Salivary uric acid simple non invasive test to monitor women with preeclampsia: Study
Preeclampsia considered a gestational hypertension with proteinuria (either 300 mg/24 hours or ≥ 30mg/dL (≥1+ on dipstick) in form of about two urine samples taken 6 hours between each, no more than 7 days apart.
Preeclampsia is classified into mild form (where Blood pressure usually shown ≥ 140/90 taken twice with 6 hours interval between each reading with associated Protein in urine ≥ 300mg/24hr or ≥ 1 + on 2 urine samples 6 hours apart, or severe form (where Blood Pressure usually shown ≥ 160/110 taken twice with 6 hours interval between each reading with associated Protein in urine ≥ 5g/24hr or ≥ 3+ on 2 urine samples 6 hours apart, important findings that can be or not be part of the presentation like proteinuria, signs of organ impairment, such as decrease platelets count, hepatic function impairment, epigastric and right hypochondrial persistent sever pain, recently onset headache not responding to treatment, pulmonary edema, or renal impairment.
Preeclampsia Pathogenesis is not fully understood still researches done to make a progress in this dilemma in the last decades. The placenta plays the major role in the pathogenesis of preeclampsia. Thus, the model of two-stage was appear: partial remodeling of spiral artery in the uterus that leads to ischemia in placental tissue (stage 1) and the release of anti angiogenic factors from this tissue into thematernal circulation that leads to damage of endothelium (stage 2). These hypothesis may explain the hyperuricemia in early pregnancy with preeclampsia which precede hypertension and proteinuria.
Uric acid is a terminal degeneration produce by catalyzing of purine by the xanthine dehydrogenase/xanthine oxidase (XDH/XO) enzyme, and contributes to the blood and saliva. XDH is change to its oxidase form XO by many factors including ischemia. Metabolism of Purine by XO couples the production of uric acid and the release of the superoxide (O2) free radical and is implicated as a contributor to oxidative stress. XDH/XO is present in various tissue but mainly in the gut and liver and increases following ischemic tissue damage. Many studies revealed that uric acid may act as pro-inflammatory and pro-oxidant agent.
This study involved 180 patient divided into three group 60 patient healthy not pregnant women as control, 1st study group (A) 60 normotensive pregnant women in third trimester, 2nd study group (B) 60 patient diagnosed as PET both group in their third trimester of pregnancy, uric acid levels in both the serum & saliva was recorded by ELISA and the result was compared statistically. A cross-sectional study performed at AlYarmouk Teaching Hospital from October 2022 to October 2023.
The result showed when compared serum and salivary uric acid level in the three studying groups the mean of serum uric acid level were 46.65±6.76mg/dl, 50.03±6.28mg/dl, 63.31±3.61 mg/dl in the non pregnant, pregnant, pregnant with PET consequently with obvious difference P-value 0.0001. Salivary uric acid was significantly increased in the pregnant PET group mean level was (50.59-83.58mg/dl) in comparison with (33.95-63.11mg/dl)in non pregnant and (38.94- 66.93mg/dl) in pregnant group were the p- value 0.0001.
Uric acid level in the serum was found to be about 25–35% in uncomplicated pregnancies due to blood volume expansion related to pregnancy, high renal blood flow, high glomerular filtration rate and lastly due to uricosuric action of estrogen. Serum uric acid concentrations continue to rise as pregnancy proceed till the end of pregnancy, as a result of the increased fetal production, its albumin binding level decreased and with associated decrease renal clearance. In pregnancies complicated by preeclampsia, the decreased in uric acid excretion level, will subsequently increase the level of serum uric acid. Although uricemia is usually followed by proteinuria. Recent studies show increase in oxidative stress materials and reactive oxygen species the formation were all found to be another contributing resources for hyperuricemia observed in pregnant ladies complicated with preeclampsia. Due to the interaction between uric acid with proinflammatory cytokines, increased plasma levels of uric acid in pregnant women with preeclampsia may indicate a direct contribution for its pathophysiology as its role of action through promoting inflammation.
Salivary UA can be used as a simple non invasive test to monitor women with preeclampsia.
Source: Ismael et al. / Indian Journal of Obstetrics and Gynecology Research 2025;12(3):409–414
