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Endocrine Jul 2023Secondary diabetes mellitus (DM) is a common complication of acromegaly, encountered in up to 55% of cases. Vice versa, the prevalence of acromegaly is markedly higher... (Review)
Review
Secondary diabetes mellitus (DM) is a common complication of acromegaly, encountered in up to 55% of cases. Vice versa, the prevalence of acromegaly is markedly higher in cohorts of patients with type 2 DM (T2DM). The presence of secondary DM depends primarily on acromegaly status and is associated with increased cardiovascular morbidity, malignancy rate and overall mortality. The principal pathophysiologic mechanism is increased insulin resistance due to excessive lipolysis and altered fat distribution, reflected at the presence of intermuscular fat and attenuated, dysfunctional adipose tissue. Insulin resistance is ascribed to the direct, diabetogenic effects of growth hormone (GH), which prevail over the insulin-sensitizing effects of insulin-like growth factor 1 (IGF-1), probably due to higher glucometabolic potency of GH, IGF-1 resistance, or both. Inversely, GH and IGF-1 act synergistically in increasing insulin secretion. Hyperinsulinemia in portal vein leads to enhanced responsiveness of liver GH receptors and IGF-1 production, pointing towards a mutually amplifying loop between GH-IGF-1 axis and insulin. Secondary DM occurs upon beta cell exhaustion, principally due to gluco-lipo-toxicity. Somatostatin analogues inhibit insulin secretion; especially pasireotide (PASI) impairs glycaemic profile in up to 75% of cases, establishing a separate pathophysiologic entity, PASI-induced DM. In contrast, pegvisomant and dopamine agonizts improve insulin sensitivity. In turn, metformin, pioglitazone and sodium-glucose transporters 2 inhibitors might be disease-modifying by counteracting hyperinsulinemia or acting pleiotropically. Large, prospective cohort studies are needed to validate the above notions and define optimal DM management in acromegaly.
Topics: Humans; Acromegaly; Insulin-Like Growth Factor I; Insulin Resistance; Prospective Studies; Human Growth Hormone; Growth Hormone; Insulin; Diabetes Mellitus
PubMed: 36882643
DOI: 10.1007/s12020-023-03339-1 -
Biomolecules Jan 2024Since the first discovery in 1989, the β3-adrenoceptor (β3-AR) has gained great attention because it showed the ability to regulate many physiologic and metabolic... (Review)
Review
Since the first discovery in 1989, the β3-adrenoceptor (β3-AR) has gained great attention because it showed the ability to regulate many physiologic and metabolic activities, such as thermogenesis and lipolysis in brown and white adipose tissue, respectively (BAT, WAT), negative inotropic effects in cardiomyocytes, and relaxation of the blood vessels and the urinary bladder. The β3-AR has been suggested as a potential target for cancer treatment, both in adult and pediatric tumors, since under hypoxia its upregulation in the tumor microenvironment (TME) regulates stromal cell differentiation, tumor growth and metastases, signifying that its agonism/antagonism could be useful for clinical benefits. Promising results in cancer research have proposed the β3-AR being targeted for the treatment of many conditions, with some drugs, at present, undergoing phase II and III clinical trials. In this review, we report the scientific journey followed by the research from the β3-Ars' discovery, with focus on the β3-Ars' role in cancer initiation and progression that elects it an intriguing target for novel antineoplastic approaches. The overview highlights the great potential of the β3-AR, both in physiologic and pathologic conditions, with the intention to display the possible benefits of β3-AR modulation in cancer reality.
Topics: Adult; Child; Humans; Adipose Tissue, Brown; Adipose Tissue, White; Lipolysis; Receptors, Adrenergic, beta-3; Neoplasms
PubMed: 38397396
DOI: 10.3390/biom14020159 -
Proceedings of the National Academy of... Aug 2023Body fat distribution is a heritable risk factor for cardiovascular and metabolic disease. In humans, rare Inhibin beta E (, activin E) loss-of-function variants are...
