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The development of heart and heart-lung transplantation at Stanford. Honored guest's lecture.

Transplantation of the heart is now accepted and perhaps even routine therapy for patients near death from heart disease. Better, more specific, less toxic molecules are under investigation for the control of rejection. The Holy Grail of tolerance is not beyond the realm of possibility. The mini-chimera concept almost certainly raises the specter of potentially successful xenografts. If not in this decade, certainly in this generation. Transplantation of the heart and both lungs constituted the first successful lung transplant of any kind. The ultimate division of indications for single lung, sequential bilateral lung, or heart-lung transplantation will be settled only by the accumulation of more clinical data. With respect to pulmonary transplantation, a few technical points have become clear. First, the double lung transplant with a tracheal anastomosis has been abandoned owing to the complications of tracheal stenosis and tracheal dehiscence. Second, there is no need to wrap the bronchial anastomosis with omentum; there is no need to "telescope" the donor bronchus. Finally, simple, continuous polypropylene suture technique should be used for any tracheal (heart-lung transplantation) or bronchial anastomosis.

Academic Medical Centers↗

Metabolic therapy for patients with diabetes mellitus and coronary artery disease.

Patients with diabetes mellitus and ischemic heart disease more frequently develop heart failure and have a greater amount of myocardial ischemia, often silent, compared with patients without diabetes. Furthermore, patients with coronary artery disease (CAD) and diabetes or insulin resistance have altered myocardial metabolism and accelerated and diffuse atherogenesis with involvement of distal coronary segments that causes chronic hypoperfusion and hibernation. Therefore, in patients with diabetes and CAD, the ischemic metabolic changes are heightened by the metabolic changes in patients with diabetes. An important metabolic alteration in patients with diabetes is the increase in free fatty acid (FFA) concentrations and the increased skeletal muscle and myocardial FFA uptake and oxidation. The increased uptake and utilization of FFA and the reduced utilization of glucose as a source of energy during stress and ischemia contribute to the increased susceptibility of diabetic hearts to myocardial ischemia and to a greater decrease of myocardial performance for a given amount of ischemia compared with nondiabetic hearts. A therapeutic approach aimed at an improvement in cardiac metabolism through manipulations of the use of metabolic substrates should result in an improvement in myocardial ischemia and left ventricular (LV) function. The inhibition of FFA oxidation with trimetazidine improves cardiac metabolism at rest, increases cardiac resistance to ischemia, and therefore reduces the decrease of LV function caused by chronic hypoperfusion and repetitive episodes of myocardial ischemia in patients with and without diabetes. Thus, modulation of myocardial FFA metabolism should be the key target for metabolic interventions in patients with CAD with and without diabetes. In patients with diabetes, the effects of modulation of FFA metabolism should be even greater compared with those observed in patients without diabetes. Because of its effect on cardiac metabolism at rest and its effects on myocardial ischemia and LV function, trimetazidine should always be considered for the treatment of patients with diabetes with CAD with or without LV dysfunction.

Coronary Disease↗

V gamma 1 gammadelta T cells regulate type-1/type-2 immune responses and participate in the resistance to infection and development of heart inflammation in Trypanosoma cruzi-infected BALB/c mice.

Many different cell populations or lineages participate in the resistance to Trypanosoma cruzi infection. gammadelta T cells may also take part in a network of interactions that lead to control of T. cruzi infection with minimal tissue damage by controlling alphabeta T cell activation, as was previously suggested. However, the gammadelta T cell population is not homogeneous and its functions might vary, depending on T cell receptor usage or distinct stimulatory conditions. In this study, we show that the in vivo depletion of V gamma 1-bearing gammadelta T cells, prior to the infection of BALB/c mice with the Y strain of T. cruzi, induces an increased susceptibility to the infection with lower amounts of IFN-gamma being produced by conventional CD4+ or CD8+ T cells. In addition, the production of IL-4 by spleen T cells in V gamma 1-depleted mice was increased and the production of IL-10 remained unchanged. Since V gamma 1(+) gammadelta T cell depletion diminished the conversion of naive to memory/activated CD4 T cells and the production of IFN-gamma during the acute infection, these cells appear to function as helper cells for conventional CD4+ Th1 cells. Depletion of V gamma 1(+) cells also reduced the infection-induced inflammatory infiltrate in the heart and skeletal muscle. More importantly, V gamma 1(+) cells were required for up-regulation of CD40L in CD4+ and CD8+ T cells during infection. These results show that a subset of gammadelta T cells (V gamma 1(+)), which is an important component of the innate immune response, up-regulates the type 1 arm of the adaptative immune response, during T. cruzi infection.

Animals↗

Stages of normal development in the medaka Oryzias latipes.

