mtDNA Single-Nucleotide Variants Associated with Type 2 Diabetes.

Type 2 diabetes (T2D) is a chronic systemic disease with a complex etiology, characterized by insulin resistance and mitochondrial dysfunction in various cell tissues. To explore this relationship, we conducted a secondary analysis of complete mtDNA sequences from 1261 T2D patients and 1105 control individuals. Our findings revealed significant associations between certain single-nucleotide polymorphisms (SNPs) and T2D. Notably, the variants m.1438A>G (rs2001030) (controls: 32 [27.6%], T2D: 84 [72.4%]; OR: 2.46; 95%CI: 1.64-3.78; p < 0.001), m.14766C>T (rs193302980) (controls: 498 [36.9%], T2D: 853 [63.1%]; OR: 2.57, 95%CI: 2.18-3.04, p < 0.001), and m.16519T>C (rs3937033) (controls: 363 [43.4%], T2D: 474 [56.6%]; OR: 1.24, 95%CI: 1.05-1.47, p = 0.012) were significantly associated with the likelihood of developing diabetes. The variant m.16189T>C (rs28693675), which has been previously documented in several studies across diverse populations, showed no association with T2D in our analysis (controls: 148 [13.39] T2D: 171 [13.56%]; OR: 1.03; 95%CI: 0.815-1.31; p = 0.83). These results provide evidence suggesting a link between specific mtDNA polymorphisms and T2D, possibly related to association rules, topological patterns, and three-dimensional conformations associated with regions where changes occur, rather than specific point mutations in the sequence.

Mitochondrial Control Region Variants Related to Breast Cancer.

Breast cancer has an important incidence in the worldwide female population. Although alterations in the mitochondrial genome probably play an important role in carcinogenesis, the actual evidence is ambiguous and inconclusive. Our purpose was to explore differences in mitochondrial sequences of cases with breast cancer compared with control samples from different origins. We identified 124 mtDNA sequences associated with breast cancer cases, of which 86 were complete and 38 were partial sequences. Of these 86 complete sequences, 52 belonged to patients with a confirmed diagnosis of breast cancer, and 34 sequences were obtained from healthy mammary tissue of the same patients used as controls. From the mtDNA analysis, two polymorphisms with significant statistical differences were found: m.310del (rs869289246) in 34.6% (27/78) of breast cancer cases and 61.7% (21/34) in the controls; and m.315dup (rs369786048) in 60.2% (47/78) of breast cancer cases and 38.2% (13/34) in the controls. In addition, the variant m.16519T>C (rs3937033) was found in 59% of the control sequences and 52% of the breast cancer sequences with a significant statistical difference. Polymorphic changes are evolutionarily related to the haplogroup H of Indo-European and Euro-Asiatic origins; however, they were found in all non-European breast cancers.

Adjuvant Therapies in Diabetic Retinopathy as an Early Approach to Delay Its Progression: The Importance of Oxidative Stress and Inflammation.

Diabetes mellitus (DM) is a progressive disease induced by a sustained state of chronic hyperglycemia that can lead to several complications targeting highly metabolic cells. Diabetic retinopathy (DR) is a multifactorial microvascular complication of DM, with high prevalence, which can ultimately lead to visual impairment. The genesis of DR involves a complex variety of pathways such as oxidative stress, inflammation, apoptosis, neurodegeneration, angiogenesis, lipid peroxidation, and endoplasmic reticulum (ER) stress, each possessing potential therapeutic biomarkers. A specific treatment has yet to be developed for early stages of DR since no management is given other than glycemic control until the proliferative stage develops, offering a poor visual prognosis to the patient. In this narrative review article, we evaluate different dietary regimens, such as the Mediterranean diet, Dietary Pattern to Stop Hypertension (DASH) and their functional foods, and low-calorie diets (LCDs). Nutraceuticals have also been assessed in DR on account of their antioxidant, anti-inflammatory, and antiangiogenic properties, which may have an important impact on the physiopathology of DR. These nutraceuticals have shown to lower reactive oxygen species (ROS), important inflammatory factors, cytokines, and endothelial damage biomarkers either as monotherapies or combined therapies or concomitantly with established diabetes management or nonconventional adjuvant drugs like topical nonsteroidal anti-inflammatory drugs (NSAIDs).

