The significance of thiol/disulfide homeostasis and ischemia-modified albumin levels to assess the oxidative stress in patients with different stages of diabetes mellitus

Oxidant and antioxidant balance in children with bacteremia

BACKGROUND

There is a crucial balance between oxidant and antioxidant defense mechanisms. We aimed to evaluate the role of the balance of these systems in children with bloodstream infection.

METHODS

We analyzed prospectively oxidant and antioxidant stress parameters from serum samples of children with BSI besides demographic and clinical data of children. Serum levels of the total antioxidant status (TAS), total oxidant status (TOS), albumin, plasma thiol, disulphide, catalase (CAT), myeloperoxidase (MPO), ischemia-modified albumin (IMA) levels, ferroxidase and arylesterase (ARES) activity were evaluated in both patients and healthy controls.

RESULTS

A total of 113 children were evaluated, 50 of them had bacteremia and the remaining 63 were healthy subjects. The median TOS values were 18.5 µmol H2O2/L and 13.1 µmol H2O2/L in patient and control groups, respectively with a statistically significant difference between groups. The mean serum IMA levels were 0.8±0.1 absorbance unit (ABSU) in patients and 0.5±0.09 ABSU in control, the difference between groups was statistically significant. The native thiol, total thiol levels and the disulphide levels were significantly lower in the patient group as compared with the control group. The myeloperoxidase level was 136 U/L in patients and 107 in controls with a statistically significant difference between groups.

CONCLUSIONS

TOS, IMA, MPO, and particularly plasma thiols seem good candidates for accurate diagnosis of bacteremia in children.

Diagnostic values of ischemia modified albumin in diabetes-related complications: a narrative review

Purpose

Oxidative stress (OS) plays a critical role in the onset and progression of macro and microvascular complications of diabetes mellitus (DM). Ischemia-modified albumin (IMA) is a novel and simple test for evaluating OS. In the present study, we reviewed the available information on the alteration of circulating IMA in DM and its possible prognostic and diagnostic value in DM-related complications.

Methods

Relevant studies regarding IMA alteration in DM published until May 30, 2022 were extracted from Google Scholar, PubMed, Scopus, and Science Direct databases. The following key words were used: IMA, DM, diabetes complications, retinopathy, nephropathy, diabetic foot, and vascular complications.

Results

This review revealed increased circulating IMA levels in the patients with type 1, type 2, and gestational DM. Furthermore, IMA showed a close relationship with the severity of DM complications including hyperglycemia, dyslipidemia, diabetic retinopathy, diabetic nephropathy, peripheral arterial disease, and diabetic foot ulcer. However, lack of assay standardization and low specificity are major obstacles to the use of IMA as a promising biomarker.

Conclusion

IMA levels are associated with DM complications and can be applied as a practical test for evaluating the risk and predicting the severity of DM complications.

Evaluation of the effects of empagliflozin on acute lung injury in rat intestinal ischemia-reperfusion model

BACKGROUND

Empagliflozin is a selective sodium-glucose co-transporter (SGLT2) inhibitor that is approved for the treatment of type 2 diabetes. The beneficial effects of empagliflozin on other organ systems including the heart and kidneys have been proven. The aim of this study is to evaluate the role of empagliflozin on acute lung injury induced by intestinal ischemia-reperfusion (I/R).

MATERIALS AND METHODS

A total of 27 male Wistar albino rats were divided into three groups: sham, I/R, and I/R + empagliflozin; each group containing nine animals. Sham group rats underwent laparotomy without I/R injury. Rats in the I/R group underwent laparotomy, 1 h of after ischemia-reperfusion injury (superior mesenteric artery ligation was followed by 2 h of reperfusion). Rats in I/R were given empagliflozin (30 mg/kg) by gastric gavage for 7 days before the ischemia-reperfusion injury. All animals were killed at the end of reperfusion and lung tissue samples were obtained for immunohistochemical staining and histopathological investigation in all groups.

RESULTS

Serum glucose, AST, ALT, creatinine, native thiol, total thiol, and disulfide levels and disulfide-native thiol, disulfide-total thiol, and native thiol-total thiol ratios as well as the IMA levels were analyzed and compared among the groups. While intestinal I/R significantly increases serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatinine levels; did not cause any change in homeostasis parameters and IMA level. Empagliflozin treatment had no significant effect on biochemical parameters. Empagliflozin treatment induced a significant decrease in positive immunostaining for IL-1, IL-6, TNF-alpha, caspase 3, caspase 8, and caspase 9 compared to the I/R group in lung tissue samples. Intestinal I/R caused severe histopathological injury including edema, hemorrhage, increased thickness of the alveolar wall, and infiltration of inflammatory cells into alveolar spaces. Empagliflozin treatment significantly attenuated the severity of intestinal I/R injury.

CONCLUSIONS

It was concluded that empagliflozin treatment may have beneficial effects in acute lung injury, and, therefore, has the potential for clinical use.

Dynamic thiol-disulphide homeostasis as a biomarker for predicting the development of contrast medium-associated acute kidney injury in the endovascular treatment of peripheral arterial disease: should intravenous N-acetylcysteine be given before the procedure?

AIM

To determine the predictive ability of serum thiol-disulphide levels for contrast medium-associated acute kidney injury (CA-AKI) after endovascular treatment (EVT) of peripheral arterial disease (PAD) and evaluate the efficacy of intravenous N-acetylcysteine (NAC) in preventing CA-AKI.

MATERIAL AND METHODS

This double-blind, randomised controlled study included 85 consecutive adult patients who underwent EVT for PAD. Patients were divided into NAC negative (NAC-) and positive (NAC+) groups. While the NAC- group received only 500 ml saline, the NAC + group received 500 ml saline plus intravenous 600 mg NAC before the procedure. Intra- and intergroup patient characteristics, procedural details, preoperative thiol-disulphide levels, and ischaemia-modified albumin (IMA) levels were recorded.

RESULTS

There was a significant difference between NAC- and NAC + groups regarding native thiol, total thiol, disulphide/native thiol ratio (D/NT), and disulphide/total thiol ratio (D/TT). There was also a significant difference between the NAC- (33.3%) and NAC+ (13%) groups in CA-AKI development. Logistic regression analysis showed that the D/TT (OR 2.463) and D/NT (OR 2.121) were the most influential parameters for CA-AKI development. In the receiver operating characteristic (ROC) curve analysis, the sensitivity of native thiol to detect the development of CA-AKI was 89.1%. The negative predictive values of native thiol and total thiol were 95.6% and 94.1%, respectively.