Body fat distribution is a heritable risk factor for cardiovascular and metabolic disease. In humans, rare Inhibin beta E (, activin E) loss-of-function variants are associated with a lower waist-to-hip ratio and protection from type 2 diabetes. Hepatic fatty acid sensing promotes expression during fasting and in obese individuals, yet it is unclear how the hepatokine activin E governs body shape and energy metabolism. Here, we uncover activin E as a regulator of adipose energy storage. By suppressing β-agonist-induced lipolysis, activin E promotes fat accumulation and adipocyte hypertrophy and contributes to adipose dysfunction in mice. Mechanistically, we demonstrate that activin E elicits its effect on adipose tissue through ACVR1C, activating SMAD2/3 signaling and suppressing PPARG target genes. Conversely, loss of activin E or ACVR1C in mice increases fat utilization, lowers adiposity, and drives PPARG-regulated gene signatures indicative of healthy adipose function. Our studies identify activin E-ACVR1C as a metabolic rheostat promoting liver-adipose cross talk to restrain excessive fat breakdown and preserve fat mass during prolonged fasting, a mechanism that is maladaptive in obese individuals.
Topics: Humans; Mice; Animals; Lipolysis; Activins; Adiposity; Diabetes Mellitus, Type 2; PPAR gamma; Obesity; Adipose Tissue; Activin Receptors, Type I
PubMed: 37523551
DOI: 10.1073/pnas.2309967120 -
Cancer Research Nov 2023Bevacizumab is an anti-VEGF monoclonal antibody that plays an important role in the combination treatment of advanced colorectal cancer. However, resistance remains a...
UNLABELLED
Bevacizumab is an anti-VEGF monoclonal antibody that plays an important role in the combination treatment of advanced colorectal cancer. However, resistance remains a major hurdle limiting bevacizumab efficacy, highlighting the importance of identifying a mechanism of antiangiogenic therapy resistance. Here, we investigated biophysical properties of the extracellular matrix (ECM) related to metabolic processes and acquired resistance to bevacizumab. Evaluation of paired pre- and posttreatment samples of liver metastases from 20 colorectal cancer patients treated with combination bevacizumab therapy, including 10 responders and 10 nonresponders, indicated that ECM deposition in liver metastases and a highly activated fatty acid oxidation (FAO) pathway were elevated in nonresponders after antiangiogenic therapy compared with responders. In mouse models of liver metastatic colorectal cancer (mCRC), anti-VEGF increased ECM deposition and FAO in colorectal cancer cells, and treatment with the FAO inhibitor etomoxir enhanced the efficacy of antiangiogenic therapy. Hepatic stellate cells (HSC) were essential for matrix stiffness-mediated FAO in colon cancer cells. Matrix stiffness activated lipolysis in HSCs via the focal adhesion kinase (FAK)/yes-associated protein (YAP) pathway, and free fatty acids secreted by HSCs were absorbed as metabolic substrates and activated FAO in colon cancer cells. Suppressing HSC lipolysis using FAK and YAP inhibition enhanced the efficacy of anti-VEGF therapy. Together, these results indicate that bevacizumab-induced ECM remodeling triggers lipid metabolic cross-talk between colon cancer cells and HSCs. This metabolic mechanism of bevacizumab resistance mediated by the physical tumor microenvironment represents a potential therapeutic target for reversing drug resistance.
SIGNIFICANCE
Extracellular matrix stiffening drives bevacizumab resistance by stimulating hepatic stellate cells to provide fuel for mCRC cells in the liver, indicating a potential metabolism-based therapeutic strategy for overcoming resistance.
