Daily energy metabolism in patients with type 1 diabetes mellitus

24-h energy expenditure in people with type 1 diabetes: impact on equations for clinical estimation of energy expenditure

BACKGROUND/OBJECTIVES

Type 1 diabetes (T1D) is associated with an increase in resting metabolic rate (RMR), but the impact of T1D on other components of 24-h energy expenditure (24-h EE) is not known. Also, there is a lack of equations to estimate 24-h EE in patients with T1D. The aims of this analysis were to compare 24-h EE and its components in young adults with T1D and healthy controls across the spectrum of body mass index (BMI) and derive T1D-specific equations from clinical variables.

SUBJECTS/METHODS

Thirty-three young adults with T1D diagnosed ≥1 year prior and 33 healthy controls matched for sex, age and BMI were included in this analysis. We measured 24-h EE inside a whole room indirect calorimeter (WRIC) and body composition with dual x-ray absorptiometry.

RESULTS

Participants with T1D had significantly higher 24-h EE than healthy controls (T1D = 2047 ± 23 kcal/day vs control= 1908 ± 23 kcal/day; P < 0.01). We derived equations to estimate 24-h EE with both body composition (fat free mass + fat mass) and anthropometric (weight + height) models, which provided high coefficients of determination (R2 = 0.912 for both). A clinical model that did not incorporate spontaneous physical activity yielded high coefficients of determination as well (R2 = 0.897 and R2 = 0.880 for body composition and anthropometric models, respectively).

CONCLUSION

These results confirm that young adults with established T1D have increased 24-h EE relative to controls without T1D. The derived equations from clinically available variables can assist clinicians with energy prescriptions for weight management in patients with T1D.

Design of the advancing care for type 1 diabetes and obesity network energy metabolism and sequential multiple assignment randomized trial nutrition pilot studies: An integrated approach to develop weight management solutions for individuals with type 1 diabetes

Young adults with type 1 diabetes (T1D) often have difficulty co-managing weight and glycemia. The prevalence of overweight and obesity among individuals with T1D now parallels that of the general population and contributes to dyslipidemia, insulin resistance, and risk for cardiovascular disease. There is a compelling need to develop a program of research designed to optimize two key outcomes-weight management and glycemia-and to address the underlying metabolic processes and behavioral challenges unique to people with T1D. For an intervention addressing these dual outcomes to be effective, it must be appropriate to the unique metabolic phenotype of T1D, and to biological and behavioral responses to glycemia (including hypoglycemia) that relate to weight management. The intervention must also be safe, feasible, and accepted by young adults with T1D. In 2015, we established a consortium called ACT1ON: Advancing Care for Type 1 Diabetes and Obesity Network, a transdisciplinary team of scientists at multiple institutions. The ACT1ON consortium designed a multi-phase study which, in parallel, evaluated the mechanistic aspects of the unique metabolism and energy requirements of individuals with T1D, alongside a rigorous adaptive behavioral intervention to simultaneously facilitate weight management while optimizing glycemia. This manuscript describes the design of our integrative study-comprised of an inpatient mechanistic phase and an outpatient behavioral phase-to generate metabolic, behavioral, feasibility, and acceptability data to support a future, fully powered sequential, multiple assignment, randomized trial to evaluate the best approaches to prevent and treat obesity while co-managing glycemia in people with T1D. Clinicaltrials.gov identifiers: NCT03651622 and NCT03379792. The present study references can be found here: https://clinicaltrials.gov/ct2/show/NCT03651622 https://clinicaltrials.gov/ct2/show/NCT03379792?term=NCT03379792&draw=2&rank=1 Submission Category: "Study Design, Statistical Design, Study Protocols".

