Ischemia-modified albumin levels in overt and subclinical hypothyroidism

Independent correlation between ischemia modified albumin and parathormone in hemodialysis patients

Introduction. Hemodialysis patients are the group which oxidative stress is found more exacerbated. Ischemia modified albumin (IMA) is a new and sensitive marker for ischemia and oxidative stress. At current study we evaluated relation between IMA and biochemical parameters in hemodialysis patients. Materials and Methods. Thirty-four patients on maintenance hemodialysis were included. Pre-hemodialysis and post-hemodialysis blood samples were taken. Serum IMA and biochemistry parameters were measured. Results. There was a positive correlation between alkaline phosphatase (ALP) and IMA (r=0,268, p<0,05), CRP and IMA (r=0,452, p=0,007), parathormone and IMA (r=0,436, p=0,010), There was a negative correlation between albumin and IMA (r=-0,338, p=0,05). Multiple regression analysis was run to predict IMA levels from parathormone, CRP and creatinine the model statistically significantly predicted relation p<0,05, R=0,506, out of four two variables added statistically significant to the prediction, PTH (p=0,006), CRP (p=0,029). In multiregression analysis, IMA was found to be associated with PTH and CRP independent of creatinine value. Conclusions. We showed for the first time that PTH is associated with IMA in hemodialysis patients, independent of the level of renal function.

Independent correlation between ischemia modified albumin and parathormone in hemodialysis patients

Introduction. Hemodialysis patients are the group which oxidative stress is found more exacerbated. Ischemia modified albumin (IMA) is a new and sensitive marker for ischemia and oxidative stress. At current study we evaluated relation between IMA and biochemical parameters in hemodialysis patients. Materials and Methods. Thirty-four patients on maintenance hemodialysis were included. Pre-hemodialysis and post-hemodialysis blood samples were taken. Serum IMA and biochemistry parameters were measured. Results. There was a positive correlation between alkaline phosphatase (ALP) and IMA (r=0,268, p<0,05), CRP and IMA (r=0,452, p=0,007), parathormone and IMA (r=0,436, p=0,010), There was a negative correlation between albumin and IMA (r=-0,338, p=0,05). Multiple regression analysis was run to predict IMA levels from parathormone, CRP and creatinine the model statistically significantly predicted relation p<0,05, R=0,506, out of four two variables added statistically significant to the prediction, PTH (p=0,006), CRP (p=0,029). In multiregression analysis, IMA was found to be associated with PTH and CRP independent of creatinine value. Conclusions. We showed for the first time that PTH is associated with IMA in hemodialysis patients, independent of the level of renal function.

Meta-analytic evidence for increased low-grade systemic inflammation and oxidative stress in hypothyroid patients. Can levothyroxine replacement therapy mitigate the burden?

PURPOSE

This series of meta-analyses were aimed to elucidate the impact of hypothyroidism on low-grade systemic inflammation and oxidative stress assessed by C-reactive protein (CRP) and malondialdehyde (MDA) respectively; and to evaluate the effect of levothyroxine replacement therapy (LRT) on those outcomes.

METHODS

PubMed database and the key studies references were searched prior to March 3, 2020. Data on serum or plasma CRP and MDA levels in SHT (subclinical) and/or OHT (overt) hypothyroid patients and controls were extracted to compute overall standardized mean differences (SMD) by the random-effects model.

RESULTS

A total of 93 studies were entered into analyses and ten main meta-analyses were performed. OHT (SMD = 0.72 [0.39; 1.04], k = 35), SHT (SMD = 1.58 [0.78; 2.38], k = 56) and even mild SHT (TSH < 10 mU/L, SMD = 2.19 [0.02; 4.37], k = 13) proved to have a detrimental effect on CRP levels. LRT showed a favorable effect on CRP levels, particularly in OHT (SMD = -0.30 [-0.57; -0.02], k = 17). Increased levels of MDA were also found, especially in OHT (SMD = 2.49 [0.66; 4.31], k = 13). LRT may also improve MDA levels; however future studies would further validate the advantageous effect of LRT in hypothyroidism. Heterogeneity primarily originated from different study designs and geographic locations.