Effect of statins on oxidative DNA damage in diabetic polyneuropathy.

Oxidative stress induces nerve damage in type 2 diabetes mellitus and leads to diabetic polyneuropathy (DPN) and can affect the DNA and antioxidant status. Statins have pleiotropic, protective effects on the peripheral nerves of patients with diabetes. The aim of this study was to determine the effects of ezetimibe/simvastatin and rosuvastatin on DNA damage in patients with DPN. This randomized, double-blind, placebo-controlled, clinical trial comprised outpatients from Guadalajara, Mexico. The inclusion criteria were either gender, age 35-80 years, type 2 diabetes, glycated hemoglobin ≤10%, diabetic polyneuropathy stage 1/2, and signed informed consent. Patients who were taking antioxidant therapy or statins, had hypersensitivity to drugs, experienced organ failure, were pregnant or breastfeeding, or had other types of neuropathy were excluded. We assigned patients to placebo, ezetimibe/simvastatin 10/20 mg, or rosuvastatin 20 mg, and the primary outcomes were 8-hydroxy-2'-deoxyguanosine (8-OHdG) for DNA damage, 8-oxoguanine-DNA-N-glycosilase (hOGG1) for DNA repair, and superoxide dismutase (SOD). Seventy-four patients were recruited. Nine patients were included as negative controls. There were no differences in 8-OHdG between the healthy subjects (4.68 [3.53-6.38] ng/mL) and the DPN patients (4.51 [1.22-9.84] ng/mL), whereas the hOGG1 level was 0.39 (0.37-0.42) ng/mL in the healthy subjects and 0.41 (0.38-0.54) ng/mL in patients with DPN at baseline (p = 0.01). SOD decreased significantly in patients with DPN (5.35 [0.01-17.90] U/mL) compared with the healthy subjects (9.81 [8.66-12.61] U/mL) at baseline (p < 0.001). No significant changes in DNA biomarkers were observed in any group between baseline and final levels. We noted a rise in hOGG1 in patients with DPN, without modifications after treatment. There was a slight, albeit insignificant, increase in SOD in patients who were on statins.

Beneficial effects of dark chocolate on exercise capacity in sedentary subjects: underlying mechanisms. A double blind, randomized, placebo controlled trial.

In heart failure patients the consumption of (-)-epicatechin ((-)-Epi)-rich cocoa can restore skeletal muscle (SkM) mitochondrial structure and decrease biomarkers of oxidative stress. However, nothing is known about its effects on exercise capacity and underlying mechanisms in normal, sedentary subjects. Twenty normal, sedentary subjects (∼50 years old) were randomized to placebo or dark chocolate (DC) groups and consumed 20 g of the products for 3 months. Subjects underwent before and after treatment, bicycle ergometry to assess VO2 max and work, SkM biopsy to assess changes in mitochondrial density, function and oxidative stress and blood sampling to assess metabolic endpoints. Seventeen subjects completed the trial. In the DC group (n = 9), VO2 max increased (17% increase, p = 0.056) as well as maximum work (watts) achieved (p = 0.026) with no changes with placebo (n = 8). The DC group evidenced increases in HDL levels (p = 0.005) and decreased triglycerides (p = 0.07). With DC, SkM evidenced significant increases in protein levels for LKB1, AMPK and PGC1α and in their active forms (phosphorylated AMPK and LKB1) as well as in citrate synthase activity while no changes were observed in mitochondrial density. With DC, significant increases in SkM reduced glutathione levels and decreases in protein carbonylation were observed. Improvements in maximum work achieved and VO2 max may be due to DC activation of upstream control systems and enhancement of SkM mitochondria efficiency. Larger clinical studies are warranted to confirm these observations.

Diabetic Polyneuropathy in Type 2 Diabetes Mellitus: Inflammation, Oxidative Stress, and Mitochondrial Function.

