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Bose K, Espinoza HM, Louey S, Jonker SS. Sensitivity and activation of endoplasmic reticulum stress response and apoptosis in the perinatal sheep heart. Am J Physiol Heart Circ Physiol 2024; 327:H1-H11. [PMID: 38700493 DOI: 10.1152/ajpheart.00043.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 04/26/2024] [Accepted: 04/28/2024] [Indexed: 05/05/2024]
Abstract
Although the unfolded protein response (UPR) contributes to survival by removing misfolded proteins, endoplasmic reticulum (ER) stress also activates proapoptotic pathways. Changed sensitivity to normal developmental stimuli may underlie observed cardiomyocyte apoptosis in the healthy perinatal heart. We determined in vitro sensitivity to thapsigargin in sheep cardiomyocytes from four perinatal ages. In utero cardiac activation of ER stress and apoptotic pathways was determined at these same ages. Thapsigargin-induced phosphorylation of eukaryotic initiation factor 2 (EIF2A) was decreased by 72% between 135 and 143 dGA (P = 0.0096) and remained low at 1 dPN (P = 0.0080). Conversely, thapsigargin-induced caspase cleavage was highest around the time of birth: cleaved caspase 3 was highest at 1 dPN (3.8-fold vs. 135 dGA, P = 0.0380; 7.8-fold vs. 5 dPN, P = 0.0118), cleaved caspase 7 and cleaved caspase 12 both increased between 135 and 143 dGA (25-fold and 6.9-fold respectively, both P < 0.0001) and remained elevated at 1 dPN. Induced apoptosis, measured by TdT-mediated dUTP nick-end labeling (TUNEL) assay, was highest around the time of birth (P < 0.0001). There were changes in myocardial ER stress pathway components in utero. Glucose (78 kDa)-regulated protein (GRP78) protein levels were high in the fetus and declined after birth (P < 0.0001). EIF2A phosphorylation was profoundly depressed at 1 dPN (vs. 143 dGA, P = 0.0113). In conclusion, there is dynamic regulation of ER proteostasis, ER stress, and apoptosis cascade in the perinatal heart. Apoptotic signaling is more readily activated in fetal cardiomyocytes near birth, leading to widespread caspase cleavage in the newborn heart. These pathways are important for the regulation of normal maturation in the healthy perinatal heart.NEW & NOTEWORTHY Cardiomyocyte apoptosis occurs even in the healthy, normally developing perinatal myocardium. As cardiomyocyte number is a critical contributor to heart health, the sensitivity of cardiomyocytes to endoplasmic reticulum stress leading to apoptosis is an important consideration. This study suggests that the heart has less robust protective mechanisms in response to endoplasmic reticulum stress immediately before and after birth, and that more cardiomyocyte death can be induced by stress in this period.
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Affiliation(s)
- Karthikeyan Bose
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Herbert M Espinoza
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Samantha Louey
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Sonnet S Jonker
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon, United States
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Piccolo B, Chen A, Louey S, Thornburg K, Jonker S. Physiological response to fetal intravenous lipid emulsion. Clin Sci (Lond) 2024; 138:117-134. [PMID: 38261523 PMCID: PMC10876438 DOI: 10.1042/cs20231419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/08/2024] [Accepted: 01/23/2024] [Indexed: 01/25/2024]
Abstract
In preterm neonates unable to obtain sufficient oral nutrition, intravenous lipid emulsion is life-saving. The contribution of post-conceptional level of maturation to pathology that some neonates experience is difficult to untangle from the global pathophysiology of premature birth. In the present study, we determined fetal physiological responses to intravenous lipid emulsion. Fetal sheep were given intravenous Intralipid 20® (n = 4 females, 7 males) or Lactated Ringer's Solution (n = 7 females, 4 males) between 125 ± 1 and 133 ± 1 d of gestation (term = 147 d). Manufacturer's recommendation for premature human infants was followed: 0.5-1 g/kg/d initial rate, increased by 0.5-1 to 3 g/kg/d. Hemodynamic parameters and arterial blood chemistry were measured, and organs were studied postmortem. Red blood cell lipidomics were analyzed by LC-MS. Intravenous Intralipid did not alter hemodynamic or most blood parameters. Compared with controls, Intralipid infusion increased final day plasma protein (P=0.004; 3.5 ± 0.3 vs. 3.9 ± 0.2 g/dL), albumin (P = 0.031; 2.2 ± 0.1 vs. 2.4 ± 0.2 g/dL), and bilirubin (P<0.001; conjugated: 0.2 ± 0.1 vs. 0.6 ± 0.2 mg/dL; unconjugated: 0.2 ± 0.1 vs. 1.1 ± 0.4 mg/dL). Circulating IGF-1 decreased following Intralipid infusion (P<0.001; 66 ± 24 vs. 46 ± 24 ng/mL). Compared with control Oil Red O liver stains (median score 0), Intralipid-infused fetuses scored 108 (P=0.0009). Lipidomic analysis revealed uptake and processing of infused lipids into red blood cells, increasing abundance of saturated fatty acids. The near-term fetal sheep tolerates intravenous lipid emulsion well, although lipid accumulates in the liver. Increased levels of unconjugated bilirubin may reflect increased red blood cell turnover or impaired placental clearance. Whether Intralipid is less well tolerated earlier in gestation remains to be determined.
