Box A of HMGB1 Maintains the DNA Gap and Prevents DDR-induced Kidney Injury in D-galactose Induction Rats

BACKGROUND/AIM

Disability and mortality rates for renal failure are still increasing. DNA damage and oxidative stress intoxication from body metabolism, high blood glucose, or the environment cause significant kidney damage. Recently, we reported that Box A of HMGB1 (Box A) acts as molecular scissors, producing DNA gaps that prevent DNA damage in kidney cell lines and ultimately reverse aging phenotypes in aging rat models. The present study aimed to demonstrate the potency of Box A in preventing D-galactose (D-gal)-induced kidney injury.

MATERIALS AND METHODS

A Box A expression plasmid was constructed and administered to a rat model. D-gal was injected subcutaneously for eight weeks. Serum was collected to study renal function, and white blood cells were collected for DNA gap measurement. Kidney tissue was also collected for γ-H2AX and NF-κB immunostaining; Senescence-associated (SA)-beta-gal staining; and analysis of the mRNA expression of p16INK4A, TNF-α, and IL-6. Moreover, histopathology analysis was performed using hematoxylin & eosin and Masson trichome staining.

RESULTS

Pretreatment with Box A administration prevented the reduction of DNA gaps and the consequences of the DNA damage response, which include elevated serum creatinine; high serum BUN; an increased positive SA-beta-gal staining area; overexpression of p16INK4A, NF-κB and senescence-associated secretory phenotype molecules, including IL-6, TNF-α; and histological alterations, including tubular dilation and collagen accumulation.

CONCLUSION

Box A effectively prevents DNA gap reduction and all D-gal-induced kidney pathological changes at the molecular, histological, and physiological levels. Therefore, Box A administration is a promising novel therapeutic strategy to prevent DNA-damaging agent-induced kidney failure.

Fetal anemia causes placental and maternal cellular damage: a lesson from fetal hemoglobin Bart's disease

INTRODUCTION

The studies about effect of fetal anemia on placental and maternal molecular changes have rarely been published. This study aimed to compare oxidative stress levels and mitochondrial function in the placenta and maternal peripheral blood mononuclear cell (PMBCs) between anemic fetuses (using fetal Hb Bart's disease as a study model) and non-anemic fetuses.

METHODS

A cross-sectional study was conducted on pregnancies affected by Hb Bart's disease and non-anemic fetuses between 16 and 22 weeks of gestation. Placental tissue and maternal blood for PBMCs were collected after pregnancy termination for determination of oxidative stress and mitochondrial function.

RESULTS

A total of 18 pregnancies affected by Hb Bart's disease and 12 non-anemic fetuses were enrolled. Placental thickness was significantly greater (p-value <0.001) in the affected pregnancies, whereas all Doppler indices of uteroplacental blood flow were comparable. Mitochondrial dysfunction was significantly increased (p-value <0.001) in the placenta of the affected fetuses. In the mothers of affected fetuses, there was an increase in mitochondrial oxidative stress levels with a significant increase in mitochondrial dysfunction in isolated PBMCs (p-value <0.001).

DISCUSSION

In the presence of normal uteroplacental Doppler studies, fetal anemia can induce a significant increase in oxidative stress and mitochondrial dysfunction in the placentas and mothers. The findings support that the placenta can be a source of oxidative stress agents which are released into systemic circulation prior to development of maternal adverse outcomes, and may explain pathophysiology of subsequent preeclampsia in late gestation, as commonly seen in pregnancies affected by fetal Hb Bart's disease, if pregnancy is not terminated.

Cyclosorus Terminans Extract Alleviates Neuroinflammation in Insulin Resistant Rats

High-fat diet consumption for an extended period causes obesity, systemic metabolic disturbance, and brain insulin resistance, resulting in neuroinflammation. Although the beneficial effect of Cyclosorus terminans extract on obesity-related insulin resistance has been demonstrated, little is known about how it affects neuroinflammation and brain insulin resistance in obese rats. Male Wistar rats were given either a normal diet (ND, n = 6) or a high-fat diet (HFD, n = 24) for a total of 14 weeks. At the beginning of the week, 13 rats in the ND group were given vehicle orally for 2 weeks, while rats on HFD diets were randomized to one of four groups and given either vehicle, 100 mg/kg/day of Cyclosorus terminans extract, 200 mg/kg/day of Cyclosorus terminans extract, or 20 mg/kg/day of pioglitazone orally for 2 weeks. After the experimental period, blood and brain samples were taken to assess metabolic and brain parameters. HFD-fed rats had obesity, systemic and brain insulin resistance, brain inflammation, microglial and astrocyte hyperactivity, and brain necroptosis. Treatment with 200 mg/kg/day of Cyclosorus terminans extract and pioglitazone equally attenuated obesity, insulin resistance, brain insulin dysfunction, and neuroinflammation in insulin resistant rats. Our findings suggest that Cyclosorus terminans extract may hold promise as a therapeutic agent for insulin resistance and neuroinflammation in obese conditions.

Observation of Inflammation, Oxidative Stress, Mitochondrial Dynamics, and Apoptosis in Dental Pulp following a Diagnosis of Irreversible Pulpitis

OBJECTIVE

Mitochondrial dynamics play a pivotal role in maintaining the homeostasis of the dental pulp. Inflammation and oxidative stress can trigger changes in mitochondrial dynamics, leading to cell death in the dental pulp. This study aimed to investigate inflammation, oxidative stress, mitochondrial dynamic alterations, and cell death in inflamed pulpal tissues compared to healthy pulp tissues.