Regulatory Action of Plasma from Patients with Obesity and Diabetes towards Muscle Cells Differentiation and Bioenergetics Revealed by the C2C12 Cell Model and MicroRNA Analysis

Obesity and type 2 diabetes mellitus (T2DM) are often combined and pathologically affect many tissues due to changes in circulating bioactive molecules. In this work, we evaluated the effect of blood plasma from obese (OB) patients or from obese patients comorbid with diabetes (OBD) on skeletal muscle function and metabolic state. We employed the mouse myoblasts C2C12 differentiation model to test the regulatory effect of plasma exposure at several levels: (1) cell morphology; (2) functional activity of mitochondria; (3) expression levels of several mitochondria regulators, i.e., Atgl, Pgc1b, and miR-378a-3p. Existing databases were used to computationally predict and analyze mir-378a-3p potential targets. We show that short-term exposure to OB or OBD patients' plasma is sufficient to affect C2C12 properties. In fact, the expression of genes that regulate skeletal muscle differentiation and growth was downregulated in both OB- and OBD-treated cells, maximal mitochondrial respiration rate was downregulated in the OBD group, while in the OB group, a metabolic switch to glycolysis was detected. These alterations correlated with a decrease in ATGL and Pgc1b expression in the OB group and with an increase of miR-378a-3p levels in the OBD group.

Swimming Differentially Affects T2DM-Induced Skeletal Muscle ER Stress and Mitochondrial Dysfunction Related to MAM

PURPOSE

Mitochondrial dysfunction and endoplasmic reticulum stress (ERS) are associated with metabolic diseases such as obesity and Type 2 diabetes mellitus (T2DM). Mitochondria and ER are connected via mitochondria-associated membranes (MAM) that are involved in glucose homeostasis and insulin resistance. We postulated that exercise might positively benefit T2DM-induced ER and mitochondrial dysfunction that might be associated with MAM.

MATERIALS AND METHODS

Mice were fed a high-fat diet and injected with streptozotocin (STZ) to create T2DM models. Glucose tolerance, mitochondrial quality, MAM quality, and ERS were investigated in diabetic mice after six weeks of swimming.

RESULTS

Type 2 DM induced decreased MAM quantity, impaired mitochondrial quality, and deteriorated ERS in skeletal muscle that led to endoplasmic reticulum-associated degradation (ERAD). Swimming alleviated strong ERS caused by T2DM. Importantly, MAM quantity was positively associated with mitochondrial function and tended to negatively correlate with the ERS branch, ATF6. Moreover, both ATF6 branches of ERS and ERAD were positively associated with the pIRE1α branch of ERS.

CONCLUSION

Type 2 DM induced glucose intolerance, powerful ERS, and mitochondrial dysfunction associated with decreased amounts of MAM. Swimming improved glucose intolerance and selectively mitigated the ERS in skeletal muscle. Therefore, MAM quality and ATF6 might be novel and important targets for T2DM treatment. Endoplasmic reticulum stress might be an effective target of swimming to improve diabetes.

Obesity in Type 1 Diabetes: Pathophysiology, Clinical Impact, and Mechanisms

There has been an alarming increase in the prevalence of obesity in people with type 1 diabetes in recent years. Although obesity has long been recognized as a major risk factor for the development of type 2 diabetes and a catalyst for complications, much less is known about the role of obesity in the initiation and pathogenesis of type 1 diabetes. Emerging evidence suggests that obesity contributes to insulin resistance, dyslipidemia, and cardiometabolic complications in type 1 diabetes. Unique therapeutic strategies may be required to address these comorbidities within the context of intensive insulin therapy, which promotes weight gain. There is an urgent need for clinical guidelines for the prevention and management of obesity in type 1 diabetes. The development of these recommendations will require a transdisciplinary research strategy addressing metabolism, molecular mechanisms, lifestyle, neuropsychology, and novel therapeutics. In this review, the prevalence, clinical impact, energy balance physiology, and potential mechanisms of obesity in type 1 diabetes are described, with a special focus on the substantial gaps in knowledge in this field. Our goal is to provide a framework for the evidence base needed to develop type 1 diabetes-specific weight management recommendations that account for the competing outcomes of glycemic control and weight management.

