Assessment of thiol-disulfide and glutathione homeostasis after levothyroxine replacement in individuals with autoimmune or nonautoimmune hypothyroidism.

Objective: Thyroid hormones are known to affect the biosynthesis and degradation of antioxidant compounds, suggesting a possible link between hypothyroidism and oxidative stress. However, there is no clear consensus in the literature regarding this association. The aim of this study was to evaluate oxidative stress markers (extracellular thiol-disulfide homeostasis and intracellular glutathione homeostasis) in patients with hypothyroidism due to autoimmune (Hashimoto's thyroiditis) or nonautoimmune thyroid disease rendered euthyroid after levothyroxine replacement. Subjects and methods: The study included 116 patients admitted to the Taksim Training and Research Hospital (Istanbul, Türkiye). Of these, 50 had hypothyroidism due to Hashimoto's thyroiditis (HT group), 30 had nonautoimmune hypothyroidism (NAIH group), and 36 were healthy controls (control group). All participants were women. Extracellular thiol-disulfide homeostasis and intracellular glutathione homeostasis tests were assessed as oxidative stress markers. Results: Thiol-disulfide homeostasis in both HT and NAIH groups was shifted toward the oxidative spectrum. Compared with the control group, the HT and NAIH groups had lower levels of native (p < 0.001 and p = 0.001, respectively) and total (p = 0.002 and p = 0.012, respectively) thiol, as well as a lower native thiol/total thiol ratio (p < 0.001 for both). The HT group also had higher disulfide levels than the control group (p = 0.027). Reduced glutathione (GSH) and oxidized glutathione (GSSG) values were comparable across all three groups, but the HT and NAIH groups had higher GSSG/GSH (p < 0.001 for both) and GSSG/(GSH+GSSG) ratios (p = 0.003 and p = 0.005, respectively), along with lower GSH/(GSH+GSSG) ratio (p = 0.001 and p = 0.002, respectively) than the control group. Conclusion: Levothyroxine replacement was ineffective in ameliorating oxidative stress in patients with hypothyroidism due to Hashimoto's thyroiditis or nonautoimmune causes, as extracellular thiol-disulfide homeostasis was notably altered in these patients compared with healthy controls. The findings of this study suggest that oxidative stress remains a prevailing issue in patients with autoimmune or nonautoimmune hypothyroidism even after euthyroidism is restored.

Evaluation of Glutathione (GSH) System in Porcine Saliva: Validation and Application of Colorimetric Method.

(1) Reduced glutathione (GSH) is considered the first line of antioxidant defense. During oxidative stress, it is oxidized to glutathione disulphide (GSSG). (2) A simple and quick spectrophotometric method based on sodium borohydride (NaBH4) as a reductant to measure the total and reduced GSH in porcine saliva was analytically validated and evaluated in two situations in this species: (a) in a physiological situation, involving sows during the late lactation and post-weaning periods, and (b) in a situation of sepsis in pigs experimentally induced by LPS administration. (3) The results of the analytical validation showed that the assay was precise and accurate in the porcine saliva samples. Higher total GSH and GSSG and lower reduced GSH were observed in the saliva of sows during the post-weaning period, as well as in pigs with experimentally induced sepsis. (4) In conclusion, the validated assay showed adequate analytical results and could be used to evaluate the GSH system of porcine saliva, as demonstrated during the clinical performance.

The Effect of Glutathione on Development and Prognosis in Non-Muscle-Invasive Bladder Cancer.

