RESUMO
BACKGROUND: Type 2 diabetes mellitus (T2DM) is characterized by disrupted glucose homeostasis and metabolic abnormalities, with oxidative stress and inflammation playing pivotal roles in its pathophysiology. Poly(ADP-ribosyl)ation (PARylation) is a post-translational process involving the addition of ADP-ribose polymers (PAR) to target proteins. While preclinical studies have implicated PARylation in the interplay between oxidative stress and inflammation in T2DM, direct clinical evidence in humans remains limited. This study investigates the relationship between oxidative stress, PARylation, and inflammatory response in T2DM patients. METHODS: This cross-sectional investigation involved 61 T2DM patients and 48 controls. PAR levels were determined in peripheral blood cells (PBMC) by ELISA-based methodologies. Oxidative stress was assessed in plasma and PBMC. In plasma, we monitored reactive oxygen metabolites (d-ROMs) and ferric-reducing antioxidant power. In PBMC, we measured the expression of antioxidant enzymes SOD1, GPX1 and CAT by qPCR. Further, we evaluated the expression of inflammatory mediators such as IL6, TNF-α, CD68 and MCP1 by qPCR in PBMC. RESULTS: T2DM patients exhibited elevated PAR levels in PBMC and increased d-ROMs in plasma. Positive associations were found between PAR levels and d-ROMs, suggesting a link between oxidative stress and altered PAR metabolism. Mediation analysis revealed that d-ROMs mediate the association between HbA1c levels and PAR, indicating oxidative stress as a potential driver of increased PARylation in T2DM. Furthermore, elevated PAR levels were found to be associated with increased expression of pro-inflammatory cytokines IL6 and TNF-α in the PBMC of T2DM patients. CONCLUSIONS: This study highlights that hyperactivation of PARylation is associated with poor glycemic control and the resultant oxidative stress in T2DM. The increase of PAR levels is correlated with the upregulation of key mediators of the inflammatory response. Further research is warranted to validate these findings and explore their clinical implications.
Assuntos
Diabetes Mellitus Tipo 2 , Inflamação , Leucócitos Mononucleares , Estresse Oxidativo , Espécies Reativas de Oxigênio , Humanos , Diabetes Mellitus Tipo 2/metabolismo , Masculino , Feminino , Pessoa de Meia-Idade , Espécies Reativas de Oxigênio/metabolismo , Inflamação/metabolismo , Leucócitos Mononucleares/metabolismo , Estudos Transversais , Poli Adenosina Difosfato Ribose/metabolismo , Superóxido Dismutase-1/metabolismo , Superóxido Dismutase-1/genética , Glutationa Peroxidase GPX1 , Glutationa Peroxidase/metabolismo , Glutationa Peroxidase/sangue , Biomarcadores/sangue , Adulto , Idoso , Fator de Necrose Tumoral alfa/metabolismo , Fator de Necrose Tumoral alfa/sangue , Catalase/metabolismo , Catalase/sangueRESUMO
Brain insulin resistance links the failure of energy metabolism with cognitive decline in both type 2 Diabetes Mellitus (T2D) and Alzheimer's disease (AD), although the molecular changes preceding overt brain insulin resistance remain unexplored. Abnormal biliverdin reductase-A (BVR-A) levels were observed in both T2D and AD and were associated with insulin resistance. Here, we demonstrate that reduced BVR-A levels alter insulin signaling and mitochondrial bioenergetics in the brain. Loss of BVR-A leads to IRS1 hyper-activation but dysregulates Akt-GSK3ß complex in response to insulin, hindering the accumulation of pGSK3ßS9 into the mitochondria. This event impairs oxidative phosphorylation and fosters the activation of the mitochondrial Unfolded Protein Response (UPRmt). Remarkably, we unveil that BVR-A is required to shuttle pGSK3ßS9 into the mitochondria. Our data sheds light on the intricate interplay between insulin signaling and mitochondrial metabolism in the brain unraveling potential targets for mitigating the development of brain insulin resistance and neurodegeneration.