METHODS

Pulpal tissues were collected (n=15 per group) from: 1) healthy people as the control and 2) people with clinically diagnosed irreversible pulpitis. Proteins indicating inflammation, oxidative stress, mitochondrial dynamics, and cell death markers were investigated by western blot analysis. A Student's t-test was used to analyse differences between the healthy and irreversible pulpitis groups. A probability of 0.05 was used to indicate statistical significance (p<0.05).

RESULTS

The expression of the proteins, tumour necrosis factor-alpha (TNF-α) and nuclear factor kappa-lightchain-enhancer, by activated B cells (NF-κB) from inflamed pulp tissues were significantly higher than those of control. Compared to controls, 4 hydroxynonenal (4HNE) and dynamin-related protein 1 (Drp1) were significantly higher, while mitofusin 2 (MFN2) and optic atrophy type 1 (OPA1) were significantly lower in inflamed pulp tissues. Bcl-2-associated X protein (Bax), cleaved caspase-3, and cytochrome c were significantly higher in inflamed pulpal tissues compared to controls. In inflamed pulpal tissues, we found a significant increase in the expression of receptor-interacting serine or threonine-protein kinase 1 (RIPK1) but not receptor-interacting serine or threonine-protein kinase 3 (RIPK3).

CONCLUSION

Irreversible pulpitis is associated with inflammation, oxidative stress, alterations in mitochondrial dynamics, and apoptosis in pulpal tissues. (EEJ-2022-01-014).

Myeloid differentiation factor 2 inhibitor and N-acetyl cysteine synergistically reduced left ventricular dysfunction in rats with cardiac ischemia/reperfusion injury

Background

Myeloid differentiation factor 2 inhibitor (MD2i) is a novel anti-inflammatory agent that exerts favorable outcomes in various diseases including cardiac ischemia/reperfusion (I/R) injury. However, whether a potent antioxidant N-acetyl cysteine (NAC) can augment the beneficial effects of MD2i in rats with cardiac I/R injury have never been investigated.

Purpose

We tested the hypothesis that NAC increases the beneficial effects of MD2i against cardiac I/R injury in rats.

Methods

Rats were divided into either a sham (n=6) or cardiac I/R group (n=72). Rats in the I/R group received one of the following 6 treatments (n=12 each) at the onset of reperfusion: vehicle, MD2i at 20 and 40 mg/kg, NAC at 75 and 150 mg/kg, and combined MD2i 20 mg/kg with NAC 150 mg/kg. Left ventricular (LV) function, infarct size, arrhythmia score, and cardiac mitochondrial function and dynamics were determined.

Results

Myocardial infarction, LV dysfunction, and cardiac arrhythmias were observed in rats with cardiac I/R injury, along with mitochondrial dysfunction (Fig. 1). Treatment with MD2i at either 20 or 40 mg/kg effectively reduced LV dysfunction but failed to reduce the infarct size (Fig. 1). NAC at 150 mg/kg, but not at 75 mg/kg, significantly decreased both LV dysfunction and infarct size following cardiac I/R injury (Fig. 1). However, combined treatment exerted even greater efficacy in reducing cardiac I/R injury than monotherapy, through a greater reduction of cardiac mitochondrial dysfunction and mitochondrial fission (Fig. 1). However, no benefit on reducing the arrhythmia score in all groups.

Conclusion

Combined MD2i and NAC treatment exerted a superior cardioprotective effect against cardiac I/R injury than either monotherapy regimen via an improved cardiac mitochondrial function.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): 1. NSTDA Research Chair Grant from the National Science and Technology Development Agency Thailand2. National Research Council of Thailand

Fibroblast growth factor 21 is independently associated with long term mortality in metabolic syndrome

Background

Metabolic syndrome (MetS), a cluster of interrelated cardiovascular risk factors, is associated with increased risk of cardiovascular and non-cardiovascular disease. Fibroblast growth factor 21 (FGF21) plays an important role in metabolic regulation and has been shown to be elevated in MetS. However, role of FGF21 in pathogenesis of cardiovascular disease is still controversial.

Objective

We aimed to identify the association between plasma FGF21 level and long-term mortality in MetS patients.

Methods

Patients with MetS were enrolled in this study during 2015–2017. Blood samples for FGF21 were collected after 12-hour fasting and plasma FGF21 levels were determined using a human FGF21 enzyme-linked immunosorbent assay (ELISA) at the first time of the enrollment. Clinical parameters, and all-cause mortality were recorded. Cox-proportional hazard regression was used for the analysis of association between plasma FGF21 level and all-cause mortality.

Results

A total of 202 Mets patients (male 44.6%) with mean age of 64.3±8.3 years and BMI of 27.3±5.4 kg/m2 were enrolled. After a median follow up of 80 months, 32 (15.8%) patients died. Multivariable Cox proportional hazard regression showed that FGF21 level was independently associated with all-cause mortality after adjustment for age, established cardiovascular disease, estimated glomerular filtration rate and left ventricular ejection fraction. Patients with FGF21 level above median (240 pg/ml) had higher risk of all-cause death compared to patients with FGF21 ≤240 pg/ml (hazard ratio [HR], 3.66; 95% confidence interval [CI], 1.24–10.82; p=0.019) (Figure 1).

Conclusion

FGF21 level is independently associated with long term mortality in metabolic syndrome.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Thailand research fund

Effect of intensive weekend mindfulness-based intervention on BDNF, mitochondria function, and anxiety. A randomized, crossover clinical trial

Background

The previous metanalysis found that Mind-body intervention (MBI) improves neuropsychologic well-being and may increase brain-derived growth factor (BDNF). BDNF is a neurotrophic factor related to neuroplasticity.