Background: Glutathione, along with its related enzymes, constitutes a key antioxidant defense mechanism against oxidative stress and cancer formation in the body. Among urological malignancies, bladder cancer ranks second following prostate cancer. Oxidative stress has significant involvement in the development and prognosis of bladder cancer. This investigation aimed to examine the impact of glutathione on prognosis in patients with non-muscle-invasive bladder cancer. Methods: This study included 98 patients with high grade non-muscle-invasive bladder cancer who had undergone intravesical Bacillus Calmette-Guérin therapy and 30 healthy controls with no history of uroepithelial carcinoma of the bladder. The patients with bladder cancer were evaluated in three subgroups. Group 1 consisted of 41 patients who did not experience recurrence during follow-up, Group 2 included 28 patients who had recurrent tumors, and Group 3 consisted of 29 patients who progressed to muscle-invasive stages. Blood samples were collected from all participants. Blood levels of reduced, oxidized, and total glutathione were measured spectrophotometrically. Results: Reduced glutathione levels significantly differed among the groups (p < 0.001), attributed to the control group exhibiting higher reduced glutathione levels compared with Groups 1, 2, and 3 (p < 0.001). There were no significant differences in reduced glutathione levels between Groups 1 and 2, Groups 1 and 3, or Groups 2 and 3 (p > 0.05). Total glutathione levels varied significantly among the groups (p < 0.001), with the control group having higher levels than Groups 1, 2, and 3 (p < 0.001). No significant differences were detected between any of the paired patient groups in terms of total glutathione levels (p > 0.05). Regarding oxidized glutathione levels, the difference was statistically significant (p < 0.001), with the control group showing lower levels than the remaining three groups (p < 0.001). Paired comparisons revealed no significant differences in oxidized glutathione levels (p > 0.05). Conclusions: This study revealed that glutathione had an effect on the emergence of bladder cancer but did not affect its prognosis. Nevertheless, we recommend that future studies with larger bladder cancer patient cohorts should be conducted to comprehensively determine the impact of glutathione on the prognosis of this cancer.

Evaluation of the dynamic thiol/disulfide homeostasis in patients with chronic venous insufficiency.

OBJECTIVE: There is no study in the literature evaluating the dynamic thiol/disulfide homeostasis in patients with chronic venous insufficiency. Thus, we designed this study to evaluate the dynamic thiol/disulfide homeostasis as a novel indicator of oxidative stress in patients with chronic venous insufficiency. METHODS: This was a prospective case-control study performed at the department of cardiovascular surgery of a tertiary referral hospital in Turkey. A total of 80 (CEAP C3-C6) patients with lower extremity chronic venous insufficiency (as the study group) and 80 healthy subjects (as the control group) were enrolled to the study. The participants' basic demographic and clinical characteristics as well as serum levels of some laboratory parameters including albumin, ferroxidase, myeloperoxidase, native thiol, total thiol, disulphide, native thiol/total thiol, disulphide/native thiol, and disulphide/total thiol were determined, and then compared between the groups. RESULTS: In terms of basic demographic and clinical characteristics, both groups were statistically similar, and there were no significant differences between the groups. When the laboratory parameters were considered, serum ferroxidase and myeloperoxidase levels were detected to be significantly higher, whereas albumin, native thiol, total thiol, and disulphide levels were detected to be significantly lower in the study group than in the control group. CONCLUSIONS: Dynamic thiol/disulphide homeostasis could be considered as an indicator reflecting the oxidative stress status in patients with chronic venous insufficiency.

The Relationship Between Vitamin-D Deficiency and Protein Oxidation Among Obese Children.

Aim: The aim of the study is to examine the relationship between obesity, Vitamin-D deficiency, and protein oxidation. Methods: Thiol-disulfide homeostasis, Vitamin-D, ischemia modified albumin, insulin, and lipid levels were compared among obese, pre-obese and normal-weight healthy children. Results: A total of 136 children (69 boys and 67 girls) were included in the study. The vitamin-D levels of obese children were lower than those of pre-obese and normal weight (p < 0.05). In the normal weight group, total thiol and native thiol were lower in the pubertal period than in adolescence; were higher in those with sufficient Vitamin-D level than those with insufficient and deficient Vitamin-D (p < 0.05). Vitamin-D level was lower in pre-obese girls than boys (p < 0.05). Those with high triglycerides had high disulfide/total thiol, disulfide, and disulfide/native thiol and low native thiol/total thiol (p < 0.05). Conclusion: Thiol-disulfide homeostasis is negatively affected by low vitamin D levels, pubertal period and high triglyceride levels.

An Evaluation of Thiol/Disulphide Homeostasis and HDL Values in Patients with Cholelithiasis: A Prospective Case-control Study.

