Expression of inducible nitric oxide synthase, nitric oxide and salivary oxidized LDL as early markers of severe dengue

Abstract ObjectivesTo identify suitable biomarkers during early stages of dengue to predict which patients would develop severe forms of dengue before the warning signs appear. MethodsExpression of inducible nitric oxide synthase (iNOS) and resultant changes in nitric oxide (NO) and oxidized low density lipoprotein (oxLDL) levels in plasma and saliva were analyzed. ResultsExpression of iNOS in patients who later developed dengue hoemorrhagic fever (DHF) showed significant (P<0.05) down regulation compared to dengue fever (DF) patients while those who later developed DHF showed a corresponding significant (P<0.05) decrease of plasma NO levels (18.1±3.1 μM) compared to DF patients (23.6±4.4 μM) within 4 days from fever onset. OxLDL levels in plasma showed a decrease in patients who later developed DHF compared to DF patients although this value was significantly different only within 3 days from fever onset. The salivary NO levels did not show a significant difference. However, salivary oxLDL levels were significantly (P<0.05) low in patients who later developed DHF (0.6±0.2 ng/mL) compared to DF patients (1±0.4 ng/mL) collected within 4 days from fever onset. ConclusionsThe expression level of iNOS, plasma NO and salivary oxLDL levels may serve as early markers of severity of dengue infection. HighlightSeverity of dengue infection correlates with early differential expression of iNOSPlasma NO and salivary oxLDL levels may also serve as early markers of severe dengueSaliva may serve as a non-invasive source of early biological markers for severity of dengue infection