Diabetic polyneuropathy (DPN) is defined as peripheral nerve dysfunction. There are three main alterations involved in the pathologic changes of DPN: inflammation, oxidative stress, and mitochondrial dysfunction. Inflammation induces activation of nuclear factor kappa B, activator protein 1, and mitogen-activated protein kinases. Oxidative stress induced by hyperglycemia is mediated by several identified pathways: polyol, hexosamine, protein kinase C, advanced glycosylation end-products, and glycolysis. In addition, mitochondrial dysfunction accounts for most of the production of reactive oxygen and nitrosative species. These free radicals cause lipid peroxidation, protein modification, and nucleic acid damage, to finally induce axonal degeneration and segmental demyelination. The prevalence of DPN ranges from 2.4% to 78.8% worldwide, depending on the diagnostic method and the population assessed (hospital-based or outpatients). Risk factors include age, male gender, duration of diabetes, uncontrolled glycaemia, height, overweight and obesity, and insulin treatment. Several diagnostic methods have been developed, and composite scores combined with nerve conduction studies are the most reliable to identify early DPN. Treatment should be directed to improve etiologic factors besides reducing symptoms; several approaches have been evaluated to reduce neuropathic impairments and improve nerve conduction, such as oral antidiabetics, statins, and antioxidants (alpha-lipoic acid, ubiquinone, and flavonoids).

The effect of ubiquinone and combined antioxidant therapy on oxidative stress markers in non-proliferative diabetic retinopathy: A phase IIa, randomized, double-blind, and placebo-controlled study.

Objective To evaluate the effect of ubiquinone (Coenzyme Q10) and combined antioxidant therapy (CAT) on oxidative stress markers in non-proliferative diabetic retinopathy (NPDR) under clinical management. Study design In a randomized, double-blind, phase IIa, placebo-controlled, clinical trial, three study groups were formed and administered medications as follows: Group 1, Coenzyme Q10; Group 2, CAT; and Group 3, placebo. Methods Serum levels of the products of lipid peroxidation (LPO) and nitrites/nitrates, as markers of oxidative/nitrosative stress, were measured. As antioxidants, the total antioxidant capacity (TAC), catalase activity, and glutathione peroxidase (GPx) activity were measured. Results Baseline serum levels of LPO and nitrites/nitrates were significantly elevated in the three groups vs. healthy group (P < 0.0001), while final levels in the Coenzyme Q10 and CAT groups were decreased vs. normal levels (P < 0.0001). The baseline TAC was consumed in the three groups (P < 0.0001), while final results in the Coenzyme Q10 and CAT groups improved (P < 0.0001). Baseline catalase activity was increased in all groups vs. normal values (P < 0.001), while final levels in the Coenzyme Q10 (P < 0.001) and CAT groups (P < 0.0001) were decreased. GPx behaved similarly to catalase and improved in the final results (P < 0.0001). Discussion Adjunctive antioxidant treatment for 6 months was effective and safe for improving the oxidative stress in NPDR.

The antioxidant effect of ubiquinone and combined therapy on mitochondrial function in blood cells in non-proliferative diabetic retinopathy: A randomized, double-blind, phase IIa, placebo-controlled study.

OBJECTIVES: To evaluate the effect of ubiquinone and combined antioxidant therapy on mitochondrial function in non-proliferative diabetic retinopathy (NPDR) in a randomized, double-blind, phase IIa, placebo-controlled, clinical trial. Three groups of 20 patients were formed: Group 1, ubiquinone; Group 2, combined therapy; and Group 3, placebo (one daily dose for 6 months). METHODS: Fluidity of the submitochondrial membrane in platelets was determined by examining intensity of fluorescence between the monomer (Im) and excimer (Ie). Hydrolytic activity of the mitochondrial F0F1-ATPase was evaluated with the spectrophotometric method. RESULTS: Normal, baseline submitochondrial membrane fluidity, 0.24 ± 0.01 Ie/Im, was significantly diminished in the three study groups vs. normal values (P < 0.0001); placebo, 0.14 ± 0.01 Ie/Im; ubiquinone, 0.14 ± 0.01 Ie/Im; and combined therapy, 0.13 ± 0.00 Ie/Im. Afterward, it increased significantly (P < 0.0001), the ubiquinone group 0.22 ± 0.01 Ie/Im, combined therapy group, 0.19 ± 0.01 Ie/Im; with no changes the placebo group. Baseline hydrolytic activity of the F0F1-ATPase enzyme increased in the three study groups vs. normal values (184.50 ± 7.84 nmol PO4), placebo, 304.12 ± 22.83 nmol PO4 (P < 0.002); ubiquinone, 312.41 ± 25.63 nmol PO4 (P < 0.009); and combined therapy, 371.28 ± 33.50 nmol PO4 (P < 0.002). Afterward, a significant decrease the enzymatic activity: ubiquinone, 213.25 ± 14.19 nmol PO4 (P < 0.001); and combined therapy, 225.55 ± 14.48 nmol PO4 (P < 0.0001). DISCUSSION: Mitochondrial dysfunction significantly improved in groups of NPDR patients treated with antioxidants.