OBJECTIVE: To determine the changes in thiol/disulphide homeostasis in patients determined with asymptomatic cholelithiasis and to investigate any potential correlation between these thiol-disulphide parameters and HDL cholesterol. STUDY DESIGN: A descriptive, comparative study. PLACE AND DURATION OF STUDY: Ankara City Hospital between 15 September and 31 December 2019. METHODOLOGY: This study included 42 patients aged 18-70 years, who presented at the Gastroenterology Clinic and were diagnosed with cholelithiasis on ultrasound examination. A control group was formed of 51 healthy volunteers aged 18-70 years. Thiol/disulphide homeostasis and HDL cholesterol was noted and compared between the groups. RESULTS: The mean age was 44.16 ± 13.35 years in cholelithiasis patient group and 31.88±13.27 years in the control group. The triglyceride, VLDL, total cholesterol/HDL, and non-HDL levels were significantly higher and HDL level was significantly low in the patient group (both p <0.05). Regarding thiol-disulphide balance, native thiol, total thiol, and albumin values were found to be statistically significantly low in the patient group (p <0.05), and the IMA, index-1, index-2, and index-3 values were significantly high (p <0.05). CONCLUSION: The oxidant/antioxidant balance shifted towards oxidation in patients with asymptomatic gallstones. The non-HDL value was increased. There was a positive correlation between the thiol-disulphide parameters and the non-HDL value. The increasing non-HDL amount could be effective in the pathogenesis of gallstone disease by disrupting the oxidative balance. KEY WORDS: Cholelithiasis, Thiol-disulphide homeostasis, Lipid profile, Non-HDL, HDL, Oxidative stress.

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.

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.

Alteration of thiol disulfide homeostasis and ischemia-modified albumin levels as indicators of oxidative status in patients with silicosis.

The aim of this study was to evaluate the oxidative status in patients with silicosis by detecting dynamic thiol disulfide homeostasis (TDH), ischemia-modified albumin level (IMA) catalase (CAT) activity, and the correlation of these markers with pulmonary function tests. Male ceramic workers with silicosis (n = 91) and healthy individuals (n = 47) were recruited for the study. Radiographic abnormalities of pneumoconiosis were classified into three profusion categories (categories 1, 2, and 3), and patients with silicosis, those with category 1, were defined as group 1 and those with category 2 or 3 were defined as group 2. Plasma levels of native thiol (NT), total thiol (TT), disulfide (Ds), IMA, and CAT activities were determined. Pulmonary function tests of groups were compared. NT, TT, and NT/TT ratios were significantly lower in groups 1 and 2 than the control group (p < 0.05). These did not differ between patients with silicosis (groups 1 and 2) and control group (p = 0.421). Ds/NT and Ds/TT ratios were significantly higher in group 2 than the control group (p < 0.05). NT, TT, and Ds did not differ significantly between groups 1 and 2. The oxidant biomarker IMA was higher (p < 0.001), and the antioxidant parameters albumin and CAT were lower in groups 1 and 2 (p < 0.001) compared with the control group. The mean FEV1act, FVCact, forced expiratory volume in 1 second/forced vital capacity (%), and value of 25-75 percent maximum expiratory flow were significantly lower in groups 1 and 2 than control group. We have used a novel colorimetric method to assess TDH in patients with silicosis. Alteration of plasma thiol/disulfide homeostasis and IMA levels might be novel indicators of oxidative stress in silicosis.

Thiol/Disulfide Homeostasis as an Early Biomarker to Differentiate Sepsis from Pneumonia in Intensive Care Units.

BACKGROUND: It is possible that patients with pneumonia may also have sepsis and the separation of these two clinical entities may cause some trouble to clinicians. OBJECTIVE: In order to separate a patient with pneumonia and a patient with sepsis, we qualify thiol/disulfide homeostasis as a potential biomarker. METHODS: This study was designed between February 2018 - February 2019 prospectively. All patients in the intensive care unit with pneumonia and sepsis were enrolled in the study. At the time of hospitalization, thiol/disulfide homeostasis was measured. Patients diagnosed with sepsis and pneumonia were compared, in regards to thiol/disulfide homeostasis. RESULTS: During research period, 103 patients with sepsis and 120 patients with pneumonia were enrolled into the study. When we compared native-thiol, total-thiol, and disulfide levels in both sepsis and pneumonia patients, we had similar results (p>0.05). In sepsis group, index-1 (disulfide/native thiol ratio) and index-2 (disulfide/total thiol ratio) were found to be statistically higher than the pneumonia group, and index-3 (native thiol/total thiol ratio) was statistically lower than the pneumonia group (p=0.020, p= 0.021, p=0.021, respectively). CONCLUSION: In this study, we showed that thiol/disulfide homeostasis could be used as new markers in the early period in order to separate patients with sepsis and patients with pneumonia.

