FGF21 contributes to metabolic improvements elicited by combination therapy with exenatide and pioglitazone in patients with type 2 diabetes

Association of inflammatory cytokines with type 2 diabetes mellitus and diabetic nephropathy: a bidirectional Mendelian randomization study

Objective

Previous observational studies have suggested associations between various inflammatory cytokines with type 2 diabetes mellitus and diabetic nephropathy. However, the causal association remains uncertain.

Method

Summary statistics for type 2 diabetes mellitus and diabetic nephropathy were obtained from a publicly available genome-wide association study. Data on inflammatory cytokines were sourced from a genome-wide association study on protein quantitative trait loci. The inverse variance-weighted method was applied as the primary method for causal inference. MR-Egger, weighted mode, and weighted median method were employed as supplementary analyses. Sensitivity analyses were performed to detect heterogeneity and potential horizontal pleiotropy in the study.

Result

Genetic evidence indicated that elevated levels of fibroblast growth factor 19 levels promoted the occurrence of type 2 diabetes mellitus, and increased concentrations of fibroblast growth factor 21 levels, C-C motif chemokine 19 levels, eotaxin levels, and interleukin-10 mitigated the risk of developing type 2 diabetes mellitus, while type 2 diabetes mellitus did not exert a significant influence on said proteins. Elevated levels of tumor necrosis factor ligand superfamily member 14 and TNF-related activation-induced cytokine were associated with an increased risk of diabetic nephropathy, and increased concentrations of interleukin-1-alpha and transforming growth factor-alpha were potentially correlated with a diminished risk of diabetic nephropathy. Sensitivity analyses further ensure the robustness of our findings.

Conclusion

Mendelian randomization analysis highlights a causal association between inflammatory cytokines with type 2 diabetes mellitus and diabetic nephropathy, offering valuable evidence and reference for future research.

Exploring omics signature in the cardiovascular response to semaglutide: Mechanistic insights and clinical implications

BACKGROUND

Semaglutide, a glucagon-like peptide-1 (GLP-1) receptor agonist, is a widely used drug for the treatment of type 2 diabetes that offers significant cardiovascular benefits.

RESULTS

This review systematically examines the proteomic and metabolomic indicators associated with the cardiovascular effects of semaglutide. A comprehensive literature search was conducted to identify relevant studies. The review utilizes advanced analytical technologies such as mass spectrometry and nuclear magnetic resonance (NMR) to investigate the molecular mechanisms underlying the effects of semaglutide on insulin secretion, weight control, anti-inflammatory activities and lipid metabolism. These "omics" approaches offer critical insights into metabolic changes associated with cardiovascular health. However, challenges remain such as individual variability in expression, the need for comprehensive validation and the integration of these data with clinical parameters. These issues need to be addressed through further research to refine these indicators and increase their clinical utility.

CONCLUSION

Future integration of proteomic and metabolomic data with artificial intelligence (AI) promises to improve prediction and monitoring of cardiovascular outcomes and may enable more accurate and effective management of cardiovascular health in patients with type 2 diabetes. This review highlights the transformative potential of integrating proteomics, metabolomics and AI to advance cardiovascular medicine and improve patient outcomes.

Association of circulating inflammatory proteins with type 2 diabetes mellitus and its complications: a bidirectional Mendelian randomization study

Background

Increasing evidence indicates that immune response underlies the pathology of type 2 diabetes (T2D). Nevertheless, the specific inflammatory regulators involved in this pathogenesis remain unclear.

Methods

We systematically explored circulating inflammatory proteins that are causally associated with T2D via a bidirectional Mendelian randomization (MR) study and further investigated them in prevalent complications of T2D. Genetic instruments for 91 circulating inflammatory proteins were derived from a genome-wide association study (GWAS) that enrolled 14,824 predominantly European participants. Regarding the summary-level GWASs of type 2 diabetes, we adopted the largest meta-analysis of European population (74,124 cases vs. 824,006 controls) and a prospective nested case-cohort study in Europe (9,978 cases vs. 12,348 controls). Summary statistics for five complications of T2D were acquired from the FinnGen R9 repository. The inverse variance-weighted method was applied as the primary method for causal inference. MR-Egger, weighted median and maximum likelihood methods were employed as supplementary analyses. Results from the two T2D studies were combined in a meta-analysis. Sensitivity analyses and phenotype-wide association studies (PheWAS) were performed to detect heterogeneity and potential horizontal pleiotropy in the study.

