Redox imbalance and mitochondrial abnormalities in the diabetic lung

Deciphering the molecular mechanism of Bu Yang Huan Wu Decoction in interference with diabetic pulmonary fibrosis via regulating oxidative stress and lipid metabolism disorder

BACKGROUND

Diabetes mellitus type 2 and pulmonary fibrosis have been found to be closely related in clinical practice. Diabetic pulmonary fibrosis (DPF) is a complication of diabetes mellitus, but its treatment has yet to be thoroughly investigated. Bu Yang Huan Wu Decoction (BYHWD) is a well-known traditional Chinese prescription that has shown great efficacy in treating pulmonary fibrosis with hypoglycemic and hypolipidemic effects.

METHODS

The active ingredients of BYHWD and the corresponding targets were retrieved from the Traditional Chinese Medicine Systematic Pharmacology Database (TCMSP) and SymMap2. Disease-related targets were obtained from the GeneCard, OMIM and CTD databases. GO enrichment and KEGG pathway enrichment were carried out using the DAVID database. AutoDock Vina software was employed to perform molecular docking. Molecular dynamics simulations of proteinligand complexes were conducted by Gromacs. Animal experiments were further performed to validate the effects of BYHWD on the selected core targets, markers of oxidative stress, serum lipids, blood glucose and pulmonary fibrosis.

RESULTS

A total of 84 active ingredients and 830 target genes were screened in BYHWD, among which 56 target genes intersected with DPF-related targets. Network pharmacological analysis revealed that the active ingredients can regulate target genes such as IL-6, TNF-α, VEGFA and CASP3, mainly through AGE-RAGE signaling pathway, HIF-1 signaling pathway and TNF signaling pathway. Molecular docking and molecular dynamics simulations suggested that IL6-astragaloside IV, IL6-baicalein, TNFα-astragaloside IV, and TNFα-baicalein docking complexes could bind stably. Animal experiments showed that BYHWD could reduce the expression of core targets such as VEGFA, CASP3, IL-6 and TNF-α. In addition, BYHWD could reduce blood glucose, lipid, and MDA levels in DPF while increasing the activities of SOD, CAT and GSH-Px. BYHWD attenuated the expression of HYP and collagen I, mitigating pathological damage and collagen deposition within lung tissue.

CONCLUSIONS

BYHWD modulates lipid metabolism disorders and oxidative stress by targeting the core targets of IL6, TNF-α, VEGFA and CASP3 through the AGE-RAGE signaling pathway, making it a potential therapy for DPF.

Metformin attenuates lung ischemia-reperfusion injury and necroptosis through AMPK pathway in type 2 diabetic recipient rats

BACKGROUND

Diabetes mellitus (DM) can aggravate lung ischemia-reperfusion (I/R) injury and is a significant risk factor for recipient mortality after lung transplantation. Metformin protects against I/R injury in a variety of organs. However, the effect of metformin on diabetic lung I/R injury remains unclear. Therefore, this study aimed to observe the effect and mechanism of metformin on lung I/R injury following lung transplantation in type 2 diabetic rats.

METHODS

Sprague-Dawley rats were randomly divided into the following six groups: the control + sham group (CS group), the control + I/R group (CIR group), the DM + sham group (DS group), the DM + I/R group (DIR group), the DM + I/R + metformin group (DIRM group) and the DM + I/R + metformin + Compound C group (DIRMC group). Control and diabetic rats underwent the sham operation or left lung transplantation operation. Lung function, alveolar capillary permeability, inflammatory response, oxidative stress, necroptosis and the p-AMPK/AMPK ratio were determined after 24 h of reperfusion.

RESULTS

Compared with the CIR group, the DIR group exhibited decreased lung function, increased alveolar capillary permeability, inflammatory responses, oxidative stress and necroptosis, but decreased the p-AMPK/AMPK ratio. Metformin improved the function of lung grafts, decreased alveolar capillary permeability, inflammatory responses, oxidative stress and necroptosis, and increased the p-AMPK/AMPK ratio. In contrast, the protective effects of metformin were abrogated by Compound C.

CONCLUSIONS

Metformin attenuates lung I/R injury and necroptosis through AMPK pathway in type 2 diabetic lung transplant recipient rats.

Dihydrolipoyl dehydrogenase promotes white adipocytes browning by activating the RAS/ERK pathway and undergoing crotonylation modification

Acetylation modification has a wide range of functional roles in almost all physiological processes, such as transcription and energy metabolism. Crotonylation modification is mainly involved in RNA processing, nucleic acid metabolism, chromosome assembly and gene expression, and it's found that there is a competitive relationship between crotonylation modification and acetylation modification. Previous study found that dihydrolipoyl dehydrogenase (DLD) was highly expressed in brown adipose tissue (BAT) of white adipose tissue browning model mice, suggesting that DLD is closely related to white fat browning. This study was performed by quantitative real-time PCR (qPCR), Western blotting (WB), Enzyme-linked immunosorbent assay (ELISA), Immunofluorescence staining, JC-1 staining, Mito-Tracker Red CMXRos staining, Oil red O staining, Bodipy staining, HE staining, and Blood lipid quadruple test. The assay revealed that DLD promotes browning of white adipose tissue in mice. Cellularly, DLD was found to promote white adipocytes browning by activating mitochondrial function through the RAS/ERK pathway. Further studies revealed that the crotonylation modification and acetylation modification of DLD had mutual inhibitory effects. Meanwhile, DLD crotonylation promoted white adipocytes browning, while DLD acetylation did the opposite. Finally, protein interaction analysis and Co-immunoprecipitation (Co-IP) assays identified Sirtuin3 (SIRT3) as a decrotonylation and deacetylation modification enzyme of regulates DLD. In conclusion, DLD promotes browning of white adipocytes by activating mitochondrial function through crotonylation modification and the RAS/ERK pathway, providing a theoretical basis for the control and treatment of obesity, which is of great significance for the treatment of obesity and obesity-related diseases in the future.

Lung molecular and histological changes in type 2 diabetic rats and its improvement by high-intensity interval training

BACKGROUND

Type 2 diabetes (T2D) leads to serious respiratory problems. This study investigated the effectiveness of high-intensity interval training (HIIT) on T2D-induced lung injuries at histopathological and molecular levels.

METHODS

Forty-eight male Wistar rats were randomly allocated into control (CTL), Diabetes (Db), exercise (Ex), and Diabetes + exercise (Db + Ex) groups. T2D was induced by a high-fat diet plus (35 mg/kg) of streptozotocin (STZ) administration. Rats in Ex and Db + Ex performed HIIT for eight weeks. Tumor necrosis factor-alpha (TNFα), Interleukin 10 (IL-10), BAX, Bcl2, Lecithin, Sphingomyelin (SPM) and Surfactant protein D (SPD) levels were measured in the bronchoalveolar lavage fluid (BALF) and malondialdehyde (MDA) and total antioxidant capacity (TAC) levels were measured in lung tissue. Lung histopathological alterations were assessed by using H&E and trichrome mason staining.

RESULTS

Diabetes was significantly associated with imbalance in pro/anti-inflammatory, pro/anti-apoptosis and redox systems, and reduced the SPD, lecithin sphingomyelin and alveolar number. Performing HIIT by diabetic animals increased Bcl2 (P < 0.05) and IL10 (P < 0.01) levels as well as surfactants components and TAC (P < 0.05) but decreased fasting blood glucose (P < 0.001), TNFα (P < 0.05), BAX (P < 0.05) and BAX/Bcl2 (P < 0.001) levels as well as MDA (P < 0.01) and MDA/TAC (P < 0.01) compared to the diabetic group. Furthermore, lung injury and fibrosis scores were increased by T2D and recovered in presence of HIIT.

CONCLUSION

These findings suggested that the attenuating effect of HIIT on diabetic lung injury mediated by reducing blood sugar, inflammation, oxidative stress, and apoptosis as well as improving pulmonary surfactants components.

Diabetic Pneumopathy- A Novel Diabetes-associated Complication: Pathophysiology, the Underlying Mechanism and Combination Medication

BACKGROUND

The "diabetic lung" has been identified as a possible target organ in diabetes, with abnormalities in ventilation control, bronchomotor tone, lung volume, pulmonary diffusing capacity, and neuroadrenergic bronchial innervation.

