Impaired Folate-Mediated One-Carbon Metabolism in Type 2 Diabetes, Late-Onset Alzheimer's Disease and Long COVID

Assessment of the Concentrations of Selected Aminothiols in Patients after COVID-19

Background: Data show that due to endothelial damage and thrombogenic effects, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection may accelerate the development of atherosclerosis and increase the risk of cardiovascular diseases (CVDs). The impaired metabolism of aminothiols increases oxidative stress, as these molecules are involved in antioxidant defense as well as in thiol redox control. In this study, total levels of selected aminothiols (i.e., cysteine (Cys), homocysteine (HCy), and glutathione) in convalescents after coronavirus disease of 2019 (COVID-19) were evaluated. The analyses were made according to the sex of the patients, time from COVID-19 onset, and COVID-19 severity. Methods: The study group consisted of 212 patients after COVID-19. Levels of total aminothiols were assessed in the blood plasma using high-performance liquid chromatography (HPLC). Results: The mean Cys concentrations were higher in men than in women (229.92 µmol/L ± 51.54 vs. 210.35 µmol/L ± 41.90, respectively; p = 0.003). Differences in Cys levels were also noticed in the total study group between patients distinguished due to time from disease onset (226.82 µmol/L ± 40.57 in <12 weeks, 232.23 µmol/L ± 47.99 in patients 12-24 weeks, and 208.08 µmol/L ± 48.43 in patients >24 weeks; p = 0.005). In addition, over 11% of total patients 12-24 weeks from disease onset had Cys levels above 300 µmol/L compared to almost 4% of patients <12 weeks and 2% of patients >24 weeks (p = 0.046). In sex-adjusted subgroups, significant differences due to time from COVID-19 were found in Cys levels in women (p = 0.004) and in glutathione levels in men (p = 0.024). None of the aminothiol levels differed between the subgroups based on the severity of COVID-19. Conclusions: Men had overall higher Cys levels than women. Cys levels were lower >24 weeks after COVID-19 onset than in the earlier period after disease onset. A partial elevation in Cys levels 12-24 weeks after the disease onset may contribute to the increase in CVD risk in the post-COVID-19 period.

Causal Association Between Type 2 Diabetes Mellitus and Alzheimer's Disease: A Two-Sample Mendelian Randomization Study

Background

There is now increasing evidence that type 2 diabetes mellitus (T2DM) is associated with Alzheimer's disease (AD). However, it is unclear whether the two are causally related.

Objective

To reveal the causal association between T2DM and AD, we performed a bidirectional Mendelian randomization (MR) analysis.

Methods

Genetic instrumental variables were systematically screened, and inverse-variance weighting, MR-Egger regression, weighted median, simple mode, and weighted mode were applied to assess the pathogenic associations between the two diseases, and sensitivity analyses were used to further validate the robustness of the results.

Results

The results of forward MR analysis with T2DM as the exposure were [OR = 0.998, 95% CI (0.975∼1.021), p = 0.857], and the results of reverse MR analysis with AD as the exposure were [OR = 0.966, 95% CI (0.934∼0.999), p = 0.043]. The results showed no significant association between T2DM and AD at the gene level (p < 0.025). Sensitivity analyses were consistent with the results of the main analysis, confirming the robustness of the study.

Conclusions

T2DM and AD may not be genetically causally associated.

Molecular cross-talk between long COVID-19 and Alzheimer's disease

The long COVID (coronavirus disease), a multisystemic condition following severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, is one of the widespread problems. Some of its symptoms affect the nervous system and resemble symptoms of Alzheimer's disease (AD)-a neurodegenerative condition caused by the accumulation of amyloid beta and hyperphosphorylation of tau proteins. Multiple studies have found dependence between these two conditions. Patients with Alzheimer's disease have a greater risk of SARS-CoV-2 infection due to increased levels of angiotensin-converting enzyme 2 (ACE2), and the infection itself promotes amyloid beta generation which enhances the risk of AD. Also, the molecular pathways are alike-misregulations in folate-mediated one-carbon metabolism, a deficit of Cq10, and disease-associated microglia. Medical imaging in both of these diseases shows a decrease in the volume of gray matter, global brain size reduction, and hypometabolism in the parahippocampal gyrus, thalamus, and cingulate cortex. In some studies, a similar approach to applied medication can be seen, including the use of amino adamantanes and phenolic compounds of rosemary. The significance of these connections and their possible application in medical practice still needs further study but there is a possibility that they will help to better understand long COVID.