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Affiliation(s)
- Brian D. Piccolo
- USDA/ARS-Arkansas Children’s Nutrition Center, Little Rock, AR, U.S.A
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, U.S.A
| | - Athena Chen
- Department of Pathology, Oregon Health and Science University, Portland, OR, U.S.A
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, U.S.A
| | - Samantha Louey
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, U.S.A
| | - Kent L.R. Thornburg
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, U.S.A
| | - Sonnet S. Jonker
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, U.S.A
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Chattergoon N, Louey S, Jonker SS, Thornburg KL. Thyroid hormone increases fatty acid use in fetal ovine cardiac myocytes. Physiol Rep 2023; 11:e15865. [PMID: 38010207 PMCID: PMC10680578 DOI: 10.14814/phy2.15865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/24/2023] [Accepted: 10/24/2023] [Indexed: 11/29/2023] Open
Abstract
Cardiac metabolic substrate preference shifts at parturition from carbohydrates to fatty acids. We hypothesized that thyroid hormone (T3 ) and palmitic acid (PA) stimulate fetal cardiomyocyte oxidative metabolism capacity. T3 was infused into fetal sheep to a target of 1.5 nM. Dispersed cardiomyocytes were assessed for lipid uptake and droplet formation with BODIPY-labeled fatty acids. Myocardial expression levels were assessed PCR. Cardiomyocytes from naïve fetuses were exposed to T3 and PA, and oxygen consumption was measured with the Seahorse Bioanalyzer. Cardiomyocytes (130-day gestational age) exposed to elevated T3 in utero accumulated 42% more long-chain fatty acid droplets than did cells from vehicle-infused fetuses. In utero T3 increased myocardial mRNA levels of CD36, CPT1A, CPT1B, LCAD, VLCAD, HADH, IDH, PDK4, and caspase 9. In vitro exposure to T3 increased maximal oxygen consumption rate in cultured cardiomyocytes in the absence of fatty acids, and when PA was provided as an acute (30 min) supply of cellular energy. Longer-term exposure (24 and 48 h) to PA abrogated increased oxygen consumption rates stimulated by elevated levels of T3 in cultured cardiomyocytes. T3 contributes to metabolic maturation of fetal cardiomyocytes. Prolonged exposure of fetal cardiomyocytes to PA, however, may impair oxidative capacity.