OBJECTIVE

This review summarizes studies related to diabetic pneumopathy, pathophysiology and a number of pulmonary disorders including type 1 and type 2 diabetes.

METHODS

Electronic searches were conducted on databases such as Pub Med, Wiley Online Library (WOL), Scopus, Elsevier, ScienceDirect, and Google Scholar using standard keywords "diabetes," "diabetes Pneumopathy," "Pathophysiology," "Lung diseases," "lung infection" for review articles published between 1978 to 2023 very few previous review articles based their focus on diabetic pneumopathy and its pathophysiology.

RESULTS

Globally, the incidence of diabetes mellitus has been rising. It is a chronic, progressive metabolic disease. The "diabetic lung" may serve as a model of accelerated ageing since diabetics' rate of respiratory function deterioration is two to three-times higher than that of normal, non-smoking people.

CONCLUSION

Diabetes-induced pulmonary dysfunction has not gained the attention it deserves due to a lack of proven causality and changes in cellular properties. The mechanism underlying a particular lung illness can still only be partially activated by diabetes but there is evidence that hyperglycemia is linked to pulmonary fibrosis in diabetic people.

SIRT3 Regulates Levels of Deacetylated SOD2 to Prevent Oxidative Stress and Mitochondrial Dysfunction During Oocyte Maturation in Pigs

Mammalian oocyte maturation relies on mitochondrial ATP production, but this can lead to damaging reactive oxygen species (ROS). SIRT3, a mitochondrial sirtuin, plays a critical role in regulating mitochondrial redox balance in mouse oocytes under stress; however, its specific roles in porcine oocytes remain unclear. In this study, we utilized the SIRT3 inhibitor 3-TYP to investigate SIRT3's importance in porcine oocyte maturation. Our findings revealed that SIRT3 is expressed in porcine oocytes and its inhibition leads to maturation failure. This was evident through reduced polar body extrusion, arrested cell cycle, as well as disrupted spindle organization and actin distribution. Furthermore, SIRT3 inhibition resulted in a decrease in mitochondrial DNA copy numbers, disruption of mitochondrial membrane potential, and reduced ATP levels, all indicating impaired mitochondrial function in porcine oocytes. Additionally, the primary source of damaged mitochondria was associated with decreased levels of deacetylated superoxide dismutase 2 (SOD2) after SIRT3 inhibition, which led to ROS accumulation and oxidative stress-induced apoptosis. Taken together, our results suggest that SIRT3 regulates the levels of deacetylated SOD2 to maintain redox balance and preserve mitochondrial function during porcine oocyte maturation, with potential implications for improving pig reproduction.

Vitamin D3 alleviates lung fibrosis of type 2 diabetic rats via SIRT3 mediated suppression of pyroptosis

PURPOSE

We aimed to evaluate whether pulmonary fibrosis occurs in type 2 diabetes rat models and whether VD3 can prevent it by inhibiting pyroptosis.

METHODS

Sprague-Dawley rats were assigned to normal control (NC), diabetic model control (MC), low-dose VD3 (LVD), medium-dose VD3 (MVD), high-dose VD3 (HVD) and metformin positive control (PC) groups. Type 2 diabetes model was induced by a high-sugar, high-fat diet combined with STZ injection, and subsequently intervened with VD3 or metformin for 10 weeks. Blood glucose, body weight, food intake, water intake, urine volume, morphology, lung hydroxyproline level, immunohistochemistry, TUNEL staining, inflammatory cytokines secretion and related protein expression were analyzed.

RESULTS

Diabetic rats exhibited significant impairments in fasting blood glucose, insulin resistance, body weight, food intake, water intake, and urine volume. While morphological parameters, diabetic rats exhibited severe lung fibrosis. Intriguingly, VD3 intervention reversed, at least in part, the diabetes-induced alterations. The expression of pyroptosis-related proteins was up-regulated in diabetic lungs whereas the changes were reversed by VD3. In the meanwhile, SIRT3 expression was down-regulated in diabetic lungs while VD3 up-regulated it.

CONCLUSION

Fibrotic changes were observed in diabetic rat lung tissue and our study indicates that VD3 may effectively ameliorate diabetic pulmonary fibrosis via SIRT3-mediated suppression of pyroptosis.

Pathomechanisms of Diabetic Kidney Disease

The worldwide occurrence of diabetic kidney disease (DKD) is swiftly rising, primarily attributed to the growing population of individuals affected by type 2 diabetes. This surge has been transformed into a substantial global concern, placing additional strain on healthcare systems already grappling with significant demands. The pathogenesis of DKD is intricate, originating with hyperglycemia, which triggers various mechanisms and pathways: metabolic, hemodynamic, inflammatory, and fibrotic which ultimately lead to renal damage. Within each pathway, several mediators contribute to the development of renal structural and functional changes. Some of these mediators, such as inflammatory cytokines, reactive oxygen species, and transforming growth factor β are shared among the different pathways, leading to significant overlap and interaction between them. While current treatment options for DKD have shown advancement over previous strategies, their effectiveness remains somewhat constrained as patients still experience residual risk of disease progression. Therefore, a comprehensive grasp of the molecular mechanisms underlying the onset and progression of DKD is imperative for the continued creation of novel and groundbreaking therapies for this condition. In this review, we discuss the current achievements in fundamental research, with a particular emphasis on individual factors and recent developments in DKD treatment.

Non-apoptotic programmed cell deaths in diabetic pulmonary dysfunction: the new side of advanced glycation end products

Diabetes mellitus (DM) is a chronic metabolic disorder that affects multiple organs and systems, including the pulmonary system. Pulmonary dysfunction in DM patients has been observed and studied for years, but the underlying mechanisms have not been fully understood. In addition to traditional mechanisms such as the production and accumulation of advanced glycation end products (AGEs), angiopathy, tissue glycation, oxidative stress, and systemic inflammation, recent studies have focused on programmed cell deaths (PCDs), especially the non-apoptotic ones, in diabetic pulmonary dysfunction. Non-apoptotic PCDs (NAPCDs) including autophagic cell death, necroptosis, pyroptosis, ferroptosis, and copper-induced cell death have been found to have certain correlations with diabetes and relevant complications. The AGE-AGE receptor (RAGE) axis not only plays an important role in the traditional pathogenesis of diabetes lung disease but also plays an important role in non-apoptotic cell death. In this review, we summarize novel studies about the roles of non-apoptotic PCDs in diabetic pulmonary dysfunction and focus on their interactions with the AGE-RAGE axis.

Label-free optical metabolic imaging of adipose tissues for prediabetes diagnosis

Rationale: Prediabetes can be reversed through lifestyle intervention, but its main pathologic hallmark, insulin resistance (IR), cannot be detected as conveniently as blood glucose testing. In consequence, the diagnosis of prediabetes is often delayed until patients have hyperglycemia. Therefore, developing a less invasive diagnostic method for rapid IR evaluation will contribute to the prognosis of prediabetes. Adipose tissue is an endocrine organ that plays a crucial role in the development and progression of prediabetes. Label-free visualizing the prediabetic microenvironment of adipose tissues provides a less invasive alternative for the characterization of IR and inflammatory pathology. Methods: Here, we successfully identified the differentiable features of prediabetic adipose tissues by employing the metabolic imaging of three endogenous fluorophores NAD(P)H, FAD, and lipofuscin-like pigments. Results: We discovered that 1040-nm excited lipofuscin-like autofluorescence could mark the location of macrophages. This unique feature helps separate the metabolic fluorescence signals of macrophages from those of adipocytes. In prediabetes fat tissues with IR, we found only adipocytes exhibited a low redox ratio of metabolic fluorescence and high free NAD(P)H fraction a₁. This differential signature disappears for mice who quit the high-fat diet or high-fat-high-sucrose diet and recover from IR. When mice have diabetic hyperglycemia and inflamed fat tissues, both adipocytes and macrophages possess this kind of metabolic change. As confirmed with RNA-seq analysis and histopathology evidence, the change in adipocyte's metabolic fluorescence could be an indicator or risk factor of prediabetic IR. Conclusion: Our study provides an innovative approach to diagnosing prediabetes, which sheds light on the strategy for diabetes prevention.