Climate Stressors and Physiological Dysregulations: Mechanistic Connections to Pathologies

This review delves into the complex relationship between environmental factors, their mechanistic cellular and molecular effects, and their significant impact on human health. Climate change is fueled by industrialization and the emission of greenhouse gases and leads to a range of effects, such as the redistribution of disease vectors, higher risks of disease transmission, and shifts in disease patterns. Rising temperatures pose risks to both food supplies and respiratory health. The hypothesis addressed is that environmental stressors including a spectrum of chemical and pathogen exposures as well as physical and psychological influences collectively impact genetics, metabolism, and cellular functions affecting physical and mental health. The objective is to report the mechanistic associations linking environment and health. As environmental stressors intensify, a surge in health conditions, spanning from allergies to neurodegenerative diseases, becomes evident; however, linkage to genetic-altered proteomics is more hidden. Investigations positing that environmental stressors cause mitochondrial dysfunction, metabolic syndrome, and oxidative stress, which affect missense variants and neuro- and immuno-disorders, are reported. These disruptions to homeostasis with dyslipidemia and misfolded and aggregated proteins increase susceptibility to cancers, infections, and autoimmune diseases. Proposed interventions, such as vitamin B supplements and antioxidants, target oxidative stress and may aid mitochondrial respiration and immune balance. The mechanistic interconnections of environmental stressors and disruptions in health need to be unraveled to develop strategies to protect public health.

From Cell to Symptoms: The Role of SARS-CoV-2 Cytopathic Effects in the Pathogenesis of COVID-19 and Long COVID

Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) infection triggers various events from molecular to tissue level, which in turn is given by the intrinsic characteristics of each patient. Given the molecular diversity characteristic of each cellular phenotype, the possible cytopathic, tissue and clinical effects are difficult to predict, which determines the heterogeneity of COVID-19 symptoms. The purpose of this article is to provide a comprehensive review of the cytopathic effects of SARS-CoV-2 on various cell types, focusing on the development of COVID-19, which in turn may lead, in some patients, to a persistence of symptoms after recovery from the disease, a condition known as long COVID. We describe the molecular mechanisms underlying virus-host interactions, including alterations in protein expression, intracellular signaling pathways, and immune responses. In particular, the article highlights the potential impact of these cytopathies on cellular function and clinical outcomes, such as immune dysregulation, neuropsychiatric disorders, and organ damage. The article concludes by discussing future directions for research and implications for the management and treatment of COVID-19 and long COVID.

Overview and New Insights into the Metabolic Syndrome: Risk Factors and Emerging Variables in the Development of Type 2 Diabetes and Cerebrocardiovascular Disease

Metabolic syndrome (MetS) is considered a metabolic disorder that has been steadily increasing globally and seems to parallel the increasing prevalence of obesity. It consists of a cluster of risk factors which traditionally includes obesity and hyperlipidemia, hyperinsulinemia, hypertension, and hyperglycemia. These four core risk factors are associated with insulin resistance (IR) and, importantly, the MetS is known to increase the risk for developing cerebrocardiovascular disease and type 2 diabetes mellitus. The MetS had its early origins in IR and syndrome X. It has undergone numerous name changes, with additional risk factors and variables being added over the years; however, it has remained as the MetS worldwide for the past three decades. This overview continues to add novel insights to the MetS and suggests that leptin resistance with hyperleptinemia, aberrant mitochondrial stress and reactive oxygen species (ROS), impaired folate-mediated one-carbon metabolism with hyperhomocysteinemia, vascular stiffening, microalbuminuria, and visceral adipose tissues extracellular vesicle exosomes be added to the list of associated variables. Notably, the role of a dysfunctional and activated endothelium and deficient nitric oxide bioavailability along with a dysfunctional and attenuated endothelial glycocalyx, vascular inflammation, systemic metainflammation, and the important role of ROS and reactive species interactome are discussed. With new insights and knowledge regarding the MetS comes the possibility of new findings through further research.

Profiling of Homocysteine Metabolic Pathway Related Metabolites in Plasma of Diabetic Mellitus Based on LC-QTOF-MS