Assuntos
Glicogênio Sintase Quinase 3 beta , Resistência à Insulina , Insulina , Mitocôndrias , Oxirredutases atuantes sobre Doadores de Grupo CH-CH , Transdução de Sinais , Glicogênio Sintase Quinase 3 beta/metabolismo , Mitocôndrias/metabolismo , Fosforilação , Animais , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/metabolismo , Insulina/metabolismo , Camundongos , Humanos , Encéfalo/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Resposta a Proteínas não Dobradas , Diabetes Mellitus Tipo 2/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Doença de Alzheimer/metabolismoRESUMO
AIM: We examined whether metabolic dysfunction-associated steatotic liver disease (MASLD) with or without significant fibrosis (assessed by validated non-invasive biomarkers) was associated with an increased risk of prevalent chronic kidney disease (CKD) or diabetic retinopathy in people with type 1 diabetes mellitus (T1DM). METHODS: We performed a retrospective multicenter cross-sectional study involving 1,409 adult outpatients with T1DM, in whom hepatic steatosis index (HSI) and fibrosis (FIB)-4 index were calculated for non-invasively detecting hepatic steatosis (defined by HSI > 36), with or without coexisting significant fibrosis (FIB-4 index ≥ 1.3 or < 1.3). CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 or urine albumin/creatinine ratio ≥ 3.0 mg/mmol. The presence of diabetic retinopathy was also recorded in all participants. RESULTS: Patients with MASLD and significant fibrosis (n = 93) had a remarkably higher prevalence of CKD and diabetic retinopathy than their counterparts with MASLD without fibrosis (n = 578) and those without steatosis (n = 738). After adjustment for sex, diabetes duration, hemoglobin A1c, hypertension, and use of antihypertensive or lipid-lowering medications, patients with SLD and significant fibrosis had a higher risk of prevalent CKD (adjusted-odds ratio 1.76, 95 % confidence interval 1.05-2.96) than those without steatosis. Patients with MASLD without fibrosis had a higher risk of prevalent retinopathy (adjusted-odds ratio 1.49, 95 % CI 1.13-1.46) than those without steatosis. CONCLUSION: This is the largest cross-sectional study showing that MASLD with and without coexisting significant fibrosis was associated, independently of potential confounders, with an increased risk of prevalent CKD and retinopathy in adults with T1DM.
Assuntos
Diabetes Mellitus Tipo 1 , Retinopatia Diabética , Fígado Gorduroso , Insuficiência Renal Crônica , Doenças Retinianas , Adulto , Humanos , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/epidemiologia , Retinopatia Diabética/epidemiologia , Prevalência , Estudos Transversais , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/epidemiologia , Fígado Gorduroso/complicações , Doenças Retinianas/complicações , Fibrose , Cirrose Hepática/complicações , Cirrose Hepática/epidemiologiaRESUMO
Lipopolysaccharide (LPS) and its binding protein LBP have emerged as potential contributors to the progression from overweight/obesity to overt metabolic diseases and NAFLD. While LPS is known to activate hepatocyte inflammation, thus contributing toward NAFLD development, the role of LBP is more intricate, and recent data have shown that experimental reduction in hepatic LBP promotes NAFLD progression. In this cross-sectional investigation, we evaluated circulating LBP in relation to obesity, NAFLD, visceral adipose tissue (VAT) inflammation, and type 2 diabetes (T2D). We recruited 186 individuals (M/F: 81/105; age: 47 ± 10.4 years; BMI: 35.5 ± 8.6 kg/m2); a subgroup (n = 81) underwent bariatric surgery with intra-operative VAT and liver biopsies. LBP levels were higher in obese individuals than non-obese individuals but were inversely correlated with the parameters of glucose metabolism. Reduced LBP predicted T2D independent of age, sex, and BMI (p < 0.001). LBP levels decreased across more severe stages of hepatosteatosis and lobular inflammation, and were inversely associated with VAT inflammation signatures. In conclusion, LBP levels are increased in obese individuals and are associated with a more favorable metabolic profile and lower NAFLD/NASH prevalence. A possible explanation for these findings is that hepatic LBP production may be triggered by chronic caloric excess and facilitate LPS degradation in the liver, thus protecting these individuals from the metabolic consequences of obesity.
Assuntos
Diabetes Mellitus Tipo 2 , Hepatopatia Gordurosa não Alcoólica , Humanos , Adulto , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Lipopolissacarídeos/metabolismo , Estudos Transversais , Obesidade/metabolismo , Fígado/metabolismo , Inflamação/metabolismoRESUMO
AIM: We examined whether different insulin administration modalities, i.e., multiple daily injections (MDI) or continuous subcutaneous insulin infusion (CSII by insulin pumps), are differently associated with the risk of having metabolic dysfunction-associated fatty liver disease (MAFLD), with or without coexisting significant liver fibrosis (assessed by validated non-invasive biomarkers), in adults with type 1 diabetes mellitus (T1DM). METHODS: We conducted a retrospective, multicenter, cross-sectional study involving 1,417 adult individuals with established T1DM treated with MDI or CSII. We calculated hepatic steatosis index (HSI) and fibrosis (FIB)-4 index for non-invasively detecting MAFLD (defined by HSI >36), with or without coexisting significant fibrosis (defined by FIB-4 index ≥ 1.3 or <1.3, respectively). RESULTS: Compared to the MDI group (n = 1,161), insulin-pump users (n = 256; 18.1%) were more likely to be younger (mean age: 40 vs. 48 years, P < 0.001), had better glycemic control (mean hemoglobin A1c: 7.7% vs. 7.9%, P = 0.025) and a markedly lower prevalence of MAFLD with coexisting significant fibrosis (2.7% vs. 8.1%, P = 0.010), but a comparable prevalence of MAFLD without fibrosis. In multinomial logistic regression analysis, CSII therapy was associated with a â¼70%-lower risk of MAFLD with significant fibrosis (unadjusted odds ratio 0.32, 95% confidence interval 0.14-0.70; P = 0.004), but this association was no longer significant after adjustment for age, hemoglobin A1c and other potential confounders. CONCLUSION: The lower prevalence of MAFLD with coexisting significant fibrosis we observed in adults with T1DM using CSII therapy, compared to those using MDI therapy, is primarily mediated by inter-group differences in age.
