposal rate; comparing people below the lower tertile, with those between the first and third tertiles, and with those above the third tertile, the median autofluoresences were, respectively: 2.5 (2.2-2.9) vs 2.3 (2.0-2.7) vs 2.1 (1.9-2.5) AU (P<0.0001). A negative correlation was observed between skin autofluorescence and estimated glucose disposal rate (Spearman's correlation coefficient=-0.31, P <0.001). Multiple logistic regression showed a significant, two-way association of insulin resistance with skin autofluorescence.

CONCLUSION

The results of this study offer strong evidence for a two-way relationship between insulin resistance and advanced glycation product accumulation in the skin in people with Type 1 diabetes.

Insulin resistance in type 1 diabetes mellitus

For long the presence of insulin resistance in type 1 diabetes has been questioned. Detailed metabolic analyses revealed 12%-61% and up to 20% lower whole-body (skeletal muscle) and hepatic insulin sensitivity in type 1 diabetes, depending on the population studied. Type 1 diabetes patients feature impaired muscle adenosine triphosphate (ATP) synthesis and enhanced oxidative stress, predominantly relating to hyperglycemia. They may also exhibit abnormal fasting and postprandial glycogen metabolism in liver, while the role of hepatic energy metabolism for insulin resistance remains uncertain. Recent rodent studies point to tissue-specific differences in the mechanisms underlying insulin resistance. In non-obese diabetic mice, increased lipid availability contributes to muscle insulin resistance via diacylglycerol/protein kinase C isoforms. Furthermore, humans with type 1 diabetes respond to lifestyle modifications or metformin by 20%-60% increased whole-body insulin sensitivity, likely through improvement in both glycemic control and oxidative phosphorylation. Intensive insulin treatment and islet transplantation also increase but fail to completely restore whole-body and hepatic insulin sensitivity. In conclusion, insulin resistance is a feature of type 1 diabetes, but more controlled trials are needed to address its contribution to disease progression, which might help to optimize treatment and reduce comorbidities.

A comparison of long-term outcomes of portal versus systemic venous drainage in pancreatic transplantation: a systematic review and meta-analysis

Pancreas transplantation venous effluent can be drained via the portal vein or the systemic circulation; however, no recommendation exists for the ideal technique. A systematic review of the literature from 1989 through 2014 using PubMed, CINHAL, and Cochrane Library for portal versus systemic venous drainage was undertaken. Only studies on humans and published in English were considered. Measures of glycemic control and total cholesterol were synthesized for meta-analysis utilizing random-effects models. Of 166 articles retrieved, 15 articles were included for meta-analysis. Patient and graft survival were comparable in a large database study as well as in the only randomized control study. No differences in complications were seen when exocrine drainage was enteric for the systemic venous group. Fasting insulin (-34.13 pmol/mL, p < 0.001) was significantly lower within the portal drained group; however, fasting blood glucose levels (-3.4 mg/dL, p = 0.32) and hemoglobin A1C levels (mean difference 0.124%, p = 0.25) were comparable. Total cholesterol levels (-3.62 mg/dL, p = 0.447), as well as other measures of lipids, showed no difference. Based on this systematic review and meta-analysis, there is no evidence of differences in outcomes or metabolic control in patients undergoing pancreatic transplant with portal venous drainage compared to the systemic venous drainage.

Whole-body insulin sensitivity rather than body-mass-index determines fasting and post-glucose-load growth hormone concentrations

Background

Obese, non-acromegalic persons show lower growth hormone (GH) concentrations at fasting and reduced GH nadir during an oral glucose tolerance test (OGTT). However, this finding has never been studied with regard to whole-body insulin-sensitivity as a possible regulator.

Methods

In this retrospective analysis, non-acromegalic (NonACRO, n = 161) and acromegalic (ACRO, n = 35), non-diabetic subjects were subdivided into insulin-sensitive (IS) and –resistant (IR) groups according to the Clamp-like Index (CLIX)-threshold of 5 mg·kg⁻¹·min⁻¹ from the OGTT.

Results

Non-acromegalic IS (CLIX: 8.8±0.4 mg·kg⁻¹·min⁻¹) persons with similar age and sex distribution, but lower (p<0.001) body-mass-index (BMI = 25±0 kg/m², 84% females, 56±1 years) had 59% and 70%, respectively, higher (p<0.03) fasting GH and OGTT GH area under the curve concentrations than IR (CLIX: 3.5±0.1 mg·kg⁻¹·min⁻¹, p<0.001) subjects (BMI = 29±1 kg/m², 73% females, 58±1 years). When comparing on average overweight non-acromegalic IS and IR with similar anthropometry (IS: BMI: 27±0 kg/m², 82% females, 58±2 years; IR: BMI: 27±0 kg/m², 71% females, 60±1 years), but different CLIX (IS: 8.7±0.9 vs. IR: 3.8±0.1 mg·kg⁻¹·min⁻¹, p<0.001), the results remained almost the same. In addition, when adjusted for OGTT-mediated glucose rise, GH fall was less pronounced in IR. In contrast, in acromegalic subjects, no difference was found between IS and IR patients with regard to fasting and post-glucose-load GH concentrations.