Objective

To evaluate the effect of the short intensive MBI compared to control-relaxation on Site on BDNF and examine if this change is related to mitochondria function or stress-related neurohormonal activity.

Methods

Randomized, controlled, two-period cross-over trial conducted in a medical center in Thailand. Healthy-meditation naive Nurse and Occupational Therapy Students, 23 assigned randomly to MBI, and 24 relaxations at the site for 8 h during the weekend. The wash-out period was three months between the two periods. All volunteers took the blood test for BDNF, mitochondrial oxidative phosphorylation (OXPHOS), Cortisol, and Heart rate variability (HRV) measurement before and Visual Analogue Scale for Anxiety (VAS-A), forward and backward digit span after each period.

Results

A total of 40 participants finished the trials. The cross over trial analysis showed a significant treatment effect between MBI and Relaxation on-site for the mean VAS-A as 9.89 (95% CI 4.81 to 19.47; P = 0.001), serum BDNF as 1.24 (95% CI 0.16 to 2.32; P = 0.04), and OXPHOS complex-1 was decreased 0.41 (95% CI 0.03–0.29 p = 0.03). There were no significant differences for digit span, cortisol, and HRV.

Conclusion

In healthy meditation naïve females, even a short period of MBI may increase serum BDNF and reduce anxiety more than relaxation on-site. The more reduction of OXPHOS complex-1 in the mindfulness group suggests oxidative stress may be a more sensitive indicator than stress-related neurohormonal activity.

•

The effects of a short, intensive mindfulness session are scarce.

•

Brain-derived growth factor (BDNF) is impacted by mindfulness-based intervention.

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The results indicate that mindfulness practice increased BDNF.

•

This can be applied to the promotion of women's health.

The roles of HMGB1-produced DNA gaps in DNA protection and aging biomarker reversal

The endogenous DNA damage triggering an aging progression in the elderly is prevented in the youth, probably by naturally occurring DNA gaps. Decreased DNA gaps are found during chronological aging in yeast. So we named the gaps "Youth-DNA-GAPs." The gaps are hidden by histone deacetylation to prevent DNA break response and were also reduced in cells lacking either the high-mobility group box (HMGB) or the NAD-dependent histone deacetylase, SIR2. A reduction in DNA gaps results in shearing DNA strands and decreasing cell viability. Here, we show the roles of DNA gaps in genomic stability and aging prevention in mammals. The number of Youth-DNA-GAPs were low in senescent cells, two aging rat models, and the elderly. Box A domain of HMGB1 acts as molecular scissors in producing DNA gaps. Increased gaps consolidated DNA durability, leading to DNA protection and improved aging features in senescent cells and two aging rat models similar to those of young organisms. Like the naturally occurring Youth-DNA-GAPs, Box A-produced DNA gaps avoided DNA double-strand break response by histone deacetylation and SIRT1, a Sir2 homolog. In conclusion, Youth-DNA-GAPs are a biomarker determining the DNA aging stage (young/old). Box A-produced DNA gaps ultimately reverse aging features. Therefore, DNA gap formation is a potential strategy to monitor and treat aging-associated diseases.

Metabolic reprogramming in epithelial ovarian cancer

Cancer cells usually show adaptations to their metabolism that facilitate their growth, invasiveness, and metastasis. Therefore, reprogramming the energy metabolism is one of the current key foci of cancer research and treatment. Although aerobic glycolysis-the Warburg effect-has been thought to be the dominant energy metabolism in cancer, recent data indicate a different possibility, specifically that oxidative phosphorylation (OXPHOS) is the more likely form of energy metabolism in some cancer cells. Due to the heterogeneity of epithelial ovarian cancer, there are different metabolic preferences among cell types, study types (in vivo/in vitro), and invasiveness. Current knowledge acknowledges glycolysis to be the main energy provider in ovarian cancer growth, invasion, migration, and viability, so specific agents targeting the glycolysis or OXPHOS pathways have been used in previous studies to attenuate tumor progression and increase chemosensitization. However, chemoresistant cell lines exert various metabolic preferences. This review comprehensively summarizes the information from existing reports which could together provide an in-depth understanding and insights for the development of a novel targeted therapy which can be used as an adjunctive treatment to standard chemotherapy to decelerate tumor progression and decrease the epithelial ovarian cancer mortality rate.

The connection of 5-alpha reductase inhibitors to the development of depression

Recent literature connects 5-alpha reductase inhibitors (5-ARIs) with neuropsychiatric adverse effects. Several clinical studies have indicated that former 5-ARIs users had a higher incidence of depressive symptoms and neuropsychiatric side effects than non-users. However, the underlying mechanisms involved in the depression in former 5-ARIs patients, a condition known as "post finasteride syndrome (PFS)", are not thoroughly understood. This review aims to summarize and discuss the association between 5-ARIs and depression as well as possible mechanisms. We used PubMed search terms including "depression", "depressive symptoms", "MDD", "anxiety", or "suicidal idea", and "5-alpha reductase inhibitors", "finasteride", "dutasteride", "5-ARIs". All relevant articles from in vivo and clinical studies from 2002 to 2021 were carefully reviewed. Any contradictory findings were included and debated. The potential mechanisms that link 5-ARIs and depression include alteration in neuroactive steroids, dopaminergic dysfunction, reduced hippocampal neurogenesis, increased neuroinflammation, alteration of the HPA axis, and epigenetic modifications. From this review, we hope to provide information for future studies based on animal experiments, and potential therapeutic strategies for depressive patients with PFS.