Topics: Animals; Mice; Humans; Bevacizumab; Liver Neoplasms; Colorectal Neoplasms; Colonic Neoplasms; Stromal Cells; Lipids; Tumor Microenvironment
PubMed: 37610655
DOI: 10.1158/0008-5472.CAN-23-0025 -
Journal of Diabetes Science and... May 2024Ketone bodies are an energy substrate produced by the liver and used during states of low carbohydrate availability, such as fasting or prolonged exercise. High ketone... (Review)
Review
Ketone bodies are an energy substrate produced by the liver and used during states of low carbohydrate availability, such as fasting or prolonged exercise. High ketone concentrations can be present with insulin insufficiency and are a key finding in diabetic ketoacidosis (DKA). During states of insulin deficiency, lipolysis increases and a flood of circulating free fatty acids is converted in the liver into ketone bodies-mainly beta-hydroxybutyrate and acetoacetate. During DKA, beta-hydroxybutyrate is the predominant ketone in blood. As DKA resolves, beta-hydroxybutyrate is oxidized to acetoacetate, which is the predominant ketone in the urine. Because of this lag, a urine ketone test might be increasing even as DKA is resolving. Point-of-care tests are available for self-testing of blood ketones and urine ketones through measurement of beta-hydroxybutyrate and acetoacetate and are cleared by the US Food and Drug Administration (FDA). Acetone forms through spontaneous decarboxylation of acetoacetate and can be measured in exhaled breath, but currently no device is FDA-cleared for this purpose. Recently, technology has been announced for measuring beta-hydroxybutyrate in interstitial fluid. Measurement of ketones can be helpful to assess compliance with low carbohydrate diets; assessment of acidosis associated with alcohol use, in conjunction with SGLT2 inhibitors and immune checkpoint inhibitor therapy, both of which can increase the risk of DKA; and to identify DKA due to insulin deficiency. This article reviews the challenges and shortcomings of ketone testing in diabetes treatment and summarizes emerging trends in the measurement of ketones in the blood, urine, breath, and interstitial fluid.
Topics: Humans; Diabetic Ketoacidosis; Ketones; Ketone Bodies; Acetoacetates; 3-Hydroxybutyric Acid; Breath Tests; Point-of-Care Testing
PubMed: 36794812
DOI: 10.1177/19322968231152236 -
Endocrinology and Metabolism (Seoul,... Apr 2024Glucocorticoids provide a potent therapeutic response and are widely used to treat a variety of diseases, including coronavirus disease 2019 (COVID-19) infection.... (Review)
Review
Glucocorticoids provide a potent therapeutic response and are widely used to treat a variety of diseases, including coronavirus disease 2019 (COVID-19) infection. However, the issue of glucocorticoid-induced hyperglycemia (GIH), which is observed in over one-third of patients treated with glucocorticoids, is often neglected. To improve the clinical course and prognosis of diseases that necessitate glucocorticoid therapy, proper management of GIH is essential. The key pathophysiology of GIH includes systemic insulin resistance, which exacerbates hepatic steatosis and visceral obesity, as well as proteolysis and lipolysis of muscle and adipose tissue, coupled with β-cell dysfunction. For patients on glucocorticoid therapy, risk stratification should be conducted through a detailed baseline evaluation, and frequent glucose monitoring is recommended to detect the onset of GIH, particularly in high-risk individuals. Patients with confirmed GIH who require treatment should follow an insulin-centered regimen that varies depending on whether they are inpatients or outpatients, as well as the type and dosage of glucocorticoid used. The ideal strategy to maintain normoglycemia while preventing hypoglycemia is to combine basal-bolus insulin and correction doses with a continuous glucose monitoring system. This review focuses on the current understanding and latest evidence concerning GIH, incorporating insights gained from the COVID-19 pandemic.
Topics: Humans; Glucocorticoids; Hyperglycemia; COVID-19; SARS-CoV-2; Blood Glucose; Insulin; Insulin Resistance; COVID-19 Drug Treatment
PubMed: 38532282
DOI: 10.3803/EnM.2024.1951 -
Cell Metabolism Nov 2023The PNPLA3 I148M variant is the major genetic risk factor for all stages of fatty liver disease, but the underlying pathophysiology remains unclear. We studied the...
The PNPLA3 I148M variant is the major genetic risk factor for all stages of fatty liver disease, but the underlying pathophysiology remains unclear. We studied the effect of this variant on hepatic metabolism in homozygous carriers and non-carriers under multiple physiological conditions with state-of-the-art stable isotope techniques. After an overnight fast, carriers had higher plasma β-hydroxybutyrate concentrations and lower hepatic de novo lipogenesis (DNL) compared to non-carriers. After a mixed meal, fatty acids were channeled toward ketogenesis in carriers, which was associated with an increase in hepatic mitochondrial redox state. During a ketogenic diet, carriers manifested increased rates of intrahepatic lipolysis, increased plasma β-hydroxybutyrate concentrations, and decreased rates of hepatic mitochondrial citrate synthase flux. These studies demonstrate that homozygous PNPLA3 I148M carriers have hepatic mitochondrial dysfunction leading to reduced DNL and channeling of carbons to ketogenesis. These findings have implications for understanding why the PNPLA3 variant predisposes to progressive liver disease.