Conclusions

Circulating GH concentrations at fasting and during the OGTT are lower in non-acromegalic insulin-resistant subjects. This study seems the first to demonstrate that insulin sensitivity rather than body-mass modulates fasting and post-glucose-load GH concentrations in non-diabetic non–acromegalic subjects.

Pancreas transplantation: a treatment option for people with diabetes

Since the first pancreas transplants in the early 1960s, whole-organ pancreas transplantation, either alone or combined with kidney transplantation, has become commonplace in many countries around the world. Whole-organ pancreas transplantation is available in the UK, with ~200 transplants currently carried out per year. Patient survival and pancreas graft outcome rates are now similar to other solid organ transplant programmes, with high rates of long-term insulin independence. In the present review, we will discuss whole-pancreas transplantation as a treatment for diabetes, focusing on indications for transplantation, the nature of the procedure performed, graft survival rates and the consequences of pancreas transplantation on metabolic variables and the progression of diabetes-related complications.

Fasting and postprandial liver glycogen content in patients with type 1 diabetes mellitus after successful pancreas-kidney transplantation with systemic venous insulin delivery

BACKGROUND

In patients with type 1 diabetes mellitus (T1DM), insulin is usually replaced systemically (subcutaneously) and not via the physiological portal route. According to previous studies, the liver's capacity to store glycogen is reduced in T1DM patients, but it remains unclear whether this is due to hyperglycaemia, or whether the route of insulin supply could contribute to this phenomenon. T1DM patients after successful pancreas-kidney transplantation with systemic venous drainage (T1DM-PKT) represent a suitable human model to further investigate this question, because they are normoglycaemic, but their liver receives insulin from the pancreas transplant via the systemic route.

MATERIALS AND METHODS

In nine T1DM-PKT, nine controls without diabetes (CON) and seven patients with T1DM (T1DM), liver glycogen content was measured at fasting and after two standardized meals employing (13) C-nuclear-magnetic-resonance-spectroscopy. Circulating glucose and glucoregulatory hormones were measured repeatedly throughout the study day.

RESULTS

The mean and fasting concentrations of peripheral plasma glucose, insulin, glucagon and C-peptide were comparable between T1DM-PKT and CON, whereas T1DM were hyperglycaemic and hyperinsulinaemic (P < 0·05 vs T1DM-PKT and CON). Total liver glycogen content at fasting and after breakfast did not differ in the three groups. After lunch, T1DM-PKT and T1DM had a 14% and 21% lower total liver glycogen content than CON (P < 0·02).

CONCLUSION

In spite of normalized glycaemic control, postprandial liver glycogen content was reduced in T1DM-PKT with systemic venous drainage. Thus, not even optimized systemic insulin substitution is able to resolve the defect in postprandial liver glycogen storage seen in T1DM patients.

Examination of carbohydrate metabolism parameters after simultaneous pancreas-kidney transplantation

End-stage renal failure, a frequent complication of type 1 diabetes mellitus, requires renal replacement therapy. Our team examined the laboratory parameters of carbohydrate metabolism in 18 patients with type 1 diabetes at 10 to 89 months after simultaneous pancreas-kidney transplantation. We compared these results with those of 17 patients with type 1 diabetes who had formerly received kidney-alone transplantations, and were undergoing insulin treatment, as well as with those of 16 metabolically healthy controls. The hemoglobin A1c (HbA1c) and blood glucose levels of the pancreas-kidney transplant recipients were within the normal ranges, not differing significantly from those of the healthy controls. In contrast, the HbA1c and glucose levels were significantly elevated among kidney transplanted diabetic subjects. However, fasting and 2-hour insulin levels of pancreas-kidney transplant patients were significantly higher than those of the controls, indicating insulin resistance. According to these results, the insulin secretion by the pancreas graft sufficiently compensated for insulin resistance. Thus 10 to 89 months after successful pancreas-kidney transplantation, carbohydrate metabolism by type 1 diabetic patients was well controlled without antidiabetic therapy.

Effects of pioglitazone versus glimepiride exposure on hepatocellular fat content in type 2 diabetes

AIMS

Thiazoledinediones decrease blood glucose by their insulin-sensitizing properties. Here, we examined whether pioglitazone plus nateglinide (PIO) interferes with hepatocellular lipid (HCL) content and/or improves insulin sensitivity in well-controlled non-obese patients with type 2 diabetes mellitus (T2DM).