The pathogenesis of DLD-mediated cuproptosis induced spinal cord injury and its regulation on immune microenvironment

Introduction

Spinal cord injury (SCI) is a severe central nervous system injury that leads to significant sensory and motor impairment. Copper, an essential trace element in the human body, plays a vital role in various biological functions and is strictly regulated by copper chaperones and transporters. Cuproptosis, a novel type of metal ion-induced cell death, is distinct from iron deprivation. Copper deprivation is closely associated with mitochondrial metabolism and mediated by protein fatty acid acylation.

Methods

In this study, we investigated the effects of cuproptosis-related genes (CRGs) on disease progression and the immune microenvironment in acute spinal cord injury (ASCI) patients. We obtained the gene expression profiles of peripheral blood leukocytes from ASCI patients using the Gene Expression Omnibus (GEO) database. We performed differential gene analysis, constructed protein-protein interaction networks, conducted weighted gene co-expression network analysis (WGCNA), and built a risk model.

Results

Our analysis revealed that dihydrolipoamide dehydrogenase (DLD), a regulator of copper toxicity, was significantly associated with ASCI, and DLD expression was significantly upregulated after ASCI. Furthermore, gene ontology (GO) enrichment analysis and gene set variation analysis (GSVA) showed abnormal activation of metabolism-related processes. Immune infiltration analysis indicated a significant decrease in T cell numbers in ASCI patients, while M2 macrophage numbers were significantly increased and positively correlated with DLD expression.

Discussion

In summary, our study demonstrated that DLD affects the ASCI immune microenvironment by promoting copper toxicity, leading to increased peripheral M2 macrophage polarization and systemic immunosuppression. Thus, DLD has potential as a promising biomarker for ASCI, providing a foundation for future clinical interventions.

The Role of Ketone Bodies in Various Animal Models of Kidney Disease

The kidney is a vital organ that carries out significant metabolic functions in our body. Due to the complexity of its role, the kidney is also susceptible to many disease conditions, such as acute kidney injury (AKI) and chronic kidney disease (CKD). Despite the prevalence and our increased understanding of the pathophysiology of both AKI and CKD as well as the transition of AKI to CKD, no well-established therapeutics have been applied clinically to these conditions, rendering an urgent need for a novel potential therapeutic target to be developed. In this article, we reviewed the function of ketone bodies in some common kidney conditions, such as drug-induced nephrotoxicity, ischemia and reperfusion injury, fibrosis development, diabetic kidney disease, kidney aging, hypertension, and CKD progression. All the selected studies reviewed were performed in animal models by primarily utilizing rodents, which also provide invaluable sources for future clinical applications. Ketone bodies have shown significant renal protective properties via attenuation of oxidative stress, increased expression of anti-inflammatory proteins, gene regulation, and a reduction of apoptosis of renal cells. A physiological level of ketone bodies could be achieved by fasting, a ketogenic diet, and an exogenous ketone supplement. Finally, the limitations of the long-term ketogenic diet were also discussed.

Natural Compounds with Aldose Reductase (AR) Inhibition: A Class of Medicative Agents for Fatty Liver Disease

Fatty liver disease (FLD), which includes both non-alcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (ALD), is a worldwide health concern. The etiology of ALD is long-term alcohol consumption, while NAFLD is defined as an abnormal amount of lipid present in liver cells, which is not caused by alcohol intake and has recently been identified as a hepatic manifestation of metabolic syndrome (such as type 2 diabetes, obesity, hypertension, and obesity). Inflammation, oxidative stress, and lipid metabolic dysregulation are all known to play a role in FLD progression. Alternative and natural therapies are desperately needed to treat this disease since existing pharmaceuticals are mostly ineffective. The aldose reductase (AR)/polyol pathway has recently been shown to play a role in developing FLD by contributing to inflammation, oxidative stress, apoptosis, and fat accumulation. Herein, we review the effects of plantderived compounds capable of inhibiting AR in FLD models. Natural AR inhibitors have been found to improve FLD in part by suppressing inflammation, oxidative stress, and steatosis via the regulation of several critical pathways, including the peroxisome proliferator-activated receptor (PPAR) pathway, cytochrome P450 2E1 (CYP2E1) pathway, AMP-activated protein kinase (AMPK) pathway, etc. This review revealed that natural compounds with AR inhibitory effects are a promising class of therapeutic agents for FLD.

Ameliorative effects of chickpea flavonoids on redox imbalance and mitochondrial complex I dysfunction in type 2 diabetic rats

Chickpeas are an important source of flavonoids in the human diet, and researchers have demonstrated that flavonoids have antidiabetic compositions in chickpeas. Because the NAD⁺/NADH redox balance is heavily perturbed in diabetes and complex I is the only site for NADH oxidation and NAD⁺ regeneration, in the present study, mitochondrial complex I was used as a target for anti-diabetes. The objective of this study was to investigate the effects of a crude chickpea flavonoid extract (CCFE) on NAD⁺/NADH redox imbalance and mitochondrial complex I dysfunction in the pancreas as well as oxidative stress in type 2 diabetes mellitus (T2DM) rats. Our results demonstrated that the degree of NAD⁺/NADH redox imbalance in the pancreas of T2DM rats was alleviated by CCFE, which is likely attributed to the inhibition of the polyol pathway and the decrease in poly ADP ribose polymerase (PARP) and sirtuin 3 (Sirt3) activities. Moreover, mitochondrial complex I dysfunction in the pancreas of T2DM rats was ameliorated by CCFE through the suppression of the activity of complex I. Furthermore, CCFE treatment could attenuate oxidative stress in T2DM rats, which was proven by the reduction in hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) as well as the upregulation of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in serum. CCFE treatment significantly improved dyslipidemia in T2DM rats.

Neuroprotective effects of indole-3-carbinol on the rotenone rat model of Parkinson's disease: Impact of the SIRT1-AMPK signaling pathway

Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder. Although mounting studies have been conducted, no effective therapy is available to halt its progression. Indole-3-carbinol (I3C) is a naturally occurring compound obtained by β-thioglucosidase-mediated autolysis of glucobrassicin in cruciferous vegetables. Besides its powerful antioxidant activity, I3C has shown neuroprotection against depression and chemically induced neurotoxicity via its anti-inflammatory and antiapoptotic effects. This study aimed to investigate the neuroprotective effects of I3C against rotenone (ROT)-induced PD in male albino rats. The possible protective mechanisms were also explored. PD was induced by subcutaneous administration of ROT (2 mg/kg) for 28 days. The effects of I3C (25, 50, and 100 mg/kg/day) were assessed by catalepsy test (bar test), spontaneous locomotor activity, rotarod test, weight change, tyrosine hydroxylase (TH) expression, α-synuclein (α-Syn) expression, striatal dopamine (DA) content, and histological examination. The highest dose of I3C (100 mg/kg) was the most effective to prevent ROT-mediated motor dysfunctions and amend striatal DA decrease, weight loss, neurodegeneration, TH expression reduction, and α-Syn expression increase in both the midbrain and striatum. Further mechanistic investigations revealed that the neuroprotective effects of I3C are partially attributed to its anti-inflammatory and antiapoptotic effects and the activation of the sirtuin 1/AMP-activated protein kinase pathway. Altogether, these results suggested that I3C could attenuate biochemical, molecular, and functional changes in a rat PD model with following repeated rotenone exposures.

