Identifying Complications in Sickle Cell Patients

An enzyme, lactose dehydrogenase (LDH) has been proposed as a marker for risk of pulmonary hypertension and other complications in patients with sickle cell disease. The enzyme can be measured by a simple blood test.

Pulmonary hypertension--abnormally high blood pressure in the lungs--is common in sickle cell disease, a hereditary blood disorder characterized by an abnormal type of hemoglobin that distorts the shape of erythrocytes and interferes with blood flow. Patients with sickle cell disease need to be carefully monitored for pulmonary hypertension, which is a life-threatening condition.

A study of levels of LDH in sickle cell patients and frequency of complications conducted by researchers at the National Institutes of Health Clinical Center and the National Heart, Lung, and Blood Institute (both in Bethesda, MD, USA) appears in the March issue of "Blood.” The enzyme LDH investigated in the study is found throughout the body, especially in red blood cells, the heart, the liver, the lungs, and muscle. A blood test measuring LDH levels is commonly available to determine tissue damage due to a variety of causes.

The study found that patients with the highest level of LDH were more likely to experience pulmonary hypertension, leg ulcerations, and priapism. Pulmonary hypertension was detected in 61% of patients with high LDH compared to 15% of patients in the lowest LDH group. Patients with high LDH levels were more likely to experience early death than those with lower LDH levels. The high levels of LDH appear to indirectly indicate that hemoglobin and arginase have escaped from erythrocytes, which might help to explain why pulmonary hypertension develops in sickle cell disease.

Dr. Gregory Kato, who lead the study, explained, "When fragile cells rupture and release their contents into the bloodstream, after years it may cause blood vessel walls to become diseased.” He concluded, "Our recent current findings further support this theory. Learning more about this chain of events will help us to identify additional potential treatments.”



Related Links:
National Institutes of Health Clinical Center