CONCLUSION

Overall, these meta-analyses reveal that screening for hs-CRP and MDA in hypothyroid patients as simple biomarkers of low-grade systemic inflammation and oxidative stress may become a useful tool to identify those at increased risk who may benefit most from early interventions.

Serum levels of advanced glycation end products (AGEs) are increased and their soluble receptor (sRAGE) reduced in Hashimoto's thyroiditis

PURPOSE

Advanced glycation end products (AGEs) are increased in conditions of oxidative stress and promote inflammation by interacting with their receptor RAGE on cell membrane. By contrast, the soluble receptor sRAGE exerts protective effects by competing with RAGE for ligand binding. AGEs/sRAGEs interaction is involved in the pathogenesis of several diseases related to oxidative stress. In the present study, we evaluated the AGEs/sRAGEs oxidative balance in Hashimoto' thyroiditis (HT).

METHODS

We measured the levels of sRAGE, by ELISA, and AGEs, by spectrophotometric method, in the serum of 50 HT patients (5 M, 45 F; mean age 38.5 ± 12 years) and 50 age-, sex- and BMI-matched healthy controls. All subjects were euthyroid at recruitment and none was on LT-4 therapy.

RESULTS

Serum sRAGEs were significantly lower (median 424 vs 738 pg/ml; p = 0.001) and AGEs higher (205 vs 114 AU/g prot; p = 0.001) in HT patients compared to controls, and the two parameters were inversely correlated (p = 0.016). Accordingly, the AGEs/sRAGEs ratio was threefold higher in HT patients than controls (0.48 vs 0.15; p = 0.0001). In regression analysis models, serum TPO-Ab were the main predictors for AGEs and sRAGEs levels and AGEs/sRAGEs ratio (p < 0.0001), irrespective of TSH and/or FT4 values.

CONCLUSION

sRAGEs were decreased and AGEs increased, suggesting a dysregulation of AGE/sRAGEs-related oxidative homeostasis in HT patients, even when in euthyroid status. Autoimmunity per se seems to play an important role in AGEs/sRAGE imbalance, irrespective of thyroid function alterations.

Status of Ischemia Modified Albumin in Athletes Before and After Moderate Exercise

Background:

Ischemia Modified Albumin (IMA) is considered as an early marker of ischemia. Its levels may be altered in any clinical condition where an ischemic event is involved. Skeletal muscle ischemia is associated with severe exercise but may also occur in moderate form of exercise.

Objective:

The levels of IMA were estimated before and after thirty minutes of moderate exercise in students undergoing athletic training.

Methods:

The present study was conducted on 120 young adult students undergoing athletic training program in the physical education department. All the subjects were healthy with normal body mass index and blood pressure. Their serum samples were collected before and after running for half an hour on the racing track and were analyzed for IMA colorimetrically and the data was subjected to appropriate statistical analysis.

Results:

The levels of IMA were found to be statistically significantly higher after exercise as compared to those before exercise (p = 0.005). The ratio of IMA to albumin (IMAR) was also found to be significantly higher after exercise as compared to that before exercise (p=0.000).

Conclusion:

It may be concluded that the skeletal muscle ischemia induced by moderate aerobic exercise is associated with an increased conversion of albumin to IMA.

Maternal serum and fetal cord-blood ischemia-modified albumin concentrations in normal pregnancy and preeclampsia: a systematic review and meta-analysis

BACKGROUND/AIMS

A meta-analysis of maternal serum ischemia-modified albumin (IMA) and fetal cord-blood IMA concentrations in normal pregnancy (NP) compared to non-pregnant healthy controls (HC) and in preeclampsia (PE) compared with normal pregnant controls were studied.

METHODS

All major databases were searched for eligible studies. We included eight studies comparing serum IMA between NP and HC, 14 studies comparing serum IMA between PE and NP and five studies comparing cord-blood IMA between PE and NP groups. Meta-analyses on these included studies were performed using Review Manager 5.3. Pooled-overall effect size as standardized mean difference (SMD), publication bias, subgroup, and sensitivity analysis data were generated.

