Oliguria without serum creatinine increase after living donor liver transplantation is associated with adverse post-operative outcomes.

BACKGROUND: Acute kidney injury (AKI) is a common complication after liver transplantation and is associated with significant morbidity and mortality. Although clinical guidelines recommend defining AKI based on serum creatinine increase and oliguria, the validity and utility of the oliguric component of AKI definition remains largely unexplored. This study examined the incidence and the impact on clinical outcomes of oliguria meeting the urine output criterion of AKI in patients undergoing liver transplantation. The authors hypothesised that oliguria was an independent risk factor for adverse post-operative outcomes. METHODS: This study retrospectively examined 320 patients who underwent living donor liver transplantation at our centre. AKI stages were allocated according to recent guidelines based on serum creatinine or urine output within 7 days of surgery. RESULTS: The incidence of oliguria meeting the urine output criterion of AKI was 50.3%. Compared with creatinine criterion alone, incorporating oliguria into the diagnostic criteria dramatically increased the measured incidence of AKI from 39.7% to 62.2%. Compared with patients diagnosed without AKI using either criterion, oliguric patients without serum creatinine increase had significantly longer intensive care unit stays (median: 5 vs. 4 days, P = 0.016), longer hospital stays (median: 60 vs. 49 days, P = 0.014) and lower chronic kidney disease-free survival rate on post-operative day 90 (54.2% vs. 73.3%, P = 0.008). CONCLUSION: Oliguria is common after liver transplantation, and incorporating oliguria into the diagnostic criteria dramatically increases the measured incidence of AKI. Oliguria without serum creatinine increase was significantly associated with adverse post-operative outcomes.

Cardiac-specific overexpression of RhoA results in sinus and atrioventricular nodal dysfunction and contractile failure.

RhoA is a low-molecular-weight GTPase that has been implicated in the regulation of hypertrophic cardiac muscle cell growth. To study the role of RhoA in control of cardiac function in vivo, transgenic mice expressing wild-type and constitutively activated forms of RhoA under the control of the cardiac-specific alpha-myosin heavy chain promoter were generated. Transgene-positive mice expressing high levels of either wild-type or activated RhoA showed pronounced atrial enlargement and manifested a lethal phenotype, often preceded by generalized edema, with most animals dying over the course of a few weeks. Echocardiographic analysis of visibly healthy wild-type RhoA transgenic mice revealed no significant change in left ventricular function. As their condition deteriorated, significant dilation of the left ventricular chamber and associated decreases in left ventricular contractility were detected. Heart rate was grossly depressed in both wild-type and activated RhoA-expressing mice, even prior to the onset of ventricular failure. Electrocardiography showed evidence of atrial fibrillation and atrioventricular block. Interestingly, muscarinic receptor blockade with atropine did not elicit a positive chronotropic response in the transgenic mice. We suggest that RhoA regulates cardiac sinus and atrioventricular nodal function and that its overexpression results in bradycardia and development of ventricular failure.

High-efficiency, long-term cardiac expression of foreign genes in living mouse embryos and neonates.

BACKGROUND: The development of improved strategies for efficient and reproducible in vivo gene transfer into the murine heart will ultimately allow the intersection of somatic and germline gene transfer strategies to study complex features of cardiac biology and diseases. METHODS AND RESULTS: For embryonic gene transfer, an adenovirus vector expressing beta-galactosidase was injected in utero into the ventricular cavity of living embryos via microsurgical approaches. The injected embryos were developed to term, and efficient expression of the transgene was detected in all cell types in the heart. For postnatal cardiac gene transfer, adenovirus was injected into the cardiac ventricle of neonatal mice, resulting in efficient expression of the transgene in the outer layer of the myocardium as well as cardiomyocytes in the middle and inner layers of the cardiac wall. Mice examined after 3 weeks displayed a pattern of expression that completely mimicked the pattern seen after 3 days, and gene expression was also found after 6 months. The infected myocytes can be identified by coinfection of an adenovirus expressing green fluorescent protein without affecting their normal physiological function. CONCLUSIONS: We have developed a new strategy to achieve efficient and long-term foreign gene expression in both embryonic and postnatal mouse myocardium via direct intracardiac injection of recombinant adenovirus. The strategy should allow the functional assessment of the expression of dominantly acting exogenous genes, overexpression of wild-type genes, and Cre recombinase-mediated gene ablations at the single-cell level in the context of the intact adult mouse myocardium.

