Plasma LDH: A specific biomarker for lung affectation in COVID-19?

Area of Science:

• Biochemistry
• Infectious Diseases
• Pulmonology

Background:

• Lactate dehydrogenase (LDH) levels are often elevated in COVID-19 patients.
• LDH isoenzyme 3 (LDH-5) is predominantly found in lung tissue.
• The specific contribution of LDH isoenzymes to elevated plasma LDH in COVID-19 remains unclear.

Purpose of the Study:

• To investigate alterations in plasma lactate dehydrogenase (LDH) isoenzyme profiles in COVID-19 patients.
• To determine if elevated LDH in COVID-19 is associated with increased LDH-3, the primary lung isoenzyme.
• To assess the utility of LDH as a specific biomarker for lung involvement in COVID-19.

Main Methods:

• Plasma samples were collected from 17 COVID-19 patients and 7 healthy controls.
• Electrophoresis and densitometry were used to analyze the relative activity of LDH isoenzymes.
• Correlations between LDH isoenzyme activity and clinical parameters were examined.

Main Results:

• Total plasma LDH activity was significantly higher in COVID-19 patients compared to controls.
• No significant differences were observed in the relative activities of individual LDH isoenzymes between patients and controls.
• No correlation was found between total LDH activity, LDH-3 levels, and various hematological/serum markers associated with COVID-19.

Conclusions:

• The elevation of plasma LDH in COVID-19 patients is not attributable to a specific release of LDH-3.
• LDH is not a specific biomarker for lung damage in COVID-19.
• Further research may explore other biomarkers for assessing lung involvement in COVID-19.