CONCLUSION

The serum thiol-disulphide level can be used as a biomarker to detect CA-AKI development and reveal patients with a low risk for CA-AKI development before EVT of PAD. Furthermore, thiol-disulphide levels allow for the indirect quantitative monitoring of NAC. Preprocedural intravenous NAC administration significantly inhibits CA-AKI development.

Value of thiol and ischemia modified albumin (IMA) in predicting mortality in serious COVID-19 pneumonia

Background/aim

Viral infections of the respiratory tract are generally related to many factors such as excessive production of cytokines, inflammation, cellular death, redox imbalance or oxidative stress. The aim of this study was to determine the serum levels of thiol and IMA in patients with severe COVID-19 pneumonia to evaluate oxidative stress.

Study design

This was a prospective, sectional cohort study conducted at a pandemics hospital between 01.01.2022 and 01.02.2022.

Methods

A total of 153 patients who had been confirmed with severe COVID-19 pneumonia in the emergency unit were prospectively analyzed. The control group was formed by 50 healthy volunteers with similar age and no chronic disease history. Thiol and IMA levels were statistically compared both in the patient and the control groups, and within the patient groups (survived and non-survival).

Results

While 96 out of 153 patients had survived, 57 patients had non-survival. There was a statistically significant distinction between the survived and non-survival patients with regard to Thiol and IMA levels (p < 0.001). The thiol levels in the patient group were significantly lower compared to the control group, and the IMA levels were significantly higher (p < 0.001). The sensitivity, specificity and NPV were 70.2%, 86.5% and 83% when thiol cut-off value was ≤345.2 μmol/L (AUC: 0.886, p < 0.001). The sensitivity, specificity and NPV were 70.2%, 85.4% and 82.8% when the IMA cut-off was >302.9 ABSU (AUC: 0.875, p < 0.001).

Conclusions

Our results demonstrate that thiol and IMA levels may be used as bioindicators for risk classification and mortality in patients with serious COVID-19 pneumonia.

Evaluation of Fetal Serum Thiol/Disulfide Homeostasis and Ischemia-Modified Albumin Levels in Fetal Distress

Aim: We investigated the association of fetal serum thiol/disulfide homeostasis and ischemia-modified albumin (IMA) levels with fetal distress (FD). Methods: Umbilical cord blood for native thiol, total thiol, disulfide, albumin, and IMA analysis was obtained from 44 pregnant women over 34 weeks gestation undergoing cesarean section due to non-acute FD, and from 61 healthy pregnant women who underwent elective cesarean section Results: Native thiol and total thiol levels were significantly lower in the FD group (p = 0.02 and p = 0.014, respectively). Although disulfide/native thiol and disulfide/total thiol ratios were higher in the FD group, the difference was statistically insignificant (p = 0.805). The IMA levels were significantly higher in the FD group (p = 0.013). Conclusion: The thiol-disulfide homeostasis shifts toward the oxidant direction during the FD pathogenesis and the increased IMA levels may be the best indicator of an underlying non-acute ischemic condition.

Fructose and methylglyoxal-induced glycation alters structural and functional properties of salivary proteins, albumin and lysozyme

Glycation process refers to reactions between reduction sugars and amino acids that can lead to formation of advanced glycation end products (AGEs) which are related to changes in chemical and functional properties of biological structures that accumulate during aging and diseases. The aim of this study was to perform and analyze in vitro glycation by fructose and methylglyoxal (MGO) using salivary fluid, albumin, lysozyme, and salivary α-amylase (sAA). Glycation effect was analyzed by biochemical and spectroscopic methods. The results were obtained by fluorescence analysis, infrared spectroscopy (total attenuated reflection-Fourier transform, ATR-FTIR) followed by multivariate analysis of principal components (PCA), protein profile, immunodetection, enzymatic activity and oxidative damage to proteins. Fluorescence increased in all glycated samples, except in saliva with fructose. The ATR-FTIR spectra and PCA analysis showed structural changes related to the vibrational mode of glycation of albumin, lysozyme, and salivary proteins. Glycation increased the relative molecular mass (Mr) in protein profile of albumin and lysozyme. Saliva showed a decrease in band intensity when glycated. The analysis of sAA immunoblotting indicated a relative reduction in intensity of its correspondent Mr after sAA glycation; and a decrease in its enzymatic activity was observed. Carbonylation levels increased in all glycated samples, except for saliva with fructose. Thiol content decreased only for glycated lysozyme and saliva with MGO. Therefore, glycation of salivary fluid and sAA may have the potential to identify products derived by glycation process. This opens perspectives for further studies on the use of saliva, an easy and non-invasive collection fluid, to monitor glycated proteins in the aging process and evolution of diseases.

The role of protein oxidation in the development of diabetic microvascular complications

OBJECTIVE

The role of protein oxidation in the development of diabetic microvascular complications was investigated.

METHODS

In total, 266 participants were split into five groups: Group 1; diabetes mellitus for at least 10 years without any complications, Group 2; diabetic nephropathy, Group 3; diabetic neuropathy, Group 4; diabetic retinopathy, and Group 5; control group. Thiol, disulfide, ferroxidase, and ischemia-modified albumin (IMA) levels were analyzed in the serum.

RESULTS

Native thiol, total thiol, and native thiol/total thiol were lower in Group 4 than Groups 1, 3, and 5 (p<0.001). However, disulfide/native thiol and disulfide/total thiol were higher in Group 4 than all other groups (p<0.001). IMA was higher in Groups 3 and 4 than all other groups (p<0.001). Ferroxidase was lower in Groups 3 and 4 than Group 2 (p<0.001).

CONCLUSION

Thiol-disulfide homeostasis impairment in favor of disulfide may have a function in the progress of diabetic retinopathy. Furthermore, the disruptions of IMA and ferroxidase levels involve in the development of diabetic retinopathy and neuropathy.

Can thiol-disulfide balance be an indicator of oxidative stress for hyperhidrosis?

BACKGROUND

Hyperhidrosis is responsible for various causes. The increased reactive oxygen radical production with insufficient antioxidant mechanism capacity may play a role in the etiopathogenesis of hyperhidrosis. It is probable to gather data about oxidative stress by detecting plasma thiol/disulfide ratio. The aim of this study was to determine whether thiol-disulfide balance changes in patients with hyperhidrosis.

METHODS

The files of patients who were diagnosed with hyperhidrosis in the dermatology outpatient clinic between 2015 and 2018 and whose native thiol, total thiol, and disulfide values were examined for any reason were examined.