Sorbitol accumulation decreases oocyte quality in aged mice by altering the intracellular redox balance

Sorbitol is a product of glucose metabolism through the polyol pathway. Many studies have demonstrated that excessive sorbitol can disrupt the intracellular redox balance. However, we still know very little about the impact of excessive intracellular sorbitol on oocyte quality, oocyte maturation, and embryo developmental potential. This study explored whether intracellular sorbitol accumulates in the oocytes of aged mice during in vitro maturation (IVM) and what roles sorbitol plays in oocyte development and maturation. Our results showed that sorbitol levels were significantly higher in in vitro-matured oocytes from aged mice than in oocytes from young mice (14.08 ± 3.78 vs. 0.23 ± 0.04 ng/oocyte). The expression of aldose reductase (AR) mRNA was significantly higher in the in vitro-cultured oocytes from 9-month-old mice than prior to culture. To decrease the excessive intracellular sorbitol in oocytes from aged mice, sorbinil, a specific inhibitor of aldose reductase, was supplemented in IVM medium, and the sorbitol level was significantly decreased (14.08 ± 3.78 vs. 0.48 ± 0.19 ng/oocyte). Our results indicated that the percentage of oocytes with first polar body extrusion (PBE) was significantly higher in the sorbinil group than in the aged group (82.4% ± 7.2% vs. 66.1% ± 6.9%), and the content of sorbitol was drastically increased in the aged group. The ROS fluorescence intensity in the sorbinil group was drastically lower than that in the aged group, while the GSH fluorescence intensity was significantly higher. Interestingly, SOD1 was upregulated in the sorbinil group. The present study suggests that excessive sorbitol accumulation is induced during IVM in aged mouse oocytes, which negatively influences oocyte quality by altering the intracellular redox balance. Inhibition of sorbitol accumulation may be a potential method to improve the nuclear maturation of aged oocytes.

Folic acid-induced animal model of kidney disease

The kidneys are a vital organ that is vulnerable to both acute kidney injury (AKI) and chronic kidney disease (CKD) which can be caused by numerous risk factors such as ischemia, sepsis, drug toxicity and drug overdose, exposure to heavy metals, and diabetes. In spite of the advances in our understanding of the pathogenesis of AKI and CKD as well AKI transition to CKD, there is still no available therapeutics that can be used to combat kidney disease effectively, highlighting an urgent need to further study the pathological mechanisms underlying AKI, CKD, and AKI progression to CKD. In this regard, animal models of kidney disease are indispensable. This article reviews a widely used animal model of kidney disease, which is induced by folic acid (FA). While a low dose of FA is nutritionally beneficial, a high dose of FA is very toxic to the kidneys. Following a brief description of the procedure for disease induction by FA, major mechanisms of FA-induced kidney injury are then reviewed, including oxidative stress, mitochondrial abnormalities such as impaired bioenergetics and mitophagy, ferroptosis, pyroptosis, and increased expression of fibroblast growth factor 23 (FGF23). Finally, application of this FA-induced kidney disease model as a platform for testing the efficacy of a variety of therapeutic approaches is also discussed. Given that this animal model is simple to create and is reproducible, it should remain useful for both studying the pathological mechanisms of kidney disease and identifying therapeutic targets to fight kidney disease.

Associations Between Diabetes and Idiopathic Pulmonary Fibrosis: a Study-level Pooled Analysis of 26 Million People

CONTEXT

Diabetes mellitus (DM) is a systemic disease characterized by chronic hyperglycemia associated with inflammation and oxidative stress, and the lung may be a target organ of diabetic microvascular damage. Several studies have indicated a positive association between idiopathic pulmonary fibrosis (IPF) and diabetes with controversial findings.

OBJECTIVE

Primary outcomes were to compare the prevalence of DM among individuals with IPF to non-IPF controls, and the prevalence of IPF among individuals with DM to non-DM controls.

METHODS

Data sources include PubMed, EMBASE, and the Cochrane Library. Studies contained sufficient data to calculate the prevalence of DM among individuals with and without IPF, or the prevalence of IPF among individuals with and without DM. Two investigators independently identified eligible studies and extracted data. Pooled odds ratio (OR) with 95% CI was the summary effect measure.

RESULTS

Eighteen studies including 26 410 623 individuals met the eligibility criteria, of whom 16 recruited people with IPF and 2 recruited people with DM. The OR of DM in IPF patients was 1.54 (95% CI, 1.30-1.84; P < .001) compared to that in non-IPF controls. However, compared with that in non-DM patients, the risk of IPF in DM patients was not found to be significantly reduced (OR: 0.89; 95% CI, 0.64-1.25; P = .497).

CONCLUSION

This meta-analysis suggests that people with IPF have 1.54 times increased odds of diabetes compared to non-IPF controls, while whether patients with DM have an increased risk of IPF is still controversial. Further large, prospective cohort studies investigating the prevalence of IPF in diabetic patients are warranted.

Adiponectin ameliorates lung ischemia-reperfusion injury through SIRT1-PINK1 signaling-mediated mitophagy in type 2 diabetic rats

BACKGROUND

Diabetes mellitus (DM) is a key contributing factor to poor survival in lung transplantation recipients. Mitochondrial dysfunction is recognized as a critical mediator in the pathogenesis of diabetic lung ischemia-reperfusion (IR) injury. The protective effects of adiponectin have been demonstrated in our previous study, but the underlying mechanism remains unclear. Here we demonstrated an important role of mitophagy in the protective effect of adiponectin during diabetic lung IR injury.

METHODS

High-fat diet-fed streptozotocin-induced type 2 diabetic rats were exposed to adiponectin with or without administration of the SIRT1 inhibitor EX527 following lung transplantation. To determine the mechanisms underlying the action of adiponectin, rat pulmonary microvascular endothelial cells were transfected with SIRT1 small-interfering RNA or PINK1 small-interfering RNA and then subjected to in vitro diabetic lung IR injury.

RESULTS

Mitophagy was impaired in diabetic lungs subjected to IR injury, which was accompanied by increased oxidative stress, inflammation, apoptosis, and mitochondrial dysfunction. Adiponectin induced mitophagy and attenuated subsequent diabetic lung IR injury by improving lung functional recovery, suppressing oxidative damage, diminishing inflammation, decreasing cell apoptosis, and preserving mitochondrial function. However, either administration of 3-methyladenine (3-MA), an autophagy antagonist or knockdown of PINK1 reduced the protective action of adiponectin. Furthermore, we demonstrated that APN affected PINK1 stabilization via the SIRT1 signaling pathway, and knockdown of SIRT1 suppressed PINK1 expression and compromised the protective effect of adiponectin.

CONCLUSION

These data demonstrated that adiponectin attenuated reperfusion-induced oxidative stress, inflammation, apoptosis and mitochondrial dysfunction via activation of SIRT1- PINK1 signaling-mediated mitophagy in diabetic lung IR injury.

Curcumin nano-micelle induced testicular toxicity in healthy rats; evidence for oxidative stress and failed homeostatic response by heat shock proteins 70-2a and 90

This study explores the effect of curcumin nano-micelle (NCMN) on the testicular anti-oxidant status and heat shock proteins (Hsp) 70-2a and Hsp 90 expression. Therefore, 24 male Wistar rats were divided into control, 7.50 mg/kg, 15 mg/kg, and 30 mg/kg of NCMN-received groups. Following 48 days, the testicular total anti-oxidant capacity (TAC), total oxidant status (TOS), malondialdehyde (MDA) and glutathione (GSH), catalase (CAT) and glutathione peroxidase (GPX) activities, immunoreactivity of 8-oxodG, Hsp70-2a and Hsp90 expressions, germ cell's DNA and mRNA damages, the spermatozoa count, motility and DNA integrity were assessed. With no change in the testicular TAC level, the TOS, MDA and GSH contents were increased in the NMC-received groups. However, CAT and GPX activities were decreased. The NCMN suppressed spermatogenesis, increased immunoreactivity of 8-oxodG, stimulated the Hsp70-2a and Hsp90 expressions, and resulted in severe DNA and mRNA damages. Moreover, the NCMN-received animals exhibited remarkable reductions in the spermatozoa count, motility and DNA integrity. In conclusion, chronic and high dose consumption of NCMN initiates OS, and in response to OS, the Hsp70-2a and Hsp90 expression increases. However, considering enhanced DNA and mRNA damages and suppressed spermatogenesis, HSPs over-expression can neither boost the anti-oxidant system nor overcome the NCMN-induced OS-related damages.