Association between Gut Microbiota and Development of Gestational Diabetes Mellitus

Background: It is well known that women with gestational diabetes mellitus (GDM) have gut dysbiosis. However, the dynamic alterations of gut microbiota in GDM are unclear. Additionally, the effects of maternal gut microbiota on the gut microbiota of their newborns remains controversial. The primary objective of this study is to determine the association between types and amounts of gut microbiota and development of gestational diabetes mellitus (GDM). Methods: Eighty-eight pregnant women, including 39 non-GDM and 49 GDM, and their 88 offspring were enrolled. Maternal feces were collected at the time of GDM diagnosis (24–28 weeks of gestation) and at before delivery (≥37 weeks of gestation). Meconium and the first feces of their newborns were also obtained. Results: from quantitative polymerase chain reaction (qPCR) showed that maternal Lactobacillales was decreased from baseline to the time before delivery in both non-GDM and GDM. Firmicutes/Bacteroidetes (F/B) ratio at before delivery was higher in the GDM group. However, there was no difference of neonatal gut microbiota between groups. Conclusions: Although we found only few gut microbiota that demonstrated the difference between GDM and non-GDM, gut microbiota may play a more important role in the development of severer GDM. Therefore, a further study comparing the gut microbiota composition among non-GDM, GDM with diet modification only, GDM with insulin therapy, GDM with successful treatment, and GDM with failure of treatment is needed.

Alterations of mitochondrial dynamics, inflammation and mineralization potential of lipopolysaccharide-induced human dental pulp cells after exposure to N-acetyl cysteine, Biodentine or ProRoot MTA

AIM

To investigate the effects of N-acetyl cysteine (NAC), Biodentine, ProRoot MTA and their combinations, on cell viability, mitochondrial reactive oxygen species (mtROS) production, mineralization and on the expression of genes related to inflammatory cytokine production, mitochondrial dynamics and cell apoptosis of lipopolysaccharide (LPS)-induced human dental pulp cells (hDPCs).

METHODOLOGY

Isolated hDPCs were exposed to 20 μg mL^-1 of Escherichia coli (E. coli) LPS for 24 h, before the experiment, except for the control group. Eight experimental groups were assigned: (i) control (hDPCs cultured in regular medium), (ii) +LPS (hDPCs cultured in LPS medium throughout the experiment), (iii) -LPS/Media, (iv) -LPS/BD, (v) -LPS/MTA, (vi) -LPS/NAC, (vii) -LPS/BD + NAC and (viii) -LPS/MTA + NAC. Cell viability was measured using Alamar blue assay at 24 and 48 h. Production of mtROS was evaluated at 6 and 24 h by MitoSOX Red and MitoTracker Green. The expressions of IL-6, TNF-α, Bcl-2, Bax, Mfn-2 and Drp-1 genes were investigated at 6 h using reverse transcriptase-polymerase chain reaction (RT-PCR). For differentiation potential, cells were cultured in the osteogenic differentiation media and stained using Alizarin red assay at 14 and 21 days. The Kruskal-Wallis test, Mann-Whitney U test and one-way anova were performed for statistical analysis.

RESULTS

NAC was associated with significantly greater LPS-induced hDPC viability (P < 0.05). Both Biodentine and MTA extracts promoted cell survival, whereas the combination of NAC to these material extracts significantly increased the number of viable cells at 24 h (P < 0.05). Biodentine, MTA or NAC did not alter the mtROS level (P > 0.05). NAC supplementation to the MTA extract significantly reduced the level of IL-6 and TNF-α expression (P < 0.05). Regarding mitochondrial dynamics, the use of NAC alone promoted significant Mfn-2/Drp-1 expression (P < 0.05). Most of the groups exhibited a level of Bcl-2/Bax gene expression similar to that of the control group. The increases in mineralization productions were observed in most of the groups, except the LPS group (P < 0.05).

CONCLUSIONS

The antioxidant effect of NAC was not evident under the LPS-induced condition in DPC in vitro. NAC combined either with Biodentine or MTA improved LPS-induced hDPCs survival at 24 h. The combination of NAC with MTA promoted mineralization.

Effects of N-acetyl cysteine on mitochondrial ROS, mitochondrial dynamics, and inflammation on lipopolysaccharide-treated human apical papilla cells

OBJECTIVES

N-Acetyl cysteine (NAC), a well-known antioxidant molecule, has been used to modulate oxidative stress and inflammation. However, no studies have examined the effect of NAC in regenerative endodontic procedures (REPs). Therefore, the aim of this study was to investigate the effects of NAC on cell survival, mitochondrial reactive oxygen species (mtROS) production, and inflammatory and mitochondria-related gene expression on lipopolysaccharide (LPS)-treated apical papilla cells (APCs).

MATERIALS AND METHODS

To assess the NAC concentration, 5 and 10 mM NAC were administered to LPS-treated APCs. Cell proliferation was measured at 24, 48, and 72 h by using AlamarBlue® assay. The 5-mM concentration was further analyzed using different treatment durations: 10 min, 24 h, and the entire study period. The mtROS production was quantified using MitoSOX™ Red and MitoTracker™ Green. RT-PCR was used to detect the expression of IL-6 and TNF-α inflammatory genes and mitochondrial morphology-related genes (Mfn-2/Drp-1 and Bcl-2/Bax) at 6 and 24 h. The statistical significance level was set at 0.05.

RESULTS

Five-millimolar NAC promoted the highest LPS-treated APC proliferation. The use of 24-h NAC stimulated cell proliferation, whereas the entire-period NAC application (> 48 h) significantly reduced the cell number. The mtROS levels were slightly altered after NAC induction. Ten-minute NAC treatment downregulated the IL-6 and TNF-α expression, whereas the expression of Bcl-2/Bax and Mfn-2/Drp-1 ratios was upregulated at 6 h.