Results

Genetic evidence indicated that elevated levels of TGF-α (OR = 1.16, 95% CI = 1.15-1.17) and CX3CL1 (OR = 1.30, 95% CI = 1.04-1.63) promoted the occurrence of T2D, and increased concentrations of FGF-21 (OR = 0.87, 95% CI = 0.81-0.93) and hGDNF (OR = 0.96, 95% CI = 0.95-0.98) mitigated the risk of developing T2D, while type 2 diabetes did not exert a significant influence on said proteins. Elevated levels of TGF-α were associated with an increased risk of ketoacidosis, neurological complications, and ocular complications in patients with T2D, and increased concentrations of FGF-21 were potentially correlated with a diminished risk of T2D with neurological complications. Higher levels of hGDNF were associated with an increased risk of T2D with peripheral vascular complications, while CX3CL1 did not demonstrate a significant association with T2D complications. Sensitivity analyses and PheWAS further ensure the robustness of our findings.

Conclusion

This study determined four circulating inflammatory proteins that affected the occurrence of T2D, providing opportunities for the early prevention and innovative therapy of type 2 diabetes and its complications.

Metformin Improves the Prerequisites for FGF21 Signaling in Patients With Type 2 Diabetes

CONTEXT

Fibroblast growth factor (FGF) 21 acts as a metabolic regulator and its therapeutic use is under investigation. FGF21 signaling requires binding to surface receptors, FGFR1c and β-klotho. FGF21 resistance is observed in metabolic diseases and FGF21 signaling is regulated by fibroblast activation protein (FAP). Metformin is reported to influence expression and secretion of FGF21 in preclinical models, but the effect of metformin on FGF21 in a clinical trial remains unknown.

OBJECTIVE

To investigate how 12 weeks of treatment with metformin affects the FGF21 signaling pathway in patients with type 2 diabetes (T2D).

METHODS

Randomized, placebo-controlled study in patients with T2D (n = 24) receiving either metformin (1000 mg twice daily) or placebo. A control group of body mass index- and age-matched healthy individuals (n = 12) received a similar dose of metformin. Blood samples and muscle and fat biopsies were collected at study entry and after 12 weeks.

METHODS

Plasma levels of FGF21 (total and intact) and FAP (total and activity) were measured. Muscle and fat biopsies were analyzed for mRNA and protein expression of targets relevant for activation of the FGF21 signaling pathway.

RESULTS

Circulating FAP activity decreased after metformin treatment compared with placebo (P = .006), whereas FGF21 levels were unchanged. Metformin treatment increased gene and protein expression of β-klotho, FGFR1c, and pFGFR1c in adipose tissue. FGF21 mRNA expression increased in muscle tissue after metformin and the FGF21 protein, but not mRNA levels, were observed in adipose tissue.

CONCLUSION

Our findings suggest that metformin suppresses the circulating FAP activity and upregulates the expression of FGFR1c and β-klotho for increased FGF21 signaling in adipose tissue, thus improving peripheral FGF21 sensitivity.

Inter-organ crosstalk during development and progression of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is characterized by tissue-specific insulin resistance and pancreatic β-cell dysfunction, which result from the interplay of local abnormalities within different tissues and systemic dysregulation of tissue crosstalk. The main local mechanisms comprise metabolic (lipid) signalling, altered mitochondrial metabolism with oxidative stress, endoplasmic reticulum stress and local inflammation. While the role of endocrine dysregulation in T2DM pathogenesis is well established, other forms of inter-organ crosstalk deserve closer investigation to better understand the multifactorial transition from normoglycaemia to hyperglycaemia. This narrative Review addresses the impact of certain tissue-specific messenger systems, such as metabolites, peptides and proteins and microRNAs, their secretion patterns and possible alternative transport mechanisms, such as extracellular vesicles (exosomes). The focus is on the effects of these messengers on distant organs during the development of T2DM and progression to its complications. Starting from the adipose tissue as a major organ relevant to T2DM pathophysiology, the discussion is expanded to other key tissues, such as skeletal muscle, liver, the endocrine pancreas and the intestine. Subsequently, this Review also sheds light on the potential of multimarker panels derived from these biomarkers and related multi-omics for the prediction of risk and progression of T2DM, novel diabetes mellitus subtypes and/or endotypes and T2DM-related complications.