RESULTS

Random-effects meta-analysis indicated a significant increase in serum IMA in the NP group (SMD = 0.98, p = .01) and the PE group (SMD = 0.94, p < .0001) as compared with HC and NP groups, respectively. And, the cord-blood IMA has been found to be significantly increased in PE (SMD = 6.51, p < .0001) compared with the NP group.

CONCLUSIONS

This meta-analysis, the first of its kind showed that the increased serum IMA concentrations were indicative of increased oxidative stress in NP and PE. Measurement of maternal serum IMA and fetal cord-blood IMA concentrations were useful as simple, novel, and inexpensive markers of oxidative stress (OS) status in PE patients. Future large-scale studies are needed to explore IMA in relationship to the disease severity in PE.

Elevated levels of the circulatory ischemia-modified albumin in patients with polycystic ovary syndrome: a meta-analysis

Oxidative stress (OS) has been reported to be associated with the pathogenesis of polycystic ovary syndrome (PCOS). Ischemia-modified albumin (IMA) levels in the circulation have been recently studied as a novel marker of OS. The studies in the literature on IMA levels in PCOS are inconsistent. This meta-analysis was conducted to compare circulatory IMA levels between PCOS patients and non-PCOS controls. Relevant studies were retrieved by online database and manual searching. The standardized mean differences (SMDs) with 95% confidence intervals (CIs) were obtained by a random-effects meta-analysis. The funnel plot analysis with Begg's and Egger's tests was used for publication bias. A total of nine studies were included in this meta-analysis. The results indicated that the serum IMA levels were significantly elevated in PCOS patients as compared to non-PCOS controls (SMD = 0.49, 95% CI = 0.23-0.75, Z = 3.75, p = .0002). A one-study leave-out sensitivity analysis indicated that no single study had a significant influence on the overall outcome, suggesting the good validity and stability of these meta-analytic results. There was no evidence of publication bias as evidenced by the Egger (p = .28) and Begg's tests (p = .21). The present meta-analysis suggests that IMA might be considered as a reliable and novel marker reflecting increased OS in PCOS.

Ischemia-modified albumin: Crosstalk between fatty acid and cobalt binding

Myocardial ischemia is difficult to diagnose effectively with still few well-defined biochemical markers for identification in advance, or in the absence of myocardial necrosis. "Ischemia-modified albumin" (IMA), a form of albumin displaying reduced cobalt-binding affinity, is significantly elevated in ischemic patients, and the albumin cobalt-binding (ACB) assay can measure its level indirectly. Elucidating the molecular mechanism underlying the identity of IMA and the ACB assay hinges on understanding metal-binding properties of albumin. Albumin binds most metal ions and harbours four primary metal binding sites: site A, site B, the N-terminal site (NTS), and the free thiol at Cys34. Previous efforts to clarify the identity of IMA and the causes for its reduced cobalt-binding capacity were focused on the NTS site, but the degree of N-terminal modification could not be correlated to the presence of ischemia. More recent work suggested that Co2+ ions as used in the ACB assay bind preferentially to site B, then to site A, and finally to the NTS. This insight paved the way for a new consistent molecular basis of the ACB assay: albumin is also the main plasma carrier for free fatty acids (FFAs), and binding of a fatty acid to the high-affinity site FA2 results in conformational changes in albumin which prevent metal binding at site A and partially at site B. Thus, this review advances the hypothesis that high IMA levels in myocardial ischemia and many other conditions originate from high plasma FFA levels hampering the binding of Co2+ to sites A and/or B. This is supported by biophysical studies and the co-association of a range of pathological conditions with positive ACB assays and high plasma FFA levels.

A diagnostic test accuracy meta-analysis of maternal serum ischemia-modified albumin for detection of preeclampsia

BACKGROUND/AIMS

Ischemia-modified albumin (IMA) has been widely accepted as a serological biomarker. IMA has been proposed as a simple and novel marker of oxidative stress in preeclampsia (PE). This systematic review and diagnostic test accuracy meta-analysis aims to evaluate the diagnostic accuracy of this novel serological biomarker, IMA to detect PE.