CONCLUSIONS

Under the LPS-induced inflammatory condition, NAC stimulated APC survival and decreased inflammation. Ten-minute NAC treatment was sufficient to reduce the level of inflammation and maintain the mitochondrial dynamics.

CLINICAL RELEVANCE

Ten-minute NAC application is sufficient to reduce the level of inflammation and maintain the mitochondrial dynamics. Therefore, NAC may be considered as a potential adjunctive irrigation solution in REPs.

Abstract 15737: Deficiency of Mitochondrial Calcium Uniporter Protects Mouse Hearts From Iron Overload by Attenuating Ferroptosis

Iron (Fe) plays essential roles in many physiological processes. Hereditary hemochromatosis and frequent blood transfusions result in iron overload (IO) and dysfunction of iron-deposited organs including the heart. Although IO-induced cardiomyopathy remains a significant clinical challenge, the underlying mechanism is not well defined. In the present study, we aim to assess the involvement of the mitochondrial Ca uniporter (mCU) in IO-induced cardiac contractile dysfunction and ferroptosis. In a chronic IO model, after receiving Fe (dextran, i.p. 0.6 mg/g, 3 days/wk) for 6 weeks, systolic function (LVEF and LVFS) was reduced in mCU +/+ (WT) compared to mCU -/- (mCU KO). This observation was confirmed in isolated ventricular myocytes where we similarly detected a significant decrease in cell shortening in WT, but not mCU KO myocytes. We found lower Fe levels in mitochondria from mCU KO myocytes compared to WT, while observing the same level of Fe deposition in heart tissue from both groups. The mitochondrial ROS level was lower in mCU KO myocytes vs. WT. Long term cardiac dysfunction may result in myocyte cell death, however, we did not detect apoptosis (TUNEL) in either mCU KO or in WT hearts with cardiac dysfunction after chronic IO. The lipid oxidation level was increased with Fe load suggesting ferroptosis may be involved in IO-induced cardiomyopathy, which was supported by the observation that administration of the selective ferroptosis inhibitor ferrostatin-1 reduced lipid oxidation (4-HNE) and maintained heart function. To further determine the role of mCU in IO-mediated ferroptosis in the heart, we used isolated myocytes from WT and mCU KO and conducted Live/Dead cell viability assays. While Fe (FAC, 0.1-5 mM) induced ferroptosis in a dose-dependent manner, it was prevented by ferrostatin-1 (10 μM), the Fe chelator 2,2'-bipyridyl (2 mM), and MitoTEMPO (5 μM), respectively. Fe-induced ferroptosis in mCU KO myocytes did not occur while the lipid oxidation level (Liperfluo) remained low. In conclusion, mitochondrial Fe uptake, presumably mediated by mCU, accounts for the molecular/cellular mechanisms for Fe-induced myocyte ferroptosis and cardiomyopathy. Cardiac-specific deficiency of mCU prevents the development of Fe induced cardiomyopathy.

Hyperbaric oxygen therapy attenuates D-galactose-induced-age-related cardiac dysfunction through mitigating cardiac mitochondrial dysfunction in pre-diabetic rats

Background

D-galactose (D-gal) induced ageing has been shown to exacerbate left ventricular (LV) dysfunction via worsening of apoptosis and mitochondrial dysfunction in the heart of obese rats. Hyperbaric oxygen therapy (HBOT) has been demonstrated to exert anti-inflammatory and anti-apoptotic effects in multiple neurological disorders. However, the cardioprotective effect of HBOT on inflammation, apoptosis, LV and mitochondrial functions in D-gal induced ageing rats in the presence of obese-insulin resistant condition has never been investigated.

Purpose

We sought to determine the effect of HBOT on inflammation, apoptosis, mitochondrial functions and LV function in pre-diabetic rats with D-gal induced ageing. We hypothesized that HBOT attenuates D-gal induced cardiac mitochondrial dysfunctions and reduces inflammation and apoptosis, leading to improved LV function in pre-diabetic rats.

Methods

Forty-eight male Wistar rats were fed with either normal diet or high-fat diet for 12 weeks. Then, rats were treated with either vehicle groups (0.9% NSS, subcutaneous injection (SC)) or D-gal groups (150 mg/kg/day, SC) for 8 weeks. At week 21, rats in each group were equally divided into 6 sub-groups: normal diet fed rats treated with vehicle (NDV) sham, normal diet fed rats treated with D-gal (NDDg) sham, high fat diet fed rats treated with D-gal (HFDg) sham, high fat diet fed rats treated with vehicle (HFV) + HBOT, NDDg + HBOT and HFDg + HBOT. Sham treated rats were given normal concentration of O2 (flow rate of 80 L/min, 1 ATA for 60 minutes), whereas HBOT treated rats were subjected to 100% O2 (flow rate of 250 L/min, 2 ATA for 60 minutes), given once daily for 2 weeks.

Results

Under obese-insulin resistant condition, D-gal-induced ageing aggravated LV dysfunction (Fig 1A) and impaired cardiac mitochondrial function, increased cardiac inflammatory and apoptotic markers (Fig 1B). HBOT markedly reduced cardiac TNF-α level and TUNEL positive apoptotic cells, and improved cardiac mitochondrial function as indicated by decreased mitochondrial ROS production, mitochondrial depolarization and mitochondrial swelling, resulting in the restoration of the normal LV function in HFV and NDDg rats, compared to sham NDDg rats. In addition, in HFDg treated rats, HBOT attenuated cardiac TNF-α level, TUNEL positive apoptotic cells and cardiac mitochondrial dysfunction, compared to sham HFDg rats, leading to improved cardiac function as indicated by increased %LV ejection fraction (LVEF) (Figure 1).