Increased circulating FGF21 level predicts the burden of metabolic demands and risk of vascular diseases in adults with type 2 diabetes

OBJECTIVES

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by chronic hyperglycemia and metabolic stress, involved in the stepwise development of cardiovascular complications. Fibroblast growth factor 21 (FGF21) is a novel hepatokine involved in regulating glucose and lipid metabolism, and has been linked to the prediction, treatment, and improvement of prognosis in multiple cardiovascular diseases (CVDs). The aim of this study is to explore the relationship between FGF21 levels and vascular diseases (VDs) including carotid atherosclerosis (CAS) and hypertension (HP) in patients with T2DM.

METHODS

Baseline serum FGF21 was determined in a cross-sectional study of 701 patients with T2DM and 258 healthy control.

RESULTS

The morbidity of CAS was increased in T2DM patients with HP as compared with those without (p < 0.001). The average serum FGF21 level of healthy was [123.9 (67.2-219.3)]. Baseline FGF21 was significantly higher in those who developed CAS or HP than in those who did not [305.9 (177.2-508.4) vs. 197.2 (129.7-308.3) pg/mL, p < 0.001]. In addition, an elevated serum FGF21 was observed in T2DM patients with HP and CAS than that of T2DM patients with CAS or HP [550.5 (312.6-711.3) vs. 305.9 pg/mL, p < 0.001]. Serum FGF21 levels were positively correlated with body mass index and carotid intima media thicknes (p < 0.05), the association remained significant after adjusting for age and T2DM duration. Furthermore, the multinomial logistic regression showed that serum FGF21 was independently associated with CAS and HP in patients with T2DM after adjustment for demographic and traditional VDs risk factors (p < 0.001).

CONCLUSIONS

Baseline FGF21 is elevated in VDs during diabetes, changes of serum FGF21 levels were appropriately matched to metabolic stress. FGF21can be used as an independent predictor for diagnosing VDs and predicting prognosis.

Higher fasting fibroblast growth factor 21 was associated with a greater decline in postprandial blood pressure

BACKGROUND

A fall in blood pressure (BP) following a meal is well known and is usually a transient phenomenon, due to appropriate cardiovascular adjustments. Older individuals and those with high BP experience a greater postprandial fall that can manifest as postprandial hypotension (PPH). Fibroblast growth factor 21 (FGF21) is positively associated with BP, and is known to increase after meal ingestion. We explored whether fasting FGF21 or its postprandial change would be associated with meal induced BP change, after accounting for several covariates.

METHODS

Eighty-three Western Australian adults were studied. Supine resting BP was recorded and an oral glucose test was administered. Serial measurements of systolic BP (SBP) and diastolic BP (DBP) were then made in duplicate every 30 min up to 120 min. Fasting and 120 min blood samples were analysed for FGF21 and clinical chemistry. Multiple linear regression analyses of the incremental area under curve of postprandial SBP and DBP was conducted on 12 known determinants.

RESULTS

The final parsimonious model based on backward regression of postprandial SBP included fasting SBP, gender, fasting insulin and fasting FGF21 (β = -0.009 (95% confidence interval (CI): 0.017, -0.002, P = 0.015)). For postprandial DBP these included fasting DBP, gender, fasting glucose, fasting insulin and fasting FGF21 (β = -0.005; 95% CI: 0.010, -0.001, P = 0.021).

CONCLUSIONS

A higher fasting FGF21, independent of glucose and insulin, was associated with a greater postprandial decline in SBP and in DBP.