PARPs in lipid metabolism and related diseases

PARPs and tankyrases (TNKS) represent a family of 17 proteins. PARPs and tankyrases were originally identified as DNA repair factors, nevertheless, recent advances have shed light on their role in lipid metabolism. To date, PARP1, PARP2, PARP3, tankyrases, PARP9, PARP10, PARP14 were reported to have multi-pronged connections to lipid metabolism. The activity of PARP enzymes is fine-tuned by a set of cholesterol-based compounds as oxidized cholesterol derivatives, steroid hormones or bile acids. In turn, PARPs modulate several key processes of lipid homeostasis (lipotoxicity, fatty acid and steroid biosynthesis, lipoprotein homeostasis, fatty acid oxidation, etc.). PARPs are also cofactors of lipid-responsive nuclear receptors and transcription factors through which PARPs regulate lipid metabolism and lipid homeostasis. PARP activation often represents a disruptive signal to (lipid) metabolism, and PARP-dependent changes to lipid metabolism have pathophysiological role in the development of hyperlipidemia, obesity, alcoholic and non-alcoholic fatty liver disease, type II diabetes and its complications, atherosclerosis, cardiovascular aging and skin pathologies, just to name a few. In this synopsis we will review the evidence supporting the beneficial effects of pharmacological PARP inhibitors in these diseases/pathologies and propose repurposing PARP inhibitors already available for the treatment of various malignancies.

Potential Impact of Diabetes and Obesity on Alveolar Type 2 (AT2)-Lipofibroblast (LIF) Interactions After COVID-19 Infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a new emerging respiratory virus, caused evolving pneumonia outbreak around the world. In SARS-Cov-2 infected patients, diabetes mellitus (DM) and obesity are two metabolic diseases associated with higher severity of SARS-CoV-2 related complications, characterized by acute lung injury requiring assisted ventilation as well as fibrosis development in surviving patients. Different factors are potentially responsible for this exacerbated response to SARS-CoV-2 infection. In patients with DM, base-line increase in inflammation and oxidative stress represent preexisting risk factors for virus-induced damages. Such factors are also likely to be found in obese patients. In addition, it has been proposed that massive injury to the alveolar epithelial type 2 (AT2) cells, which express the SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE2), leads to the activation of their stromal niches represented by the Lipofibroblasts (LIF). LIF are instrumental in maintaining the self-renewal of AT2 stem cells. LIF have been proposed to transdifferentiate into Myofibroblast (MYF) following injury to AT2 cells, thereby contributing to fibrosis. We hypothesized that LIF's activity could be impacted by DM or obesity in an age- and gender-dependent manner, rendering them more prone to transition toward the profibrotic MYF status in the context of severe COVID-19 pneumonia. Understanding the cumulative effects of DM and/or obesity in the context of SARS-CoV-2 infection at the cellular level will be crucial for efficient therapeutic solutions.

Identification of bioactive metabolites in human iPSC-derived dopaminergic neurons with PARK2 mutation: Altered mitochondrial and energy metabolism

PARK2 (parkin) mutations cause early-onset Parkinson's disease (PD). Parkin is an ubiquitin E3 ligase that participates in several cellular functions, including mitochondrial homeostasis. However, the specific metabolomic changes caused by parkin depletion remain unknown. Here, we used isogenic human induced pluripotent stem cells (iPSCs) with and without PARK2 knockout (KO) to investigate the effect of parkin loss of function by comparative metabolomics supplemented with ultrastructural and functional analyses. PARK2 KO neurons displayed increased tricarboxylic acid (TCA) cycle activity, perturbed mitochondrial ultrastructure, ATP depletion, and dysregulation of glycolysis and carnitine metabolism. These perturbations were combined with increased oxidative stress and a decreased anti-oxidative response. Key findings for PARK2 KO cells were confirmed using patient-specific iPSC-derived neurons. Overall, our data describe a unique metabolomic profile associated with parkin dysfunction and show that combining metabolomics with an iPSC-derived dopaminergic neuronal model of PD is a valuable approach to obtain novel insight into the disease pathogenesis.

NADH/NAD+ Redox Imbalance and Diabetic Kidney Disease

Diabetic kidney disease (DKD) is a common and severe complication of diabetes mellitus. If left untreated, DKD can advance to end stage renal disease that requires either dialysis or kidney replacement. While numerous mechanisms underlie the pathogenesis of DKD, oxidative stress driven by NADH/NAD⁺ redox imbalance and mitochondrial dysfunction have been thought to be the major pathophysiological mechanism of DKD. In this review, the pathways that increase NADH generation and those that decrease NAD⁺ levels are overviewed. This is followed by discussion of the consequences of NADH/NAD⁺ redox imbalance including disruption of mitochondrial homeostasis and function. Approaches that can be applied to counteract DKD are then discussed, which include mitochondria-targeted antioxidants and mimetics of superoxide dismutase, caloric restriction, plant/herbal extracts or their isolated compounds. Finally, the review ends by pointing out that future studies are needed to dissect the role of each pathway involved in NADH-NAD⁺ metabolism so that novel strategies to restore NADH/NAD⁺ redox balance in the diabetic kidney could be designed to combat DKD.

Gut-Lung Dysbiosis Accompanied by Diabetes Mellitus Leads to Pulmonary Fibrotic Change through the NF-κB Signaling Pathway

Growing evidence shows that the lungs are an unavoidable target organ of diabetic complications. However, the pathologic mechanisms of diabetic lung injury are still controversial. This study demonstrated the dysbiosis of the gut and lung microbiome, pulmonary alveolar wall thickening, and fibrotic change in streptozotocin-induced diabetic mice and antibiotic-induced gut dysbiosis mice compared with controls. In both animal models, the NF-κB signaling pathway was activated in the lungs. Enhanced pulmonary alveolar well thickening and fibrotic change appeared in the lungs of transgenic mice expressing a constitutively active NF-κB mutant compared with wild type. When lincomycin hydrochloride-induced gut dysbiosis was ameliorated by fecal microbiota transplant, enhanced inflammatory response in the intestine and pulmonary fibrotic change in the lungs were significantly decreased compared with lincomycin hydrochloride-treated mice. Furthermore, the application of fecal microbiota transplant and baicalin could also redress the microbial dysbiosis of the gut and lungs in streptozotocin-induced diabetic mice. Taken together, these data suggest that multiple as yet undefined factors related to microbial dysbiosis of gut and lungs cause pulmonary fibrogenesis associated with diabetes mellitus through an NF-κB signaling pathway.

A requirement for PAK1 to support mitochondrial function and maintain cellular redox balance via electron transport chain proteins to prevent β-cell apoptosis

OBJECTIVE

p21 (Cdc42/Rac1) activated Kinase 1 (PAK1) is a candidate susceptibility factor for type 2 diabetes (T2D). PAK1 is depleted in the islets from T2D donors, compared to control individuals. In addition, whole-body PAK1 knock out (PAK1-KO) in mice worsens the T2D-like effects of high-fat diet. The current study tested the effects of modulating PAK1 levels only in β-cells.

MATERIALS/METHODS

β-cell-specific inducible PAK1 KO (βPAK1-iKO) mice were generated and used with human β-cells and T2D islets to evaluate β-cell function.

RESULTS

βPAK1-iKO mice exhibited glucose intolerance and elevated β-cell apoptosis, but without peripheral insulin resistance. β-cells from βPAK-iKO mice also contained fewer mitochondria per cell. At the cellular level, human PAK1-deficient β-cells showed blunted glucose-stimulated insulin secretion and reduced mitochondrial function. Mitochondria from human PAK1-deficient β-cells were deficient in the electron transport chain (ETC) subunits CI, CIII, and CIV; NDUFA12, a CI complex protein, was identified as a novel PAK1 binding partner, and was significantly reduced with PAK1 knockdown. PAK1 knockdown disrupted the NAD+/NADH and NADP+/NADPH ratios, and elevated ROS. An imbalance of the redox state due to mitochondrial dysfunction leads to ER stress in β-cells. PAK1 replenishment in the β-cells of T2D human islets ameliorated levels of ER stress markers.

CONCLUSIONS

These findings support a protective function for PAK1 in β-cells. The results support a new model whereby the PAK1 in the β-cell plays a required role upstream of mitochondrial function, via maintaining ETC protein levels and averting stress-induced β-cell apoptosis to retain healthy functional β-cell mass.