High Fat With High Sucrose Diet Leads to Obesity and Induces Myodegeneration

Skeletal muscle utilizes both free fatty acids (FFAs) and glucose that circulate in the blood stream. When blood glucose levels acutely increase, insulin stimulates muscle glucose uptake, oxidation, and glycogen synthesis. Under these conditions, skeletal muscle preferentially oxidizes glucose while the oxidation of fatty acids (FAs) oxidation is reciprocally decreased. In metabolic disorders associated with insulin resistance, such as diabetes and obesity, both glucose uptake, and utilization muscle are significantly reduced causing FA oxidation to provide the majority of ATP for metabolic processes and contraction. Although the causes of this metabolic inflexibility or disrupted "glucose-fatty acid cycle" are largely unknown, a diet high in fat and sugar (HFS) may be a contributing factor. This metabolic inflexibility observed in models of obesity or with HFS feeding is detrimental because high rates of FA oxidation in skeletal muscle can lead to the buildup of toxic metabolites of fat metabolism and the accumulation of pro-inflammatory cytokines, which further exacerbate the insulin resistance. Further, HFS leads to skeletal muscle atrophy with a decrease in myofibrillar proteins and phenotypically characterized by loss of muscle mass and strength. Overactivation of ubiquitin proteasome pathway, oxidative stress, myonuclear apoptosis, and mitochondrial dysfunction are some of the mechanisms involved in muscle atrophy induced by obesity or in mice fed with HFS. In this review, we will discuss how HFS diet negatively impacts the various physiological and metabolic mechanisms in skeletal muscle.

Diabetes-Induced Dysfunction of Mitochondria and Stem Cells in Skeletal Muscle and the Nervous System

Diabetes mellitus is one of the most common metabolic diseases spread all over the world, which results in hyperglycemia caused by the breakdown of insulin secretion or insulin action or both. Diabetes has been reported to disrupt the functions and dynamics of mitochondria, which play a fundamental role in regulating metabolic pathways and are crucial to maintain appropriate energy balance. Similar to mitochondria, the functions and the abilities of stem cells are attenuated under diabetic condition in several tissues. In recent years, several studies have suggested that the regulation of mitochondria functions and dynamics is critical for the precise differentiation of stem cells. Importantly, physical exercise is very useful for preventing the diabetic alteration by improving the functions of both mitochondria and stem cells. In the present review, we provide an overview of the diabetic alterations of mitochondria and stem cells and the preventive effects of physical exercise on diabetes, focused on skeletal muscle and the nervous system. We propose physical exercise as a countermeasure for the dysfunction of mitochondria and stem cells in several target tissues under diabetes complication and to improve the physiological function of patients with diabetes, resulting in their quality of life being maintained.

Treadmill running induces satellite cell activation in diabetic mice

Skeletal muscle-derived stem cells, termed as satellite cells, play essential roles in regeneration after muscle injury in adult skeletal muscle. Diabetes mellitus (DM), one of the most common metabolic diseases, causes impairments of satellite cell function. However, the studies of the countermeasures for the DM-induced dysfunction of satellite cells have been poor. Here, we investigated the effects of chronic running exercise on satellite cell activation in diabetic mice focused on the molecular mechanism including Notch and Wnt signaling, which are contribute to the fate determination of satellite cells. Male C57BL/6 mice 4 weeks of age were injected with streptozotocin and were randomly divided into runner group and control group. Runner group mice were performed treadmill running for 4 weeks. DM attenuated satellite cell activation and the expressions of the components of Notch and Wnt signaling. However, chronic running resulted in activation of satellite cells in diabetic mice and salvaged the inactivity of Wnt signaling but not Notch signaling. Our results suggest that chronic running induces satellite cell activation via upregulation of Wnt signaling in diabetic as well as normal mice.

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Diabetes attenuates satellite cell activation.

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Diabetes downregulates the activities of Notch and Wnt signaling.

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Treadmill running activates satellite cells in diabetic mice.

