Left ventricular dysfunction and associated cellular injury in rats exposed to chronic intermittent hypoxia

2008 ◽  
Vol 104 (1) ◽  
pp. 218-223 ◽  
Author(s):  
Ling Chen ◽  
Jin Zhang ◽  
Tracey X. Gan ◽  
Ye Chen-Izu ◽  
Jeffrey D. Hasday ◽  
...  
Keyword(s):  
Intermittent Hypoxia ◽  
Pressure Rise ◽  
Left Ventricular ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Chronic Intermittent Hypoxia ◽  
Cellular Injury ◽  
Maximal Rate ◽  
Gene Markers ◽  
Obstructive Sleep ◽  
Cardiovascular Morbidity And Mortality

Obstructive sleep apnea (OSA) increases cardiovascular morbidity and mortality. We have reported that chronic intermittent hypoxia (CIH), a direct consequence during OSA, leads to left ventricular (LV) remodeling and dysfunction in rats. The present study is to determine LV myocardial cellular injury that is possibly associated with LV global dysfunction. Fifty-six rats were exposed either to CIH (nadir O2 4–5%) or sham (handled normoxic controls, HC), 8 h/day for 6 wk. At the end of the exposure, we studied LV global function by cardiac catheterization, and LV myocardial cellular injury by in vitro analyses. Compared with HC, CIH animals demonstrated elevations in mean arterial pressure and LV end-diastolic pressure, but reductions in cardiac output (CIH 141.3 ± 33.1 vs. HC 184.4 ± 21.2 ml·min−1·kg−1, P < 0.01), maximal rate of LV pressure rise in systole (+dP/d t), and maximal rate of LV pressure fall in diastole (−dP/d t). CIH led to significant cell injury in the left myocardium, including elevated LV myocyte size, measured by cell surface area (CIH 3,564 ± 354 vs. HC 2,628 ± 242 μm2, P < 0.05) and cell length (CIH 148 ± 23 vs. HC 115 ± 16 μm, P < 0.05), elevated terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-stained positive cell number (CIH 98 ± 45 vs. HC 15 ± 13, P < 0.01), elevated caspase-3 activity (906 ± 249 vs. 2,275 ± 1,169 pmol·min−1·mg−1, P < 0.05), and elevated expression of several remodeling gene markers, including c-fos, atrial natriuretic peptide, β-myosin heavy chain, and myosin light chain-2. However, there was no difference between groups in sarcomere contractility of isolated LV myocytes, or in LV collagen deposition on trichrome-stained slices. In conclusion, CIH-mediated LV global dysfunction is associated with myocyte hypertrophy and apoptosis at the cellular level.

scholarly journals The Na+/Ca2+ exchanger-1 mediates left ventricular dysfunction in mice with chronic intermittent hypoxia

2010 ◽  
Vol 109 (6) ◽  
pp. 1675-1685 ◽  
Author(s):  
Ling Chen ◽  
Jin Zhang ◽  
Xuejiao Hu ◽  
Kenneth D. Philipson ◽  
Steven M. Scharf
Keyword(s):  
Blood Pressure ◽  
Intermittent Hypoxia ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Heart Weight ◽  
Chronic Intermittent Hypoxia ◽  
Lv Dysfunction ◽  
Obstructive Sleep ◽  
Lower Ejection Fraction

Chronic intermittent hypoxia (CIH) and cardiovascular dysfunction occur in patients with obstructive sleep apnea. We hypothesized that the Na+/Ca2+ exchanger-1 (NCX1) mediates, at least partially, left ventricular (LV) dysfunction in CIH. Four groups of mice ( N = 15–17 per group), either cardiac-specific NCX1 knockouts (KO) or wild types (WT), were exposed to either CIH or normoxia [i.e., handled controls (HC)] 10 h/day for 8 wk. As expected, myocardial expression of NCX1 was greater in WT than in KO animals, both in HC and CIH-exposed groups. In both CIH groups (WT or KO), but not the HC groups, blood pressure increased by 10% at week 1 over their baseline and remained elevated for all 8 wk, with no differences between WT and KO. LV dilation (increased diastolic and systolic dimension) and hypertrophy (increased left heart weight), along with LV dysfunction (greater end-diastolic pressure and lower ejection fraction), were observed in the WT animals compared with the KO following CIH exposure. Compared with HC, CIH exposure was associated with apoptosis (terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling and caspase-3) in WT, but not KO, mice. We conclude that myocardial NCX1 does not mediate changes in blood pressure, but is one of the mediators for LV global dysfunction and cardiomyocyte injury in CIH.

scholarly journals Intermittent hypoxia in utero damages postnatal growth and cardiovascular function in rats

2018 ◽  
Vol 124 (4) ◽  
pp. 821-830 ◽  
Author(s):  
Ling Chen ◽  
Zahra Heidari Zadi ◽  
Jin Zhang ◽  
Steven M. Scharf ◽  
Eung-Kwon Pae
Keyword(s):  
Blood Pressure ◽  
Obstructive Sleep Apnea ◽  
Body Weight ◽  
Sleep Apnea ◽  
Intermittent Hypoxia ◽  
Cardiovascular Function ◽  
Left Ventricular ◽  
Chronic Intermittent Hypoxia ◽  
Tibial Length ◽  
Obstructive Sleep