RESULTS

Seventy-three patients were included in the study. 33 of the patients with hyperhidrosis were primary. Mean age; for primary hyperhidrosis patients (PHH) = 26.36 ± 7.61, primary hyperhidrosis (PHH) control group = 27.16 ± 7.94; secondary hyperhidrosis (SHH) patients = 47.88 ± 12.29, SHH control (45.40 ± 12.02). The native thiol values of PHH (469.93 ± 56.82 μmol/L) were higher than SHH (440.64 ± 62.72) (p = 0.024). However, as a result of thiol-disulfide comparison between hyperhidrosis patients (PHH and SHH) and control groups, disulfide levels increased (p = 0.04). In the PHH group, total thiol was measured as 512 ± 54.84 μmol/L, and SHH was measured as 484.11 ± 58.9 μmol/L, (p = 0.074).

CONCLUSION

Serum thiol levels in SHH increased more than PHH. As a result of thiol-disulfide comparison between hyperhidrosis patients and control groups, the balance shifted in favor of disulfide and oxidative side.

Prognostic value of thiol/disulfide homeostasis in symptomatic patients with heart failure

We aimed to examine the role of thiol/disulphide homeostasis (TDH) in heart failure and its stages and the prognosis of heart failure. A total of 140 subjects were included in the study. Total and native thiol levels were higher in the control group compared to the patient groups (p < .001). While the average disulphide/total thiol ratio was similar in groups 1 and 2, it was found to be significantly lower in the control group compared to other groups and significantly higher in group 3 compared to other groups (p < .05). Mean native thiol and total thiol levels were found lower in patients with mortality compared to surviving patients (p < .001). In ROC curve analysis, it was determined that the total thiol level had 81.8% sensitivity and 83.1% specificity, and native thiol level had 81.8% sensitivity and 84.3% specificity. We found that TDH was impaired in favour of disulphide in cases of heart failure.

Oxidant and antioxidant balance in patients with COVID-19

BACKGROUND

A crucial balance exists between oxidant and antioxidant mechanisms in the functional immune system. We aimed to evaluate the contributions of balance between these systems to coronavirus disease 2019 (COVID-19), a devastating pandemic caused by viral infection.

METHOD

We analyzed serum oxidant and antioxidant stress parameters according to the clinical and demographic characteristics of children and adults with COVID-19 and compared them against the values of healthy controls. Serum native thiol (NT), total thiol (TT), disulfide, total antioxidant status, total oxidant status, and ischemia-modified albumin levels were evaluated and compared between groups.

RESULTS

A total of 79 children and 74 adults were evaluated in the present study, including 46 children and 40 adults with COVID-19, 33 healthy children, and 34 healthy adults. TT, NT, and disulfide levels were significantly lower in the adult COVID-19 group than in all other groups (p = .001, p = .001, and p = .005, respectively). Additionally, TT and NT levels were significantly lower in both pediatric and adult COVID-19 cases with severe disease course than mild/moderate course. TT and NT levels were identified as predictors for the diagnosis of the adult COVID-19 cases and as independent predictors for disease severity in both children and adults with COVID-19.

CONCLUSION

Parameters that reveal the oxidant and antioxidant capacity, including TT and NT, appear to be good candidates for the accurate prediction of the clinical course among patients with COVID-19.

Oxidant and Antioxidant Balance in Children with Community-Acquired Pneumonia

Objective The balance between oxidant and antioxidant defense mechanisms is crucial. In this article, we aimed to evaluate the role of this balance in community-acquired pneumonia (CAP) in children.

Methods We analyzed serum oxidant and antioxidant stress parameters according to the clinical and demographic data of children with CAP and compared them with healthy controls. Serum total antioxidant status (TAS) and total oxidant status (TOS) were evaluated and compared between the groups, along with levels of ischemia-modified albumin (IMA), antioxidant enzymes, nonenzymatic antioxidant factors, and plasma thiol.

Results Of 160 children evaluated, 106 had CAP (54 outpatients and 52 inpatients), and the other 54 were healthy (control group). Total thiol and native thiol levels were significantly lower in the inpatient group compared with the outpatient group (p = 0.004 and p = 0.005, respectively). Serum IMA differed significantly among the groups (p = 0.001), with inpatients showing the highest level. A positive correlation was found between serum IMA and C-reactive protein levels in patients with pneumonia (r = 0.351; p = 0.001).

Conclusion Parameters that provide information about antioxidant capacity may be useful in the diagnosis and prognosis of pneumonia. Our results suggest that plasma thiol levels and IMA may be good candidate biomarkers to predict hospitalization for CAP in children.

Association between Plasma Thiol Parameters and Troponin Levels in Patients with Acute Coronary Syndrome and Prediction of In-Hospital Ventricular Arrhythmia

Fundamento

As arritmias ventriculares (AVs) são a principal causa de mortalidade e morbidade hospitalar em pacientes com síndrome coronariana aguda (SCA) e sua relação com o tiol é desconhecida.

Objetivo

Investigar a relação entre os níveis plasmáticos de tióis e os níveis de troponina em pacientes com SCA e estimar o desenvolvimento de AV intra-hospitalar durante a internação.

Método

O estudo incluiu 231 pacientes consecutivos com SCA com supradesnivelamento do segmento ST (SCA-SDST) e pacientes com SCA sem supradesnivelamento do segmento ST (SCA-SSDST). Após a aplicação dos critérios de exclusão, 191 pacientes foram incluídos na análise estatística. Os pacientes foram classificados em dois grupos: grupo SCA-SDST (n=94) e grupo SCA-SSDST (n=97). Os níveis plasmáticos de tiol, dissulfeto e troponina foram medidos e a razão de troponina para tiol nativo (RTTN) foi calculada. Considerou-se estatisticamente significativo um valor de p bilateral inferior a 0,05.

Resultados

Tiol nativo plasmático, tiol total, dissulfeto e suas razões foram semelhantes entre os grupos. A RTTN se mostrou significativamente maior no grupo SCA-SDST em comparação com o grupo SCA-SSDST. Houve correlação negativa significativa entre os níveis de troponina e tiol. Verificou-se que o tiol nativo é preditor independente do desenvolvimento de AV em pacientes com SCA-SDST e em todos os pacientes com SCA. Verificou-se que o RTTN é preditor independente do desenvolvimento de AV em pacientes com SCA-SSDST e em todos os pacientes com SCA.

Conclusão

Os níveis plasmáticos de tiol podem ser usados para identificar pacientes com alto risco de desenvolvimento de AV intra-hospitalar em pacientes com SCA. A correlação entre os níveis de troponina e tiol pode sugerir que os tióis possam ser marcadores importantes para o diagnóstico e prognóstico da SCA com a ajuda de estudos futuros.

