Correlation between Serum Fatty Acid Binding Protein 4 (FABP4) Levels and Cardiac Function in Patients with Thalassemia Major

Adipocyte fatty acid-binding protein (FABP4) as a potential biomarker for predicting metabolically driven low-grade and organ damage in thalassemia syndromes

Adipocyte fatty acid-binding protein (A-FABP; FABP4) plays a significant role in the pathogenesis and progression of metabolically driven low-grade inflammation and organ damage. This study aimed to evaluate the performance of circulating FABP4 as a predictive and diagnostic biomarker for thalassemia-associated cardiometabolic events. This case-control study enrolled 50 adults with β-thalassemia and 30 age-, sex-, and body mass index-matched controls. Participants underwent a comprehensive evaluation, including complete blood count, liver and kidney function tests, serum blood glucose, lipid profile, and ferritin levels, pelviabdominal ultrasound, ECG, and echocardiography after taking a full medical history and conducting a clinical examination. Serum levels of FABP4 were measured using an Enzyme-Linked-Immunosorbent-Assay. The diagnostic performance of FABP4 was assessed using receiver operator characteristic (ROC) curve analysis to determine optimal values for excluding and confirming cardiometabolic metflammation. The thalassemia cohort exhibited a statistically significant higher concentration of FABP4 compared to the control group (p-value < 0.001). Positive correlations were found between FABP4 and ferritin serum levels above 800 or 1000 ug/L, as well as with ALT, TGS, and LDL (p-value < 0.05). Circulating FABP4 was identified as a statistically significant risk factor for thalassemia-associated cardiometabolic comorbidities (OR = 84.00, 95%CI:18.6-378.6, p-value < 0.001). ROC analysis determined that the FABP4 exclusionary cut-off value > 2.30 ng/ml could effectively discriminate between thalassemia-associated adverse metaflammation and controls, while the FABP4 confirmatory cut-off value was > 2.58 ng/ml. In conclusion, circulating FABP4 appears to be a potential risk factor for predicting progression to cardiometabolic events in thalassemia-associated adverse metaflammation. FABP4 holds promise as a diagnostic and prognostic biomarker for disease monitoring and risk stratification. Further validation through large-scale, multicenter, prospective studies is warranted.

Adipose knockout of H-ferritin improves energy metabolism in mice

OBJECTIVE

Ferritin, the principal iron storage protein, is essential to iron homeostasis. How iron homeostasis affects the adipose tissue is not well understood. We investigated the role of ferritin heavy chain in adipocytes in energy metabolism.

METHODS

We generated adipocyte-specific ferritin heavy chain (Fth, also known as Fth1) knockout mice, herein referred to as FthAKO. These mice were analyzed for iron homeostasis, oxidative stress, mitochondrial biogenesis and activity, adaptive thermogenesis, insulin sensitivity, and metabolic measurements. Mouse embryonic fibroblasts and primary mouse adipocytes were used for in vitro experiments.

RESULTS

In FthAKO mice, the adipose iron homeostasis was disrupted, accompanied by elevated expression of adipokines, dramatically induced heme oxygenase 1(Hmox1) expression, and a notable decrease in the mitochondrial ROS level. Cytosolic ROS elevation in the adipose tissue of FthAKO mice was very mild, and we only observed this in the brown adipose tissue (BAT) but not in the white adipose tissue (WAT). FthAKO mice presented an altered metabolic profile and showed increased insulin sensitivity, glucose tolerance, and improved adaptive thermogenesis. Interestingly, loss of ferritin resulted in enhanced mitochondrial respiration capacity and a preference for lipid metabolism.

CONCLUSIONS

These findings indicate that ferritin in adipocytes is indispensable to intracellular iron homeostasis and regulates systemic lipid and glucose metabolism.