Thiols and ceruloplasmin levels in serum of children with attention deficit hyperactivity disorder: A cross-sectional study.

Attention deficit hyperactivity disorder (ADHD) is a childhood onset disorder with well-known findings that include impulsivity, hyperactivity, and inattention. This study aims to explore the relationship between the levels of ceruloplasmin, native thiol, total thiol, and disulfide and ADHD by comparing case and control groups. The study case group comprised 50 children aged 6-16 years who had been diagnosed with ADHD. The control group included 47 healthy children. Clinical interviews were conducted and the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version Turkish Adaptation and the Conners Parent Rating Scale were administered. Additionally, blood samples were taken and native thiol, total thiol, disulfide, and ceruloplasmin levels measured. In the ADHD group, the mean native thiol, total thiol, and disulfide levels were significantly lower than the control group. There was no significant difference between the ADHD and control groups in ceruloplasmin levels. Total thiol and native thiol levels were inversely correlated with scores on the Conners Inattention and Hyperactivity subscales; total thiol was negatively correlated with the ADHD index. Thiol-disulfide homeostasis was impaired in ADHD children and was related to symptom severity. Oxidative stress balance may play a role in ADHD.

Clinical and laboratory features of COVID-19: Predictors of severe prognosis.

BACKGROUND: Coronavirus disease 2019 (COVID-19) emerged first in December 2019 in Wuhan, China and quickly spread throughout the world. Clinical and laboratory data are of importance to increase the success in the management of COVID-19 patients. METHODS: Data were obtained retrospectively from medical records of 191 hospitalized patients diagnosed with COVID-19 from a tertiary single-center hospital between March and April 2020. Prognostic effects of variables on admission among patients who received intensive care unit (ICU) support and those who didn't require ICU care were compared. RESULTS: Patients required ICU care (n = 46) were older (median, 71 vs. 43 years), with more underlying comorbidities (76.1% vs. 33.1%). ICU patients had lower lymphocytes, percentage of large unstained cell (%LUC), hemoglobin, total protein, and albumin, but higher leucocytes, neutrophils, neutrophil-lymphocyte ratio (NLR), monocyte-lymphocyte ratio (MLR), platelet-lymphocytes ratio (PLR), urea, creatinine, aspartate amino transferase (AST), lactate dehydrogenase (LDH), and D-dimer when compared with non-critically ill patients (p < 0.001). A logistic regression model was created to include ferritin, %LUC, NLR, and D-dimer. %LUC decrease and D-dimer increase had the highest odds ratios (0.093 vs 5.597, respectively) to predict severe prognosis. D-dimer, CRP, and NLR had the highest AUC in the ROC analysis (0.896, 0.874, 0.861, respectively). CONCLUSIONS: The comprehensive analysis of clinical and admission laboratory parameters to identify patients with severe prognosis is important not only for the follow-up of the patients but also to identify the pathophysiology of the disease. %LUC decrease and D-dimer, NLR, and CRP increases seem to be the most powerful laboratory predictors of severe prognosis.

Is ischemia associated with the formation of White matter lesions in migraine?

OBJECTIVE: White matter lesions (WMLs) are more common in migraine patients than in the normal population. Ischemia/hypoxia and oxidative stress are considered to play a role in WMLs formation. This study aimed to investigate ischemia-modified albumin (IMA), ferroxidase and thiol/disulfide homeostasis in migraineurs with and without WMLs. PATIENTS AND METHODS: Sixty-two migraineurs with WML, 59 migraineurs without WML and 61 controls were included in the study. All participants underwent brain MRI. WMLs was evaluated according to the Fazekas scale. IMA, ferroxidase, total thiol, native thiol and disulfide measurements were carried out in all participants. RESULTS: The IMA levels were higher in the migraine groups compared to the control group (p < 0.001) and in the WML group compared to non-WML (p < 0.001). The total and native thiol levels were higher in the non-WML group compared to the control and WML groups (p < 0.001 for both). The disulfide levels were similar between the control and non-WML groups, but they were significantly lower in the WML group compared to the control and non-WML groups. There was no significant difference between the groups in terms of the ferroxidase levels (p = 0.092). The thiol/disulfide, IMA and ferroxidase levels were not significantly correlated with the frequency and duration of attacks, severity of pain and disability due to migraine. CONCLUSION: Increased serum IMA levels in migraineurs point to the role of ischemia/hypoxia, and increased total thiol and decreased disulfide levels indicate an oxidant/antioxidant imbalance in migraine. Ischemia/hypoxia may play a role in WMLs formation in migraine.