Thiol-disulphide balance and total oxidant-antioxidant status in patients with chronic hepatitis C

OBJECTIVE

To assess the dynamic thiol/disulphide homeostasis (DTDH) and total oxidant/antioxidant status in patients with hepatitis C virus (HCV) infection and to evaluate their association with HCV-RNA levels.

METHODS

Levels of serum total thiol (TT), native thiol (NT), disulphide (DS), total oxidant status (TOS), total antioxidant status (TAS) and oxidative stress index (OSI) as oxidative stress markers were determined in 162 individuals, including 74 patients with HCV infection and 88 non-HCV controls. HCV genotypes and HCV-RNA levels of the patients were recorded.

RESULTS

The NT, TT and TAS levels and NT/TT ratio were significantly lower in the HCV group compared with the control group. On the contrary, DS, TOS and OSI levels and DS/NT and DS/TT ratios were significantly higher. Patients with high HCV RNA levels (> 650 000 IU/mL) had higher DS levels than patients with low HCV-RNA levels (<650 000 IU/mL). Genotype 1 was observed in 68.9% of patients with HCV. Levels of oxidative stress parameters were similar between genotype 1 and other genotypes (2, 3 and 5). No significant correlations were found between oxidative stress markers and albumin, alanine aminotransferase, aspartate aminotransferase, bilirubin and HCV-RNA levels in patients with HCV infection. A negative correlation was found only between OSI and albumin.

CONCLUSION

Our results suggest that DTDH shifts towards the DS direction because of thiol oxidation in HCV-infected patients. Furthermore, DS levels were significantly higher in patients with high HCV-RNA levels compared with patients with low HCV-RNA levels.

Impaired thiol/disulphide homoeostasis in children with steroid-sensitive nephrotic syndrome

BACKGROUND

Abnormal thiol/disulphide homoeostasis (TDH) is responsible for the pathogenesis of various diseases. We aimed to examine the TDH in children with steroid-sensitive nephrotic syndrome (SSNS).

METHODS

A total of 131 children, 60 with SSNS and 71 healthy controls, participated in the study. Plasma total thiol (TT), native thiol (SH) and disulphide (SS) levels in the SSNS during remission and control groups were estimated using a new method developed by Erel and Neselioglu.

RESULTS

Albumin, TT, SH levels and SH/TT ratio were decreased, whereas SS/SH and SS/TT ratios were elevated in SSNS group compared with control group. However, there was no significant difference in SS levels between the two groups. Albumin level was positively correlated with TT, SH and SS levels in the SSNS group.

CONCLUSIONS

We found that TDH shifts in favour of oxidants in children with SSNS in remission. This shift indicates that SSNS patients are exposed to augmented oxidative stress.

Oxidative-Antioxidative Markers in Pregnant Women with Fetal Neural Tube Defects

We compared markers of oxidative stress (OS) in mothers with and without fetal neural tube defects (NTDs). Methods: Pregnant mothers in the second trimester with NTD-affected fetuses and age, gestational age, and body mass index-matched control mothers with unaffected fetuses were included. Maternal serum thiol-disulfide homeostasis parameters and ischemia-modified albumin (IMA) were measured. Results: In 30 affected mothers compared to 31 controls, disulfide levels, disulfide/native thiol, and disulfide/total thiol ratios were higher; native and total thiol levels and native thiol/total thiol ratios were lower (p < 0.001). Mothers with NTD-affected fetuses had higher levels of IMA than controls (p = 0.025). Conclusion: The thiol-disulfide homeostasis balance was shifted in favor of disulfide, suggesting increased thiol oxidation and OS in the second trimester of NTD-affected pregnancies. Maternal levels of IMA, an oxidatively altered form of albumin, thus a measure of OS, were higher in NTD-affected second trimester pregnancies compared to controls.

The Relationship between Choroidal Thickness and Intracellular Oxidised-reduced Glutathione and Extracellular Thiol-disulfide Homeostasis at Different Stages of Diabetic Retinopathy

Purpose: To evaluate the relationship between diabetic retinopathy and oxidative damage by measuring intracellular and extracellular thiol levels, and to compare intracellular and extracellular thiol levels. Method: In this prospective, cross-sectional, and comparative study, 25 healthy control participants (group 1), a total of 25 diabetic macular edema (DME) patients with non-proliferative diabetic retinopathy (DRP) and without DME (group 2), and 25 DME patients with non-proliferative DRP and with DME (group 3) were included. Choroidal thickness (ChT) and central macular thickness (CMT) were measured by spectral domain optic coherence tomography. For the evaluation of antioxidant/oxidant balance, intracellular GSH (reduced glutathione) and GSSG (oxidized glutathione), extracellular SH (thiol) and SS (disulfide) levels were measured and recorded. Results: Comparing intracellular and extracellular thiol levels between groups, intracellular GSSG level and GSSG/GSH percent ratio, and extracellular disulfide and SS/SH percent ratio values were higher in diabetic patients than healthy participants. Choroidal thicknesses were significantly thinner in DRP groups compared to the healthy population. When the relationship between choroidal thicknesses and thiol levels was investigated, there were significant relationships between choroidal thicknesses and thiol levels in group 3. Conclusion: Oxidative stress and impaired intracellular GSH/GSSG and serum SH/SS balances were observed to have an effect on DRP and DME pathogenesis. In addition, in groups with and without DME, thinning in choroidal thicknesses and the relationship between these thicknesses and intra/extracellular oxidative stress indicators can also be explained.

Thiol-disulfide homeostasis: an integrated approach with biochemical and clinical aspects

Dynamic thiol-disulfide homeostasis (TDH) is a new area has begun to attract more scrutiny. Dynamic TDH is reversal of thiol oxidation in proteins and represents the status of thiols (-SH) and disulfides (-S-S-). Organic compounds containing the sulfhydryl group is called thiol, composed of sulfur and hydrogen atoms. Disulfides are the most important class of dynamic, redox responsive covalent bonds build in between two thiol groups. For many years, thiol levels were analyzed by several methods. During last years, measurements of disulfide levels have been analyzed by a novel automated method, developed by Erel and Neselioglu. In this method, addition to thiol (termed as native thiol) levels, disulfide levels were also measured and sum of native thiol and disulfide levels were termed as total thiol. Therefore, TDH was begun to be understood in organism. In healthy humans, TDH is maintained within a certain range. Dysregulated dynamic TDH has been implicated several disorders with unknown etiology. A growing body of evidence has demonstrated that the thiol-disulfide homeostasis is involved in variety diseases, such as diabetes mellitus, hypertension, nonsmall cell lung cancer, familial Mediterranean fever (FMF), inflammatory bowel diseases, occupational diseases, gestational diabetes mellitus and preeclampsia. These results may elucidate some pathogenic mechanism or may be a predictor indicating diagnostic clue, prognostic marker or therapeutic sign. In conclusion, protection of the thiol-disulfide homeostasis is of great importance for the human being. Evidence achieved so far has proposed that thiol-disulfide homeostasis is an important issue needs to elucidate wholly.