Effects of Ezetimibe/Simvastatin and Rosuvastatin on Oxidative Stress in Diabetic Neuropathy: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.

OBJECTIVE: To evaluate the effects of ezetimibe/simvastatin (EZE/SIMV) and rosuvastatin (ROSUV) on oxidative stress (OS) markers in patients with diabetic polyneuropathy (DPN). METHODS: We performed a randomized, double-blind, placebo-controlled phase III clinical trial in adult patients with Type 2 Diabetes Mellitus (T2DM) and DPN, as evaluated by composite scores and nerve conduction studies (NCS). Seventy-four subjects with T2DM were allocated 1 : 1 : 1 to placebo, EZE/SIMV 10/20 mg, or ROSUV 20 mg for 16 weeks. All patients were assessed before and after treatment: primary outcomes were lipid peroxidation (LPO), and nitric oxide (NO) surrogate levels in plasma; secondary outcomes included NCS, neuropathic symptom scores, and metabolic parameters. Data were expressed as mean ± SD or SEM, frequencies, and percentages; we used nonparametric analysis. RESULTS: LPO levels were reduced in both statin arms after 16 weeks of treatment (p < 0.05 versus baseline), without changes in the placebo group. NO levels were not significantly affected by statin treatment, although a trend towards significance concerning increased NO levels was noted in both statin arms. No significant changes were observed for the NCS or composite scores. DISCUSSION: EZE/SIMV and ROSUV are superior to placebo in reducing LPO in subjects with T2DM suffering from polyneuropathy. This trial is registered with NCT02129231.

Toll-like receptor-1 and receptor-2 and Beta-defensin in postcholecystectomy bile duct injury.

Postcholecystectomy bile duct injuries (BDI) produce hepatic cholestasis and cause infection of the biliary tract. The biliary cells participate in secreting cytokines and in expression of immune response receptors. Toll-like receptors (TLRs) conduct signalling and activate the innate and adaptive inflammatory response. The objective was to determine the serum levels of TLR-2 and the expression of TLR-1 and TLR-2 and ß-defensin in liver biopsies of postcholecystectomy BDI patients. A transverse, analytical study with 2 groups was done. One group included healthy volunteers (control group) and other included 25 postcholecystectomy BDI patients with complete biliary obstruction. Using the Enzyme-linked Immunosorbent Assay (ELISA) technique, serum levels of TLR-2 were determined, and with immunofluorescence the morphologic analysis of TLR-1 and TLR-2 and ß-defensin in liver biopsies of postcholecystectomy BDI patients was performed. The average TLR-2 serum level in the control group was 0.0 pg/mL and in the BDI group, 0.023 ± 0.0045 pg/mL (P < 0.0001, bilateral Mann Whitney U). Immunofluorescence was used to determine the expression in liver biopsies, blood vessels, bile ducts, and hepatic parenchyma where 12 hepatic biopsies were positive for TLR-1 with average of 3213057.74 ± 1071019.25 µm(2); and 7 biopsies were positive for ß-defensin with an average of 730364.33 ± 210838.02 µm(2); and 6 biopsies positive for TLR-2, obtaining an average of 3354364.24 ± 838591.06 µm(2). In conclusion, TLR-1 and TLR-2 and ß-defensin play an important role in the innate antimicrobial defense of the hepatobiliary system.