Hemolysis of rabbit erythrocytes induced by cigarette smoke.

Cigarette smoke has been found to induce the hemolysis of rabbit erythrocytes. The particulate phase had more profound effect than the gas phase. Neither free radical scavengers such as ascorbic acid, uric acid and water-soluble vitamin E analogue nor antioxidant enzymes such as catalase and superoxide dismutase suppressed the cigarette smoke-induced hemolysis, suggesting that free radicals, hydrogen peroxide, and superoxide were not the active species.

[Genetic complementation studies using genetically engineered mice have revealed the impact of phospholamban on progression of cardiomyopathy].

It has been suggested that dilated cardiomyopathy and end-stage heart failure result in multiple defects in Ca(2+) cycling. By genetic ablation of a muscle specific sarcoplasmic reticulum Ca(2+) ATPase (SERCA2a) inhibitor, phospholamban, the broad phenotypes of murine model of dilated cardiomyopathy could be almost completely rescued. Thus, phospholamban inactivation or disruption of interaction between phospholamban and SERCA2a may provide a novel therapeutic approach for preventing the progression of heart failure.

[A comparison of sudden near maximal exercise test (dash method) and Bruce protocol for pediatric patients].

We examined 24 pediatric patients to evaluate the usefulness of sudden near maximal exercise test (dash method), where the subjects began to run at Bruce protocol of the last stage. 1) No considerable differences between two protocols were found in maximal oxygen consumption (V O2max), maximal heart rate (HRmax), maximal systolic blood pressure, and findings of electrocardiography. 2) The sudden maximal exercise test could be completed during a shorter period compared to Bruce protocol. 3) The sudden maximal exercise protocol reached 84% of HRmax and 47% of V O2max at one minute after the onset of the protocol, and produced 96% of HRmax and 89% of V O2max at two minutes after the onset. We considered that sudden maximal exercise protocol was useful to obtain a response similar to Bruce protocol at maximal exercise within a short period. We have to pay attention to the safety of the patients because their cardiopulmonary response to sudden maximal exercise protocol is dramatic.

Transient neonatal diabetes mellitus in an extremely preterm infant.

The present report concerns transient neonatal diabetes mellitus in an extremely preterm infant (gestational age 27 weeks, birth weight 718 g). The patient had intrauterine growth retardation and developed hyperglycaemia on the first day of life. Insulin administration was discontinued on the 89th day of life, which was 1 day before the original due date. This case suggests that (a) insufficient insulin secretion started at least from the second trimester of the pregnancy, and (b) the duration needed for recovery of insulin secretion was not dependent on the maturity.

Transient neonatal diabetes mellitus in extremely preterm infant.

A report of transient neonatal diabetes mellitus in an extremely preterm infant (gestational age 27 weeks, birth weight 718 g). The patient had intrauterine growth retardation and developed hyperglycaemia on the first day of life. Insulin administration was discontinued on the 89th day of life, which was 1 day before the original due date. This case suggests that (a) insufficient insulin secretion started at least from the second trimester of the pregnancy; (b) the duration needed for recovery of insulin secretion was not dependent on the maturity.

Protein kinase A increases the tension cost and unloaded shortening velocity in skinned rat cardiac muscle.

To address controversies concerning the effect of beta-adrenergic stimulation on the rate of cross-bridge cycling in cardiac muscle, we measured ca(2+)-induced isometric tension development, unloaded shortening velocity (Vmax) and ATPase activity of demembranated (Triton X-100 skinned) rat right ventricular trabeculae before and after treatment with the catalytic subunit of protein kinase A (PKA), which is known to mimic the action of beta-adrenergic agonists in demembranated preparations. PKA treatment (1 U/microliter, 40 min) shifted the pCa-tension relation to the right from 5.41 to 5.26 at pCa50 (the [Ca2+] required for half maximal steady state tension) without changing the steepness of the pCa-tension relation and the maximum Ca(2+)-activated tension; Vmax, as determined by the slack test, was increased for a given pCa value, despite the reduced level of isometric tension. PKA treatment also shifted the pCa-ATPase activity to the right slightly from 5.47 to 5.40 at pCa50 (the [Ca2+] required for half maximal ATPase activity), but increased the ATPase activity during a given level of steady isometric tension generation, resulting in a 33% increase of the tension cost (ATPase activity/tension). All the results obtained strongly suggest that, in rat right ventricular trabeculae, beta-adrenergic stimulation may increase the rate of cross-bridge cycling by increasing the rate of cross-bridge detachment from actin through a PKA-mediated mechanism, although PKA reduces the Ca(2+)-sensitivity of the contractile system.

