The genetic variation rs6903956 in the novel androgen-dependent tissue factor pathway inhibitor regulating protein (ADTRP) gene is not associated with levels of plasma coagulation factors in the Singaporean Chinese

von Willebrand factor, ADAMTS-13, and thrombospondin 1 in relation to clinical outcomes in elderly patients with a recent myocardial infarction

Background

von Willebrand factor (VWF) multimers are cleaved by A disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13 (ADAMTS-13) into less active fragments. Thrombospondin 1 (TSP-1) competes with VWF's cleavage site, protecting it from degradation. Low ADAMTS-13 and high VWF have been associated with cardiovascular disease and atrial fibrillation (AF).

Objectives

We aimed to investigate whether VWF, ADAMTS-13, and TSP-1 are associated with clinical outcome.

Methods

Elderly patients with a recent myocardial infarction (MI) (n = 1027) were followed for 2 years. Blood was collected 2 to 8 weeks after the MI for ADAMTS-13, VWF, and TSP-1 measures. The primary endpoints (major adverse cardiovascular events; n = 210) included the first event of MI, stroke, heart failure hospitalization, coronary revascularization, and all-cause death. Total mortality was also registered (n = 56). The secondary endpoint was new-onset AF (n = 43).

Results

Concentrations of VWF, ADAMTS-13, and TSP-1 did not intercorrelate. The risk of major adverse cardiovascular events was altered in patients with VWF ≥ median (hazard ratio [HR], 1.4; 95% CI, 1.0-1.8; P = .03) and ADAMTS-13 ≥ median (HR, 0.7; 95% CI, 0.5-0.9; P = .02); however, it was not significant in adjusted models. VWF and ADAMTS-13 were significantly associated with total mortality, with a HR of 2.7 (95% CI, 1.6-4.6; P < .001) for VWF (Q4 vs. Q1-Q3) and HR of 0.3 (95% CI, 0.2-0.5; P < .001) for ADAMTS-13 (Q2-4 vs. Q1). The associations persisted in multivariable analysis, but the significance disappeared for VWF after correcting for high-sensitivity C-reactive protein. The risk of new-onset AF was lower in patients with VWF ≥ median (HR, 0.5; 95% CI, 0.3-1.0; P = .04]), and this was still significant after adjustments.

Conclusion

Although low ADAMTS-13 predicted death, the cardiovascular risk associated with VWF and ADAMTS-13 was weaker than previously reported. Low VWF is associated with new-onset AF and needs further research.

Androgen-dependent tissue factor pathway inhibitor regulating protein: a review of its peripheral actions and association with cardiometabolic diseases

The first genome-wide association study on coronary artery disease (CAD) in the Han Chinese population identified C6orf105 as a susceptibility gene. The C6orf105 gene was later found to encode for a protein that regulates tissue factor pathway inhibitor (TFPI) expression in endothelial cells in an androgen-dependent manner, and the novel protein was thus termed androgen-dependent TFPI-regulating protein (ADTRP). Since the identification of ADTRP, there have been several studies associating genetic variants on the ADTRP gene with CAD risk, as well as research providing mechanistic insights on this novel protein and its functional role. ADTRP is a membrane protein, whose expression is upregulated by androgen, GATA-binding protein 2, oxidized low-density lipoprotein, peroxisome proliferator-activated receptors, and low-density lipoprotein receptors. ADTRP regulates multiple downstream targets involved in coagulation, inflammation, endothelial function, and vascular integrity. In addition, ADTRP functions as a fatty acid esters of hydroxy fatty acid (FAHFA)-specific hydrolase that is involved in energy metabolism. Current evidence suggests that ADTRP may play a role in the pathogenesis of atherosclerosis, CAD, obesity, and metabolic disorders. This review summarizes the current literature on ADTRP, with a focus on the peripheral actions of ADTRP, including expression, genetic variations, signaling pathways, and function. The evidence linking ADTRP and cardiometabolic diseases will also be discussed.

Acute myocardial infarction associated with thrombotic microangiopathy following a hump-nosed viper bite: a case report

BACKGROUND

Hump-nosed viper bite is the commonest cause of venomous snakebite in Sri Lanka. Despite initially being considered a moderately venomous snake more recent reports have revealed that it could cause significant systemic envenoming leading to coagulopathy and acute kidney injury. However, myocardial infarction was not reported except for a single case, which occurred immediately after the snakebite.

CASE PRESENTATION

A 50-year-old previously healthy Sri Lankan woman had a hump-nosed viper bite with no evidence of systemic envenoming during initial hospital stay. Five days later she presented with bite site cellulitis with hemorrhagic blisters, acute kidney injury, and evidence of microangiopathic hemolytic anemia and thrombocytopenia with normal coagulation studies. She was managed with supportive care that included intravenously administered antibiotics, blood transfusions, and hemodialysis; both her microangiopathic hemolytic anemia and thrombocytopenia improved without any specific intervention. On day 10 she developed: a non-ST elevation myocardial infarction complicated with acute left ventricular failure evidenced by acute shortness of breath with desaturation despite adequate ultrafiltration; new onset lateral lead T inversions in electrocardiogram; raised troponin I titer; and hypokinetic segments on echocardiogram. She was managed with low molecular weight heparin and antiplatelet drugs, which were later discontinued due to upper gastrointestinal bleeding. Her hospital stay was further complicated by hospital-acquired pneumonia and deep vein thrombosis involving her ileofemoral vein. She died on day 33 from the snakebite.

CONCLUSIONS

Myocardial infarction after snakebites is rarely reported. This is the first case report of a patient developing a myocardial infarction during the recovery phase of thrombotic microangiopathy following a hump-nosed viper bite. The possibility of thrombotic risk related to thrombotic microangiopathy following hump-nosed viper bite is an area that is poorly studied; it needs further attention.