The change in Thiol-Disulphide Homeostasis levels as an oxidative stress marker after varicocelectomy: Is there a relationship with sperm parameters?

One of the most important causes of varicocele-related infertility is oxidative stress (OS). One of the markers considered as an indicator of OS is thiol-disulphide homeostasis (TDH). Based on the hypothesis that OS should decrease after varicocelectomy in the light of this information, in our current study, we investigated the relationship between TDH levels and sperm parameters. The data of 56 infertile varicocele men were prospectively analysed. The post-operative total and native thiol levels were significantly higher than those pre-operative total and native thiol levels (477.7 & 436.7 nmol/L, 417.6 & 372.1 nmol/L). Positive correlation was found between total thiol change and change in semen volume (ρ: .277, p: .039), ratio of spermatozoa with normal morphology (ρ: .342, p: .01), progressive (ρ: .334, p: .012) and nonprogressive motility (ρ: .385, p: .003). Positive correlation was also found between native thiol change and semen volume (ρ: .349, p: .008), ratio of spermatozoa with normal morphology (ρ: .362, p: .006), progressive (ρ: .297, p: .026) and nonprogressive motility (ρ: .368, p: .005). Change in the level of TDH was found as positively correlated with progressive and nonprogressive motility change. According to these results, OS decreases with varicocelectomy in infertile patients and TDH can be used as a useful method for measuring OS.

Thiol-Disulfide Homeostasis, Serum Ferroxidase Activity, and Serum Ischemia Modified Albumin Levels in Childhood Iron Deficiency Anemia.

Aim: The aim is to compare the markers of oxidative stress in iron deficient children to that of non-anemic children. Method: Serum thiol-disulfide level, ferroxidase activity and ischemia-modified albumin (IMA) levels were compared between iron deficiency anemia (IDA) and non-anemic children. Results: A total of 117 children, 66 with IDA and 51 non-anemic children were included in the study. Disulfide, disulfide/native thiol, and disulfide/total thiol levels were significantly higher in the IDA group (p: 0.001). Serum ferroxidase levels were significantly lower in the IDA group (p: 0.04); but there was no significant difference between the two groups regarding serum IMA levels (p: 0.42). There was a weak negative correlation between disulfide and serum hemoglobin (p: 0.004), iron (p: 0.041), and ferritin (p: 0.023) levels while there was a weak positive correlation between ferroxidase activity and these parameters. Conclusion: There is an increased protein oxidation in children with IDA compared with non-anemic controls.

Thiol-Disulfide Homeostasis and Serum Ischemia Modified Albumin Levels in Patients with Primary Open-Angle Glaucoma.

Aim: Glaucoma is an optic neuropathy causing progressive impairment of visual functions. We aimed to assess the alterations in thiol-disulfide homeostasis and serum ischemia modified albumin (IMA) levels, which are the determinants of antioxidant status, in patients with primary open-angle glaucoma (POAG). Material and Method: A total of 140 eyes from 70 patients with POAG and 174 eyes of 87 healthy, control cases were included in the study. All study participants underwent a complete ophthalmic evaluation. Alterations in serum thiol-disulfide homeostasis and IMA levels were measured in all participants. Results: IMA levels were significantly higher in glaucoma group (p:0.001). Native thiol, Total thiol and Native/Total thiol ratio were significantly decreased while Disulfide, Disulfide/Native thiol, and Disulfide/Total thiol ratios were significantly higher in glaucoma group (p:0.001). There was no significant difference regarding central corneal thickness (CCT), iridocorneal angle, albumin, IMA and adjusted IMA levels in patients with different stages of glaucoma. In correlation analysis, there was a negative correlation between Native thiol, Total thiol and Native/Total thiol ratio and disease period, number of daily drops required and stage of the disease in glaucoma patients. There was also a positive correlation between Disulfide, Disulfide/Native thiol and Disulfide/Total thiol levels and the disease activity. Conclusion: In patients with POAG, thiol-disulfide homeostasis is disturbed in the favor of pro-oxidant molecules and IMA levels are increased, indicating the presence of augmented oxidative stress. In that aspect, systemic and local anti-oxidant treatments may be new targets in glaucoma treatment. Larger, prospective studies about the role of anti-oxidants in prevention and treatment of POAG are warranted.

