Cardiovascular diseases are considered the leading cause of mortality among hemodialysis patients. Hypertension, advanced age, diabetes, and other systemic diseases that affect cardiac function are commonly seen in these patients. This article will examine the effects of carnitine on hemodialysis patients.
Additionally, hemodialysis patients often suffer from deficiencies in some essential substances required for the metabolic functions of myocardial cells.
Introduction to Carnitine
Carnitine is a natural substance with its primary physiological role in the body:
It facilitates the transport of long-chain fatty acids from the cytoplasm into mitochondria for their beta-oxidation.
Therefore, sufficient carnitine within cells is essential for the normal metabolism of fatty acids in the human body. This is especially important in tissues like the heart and skeletal muscles, which depend on fatty acid metabolism to produce energy.
Key Features and Roles of Carnitine
- Fat Metabolism: Carnitine plays a role in transporting fatty acids into mitochondria for beta-oxidation (the process of producing energy from fatty acids). This process is essential for energy production in daily activities.
- Support for the Cardiovascular System: The heart, as the main blood pump in the human body, requires a constant supply of energy. Carnitine helps by transporting fatty acids into the mitochondria of the myocardium (heart muscle), improving energy supply and potentially improving cardiovascular function.
- Regulation of Glucose Metabolism: The breakdown of fats by carnitine can help reduce glucose utilization as an energy source, which may be beneficial in improving blood sugar control.
- Oxidative Balance: Carnitine acts as a natural antioxidant, helping to maintain oxidative balance within cells and preventing oxidative damage.
- Body Composition Support: Carnitine supplementation can help reduce abdominal fat and improve overall body composition.
Biological Function in Humans
In the human biological system, carnitine exists in two forms:
- Free form
- Esterified form
In hemodialysis patients, unlike healthy individuals, the esterified form of carnitine is more prevalent than the free form. This is due to the loss of free carnitine through the dialysis membrane. As a result, despite normal plasma levels of total carnitine, the accumulation of the esterified form and the reduction in free carnitine leads to lower carnitine levels in tissues (including the heart and skeletal muscles).
Effects of Carnitine Administration
Various studies have investigated the effects of carnitine administration (either intravenously or orally) in hemodialysis patients or those with heart failure. One such study found that carnitine had a significant effect on improving anemia in hemodialysis patients.
Effects of Low Dose Oral Carnitine Administration
A study conducted by researchers showed that administering a low dose of oral L-carnitine (500 mg per day) for six months resulted in improvement in:
- Patient symptoms
- Increased LVEF (Left Ventricular Ejection Fraction)
- Decreased left ventricular mass
Given the mixed results regarding the effects of carnitine on cardiac function, further studies are necessary to evaluate its impact on heart function.
Results on the Cardiac Systolic Function in Hemodialysis Patients with Heart Failure
This study, conducted on hemodialysis patients, examined the effect of oral carnitine administration on the systolic function of the heart in these patients with heart failure.
In addition, the impact of carnitine administration on:
- Cardiac symptoms
- Anemia
- Hyperlipidemia
was also assessed simultaneously in these patients. A total of 20 patients participated in the study, divided into control and intervention groups. They were studied for six months.
Inclusion criteria for the patients were having an LVEF (Left Ventricular Ejection Fraction) of less than 50%. Patients with heart failure due to other specific causes, such as congenital heart diseases or valvular heart disorders, were excluded from the study. After adjusting for variables such as:
- Age
- Gender
- Cause of kidney failure
- Hypertension
- Diabetes, etc.
patients were randomly assigned to the intervention and control groups.
Drug Administration to Patients
After selecting patients and dividing them into two groups (intervention and control), the intervention group was given 250 mg carnitine tablets with a dose of 1 gram per day.
The control group received a placebo in the same form as the carnitine but without carnitine.
Other medications commonly used by these patients, including:
- Rokatrol tablets
- Ferrous sulfate tablets
- Calcium carbonate tablets
- Folic acid tablets
- Eprex injections
- Antihypertensive medications
were continued, and no changes were made to the doses. Efforts were made to ensure the medication types were similar between the two groups.
Results Regarding Ejection Fraction
The results obtained regarding:
- Ejection fraction
- Left ventricular end-diastolic diameter
- The ratio of cardiac diameter to chest diameter on chest X-ray
- Hemoglobin levels
- Triglycerides
- Plasma cholesterol
were compared using repeated-measures analysis of variance and Bonferroni post-hoc tests. To compare between the two groups, Student’s t-test was used.
According to the studies, low-dose oral carnitine (500 mg/day for six months) significantly improved cardiac symptoms and function in hemodialysis patients.
Conclusion
The difference in the results of this study compared to previous research might be due to:
- The ejection fraction level, which in our study was set to less than 50%, whereas in the Matsumoto study it was set to less than 60%. This means the cardiac function of patients in our study was lower initially.
- The carnitine dose in their study was almost half of the dose used in our study.
Another study examined the effect of intravenous carnitine on serum triglyceride levels and showed that carnitine is effective only in patients with hypertriglyceridemia.
Research Results
According to the studies, only oral carnitine has a significant and beneficial effect on improving anemia. Researchers found that carnitine helps:
- Reduce fatigue
- Increase exercise tolerance
Given the importance of cardiovascular problems in hemodialysis patients, which is the leading cause of mortality in these patients, further studies are necessary to evaluate the effect of carnitine in improving the cardiac condition of these patients.