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Updated: Aug 9, 2026
Murine Myocardial Infarction Model using Permanent Ligation of Left Anterior Descending Coronary Artery
Published on: August 16, 2019
Sex-related dimorphic response of HIF-1 alpha expression in myocardial ischemia
Manuela Zampino1, Milana Yuzhakova, James Hansen
1Section of Cardiology, Center for Cardiovascular Research, Univ. of Illinois at Chicago, 840 South Wood St, M/C 787, Chicago, IL 60612, USA.
Insights
Hypoxia-inducible factor-1 alpha (HIF-1 alpha) shows a sex-dimorphic response to myocardial ischemia. Female rats exhibit significantly higher HIF-1 alpha expression and downstream target gene activation, suggesting a protective mechanism against cardiac remodeling.
Area of Science:
- Cardiovascular Biology
- Molecular Medicine
- Cellular Physiology
Background:
- Hypoxia-inducible factor-1 alpha (HIF-1 alpha) is a key regulator of cellular adaptation to low oxygen conditions.
- Sex-related differences exist in cardiac response to ischemia, with males showing greater dilation than females.
- Understanding these sex differences in HIF-1 alpha response is crucial for targeted therapies.
Purpose of the Study:
- To investigate the sex-related dimorphic response of HIF-1 alpha to myocardial ischemia.
- To elucidate the role of HIF-1 alpha in sex-specific cardiac remodeling after ischemic events.
Main Methods:
- Male and female rats underwent myocardial ischemia (coronary ligation) or sham operation.
- HIF-1 alpha expression was quantified using immunohistochemistry, Western blot, and RT-PCR at 5 and 24 hours post-ligation.
- Expression of downstream HIF target genes was also analyzed.
Main Results:
- Histochemistry revealed significantly higher HIF-1 alpha nuclear expression in female hearts (55% at 5h, 82% at 24h) compared to male hearts (33% at 5h, 49% at 24h) post-ischemia.
- Western blot showed a 60% greater increase in HIF-1 alpha protein in female hearts versus male hearts 24 hours after ischemia.
- Increased mRNA expression of HIF-1 alpha and its target genes (heme oxygenase, BNP) was observed in females compared to males.
Conclusions:
- A novel sex-dimorphic cellular mechanism involving HIF-1 alpha in response to myocardial ischemia is identified.
- Higher HIF-1 alpha activation in females may contribute to their differential response to ischemic injury and potentially reduced left ventricular remodeling.
- Modulating HIF-1 alpha presents a potential therapeutic strategy for preventing adverse cardiac remodeling after ischemia.
Abstract:
Hypoxia-inducible factor-1 alpha (HIF-1 alpha) plays a role in a number of cell-protective pathways after ischemia. There are clear sex-related differences in the remodeling process, and hearts from males tend to dilate in response to pathological loads and ischemia to a greater degree than do hearts from females. Thus we hypothesized that there would be a sex-related dimorphic response of HIF-1 alpha to an ischemic event. Male and female rats were euthanized 5 and 24 h after coronary ligation (M-MI and F-MI; MI, myocardial ischemia), and HIF-1 alpha expression was determined by immunohistochemistry, Western blot, and quantitative RT-PCR. Sham-operated male and female animals served as controls (M-SH and F-SH). In the ischemic area, histochemical analysis at 5 h showed that HIF was expressed in 33% of cell nuclei in M-MI and in 55% in F-MI. At 24 h, HIF expression increased to 49% in M-MI and to 82% in F-MI (P < 0.05 vs. SH and also M-MI vs. F-MI). This difference was not only statistically significant between the two sexes at 24 h but also within each sex at 5 and 24 h after ligation. Western blots confirmed that, at 24 h after ischemia, HIF protein increased significantly in both male and female hearts relative to sham-operated animals but that the increase in females was 60% greater than that seen in males. mRNA expression of HIF was significantly increased at 24 h in F-MI versus M-MI and sham-operated animals. Expression of downstream HIF target genes (heme oxygenase and brain natriuretic peptide) was increased in proportion to the levels of HIF expression. These data suggest a novel cellular mechanism to explain the sex-related dimorphic response to ischemia and also the possibility that exogenous modulation of HIF might represent a new therapeutic approach to preventing left ventricular remodeling.
