Role of ischemia-modified albumin in clinical practice

The diagnostic potential of oxidative stress biomarkers for preeclampsia: systematic review and meta-analysis

BACKGROUND

Preeclampsia is a multifactorial cardiovascular disorder of pregnancy. If left untreated, it can lead to severe maternal and fetal outcomes. Hence, timely diagnosis and management of preeclampsia are extremely important. Biomarkers of oxidative stress are associated with the pathogenesis of preeclampsia and therefore could be indicative of evolving preeclampsia and utilized for timely diagnosis. In this study, we conducted a systematic review and meta-analysis to determine the most reliable oxidative stress biomarkers in preeclampsia, based on their diagnostic sensitivities and specificities as well as their positive and negative predictive values.

METHODS

A systematic search using PubMed, ScienceDirect, ResearchGate, and PLOS databases (1900 to March 2021) identified nine relevant studies including a total of 343 women with preeclampsia and 354 normotensive controls.

RESULTS

Ischemia-modified albumin (IMA), uric acid (UA), and malondialdehyde (MDA) were associated with 3.38 (95% CI 2.23, 4.53), 3.05 (95% CI 2.39, 3.71), and 2.37 (95% CI 1.03, 3.70) odds ratios for preeclampsia diagnosis, respectively. The IMA showed the most promising diagnostic potential with the positive predictive ratio (PPV) of 0.852 (95% CI 0.728, 0.929) and negative predictive ratio (NPV) of 0.811 (95% CI 0.683, 0.890) for preeclampsia. Minor between-study heterogeneity was reported for these biomarkers (Higgins' I2 = 0-15.879%).

CONCLUSIONS

This systematic review and meta-analysis identified IMA, UA, and MDA as the most promising oxidative stress biomarkers associated with established preeclampsia. IMA as a biomarker of tissue damage exhibited the best diagnostic test accuracy. Thus, these oxidative stress biomarkers should be further explored in larger cohorts for preeclampsia diagnosis.

Protective role of antithrombin III in suppressing acute responses in a rat model of renal ischemia-reperfusion injury

Renal ischemia-reperfusion (IR) produces-induced injury and is characterized by restriction of blood supply to the kidney followed by restoration and re-oxygenation of the tissue. IR injury in the kidney contributes to pathological processes known as acute renal injury (ARI). Ischemia-perfusion injury (IRI) of the left renal artery has been demonstrated in Wistar rats. A total of 32 animals were divided into four groups: control group (SHAM), IR animals with induced ischemia-reperfusion, AT-IR animals treated by antithrombin III (AT) before IR, and AT-IR-AT animals with AT administered before and after IR. IR-induced hyperproteinemia, hyperalbuminemia, hyperglobulinemia, and a significantly low A/G ratio. Exogenous administration of AT prior to IR development effectively regulates protein fraction levels by establishing normoproteinemia. The preventive effect of AT regulates serum protein levels and reduces acute inflammation by reducing globulin and establishing physiological levels of A/G ratios. The therapeutic effect of AT given after IR is not effective compared to AT administered before IR. Protein fractions can serve as an important predictive marker for the prognosis and duration of acute inflammation. Serum globulin levels and the A/G ratio may serve as effective prognostic markers in acute inflammation caused by ischemia-reperfusion injury of the kidney. A strong correlation between globulin and the A/G ratio suggests novel markers associated with acute inflammation that can lead to chronic kidney disease.

Ischemia-Modified Albumin as a Marker of Acute Coronary Syndrome: The Case for Revising the Concept of "N-Terminal Modification" to "Fatty Acid Occupation" of Albumin

Ischemia-modified albumin (IMA) is assumed “N-terminal modified” albumin which is generated immediately following myocardial ischemia. The diagnosis of IMA is based on reduced cobalt binding affinity to albumin which is attributed mainly to incapability of cobalt to bind at albumin's modified N-terminus. Although the albumin cobalt binding test was accepted as a potentially powerful marker for discriminating acute coronary syndrome from nonischemic chest pain, its usefulness has been brought into question in recent years. Patients with acutely ischemic myocardium exhibit a rapid increase in serum levels of fatty acids (FAs). Almost all released FAs are strongly bound to albumin which create conformational changes in the protein with resultant reduced cobalt binding affinity. There is a clear metabolic and temporal relationship between IMA measured via albumin cobalt binding testing and serum levels of FAs. In line with what has been suggested recently in the literature, we conclude that a shift from the concept of “N-terminal modified” to “FA-occupied” albumin is required, as this better describes IMA in patients with acute coronary syndrome. We also offer “oxidation modified albumin, OMA,” which is conceptually different from the “FA-occupied” IMA, to describe modification of albumin in chronic disease associated with increased oxidative stress.