Interaction of Severe Acute Respiratory Syndrome Coronavirus 2 and Diabetes

Association between Methylenetetrahydrofolate Reductase (MTHFR) and 5-Methyltetrahydrofolate-Homocysteine Methyltransferase Reductase (MTRR) Polymorphisms in Iraqi Patients with COVID-19

Background

The methylenetetrahydrofolate reductase (MTHFR) gene is an essential gene in the metabolism of folate-homocysteine. Recently, the level of homocysteine was found to be a significant marker in the follow-up of COVID-19 infection. Thus, this study aimed to detect the effect of genetic polymorphisms for single nucleotide polymorphisms (SNPs) (c.66A>G, c.1298A>C, and c.677CT) on COVID-19 infection.

Methods

Blood samples were collected from 270 patients with COVID-19 in the medical center of Al-Shifa (Baghdad, Iraq) from November 2020 to March 2021. Tetra-primer amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) technique was used for the detection of genotypes of SNPs. The odds ratio (OR) was used to detect the relationship between SNPs and COVID-19 infections. Haplotype analysis was performed by SHEsis software.

Results

There was a significant difference between mild/moderate cases and severe/critical cases for ages (35-45), (46-55), and (56-65) years (P<0.0001, P=0.01, and P=0.006, respectively). The results showed significant differences in the T allele for SNP c.677>C (P<0.0001 and OR=4.58). The C allele for SNP c.1298A>C indicated significant differences (P<0.001 and OR=3.15). Besides, the G allele for SNP c.677C>T showed significant differences (P<0.001 and OR=6.64). Consequently, these SNPs showed a predisposition to the development of COVID-19 infection. With regard to the C-A-A, T-A-A and T-C-G haplotypes indicated significant differences between the control and patient groups. The C-A-A was related to a decreased risk and indicated a protective effect against COVID-19 infection development (P<0.0001 and OR=0.218). The increased risk was associated with T-A-A and T-C-G haplotypes and indicated the risk impact on COVID-19 infection development (P<0.0001, P=0.004, and OR=15.5, OR=6.772, respectively). Furthermore, the linkage disequilibrium (LD) for SNPs was studied, and the complete D' value was 99.

Conclusion

The genetic polymorphisms of SNPs (c.66A>G, c.1298A>C, and c.677C>T) in the Iraqi population were associated with COVID-19 infection.

The relationship between SARS-CoV-2 infection and type 1 diabetes mellitus

Environmental factors, in particular viral infections, are thought to have an important role in the pathogenesis of type 1 diabetes mellitus (T1DM). The COVID-19 pandemic reinforced this hypothesis as many observational studies and meta-analyses reported a notable increase in the incidence of T1DM following infection with SARS-CoV-2 as well as an association between SARS-CoV-2 infection and the risk of new-onset T1DM. Experimental evidence suggests that human β-cells express SARS-CoV-2 receptors and that SARS-CoV-2 can infect and replicate in β-cells, resulting in structural or functional alterations of these cells. These alterations include reduced numbers of insulin-secreting granules, impaired pro-insulin (or insulin) secretion, and β-cell transdifferentiation or dedifferentiation. The inflammatory environment induced by local or systemic SARS-CoV-2 infection might result in a set of signals (such as pro-inflammatory cytokines) that lead to β-cell alteration or apoptosis or to a bystander activation of T cells and disruption of peripheral tolerance that triggers autoimmunity. Other mechanisms, such as viral persistence, molecular mimicry and activation of endogenous human retroviruses, are also likely to be involved in the pathogenesis of T1DM following SARS-CoV-2 infection. This Review addresses the issue of the involvement of SARS-CoV-2 infection in the development of T1DM using evidence from epidemiological, clinical and experimental studies.

Inflammageing mediated by cytotoxic lymphocytes is associated with diabetes duration

AIMS

Inflammageing, the age-related systemic increase of proinflammatory factors, has been linked to the development of cardiovascular disease, chronic kidney disease and cancer in the elderly. Chronic inflammation is believed to be a causative factor in the development of diabetic complications. However, exactly how type 2 diabetes impacts the inflammatory state of the immune system is incompletely characterised.

METHODS

Blood collection and anthropometric measurements were performed in patients with type 2 diabetes (n = 49) and control subjects (n = 30). The phenotype, proliferation capacity and cytokine production by cytotoxic lymphocytes were analysed using multiparametric flow cytometry.

RESULTS

Type 2 diabetes did not impact the phenotype or proliferation of the investigated cells. However, we observed a significantly increased production of tumour necrosis factor-α by CD8+ T cells and Granzyme B by natural killer cells and γδ T cells compared to controls. Hyperresponsiveness of cytotoxic blood lymphocytes did not correlate with glycaemia or body mass index, but instead was associated with older age and longer diabetes duration.