Ischemia-Modified Albumin Levels and Thiol-Disulphide Homeostasis in Diabetic Macular Edema in Patients with Diabetes Mellitus Type 2

PURPOSE

It was aimed to assess the role of thiol-disulphide homeostasis and ischemia-modified albumin (IMA) level in the development of diabetic macular edema (DME) in patients with diabetes mellitus type 2 (T2DM).

MATERIALS AND METHODS

Sixty-six study patients were divided into two groups. Group I included 43 patients with T2DM and DME, and Group 2 included 23 patients with T2DM without eye involvement. A novel colorimetric method was used to assess thiol-disulphide homeostasis. Between the two groups IMA, total anti-oxidant, and total oxidant levels were measured and compared.

RESULTS

In Group 1, total and native thiol levels and disulphide levels were lower compared to Group 2 (p = .025, p < .001 and p = .013, respectively). Disulphide/native thiol, disulphide/total thiol ratios and native thiol/total thiol were similar between the groups. Total anti-oxidant level (TAL) reduced whereas total oxidant level (TOL) increased in Group 1 compared to Group 2 (p = .001, p = .002, respectively). Albumin level decreased, whereas IMA level increased in Group 1 compared to Group 2 (p < .001 for both).

CONCLUSIONS

The disruption in thiol/disulphide homeostasis, increased IMA and oxidative stress have an impact on the development of diabetic macular edema.

Dynamic thiol/disulphide homeostasis metrics as a risk factor for peripheral arterial disease

OBJECTIVE

To examine dynamic thiol/disulphide homeostasis metrics as a novel risk factor of oxidative stress in patients with peripheral arterial disease.

METHODS

One hundred patients with lower extremity peripheral arterial disease (a study group) and 100 control subjects were included in this prospective case-control study. Participants' baseline clinical characteristics and laboratory data including some oxidant/antioxidant status parameters such as albumin, ferroxidase and myeloperoxidase, and thiol/disulphide homeostasis parameters such as native thiol, total thiol and disulphide, as well as native thiol/total thiol, disulphide/native thiol and disulphide/total thiol ratios were all recorded and then compared between the groups.

RESULTS

Mean albumin and ferroxidase, and median myeloperoxidase levels were found to be significantly higher in patients with the peripheral arterial disease than in control group (p = 0.045, p = 0.000 and p = 0.000, respectively). Mean native thiol and total thiol, and median disulphide levels were found to be significantly lower in the study group as compared with the control group (p = 0.000, p = 0.000 and p = 0.037, respectively). According to the results of logistic regression analysis, systolic blood pressure, ferroxidase and myeloperoxidase levels were detected to be the independent predictors of peripheral arterial disease.

CONCLUSION

Our report is the first one in the literature investigating dynamic thiol/disulphide homeostasis metrics as a novel risk factor of oxidative stress in peripheral arterial disease. Dynamic thiol/disulphide homeostasis metrics may be used as a valuable risk factor of oxidative stress in patients with the peripheral arterial disease since it is readily available, easily calculated and relatively cheap.

The role of oxidative stress on subclinical atherosclerosis in premature ovarian insufficiency and relationship with carotid intima-media thickness

Objective: We aimed to investigate the relationship between oxidative stress (OS) and subclinical atherosclerosis in patients with premature ovarian insufficiency (POI), by analyzing the dynamic thiol/disulfide homeostasis (TDH) parameters as an OS marker and carotid intima-media thickness (CIMT).Materials and methods: A total of 69 women, 34 with POI and 35 healthy controls were included in this prospective cross-sectional study. TDH parameters (plasma native thiol, total thiol, disulfide, disulfide/native thiol, native thiol/total thiol, and disulfide/total thiol ratios) and CIMT were measured and compared between the two groups.Results: In primary ovarian insufficiency group, native thiol (p=.009) and total thiol (p=.010) levels were significantly decreased, and CIMT values were significantly increased (p= <.001). CIMT values were negatively correlated with native thiol (r=-0.553, p=.001) and total thiol levels (r=-0.565, p=.001); and positively correlated with age (r = 0.457, p=.007), BMI (r = 0.408, p=.017), and total cholesterol (r = 0.605, p<.001) in POI group.Conclusions: Decreased native thiol and total thiol levels demonstrate the defective anti-oxidant mechanism in POI. Negative correlation between native thiol, total thiol levels, and CIMT means the presence of abnormal anti-oxidant mechanisms may play a role in the development of subclinical atherosclerosis in patients with POI. This is a novel report on the mechanism of subclinical atherosclerosis in women with POI, which needs to be supported with further studies evaluating the pathophysiology of OS.

Relationship between diabetic polyneuropathy, serum visfatin, and oxidative stress biomarkers

BACKGROUND

Diabetic polyneuropathy is a very common complication of diabetes. Numerous studies are available in terms of pathogenesis. But examination methods with low reliability are still not standardized and generally time consuming. High-sensitive, easy-to-access methods are expected. Biochemical markers are one of the subjects of research. We aimed to discover a potential biomarker that can be used for this purpose in patients with diabetes who have not yet developed symptoms of neuropathy.

AIM

To determine the place and availability of visfatin and thiol-disulfide homeostasis in this disorder.

METHODS

A total of 392 patients with type 2 diabetes mellitus were included in the study. The polyneuropathy clinical signs were evaluated with the Subjective Peripheral Neuropathy Screen Questionnaire and Michigan Neuropathy Screening Instrument questionnaire and examination. The biochemical parameters, oxidative stress markers, visfatin, and thiol-disulfide homeostasis were analyzed and correlated with each other and clinical signs.

RESULTS

Subjective Peripheral Neuropathy Screen Questionnaire and Michigan Neuropathy Screening Instrument questionnaire with examination scores were correlated with each other and diabetes duration (P < 0.005). Neuropathy related symptoms were present in 20.7% of the patients, but neuropathy related findings were observed in 43.9% of the patients. Serum glucose, glycated hemoglobin, and visfatin were positively correlated with each other. Also, these parameters were positively correlated with the total oxidative stress index. Total and native thiol was positively correlated with total antioxidant status and negatively with oxidant status. Inversely thiol-disulfide positively correlated with higher glucose and oxidant status and negatively with total antioxidant status (P < 0.005). There was no correlation between visfatin and thiol-disulphide (P = 0.092, r = 0.086). However, a significant negative correlation was observed between visfatin and total with native thiol (P < 0.005, r = -0.338), (P < 0.005, r = -0.448).