Conclusion

HBOT efficiently alleviates D-gal-induced-age-related LV dysfunction through mitigating inflammation, apoptosis and mitochondrial dysfunction in pre-diabetic rats.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): 1. The National Science and Technology Development Agency Thailand, 2. Thailand Research Fund Grants

The Effect of Mindfulness-Based Intervention on Brain-Derived Neurotrophic Factor (BDNF): A Systematic Review and Meta-Analysis of Controlled Trials

Background: This systematic review aims to answer three questions. First, how much do mindfulness-based interventions (MBIs) affect peripheral brain-derived neurotrophic factor (BDNF)? Second, do mindfulness exercise-based interventions (exercise-MBIs) and mindfulness meditation-based interventions (meditation-MBIs) affect peripheral BDNF differently? Third, does the age of participants and the accumulative hours of MBI practice affect peripheral BDNF? Methods: We included randomized controlled trials comparing MBI and no intervention in adults (age >18 years) who reported peripheral BDNF. Database searches included PubMed, CINAHL, CENTRAL, PsyInfo, and Scopus. Two reviewers independently selected the studies and assessed the trial quality. We used the standardized mean difference (SMD) as the effect size index and conducted moderator analyses. Results: Eleven studies are included in this systematic review. Five studies applying exercise-MBI and three studies applying meditation-MBI are included in the meta-analysis (N = 479). The pooled effect size shows a significantly greater increase of peripheral BDNF in MBI groups compared to the control groups (k = 8, N = 479, SMD = 0.72, 95% CI 0.31-1.14, I ²= 78%). Significantly more increases of BDNF in the MBI groups are found in both subgroups of exercise-MBI and meditation-MBI. The effect sizes of both subgroups are not significantly different between subgroups (χ² = 0.02, p = 0.88). We find no significant correlation between the effect sizes and the age of participants (r = -0.0095, p = 0.45) or accumulative hours of MBI practice (r = 0.0021, p = 0.57). Conclusion: The heterogeneous data of this small sample-size meta-analysis suggests that MBI can increase peripheral BDNF. Either exercise-MBI or meditation-MBI can increase peripheral BDNF.

Gut Microbiota Profiles of Treated Metabolic Syndrome Patients and their Relationship with Metabolic Health

Metabolic syndrome (MetS) has become a worldwide health issue. Recent studies reveal that the human gut microbiota exerts a significant role in the pathogenesis of this disease. While drug treatments may greatly improve metabolic symptoms, little is known about the gut microbiota composition of these treated MetS patients. This study aimed to characterize the gut microbiota composition of treated-MetS patients and analyse the possibility of using gut microbiota as an indicator of metabolic conditions. 16S rRNA metagenomic sequencing approach was used to profile gut microbiota of 111 treated MetS patients from The Cohort of patients at a high Risk of Cardiovascular Events (CORE)-Thailand registry. Our results show that the gut microbiota profiles of MetS patients are diverse across individuals, but can be classified based on their similarity into three groups or enterotypes. We also showed several associations between species abundance and metabolic parameters that are enterotype specific. These findings suggest that information on the gut microbiota can be useful for assessing treatment options for MetS patients. In addition, any correlations between species abundance and human properties are likely specific to each microbial community.

Liraglutide Suppresses Tau Hyperphosphorylation, Amyloid Beta Accumulation through Regulating Neuronal Insulin Signaling and BACE-1 Activity

Neuronal insulin resistance is a significant feature of Alzheimer's disease (AD). Accumulated evidence has revealed the possible neuroprotective mechanisms of antidiabetic drugs in AD. Liraglutide, a glucagon-like peptide-1 (GLP-1) analog and an antidiabetic agent, has a benefit in improving a peripheral insulin resistance. However, the neuronal effect of liraglutide on the model of neuronal insulin resistance with Alzheimer's formation has not been thoroughly investigated. The present study discovered that liraglutide alleviated neuronal insulin resistance and reduced beta-amyloid formation and tau hyperphosphorylation in a human neuroblostoma cell line, SH-SY5Y. Liraglutide could effectively reverse deleterious effects of insulin overstimulation. In particular, the drug reversed the phosphorylation status of insulin receptors and its major downstream signaling molecules including insulin receptor substrate 1 (IRS-1), protein kinase B (AKT), and glycogen synthase kinase 3 beta (GSK-3β). Moreover, liraglutide reduced the activity of beta secretase 1 (BACE-1) enzyme, which then decreased the formation of beta-amyloid in insulin-resistant cells. This indicated that liraglutide can reverse the defect of phosphorylation status of insulin signal transduction but also inhibit the formation of pathogenic Alzheimer's proteins like Aβ in neuronal cells. We herein provided the possibility that the liraglutide-based therapy may be able to reduce such deleterious effects caused by insulin resistance. In view of the beneficial effects of liraglutide administration, these findings suggest that the use of liraglutide may be a promising therapy for AD with insulin-resistant condition.

Abstract 507: Activation of Transient Receptor Potential Canonical Channel Currents in Iron-Overloaded Cardiac Myocytes

Background: Iron (Fe) overload cardiomyopathy is the leading cause of death in hemochromatotic patients, yet the mechanistic insight is still incomplete and controversial. We investigated alterations of action potentials (APs), ionic currents, and intracellular Ca 2+ (Ca 2+ i ) in Fe-loaded mouse cardiomyocytes, as well as functional impacts of Fe overload on single-cell contraction and whole-heart arrhythmias.