Unfertilized eggs of Oryzias latipes were artificially inseminated and incubated at 26+/-1 degrees C. Careful observation of the process of embryonic development by light microscopy allowed division of the process into 39 stages based on diagnostic features of the developing embryos. The principal diagnostic features are the number and size of blastomeres, form of the blastoderm, extent of epiboly, development of the central nervous system, number and form of somites, optic and otic development, development of the notochord, heart development, blood circulation, the size and movement of the body, development of the tail, membranous fin (fin fold) development, and development of such viscera as the liver, gallbladder, gut tube, spleen and swim (air) bladder. After hatching, development of the larvae (fry) and young can be divided into six stages based on such diagnostic features as the fins, scales and secondary sexual characteristics.

Animals↗

Greater propensity of diabetic myocardium for oxidative stress after myocardial infarction is associated with the development of heart failure.

Diabetic patients manifest an increased incidence of heart failure (HF) after myocardial infarction (MI), which presages an increase in morbidity and mortality. Although oxidative stress has been implicated in diabetic complications, oxidative stress status associated with comorbid conditions that frequently accompany diabetes remains unknown. Therefore, we examined antioxidants and oxidative stress in the surviving myocardium in relation to ventricular function during diabetic HF following MI. MI was produced in diabetic and nondiabetic rats by ligation of the left coronary artery. At 4 weeks post-MI, LV systolic pressure (LVSP), rate of pressure rise (+dP/dt), and rate of pressure decay (-dP/dt) were depressed to a significantly greater extent in diabetic compared to nondiabetic MI animals. Higher levels of myocardial 8-isoprostane (8-iso PGF(2alpha)), oxidized glutathione (GSSG), as well as greater upregulation of superoxide dismutase (SOD) and catalase (CAT) protein expression paralleled by increases in enzymatic activity was observed in the diabetic MI animals, indicating higher oxidative stress. These data demonstrate a greater derangement of oxidative stress in the surviving tissues of diabetic post-MI rat hearts concomitant with an increased functional severity of HF, and suggest that chronic antioxidant therapy may be useful for the prophylaxis of subsequent HF after MI associated with diabetes.

Animals↗

Collagen content in normal, pressure, and pressure-volume overloaded developing human hearts.

Increased myocardial collagen accompanies pressure overload of the adult left ventricle. This phenomenon is poorly understood in infants. This study compares the myocardial volume fraction of collagen in infants who did not have primary heart disease with infants with isolated pressure overload of the right ventricle (tetralogy of Fallot [ToF]), and with infants with combined volume and pressure overload (aortic valve atresia [AVA]). The distribution of collagen in the neonatal myocardium was also determined. We measured the volume fraction of collagen from right ventricular biopsy specimens of cadaver hearts in normal infants (1 to 9 months old; n = 7), infants with ToF (1 day to 9 months old; n = 9), newborns with AVA (AVA-NB) (1 to 4 days old; n = 5), and older patients with AVA (AVA-I) (5 to 8 months old; n = 5). Myocardium from 3 patients undergoing repair of ToF (6 to 8 months old) was also analyzed. Specimens were stained with Masson's trichrome and myocardial volume fraction of collagen determined by point counting. Myocardial volume fraction of collagen was significantly higher (p = 0.02) in AVA-I patients (8.0 +/- 3.5%) versus normal (3.3 +/- 2.7%), ToF (3.2 +/- 1.8%), and AVA-NB (3.5 +/- 2.3%) patients. There was a tendency for increased collagen in the subendocardium, especially in AVA-I patients (p > 0.05). We conclude that patients with AVA-I have increased collagen relative to normal subjects, patients with ToF, and patients with AVA-NB, and that this increase is greatest in the subendocardium.

Aortic Valve↗

Cytosolic glucocorticoid receptors in the developing rat heart.

Glucocorticoid hormones alter functional cardiac responses in the rat heart. In the neonatal rat heart, glucocorticoid treatment on post-natal day 2 alters heart function for up to 3 weeks post-injection, which suggests that cardiac glucocorticoid receptors mediate cardiac function in neonates. However, glucocorticoid receptors have not been identified in neonatal rat heart. Glucocorticoid receptor binding was measured in neonatal rat heart cytosol extract using [3H] dexamethasone as ligand, and characterized by competition assays and Scatchard analysis. Saturable, specific, high affinity glucocorticoid receptor binding was found in the cytosol of the neonatal rat heart. We then examined the effects of a single, post-natal day 2 injection of hydrocortisone acetate on glucocorticoid receptor binding in 12 to 14-day-old rat heart. While this injection paradigm results in altered cardiac function in 12-day-old rat hearts, cytosol glucocorticoid receptor binding in 12 to 14-day-old heart was not altered by treatment on post-natal day 2 with hydrocortisone acetate. It is postulated that exposure to elevated glucocorticoid levels on neonatal day 2 may alter cardiac function by producing permanent organizational effects on cardiac tissue.