CONCLUSION

Diagnosis of neuropathy is one of the issues studied in patients with diabetes. Visfatin and thiol-disulfide balance were analyzed for the first time in this study with inspiring results.

Thiol/disulfide homeostasis in patients with ocular-active and ocular-inactive Behçet disease

PURPOSE

To evaluate thiol/disulfide homeostasis in ocular-active (OA) and ocular-inactive (OI) Behçet disease (BD) patients and compare the data with healthy subjects.

METHODS

Twenty OABD patients, 20 OIBD patients and 20 healthy control subjects were included into the study. The BD ocular attack score 24 (BOS24) scoring system was used to assess the activity of disease in ocular BD patients. Systemic activity was also evaluated using BD current activity form (BDCAF). The native thiol (NT), total thiol (TT) and disulfide levels and NT/TT, disulfide/NT and disulfide/TT ratios were measured via using an innovative and automated method.

RESULTS

BOS24 and BDCAF scores were 13.25 ± 2.32 and 4.18 ± 2.06 in OABD patients and 0.31 ± 0.47 and 2.14 ± 1.98 in OIBD patients, respectively. The NT, TT levels and NT/TT ratio were significantly reduced; in contrast, the disulfide levels, disulfide/NT and disulfide/TT ratios were significantly increased in OABD and OIBD patients compared to the healthy control subjects (p < 0.05). Moreover, while the levels of NT and TT were significantly reduced, the disulfide levels as well as disulfide/NT and disulfide/TT ratios were significantly elevated between OABD and OIBD patients (p < 0.05). However, the ratio of NT/TT did not significantly differ between OABD and OIBD patients (p = 0.449). The multiple regression model including BOS24 and BDCAF score statistically significantly predicted NT level, TT level and disulfide level (p < 0.001 for all).

CONCLUSION

Thiol oxidation in BD patients resulted in a change of the thiol/disulfide balance. Therefore, thiol/disulfide homeostasis in BD patients can be used an innovative oxidative stress marker.

Factors associated with oxidative stress status in pediatric patients with type 1 diabetes mellitus

Background Oxidative stress is implicated in both, the onset and the progression of type 1 diabetes mellitus (T1DM). There is accumulated evidence of increased biomarkers of oxidative stress in newly diagnosed, T1DM patients without complications, and in those with advanced disease. In this cross-sectional study, we investigated factors affecting oxidative stress status in pediatric patients with T1DM. Methods Advanced oxidation protein products (AOPP), prooxidant-antioxidant balance (PAB), total sulfhydryl (SH) groups, and superoxide dismutase (SOD) activity were determined in 170 children and adolescents with T1DM. Principal component analysis was used to investigate clustering of clinical and laboratory variables associated with elevated oxidative stress and reduced antioxidative defense biomarkers. Results Factor analysis extracted five factors, interpreted as (1) "weight status factor" including age, BMI, waist and hip circumferences; (2) "proatherogenic factor" that included LDL-cholesterol, non-HDL-cholesterol, and triglycerides; (3) "metabolic control factor" including glucose and HbA1c; (4) "renal marker factor" with positive loading of urinary albumin excretion rate and negative loading of GFR; and (5) "antiatherogenic factor" that included HDL-cholesterol. High AOPP levels were independently predicted by "proatherogenic" (OR: 2.32; 95% CI: 1.44-3.71; p < 0.001), "metabolic control" (OR: 2.24; 95% CI: 1.35-3.73; p < 0.01), and "renal marker" (OR: 1.65; 95% CI: 1.03-2.65; p < 0.05) factors. "Renal marker factor" was a significant predictor of PAB (OR: 0.52; 95% CI: 0.34-0.81; p < 0.01). Regarding antioxidative defense markers, reduced SH groups were predicted by "proatherogenic factor" (OR: 0.56; 95% CI: 0.34-0.94; p < 0.05), while "weight status factor" predicted lower SOD activity (OR: 1.66; 95% CI: 1.03-2.67; p < 0.05). Conclusions Cardiometabolic risk factors and renal function are associated with oxidative stress in pediatric T1DM patients.

Extraction of Phenolic Compounds from Tabernaemontana catharinensis Leaves and Their Effect on Oxidative Stress Markers in Diabetic Rats

The aim of this study was to evaluate the most effective extraction condition (temperature, solvent type and time) for recovery of high-value phytochemicals present in the Tabernaemontana catharinensis leaves (TC) and to assess their effect on biochemical parameters in streptozotocin-induced diabetic rats. The extraction of phenolic compounds from TC using a factorial design (FD) 2³, high performance liquid chromatography (HPLC), response surface methodology (RSM) and principal component analysis (PCA) were studied. It was found that the optimal conditions for extraction of phenolics were higher temperature (65 °C) and time (60 min) using ethanol as extractor solvent. In this condition of extraction (A8), total phenolic compounds (TPC) and antioxidant activity (AA) were determined. Additionally, this extract was used to evaluate their effect on antioxidant enzyme activities (superoxide dismutase (SOD) and catalase (CAT)) as well as lipid peroxidation (LP) and protein thiols level (PSH) in the liver and kidneys of normal and diabetic rats. As result, T. catharinensis extract presented TPC content of 23.34 mg EAG/g (equivalent gallic acid) and AA of 34.26 μmol Trolox/g. Phenolic acids (ferulic acid and coumaric acid) and flavonoids (quercetin, rutin and pinocembrin) could be recovered and identified by HPLC. This study indicated an important role of the T. catharinensis extract on free radical inactivation and on the antioxidant defense system in diabetic rats. In fact, the use of T. catharinensis extract restored the normal activity of SOD (p < 0.05) and suppressed malondialdehyde levels in liver and kidney tissues. Thus, the T. catharinensis extract, rich in phenolic compounds, can be responsible for the recover the enzymatic changes in the liver and kidney tissues provoked by diabetes in rats. In addition, the lipid peroxidation rate decreased in the diabetic rats treated with T. catharinensis.

Ischemia-modified albumin as a possible marker of oxidative stress in patients with telogen effluvium

BACKGROUND

Telogen effluvium is the most common form of non-scarring alopecia characterized by diffuse hair loss. Ischemia-modified albumin is a marker of oxidative stress and inflammation.