CONCLUSIONS

Type 2 diabetes is associated with an increased pro-inflammatory potential of cytotoxic blood lymphocytes correlating with age and diabetes duration. Further research is necessary to explore potential benefits of diabetes medications in reverting this effect.

Post-COVID syndrome, inflammation, and diabetes

The raging COVID-19 pandemic is in its third year of global impact. The SARS CoV 2 virus has a high rate of spread, protean manifestations, and a high morbidity and mortality in individuals with predisposing risk factors. The pathophysiologic mechanisms involve a heightened systemic inflammatory state, cardiometabolic derangements, and varying degrees of glucose intolerance. The latter can be evident as significant hyperglycemia leading to new-onset diabetes or worsening of preexisting disease. Unfortunately, the clinical course beyond the acute phase of the illness may persist in the form of a variety of symptoms that together form the so-called "Long COVID" or "Post-COVID Syndrome". It is thought that a chronic, low-grade inflammatory and immunologic state persists during this phase, which may last for weeks or months. Although numerous insights have been gained into COVID-related hyperglycemia and diabetes, its prediction, course, and management remain to be fully elucidated.

Non-Insulin Novel Antidiabetic Drugs Mechanisms in the Pathogenesis of COVID-19

The present study aimed to analyse the published data and to realize an update about the use and pathogenesis of the novel antidiabetic drugs, respectively, dipeptidyl peptidase-4 inhibitors (DPP-4i), glucagon-like peptide-1 receptor agonists (GLP-1 Ra), and sodium-glucose co-transporter-2 inhibitors (SGLT-2i), in patients with type 2 diabetes mellitus (T2DM) and coronavirus disease (COVID-19). Literature research in the PubMed and Web of Science database was performed in order to identify relevant published clinical trials and meta-analyses that include information about the treatment with novel antidiabetic agents in patients with T2DM and COVID-19. A total of seven articles were included, and their primary and secondary outcomes were reported and analysed. DPP-4i has mixed results on mortality in T2DM patients with COVID-19 but with an overall slightly favourable or neutral effect, whereas GLP-1 Ra seems to have a rather beneficial impact, while SGLT-2i may be useful in acute illness. Even if there are limited data, they seem to have favourable efficacy and safety profiles. The available evidence is heterogenous and insufficient to evaluate if the benefits of non-insulin novel antidiabetic drugs in COVID-19 treatment are due to the improvement of glycaemic control or to their intrinsic anti-inflammatory effects but highlights their beneficial effects in the pathogenesis and evolution of the disease.

Is There Any Correlation between Baseline Serum Cortisol Levels and Disease Severity in PCR-Positive COVID-19 Patients with and without Diabetes Mellitus?

Background: COVID-19 has caused a pandemic and is associated with significant mortality. The pathophysiology of COVID-19, affecting many organs and systems, is still being investigated. The hypothalamus, pituitary gland, and possibly adrenal glands are the targets of SARS-CoV-2 because of its angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) receptors expression. Hypocortisolemia can be seen in the postinfection period. COVID-19 infection tends to be severe in diabetic patients due to immune dysfunction. In this study, our aim was to investigate the relationship between basal cortisol levels and the course of COVID-19 infection in diabetic and non-diabetic patients. Methods: Our retrospective study included 311 PCR-positive COVID-19 patients over the age of 18 who were hospitalized in Ankara City Hospital Infectious Diseases Department or Intensive Care Unit (ICU) between 15 March 2020 and 15 May 2020. Serum basal cortisol, fasting plasma glucose (FPG), HbA1c values, and diabetes history were recorded within the first 24 h of hospitalization. The presence of pulmonary involvement was noted from the patients’ imaging records. Pregnant and breastfeeding women, patients with chronic liver disease or chronic kidney disease, and patients who were already using steroids or had started COVID-19 infection treatment within the 72 h before blood collection were excluded from the study. Results: Of the 311 patients, 100 had Type 2 Diabetes Mellitus (T2D), while 211 did not. The age, serum basal cortisol, and glucose levels of the patients with T2D (64.51 ± 12.29, 19.5 ± 13.12, and 143.5 (77−345)) were higher than those of the patients without T2D (46.67 ± 16.38, 15.26 ± 8.75, and 96 (65−202)), and the differences were statistically significant (p = 0.004, p = 0.004, and p < 0.001, respectively). The basal cortisol values of the ICU patients (27.89 (13.91−75)) were significantly higher than those of the ward patients (13.68 (1.48−51.93)) and patients who were transferred to the ICU from the ward due to worsening conditions (19.28 (7.74−55.21)) (p < 0.001 and p = 0.007, respectively). The factors affecting ICU admission were determined to be age, T2D history, basal cortisol, and elevation in FPG using univariate logistic regression analysis. In the multiple logistic regression analysis, age, basal cortisol level, and infiltrative involvement in thorax CT were determined to be the risk factors affecting intensive care admission. Conclusion: High basal cortisol levels in patients with T2D may predict the severity of COVID-19 infection or mortality. Although high basal cortisol levels are among the risk factors affecting ICU admission, patients with COVID-19 should also be evaluated in terms of clinical and laboratory findings and relative adrenal insufficiency.

