Use of serum creatine kinase MM isoforms for predicting the progression of left ventricular dilation in patients with hypertrophic cardiomyopathy

High levels of brain-type creatine kinase activity in human platelets and leukocytes: a genetic anomaly with autosomal dominant inheritance

The ectopic expression in peripheral blood cells of the brain-type creatine kinase (CKB) is an autosomal dominant inherited anomaly named CKBE (MIM ID 123270). Here, we characterized the CK activity in serum, platelets (PLT) and leukocytes (WBC) of 22 probands (from 8 unrelated families) and 10 controls. CK activity was measured by standard UV-photometry. Expression of the CKB gene was analyzed by real-time PCR and Western blotting. DNA sequencing including bisulfite treatment was used for molecular analysis of the CKB gene. Serum CK levels were comparable between probands and controls. CKBE probands revealed significantly higher CK activity in PLT (3.7 ± 2.7 versus 179.2 ± 83.0 U/10(12) PLT; p<0.001) and WBC (0.4 ± 0.3 versus 2.6 ± 2.1 U/10(9) WBC; p=0.004). Inhibitory anti-CKM antibodies did not affect CK activity indicating that the CK activity is generated exclusively by the CK-BB isoenzyme. CKB mRNA and protein levels were significantly higher in PLT and WBC from probands compared to controls. Re-sequencing of the entire CKB gene and methylation analysis of a CpG island revealed no alteration in CKBE probands. The genetic basis of CKBE remains unclear, however, we propose that a de-methylated CKB gene is inherited that leads to high CKB expression levels in myeloic precursor cells in the bone marrow.

Biochemical markers of muscular damage

Muscle tissue may be damaged following intense prolonged training as a consequence of both metabolic and mechanical factors. Serum levels of skeletal muscle enzymes or proteins are markers of the functional status of muscle tissue, and vary widely in both pathological and physiological conditions. Creatine kinase, lactate dehydrogenase, aldolase, myoglobin, troponin, aspartate aminotransferase, and carbonic anhydrase CAIII are the most useful serum markers of muscle injury, but apoptosis in muscle tissues subsequent to strenuous exercise may be also triggered by increased oxidative stress. Therefore, total antioxidant status can be used to evaluate the level of stress in muscle by other markers, such as thiobarbituric acid-reactive substances, malondialdehyde, sulfhydril groups, reduced glutathione, oxidized glutathione, superoxide dismutase, catalase and others. As the various markers provide a composite picture of muscle status, we recommend using more than one to provide a better estimation of muscle stress.

Prognostic value of elevated circulating heart-type fatty acid binding protein in patients with congestive heart failure

BACKGROUND

Heart-type fatty acid binding protein (H-FABP) is released into the circulation when the myocardium is injured and is a novel marker for the diagnosis of acute myocardial infarction. The purpose of the present study was to examine the clinical significance of increased serum H-FABP levels in patients with congestive heart failure.

METHODS AND RESULTS

Serum levels of H-FABP were measured in 179 patients admitted with congestive heart failure and 20 age-matched normal controls by using a sandwich enzyme-linked immunosorbent assay. Patients were prospectively followed during a mean follow-up period of 20 months with the end points of cardiac death and progressive heart failure requiring rehospitalization. Serum levels of H-FABP were higher in patients with congestive heart failure than in control subjects (5.7 +/- 4.8 ng/mL versus 2.7 +/- 0.8 ng/mL, P < .01) and increased with advancing NYHA class (P < .01). The cardiac event rate was markedly higher in patients with elevated H-FABP levels than in those with normal levels (43% versus 7%, P < .0001). Furthermore, the Cox multivariate proportional hazard analysis revealed that the elevated H-FABP level was the only independent predictor for cardiac events (chi2= 7.397, P < .01).

CONCLUSIONS

Elevation of H-FABP indicates latent and ongoing cardiomyocyte damage and identifies patients at high risk for future cardiac events in congestive heart failure.

Circulating levels of heart-type fatty acid-binding protein and its relation to thallium-201 perfusion defects in patients with hypertrophic cardiomyopathy

Myocyte loss and replacement fibrosis have been observed in patients with hypertrophic cardiomyopathy (HC) with heart failure. This study was designed to elucidate whether heart-type fatty acid-binding protein (H-FABP), a sensitive biochemical marker for myocardial damage, indicates ongoing myocardial damage in patients with HC. We studied 48 patients with HC and 17 control subjects. Patients with HC were divided into 2 groups according to the New York Heart Association (NYHA) functional class: NYHA I + II (n = 40) and NYHA III + IV (n = 8). Serum H-FABP and myoglobin levels were measured, and extent score was used to assess the extent of thallium-201 perfusion defect. Serum H-FABP levels were significantly higher in patients with HC than in control subjects (3.8 +/- 1.6 vs 2.6 +/- 0.7 ng/ml, p = 0.0032). Furthermore, serum H-FABP levels were significantly higher in NYHA III + IV than in NYHA I + II (5.2 +/- 1.3 vs 3.5 +/- 1.5 ng/ml, p = 0.0043). Serum myoglobin levels showed no significant difference among the 3 groups (control, 46.6 +/- 15.0 ng/ml; NYHA I + II, 55.5 +/- 26.4 ng/ml; NYHA III + IV, 65.1 +/- 33.6 ng/ml, p = 0.2115). Extent score correlated positively with serum H-FABP levels (r = 0.420, p = 0.0026) and negatively with fractional shortening (r = -0.542, p <0.0001). Increased H-FABP levels indicate ongoing myocardial damage, which could result in clinical deterioration in patients with HC.

Retrospective Review: The Incidence of Non-ST Segment Elevation MI in Emergency Department Patients Presenting With Decompensated Heart Failure

The authors performed a 6-month review of heart failure patients presenting to a teaching hospital emergency department to determine the rate of positive serum myocardial infarction markers. All patients with an emergency department discharge diagnosis of heart failure were included; those with a creatinine level >2.0 mg/dL were excluded. There were 151 patients who met the entry criteria, with a mean age of 68.6 +/- 13.6 years, and 84 (56%) were men. The mean ejection fraction was 32%, and the mean Framingham score was 3.8 +/- 1.6. Twenty (14%) had positive markers. Troponin T was positive in 17 (11%), and creatine kinase was positive in nine (6%). Both markers were positive in six (4%). Chest pain was absent in 70% of the positive marker group. The authors conclude that elevated cardiac markers are not rare in decompensated heart failure. These pilot data suggest these tests should be routinely obtained on heart failure patients.