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Myocardial lactate dehydrogenase subunit ratio in cardiac allograft recipients
B Albat1, E Missov, A M Boularan
1Service de Chirurgie Thoracique et Cardio-Vasculaire, Hôpital Arnaud de Villeneuve, Centre Hospitalier Universitaire de Montpellier, France.
Insights
Changes in the lactate dehydrogenase heart/muscle (H/M) ratio may signal early allograft coronary artery disease (CAD) in heart transplant patients. This metabolic shift indicates potential complications, aiding in early detection and management of allograft CAD.
Area of Science:
- Cardiology
- Transplantation Immunology
- Biochemistry
Background:
- Allograft coronary artery disease (CAD) is a significant long-term complication following heart transplantation.
- The precise metabolic underpinnings of allograft CAD require further investigation.
- Lactate dehydrogenase (LDH) isoenzyme patterns may offer insights into metabolic changes associated with allograft CAD.
Purpose of the Study:
- To investigate the utility of the lactate dehydrogenase heart (H) and muscle (M) isoenzyme ratio (H/M ratio) as an early indicator of allograft CAD.
- To analyze the evolution of the H/M ratio in heart transplant recipients over 12 months post-transplantation.
Main Methods:
- Twenty-four heart transplant recipients were monitored for 12 months, with endomyocardial biopsies at regular intervals.
- LDH isoenzymes (1-5) were separated by electrophoresis, and the H/M ratio was calculated.
- Patients were categorized into two groups: those without allograft CAD (n=20) and those with poor outcomes and evidence of allograft CAD (n=4).
Main Results:
- The H/M ratio was significantly higher in patients without allograft CAD at 6 and 12 months post-transplantation compared to those with CAD (p=0.01).
- In patients without allograft CAD, the H/M ratio increased over the 12-month study period (p=0.02).
- Conversely, the H/M ratio showed a non-significant decrease in patients with allograft CAD.
Conclusions:
- Alterations in the H/M ratio reflect a metabolic shift towards anaerobic metabolism.
- The H/M ratio serves as a potential early biomarker for detecting allograft CAD in heart transplant recipients.
Background:
Allograft coronary artery disease (CAD) is a major long-term complication in heart transplanted patients. However, the metabolic basis of allograft CAD remains to be fully elucidated. We analyzed the lactate dehydrogenase heart (H) and muscle (M) isoenzyme pattern in endomyocardial biopsy specimens and the evolution of the H/M ratio to test whether changes in this ratio could be the earliest manifestation of allograft CAD.
Methods:
Twenty-four heart transplant recipients were followed up for 12 months. Endomyocardial biopsy was performed at 1, 2, 3, 6, and 12 months after transplantation. Lactate dehydrogenase 1 through 5 isoenzymes were separated by electrophoresis, and the H/M ratio was calculated. Two groups of patients were identified: group 1 (n = 20), patients without allograft CAD; and group 2 (n = 4), patients with poor outcome (three deaths, 1 case of low cardiac output) and angiographic and histologic evidence of allograft CAD.
Results:
Both groups had similar H/M baseline values. The H/M ratio was higher (p = 0.01) in group 1 at 6 months (3.48 +/- 0.64 versus 2.17 +/- 0.43) and 12 months (3.76 +/- 0.92 versus 2.18 +/- 0.45) when compared with group 2. The H/M ratio increased from 2.78 +/- 0.89 at 1 month to 3.76 +/- 0.92 at 12 months (p = 0.02) in group 1 and decreased in group 2 (2.86 +/- 0.49 versus 2.18 +/- 0.45; not significant).
Conclusions:
Changes in H/M ratio reflect an anaerobic shift in the lactate dehydrogenase isoenzyme composition and can be taken as an early indicator of allograft CAD.