Effect of necrosectomy and vacuum-assisted closure (VAC) on mitochondrial function and oxidative stress markers in severe acute pancreatitis.

BACKGROUND: Severe acute pancreatitis (SAP) is associated with high morbidity and mortality. OBJECTIVE: To evaluate whether necrosectomy, alone or combined with vacuum-assisted closure (VAC), has any additional beneficial effects on mitochondrial function and/or oxidative stress markers in SAP. METHODS: Patients with SAP, APACHE II score > 8, and inadequate response to management in an intensive care unit were included in a prospective observational study. Sixteen underwent necrosectomy and 24 underwent necrosectomy plus VAC every 48 h. Patients were then categorized as survivors or deceased. Submitochondrial membrane fluidity of platelets and F0F1-ATPase hydrolysis were measured to represent mitochondrial function. Oxidative/nitrosative stress was measured using lipoperoxides (LPOs), nitric oxide (NO), erythrocyte membrane fluidity, and total antioxidant capacity (TAC). RESULTS: Membrane fluidity in submitochondrial particles of platelets remained significantly increased throughout the study, and then eventually rised in deceased patients managed with necrosectomy + VAC vs. survivors (p < 0.041). Hydrolysis was significantly increased from baseline to endpoint in all patients, predominating in those who died after management with necrosectomy (p < 0.03). LPO increased in all patients, and necrosectomy was more efficient for the eventual decrease in survivors (p < 0.039). NO was found to be increased for the baseline-endpoint result among both survivors and deceased patients with both management options. Erythrocyte membrane fluidity was increased in survivors managed with necrosectomy + VAC, and eventually returned to normal (p < 0.045). TAC was found to be consumed in all patients for the duration of the study. CONCLUSIONS: Mitochondrial dysfunction and oxidative/ nitrosative stress with significant systemic antioxidant consumption were found. Necrosectomy was more efficient and better cleared LPOs. Necrosectomy + VAC improved erythrocyte membrane fluidity and increased survival.

Efecto de la necrosectomía y el sistema de cierre asistido al vacío (VAC) sobre función mitocondrial y marcadores de estrés oxidativo en pancreatitis aguda severa / Effect of necrosectomy and vacuum-assisted closure (VAC) on mitochondrial function and oxidative stress markers in severe acute pancreatitis

Antecedentes: la pancreatitis aguda severa (PAS) se asocia con alta morbilidad y mortalidad. Objetivo: evaluar si la necrosectomía sola o necrosectomía + el sistema de cierre al vacío (VAC), ofrece efectos favorables adicionales en la función mitocondrial y/o marcadores de estrés oxidativo en PAS. Métodos: mediante un estudio observacional prospectivo, se incluyeron pacientes con PAS y APACHE II > 8 sin respuesta satisfactoria al manejo en la Unidad de Cuidados Intensivos. Dieciséis pacientes se sometieron a necrosectomía y 24 a necrosectomía + VAC cada 48 h. Se dividieron en sobrevivientes y fallecidos. Se determinó la fluidez de la membrana submitocondrial de las plaquetas y la hidrólisis de la F0F1-ATPasa como función mitocondrial. El estrés oxidativo/nitrosativo se midió mediante lipoperóxidos (LPO), óxido nítrico (ON), fluidez de la membrana de eritrocitos y capacidad antioxidante total (CAT). Resultados: la fluidez de membrana de partículas submitocondriales de plaquetas se mantuvo incrementada significativamente durante todo el estudio y aumentó al final en los fallecidos tratados con necrosectomía + VAC vs. los sobrevivientes (p < 0,041). La hidrólisis se encontró significativamente elevada desde el inicio hasta el final en todos los pacientes, predominando en los que fallecieron tratados con necrosectomía (p < 0,03). Hubo aumento de LPO en todos los pacientes aunque la necrosectomía fue más eficaz en la disminución al final en sobrevivientes (p < 0,039). El ON se encontró incrementado durante el resultado basal-final en sobrevivientes y fallecidos en ambas alternativas de tratamiento. La fluidez de la membrana de eritrocitos se encontró incrementada en los sobrevivientes tratados con necrosectomía + VAC y se normalizó al final (p < 0,045). La CAT se encontró consumida en todos los pacientes durante todo el estudio. Conclusiones: se encontró disfunción mitocondrial y estrés oxidativo/nitrosativo con consumo importante de los antioxidantes sistémicos. La necrosectomía fue más eficiente al eliminar mejor los LPO. La necrosectomía + VAC mejoró la fluidez de la membrana de eritrocitos e incrementó la sobrevida (AU)

