Unravelling the Role of MAPKs (ERK1/2) in Venous Reflux in Patients with Chronic Venous Disorder

Chronic venous disorder (CVeD), is a disorder in which there is a modification in the conditions of blood return to the heart. The disorder may arise from incompetent valves and the resultant venous reflux (chronic venous insufficiency, CVI). The economic burden of CVeD on health systems is high, and research efforts have sought to elucidate the mechanisms involved as possible therapeutic targets. The mitogen-activated protein kinase (MAPK) enzymes mediate a wide array of physiopathological processes in human tissues. In this family of proteins, extracellular signal-regulated kinase (ERK)1/2 plays a direct role in the cell homeostasis that determines the viability of mammalian tissues. This study sought to examine whether ERK1/2 plays a role in venous reflux. This was a prospective study performed on 56 participants including 11 healthy controls. Of the CVeD patients, 23 had venous reflux with CVI (CVI-R) and 22 had no reflux (NR). Distribution by age was: controls <50 years (n = 4) and ≥50 years (n = 7); NR <50 years (n = 9) and ≥50 years (n = 13); CVI-R <50 years (n = 11) and ≥50 years (n = 12). Great saphenous vein specimens were subjected to gene (real-time polymerase chain reaction, RT-qPCR) and protein (immunohistochemistry, IHC) expression techniques to identify ERK1/2. Data was compared between groups using the Mann Whitney U test. Patients with CVI showed significant gene activation of ERK1/2 protein, and, in those with venous reflux, the expression of this gene was significantly greater. The CVI-R group <50 years showed significantly greater ERK1/2 gene expression than their age-matched controls. Expression patterns were consistent with IHC findings. Our studies suggest that ERK1/2 expression is involved in venous vascular disease.