Thiol-Disulfide Homeostasis, Serum Ferroxidase Activity, and Serum Ischemia Modified Albumin Levels in Neonatal Jaundice.

AIM: Hyperbilirubinemia causes oxidative stress. METHOD: We evaluated three oxidative stress markers in hyperbilirubinemic neonates (native/total thiol levels, serum ferroxidase activity and ischemia modified albumin (IMA), comparing these levels to levels in a control group to determine which indicators were the most sensitive. RESULTS: Serum from 124 term infants (67 with pathologic jaundice and 57 controls) were evaluated. Native/total thiol ratio was significantly lower (p:0.021) while disulfide levels were significantly higher (p:0.001) in the jaundiced group. There was no significant difference in ferroxidase (p:0.603) or IMA (p:0.251) levels. CONCLUSION: Altered thiol/disulfide homeostasis in the favor of disulfide indicates augmented oxidative stress in jaundiced term infants. The lack of alteration in ferroxidase or IMA levels suggests these latter alterations take more time or more severe oxidative stress to become altered or are not as sensitive as the thiol/disulfide ratio to detect oxidative stress states.

Evaluation of fetal serum thiol/disulphide homeostasis in deliveries complicated by nuchal cord.

Aim: To investigate the serum thiol/disulphide homeostasis in deliveries complicated by nuchal cord (NC) and to compare the results with healthy deliveries (without NC). Methods: This prospective controlled study included 48 pregnant women complicated by NC and 48 similar gestational aged healthy pregnant women during labor. Fetal umbilical cord serum samples were collected during labor and the thiol/disulphide homeostasis was measured by using an automated assay method. The patients were followed up until end of the delivery and perinatal outcomes were recorded. Results: Fetal umbilical cord native thiol, total thiol, and disulphide levels as well as disulphide/native thiol and disulphide/total thiol ratios are impaired in labor with the presence of NC. There were no statistically significant differences in terms of maternal and gestational age at delivery and maternal number of gravida and parity, fetal gender, fifth Apgar scores <7, mode of delivery and fetal birth weight between groups. The group of patients with NC had higher emergency C/S numbers indicated for fetal distress and lower first Apgar scores <7. There were no neonatal intensive care unit admissions among these babies. Conclusions: Maternal serum thiol/disulphide homeostasis reflect transient effects of NC during labor regardless of labor type. Vaginal delivery can be safely and successfully performed in pregnancies complicated with NC.

Vitamin D supplementation does not improve plasma thiol/disulfide homeostasis.

BACKGROUND: Impairment of thiol/disulfide homeostasis, as well as vitamin D deficiency, are responsible for the pathophysiology of many acute and chronic diseases. This study examined the relationship between thiol/disulfide homeostasis and vitamin D level and supplementation. METHODS: A total of 203 healthy children were included in the study. The participants were divided into four groups according to 25-hydroxyvitamin D (25(OH)D) level: group 1, severe deficiency (<10 ng/mL); group 2, deficiency (10-20 ng/mL); group 3, insufficiency (20-30 ng/mL); and group 4, sufficiency (≥30 ng/mL). Furthermore, group 5 was defined as being on vitamin D supplementation. RESULT: Native thiol was lower in group 5 than in groups 2-4 (P = 0.003). Disulfide was higher in groups 1, 4 and 5 than groups 2 and 3 (P < 0.001). Total thiol was lower in group 5 than in group 4 (P = 0.032). The ratio of native thiol/total thiol was lower in groups 1 and 5 compared with groups 2 and 3, and in group 4 compared with group 3 (P < 0.001). The ratios of disulfide/total thiol and disulfide/native thiol were higher in groups 1 and 5 than in groups 2 and 3 whereas only the disulfide/total thiol ratio was higher in group 4 than in group 3 (P < 0.001). CONCLUSIONS: In healthy children, severe deficiency of vitamin D causes impairment of thiol/disulfide homeostasis and increases protein oxidation, which cannot be reversed by external vitamin D supplementation.