Toward molecular strategies for heart disease--past, present, future.

The past two decades of cardiovascular biology and medicine have been based largely upon the consideration of the heart and vasculature as an integrated physiological system, a view that has resulted in major therapeutic advances. With the advent of developments of gene transfer, mouse and human genetics, genetic engineering of intact animals, and molecular and cellular technology, cardiovascular medicine is now on the threshold of a molecular therapeutic era. Major steps have been taken toward unraveling the molecular determinants of complex, integrative, and polygenic cardiovascular disease states, including atherogenesis, hypertension, cardiac hypertrophy and failure, congenital heart disease, and coronary restenosis following balloon angioplasty. Our improved understanding of the fundamental basis of these important cardiovascular disease processes has established a scientific foundation for diagnostic, prognostic, and therapeutic advances in the mainstream of cardiovascular medicine.

[A case of neuroleptic malignant syndrome developed in liver cirrhosis patient addicted to alcohol].

A 55-year-old man with addiction of alcohol was admitted to our hospital with hematoemesis. After admission, the rupture of esophageal varices was observed and it was treated with endoscopic injection sclerotherapy. On the 3rd hospital day, the patient showed alcohol withdrawal syndrome and therefore haloperidol was administered intramuscularly and intravenously. After a half day of this treatment, high fever, diaphoresis, hypotension, tachycardia, muscular rigidity and tremor developed. With the laboratory data including high serum levels of CK, LDH, GOT and GPT, neuroleptic malignant syndrome (NMS) was suspected. Regardless of intensive care, hepatic failure, DIC and acute renal failure promptly developed, and he died on the 11th hospital day. Neuroleptics may cause serious side effects, such as NMS, when the physical status of patients was deteriorated. Especially in exhausted patient such as our case, even the small dose of neuroleptics caused NMS within short term. Thus, it seemed to be important for clinicians to pay attention to choice of neuroleptics.

A post-transcriptional compensatory pathway in heterozygous ventricular myosin light chain 2-deficient mice results in lack of gene dosage effect during normal cardiac growth or hypertrophy.

Our previous study of homozygous mutants of the ventricular specific isoform of myosin light chain 2 (mlc-2v) demonstrated that mlc-2v plays an essential role in murine heart development (Chen, J., Kubalak, S. W., Minamisawa, S., Price, R. L., Becker, K. D., Hickey, R., Ross, J., Jr., and Chien, K. R. (1998) J. Biol. Chem. 273, 1252-1256). As gene dosage of some myofibrillar proteins can affect muscle function, we have analyzed heterozygous mutants in depth. Ventricles of heterozygous mutants displayed a 50% reduction in mlc-2v mRNA, yet expressed normal levels of protein both under basal conditions and following induction of cardiac hypertrophy by aortic constriction. Heterozygous mutants exhibited cardiac function comparable to that of wild-type littermate controls both prior to and following aortic constriction. There were no significant differences in contractility and responses to calcium between wild-type and heterozygous unloaded cardiomyocytes. We conclude that heterozygous mutants show neither a molecular nor a physiological cardiac phenotype either at base line or following hypertrophic stimuli. These results suggest that post-transcriptional compensatory mechanisms play a major role in maintaining the level of MLC-2v protein in murine hearts. In addition, as our mlc-2v knockout mutants were created by a knock-in of Cre recombinase into the endogenous mlc-2v locus, this study demonstrates that heterozygous mlc-2v cre knock-in mice are appropriate for ventricular specific gene targeting.

Down-regulation of sarcolipin mRNA expression in chronic atrial fibrillation.