Topics: Humans; Lipogenesis; 3-Hydroxybutyric Acid; Liver; Non-alcoholic Fatty Liver Disease; Mitochondria; Genetic Predisposition to Disease
PubMed: 37909034
DOI: 10.1016/j.cmet.2023.10.008 -
JCI Insight Mar 2024Excessive lipolysis in white adipose tissue (WAT) leads to insulin resistance (IR) and ectopic fat accumulation in insulin-sensitive tissues. However, the impact of...
Excessive lipolysis in white adipose tissue (WAT) leads to insulin resistance (IR) and ectopic fat accumulation in insulin-sensitive tissues. However, the impact of Gi-coupled receptors in restraining adipocyte lipolysis through inhibition of cAMP production remained poorly elucidated. Given that the Gi-coupled P2Y13 receptor (P2Y13-R) is a purinergic receptor expressed in WAT, we investigated its role in adipocyte lipolysis and its effect on IR and metabolic dysfunction-associated steatotic liver disease (MASLD). In humans, mRNA expression of P2Y13-R in WAT was negatively correlated to adipocyte lipolysis. In mice, adipocytes lacking P2Y13-R displayed higher intracellular cAMP levels, indicating impaired Gi signaling. Consistently, the absence of P2Y13-R was linked to increased lipolysis in adipocytes and WAT explants via hormone-sensitive lipase activation. Metabolic studies indicated that mice lacking P2Y13-R showed a greater susceptibility to diet-induced IR, systemic inflammation, and MASLD compared with their wild-type counterparts. Assays conducted on precision-cut liver slices exposed to WAT conditioned medium and on liver-specific P2Y13-R-knockdown mice suggested that P2Y13-R activity in WAT protects from hepatic steatosis, independently of liver P2Y13-R expression. In conclusion, our findings support the idea that targeting adipose P2Y13-R activity may represent a pharmacological strategy to prevent obesity-associated disorders, including type 2 diabetes and MASLD.
Topics: Animals; Female; Humans; Male; Mice; Adipocytes; Adipose Tissue; Adipose Tissue, White; Fatty Liver; Insulin Resistance; Lipolysis; Liver; Mice, Inbred C57BL; Mice, Knockout; Receptors, Purinergic P2
PubMed: 38470490
DOI: 10.1172/jci.insight.175623 -
Nutrients Jul 2023Besides their common use as an adaptogen, (Willd.) Iljin. rhizome and its root extract (RCE) are also reported to beneficially affect lipid metabolism. The main...
Besides their common use as an adaptogen, (Willd.) Iljin. rhizome and its root extract (RCE) are also reported to beneficially affect lipid metabolism. The main characteristic secondary metabolites of RCE are phytoecdysteroids. In order to determine an RCE's phytoecdysteroid profile, a novel, sensitive, and robust high-performance thin-layer chromatography (HPTLC) method was developed and validated. Moreover, a comparative analysis was conducted to investigate the effects of RCE and its secondary metabolites on adipogenesis and adipolysis. The evaluation of the anti-adipogenic and lipolytic effects was performed using human Simpson-Golabi-Behmel syndrome cells, where lipid staining and measurement of released glycerol and free fatty acids were employed. The HPTLC method confirmed the presence of 20-hydroxyecdysone (20E), ponasterone A (PA), and turkesterone (TU) in RCE. The observed results revealed that RCE, 20E, and TU significantly reduced lipid accumulation in human adipocytes, demonstrating their anti-adipogenic activity. Moreover, RCE and 20E were found to effectively stimulate basal lipolysis. However, no significant effects were observed with PA and TU applications. Based on our findings, RCE and 20E affect both lipogenesis and lipolysis, while TU only restrains adipogenesis. These results are fundamental for further investigations.
Topics: Humans; Mice; Animals; Adipogenesis; Leuzea; Plant Extracts; Lipid Metabolism; Lipolysis; Lipids; 3T3-L1 Cells
PubMed: 37447387
DOI: 10.3390/nu15133061