Anderson H. Kuo

Cardiac remodelling in a baboon model of intrauterine growth restriction mimics accelerated ageing

Rodent models of intrauterine growth restriction (IUGR) successfully identify mechanisms that can lead to short‐term and long‐term detrimental cardiomyopathies but differences between rodent and human cardiac physiology and placental‐fetal development indicate a need for models in precocial species for translation to human development. We developed a baboon model for IUGR studies using a moderate 30% global calorie restriction of pregnant mothers and used cardiac magnetic resonance imaging to evaluate offspring heart function in early adulthood. Impaired diastolic and systolic cardiac function was observed in IUGR offspring with differences between male and female subjects, compared to their respective controls. Aspects of cardiac impairment found in the IUGR offspring were similar to those found in normal controls in a geriatric cohort. Understanding early cardiac biomarkers of IUGR using non‐invasive imaging in this susceptible population, especially taking into account sexual dimorphisms, will aid recognition of the clinical presentation, development of biomarkers suitable for use in humans and management of treatment strategies.

Maternal nutrient restriction during pregnancy and lactation leads to impaired right ventricular function in young adult baboons

Maternal nutrient restriction induces intrauterine growth restriction (IUGR) and leads to heightened cardiovascular risks later in life. We report right ventricular (RV) filling and ejection abnormalities in IUGR young adult baboons using cardiac magnetic resonance imaging. Both functional and morphological indicators of poor RV function were seen, many of which were similar to effects of ageing, but also with a few key differences. We observed more pronounced RV changes compared to our previous report of the left ventricle, suggesting there is likely to be a component of isolated RV abnormality in addition to expected haemodynamic sequelae from left ventricular dysfunction. In particular, our findings raise the suspicion of pulmonary hypertension after IUGR. This study establishes that IUGR also leads to impairment of the right ventricle in addition to the left ventricle classically studied.

Premature Brain Aging in Baboons Resulting from Moderate Fetal Undernutrition

Contrary to the known benefits from a moderate dietary reduction during adulthood on life span and health, maternal nutrient reduction during pregnancy is supposed to affect the developing brain, probably resulting in impaired brain structure and function throughout life. Decreased fetal nutrition delivery is widespread in both developing and developed countries, caused by poverty and natural disasters, but also due to maternal dieting, teenage pregnancy, pregnancy in women over 35 years of age, placental insufficiency, or multiples. Compromised development of fetal cerebral structures was already shown in our baboon model of moderate maternal nutrient reduction. The present study was designed to follow-up and evaluate the effects of moderate maternal nutrient reduction on individual brain aging in the baboon during young adulthood (4–7 years; human equivalent 14–24 years), applying a novel, non-invasive neuroimaging aging biomarker. The study reveals premature brain aging of +2.7 years (p < 0.01) in the female baboon exposed to fetal undernutrition. The effects of moderate maternal nutrient reduction on individual brain aging occurred in the absence of fetal growth restriction or marked maternal weight reduction at birth, which stresses the significance of early nutritional conditions in life-long developmental programming. This non-invasive MRI biomarker allows further longitudinal in vivo tracking of individual brain aging trajectories to assess the life-long effects of developmental and environmental influences in programming paradigms, aiding preventive and curative treatments on cerebral atrophy in experimental animal models and humans.

Prenatal steroid administration leads to adult pericardial and hepatic steatosis in male baboons

Developmental programming studies indicate that glucocorticoids modify fetal development. We hypothesized that administration of the synthetic glucocorticoid (sGC) betamethasone to pregnant baboons at doses and stages of fetal life equivalent to human obstetric practice to decrease premature offspring morbidity and mortality, programs lipid metabolism. In 10-year-old male baboons (human equivalent 40) exposed in fetal life to betamethasone or saline, we quantified pericardial fat and hepatic lipid content with magnetic resonance imaging and spectroscopy. sGC offspring delivered at term as do most sGC-exposed human neonates. Pericardial fat thickness (7.7±3.6 mm vs 3.1±1.1 mm, M±s.d.; P=0.022; n=5) and hepatic fatty acids (13.3±11.0% vs 2.5±2.2%; P=0.046; n=5) increased following sGC without birth weight or current body morphometric differences. Our results indicate that antenatal sGC therapy caused abnormal fat deposition and adult body composition in mid-life primate offspring. The concern raised is that this degree of pericardial and hepatic lipid accumulation can lead to harmful local lipotoxicity. In summary, developmental programing by sGC produces a mid-life metabolically obese but normal weight phenotype. Prior studies show sexually dimorphic responses to some programming challenges thus female studies are necessary.

Sex-dimorphic acceleration of pericardial, subcutaneous, and plasma lipid increase in offspring of poorly nourished baboons

Developmental programming by reduced maternal nutrition alters function in multiple offspring physiological systems, including lipid metabolism. We have shown that intrauterine growth restriction (IUGR) leads to offspring cardiovascular dysfunction with an accelerated aging phenotype in our nonhuman primate, baboon model. We hypothesized age-advanced pericardial fat and blood lipid changes. In pregnancy and lactation, pregnant baboons ate ad lib (control) or 70% ad lib diet (IUGR). We studied baboon offspring pericardial lipid deposition with magnetic resonance imaging at 5–6 years (human equivalent 20–24 years), skinfold thickness, and serum lipid profile at 8–9 years (human equivalent 32–36 years), comparing values with a normative life-course baboon cohort, 4–23 years. Increased pericardial fat deposition occurred in IUGR males but not females. Female but not male total cholesterol, low-density lipoprotein, and subcutaneous fat were increased with a trend of triglycerides increase. When comparing IUGR changes to values in normal older baboons, the increase in male apical pericardial fat was equivalent to advancing age by 6 years and the increase in female low-density lipoprotein to an increase of 3 years. We conclude that reduced maternal diet accelerates offspring lipid changes in a sex-dimorphic manner. The interaction between programming and accelerated lipogenesis warrants further investigation.