BACKGROUND: Abnormal intracellular Ca2+ homeostasis is an important modulator of chronic atrial fibrillation. Sarcolipin, a homologue of phospholamban, is specifically expressed in the atria, and may play an important role in modulating intracellular Ca2+ homeostasis in the atria. The aim of this study was to investigate the expression of sarcolipin mRNA in the atrial myocardium of patients with chronic atrial fibrillation. METHODS: We analyzed the expression of sarcolipin, phospholamban, cardiac calsequestrin and sodium calcium exchanger mRNAs in the right atrial myocardium from nine patients with mitral valvular disease with atrial fibrillation (MVD/AF), nine patients with MVD who had normal sinus rhythm (MVD/NSR), and 10 control patients with normal sinus rhythm who received open heart surgery (controls). The expression of mRNA was measured using the ABI PRISM 7700 Sequence Detection System (Applied Biosystems, Foster City, CA). RESULTS: Relative expression levels of sarcolipin mRNA were significantly lower in MVD/AF (0.60 +/- 0.11) than in either MVD/NSR (1.28 +/- 0.17, P < 0.01) or controls (1.10 +/- 0.10, P < 0.05). The expression levels of sarcolipin mRNA were significantly lower in the group with high values for right atrial pressure. The expression levels of phospholamban, cardiac calsequestrin and sodium calcium exchanger mRNAs were comparable among all three groups. CONCLUSIONS: Chronic electrical and mechanical overload decreased the expression of sarcolipin mRNA in the right atrial myocardium in patients with chronic atrial fibrillation. Down-regulation of sarcolipin mRNA may be part of atrial fibrillation-induced atrial remodelling.

Selective requirement of myosin light chain 2v in embryonic heart function.

Two major myosin light chain 2 isoforms are coexpressed in the early stages of murine cardiogenesis, a cardiac ventricular isoform and a cardiac atrial isoform, each of which is tightly regulated in a muscle cell-type-specific manner during embryogenesis (Chien, K. R., Zhu, H., Knowlton, K. U., Miller-Hance, W., van Bilsen, M., O'Brien, T. X., and Evans, S. M. (1993) Annu. Rev. Physiol. 55, 77-95). We have disrupted myosin light chain 2v gene in mice and monitored in vivo cardiac function in living myosin light chain 2v -/- embryos. The mutant embryos die at approximately embryonic day 12.5. In mutant ventricles, the myosin light chain 2a protein level is increased and reaches levels comparable to the myosin light chain 2v in the ventricles of wild type littermates and is appropriately incorporated into the thick filaments of mutant embryonic hearts. However, despite the substitution of myosin light chain 2a, ultrastructural analysis revealed defects in sarcomeric assembly and an embryonic form of dilated cardiomyopathy characterized by a significantly reduced left ventricular ejection fraction in mutant embryos compared with wild type littermates. We conclude that myosin light chain 2v may have a unique function in the maintenance of cardiac contractility and ventricular chamber morphogenesis during mammalian cardiogenesis and that a chamber-specific combinatorial code for sarcomeric assembly may exist that ultimately requires myosin light chain 2v in ventricular muscle cells.

Chronic phospholamban-sarcoplasmic reticulum calcium ATPase interaction is the critical calcium cycling defect in dilated cardiomyopathy.

Dilated cardiomyopathy and end-stage heart failure result in multiple defects in cardiac excitation-contraction coupling. Via complementation of a genetically based mouse model of dilated cardiomyopathy, we now provide evidence that progressive chamber dilation and heart failure are dependent on a Ca2+ cycling defect in the cardiac sarcoplasmic reticulum. The ablation of a muscle-specific sarcoplasmic reticulum Ca2+ ATPase (SERCA2a) inhibitor, phospholamban, rescued the spectrum of phenotypes that resemble human heart failure. Inhibition of phospholamban-SERCA2a interaction via in vivo expression of a phospholamban point mutant dominantly activated the contractility of ventricular muscle cells. Thus, interfering with phospholamban-SERCA2a interaction may provide a novel therapeutic approach for preventing the progression of dilated cardiomyopathy.

A novel genetic pathway for sudden cardiac death via defects in the transition between ventricular and conduction system cell lineages.

HF-1 b, an SP1 -related transcription factor, is preferentially expressed in the cardiac conduction system and ventricular myocytes in the heart. Mice deficient for HF-1 b survive to term and exhibit normal cardiac structure and function but display sudden cardiac death and a complete penetrance of conduction system defects, including spontaneous ventricular tachycardia and a high incidence of AV block. Continuous electrocardiographic recordings clearly documented cardiac arrhythmogenesis as the cause of death. Single-cell analysis revealed an anatomic substrate for arrhythmogenesis, including a decrease and mislocalization of connexins and a marked increase in action potential heterogeneity. Two independent markers reveal defects in the formation of ventricular Purkinje fibers. These studies identify a novel genetic pathway for sudden cardiac death via defects in the transition between ventricular and conduction system cell lineages.