OBJECTIVE

The aim of this study was to compare the levels of ischemia-modified albumin of telogen effluvium patients with healthy controls.

METHODS

Ninety-one patients diagnosed with telogen effluvium and 35 healthy volunteers were included in the study. Serum ischemia-modified albumin level was determined by a fast-colorimetric method, and albumin cobalt binding test. The results were evaluated statistically.

RESULTS

There was no statistically significant difference between the serum albumin values of patient and control groups (p=0.739). Serum ischemia-modified albumin values were significantly higher in the patients with telogen effluvium than healthy controls (p<0.001).

STUDY LIMITATIONS

Body mass index values of the patient and control groups could not be calculated.

CONCLUSIONS

To the best of the authors' knowledge, this is the first clinical study to investigate the role of oxidative stress in the pathogenesis of telogen effluvium using ischemia-modified albumin as a biomarker. Based on the results of the present study, it can be considered that oxidative stress plays an important role in the pathogenesis of telogen effluvium. There is a need for further studies to support the results of this study, to demonstrate the possible effects of oxidative stress, and to investigate the other oxidative stress markers in the pathogenesis of telogen effluvium.

Role of Ischemia Modified Albumin Serum Levels as an Oxidative Stress Marker in Children with Diabetic Ketoacidosis

AIM AND OBJECTIVE

Ischemia modified albumin (IMA) is a biomarker that has been introduced recently for use in the evaluation of oxidative stress. The aim of this study was to measure the ischemia modified albumin serum levels in pediatric patients with diabetic ketoacidosis (DKA) during acidosis and after the patient recovered from acidosis and to compare these with the control group.

MATERIALS AND METHODS

Pediatric patients with Type I diabetes mellitus (T1DM) who were admitted to the pediatric intensive care unit with the diabetic ketoacidosis were assigned as the study group and healthy children who were admitted to the outpatient clinic and decided as healthy after clinic and laboratory evaluation were selected as the control group. IMA and adjusted IMA levels were evaluated in the blood samples from the control group and the study group when admitted first time to the intensive care unit during the acidosis period (DKA before treatment, DKA-BT), and after recovering from acidosis (DKA after treatment, DKA-AT).

RESULTS

A total of 24 pediatric patients with diabetic ketoacidosis and 30 healthy control children matching age and sex were included in the current study. The albumin levels in pediatric patients with T1DM during DKA-BT were higher than the albumin levels after acidosis (4.101±0.373, 3.854±0.369 g/dL, respectively) (p<0.05). However, there was no significant difference when these values were compared to the control group. Mean values of IMA and Adj-IMA were statistically higher in DKAAT compared to the control group (0.748±0.150 vs 0.591±0.099, p< 0.001; 0.708±0.125 vs 0.607±0.824, p< 0.001, respectively). IMA and adjusted IMA levels measured after recovered from acidosis were significantly higher compared to the level of IMA during DKA (0.748±0.150 vs 0.606±0.105 as absorbance unit, p<0.001; 0.708±0.125 vs 0.625±0.100, p<0.05, respectively).

CONCLUSION

In children with T1DM, even though acidosis recovered following the treatment in diabetic ketoacidosis, which is an oxidative stress marker, the ischemia modified albumin levels and adjusted ischemia modified albumin levels were high.

Serum Thiol-Disulphide Levels in Epileptic Pediatric Patients

Background:

Epilepsy is a serious clinical condition characterized by recurrent seizures. Oxidative stress plays an important role in the etio-pathogenesis of epilepsy. Measurements of serum thiol and disulfide levels were used to evaluate the antioxidant status of the body.

Objective:

The aim of this study was to determine serum levels of thiol and disulfide in epileptic pediatric patients.

Methods:

Ninety patients, 54 epilepsy and 36 controls were included in the study. Serum levels of native thiol total thiol and disulfide were measured and disulfide/native, disulfide / total thiol and native thiol/ total thiol ratios were calculated. Hence, the ratios of disulfide/ native thiol, disulfide / total thiol and native thiol/ total thiol were calculated.

Results:

Serum levels of native thiol, total thiol and disulfide were significantly lower in the epilepsy group than the control group. The ratio of disulfide/native thiol and disulfide / total thiol were significantly higher in the study group than the control group. As well as, the native thiol / total thiol ratio was lower in the epilepsy group than the control group. Native thiol, total thiol and disulfide were significantly lower in the epilepsy group who were taking anti-epileptic drugs than those who were not taking anti-epileptic drugs.

Conclusion:

We demonstrated a meaningful relationship between oxidative stress markers and epilepsy in pediatric patients.

Evaluation of dynamic thiol-disulfide homeostasis in glaucoma patients and the correlation with retinal nerve fiber layer analysis

PURPOSE

The aim of this study was to evaluate thiol/disulfide homeostasis and ischemia-modified albumin levels with primary open-angle glaucoma, ocular hypertension, and control group; also to interpret the correlation between these biochemical parameters and retinal nerve fiber layer analysis.

MATERIAL AND METHODS

In a prospective cross-sectional study, 30 primary open-angle glaucoma cases, 30 ocular hypertension cases, and 30 control subjects were included in the study. Native thiol, total thiol, and disulfide measurements and disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol ratios were evaluated as thiol-disulfide homeostasis. Albumin and ischemia-modified albumin parameters were also evaluated. All cases underwent detailed ophthalmologic examination including visual acuity, retinal nerve fiber layer via optical coherence tomography, intraocular pressure, and central corneal thickness measurements and visual field analysis by 24-2 Swedish Interactive Threshold Algorithm (SITA) Standard visual field test.

RESULTS

Primary open-angle glaucoma group had significantly higher ischemia-modified albumin values than ocular hypertension and control group (p < 0.001). Native thiol and total thiol values of control group were statistically higher than those of primary open-angle glaucoma and ocular hypertension groups. The correlation between the temporal retinal nerve fiber layer value and ischemia-modified albumin, disulfide/native thiol, and disulfide/total thiol values of the primary open-angle glaucoma patients included in the study was moderate correlation in negative direction (r = -0.46, r = -0.39, r = -0.39, respectively), whereas there was a statistically significant moderate correlation in positive direction between the native thiol/total thiol values (r = 0.39) (p < 0.05).

CONCLUSION

These findings have reinforced the role of oxidative stress in the etiopathogenesis of primary open-angle glaucoma, suggesting that the thinning retinal nerve fiber layer may be associated with oxidative stress in favor of prooxidant shift.