Obesity and COVID-19: Mechanistic Insights From Adipose Tissue

Obesity is associated with an increase in morbidity and mortality from coronavirus disease 2019 (COVID-19). The risk is related to the cytokine storm, a major contributor to multiorgan failure and a pathological character of COVID-19 patients with obesity. While the exact cause of the cytokine storm remains elusive, disorders in energy metabolism has provided insights into the mechanism. Emerging data suggest that adipose tissue in obesity contributes to the disorders in several ways. First, adipose tissue restricts the pulmonary function by generation of mechanical pressures to promote systemic hypoxia. Second, adipose tissue supplies a base for severe acute respiratory syndrome coronavirus 2 entry by overexpression of viral receptors [angiotensin-converting enzyme 2 and dipeptidyl peptidase 4]. Third, impaired antiviral responses of adipocytes and immune cells result in dysfunction of immunologic surveillance as well as the viral clearance systems. Fourth, chronic inflammation in obesity contributes to the cytokine storm by secreting more proinflammatory cytokines. Fifth, abnormal levels of adipokines increase the risk of a hyperimmune response to the virus in the lungs and other organs to enhance the cytokine storm. Mitochondrial dysfunction in adipocytes, immune cells, and other cell types (endothelial cells and platelets, etc) is a common cellular mechanism for the development of cytokine storm, which leads to the progression of mild COVID-19 to severe cases with multiorgan failure and high mortality. Correction of energy surplus through various approaches is recommended in the prevention and treatment of COVID-19 in the obese patients.

SIT1 transporter as a potential novel target in treatment of COVID-19

Studies published earlier this year demonstrated the association of the solute carrier SLC6A20 gene with the risk and severity of COVID-19. The SLC6A20 protein product (Sodium-dependent Imino Transporter 1 (SIT1)) is involved in the transport of amino acids, including glycine. Here we summarized the results of recent studies demonstrating the interaction of SIT1 with the ACE2 receptor for SARS-CoV-2 as well as an observed association of SLC6A20 with the risk and traits of Type 2 diabetes (T2D). Recently, it was also proposed that SLC6A20 represents the novel regulator of glycine levels and that glycine has beneficial effects against the proinflammatory cytokine secretion induced by SARS-CoV-2 infection. Ivermectin, as a partial agonist of glycine-gated chloride channels, was also recently suggested to interfere with the COVID-19 cytokine storm by inducing the activation of glycine receptors. Furthermore, plasma glycine levels are found to be decreased in diabetic patients. Thus, further clinical trials are warranted to confirm the potential favorable effects of targeting the SIT1 transporter and glycine levels in the treatment of COVID-19, particularly for the severe case of disease associated with hyperglycemia, inflammation, and T2D. These findings suggest that SIT1 may potentially represent one of the missing pieces in the complex puzzle observed between these two pandemic diseases and the potential novel target for their efficient treatment.

A Randomized Clinical Trial of Linagliptin vs. Standard of Care in Patients Hospitalized With Diabetes and COVID-19

OBJECTIVE

To assess the effect of linagliptin vs. standard therapy in improving clinical outcomes in patients hospitalized with diabetes and coronavirus disease 2019 (COVID-19).

MATERIALS AND METHODS

We did an open-label, prospective, multicenter, randomized clinical trial in 3 Israeli hospitals between October 1, 2020, and April 4, 2021. Eligible patients were adults with type 2 diabetes mellitus and a diagnosis of COVID-19. A total of 64 patients, 32 in each group, were randomized to receive linagliptin 5 mg PO daily throughout the hospitalization or standard of care therapy. The primary outcome was time to clinical improvement within 28 days after randomization, defined as a 2-point reduction on an ordinal scale ranging from 0 (discharged without disease) to 8 (death).

RESULTS

The mean age was 67 ± 14 years, and most patients were male (59.4%). Median time to clinical improvement was 7 days (interquartile range (IQR) 3.5-15) in the linagliptin group compared with 8 days (IQR 3.5-28) in the standard of care group (hazard ratio, 1.22; 95% CI, 0.70-2.15; p = 0.49). In-hospital mortality was 5 (15.6%) and 8 (25.0%) in the linagliptin and standard of care groups, respectively (odds ratio, 0.56; 95% CI, 0.16-1.93). The trial was prematurely terminated due to the control of the COVID-19 outbreak in Israel.

CONCLUSIONS

In this randomized clinical trial of hospitalized adult patients with diabetes and COVID-19 who received linagliptin, there was no difference in the time to clinical improvement compared with the standard of care.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT04371978.