Assuntos
Diabetes Mellitus Tipo 1 , Hepatopatia Gordurosa não Alcoólica , Adulto , Humanos , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/epidemiologia , Hemoglobinas Glicadas , Estudos Retrospectivos , Estudos Transversais , Insulina/efeitos adversos , Sistemas de Infusão de Insulina , FibroseRESUMO
BACKGROUND: We assessed whether hepatic steatosis with or without significant fibrosis (determined by validated non-invasive biomarkers) is associated with an increased 10-year estimated risk for cardiovascular disease (CVD) in people with type 1 diabetes mellitus (T1DM). METHODS: We conducted a retrospective, multicenter, cross-sectional study involving 1,254 adults with established T1DM without pre-existing CVD. We used the hepatic steatosis index (HSI) and fibrosis (FIB)-4 index for non-invasively detecting hepatic steatosis (defined as HSI > 36), with or without coexisting significant fibrosis (defined as FIB-4 index ≥ 1.3 or < 1.3). We calculated the Steno type 1 risk engine and the atherosclerotic CVD (ASCVD) risk score to estimate the 10-year risk of developing a first fatal or nonfatal CVD event. RESULTS: Using the Steno type 1 risk engine, a significantly greater proportion of patients with hepatic steatosis and significant fibrosis (n = 91) had a high 10-year estimated CVD risk compared to those with hepatic steatosis alone (n = 509) or without steatosis (n = 654) (75.8% vs. 23.2% vs. 24.9%, p < 0.001). After adjustment for sex, BMI, diabetes duration, hemoglobin A1c, chronic kidney disease, and lipid-lowering medication use, patients with hepatic steatosis and significant fibrosis had an increased 10-year estimated risk of developing a first fatal or nonfatal CVD event (adjusted-odds ratio 11.4, 95% confidence interval 3.54-36.9) than those without steatosis. We observed almost identical results using the ASCVD risk calculator. CONCLUSIONS: The 10-year estimated CVD risk is remarkably greater in T1DM adults with hepatic steatosis and significant fibrosis than in their counterparts with hepatic steatosis alone or without steatosis.
Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 1 , Hepatopatia Gordurosa não Alcoólica , Humanos , Adulto , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/epidemiologia , Hepatopatia Gordurosa não Alcoólica/diagnóstico , Estudos Retrospectivos , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/complicações , Estudos Transversais , Cirrose Hepática/diagnóstico , Cirrose Hepática/epidemiologiaRESUMO
Neurotensin (NT) is a small protein implicated in the regulation of energy balance which acts as both a neurotransmitter in the central nervous system and as a gastrointestinal peptide. In the gut, NT is secreted after fat ingestion and promotes the absorption of fatty acids. The circulating levels of its precursor, pro-NT, predicts the presence and development of metabolic and cardiovascular diseases. Despite the extensive knowledge on the dynamic changes that occur to pro-NT = after fat load, the determinants of fasting pro-NT are unknown. The aim of this study was to determine the possible genetic regulation of plasma pro-NT. The NT gene (NTS) was sequenced for potential functional variants, evaluating its entire genomic and potentially regulatory regions, in DNA from 28 individuals, stratified by low and high pro-NT levels. The identified variant differently distributed in the two pro-NT subgroups was genotyped in a cohort of nine hundred and thirty-two overweight/obese children and adolescents. A total of seven sequence variations across the NTS gene, none of them located in coding regions, were identified. The rs2234762 polymorphism, sited in the NTS gene promoter, was statistically more frequent in the lowest pro-NTS level group. Carriers of the rs2234762 variant showed lower pro-NT levels, after adjusting for sex, age, BMI, triglycerides and the Tanner stage. Having NTS rs2234762 predicted less pronounced insulin resistance at the 6.5-year follow-up with OR: 0.46 (0.216-0.983), at the logistic regression analysis adjusted for age, sex and BMI. In conclusion, the NTS rs2234762 gene variant is a determinant of reduced circulating pro-NT levels in overweight and obese children, which predisposes this group to a more favorable metabolic profile and a reduced insulin resistance later in life, independently from metabolic confounders.