Animals↗

A calcineurin-dependent transcriptional pathway for cardiac hypertrophy.

In response to numerous pathologic stimuli, the myocardium undergoes a hypertrophic response characterized by increased myocardial cell size and activation of fetal cardiac genes. We show that cardiac hypertrophy is induced by the calcium-dependent phosphatase calcineurin, which dephosphorylates the transcription factor NF-AT3, enabling it to translocate to the nucleus. NF-AT3 interacts with the cardiac zinc finger transcription factor GATA4, resulting in synergistic activation of cardiac transcription. Transgenic mice that express activated forms of calcineurin or NF-AT3 in the heart develop cardiac hypertrophy and heart failure that mimic human heart disease. Pharmacologic inhibition of calcineurin activity blocks hypertrophy in vivo and in vitro. These results define a novel hypertrophic signaling pathway and suggest pharmacologic approaches to prevent cardiac hypertrophy and heart failure.

Angiotensin II↗

New developments in heart failure: role of endothelin and the use of endothelin receptor antagonists.

Despite conventional therapy, there is still much room for improvement in the prognosis of patients with chronic systolic heart failure. Evidence supports a role for endothelin-1 (ET-1), a potent vasoconstrictor, in the pathophysiology of heart failure. Given its potentially deleterious effects, the optimal treatment of heart failure may need to include efforts directed toward antagonizing this hormone. In support of this notion, the use of ET receptor antagonists produces a number of beneficial effects in heart failure, including both improvements in hemodynamics and reductions in the levels of other vasoconstricting neurohormones. There are at least 2 receptors for ET-1 (the ET-A and ET-B receptor), and the effects of ET-1 binding differ depending on the receptor involved. It is still unclear whether blockade of the ET-A receptor alone or the combined blockade of both the ET-A and ET-B receptors will be most efficacious as a therapeutic strategy. Long-term benefits have been achieved with the use of a mixed ET-A/B receptor antagonist, when added to standard triple-drug therapy, in patients with severe heart failure. We await the results of ongoing trials to determine if these agents will fulfill the promise of adding substantial incremental benefit to the treatment of the disease.

Bosentan↗

Deletion of the cancer-amplified coactivator AIB3 results in defective placentation and embryonic lethality.

The amplified in breast cancer-3 (AIB3, ASC-2, RAP250, PRIP, TRBP, NRC, or NcoA6) gene is characterized as a cancer-amplified transcriptional coactivator for nuclear receptors, which include the peroxisome proliferator-activated receptor gamma (PPARgamma). To assess its biological function, we deleted the AIB3 gene in mice by homologous recombination. AIB3(+/-) mice are developmentally normal and fertile. AIB3(-/-) embryos exhibit growth restriction and lethality during 9.75-11.5 days postconception. The embryonic lethality is probably attributed to defects in the development of the placental vascular network and cardiac hypoplasia. These defects include the failure of labyrinthine development, the dilation of maternal blood sinuses, the massive erythrophagocytosis by trophoblasts, the alteration of trophoblast populations, and the lower proliferation of myocardium, which are similar to those encountered in mice lacking PPARgamma or the PPARgamma-binding protein (PBP, TRAP220, or DRIP205). In addition, the transcriptional activities of PPARgamma are significantly affected in mouse embryonic fibroblasts lacking AIB3. These results suggest that AIB3 is required for PPARgamma function in placental development and for normal heart development. These results also indicate that the biological function of AIB3 is not redundant with other classes of nuclear receptor coactivators such as PBP and members of the steroid receptor coactivator family.

Animals↗

The infant growth of boys who later develop coronary heart disease.

BACKGROUND: The association between low birth-weight and coronary heart disease has been repeatedly shown. Only two previous studies have examined the effects of weight gain during infancy and later coronary heart disease. AIM: The aim of this study was to assess the association between infant growth and coronary heart disease in adult life. METHODS: 2345 men born at the Helsinki City Maternity Hospital during 1934-44 with information on birth size and growth during infancy and childhood were included in the study cohort. RESULTS: There was a 3-fold fall in hazard ratios for coronary heart disease between men who weighed < or = 8 kg at 1 year and those who weighed > 12 kg (P < 0.00001). The fall was steeper among men whose placental weight at birth was below average. Men born into families with low socio-economic status had lower weight gain during infancy and higher rates of coronary heart disease. The increased risk of coronary heart disease in men who grew slowly during infancy was greatest in those who had low placental weight at birth. CONCLUSIONS: Poor infant growth and small body size at one year predict coronary heart disease more strongly than low birth-weight.

Adult↗