The possible role of hypoxia in the affected tissue of relapsed clubfoot

Abstract

Our aim was to study the expression of hypoxia-related proteins as a possible regulatory pathway in the contracted side tissue of relapsed clubfoot. We compared the expression of hypoxia-related proteins in the tissue of the contracted (medial) side of relapsed clubfoot, and in the tissue of the non-contracted (lateral) side of relapsed clubfoot. Tissue samples from ten patients were analyzed by immunohistochemistry and image analysis, Real-time PCR and Mass Spectrometry to evaluate the differences in protein composition and gene expression. We found a significant increase in the levels of smooth muscle actin, transforming growth factor-beta, hypoxia-inducible factor 1 alpha, lysyl oxidase, lysyl oxidase-like 2, tenascin C, matrix metalloproteinase-2, matrix metalloproteinase-9, fibronectin, collagen types III and VI, hemoglobin subunit alpha and hemoglobin subunit beta, and an overexpression of ACTA2, FN1, TGFB1, HIF1A and MMP2 genes in the contracted medial side tissue of clubfoot. In the affected tissue, we have identified an increase in the level of hypoxia-related proteins, together with an overexpression of corresponding genes. Our results suggest that the hypoxia-associated pathway is potentially a factor contributing to the etiology of clubfoot relapses, as it stimulates both angioproliferation and fibroproliferation, which are considered to be key factors in the progression and development of relapses.

Genetic Role in Recurrence of Idiopathic CTEV: A Systematic Review

“…The increased HIF1A gene in response to ongoing hypoxia would stimulate the production of TGFb1 as a cytokine which led to myofibroblast trans-differentiation, reflected in the raised expression of ACTA2 gene expression and its protein, SmActin. 2 Similar to the previous study result discussed by Ošťádal et al, these samples' collagen type III and VI levels on the medial clubfoot side were also increased compared to its lateral side. 17 These changes in extracellular matrix protein expression, along with their corresponding genes from these feet samples, shed light on the role of hypoxia-induced fibrotic changes within recurrent ICTEV cases.…”

“…Socioeconomic factors and familial and treatment compliance have illustrated their effects in causing relapses in some patients. 2,[9][10][11] Unfortunately, the role of genes, which had been in question for a while, has shown to be understudied, as seen by the insufficient number of studies. Genetic causes have been linked to the occurrence of idiopathic clubfoot after studies showed linkage through positive family history, twin studies, higher incidence in certain areas and gender.…”

“…Clubfoot affects 1 in every 1000 infants born worldwide, with various incidences according to geographical areas. 2 For instance, the New Zealand area, with primarily Polynesian ethnicity, reported a higher incidence number than the rest of the world. 3 Male infants tend to be more affected by this anomaly, with bilateral cases occurring more often than not.…”

“…14 The rest of the study results included in this review discussed the protein changes found in patients with recurrent ICTEV, where one of them also discussed the genes responsible for these protein expressions. 2 Ošťádal et al reported 19 different proteins found within relapsed clubfeet samples taken during surgery which were dominated by collagens type I and III as the primary component of the extracellular matrix. New findings of some significant collagen reported were collagens V, VI, and XII, and as the samples were all taken from recurrent ICTEV patients, meaning the quantity of these may correlate with the severity of ICTEV led to multiple series of casting and eventually surgery.…”

Tumour response to hypoxia: understanding the hypoxic tumour microenvironment to improve treatment outcome in solid tumours

“…Hypoxic induction of COL1 deposition has been known for 40 years and confirmed in several studies ( 142 – 145 ). Other studies also show HIF-mediated deposition and/or gene expression of fibrillar COLs (COL3 ( 146 ), COL5 ( 147 – 150 ), COL11 ( 149 , 151 ) and COL27 ( 149 )), basement membrane COLs (COL4 ( 150 , 152 , 153 ), COL7 ( 154 ), COL10 ( 151 , 155 ) and COL18 ( 153 , 156 )), filament-forming COLs (COL6 ( 146 )), fibril-associated COLs (COL9 ( 150 , 151 ), COL14 ( 157 )) and transmembrane COLs (COL13 ( 150 )). Recent studies show hypoxia can also enhance fibrosis through increasing FN expression ( 158 , 159 ).…”