Assuntos
Resistência à Insulina , Obesidade Infantil , Adolescente , Humanos , Criança , Neurotensina/genética , Neurotensina/metabolismo , Resistência à Insulina/genética , Sobrepeso/genética , Ácidos GraxosRESUMO
Type 2 diabetes mellitus (T2DM) is associated with an increased fracture risk. Our study aimed to explore differences in bone alterations between T2DM women and controls and to assess clinical predictors of bone impairment in T2DM. For this observational case control study, we recruited 126 T2DM female patients and 117 non-diabetic, age- and BMI-comparable women, who underwent clinical examination, routine biochemistry and dual-energy X-ray absorptiometry (DXA) scans for bone mineral density (BMD) and trabecular bone score (TBS) assessment-derived indexes. These were correlated to metabolic parameters, such as glycemic control and lipid profile, by bivariate analyses, and significant variables were entered in multivariate adjusted models to detect independent determinants of altered bone status in diabetes. The T2DM patients were less represented in the normal bone category compared with controls (5% vs. 12%; p = 0.04); T2DM was associated with low TBS (OR: 2.47, C.I. 95%: 1.19-5.16, p = 0.016) in a regression model adjusted for age, menopausal status and BMI. In women with T2DM, TBS directly correlated with plasma high-density lipoprotein cholesterol (HDL-c) (p = 0.029) and vitamin D (p = 0.017) levels. An inverse association was observed with menopausal status (p < 0.001), metabolic syndrome (p = 0.014), BMI (p = 0.005), and waist circumference (p < 0.001). In the multivariate regression analysis, lower HDL-c represented the main predictor of altered bone quality in T2DM, regardless of age, menopausal status, BMI, waist circumference, statin treatment, physical activity, and vitamin D (p = 0.029; R2 = 0.47), which likely underlies common pathways between metabolic disease and bone health in diabetes.
Assuntos
Colestanos , Diabetes Mellitus Tipo 2 , Humanos , Feminino , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Estudos de Casos e Controles , HDL-Colesterol , Densidade Óssea , Osso Esponjoso , Vitamina D/uso terapêutico , Vértebras LombaresRESUMO
Biliverdin reductase-A (BVRA) is involved in the regulation of insulin signaling and the maintenance of glucose homeostasis. Previous research showed that BVRA alterations are associated with the aberrant activation of insulin signaling in dysmetabolic conditions. However, whether BVRA protein levels change dynamically within the cells in response to insulin and/or glucose remains an open question. To this aim, we evaluated changes of intracellular BVRA levels in peripheral blood mononuclear cells (PBMC) collected during the oral glucose tolerance test (OGTT) in a group of subjects with different levels of insulin sensitivity. Furthermore, we looked for significant correlations with clinical measures. Our data show that BVRA levels change dynamically during the OGTT in response to insulin, and greater BVRA variations occur in those subjects with lower insulin sensitivity. Changes of BVRA significantly correlate with indexes of increased insulin resistance and insulin secretion (HOMA-IR, HOMA-ß, and insulinogenic index). At the multivariate regression analysis, the insulinogenic index independently predicted increased BVRA area under curve (AUC) during the OGTT. This pilot study showed, for the first time, that intracellular BVRA protein levels change in response to insulin during OGTT and are greater in subjects with lower insulin sensitivity, supporting the role of BVR-A in the dynamic regulation of the insulin signaling pathway.
Assuntos
Resistência à Insulina , Insulina , Humanos , Glicemia/metabolismo , Glucose , Insulina/metabolismo , Resistência à Insulina/fisiologia , Insulina Regular Humana , Leucócitos Mononucleares/metabolismo , Projetos PilotoRESUMO
CONTEXT: Patients with type 1 diabetes (T1D) have higher cardiovascular disease (CVD) risk than the general population. OBJECTIVE: This observational study aims to evaluate sex-related differences in CVD prevalence and CVD risk estimates in a large cohort of T1D adults. METHODS: We conducted a multicenter, cross-sectional study involving 2041 patients with T1D (mean age 46 years; 44.9% women). In patients without pre-existing CVD (primary prevention), we used the Steno type 1 risk engine to estimate the 10-year risk of developing CVD events. RESULTS: CVD prevalence (n = 116) was higher in men than in women aged ≥55 years (19.2 vs 12.8%, P = .036), but comparable between the 2 sexes in those aged <55 years (P = .91). In patients without pre-existing CVD (n = 1925), mean 10-year estimated CVD risk was 15.4 ± 0.4% without any significant sex difference. However, stratifying this patient group by age, the 10-year estimated CVD risk was significantly higher in men than in women until age 55 years (P < .001), but this risk equalized after this age. Carotid artery plaque burden was significantly associated with age ≥55 years and with a medium and high 10-year estimated CVD risk, without any significant sex difference. Diabetic retinopathy and sensory-motor neuropathy were also associated with higher 10-year CVD risk and female sex. CONCLUSION: Both men and women with T1D are at high CVD risk. The 10-year estimated CVD risk was higher in men aged <55 years than in women of similar age, but these sex differences disappeared at age ≥55 years, suggesting that female sex was no longer protective.
Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 1 , Adulto , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Criança , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/epidemiologia , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/complicações , Fatores de Risco , Caracteres Sexuais , Estudos Transversais , Fatores de Risco de Doenças CardíacasRESUMO
BACKGROUND AND PURPOSE: Chronic liver diseases are associated with increased bone fracture risk, mostly in end-stage disease and cirrhosis; besides, data in non-alcoholic fatty liver disease (NAFLD) are limited. Aim of this study was to investigate bone mineralization and microstructure in obese individuals with NAFLD in relation to the estimated liver fibrosis. METHODS: For this cross-sectional investigation, we analyzed data from 1872 obese individuals (44.6 ± 14.1 years, M/F: 389/1483; BMI: 38.3 ± 5.3 kg/m2) referring to the Endocrinology outpatient clinics of Sapienza University, Rome, Italy. Participants underwent clinical work-up, Dual-Energy X-ray Absorptiometry for assessing bone mineral density (BMD) and microarchitecture (trabecular bone score, TBS). Liver fibrosis was estimated by Fibrosis Score 4 (FIB-4). Serum parathyroid hormone (PTH), 25(OH) vitamin D, osteocalcin and IGF-1 levels were measured. RESULTS: Obese individuals with osteopenia/osteoporosis had greater FIB-4 than those with normal BMD (p < 0.001). FIB-4 progressively increased in presence of degraded bone microarchitecture (p < 0.001) and negatively correlated with the serum osteocalcin (p < 0.001) and IGF-1 (p < 0.001), which were both reduced in presence of osteopenia/osteoporosis. FIB-4 predicted IGF-1 reduction in multivariable regression models adjusted for confounders (ß: - 0.18, p < 0.001). Higher FIB-4 predicted bone fragility with OR 3.8 (95%C.I:1.5-9.3); this association persisted significant after adjustment for sex, age, BMI, diabetes, smoking status and PTH at the multivariable logistic regression analysis (OR 1.91 (95%C.I:1.15-3.17), p < 0.01), with AUROC = 0.842 (95%C.I:0.795-0.890; p < 0.001). CONCLUSION: Our data indicate the presence of a tight relation between NAFLD-related liver fibrosis, lower bone mineral density and degraded microarchitecture in obese individuals, suggesting potential common pathways underlying liver and bone involvement in obesity and insulin resistance-associated disorders.
Assuntos
Hepatopatia Gordurosa não Alcoólica , Osteoporose , Humanos , Hepatopatia Gordurosa não Alcoólica/complicações , Fator de Crescimento Insulin-Like I , Calcificação Fisiológica , Estudos Transversais , Osteocalcina , Cirrose Hepática/complicações , Obesidade/complicações , Densidade Óssea , Osteoporose/complicações , FibroseRESUMO
Dipeptidyl peptidase 4 (DPP4) is a molecule implicated in the regulation of metabolic homeostasis and inflammatory processes, and it exerts its main action through its enzymatic activity. DPP4 represents the enzyme most involved in the catabolism of incretin hormones; thus, its activity impacts appetite, energy balance, and the fine regulation of glucose homeostasis. Indeed, DPP4 inhibitors represent a class of antidiabetic agents widely used for the treatment of Type 2 diabetes mellitus (T2DM). DPP4 also acts as an adipokine and is mainly secreted by the adipose tissue, mostly from mature adipocytes of the visceral compartment, where it exerts autocrine and paracrine activities. DPP4 can disrupt insulin signaling within the adipocyte and in other target cells and tissues, where it also favors the development of a proinflammatory environment. This is likely at the basis of the presence of elevated circulating DPP4 levels in several metabolic diseases. In this review, we summarize the most recent evidence of the role of the DPP4 as an adipokine-regulating glucose/insulin metabolism and fat homeostasis, with a particular focus on clinical outcomes associated with its increased secretion in the presence of adipose tissue accumulation and dysfunction.