Obstructive sleep apnea (OSA) is common in pregnancy and may compromise fetal and even postnatal development. We developed an animal model to determine if maternal OSA could have lasting effects in offspring. Pregnant Sprague-Dawley rats were exposed to reduced ambient O2 from 21 to 4–5%, approximately once per minute [chronic intermittent hypoxia (CIH)] for 8 h/day during gestation days 3–19. Similarly handled animals exposed to ambient air served as controls (HC). Offspring were studied for body growth and cardiovascular function for 8 postnatal weeks. Compared with HC, prenatal CIH led to growth restriction, indicated by smaller body weight and tibial length, and higher arterial blood pressure in both male and female offspring. Compared with same-sex HC, CIH males showed abdominal obesity (greater ratio of abdominal fat weight to body weight or tibial length), left ventricular (LV) hypertrophy (greater heart weight-to-tibial length ratio and LV posterior wall diastolic thickness), elevated LV contractility (increases in LV ejection fraction, end-systolic pressure-volume relations, and preload recruitable stroke work), elevated LV and arterial stiffness (increased end-diastolic pressure-volume relationship and arterial elasticity), and LV oxidative stress (greater lipid peroxide content). Compared with female CIH offspring, male CIH offspring had more profound changes in blood pressure (BP), cardiac function, myocardial lipid peroxidase (LPO) content, and abdominal adiposity. Rodent prenatal CIH exposure, mimicking human maternal OSA, exerts detrimental morphological and cardiovascular effects on developing offspring; the model may provide useful insights of OSA effects in humans. NEW & NOTEWORTHY Obstructive sleep apnea is common in human pregnancy. Following maternal exposure to chronic intermittent hypoxia, a hallmark of sleep apnea, both sexes of rat offspring showed growth retardation, with males being more vulnerable to hypertension and dysfunctional left ventricular changes. This model is useful to study detrimental effects of maternal obstructive sleep apnea on developing offspring in humans.

scholarly journals Vascular and renal telomere shortening in mice exposed to chronic intermittent hypoxia

2021 ◽  
Author(s):  
Mohammad Badran ◽  
Bisher Abuyassin ◽  
Najib Ayas ◽  
Don D. Sin ◽  
Ismail Laher
Keyword(s):  
Obstructive Sleep Apnea ◽  
Chronic Condition ◽  
Intermittent Hypoxia ◽  
Kidney Diseases ◽  
Chronic Intermittent Hypoxia ◽  
Telomere Shortening ◽  
Chronic Kidney Diseases ◽  
Biomarkers Of Aging ◽  
Obstructive Sleep ◽  
Renal Aging

AbstractObstructive sleep apnea (OSA) is a chronic condition characterized by chronic intermittent hypoxia (IH) and is associated with cardiovascular (CVD) and chronic kidney diseases (CKD). There is increased biomarkers of aging, such as telomere shortening, in patients with OSA. We assessed telomere lengths in aortic and renal tissues from mice exposed to 8 weeks of IH using a PCR protocol, and demonstrate significant telomere shortening in both tissues. This data indicates that IH, a hallmark of OSA, can accelerate vascular and renal aging that may contribute to OSA-induced CVD and CKD

scholarly journals Tempol Alleviates Chronic Intermittent Hypoxia-Induced Pancreatic Injury Through Repressing Inflammation and Apoptosis

2019 ◽  
pp. 445-455
Author(s):  
Y. WANG ◽  
L. AI ◽  
B. HAI ◽  
Y. CAO ◽  
R. LI ◽  
...  
Keyword(s):  
Intermittent Hypoxia ◽  
Pancreatic Injury ◽  
Protective Role ◽  
Pancreatic Tissue ◽  
Mitogen Activated Protein Kinase ◽  
Chronic Intermittent Hypoxia ◽  
Obstructive Sleep ◽  
Mitogen Activated Protein ◽  
Induced Apoptosis ◽  
Oxide Synthase

Obstructive sleep apnea (OSA) has been demonstrated to be implicated in disorder of insulin secretion and diabetes mellitus. In this study, we aimed to evaluate the protective role of tempol, a powerful antioxidant, in chronic intermittent hypoxia (IH)-induced pancreatic injury. The rat model of OSA was established by IH exposure. The pathological changes, increased blood-glucose level, and raised proinsulin/insulin ratio in pancreatic tissues of rats received IH were effectively relieved by tempol delivery. In addition, the enhanced levels of pro-inflammatory cytokines, TNF-α, IL-1β, IL-6, and inflammatory mediators, PGE2, cyclooxygenase-2 (COX-2), NO, and inducible nitric oxide synthase (iNOS) in pancreatic tissue were suppressed by tempol. Moreover, tempol inhibited IH-induced apoptosis in pancreatic tissue as evidenced by upregulated Bcl-2 level, and downregulated Bax and cleaved caspase-3 levels. Finally, the abnormal activation of mitogen-activated protein kinase (MAPK) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways induced by IH was restrained by tempol administration. In summary, our study demonstrates that tempol relieves IH-induced pancreatic injury by inhibiting inflammatory response and apoptosis, which provides theoretical basis for tempol as an effective treatment for OSA-induced pancreatic injury.

Left ventricular function and remodelling in rats exposed stepwise up to extreme chronic intermittent hypoxia

2020 ◽  
Vol 282 ◽  
pp. 103526
Author(s):  
František Papoušek ◽  
David Sedmera ◽  
Jan Neckář ◽  
Bohuslav Ošťádal ◽  
František Kolář
Keyword(s):  
Left Ventricular Function ◽  
Ventricular Function ◽  
Intermittent Hypoxia ◽  
Left Ventricular ◽  
Chronic Intermittent Hypoxia
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