The Diabetic Lung: Insights into Pulmonary Changes in Children and Adolescents with Type 1 Diabetes

Historically, the lung was not listed and recognized as a major target organ of diabetic injury. The first evidence of diabetic lung involvement was published fifty years ago, with a study conducted in a population of young adults affected by type 1 diabetes (T1D). In recent years, there has been mounting evidence showing that the lung is a target organ of diabetic injury since the beginning of the disease—at the pediatric age. The deeply branched vascularization of the lungs and the abundance of connective tissue, indeed, make them vulnerable to the effects of hyperglycemia, in a way similar to other organs affected by microvascular complications. In this review, we focus on pulmonary function impairment in children and adolescents affected by T1D. We also cover controversial aspects regarding available studies and future perspectives in this field.

Free serum sorbitol and its interaction with caffeine: A suggestive approach for plausible remediation of diabetic neuropathy

The measure of sorbitol in serum can act as a good indicator in the monitoring of the diabetic complications. To analyze the sorbitol level in serum medium, fluorometric enzymatic assay was performed. To remove the excess sorbitol from the body, proposed binding of sorbitol with caffeine was investigated. Their interaction in serum medium was studied and established by UV-Vis, fluorescence spectrophotometry, and time-correlated single photon counting (TCSPC). The linear calibration of sorbitol (in the range 10-50 mM) was done using UV-Vis spectrophotometry. Time scan experiments furnished the reaction rate of sorbitol assayed solution as well as sorbitol-caffeine complex as 0.021 min^-1 and 0.018 min^-1 , respectively. A sudden drop was observed in the fluorescence lifetime of reduced nicotinamide adenine dinucleotide (NADH) present in sorbitol assayed solution upon complexation with caffeine, that is, from 1.774 × 10^-09 to 1.23 × 10^-10 Sec, which indicates the hindrance in the formation of NADH and the probable formation of some other species. Isothermal titration calorimetric experiments clearly indicate the number of binding sites (i.e., 3.89, 1.40, and 2.07) that exist between sorbitol and caffeine at the complexation ratio of 1:1.2, 1:1.5, and 1:3. The present method can be helpful in pharmacological and therapeutic studies of sorbitol using caffeine for treating diabetic neuropathy.

Senescence in Pulmonary Fibrosis: Between Aging and Exposure

To date, chronic pulmonary pathologies represent the third leading cause of death in the elderly population. Evidence-based projections suggest that >65 (years old) individuals will account for approximately a quarter of the world population before the turn of the century. Genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication, are described as the nine “hallmarks” that govern cellular fitness. Any deviation from the normal pattern initiates a complex cascade of events culminating to a disease state. This blueprint, originally employed to describe aberrant changes in cancer cells, can be also used to describe aging and fibrosis. Pulmonary fibrosis (PF) is the result of a progressive decline in injury resolution processes stemming from endogenous (physiological decline or somatic mutations) or exogenous stress. Environmental, dietary or occupational exposure accelerates the pathogenesis of a senescent phenotype based on (1) window of exposure; (2) dose, duration, recurrence; and (3) cells type being targeted. As the lung ages, the threshold to generate an irreversibly senescent phenotype is lowered. However, we do not have sufficient knowledge to make accurate predictions. In this review, we provide an assessment of the literature that interrogates lung epithelial, mesenchymal, and immune senescence at the intersection of aging, environmental exposure and pulmonary fibrosis.

Hydrogen Sulfide Ameliorates Lung Ischemia-Reperfusion Injury Through SIRT1 Signaling Pathway in Type 2 Diabetic Rats

Lung ischemia-reperfusion (IR) injury remains a significant factor for the early mortality of lung transplantations. Diabetes mellitus (DM) is an independent risk factor for 5-year mortality following lung transplantation. Our previous study showed that DM aggravated lung IR injury and that oxidative stress played a key role in this process. Previously, we demonstrated that hydrogen sulfide (H₂S) protected against diabetic lung IR injury by suppressing oxidative damage. This study aimed to examine the mechanism by which H₂S affects diabetic lung IR injury. High-fat-diet-fed streptozotocin-induced type 2 diabetic rats were exposed to GYY4137, a slow-releasing H₂S donor with or without administration of EX527 (a SIRT1 inhibitor), and then subjected to a surgical model of IR injury of the lung. Lung function, oxidative stress, cell apoptosis, and inflammation were assessed. We found that impairment of lung SIRT1 signaling under type 2 diabetic conditions was further exacerbated by IR injury. GYY4137 treatment markedly activated SIRT1 signaling and ameliorated lung IR injury in type 2 DM animals by improving lung functional recovery, diminishing oxidative damage, reducing inflammation, and suppressing cell apoptosis. However, these effects were largely compromised by EX527. Additionally, treatment with GYY4137 significantly activated the Nrf2/HO-1 antioxidant signaling pathway and increased eNOS phosphorylation. However, these effects were largely abolished by EX527. Together, our results indicate that GYY4137 treatment effectively attenuated lung IR injury under type 2 diabetic conditions via activation of lung SIRT1 signaling. SIRT1 activation upregulated Nrf2/HO-1 and activated the eNOS-mediated antioxidant signaling pathway, thus reducing cell apoptosis and inflammation and eventually preserving lung function.

Metabolic Responses to Reductive Stress

Significance: Reducing equivalents (NAD(P)H and glutathione [GSH]) are essential for maintaining cellular redox homeostasis and for modulating cellular metabolism. Reductive stress induced by excessive levels of reduced NAD⁺ (NADH), reduced NADP⁺ (NADPH), and GSH is as harmful as oxidative stress and is implicated in many pathological processes. Recent Advances: Reductive stress broadens our view of the importance of cellular redox homeostasis and the influences of an imbalanced redox niche on biological functions, including cell metabolism. Critical Issues: The distribution of cellular NAD(H), NADP(H), and GSH/GSH disulfide is highly compartmentalized. Understanding how cells coordinate different pools of redox couples under unstressed and stressed conditions is critical for a comprehensive view of redox homeostasis and stress. It is also critical to explore the underlying mechanisms of reductive stress and its biological consequences, including effects on energy metabolism. Future Directions: Future studies are needed to investigate how reductive stress affects cell metabolism and how cells adapt their metabolism to reductive stress. Whether or not NADH shuttles and mitochondrial nicotinamide nucleotide transhydrogenase enzyme can regulate hypoxia-induced reductive stress is also a worthy pursuit. Developing strategies (e.g., antireductant approaches) to counteract reductive stress and its related adverse biological consequences also requires extensive future efforts.

Mesenchymal Stem Cells Attenuate Diabetic Lung Fibrosis via Adjusting Sirt3-Mediated Stress Responses in Rats

Diabetes affects a variety of organs such as the kidneys, eyes, and liver, and there is increasing evidence that the lung is also one of the target organs of diabetes and imbalance of Sirt3-mediated stress responses such as inflammation, oxidative stress, apoptosis, autophagy, and ER stress may contribute to diabetic lung fibrosis. Although previous studies have reported that mesenchymal stem cells (MSCs) have beneficial effects on various diabetic complications, the effect and mechanisms of MSCs on diabetes-induced lung injury are not clear. In this study, the STZ-induced diabetes model was constructed in rats, and the effect and potential mechanisms of bone marrow MSCs on diabetic lung fibrosis were investigated. The results revealed that fibrotic changes in the lung were successfully induced in the diabetic rats, while MSCs significantly inhibited or even reversed the changes. Specifically, MSCs upregulated the expression levels of Sirt3 and SOD2 and then activated the Nrf2/ARE signaling pathway, thereby controlling MDA, GSH content, and iNOS and NADPH oxidase subunit p22phox expression levels in the lung tissue. Meanwhile, high levels of Sirt3 and SOD2 induced by MSCs reduced the expression levels of IL-1β, TNF-α, ICAM-1, and MMP9 by suppressing the NF-κB/HMGB1/NLRP3/caspase-1 signaling pathway, as well as regulating the expression levels of cleaved caspasese-3, Bax, and Bcl2 by upregulating the expression level of P-Akt, thereby inhibiting the apoptosis of the lung tissue. In addition, MSCs also regulated the expression levels of LC3, P62, BiP, Chop, and PERK, thereby enhancing autophagy and attenuating endoplasmic reticulum stress. Taken together, our results suggest that MSCs effectively attenuate diabetic lung fibrosis via adjusting Sirt3-mediated responses, including inflammation, oxidative stress, apoptosis, autophagy, and endoplasmic reticulum stress, providing a theoretical foundation for further exploration of MSC-based diabetic therapeutics.

