Prolonged Mechanical Stretch is Associated with Upregulation of Hypoxia-inducible Factors and Reduced Contraction in Rat Inferior Vena Cava

Abstract

Results: Acute DVT occurred in 7.3%, and chronic DVT occurred in 9.7% of patients studied (24.0% inpatients, 60.9% female; mean age, 56.3 years [range, 4-91 years, 1.1% aged Ͻ16 years]). History of previous DVT (74.0%) and smoking (38.0%) were the most common risk factors in patients with DVT. Iliac DVT was identified in 9.6% of acute DVT and in 5.7% of chronic DVT. Common femoral DVT was identified in 30.8% of acute DVT and in 22.9% of chronic DVT. CDL was used in 14.3% and thrombectomy in 4.8% of acute iliac/common femoral DVT and was never used with distal DVT. Warfarin anticoagulation with or without heparin/enoxaparin overlap was the most common treatment for acute (58.5%) and chronic (48.6%) iliac/common femoral DVT. In 2008 the referral base of the IU laboratory increased significantly. Acute DVT occurred significantly less often during the 1-year period of 2008 (5.3%) than in the 10-year period 1998 to 2007 (7.6%), but iliac/common femoral DVT as a component of acute DVT did not differ significantly (40.0% in 2008, 41.9% in 1998-2007).Conclusions: Iliac/common femoral DVT affects almost half of patients with acute DVT. Current recommendations of acute thrombus removal for the treatment of iliofemoral DVT is under-utilized, suggesting that perhaps greater education of clinicians and patients regarding invasive therapy for iliofemoral DVT is necessary.

Daily muscle stretching enhances blood flow, endothelial function, capillarity, vascular volume and connectivity in aged skeletal muscle

“…) and prolonged stretch in isolated vessels (Lim et al . ). Vascular endothelial cells sense extracellular mechanical stimuli such as shear stress and stretch and then transduce these signals into intracellular signalling cascades that trigger angiogenesis even under nonhypoxic conditions (Holly et al .…”

“…A more probable mechanism driving the upregulation of HIF-1α in the present study is the prolonged mechanical deformation of the blood vessels associated with sustained muscle stretch. Specifically, HIF-1α expression is increased with cyclical mechanical stretch in vascular smooth muscle cells (Chang et al 2003) and prolonged stretch in isolated vessels (Lim et al 2011). Vascular endothelial cells sense extracellular mechanical stimuli such as shear stress and stretch and then transduce these signals into intracellular signalling cascades that trigger angiogenesis even under nonhypoxic conditions (Holly et al 1980;Hoier et al 2010).…”

Management of venous leg ulcers: Clinical practice guidelines of the Society for Vascular Surgery® and the American Venous Forum

“…66,67 MMPs have been demonstrated in rat venous tissue to cause venous dilation by several mechanisms, including hyperpolarization and inhibition of extracellular calcium mobilization, which are tightly regulated by hypoxia-inducible factor (HIF). [68][69][70] In a study evaluating varicose veins in CVD patients, it was determined that HIF-1a and HIF-2a transcriptional factors were overexpressed compared with control nonvaricose veins, suggesting that the HIF pathway may be associated with several pathophysiologic changes in the venous wall leading to venous hypertension and that hypoxia may be a feature contributing to the pathogenesis of varicose veins. 70 MMPs have been found to be present in high quantities in VLUs and the associated wound fluid, and there is a correlation of increased expression of proteinase activity with poor healing.…”

Mechanical Stretch Upregulates SDF-1α in Skin Tissue and Induces Migration of Circulating Bone Marrow-Derived Stem Cells into the Expanded Skin

“…The upregulation of SDF‐1α following mechanical stretching of skin may arise from induction of hypoxia inducible factor‐1α (HIF‐1α). Increased expression of HIF‐1α in response to mechanical stretching has been reported for vascular smooth muscle cells , myocardial cells , skeletal muscle fibers , and fibroblasts . Mechanical stretching can be sensed by cell membrane ion channels, integrins, and receptor tyrosine kinases .…”