Background: Severe acute pancreatitis (SAP) is associated with high morbidity and mortality. Objective: To evaluate whether necrosectomy, alone or combined with vacuum-assisted closure (VAC), has any additional beneficial effects on mitochondrial function and/or oxidative stress markers in SAP. Methods: Patients with SAP, APACHE II score > 8, and inadequate response to management in an intensive care unit were included in a prospective observational study. Sixteen underwent necrosectomy and 24 underwent necrosectomy plus VAC every 48 h. Patients were then categorized as survivors or deceased. Submitochondrial membrane fluidity of platelets and F0F1-ATPase hydrolysis were measured to represent mitochondrial function. Oxidative/nitrosative stress was measured using lipoperoxides (LPOs), nitric oxide (NO), erythrocyte membrane fluidity, and total antioxidant capacity (TAC). Results: Membrane fluidity in submitochondrial particles of platelets remained significantly increased throughout the study, and then eventually rised in deceased patients managed with necrosectomy + VAC vs. survivors (p < 0.041). Hydrolysis was significantly increased from baseline to endpoint in all patients, predominating in those who died after management with necrosectomy (p < 0.03). LPO increased in all patients, and necrosectomy was more efficient for the eventual decrease in survivors (p < 0.039). NO was found to be increased for the baseline-endpoint result among both survivors and deceased patients with both management options. Erythrocyte membrane fluidity was increased in survivors managed with necrosectomy + VAC, and eventually returned to normal (p < 0.045). TAC was found to be consumed in all patients for the duration of the study. Conclusions: Mitochondrial dysfunction and oxidative/ nitrosative stress with significant systemic antioxidant consumption were found. Necrosectomy was more efficient and better cleared LPOs. Necrosectomy + VAC improved erythrocyte membrane fluidity and increased survival (AU)

Effect of rosuvastatin on diabetic polyneuropathy: a randomized, double-blind, placebo-controlled Phase IIa study.

BACKGROUND: Diabetic neuropathy affects 50%-66% of patients with diabetes mellitus. Oxidative stress generates nerve dysfunction by causing segmental demyelinization and axonal degeneration. Antioxidants are considered to be the only etiologic management for diabetic polyneuropathy, and statins such as rosuvastatin increase nitric oxide bioavailability and reduce lipid peroxidation. The aim of this study was to evaluate the antioxidant effect of rosuvastatin in diabetic polyneuropathy. METHODS: We conducted a randomized, double-blind, placebo-controlled Phase IIa clinical trial in patients with type 2 diabetes and diabetic polyneuropathy (DPN) stage ≥1b. We allocated subjects to two parallel groups (1:1) that received rosuvastatin 20 mg or placebo for 12 weeks. Primary outcomes were neuropathic symptom score, disability score, and nerve conduction studies, and secondary outcomes were glycemic control, lipid and hepatic profile, lipid peroxidation, and nerve growth factor beta (NGF-ß) levels. RESULTS: Both groups were of similar age and duration since diagnosis of diabetes and DPN. We observed improvement of DPN in the rosuvastatin group from stage 2a (88.2%) to stage 1b (41.2%), improvement of neuropathic symptom score from 4.5±2 to 2.4±1.8, and significant (P=0.001) reductions of peroneal nerve conduction velocity (from 40.8±2.2 to 42.1±1.6 seconds) and lipid peroxidation (from 25.4±2 to 12.2±4.0 nmol/mL), with no significant change in glycemic control or ß-NGF. CONCLUSION: The severity, symptoms, and nerve conduction parameters of DPN improved after 12 weeks of treatment with rosuvastatin. These beneficial effects appear to be attributable to reductions in lipid peroxidation and oxidative stress.