Methods: Cardiomyocytes were isolated from left ventricles of mouse hearts and were superfused with Fe 3+ /8-hydroxyquinoline complex (5-100 μM). APs, L-type Ca 2+ currents (I Ca,L ), total outward K + currents (I K ), and transient receptor potential canonical (TRPC) channel currents were recorded by the patch-clamp technique. Ca 2+ i was evaluated by using Fluo-4. Cell contraction was measured by a video-based edge detection system. Arrhythmias were evaluated in Langendorff-perfused hearts under S 1 -S 2 stimulation protocol.

Results: Persistent Fe (15 μM) treatment prolonged AP duration at 90% repolarization (APD 90 : 46.8 ± 2.8 vs. 203.6 ± 63.4 ms, p<0.05), induced early and delayed afterdepolarizations (EADs: 0 % vs. 45.0 ± 15.0 %; DADs: 4.3 ± 1.4 vs. 27.0 ± 7.0 %, p<0.05, respectively) in mouse cardiomyocytes. Consistently, arrhythmia incidence was increased in Fe 3+ /8-HQ-perfused hearts. Fe treatment decreased peak I Ca,L (16.5 ± 1.7 vs.11.4 ± 1.3 pA/pF, p<0.01) and I K (59.2 ± 3.3 vs. 50.4 ± 3.0 pA/pF, p<0.01), altered Ca 2+ i transient patterns and decreased contractility (4.8 ± 0.5 vs. 3.5 ± 0.4%, p<0.01). During the late phase of Fe treatment, fast Ca 2+ waves and sustained depolarization were induced to generate a secondary (shallow) resting membrane potential (RMP: from -68.8 ± 0.6 to -25.0 ± 3.7 mV) where the myocytes became unexcitable. Gadolinium, a TRPC channel blocker, abolished fast Ca 2+ waves and reversed RMP to the deep level (-62.9 ± 3.5 mV). The involvement of TRPC activation was determined for the first time by recording TRPC current and assessing the effect of functional TRPC channel antibodies.

Conclusions: In mouse cardiomyocytes, Fe overload induced arrhythmogenic APD prolongation and EADs/DADs, aberrant Ca 2+ i dynamics, and impaired contractility. The activation of TRPC channels accounts for an important underlying mechanism.

Effects of dapagliflozin vs vildagliptin on cardiometabolic parameters in diabetic patients with coronary artery disease: a randomised study

AIMS

Sodium glucose co-transporter-2 inhibitors have been shown to reduce cardiovascular events and heart failure in type 2 diabetic (T2D) patients with high cardiovascular risk. Dipeptidyl peptidase-4 inhibitors showed neutral effects and may increase risk of heart failure. We aimed to compare cardiometabolic effects of dapagliflozin and vildagliptin in T2D patients with coronary artery disease (CAD).

METHODS

Forty-nine T2D patients with CAD were randomly assigned to dapagliflozin (n = 25) or vildagliptin (n = 24) for 6 months in a double-blind fashion. Cardiometabolic parameters were collected at baseline and at the end of treatments.

RESULTS

Mean age was 63.2 ± 7.9 years (female 46.9%). Baseline characteristics did not differ between two groups. At 6 months, HbA_1C significantly decreased in both dapaglifozin and vildagliptin groups (0.6 ± 1.0% vs 0.8 ± 1.4%, P = 0.22, respectively). There was no difference between the changes in lipid profiles. Body mass index decreased in patients receiving dapagliflozin, whereas it increased in those receiving vildagliptin (-1.27 [95% confidence interval -2.01, -0.53] vs 1.72 [0.72, 2.72] kg, P < 0.001). The reduction in systolic blood pressure and high-sensitivity troponin T was observed in the dapagliflozin group (-9.87 [-18.00, -1.15] mmHg and 2.49 [-4.50, -0.47] pg/mL) but not in vildagliptin group (-1.97 [-9.42, 5.48] mmHg and 1.98 [-0.02, 3.97] pg/mL). The mean haemoglobin increased in the dapagliflozin group, whereas the mean platelet volume increased in the vildagliptin group. There was no significant change in the inflammatory markers in both the groups.

CONCLUSIONS

The extraglycaemic effects of dapagliflozin and vildagliptin on cardiometabolic parameters in T2D with CAD were different. The more favourable effects of dapagliflozin compared to vildagliptin may have explained the cardiovascular benefits observed only in sodium glucose co-transporter-2 inhibitors.

Combined low-dose testosterone and vildagliptin confers cardioprotection in castrated obese rats

Although a physiological dose of testosterone replacement therapy (p-TRT) has been shown to improve left ventricular (LV) function, some studies reported that it increased the risk of myocardial infarction in testosterone-deprived men. We previously reported that vildagliptin might be used as an alternative to the p-TRT. In this study, we hypothesized that a combined low-dose TRT with vildagliptin exerts greater efficacy than single regimen in improving cardiometabolic function in obese-insulin resistant rats with testosterone deprivation. Male rats were fed on a normal diet or high-fat diet for 12 weeks. Then, they were divided into 2 subgroups; sham operation and orchiectomy (NDO, HFO) and fed their diets for another 12 weeks. At week 25, orchiectomized rats were subdivided into 4 groups, vehicle, p-TRT, vildagliptin, and combined drugs. At week 29, cardiometabolic and biochemical parameters were determined. HFO rats had obese-insulin resistance with a worse LV dysfunction, compared with sham. Vildagliptin and combined drugs effectively reduced insulin resistance. All treatments reduced blood pressure, cardiac autonomic imbalance, LV dysfunction, mitochondrial dysfunction, apoptosis, and increased mitochondrial fusion in NDO and HFO rats. However, p-TRT and combined drugs, but not vildagliptin, reduced mitochondrial fission in NDO and HFO rats. We concluded that combined low-dose TRT with vildagliptin mitigated LV function at a similar level to the p-TRT alone and vildagliptin via improving mitochondrial fusion, reducing mitochondrial dysfunction and apoptosis in testosterone-deprived rats. Our findings suggest that low-dose TRT combined with vildagliptin may be an alternative for p-TRT in conditions of obese-insulin resistance with testosterone deprivation.