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Treadmill running can salvage diabetes-induced downregulation of Wnt signaling.

Diabetes and stem cell function

Diabetes mellitus is one of the most common serious metabolic diseases that results in hyperglycemia due to defects of insulin secretion or insulin action or both. The present review focuses on the alterations to the diabetic neuronal tissues and skeletal muscle, including stem cells in both tissues, and the preventive effects of physical activity on diabetes. Diabetes is associated with various nervous disorders, such as cognitive deficits, depression, and Alzheimer's disease, and that may be caused by neural stem cell dysfunction. Additionally, diabetes induces skeletal muscle atrophy, the impairment of energy metabolism, and muscle weakness. Similar to neural stem cells, the proliferation and differentiation are attenuated in skeletal muscle stem cells, termed satellite cells. However, physical activity is very useful for preventing the diabetic alteration to the neuronal tissues and skeletal muscle. Physical activity improves neurogenic capacity of neural stem cells and the proliferative and differentiative abilities of satellite cells. The present review proposes physical activity as a useful measure for the patients in diabetes to improve the physiological functions and to maintain their quality of life. It further discusses the use of stem cell-based approaches in the context of diabetes treatment.

Restoration of adiponectin pulsatility in severely obese subjects after weight loss

Diurnal variations of adiponectin levels have been studied in normal-weight men and in diabetic and nondiabetic obese subjects, but no data have been reported in obese subjects after weight loss. We collected blood samples at 1-h intervals over 24 h from seven severely obese subjects before and after massive weight loss consequent to surgical operation (bilio-pancreatic diversion [BPD]) to measure adiponectin, insulin, glucose, and cortisol levels. Insulin sensitivity was assessed by euglycemic-hyperinsulinemic clamp (M value). Studies of diurnal variations and pulsatility of adiponectin, insulin, and cortisol were performed. The pulsatility index (PI) of adiponectin increased after BPD from 0.04 to 0.11 microg/min (P = 0.01). Insulin PI significantly increased after the operation (1.50 vs. 1.08 pmol.l(-1).min(-1), P = 0.01), while cortisol PI did not significantly change. The adiponectin clearance rate changed from 0.001 +/- 10(-4).min(-1) before BPD to 0.004 +/- 8. 10(-4).min(-1) after BPD (P = 0.03). Insulin clearance increased from 0.006 +/- 6. 10(-4).min(-1) before BPD to 0.009 +/- 4.10(-4). min(-1) after BPD (P = 0.02). The M value doubled after surgery (27.08 +/- 8.5 vs. 53.34 +/- 9.3 micromol.kg(FFM)(-1).min(-1); P < 0.001) becoming similar to the values currently reported for normal-weight subjects. In conclusion, in formerly severely obese subjects, weight loss paired with the reversibility of insulin resistance restores homeostatic control of the adiponectin secretion, contributing to the reduction of cardiovascular risk already described in these patients.

Decreased uncoupling protein expression and intramyocytic triglyceride depletion in formerly obese subjects

OBJECTIVE

To examine the muscular uncoupling protein expression 2 (UCP2) and UCP3 gene expression in morbid obese subjects before and after bariatric surgery [bilio-pancreatic diversion (BPD)].

RESEARCH METHODS AND PROCEDURES

Eleven obese subjects (BMI = 49 +/- 2 kg/m(2)) were studied before BPD and 24 months after BPD. Skeletal muscle UCP2 and UCP3 mRNA was measured using reverse transcriptase-competitive polymerase chain reaction and UCP3 protein by Western blotting. Intramyocytic triglycerides were quantified by high-performance liquid chromatography. Twenty-four-hour energy expenditure and respiratory quotient (RQ) were measured in a respiratory chamber.