[T-786C endothelial nitric oxide gene polymorphism and type 1 diabetic retinopathy in the Algerian population]

INTRODUCTION

Diabetic retinopathy (DR) results from interactions between genetic and environmental factors. We were interested in the endothelial nitric oxide gene (eNOS), given the involvement of this enzyme in functional alterations in the retinal microvasculature in diabetes. The goal of our study was to assess the association of T-786C endothelial nitric oxide synthase (eNOS) gene polymorphism with diabetic retinopathy in the Algerian population.

PATIENTS AND METHODS

Our study enrolled 110 patients with and without DR. All subjects were genotyped for the T786C eNOS polymorphism using the PCR-RFLP method. We also investigated the association between this polymorphism and certain clinical and laboratory characteristics of patients with DR.

RESULTS

A significant increase in the frequency of the CC genotype is noted in subjects without DR (P=0.03). We also report a significant increase in the frequencies of the TT+TC genotypes in individuals with DR (P=0.03). However, the association between the different genotypes and clinical or laboratory profiles in patients with DR reveals that the NO level is lower in subjects carrying the TT genotype (P=0.039).

CONCLUSION

Our preliminary results suggest that the CC genotype could confer protection from type 1 diabetic retinopathy in the Algerian population, while the T allele seems to confer susceptibility.

The evaluation of thiol/disulphide homeostasis in diabetic nephropathy

AIMS

Thiol/disulphide homeostasis plays a critical role in antioxidant defense, and detoxification in body. Although alteration of thiol/disulfide homeostasis had been shown in patients with diabetes, the thiol/disulfide balance in patients with type 2 diabetes and nephropathy is not yet known.

METHODS

Twenty-six healthy volunteers (group 1), and 17 normal albuminuric (group 2), 24 middle albuminuric (group 3), 20 severe proteinuric (group 4) patients with type 2 diabetes were included. Proteinuria was tested by measuring microalbumin/creatinine ratio in spot urine. Thiol/disulphide homeostasis concentrations were measured using method developed by Erel et al. RESULTS: Mean blood urea and creatinine levels were found to be significantly higher and GFR level was found to be significantly lower in group 4 than in the other groups. Native thiol levels are significantly lower in groups with diabetes than in healthy group and in groups 3 and 4, compared to group 2. Total thiol level was significantly lower in groups 3 and 4 than group 1 and 2. Disulphide/native thiol and disulfide/total thiol ratios were significantly higher in the groups with diabetes than in group 1 and in the group 4 than in the group 2.

CONCLUSION

The level of native and total thiols were found to be decreased significantly with the grade of nephropathy in patients with type 2 diabetes and the balance had been disrupted in favor of disulphide. We suggest that deteriorated thiol/disulphide balance may be one of the important factors in the development or progression of diabetes induced nephropathy.

Assessment of thiol/disulfide balance as an oxidative stress marker in children with β-thalassemia major

Objective:

We aimed to investigate the oxidative stress status in children with β-thalassemia major (β-TM) by measuring native thiol (SH), disulfide (SS) and total thiol (SH + SS) plasma levels.

Methods:

This study was carried out from November 2017 to March 2018 at the Pediatric Hematology Clinic of the Harran University Medical Faculty Hospital. Blood specimens were collected from 100 participants, including 50 β-TM patients and 50 controls, and SH, SS and SH+SS levels were detected through a newly developed method.

Results:

SH, SS, SH+SS levels and SS/SH ratio were markedly higher in β-TM patients than in controls. In β-TM group, SH and SH+SS levels were positively correlated with age, albumin and total bilirubin. Serum ferritin level was positively correlated with SH, SH+SS, aspartate transaminase and alanine transaminase.

Conclusions:

We found that the SS/SH ratio was high in patients with β-TM, which shows increased oxidative stress. This ratio may be considered as a tool for the determination of oxidative status in such patients due to easily calculate, suitable for routine use and economical.

Does extracorporeal shockwave lithotripsy therapy affect thiol-disulfide homeostasis?

Objective:

Extracorporeal Shockwave Lithotripsy (ESWL) is a non-invasive method that is effective at crushing stones in the upper urinary tract. Disturbance of the thiol/disulfide homeostasis, in favor of the disulfide, has been shown to be involved in the disease pathogenesis.

Methods:

A total of 36 individuals that underwent ESWL had blood samples collected before ESWL (0hrs), 6hrs, and one week after the ESWL. Sera native and total as wells as disulfide amount was measured using an automated method sodium borohydrate (NaBH₄) reduction. In addition, Ischemia Modified Albumin (IMA) levels were measured using colorimetric assay method.

Results:

Native thiol level was reduced at the 6th hour following ESWL compared to baseline. While the ratios of disulfide level, Disulfide/Total Thiol (DTT), Disulfide/Native Thiol (DNT) and IMA level were increased at the 6th hour following ESWL compared to baseline, they were found to be similar with their baseline values at the end of 1st week. Total thiol and native /total thiol did not show any significant change.

Conclusions:

ESWL treatment disrupts thiol/disulfide homeostasis and the structure of albumin at the acute term. Therefore, it increases protein oxidation and leads to increased oxidative stress. However, this state is transient and returns to normal within the proceeding days.

Patients with type 2 diabetes demonstrate proprioceptive deficit in the knee

AIM

To investigate proprioceptive discrepancies in the lower extremity in persons with type 2 diabetes mellitus (T2DM).

METHODS

In this cross-sectional study, a total of 46 older persons were divided into a T2DM group (n = 23) and a control group who did not have T2DM (n = 23). Participants were given a brief warm up with stretching exercises. Diabetic neuropathy scores were collected prior to proprioceptive testing. For proprioceptive testing, participants performed leg extensions to randomized target positions of 15°, 30°, 45, 60° degrees of elevation in the sagittal plane, each target was repeated a total of four times. Subjects were guided to target positions in the absence of visual feedback via auditory cues from a custom JPS application. When the participant entered the target position, they memorized the location of their limb in space and subsequently attempted to re-locate this position in space. Proprioceptive errors were measured from the target positioned, target remembered, target repositioned protocol.

RESULTS

Proprioceptive accuracy was lower in the diabetic group at all levels of target angle than the control group (P < 0.05). The diabetic group had 46% greater inaccuracy than the control group at all levels of target position. Diabetics also reported greater neuropathy scores than controls in the past 12 mo P < 0.01.

CONCLUSION

Deficits in lower limb localization and greater diabetic neuropathy scores were identified in this study. Our findings may be associated with deafferentation as peripheral neuropathy is a common complication with the disease. These findings may help to explain the declining balance function in the older persons with T2DM which is also commonly reported.