Background: Homocysteine (Hcy) has been found to be closely related to the occurrence of diabetes mellitus (DM) and is considered as one of the risk factors of DM. However, Hcy alone is not enough as a factor to predict DM, and our study analyzed and determined the relationship between the main metabolites involved in the Hcy metabolic pathway and DM. Methods: A total of 48 clinical samples were collected, including 18 health control samples and 30 DM samples. All standards and samples were detected by LC-QTOF-MS. Multivariate statistical analysis and k-means cluster analysis were performed to screen and confirm the metabolites significantly correlated with DM. Results: A total of 13 metabolites of the Hcy metabolic pathway were detected in the samples. The content of Hcy, cysteine, taurine, pyridoxamine, methionine, and choline were significantly increased in the DM group (p < 0.05). Hcy, choline, cystathionine, methionine, and taurine contributed significantly to the probabilistic principal component analysis (PPCA) model. The odds ratios (OR) of Hcy, cysteine, taurine, methionine, and choline were all greater than one. K-means cluster analysis showed that the Hcy, taurine, methionine, and choline were significantly correlated with the distribution of glucose values (divided into four levels: 10.5−11.7 mmol/L, 7.7−9.7 mmol/L, 6.0−6.9 mmol/L, and 5.0−5.9 mmol/L, respectively). Conclusion: Hcy, taurine, methionine, and choline can be used as risk factors for diabetes diagnosis and are expected to be used for the assessment of diabetes severity.

A Study of the Metabolic Pathways Affected by Gestational Diabetes Mellitus: Comparison with Type 2 Diabetes

BACKGROUND

Gestational diabetes mellitus (GDM) remains incompletely understood and increases the risk of developing Diabetes mellitus type 2 (DM2). Metabolomics provides insights etiology and pathogenesis of disease and discovery biomarkers for accurate detection. Nuclear magnetic resonance (NMR) spectroscopy is a key platform defining metabolic signatures in intact serum/plasma. In the present study, we used NMR-based analysis of macromolecules free-serum to accurately characterize the altered metabolic pathways of GDM and assessing their similarities to DM2. Our findings could contribute to the understanding of the pathophysiology of GDM and help in the identification of metabolomic markers of the disease.

METHODS

Sixty-two women with GDM matched with seventy-seven women without GDM (control group). ¹H NMR serum spectra were acquired on an 11.7 T Bruker Avance DRX NMR spectrometer.

RESULTS

We identified 55 metabolites in both groups, 25 of which were significantly altered in the GDM group. GDM group showed elevated levels of ketone bodies, 2-hydroxybutyrate and of some metabolic intermediates of branched-chain amino acids (BCAAs) and significantly lower levels of metabolites of one-carbon metabolism, energy production, purine metabolism, certain amino acids, 3-methyl-2-oxovalerate, ornithine, 2-aminobutyrate, taurine and trimethylamine N-oxide.

CONCLUSION

Metabolic pathways affected in GDM were beta-oxidation, ketone bodies metabolism, one-carbon metabolism, arginine and ornithine metabolism likewise in DM2, whereas BCAAs catabolism and aromatic amino acids metabolism were affected, but otherwise than in DM2.

Palm Oil Derived Tocotrienol-Rich Fraction Attenuates Vascular Dementia in Type 2 Diabetic Rats

Vascular dementia (VaD) is a serious global health issue and type 2 diabetes mellitus (T2DM) patients are at higher risk. Palm oil tocotrienol-rich fraction (TRF) exhibits neuroprotective properties; however, its effect on VaD is not reported. Hence, we evaluated TRF effectiveness in T2DM-induced VaD rats. Rats were given a single dose of streptozotocin (STZ) and nicotinamide (NA) to develop T2DM. Seven days later, diabetic rats were given TRF doses of 30, 60, and 120 mg/kg orally for 21 days. The Morris water maze (MWM) test was performed for memory assessment. Biochemical parameters such as blood glucose, plasma homocysteine (HCY) level, acetylcholinesterase (AChE) activity, reduced glutathione (GSH), superoxide dismutase (SOD) level, and histopathological changes in brain hippocampus and immunohistochemistry for platelet-derived growth factor-C (PDGF-C) expression were evaluated. VaD rats had significantly reduced memory, higher plasma HCY, increased AChE activity, and decreased GSH and SOD levels. However, treatment with TRF significantly attenuated the biochemical parameters and prevented memory loss. Moreover, histopathological changes were attenuated and there was increased PDGF-C expression in the hippocampus of VaD rats treated with TRF, indicating neuroprotective action. In conclusion, this research paves the way for future studies and benefits in understanding the potential effects of TRF in VaD rats.

Associations of folate intake with all-cause and cause-specific mortality among individuals with diabetes

Background and aims

The evidence regarding folate intake and mortality risk among patients with type 2 diabetes (T2D) remains unclear. This study aimed to investigate the association of folate intake with the risk of mortality among individuals with T2D.

Methods

A total of 9,196 participants with T2D from the Third National Health and Nutrition Examination Survey (NHANES III) and NHANES 1999–2014 were included. The data of survival were obtained by the cohort database linked with the national death index up to 31 December 2015. The Cox proportional hazard model was used to evaluate the relationship between dietary folate with all-cause and cause-specific mortality.