RESUMO
Insulin signaling is a conserved pathway that orchestrates glucose and lipid metabolism, energy balance, and inflammation, and its dysregulation compromises the homeostasis of multiple systems. Insulin resistance is a shared hallmark of several metabolic diseases, including obesity, metabolic syndrome, and type 2 diabetes, and has been associated with cognitive decline during aging and dementia. Numerous mechanisms promoting the development of peripheral and central insulin resistance have been described, although most of them were not completely clarified. In the last decades, several studies have highlighted that biliverdin reductase-A (BVR-A), over its canonical role in the degradation of heme, acts as a regulator of insulin signaling. Evidence from human and animal studies show that BVR-A alterations are associated with the aberrant activation of insulin signaling, metabolic syndrome, liver steatosis, and visceral adipose tissue inflammation in obese and diabetic individuals. In addition, recent findings demonstrated that reduced BVR-A levels or impaired BVR-A activation contribute to the development of brain insulin resistance and metabolic alterations in Alzheimer's disease. In this narrative review, we will provide an overview on the literature by focusing on the role of BVR-A in the regulation of insulin signaling and how BVR-A alterations impact on cell dysfunctions in both metabolic and neurodegenerative disorders.
Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Síndrome Metabólica , Doenças Neurodegenerativas , Animais , Diabetes Mellitus Tipo 2/metabolismo , Inflamação , Insulina/metabolismo , Resistência à Insulina/fisiologia , Obesidade , Oxirredutases atuantes sobre Doadores de Grupo CH-CHRESUMO
Type 2 diabetes is characterized by impairment in insulin secretion, with an established genetic contribution. We aimed to evaluate common and low-frequency (1-5%) variants in nine genes strongly associated with insulin secretion by targeted sequencing in subjects selected from the extremes of insulin release measured by the disposition index. Collapsing data by gene and/or function, the association between disposition index and nonsense variants were significant, also after adjustment for confounding factors (OR = 0.25, 95% CI = 0.11-0.59, p = 0.001). Evaluating variants individually, three novel variants in ARAP1, IGF2BP2 and GCK, out of eight reaching significance singularly, remained associated after adjustment. Constructing a genetic risk model combining the effects of the three variants, only carriers of the ARAP1 and IGF2BP2 variants were significantly associated with a reduced probability to be in the lower, worst, extreme of insulin secretion (OR = 0.223, 95% CI = 0.105-0.473, p < 0.001). Observing a high number of normal glucose tolerance between carriers, a regression posthoc analysis was performed. Carriers of genetic risk model variants had higher probability to be normoglycemic, also after adjustment (OR = 2.411, 95% CI = 1.136-5.116, p = 0.022). Thus, in our southern European cohort, nonsense variants in all nine candidate genes showed association with better insulin secretion adjusted for insulin resistance, and we established the role of ARAP1 and IGF2BP2 in modulating insulin secretion.
Assuntos
Proteínas de Transporte/genética , Diabetes Mellitus Tipo 2/epidemiologia , Proteínas Ativadoras de GTPase/genética , Resistência à Insulina , Secreção de Insulina , Obesidade/fisiopatologia , Polimorfismo de Nucleotídeo Único , Proteínas de Ligação a RNA/genética , Adulto , Estudos de Coortes , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/patologia , Feminino , Predisposição Genética para Doença , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
AIMS: Neurotensin (NT) is a gut hormone that promotes lipids absorption and controls appetite. Elevated circulating pro-NT, the stable precursor of NT, is associated with cardiovascular (CV) disease, metabolic syndrome (MS) and type 2 diabetes (T2D). Features of MS and insulin resistance are reported also in type 1 diabetes (T1D), with detrimental impact on the overall CV risk profile. Aims of the study were to evaluate plasma pro-NT in T1D patients and to test whether its levels are associated with and/or predictive of CV risk factors and overall risk profile. METHODS: For this longitudinal retrospective study, we analyzed clinical data from 41 T1D individuals referring to the diabetes outpatient clinics at Sapienza University of Rome, Italy, collected at the baseline and after 10 years. Fasting plasma pro-NT levels were measured in T1D subjects at the baseline and in 34 age-, sex-, BMI-comparable healthy individuals recruited in the same period. RESULTS: Pro-NT did not differ significantly between patients and controls (median[range] pro-NT: 156.3 [96.6-198.2] vs. 179.4 [139.7-230.7] pmol/L, p = 0.26). In T1D, greater fasting pro-NT associated with poor glycemic control at baseline and predicted increased waist circumference, reduced insulin sensitivity, dyslipidemia and hypertension at 10-year follow-up. High pro-NT predicted 10-year very-high CV risk with adjusted OR = 11 (95%C.I.: 1.4-94.5; p = 0.029). CONCLUSIONS: In T1D individuals, elevated pro-NT levels predict the development of adverse metabolic profile, which translates in higher CV risk profile at 10-year follow-up. Pro-NT represents a novel predictor/marker of CV risk factors in adults with T1D.
Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 1 , Neurotensina/sangue , Adulto , Biomarcadores/sangue , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/etiologia , Diabetes Mellitus Tipo 1/complicações , Seguimentos , Fatores de Risco de Doenças Cardíacas , Humanos , Fragmentos de Peptídeos , Estudos Retrospectivos , Fatores de RiscoRESUMO
AIM: Biliverdin reductase-A (BVR-A) other than its canonical role in the degradation pathway of heme as partner of heme oxygenase-1 (HO1), has recently drawn attention as a protein with pleiotropic functions involved in insulin-glucose homeostasis. However, whether BVR-A expression is altered in type 2 diabetes (T2D) has never been evaluated. MAIN METHODS: BVR-A protein levels were evaluated in T2D (n = 44) and non-T2D (n = 29) subjects, who underwent complete clinical workup and routine biochemistry. In parallel, levels HO1, whose expression is regulated by BVR-A as well as levels of tumor necrosis factor α (TNFα), which is a known repressor for BVR-A with pro-inflammatory properties, were also assessed. KEY FINDINGS: BVR-A levels were significantly lower in T2D subjects than in non-T2D subjects. Reduced BVR-A levels were associated with greater body mass, systolic blood pressure, fasting blood glucose (FBG), glycated hemoglobin (HbA1c), triglycerides, transaminases and TNFα, and with lower high-density lipoprotein (HDL) levels. Lower BVR-A levels are associated with reduced HO1 protein levels and the multivariate analysis showed that BVR-A represented the main determinant of HO1 levels in T2D after adjustment. In addition, reduced BVR-A levels were able to predict the presence of T2D with AUROC = 0.69. for potential confounders. SIGNIFICANCE: Our results demonstrate for the first time that BVR-A protein levels are reduced in T2D individuals, and that this alteration strictly correlates with poor glycometabolic control and a pro-inflammatory state. Hence, these observations reinforce the hypothesis that reduced BVR-A protein levels may represent a key event in the dysregulation of intracellular pathways finally leading to metabolic disorders.
Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/enzimologia , Diabetes Mellitus Tipo 2/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/metabolismo , Idoso , Feminino , Heme Oxigenase-1/metabolismo , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise MultivariadaRESUMO
BACKGROUND: Epigenetic modifications, such as DNA methylation, can influence the genetic susceptibility to type 2 diabetes mellitus (T2DM) and the progression of the disease. Our previous studies demonstrated that the regulation of the DNA methylation pattern involves the poly(ADP-ribosyl)ation (PARylation) process, a post-translational modification of proteins catalysed by the poly(ADP-ribose) polymerase (PARP) enzymes. Experimental data showed that the hyperactivation of PARylation is associated with impaired glucose metabolism and the development of T2DM. Aims of this case-control study were to investigate the association between PARylation and global and site-specific DNA methylation in T2DM and to evaluate metabolic correlates. RESULTS: Data were collected from 61 subjects affected by T2DM and 48 healthy individuals, recruited as controls. Global levels of poly(ADP-ribose) (PAR, a surrogate of PARP activity), cytosine methylation (5-methylcytosine, 5mC) and de-methylation intermediates 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC) were determined in peripheral blood cells by ELISA-based methodologies. Site-specific DNA methylation profiling of SOCS3, SREBF1 and TXNIP candidate genes was performed by mass spectrometry-based bisulfite sequencing, methyl-sensitive endonucleases digestion and by DNA immuno-precipitation. T2DM subjects presented higher PAR levels than controls. In T2DM individuals, increased PAR levels were significantly associated with higher HbA1c levels and the accumulation of the de-methylation intermediates 5hmC and 5fC in the genome. In addition, T2DM patients with higher PAR levels showed reduced methylation with increased 5hmC and 5fC levels in specific SOCS3 sites, up-regulated SOCS3 expression compared to both T2DM subjects with low PAR levels and controls. CONCLUSIONS: This study demonstrates the activation of PARylation processes in patients with T2DM, particularly in those with poor glycaemic control. PARylation is linked to dysregulation of DNA methylation pattern via activation of the DNA de-methylation cascade and may be at the basis of the differential gene expression observed in presence of diabetes.