METHODS

A systematic search of major databases was performed to identify all published diagnostic accuracy studies on IMA. Risk of bias and applicability concerns were assessed for included studies. Summary estimates; the pooled sensitivity, specificity, and the diagnostic odds ratio (DOR) of IMA for the diagnosis of PE were computed using random-effects models. The overall test performance was summarized using summary receiver operating characteristic (SROC) curve analysis.

RESULTS

Six articles were included in this meta-analysis. The overall estimates of IMA in detecting PE were pooled sensitivity; 0.80 (95%CI 0.73-0.86), pooled specificity; 0.76 (95%CI 0.70-0.81), DOR; 14.32 (95%CI 5.06-40.57), and area under curve (AUC); 0.860. There was no between-study heterogeneity due to threshold effect.

CONCLUSIONS

This meta-analysis showed IMA could be useful as a biomarker for PE with good accuracy (AUC = 0.860). However, further research is needed for re-evaluation and clinical validation of fairly promising results of this meta-analysis.

Evaluation of maternal serum ischemia modified albumin and total antioxidant status in ectopic pregnancy

BACKGROUND

Ectopic pregnancies constitute about 2% of all pregnancies which are the leading cause of pregnancy-related deaths and a considerable cause of maternal morbidity. Oxidative stress can lead to a number of pregnancy related diseases including miscarriage, eclampsia and preterm labor. Ischemia modified albumin (IMA) which reflects the oxidative stress may be used as a marker for ectopic pregnancy. Our aim was to compare the levels of IMA and total antioxidant status (TAS) in ectopic and normal pregnancies and to understand if IMA can be used as a marker to diagnose ectopic pregnancy.

MATERIALS AND METHODS

Our case-control study consisted of 38 women with ectopic and 42 women with normal pregnancy. IMA and TAS levels were determined in serum samples with an albumin-cobalt binding test and by commercially available kits, respectively. IMA levels were adjusted according to serum albumin levels. Index of oxidation (IOS) was calculated by dividing adjusted IMA (A-IMA) levels with TAS. A receiver operating characteristics (ROC) curve analysis was made and cut-off values for the biomarkers were investigated in SPSS 21.0 program (SPSS, Chicago, IL). Data were presented as mean ± standard deviation and a p value < .05 was accepted as statistically significant.

RESULTS

There was a statistically significant difference in IMA, A-IMA, and IOS levels between ectopic and normal pregnancies. Although TAS level was not different statistically, it was lower in ectopic pregnancy. According to ROC curve analysis, IOS had the largest area under curve. A cut-off value of 0.545 for IOS had 81.6% sensitivity and 59.5% specificity.

CONCLUSIONS

According to our study, oxidative stress plays an important role in ectopic pregnancy and either A-IMA or IOS can be evaluated as a marker of ectopic pregnancy after further studies.

A meta-analysis of the association of serum ischaemia-modified albumin levels with human hypothyroidism and hyperthyroidism

Serum levels of ischaemia-modified albumin (IMA) have been studied as a novel and simple measure of oxidative stress (OXS) in different thyroid pathologies. However, results of available studies in the literature were not consistent. This meta-analysis was attempted to quantify the overall effect size for serum IMA levels in human hypothyroidism (HT) and hyperthyroidism (HYT) and to study its associations with the thyroid profile. Databases of PubMed/Medline, EMBASE, Google Scholar, Web of Science and Science Direct were searched for articles. Data on serum IMA levels in HT, HYT patients and euthyroid controls were extracted to compute standardized mean differences (SMD) by the random-effects model. The associations between IMA and thyroid profile were computed by the meta-analysis of correlation coefficients. IMA levels in HT patients (SMD=1.12; Z=2.76; P=0.006) and HYT patients (SMD=1.64; Z=2.57; P=0.01) were significantly higher than in euthyroid controls and the thyroid treatment showed a favourble effect on serum IMA levels. There were strong and significant correlations between IMA and hormonal status in HT and HYT groups. This meta-analysis showing increased IMA level in both HT and HYT patients and its association with thyroid profile suggests that serum IMA could be used as a simple measure of increased OXS in thyroid dysfunction.