METHODS

Sixteen patients [body mass index (BMI): 28 ± 1 kg/m(2) ; HbA1c: 7.1 ± 0.6%] were studied in a randomized, double-blind, 12-week parallel group trial, whereas matched healthy humans [non-diabetic control subjects (CON), BMI: 26 ± 1 kg/m(2)] were studied once. Treatment with pioglitazone (30 mg/day) plus nateglinide (PIO arm) to control for glimepiride-induced insulin secretion was compared to treatment with glimepiride (2 mg/day) plus placebo (GLI arm). Multinuclei magnetic resonance spectroscopy (MRS) was combined with pancreatic normoglycaemic-two-step-insulin clamps and stable isotopes to assess glucose turnover, glucose transport/phosphorylation, HCL and intramyocellular lipid (IMCL) contents, non-esterified fatty acids (NEFA) and adipokines.

RESULTS

At baseline, HCL was approximately 5.6-fold higher in T2DM (p < 0.05 vs. CON). This was paralleled by approximately doubled leptin : adiponectin ratios (p < 0.05). HCL decreased by approximately 39% (p < 0.05) after PIO and only tended to decrease after GLI (p = 0.12). Treatment with PIO did not affect leptin : adiponectin ratios, but slightly improved (p < 0.05) insulin-mediated NEFA suppression, which related to lower HCL. PIO further prevented the insulin-induced increase in IMCL content of soleus and tibialis anterior muscles. Peripheral and hepatic insulin sensitivity, glucose transport and glycaemic control did not change in both groups.

CONCLUSION

Short-term, low-dose thiazolidendione treatment improves insulin sensitivity of lipolysis and HCL, without affecting muscle and liver insulin sensitivity. It appears that metabolic PIO action in T2DM is primarily mediated via a decline in HCL associated with greater sensitivity of lipolysis to insulin.

Glucose absorption in gestational diabetes mellitus during an oral glucose tolerance test

OBJECTIVE

Women with gestational diabetes mellitus (GDM) show reduced insulin sensitivity and markedly elevated glucose excursions. After delivery, GDM mostly reverts to normal glucose tolerance (NGT), although leaving an increased risk of type 2 diabetes. Because gastrointestinal function changes during pregnancy causing vomiting, constipation, or reduced motility, we thought that gut glucose absorption in GDM or pregnancy might be altered to affect circulating glucose excursions.

RESEARCH DESIGN AND METHODS

By undergoing 180-min oral glucose tolerance tests (OGTTs), pregnant women with GDM (GDMpreg; n=15, BMI=32±2 kg/m2, aged 33±1 years) were compared with NGT women (NGTpreg; n=7, BMI=28±1 kg/m2, aged 34±2 years), matching for major anthropometric characteristics (each P>0.2). After delivery (6-7 months later), both groups were studied the same way. We computed and mathematically modeled gut glucose absorption from insulin-mediated glucose disappearance and endogenous glucose production (EGP). Whole-body insulin sensitivity was calculated using the Clamp-like Index.

RESULTS

GDMpreg showed 16-25% higher plasma glucose concentrations (P<0.04) during the final 2 h of OGTT, similar EGP, but lower (P<0.01) insulin sensitivity (2.7±0.2 mg·kg(-1)·min(-1) vs. NGTpreg: 4.5±0.8 mg·kg(-1)·min(-1)). In GDMpreg, gut glucose absorption rates were ≤52% lower from 30 to 120 min (P<0.03 vs. conditions after delivery or NGTpreg). In contrast, glucose absorption rates in NGTpreg were comparable during and after pregnancy. None of the studied women developed diabetes after delivery.

CONCLUSIONS

In GDMpreg, OGTT gut glucose absorption is markedly lower during hyperglycemia, whereas both glycemia and glucose absorption in NGTpreg are comparable between pregnant and postpartum states. Thus, hyperglycemia in GDM does not seem to result from too rapid or increased glucose absorption.

Current status of pancreas transplantation

Pancreas transplantation has emerged as the treatment of choice for patients with end-stage diabetes mellitus. Over the last four decades, many improvements have been made in the surgical techniques and immunosuppressive regimens, which contributed to increased number of indications and improved allograft survival. Pancreas transplantation can be justified on the basis that patients replace daily injections of insulin with an improved quality of life but at the expense of a major surgical procedure with a relatively higher complication rate, and lifelong immunosuppression. Therefore, efforts to develop more minimally invasive techniques for endocrine replacement therapy such as islet transplantation have been in progress. This article summarizes the current understanding of pancreas transplantation-associated indications, donor selection, surgical techniques, immunosuppression, and rejection.