Disproportionate reduction of actin synthesis in hearts of starved rats

Complete recovery from severe myocardial dysfunction in a patient with anorexia nervosa

This report describes a patient who experienced cardiopulmonary arrest caused by severe hypoglycemia and malnutrition, which was successfully treated with percutaneous cardiopulmonary support (PCPS) and intra-aortic balloon pumping (IABP). A 33-year-old female with anorexia nervosa (AN) was transferred to the emergency center because of a loss of consciousness. On admission, she was extremely emaciated, hypotensive, and hypoglycemic (10 mg/dl). A chest X-ray showed butterfly shadow. Echocardiography showed severe hypokinesis of left ventricular wall motion. On the 3rd hospital day, she experienced cardiac arrest. Myocardial dysfunction caused by malnutrition was suspected, and therefore both PCPS and IABP were administered for circulatory support and myocardial protection. Thereafter, cardiac function gradually recovered and she was later weaned from PCPS and IABP on the 9th and the 10th hospital day, respectively. She was discharged from the intensive care unit on the 43rd hospital day with normal cardiac function. Her neurological outcome after 6 months as evaluated by the Glasgow Outcome Scale was considered to be good recovery. Cardiomyopathy in AN patients is reversible ventricular dysfunction, and circulation assisting devices are considered for the treatment of cardiogenic shock.

Neonatal cardiomyocyte ploidy reveals critical windows of heart development

BACKGROUND

The aim of our study was to find out, whether cardiomyocyte genome duplication participates in developmental programming of adult hypertension and impaired heart aerobic capacity, and if it does, whether ploidy-related programming is reversible and what are the timeframes of the most critical window. For this propose we studied the effect of the well-known factors of programming, including growth retardation, infection, and cardiac overload on the level of neonatal cardiomyocyte ploidy, protein content and shape.

METHODS

Using the model of rat cryptosporidial gastroenteritis, we shifted the time point of infection day by day through the neonatal period and traced the immediate and postponed effects of disease on isolated cardiomyocyte ploidy, phenotype, and protein content.

RESULTS

We found that gastroenteritis caused cardiac atrophy and a burst-like premature genome accumulation, elongation, narrowing and protein loss in the cardiomyocytes. These changes resulted in sharp increase of DNA content at the expense of contractile proteins. We also revealed clear indications of critical window of heart development during the peak of cardiomyocyte transition from proliferation to hypertrophy. After the rehabilitation, the atrophy of heart and cardiomyocyte remodelling showed a conspicuous restoration, whereas the hyperpolyploidization did not regress. An irreversible manner of excessive genome duplication and its well-known ability to alter gene expression confirm our suggestion that it is implicated in the ontogenetic programming of heart development.

CONCLUSION

We provided the first evidence that developmental programming can operate through cardiomyocyte genome duplication and that the critical window coincides with cell transition from proliferation to hypertrophy. Our data help determine the timing of critical window for human heart and would allow successful prevention of human cardiac abnormalities even before they become tangible.

Cardiac findings in adolescents with anorexia nervosa at diagnosis and after weight restoration

The aim of this study was to compare heart abnormalities in a group of young women with anorexia nervosa at diagnosis and after weight restoration. A total of 40 young women with anorexia nervosa were evaluated, at baseline, (diagnosis) and follow-up (9 to 18 months later) and matched with 40 healthy women of the same age and of normal weight. QT interval was measured from surface electrocardiograms. QT dispersion was defined as the difference between maximum QT and minimum QT occurring in any of the 12 leads. Left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left ventricular mass, left ventricular mass index, cardiac output, fractional shortening and fractional ejection, were measured by echocardiography. In anorexia nervosa patients, corrected QT interval and QT dispersion, significantly decreased from baseline to follow-up. Left ventricular end-diastolic dimension, left ventricular mass index, and cardiac output, in anorexia nervosa were significantly lower at diagnosis than at follow-up after weight restoration.

CONCLUSION

Adolescents with anorexia nervosa have significant functional and structural cardiac abnormalities; weight gain was associated with improvement. Appropriate attention should be paid to cardiac involvement.

[Cardiac disorders in young women with anorexia nervosa]

INTRODUCTION AND OBJECTIVES

The objective of this study was to compare heart abnormalities in young women with anorexia nervosa and in a control group of the same age and sex. Patients and method. We report a matched case-control study of 30 adolescents with anorexia nervosa and 30 healthy women of the same age with normal weight. An electrocardiogram and echocardiogram were done. Heart parameters were measured on the electrocardiographic tracings, and QT dispersion was defined as the difference between maximum QT and minimum QT in any of the 12 leads. Diameter, mass and left ventricular mass index were measured.

RESULTS

QT and corrected QT intervals were significantly greater in patients with anorexia nervosa than in the control group. QT dispersion and corrected QT dispersion were significantly greater in anorexia nervosa than in the control group (QTd, 59.3 23.0 vs 38.4 8.0 ms; p = 0.000; QTcd, 56.5 24.2 vs. 40.3 21.8 ms; p = 0.011). Left ventricular mass was significantly lower in young women with anorexia nervosa. We found a significant relationship between body mass index and left ventricular mass index, and between the former and corrected QT dispersion.