Prebiotic prevents impaired kidney and renal Oat3 functions in obese rats

Obesity is health issue worldwide, which can lead to kidney dysfunction. Prebiotics are non-digestible foods that have beneficial effects on health. This study aimed to investigate the effects of xylooligosaccharide (XOS) on renal function, renal organic anion transporter 3 (Oat3) and the mechanisms involved. High-fat diet was provided for 12 weeks in male Wistar rats. After that, the rats were divided into normal diet (ND); normal diet treated with XOS (NDX); high-fat diet (HF) and high-fat diet treated with XOS (HFX). XOS was given daily at a dose of 1000 mg for 12 weeks. At week 24, HF rats showed a significant increase in obesity and insulin resistance associated with podocyte injury, increased microalbuminuria, decreased creatinine clearance and impaired Oat3 function. These alterations were improved by XOS supplementation. Renal MDA level and the expression of AT1R, NOX4, p67^phox, 4-HNE, phosphorylated PKCα and ERK1/2 were significantly decreased after XOS treatment. In addition, Nrf2-Keap1 pathway, SOD2 and GCLC expression as well as renal apoptosis were also significantly reduced by XOS. These data suggest that XOS could indirectly restore renal function and Oat3 function via the reduction of oxidative stress and apoptosis through the modulating of AT1R-PKCα-NOXs activation in obese insulin-resistant rats. These attenuations were instigated by the improvement of obesity, hyperlipidemia and insulin resistance.

Dipeptidyl Peptidase-4 Inhibitor, Vildagliptin, Improves Trabecular Bone Mineral Density and Microstructure in Obese, Insulin-Resistant, Pre-diabetic Rats

OBJECTIVE

Obese insulin resistance and type 2 diabetes mellitus profoundly impair bone mechanical properties and bone quality. However, because several antidiabetes drugs, especially thiazolidinediones, further aggravate bone loss in individuals with diabetes, diabetic osteopathy should not be treated by using simply any glucose-lowering agents. Recently, incretins have been reported to affect osteoblast function positively. The present study aimed to investigate the effects of vildagliptin, an inhibitor of dipeptidyl peptidase-4, on bone of rats with high-fat-diet-induced prediabetes.

METHODS

Male rats were fed a high-fat diet for 12 weeks to induce obese insulin resistance and then treated with vildagliptin for 4 weeks. The effects of the drug on bone were determined by microcomputed tomography and bone histomorphometry.

RESULTS

Vildagliptin markedly improved insulin resistance in these obese insulin-resistant rats. It also significantly increased volumetric bone mineral density. Specifically, vildagliptin-treated obese insulin-resistant rats exhibited higher trabecular volumetric bone mineral density than vehicle-treated obese insulin-resistant rats, whereas cortical volumetric bone mineral density, cortical thickness and area were not changed. Bone histomorphometric analysis in a trabecular-rich area (i.e. tibial metaphysis) revealed greater trabecular bone volume and number and less trabecular separation without change in trabecular thickness, osteocyte lacunar area or cortical thickness in the vildagliptin-treated group.

CONCLUSIONS

Vildagliptin had a beneficial effect on the bone of obese insulin-resistant rats with prediabetes, particularly at the trabecular site. Such benefit probably results from enhanced bone formation rather than from suppressed bone resorption.

Dipeptidyl peptidase-4 inhibitor enhances restoration of salivary glands impaired by obese-insulin resistance

OBJECTIVE

Chronic high-fat diet consumption causes not only obese- insulin resistance, but also leads to pathological changes in salivary glands, including increased mitochondrial dysfunction, apoptosis, oxidative stress, and inflammation. Dipeptidyl peptidase-4 inhibitor (vildagliptin) is an oral anti-diabetic drug, using for treatment of type 2 diabetes. Vildagliptin has been shown to exert beneficial effects on several organs in cases of obese-insulin resistant condition. However, the effect of vildagliptin on salivary glands impaired by obese-insulin resistance has not been investigated. The hypothesis in this study is that vildagliptin confers beneficial effects on the salivary gland impaired by obese-insulin resistance via decreasing mitochondrial dysfunction, apoptosis, oxidative stress, and inflammation.

DESIGN

Twenty-four male Wistar rats were divided into two groups. Each group was fed with either a normal (ND; n=8) or a high fat diet (HFD; n=16) for 16 weeks. At week 13, the HFD-fed rats were subdivided into 2 subgroups to receive either a vehicle or vildagliptin (3mg/kg/day) for 28days via gavage feeding. ND-fed rats were treated with the vehicle. At the end of treatment, metabolic parameters were examined, and rats were killed. Submandibular glands were removed to appraise inflammatory markers, apoptosis and mitochondrial function.

RESULTS

Vehicle-treated HFD-fed rats developed obese-insulin resistance with an increase in oxidative stress, inflammation, apoptosis, and mitochondrial dysfunction in the salivary glands. Vildagliptin therapy reduced oxidative stress, inflammation, apoptosis and mitochondrial dysfunction in salivary gland of HFD-fed rats.

CONCLUSION

Vildagliptin prevented salivary gland injury occurring due to obese-insulin resistance.