Circadian Clock and Sirtuins in Diabetic Lung: A Mechanistic Perspective

Diabetes-induced tissue injuries in target organs such as the kidney, heart, eye, liver, skin, and nervous system contribute significantly to the morbidity and mortality of diabetes. However, whether the lung should be considered a diabetic target organ has been discussed for decades. Accumulating evidence shows that both pulmonary histological changes and functional abnormalities have been observed in diabetic patients, suggesting that the lung is a diabetic target organ. Mechanisms underlying diabetic lung are unclear, however, oxidative stress, systemic inflammation, and premature aging convincingly contribute to them. Circadian system and Sirtuins have been well-documented to play important roles in above mechanisms. Circadian rhythms are intrinsic mammalian biological oscillations with a period of near 24 h driven by the circadian clock system. This system plays an important role in the regulation of energy metabolism, oxidative stress, inflammation, cellular proliferation and senescence, thus impacting metabolism-related diseases, chronic airway diseases and cancers. Sirtuins, a family of adenine dinucleotide (NAD⁺)-dependent histone deacetylases, have been demonstrated to regulate a series of physiological processes and affect diseases such as obesity, insulin resistance, type 2 diabetes (T2DM), heart disease, cancer, and aging. In this review, we summarize recent advances in the understanding of the roles of the circadian clock and Sirtuins in regulating cellular processes and highlight the potential interactions of the circadian clock and Sirtuins in the context of diabetic lung.

Reductive Stress-Induced Mitochondrial Dysfunction and Cardiomyopathy

The goal of this review was to summarize reported studies focusing on cellular reductive stress-induced mitochondrial dysfunction, cardiomyopathy, dithiothreitol- (DTT-) induced reductive stress, and reductive stress-related free radical reactions published in the past five years. Reductive stress is considered to be a double-edged sword in terms of antioxidation and disease induction. As many underlying mechanisms are still unclear, further investigations are obviously warranted. Nonetheless, reductive stress is thought to be caused by elevated levels of cellular reducing power such as NADH, glutathione, and NADPH; and this area of research has attracted increasing attention lately. Albeit, we think there is a need to conduct further studies in identifying more indicators of the risk assessment and prevention of developing heart damage as well as exploring more targets for cardiomyopathy treatment. Hence, it is expected that further investigation of underlying mechanisms of reductive stress-induced mitochondrial dysfunction will provide novel insights into therapeutic approaches for ameliorating reductive stress-induced cardiomyopathy.

Antioxidative and Hypoglycemic Effect of Ta-ermi Extracts on Streptozotocin-Induced Diabetes

INTRODUCTION

The purpose of the present study was to reveal the potential positive effect of the Ta-ermi extracts on oxidative stress and streptozotocin (STZ)-diabetic mice and rats treated with Ta-ermi water- and alcohol-extracts.

METHODS

The study was carried out using three experimental model: 1) in vitro experiments whereby Ta-ermi extracts were incubated with free radical generators such as 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) to evaluate Ta-ermi's antioxidant effects; 2) testing the hypoglycemic effects of Ta-ermi extracts in streptozotocin (STZ)-induced diabetic mice; and 3) testing the beneficial effects of Ta-ermi extracts on mitochondrial complex I function using STZ-diabetic rats.

RESULTS

In vitro antioxidant experiments showed that both of the extracts could scavenge free radicals and exhibited inhibitory effects on glucosidase and aldose reductase with differential effects between water extract and alcohol extract. In the STZ mouse diabetic model, both the water- and alcohol-extracts attenuated body weight decrease, decreased blood glucose levels in a concentration-dependent manner, improved insulin sensitivity, and increased oral glucose tolerance ability. In the STZ-diabetic rat model, both the water- and alcohol-extracts were found to be able to lower blood glucose levels in the diabetic animals with no effects on body weight changes. Moreover, in the STZ-diabetic rats, both the water- and alcohol-extracts of Ta-ermi could inhibit the increase of mitochondrial NADH/ubiquinone oxidoreductase (complex I) activity in the pancreas and enhanced complex I activity in the liver but showed no effect on lung or kidney mitochondrial complex I.

DISCUSSION

The present study points to the potential medicinal value of Ta-ermi's water and alcohol extracts in lowering blood glucose and decreasing diabetic oxidative stress. One limitation of our study is that the compound or compounds that actually have this beneficial effect in the extracts remain unknown at this time. Therefore, the future studies should be focused on the identification of the components in the extracts that exhibit anti-oxidative and hypoglycemic effects.

CONCLUSION

Taken together, our studies using different experimental paradigms indicate that Ta-ermi extracts possess antioxidant and anti-diabetic properties and may be employed as functional food ingredients for the remission of diabetes.

Neuroprotection of Cyperus esculentus L. orientin against cerebral ischemia/reperfusion induced brain injury

Orientin is a flavonoid monomer. In recent years, its importance as a source of pharmacological active substance is growing rapidly due to its properties such as anti-myocardial ischemia, anti-apoptosis, anti-radiation, anti-tumor, and anti-aging. However, the neuroprotective effects of Orientin on stroke injury have not been comprehensively evaluated. The aim of the present study was thus to investigate the neuroprotective capacity and the potential mechanisms of Cyperus esculentus L. orientin (CLO) from Cyperus esculentus L. leaves against ischemia/reperfusion (I/R) injury using standard orientin as control. For in vitro studies, we treated HT22 cells with CoCl₂ as an in vitro ischemic injury model. HT22 cells in the control group were treated with CoCl₂. For in vivo studies, we used rat models of middle cerebral artery occlusion, and animals that received sham surgery were used as controls. We found that CLO protected CoCl₂-induced HT22 cells against ischemia/reperfusion injury by lowering lipid peroxidation and reactive oxygen species formation as well as decreasing protein oxidation. However, CLO did not reduce the release of lactate dehydrogenase nor increase the activity of superoxide dismutase. Results showed that CLO could decrease neurological deficit score, attenuate brain water content, and reduce cerebral infarct volume, leading to neuroprotection during cerebral ischemia-reperfusion injury. Our studies indicate that CLO flavonoids can be taken as a natural antioxidant and bacteriostastic substance in food and pharmaceutical industry. The molecular mechanisms of CLO could be at least partially attributed to the antioxidant properties and subsequently inhibiting activation of casepase-3. All experimental procedures and protocols were approved on May 16, 2016 by the Experimental Animal Ethics Committee of Xinjiang Medical University of China (approval No. IACUC20160516-57).

Protective effects of β- nicotinamide adenine dinucleotide against motor deficits and dopaminergic neuronal damage in a mouse model of Parkinson's disease

The level of nicotinamide adenine dinucleotide (NAD) decreases in Parkinson's disease (PD), and its reduction has been reported to be involved in many age-associated neurodegenerative pathologies. Thus, we investigated whether NAD replenishment is beneficial in a 6-hydroxydopamine (6-OHDA)-induced mouse model of PD. Preinjection with NAD in the striatum ameliorated motor deficits and dopaminergic neuronal damage in the substantia nigra and striatum of a mouse model of PD. Moreover, preincubation with NAD protected PC12 cells against the loss of cell viability, morphological damage, oxidative stress and mitochondrial dysfunction caused by 6-OHDA. These results add credence to the beneficial role of NAD against parkinsonian neurodegeneration in mouse models of PD, provide evidence for the potential of NAD for the prevention of PD, and suggest that NAD prevents pathological changes in PD via decreasing mitochondrial dysfunctions.