Coronary-Pulmonary Artery Fistulas: A Systematic Review

Purpose: Coronary-pulmonary arterial fistulas (CPAFs) are rare coronary artery anomalies that have been described only in limited case reports. This study aims to evaluate the clinical presentation and imaging findings of CPAFs collected from 6 participating medical centers along with CPAFs reported in the literature, to discern any general trends present in CPAFs. Materials and Methods: A total of 25 cases of CPAF diagnosed by coronary computed tomography angiography were collected across 6 participating institutions. In addition, utilizing a PubMed literature search, 78 additional CPAF cases were obtained. The imaging findings and relevant clinical history were reviewed. Results: Of the 103 CPAF patients, 60 (63% of patients with sex known) were male, with ages ranging from newborn to 88 years (mean=46.1 y). The most common symptoms reported were chest pain (n=40, 39%) and dyspnea (n=26, 25%), with a murmur as the most common physical examination finding (n=38, 37%). The most common coronary artery of origin for a CPAF was the left main/left anterior descending (n=87, 84%), followed by the right coronary artery (n=39, 38%). The fistula most commonly terminated in the main pulmonary artery (n=92, 89%). Multiple CPAFs were present in 46 cases (45%). Coronary artery aneurysms were identified in 20 cases (19%). Pediatric CPAF cases were usually associated with pulmonary atresia with ventricular septal defect. Conclusions: CPAFs are seen in a variety of clinical settings, from infants with advanced congenital heart disease to elderly patients who have undergone revascularization surgery. Although coronary artery fistulas have previously been described as rarely involving multiple coronary arteries, with the right coronary artery being most often involved, our series demonstrates that multiple fistulas are commonly present, with the most common pattern being between the left main/left anterior descending and the main pulmonary trunk.

Intrauterine growth restriction results in persistent vascular mismatch in adulthood.

Intrauterine growth restriction (IUGR) increases offspring risk of chronic diseases later in life, including cardiovascular dysfunction. Our prior studies suggest biventricular cardiac dysfunction and vascular impairment in baboons who were IUGR at birth because of moderate maternal nutrient reduction. The current study reveals changes in artery sizes, distensibility, and blood flow pattern in young adult IUGR baboons, which may contribute to cardiac stress. The pattern of abnormality observed suggests that vascular redistribution seen with IUGR in fetal life may continue into adulthood.

Ageing changes in biventricular cardiac function in male and female baboons (Papio spp.)

Life course changes in cardiovascular function in a non‐human primate have been comprehensively characterized. Age‐related declines in normalized left ventricular stroke volume and cardiac output were found with corresponding decreases in biventricular ejection fractions and filling rates. There were age‐related decreases in male and female baboon normalized left ventricular myocardial mass index, which declined at similar rates. Systolic functional declines in right ventricular function were observed with age, similar to the left ventricle. Sex differences were found in the rates and directions of right ventricular volume changes along with decreased end‐systolic right ventricular sphericity. The results validate the baboon as an appropriate model for translational studies of cardiovascular functional decline with ageing.

MRI based biomarker for brain aging in rodents and non-human primates

This work presents two novel species-specific adaptations of a MRI based biomarker that indicates individual deviations from normal brain aging trajectories for rodents and non-human primates. By employing automatic, species-specific preprocessing of anatomical brain MRI as well as high-dimensional pattern recognition methods, this approach uses the distribution of healthy brain-aging patterns to estimate individual brain ages. This biomarker may probably enable tracking the effects of developmental and environmental influences, manipulations, and (preventive) treatments on individual deviations from species-specific brain aging trajectories in experimental mammal models across the life-course.

Antenatal Synthetic Glucocorticoid Exposure at Human Therapeutic Equivalent Doses Predisposes Middle-Age Male Offspring Baboons to an Obese Phenotype That Emerges With Aging

Introduction: Women threatening premature delivery receive synthetic glucocorticoids (sGC) to accelerate fetal lung maturation, reducing neonatal mortality and morbidity. Few investigations have explored potential long-term offspring side effects. We previously reported increased pericardial fat and liver lipids in 10-year-old (human equivalent 40 years) male baboons exposed to 3 antenatal sGC courses. We hypothesized middle-aged sGC male offspring show obesity-related morphometric changes. Methods: Pregnant baboons received courses of 2 betamethasone injections (175 μg·kg−1·d−1 intramuscular) at 0.6, 0.64, and 0.68 gestation. At 10 to 12.5 years, we measured morphometrics and serum lipids in 5 sGC-exposed males and 10 age-matched controls. We determined whether morphometric parameters predicted amount of pericardial fat or lipids. Life-course serum lipids were measured in 25 males (7-23 years) providing normal regression formulas to compare sGC baboons’ lipid biological and chronological age. Results: Birth weights were similar. When studied, sGC-exposed males showed a steeper weight increase from 8 to 12 years and had increased waist and hip circumferences, neck and triceps skinfolds, and total and low-density lipoprotein cholesterol. Triceps skinfold correlated with apical and midventricular pericardial fat thickness, hip and waist circumferences with insulin. Conclusions: Triceps skinfold and waist and hip circumferences are useful biomarkers for identifying individuals at risk for obesity and metabolic dysregulation following fetal sGC exposure. Prenatal sGC exposure predisposes male offspring to internal adiposity, greater body size, and increased serum lipids. Results provide further evidence for developmental programming by fetal sGC exposure and call attention to potential emergence of adverse life-course effects.