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Affiliation(s)
- Natasha Chattergoon
- Center for Developmental Health, Knight Cardiovascular InstituteOregon Health & Science UniversityPortlandOregonUSA
| | - Samantha Louey
- Center for Developmental Health, Knight Cardiovascular InstituteOregon Health & Science UniversityPortlandOregonUSA
| | - Sonnet S. Jonker
- Center for Developmental Health, Knight Cardiovascular InstituteOregon Health & Science UniversityPortlandOregonUSA
| | - Kent L. Thornburg
- Center for Developmental Health, Knight Cardiovascular InstituteOregon Health & Science UniversityPortlandOregonUSA
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Wang J, Wang X, Wan W, Guo Y, Cui Y, Liu W, Guo F. Effects of Shenfu injection on myocardial adenosine receptors in rats with myocardial ischemia-reperfusion postconditioning. Hum Exp Toxicol 2021; 40:S300-S309. [PMID: 34465228 DOI: 10.1177/09603271211041668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Shenfu injection (SFI) has been reported to have a protection against myocardial ischemia-reperfusion (MI/R) injury. However, the changes of adenosine receptors in MI/R postconditioning when pretreated with SFI are unclear. METHODS Forty-five rats were randomly divided into sham group (sham), MI/R postconditioning group (MI/R-post), low-dose SFI group (1 mL/kg), middle-dose SFI group (2.5 mL/kg), and high-dose SFI group (5 mL/kg). In SFI groups, SFI was intravenously injected before reperfusion, and rats were treated with ischemic postconditioning after ischemia for 30 min. After 24 h of reperfusion, the levels of Ca2+ and cAMP in blood platelets were analyzed. Myocardial infarct volume and myocardial pathology were observed. The levels of adenosine receptor subtypes A1, A2b, and A3 in myocardium were analyzed using immunohistochemistry and Western blot. The oxidative stress-related indicators were also observed. RESULTS Compared with the MI/R-post group, SFI ameliorated the MI/R injury by decreasing the myocardial infarct area, oxidative stress, and concentration of Ca2+ and cAMP (p < 0.01). Pretreatment with SFI enhanced the expression of adenosine receptors A1 and A2b in a dose manner compared with the MI/R-post group. In contrast, the levels of adenosine receptor A3 were increased after MI/R postconditioning compared with the sham group, and its expression continued to increase with the increase of SFI. Furthermore, the oxidative stress reduced with the concentrations of SFI. CONCLUSION These results demonstrated that pretreatment with SFI might regulate the expression of adenosine receptors to improve the MI/R postconditioning.
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Affiliation(s)
- Jie Wang
- Cardiac Intensive Care Unit, 519688Yantaishan Hospital, Yantai, China
| | - Xiaohuan Wang
- Department of Cardiology, 91589Gansu Provincial Hospital, Lanzhou, China
| | - Weiping Wan
- Department of Ultrasound, 519688Yantaishan Hospital, Yantai, China
| | - Yuanying Guo
- School of Public Health, LKS Faculty of Medicine, The University of Hongkang, China
| | - Yanfang Cui
- Department of Ultrasound, 519688Yantaishan Hospital, Yantai, China
| | - Wenbo Liu
- Department of Cardiology, 519688Yantaishan Hospital, Yantai, China
| | - Fangming Guo
- Department of Cardiology, 519688Yantaishan Hospital, Yantai, China
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Wilburn AN, Giraud GD, Louey S, Morgan T, Gandhi N, Jonker SS. Systemic arterial hypertension but not IGF-I treatment stimulates cardiomyocyte enlargement in neonatal lambs. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1038-R1048. [PMID: 30480483 DOI: 10.1152/ajpregu.00198.2018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Although cardiomyocyte terminal differentiation is nearly complete at birth in sheep, as in humans, very limited postnatal expansion of myocyte number may occur. The capacity of newborn cardiomyocytes to respond to growth stimulation by proliferation is poorly understood. Our objective was to test this growth response in newborn lambs with two stimuli shown to be potent inducers of cardiomyocyte growth in fetuses and adults: increased systolic load (Load) and insulin-like growth factor I (IGF-I). Vascular catheters and an inflatable aortic occluder were implanted in lambs. Hearts were collected for analysis at 18 days of age after a 7-day experiment and compared with control hearts. Load hearts, but not IGF-I hearts, were heavier ( P = 0.001) because of increased mass of the left ventricle (LV), septum, and left atrium (40-50%, P = 0.004). Terminal differentiation and cell cycle activity were not different between groups. Myocyte length was 7% greater in Load lamb hearts ( P < 0.05), and binucleated myocytes, which comprise ~90% of LV cells, were 25% larger in volume ( P = 0.03). Myocyte number per gram of myocardium was decreased in all ventricles of Load lambs ( P = 0.01). Cells from the IGF-I group were not different by any comparison. These results suggest that the newborn sheep LV responds to systolic stress with cardiomyocyte hypertrophy, not proliferation. Furthermore, IGF-I is ineffective at stimulating cardiomyocyte proliferation at this age (despite effectiveness when administered before birth). Thus, to expand cardiomyocyte number in the newborn heart, therapies other than systolic pressure load and IGF-I treatment need to be developed.
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Affiliation(s)
- Adrienne N Wilburn
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon.,Pacific University , Forest Grove, Oregon
| | - George D Giraud
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon.,Department of Veterans Affairs Portland Health Care System , Portland, Oregon
| | - Samantha Louey
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
| | - Terry Morgan
- Department of Pathology, Oregon Health & Science University , Portland, Oregon
| | - Nainesh Gandhi
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
| | - Sonnet S Jonker
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health & Science University , Portland, Oregon
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