D-ribose is elevated in T1DM patients and can be involved in the onset of encephalopathy

Although many mechanisms have been proposed for diabetic encephalopathy in type 2 diabetes mellitus (T2DM), the risk factors for cognitive impairment in type 1 diabetes mellitus (T1DM) are less clear. Here, we show that streptozotocin (STZ)-induced T1DM rats showed cognitive impairment in both Y maze and Morris water maze assays, accompanied with D-ribose was significantly increased in blood and urine, in addition to D-glucose. Furthermore, advanced glycation end products (AGE), Tau hyperphosphorylation and neuronal death in the hippocampal CA4/DG region were detected in T1DM rats. The expression and activity of transketolase (TKT), an important enzyme in the pentose shunt, were decreased in the brain, indicating that TKT may be involved in D-ribose metabolism in T1DM. Support for these change was demonstrated by the activation of TKT with benfotiamine (BTMP) treatment. Decreased D-ribose levels but not D-glucose levels; markedly reduced AGE accumulation, Tau hyperphosphorylation, and neuronal death; and improved cognitive ability in T1DM rats were shown after BTMP administration. In clinical investigation, T1DM patients had high D-ribose levels in both urine and serum. Our work suggests that D-ribose is involved in the cognitive impairment in T1DM and may provide a potentially novel target for treating diabetic encephalopathy.

Impact of Donor Diabetes on Outcomes of Lung Transplantation in the United States

BACKGROUND

Diabetes mellitus is among several factors considered when assessing the suitability of donated organs for transplantation. Lungs from diabetic donors (LDD) are not contraindicated for use as allografts, despite established evidence of diabetes-mediated parenchymal damage. The present study used a national database to assess the impact of donor diabetes on the longevity of lung transplant recipients.

METHODS

This retrospective study of the United Network for Organ Sharing database analyzed all adult lung transplant recipients from June 2005 through September 2016. Donor and recipient demographics including the presence of diabetes were used to create a multivariable model. The primary outcome was 5-y mortality, with hazard ratios (HRs) assessed using multivariable Cox regression analysis. Survival curves were calculated using the Kaplan-Meier method.

RESULTS

Of the 17,839 lung transplant recipients analyzed, 1203 (6.7%) received LDD. Recipients of LDD were more likely to be female (44.1% versus 40.2%, P < 0.01) and have mismatched race (47.5% versus 42.2%, P < 0.01). Diabetic donors were more likely to have hypertension (74.6% versus 19.0%, P < 0.01). Multivariable analysis revealed LDD to be an independent predictor of mortality at 5 y (HR 1.16 [1.04-1.29], P < 0.01). However, among the subgroup of diabetic recipients, transplantation of LDD showed no independent association with 5-y mortality (HR 0.81 [0.63-1.06], P = 0.12).

CONCLUSIONS

Recipients of LDD had a lower 5-y post lung transplantation survival compared with recipients of lungs from nondiabetic donors. LDD allografts did not influence the survival of diabetic recipients.

Role of pseudohypoxia in the pathogenesis of type 2 diabetes

Type 2 diabetes is caused by persistent high blood glucose, which is known as diabetic hyperglycemia. This hyperglycemic situation, when not controlled, can overproduce NADH and lower nicotinamide adenine dinucleotide (NAD), thereby creating NADH/NAD redox imbalance and leading to cellular pseudohypoxia. In this review, we discussed two major enzymatic systems that are activated by diabetic hyperglycemia and are involved in creation of this pseudohypoxic condition. One system is aldose reductase in the polyol pathway, and the other is poly (ADP ribose) polymerase. While aldose reductase drives overproduction of NADH, PARP could in contrast deplete NAD. Therefore, activation of the two pathways underlies the major mechanisms of NADH/NAD redox imbalance and diabetic pseudohypoxia. Consequently, reductive stress occurs, followed by oxidative stress and eventual cell death and tissue dysfunction. Additionally, fructose formed in the polyol pathway can also cause metabolic syndrome such as hypertension and nonalcoholic fatty liver disease. Moreover, pseudohypoxia can also lower sirtuin protein contents and induce protein acetylation which can impair protein function. Finally, we discussed the possibility of using nicotinamide riboside, an NAD precursor, as a promising therapeutic agent for restoring NADH/NAD redox balance and for preventing the occurrence of diabetic pseudohypoxia.

Sorbinil, an Aldose Reductase Inhibitor, in Fighting Against Diabetic Complications

BACKGROUND

Aldose reductase (AR) is involved in the pathogenesis of diabetes, which is one of the major threats to global public health.

OBJECTIVE

In this review article, we have discussed the role of sorbinil, an AR inhibitor (ARI), in preventing diabetic complications.

RESULTS

AR contributes in diabetes by generating excess intracellular superoxide and other mediators of oxidative stress through polyol pathway. Inhibition of AR activity thus might be a potential approach for the management of diabetic complications. Experimental evidences indicated that sorbinil can decrease AR activity and inhibit polyol pathway. Both in vitro and animal model studies reported the efficacy of sorbinil in controlling the progression of diabetes. Moreover, Sorbinil has been found to be comparatively safer than other ARIs for human use. But, it is still in earlyphase testing for the treatment of diabetic complications clinically.

CONCLUSION

Sorbinil is an effective ARI, which could play therapeutic role in treating diabetes and diabetic complications. However, advanced clinical trials are required for sorbinil so that it could be applied with the lowest efficacious dose in humans.

Hydrogen sulfide attenuates lung ischemia-reperfusion injury through SIRT3-dependent regulation of mitochondrial function in type 2 diabetic rats

BACKGROUND

Lung ischemia-reperfusion injury is a complex pathophysiologic process associated with high morbidity and mortality. We have demonstrated elsewhere that diabetes mellitus aggravated ischemia-induced lung injury. Oxidative stress and mitochondrial dysfunction are drivers of diabetic lung ischemia-reperfusion injury; however, the pathways that mediate these events are unexplored. In this study using a high-fat diet-fed model of streptozotocin-induced type 2 diabetes in rats, we determined the effect of hydrogen sulfide on lung ischemia-reperfusion injury with a focus on Sirtuin3 signaling.

METHODS

Rats with type 2 diabetes were exposed to GYY4137, a slow release donor of hydrogen sulfide with or without administration of the Sirtuin3 short hairpin ribonucleic acid plasmid, and then subjected to a surgical model of ischemia-reperfusion injury of the lung (n = 8). Lung function, oxidative stress, inflammation, cell apoptosis, and mitochondrial function were measured.

RESULTS

Compared with nondiabetic rats, animals with type 2 diabetes at baseline exhibited significantly decreased Sirtuin3 signaling in lung tissue and increased oxidative stress, apoptosis, inflammation, and mitochondrial dysfunction (P < .05 each). In addition, further impairment in Sirtuin3 signaling was found in diabetic rats subjected to this model of lung ischemia-reperfusion. Simultaneously, the indexes showed further aggravation. Treatment with hydrogen sulfide restored Sirtuin3 expression and decreased lung ischemia-reperfusion injury in animals with type 2 diabetes mellitus by improving lung functional recovery, decreasing oxidative damage, suppressing inflammation, ameliorating cell apoptosis, and preserving mitochondrial function (P < .05). Conversely, these protective effects were largely reversed in Sirtuin3 knockdown rats.

CONCLUSION

Impaired lung Sirtuin3 signaling associated with type 2 diabetic conditions was further attenuated by an ischemia-reperfusion insult. Hydrogen sulfide ameliorated reperfusion-induced oxidative stress and mitochondrial dysfunction via activation of Sirtuin3 signaling, thereby decreasing lung ischemia-reperfusion damage in rats with a model of type II diabetes.

Chronic Inhibition of Mitochondrial Dihydrolipoamide Dehydrogenase (DLDH) as an Approach to Managing Diabetic Oxidative Stress

Mitochondrial dihydrolipoamide dehydrogenase (DLDH) is a redox enzyme involved in decarboxylation of pyruvate to form acetyl-CoA during the cascade of glucose metabolism and mitochondrial adenine triphosphate (ATP) production. Depending on physiological or pathophysiological conditions, DLDH can either enhance or attenuate the production of reactive oxygen species (ROS) and reactive nitrogen species. Recent research in our laboratory has demonstrated that inhibition of DLDH induced antioxidative responses and could serve as a protective approach against oxidative stress in stroke injury. In this perspective article, we postulated that chronic inhibition of DLDH could also attenuate oxidative stress in type 2 diabetes. We discussed DLDH-involving mitochondrial metabolic pathways and metabolic intermediates that could accumulate upon DLDH inhibition and their corresponding roles in abrogating oxidative stress in diabetes. We also discussed a couple of DLDH inhibitors that could be tested in animal models of type 2 diabetes. It is our belief that DLDH inhibition could be a novel approach to fighting type 2 diabetes.