The effect of L-thyroxine replacement therapy on ischemia-modified albümin and malondialdehyde levels in patients with overt and subclinical hypothyroidism

BACKGROUND AND OBJECTIVES

The main objective of this study was to evaluate the levels of ischemia-modified albumin (IMA) and malondialdehyde (MDA) in patients with subclinical (SHypo) and overt hypothyroidism (OHypo), and to assess the effects of levothyroxine (LT₄) therapy on the oxidative stress (OS) parameters. We also investigated the relationships among serum thyroid hormones, lipid parameters, and IMA and MDA in these patients.

DESIGN AND METHODS

Thirty untreated patients with OHypo, 25 untreated patients with Shypo, and 30 age- and sex-matched healthy controls were prospectively included in the study. Biochemical and hormonal parameters including IMA and MDA were evaluated in all patients just before and one month after the maintenance of euthyroidism.

RESULTS

Compared with the control subjects, the levels of MDA and triglycerides (TG) significantly increased in patients with SHypo (p < 0.001 and p < 0.05, respectively), whereas high density lipoprotein cholesterol (HDL-C) levels significantly decreased (p = 0.01). Patients with OHypo showed significantly high MDA, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), and TG levels (p = 0.001, p < 0.01, p = 0.01, and p < 0.01, respectively), and significantly low HDL-C levels compared with the controls (p < 0.05). MDA levels and lipid profile were not significantly different in the patients with OHypo when compared with the patients with SHypo. Serum IMA levels did not significantly change in patients with OHypo and SHypo compared with the controls. In the pre-treatment period, MDA levels were inversely correlated with HDL-C levels in patients with OHypo (r: -0.471, p = 0.009). Plasma MDA and LDL-C levels significantly decreased and HDL-C levels significantly increased in the groups of OHypo and SHypo after LT₄ treatment. Serum IMA levels did not significantly change with the therapy in all patient groups.

CONCLUSIONS

Increased MDA levels in both patient groups represent increased lipid peroxidation which might play an important role in the pathogenesis of the atherosclerosis seen in these patients. Increased OS in patients with SHypo and OHypo could be improved by LT₄ treatment. Also, MDA can be used as a reliable marker of OS and oxidative damage, while IMA is considered to be inappropriate.

Oxidative Stress and Advanced Glycation End Products in Hashimoto's Thyroiditis

BACKGROUND

Oxidative stress, which occurs as a result of an imbalance between free-radical production and antioxidant defense mechanisms, has been implicated in the pathogenesis of several autoimmune disorders, including thyroid diseases. Importantly, it has been correlated to thyroid dysfunction. This study investigated the changes in oxidative balance in euthyroid Hashimoto's thyroiditis (HT) by means of specific serum tests, such as derived reactive oxygen metabolites (d-ROMs) and the biological antioxidant potential (BAP) test. In addition, advanced glycation end products (AGEs) and advanced oxidation protein products (AOPPs)--compounds formed by the transformation of proteins--were evaluated as potential new markers of oxidative stress in this disease.

METHODS

This study included 134 euthyroid subject: 71 newly diagnosed HT patients (63 females; M age = 38 ± 13 years) and 63 age and sex-matched healthy controls. None of them were on thyroxine therapy.

RESULTS

Serum d-ROMs were elevated, and BAP decreased in HT patients compared with controls (p < 0.001), and the two parameters were inversely correlated (r = -0.211; p = 0.027), clearly indicating an enhanced oxidative stress. Furthermore, AGE levels were higher in HT patients (M = 223.18 AU/g prot) than in controls (M = 189.636 AU/g prot; p = 0.020) and inversely correlated with BAP levels (r = -0.196; p = 0.037). In uni- and multivariate analysis, serum antithyroperoxidase antibodies were the main predictors for d-ROMs (p = 0.006), BAP (p < 0.001), and AGEs (p = 0.014), irrespective of thyrotropin and/or free thyroxine values. No differences in AOPPs levels were found between patients and controls (p = 0.923).

CONCLUSIONS

Oxidants are increased and antioxidants decreased in euthyroid HT patients. As a result, the oxidative/antioxidative balance is shifted toward the oxidative side. Moreover, this study reports on a possible significant involvement of AGEs in HT, thus contributing to a better definition of the redox homoeostasis dysregulation in HT.