CONCLUSIONS

Adolescents with anorexia nervosa show significant cardiac disorders in comparison to healthy women of the same age. This finding may be a useful indicator of the risk of arrhythmia and sudden death in patients with anorexia nervosa.

Cardiac gene expression profile and lipid accumulation in response to starvation

Starvation induces many biochemical and histological changes in the heart; however, the molecular events underlying these changes have not been fully elucidated. To explore the molecular response of the heart to starvation, microarray analysis was performed together with biochemical and histological investigations. Serum free fatty acids increased twofold in both 16- and 48-h-fasted mice, and cardiac triglyceride content increased threefold and sixfold in 16- and 48-h-fasted mice, respectively. Electron microscopy showed numerous lipid droplets in hearts of 48-h-fasted mice, whereas fewer numbers of droplets were seen in hearts from 16-h-fasted mice. Expression of 11,000 cardiac genes was screened by microarrays. More than 50 and 150 known genes were detected by differential expression analysis after 16- and 48-h-fasts, respectively. Genes for fatty acid oxidation and gluconeogenesis were increased, and genes for glycolysis were decreased. Many other genes for metabolism, signaling/cell cycle, cytoskeleton, and tissue antigens were affected by fasting. These data provide a broad perspective of the molecular events occurring physiologically in the heart in response to starvation.

Morphometric changes in microvasculature in rat myocardium during malnutrition

BACKGROUND

Because the interrelationship between the parenchymal cell population and the microvasculature is critical in normal organ function, the effects of starvation on rat myocardium were studied morphometrically with respect to the microvasculature.

METHODS

Morphometric analytical studies were performed on myocardium of adult, female Wistar rats (groups of 5-7 rats) on fasting days 0, 1, 2, 4, 6, 8 and 10. Since cardiac muscle is a tissue with a high level of anisotropy, methods based on the concept of vertical planes were used to describe quantitative alterations in the rat myocardium both at the cellular and ultrastructural level.

RESULTS

Morphometric analysis of electromicrographs of myocardium showed an increase in capillary density together with a decrease in capillary lumen cross-sectional area during starvation (p < .05). There was no significant change in volume fraction of the capillaries but surface density of the myocytes increased significantly (p < .01) and the diffusion distance for oxygen from the capillary lumen to the mitochondrion decreased (p < .01).

CONCLUSIONS

Malnutrition alters the interrelationship between parenchyma and vascularization in the heart. This leads to a significant decrease of the diffusion distance for metabolites. This decrease of diffusion distance may improve cellular energy supply and offers a relative protection of the metabolism in the malnourished myocyte.

Protein metabolism during nutrient deprivation and refeeding of neonatal heart cells

Pathological conditions or nutrient deprivation in the heart cause an imbalance between rates of protein synthesis and degradation, often resulting in a severe depletion of cardiac protein. We used cultured neonatal rat heart cells, a model system exhibiting positive nitrogen balance, to examine the effects of 10 h of starvation on myocardial glucose and protein metabolism. Cellular capacity for glucose utilization was depressed after starvation, as evidenced by lower hexokinase and other glycolytic enzyme activities and a 21% decrease in glucose usage. A 21.0% decrease in protein synthetic rate and an increase in protein degradation rate combined to yield a 29.5% decrease in total cellular protein during starvation. Degradation rates increased 29.0, 46.7, and 59.6% in 2-, 24-, and 96-h prelabeled cells, respectively, indicating that lability increased with half-life of proteins. During refeeding of starved, cultured cells, at least three proteins were synthesized at a lower rate. At the same time, proteins with approximate molecular masses of 45, 84, 92, and 174 kDa exhibited increased synthesis.

Starvation leads to decreased levels of mRNA for myofibrillar proteins

Malnutrition is a common complicating factor in surgical illness. To investigate the cellular changes and mechanisms responsible for the protein wasting associated with nutritional deprivation, Sprague-Dawley rats were subjected to total protein-calorie starvation for 3 (n = 12) or 5 days (n = 12) and compared to freely fed animals monitored for 3 (n = 8) or 5 (n = 8) days. Gastrocnemius protein and RNA content and levels of mRNA coding for the myofibrillar proteins myosin heavy chain, myosin light chain, and alpha-actin were measured. Starvation resulted in a significant decrease in gastrocnemius mass and protein content, and was associated with decreases in mRNA levels for the three myofibrillar proteins assayed. We conclude that changes in mRNA levels for these proteins likely contribute to the loss of peripheral protein which occurs during total nutritional deprivation. In addition, the changes in mRNA levels for these three structural proteins appear to be coordinate, suggesting that transcription of no single myofibrillar protein is rate-limiting in the regulation of skeletal muscle protein content.

Cardiac peroxisomal enzymes and starvation

In mice subjected to 3-day periods of food deprivation an increase in plasma free fatty acids occurred together with a rise in the cardiac content of fatty acyl CoA-oxidase (+ 15.2%) and catalase (+ 136.2%) activities. Stimulation of hydrogen peroxide production by the heart was found after 30 hours of fasting and this phenomenon was almost completely eliminated by 6 hours of refeeding. These data suggest that high myocardial loads of free fatty acids involve the peroxisomal enzymes in the beta-oxidation process. The resulting increase in hydrogen peroxide production could be partly responsible for the myocardial injury caused by starvation.