Results

Among patients with T2D, dietary folate intake was negatively correlated with all-cause mortality, cardiovascular mortality, and cancer mortality in men, and for women with all-cause mortality and cardiovascular mortality. The multivariate adjustment hazard ratio (HR) (95% CIs) for men of highest vs. lowest quartile was 0.77 (0.66–0.90), 0.61 (0.45–0.83), and 0.70 (0.49–0.99) for all-cause, cardiovascular, and cancer mortality, respectively. Among women, the multivariate adjustment HR (95% CIs) of highest vs. lowest quartile was 0.77 (0.64–0.92), 0.52 (0.33–0.83), and 0.78 (0.50–1.22) for all-cause, cardiovascular, and cancer mortality, respectively.

Conclusion

Higher dietary intake of folate was significantly associated with lower all-cause and cardiovascular mortality. This cohort study suggested that increasing the dietary folate intake may reduce mortality risk among U.S. adults with T2D.

Suboptimal Consumption of Relevant Immune System Micronutrients Is Associated with a Worse Impact of COVID-19 in Spanish Populations

Coronavirus disease 2019 (COVID-19) has caused a global health crisis and the factors behind its differential impact on COVID-19 among populations are still being known. Geographical differences in nutrient profile could be a relevant factor, especially considering that scientific evidence supports that 10 micronutrients are essential for proper immune system function. This study aims to evaluate these micronutrient intakes in the territories of Spain and to analyze their relationship with epidemiological indicators of COVID-19 from the first two waves of COVID-19, when neither specific vaccines nor drugs had yet come into play. Results showed that vitamin D, A, B₉, and zinc intakes were particularly insufficient in Spain. The joint intake of these four micronutrients was lower in regions with the highest COVID-19 incidence and mortality, and of particular importance, was the insufficient intake of vitamin D. A pattern of food consumption associated with lower COVID-19 impact was observed. In conclusion, the results show the relevance of the optimal consumption of foods rich in essential nutrients for the immune system. Therefore, this assessment could serve to launch specific dietary recommendations to strengthen the immune system in Spanish territories to better face potential new COVID-19 variants and/or further infectious diseases.

The Mighty Mitochondria Are Unifying Organelles and Metabolic Hubs in Multiple Organs of Obesity, Insulin Resistance, Metabolic Syndrome, and Type 2 Diabetes: An Observational Ultrastructure Study

Mitochondria (Mt) are essential cellular organelles for the production of energy and thermogenesis. Mt also serve a host of functions in addition to energy production, which include cell signaling, metabolism, cell death, and aging. Due to the central role of Mt in metabolism as metabolic hubs, there has been renewed interest in how Mt impact metabolic pathways and multiple pathologies. This review shares multiple observational ultrastructural findings in multiple cells and organs to depict aberrant mitochondrial (aMt) remodeling in pre-clinical rodent models. Further, it is intended to show how remodeling of Mt are associated with obesity, insulin resistance, metabolic syndrome (MetS), and type 2 diabetes mellitus (T2DM). Specifically, Mt remodeling in hypertensive and insulin-resistant lean models (Ren2 rat models), lean mice with streptozotocin-induced diabetes, obesity models including diet-induced obesity, genetic leptin-deficient ob/ob, and leptin receptor-deficient db/db diabetic mice are examined. Indeed, aMt dysfunction and damage have been implicated in multiple pathogenic diseases. Manipulation of Mt such as the induction of Mt biogenesis coupled with improvement of mitophagy machinery may be helpful to remove leaky damaged aMt in order to prevent the complications associated with the generation of superoxide-derived reactive oxygen species and the subsequent reactive species interactome. A better understanding of Mt remodeling may help to unlock many of the mysteries in obesity, insulin resistance, MetS, T2DM, and the associated complications of diabetic end-organ disease.

COVID-19 and One-Carbon Metabolism

Dysregulation of one-carbon metabolism affects a wide range of biological processes and is associated with a number of diseases, including cardiovascular disease, dementia, neural tube defects, and cancer. Accumulating evidence suggests that one-carbon metabolism plays an important role in COVID-19. The symptoms of long COVID-19 are similar to those presented by subjects suffering from vitamin B₁₂ deficiency (pernicious anemia). The metabolism of a cell infected by the SARS-CoV-2 virus is reshaped to fulfill the need for massive viral RNA synthesis, which requires de novo purine biosynthesis involving folate and one-carbon metabolism. Many aspects of host sulfur amino acid metabolism, particularly glutathione metabolism underlying antioxidant defenses, are also taken over by the SARS-CoV-2 virus. The purpose of this review is to summarize recent findings related to one-carbon metabolism and sulfur metabolites in COVID-19 and discuss how they inform strategies to combat the disease.