RESULTS

After BPD, the average weight loss was approximately 38%. Nonprotein RQ was increased in the postobese subjects (0.73 +/- 0.00 vs. 0.83 +/- 0.02, p < 0.001). The intramyocytic triglyceride level dropped (3.66 +/- 0.16 to 1.60 +/- 0.29 mg/100 mg of fresh tissue, p < 0.0001) after BPD. Expression of UCP2 and UCP3 mRNA was significantly reduced (from 35.9 +/- 6.1% to 18.6 +/- 4.5% of cyclophilin, p = 0.02; from 60.2 +/- 14.0% to 33.4 +/- 8.5%, p = 0.03; respectively). UCP3 protein content was also significantly reduced (272.19 +/- 84.13 vs. 175.78 +/- 60.31, AU, p = 0.04). A multiple regression analysis (R(2) = 0.90) showed that IMTG levels (p = 0.007) represented the most powerful independent variable for predicting UCP3 variation.

DISCUSSION

The strong correlation of UCP expression and decrease in IMTG levels suggests that triglyceride content plays an even more important role in the regulation of UCP gene expression than the circulating levels of free fatty acids or the achieved degree of weight loss.

Computing DIT from energy expenditure measures in a respiratory chamber: a direct modeling method

The possibility of computing Diet Induced Thermogenesis (DIT) is an important feature of metabolic investigations. However, methodological problems have affected the determination of DIT in the indirect calorimetric chamber. DIT has been commonly estimated by regressing energy expenditure on a measure of physical activity. Although used for many years as the only feasible approach to calculate DIT in a respiratory chamber, this traditional method has been criticized because of an apparent underestimation of the DIT, but no alternative method has been suggested so far. The present work proposes to estimate DIT directly by means of a mathematical model. This approach also allows to simultaneously estimate other parameters, namely resting energy expenditure (REE), physical activity (PA) and physical exercise (PE).

Daily energy and substrate metabolism in patients with cirrhosis

Twenty-four-hour energy expenditure (EE) and substrate oxidation (respiratory chamber), and whole-body glucose uptake and oxidation rates (euglycemic hyperinsulinemic clamp [EHC] and indirect calorimetry) were measured in 10 male patients with posthepatitis, Child B cirrhosis, and 8 healthy male controls matched for age, body size, and body composition. Twenty-four-hour EE was higher in cirrhotic patients than in controls (8,567 +/- 764 vs. 6,825 +/- 507 kJ/d; P < .001). Resting energy expenditure (REE) was also higher in cirrhotic patients than in controls (7,881 +/- 1,125 vs. 5,868 +/- 489 kJ/d; P < .01). Twenty-four-hour respiratory quotient (RQ) (trend) and fasting RQ (0.76 +/- 0.05 vs. 0.82 +/- 0.04; P < .05) were lower in cirrhotic patients than in controls, reflecting higher lipid oxidation rates in the former group. Whole-body glucose uptake was markedly reduced in cirrhotic patients when compared with controls (22.4 +/- 3.2 vs. 44.5 +/- 7.6 mmol/kg/min; P < .001). Carbohydrate oxidation rates, computed during the last 40 minutes of the clamp, were 8.5 +/- 1.1 mmol/kg/min in cirrhotic patients and 22.6 +/- 6.1 mmol/kg/min in controls (P < .001). Nonoxidative glucose disposal was 13.9 +/- 2.5 mmol/kg/min in cirrhotic patients and 22.0 +/- 5.5 mmol/kg/min in normal controls (P < .01). In conclusion, our data indicate that patients with Child B cirrhosis who still maintain a nutritional status (i.e., body composition) comparable with healthy controls are characterized by a cluster of metabolic defects that include hypermetabolism, increased lipid utilization, and insulin resistance. This suggests that the above metabolic syndrome precedes and probably leads to malnutrition in the natural history of the liver disease. In fact, in spite of the absence of a significant difference in caloric intake between cirrhotic patients and normal controls, the elevated 24-hour EE might allow for a relevant weight loss in cirrhotic patients, because, with time, the differences may be cumulative. However, whether this hypermetabolism can lead to a real weight loss remains to be evaluated in a longitudinal study.