Assuntos
Metilação de DNA/genética , Diabetes Mellitus Tipo 2/genética , Epigênese Genética/genética , Poli ADP Ribosilação/genética , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
BACKGROUND AND AIMS: Neurotensin (NT) is an intestinal peptide released after fat ingestion, which regulates appetite and facilitates lipid absorption. Elevated plasma levels of its stable precursor pro-neurotensin (pro-NT) are associated with type 2 diabetes, obesity and cardiovascular mortality in adult populations; no data on pro-NT and metabolic disease are available in children. Aim of the study was to evaluate plasma pro-NT in relation to the presence of obesity in children, and to test if high pro-NT associates with the development of metabolic impairment later in life. METHODS AND RESULTS: For this longitudinal retrospective study, we studied 151 overweight/obese children undergoing metabolic evaluations at University of Cagliari, Italy. Pro-NT was also assessed in 46 normal-weight, age-, sex-comparable normal-weight children, selected as a reference group. At the baseline, pro-NT was comparable between overweight/obese and normal-weight children and correlated positively with age (p < 0.001), triglycerides (p < 0.001) and inversely with HDL levels (p = 0.008). Plasma pro-NT associated with high triglycerides with OR = 5.9 (95%CI: 1.24-28.1; p = 0.026) after adjustment for multiple confounders. At the 6.5-year follow-up, high basal pro-NT associated with impaired ß-cell function to compensate for insulin-resistance (disposition index: r = -0.19, p = 0.035) and predicted bodyweight increase, as indicated by percentage change of standard deviation score BMI (median(95%CI) = +20.8(+4.9-+27.5)% in the highest tertile), independently from age, sex, triglycerides and insulin-resistance (standardized ß = 0.24; p = 0.036). CONCLUSIONS: Elevated pro-NT levels in children are significantly associated with weight gain later in life and may represent a marker of susceptibility to metabolic impairment in presence of obesity.
Assuntos
Metabolismo Energético , Doenças Metabólicas/sangue , Neurotensina/sangue , Obesidade Infantil/sangue , Precursores de Proteínas/sangue , Aumento de Peso , Fatores Etários , Biomarcadores/sangue , Criança , Feminino , Humanos , Estudos Longitudinais , Masculino , Doenças Metabólicas/diagnóstico , Doenças Metabólicas/fisiopatologia , Obesidade Infantil/diagnóstico , Obesidade Infantil/fisiopatologia , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Regulação para CimaRESUMO
AIMS: Experimental data suggest that visceral adipose tissue (VAT) dysfunction contributes to non-alcoholic fatty liver disease (NAFLD) development in obesity, however, data on humans are limited. Aims of this study were to investigate the relationship between NAFLD and VAT morphofunctional impairment and to determine whether the extent of VAT remodelling is associated with liver damage and metabolic alterations in obesity. METHODS: We analysed data from 40 obese individuals candidate to bariatric surgery in whom paired intraoperative liver and omental biopsies were performed for diagnosing NAFLD and VAT inflammation by immunohistochemistry and mRNA expression studies. RESULTS: Within our study population, NAFLD was significantly associated with greater VAT CD68+ macrophages infiltration (P = .04), fibrosis (P = .04) and impaired microvascular density (P = .03) as well as increased expression of markers of local hypoxia, apoptosis and inflammation (UNC5B, CASP7, HIF1-α, IL-8, MIP2, WISP-1, all P < .01). The degree of VAT inflammation correlated with the severity of hepatic injury (steatosis, inflammation, fibrosis; all P < .01) and impaired gluco-metabolic profile. CONCLUSIONS: In obese patients, NAFLD is associated in a dose-dependent manner with signs of VAT remodelling, which reflect more severe clinical metabolic impairment. Our study depicts morphological alterations and novel mediators of VAT dysfunction, adding knowledge for future therapeutic approaches to NAFLD and its metabolic complications.
Assuntos
Tecido Adiposo , Hepatopatia Gordurosa não Alcoólica , Obesidade , Tecido Adiposo/metabolismo , Humanos , Hepatopatia Gordurosa não Alcoólica/complicações , Obesidade/metabolismo , Gravidade do PacienteRESUMO
Inflammation is strictly interconnected to anti-inflammatory mechanisms to maintain tissue homeostasis. The disruption of immune homeostasis can lead to acute and chronic inflammatory diseases, as cardiovascular, pulmonary, metabolic diseases and cancer. The knowledge of the mechanisms involved in the development and progression of these pathological conditions is important to find effective therapies. Granzyme B (GrB) is a serine protease produced by a variety of immune, non-immune and tumor cells. Apoptotic intracellular and multiple extracellular functions of GrB have been recently identified. Its capability of cleaving extracellular matrix (ECM) components, cytokines, cell receptors and clotting proteins, revealed GrB as a potential multifunctional pro-inflammatory molecule with the capability of contributing to the pathogenesis of different inflammatory conditions, including inflammaging, acute and chronic inflammatory diseases and cancer. Here we give an overview of recent data concerning GrB activity on multiple targets, potentially allowing this enzyme to regulate a wide range of crucial biological processes that play a role in the development, progression and/or severity of inflammatory diseases. We focus our attention on the promotion by GrB of perforin-dependent and perforin-independent (anoikis) apoptosis, inflammation derived by the activation of some cytokines belonging to the IL-1 cytokine family, ECM remodeling, epithelial-to-mesenchymal transition (EMT) and fibrosis. A greater comprehension of the pathophysiological consequences of GrB-mediated multiple activities may favor the design of new therapies aim to inhibit different inflammatory pathological conditions such as inflammaging and age-related diseases, EMT and organ fibrosis.