A geroscience perspective on immune resilience and infectious diseases: a potential case for metformin

Depression, Inflammation, and the Moderating Role of Metformin: Results From the Midlife in the United States Study and Sacramento Area Latino Study on Aging

OBJECTIVE

Depression can promote inflammation and accelerate aging. Metformin, a widely prescribed antidiabetic, has shown promising preclinical evidence of aging-related health benefits, including decreased inflammation. The current study examined whether metformin usage buffers the association between depressive symptoms and inflammatory markers in two large samples of middle-aged and older, primarily White adults, and older Latino adults.

METHODS

Data from the Midlife in the United States Study ( N = 1255) and the Sacramento Area Latino Study on Aging ( N = 1786) included information on medication use, depressive symptoms, and inflammatory markers, namely, interleukin 6 (IL-6), tumor necrosis factor α, and C-reactive protein (CRP). These data were merged into a harmonized sample, and the sample group variable was included in a three-way interaction for analysis.

RESULTS

Specifically, in the Midlife in the United States Study sample, metformin buffered the association between depressive symptoms and CRP ( b = -0.029, standard error [SE] = 0.013, p = .007) and IL-6 ( b = 0.21, SE = 0.010, p = .046), whereas no significant association was found with tumor necrosis factor α. Metformin nonusers displayed higher depressive symptoms associated with elevated CRP ( b = 0.01, SE = 0.003, p < .001) and IL-6 ( b = 0.011, SE = 0.003, p < .001), whereas this association was not present among metformin users ( p values > .068). Conversely, in the Sacramento Area Latino Study on Aging sample, metformin use did not show a significant protective link.

CONCLUSIONS

Results from mostly White, highly educated adults supported a mitigating role of metformin in ties between depression, a well-known behavioral risk factor, and inflammation, a key source of biological aging. However, the benefits did not extend to a large sample of older Mexican Americans. The findings reveal a hidden potential benefit of this therapeutic agent and raise important questions around its health equity.

TRIAL REGISTRATION

The study was preregistered on OSF ( https://osf.io/c92vw/ ).

Geroscience and pathology: a new frontier in understanding age-related diseases

Geroscience, a burgeoning discipline at the intersection of aging and disease, aims to unravel the intricate relationship between the aging process and pathogenesis of age-related diseases. This paper explores the pivotal role played by geroscience in reshaping our understanding of pathology, with a particular focus on age-related diseases. These diseases, spanning cardiovascular and cerebrovascular disorders, malignancies, and neurodegenerative conditions, significantly contribute to the morbidity and mortality of older individuals. We delve into the fundamental cellular and molecular mechanisms underpinning aging, including mitochondrial dysfunction and cellular senescence, and elucidate their profound implications for the pathogenesis of various age-related diseases. Emphasis is placed on the importance of assessing key biomarkers of aging and biological age within the realm of pathology. We also scrutinize the interplay between cellular senescence and cancer biology as a central area of focus, underscoring its paramount significance in contemporary pathological research. Moreover, we shed light on the integration of anti-aging interventions that target fundamental aging processes, such as senolytics, mitochondria-targeted treatments, and interventions that influence epigenetic regulation within the domain of pathology research. In conclusion, the integration of geroscience concepts into pathological research heralds a transformative paradigm shift in our understanding of disease pathogenesis and promises breakthroughs in disease prevention and treatment.

mTORC1 inhibition may improve T lymphocytes affected by aging

BACKGROUND

Due to the increase of the elderly's population and related social and economic problems, it is very important to provide strategies on health. In this regard, induction of T lymphocytes responses, the most important cells of the immune system, may be a good approach. Among different agents considered as antiaging factors, mTORC1 pathway inhibitors are significant. So, the purpose of this study was to evaluate the effect of two mTORC1 inhibitors, Everolimus and Metformin, on age-related features of activated T cells.

MATERIALS AND METHODS

Optimum doses of drugs was determined with evaluating the effect of treatments on IL-2 gene expression. T cells isolated from old and young mice were treated with drugs and PHA. IL-2 production was evaluated by ELISA. Also, the expression of CD28, PD-1, and KLRG-1, proliferation, and intracellular oxidative stress were assessed by flow cytometry-based assays, phenotyping, CFSE, and DCF-DA assay respectively.

RESULTS

Both drugs increased IL-2 production in the T cells of old mice. Also, using drugs especially Metformin could improve age-related phenotypical markers and increase the proliferation of T cells of old mice significantly. In addition, Metformin and Everolimus reduced intracellular oxidative stress in aged cells. However, the effect of both drugs on the T cells of young mice wasn't significant or was in opposite to the results of old mice T cells.

DISCUSSION

In line with studies noting mTOR inhibitors as antiaging drugs, Metformin and Everolimus may improve T cells affected from aging in vitro, and a decrease in intracellular oxidative stress may be one of their mechanism of function.

Disuse-induced muscle fibrosis, cellular senescence, and senescence-associated secretory phenotype in older adults are alleviated during re-ambulation with metformin pre-treatment

Muscle inflammation and fibrosis underlie disuse-related complications and may contribute to impaired muscle recovery in aging. Cellular senescence is an emerging link between inflammation, extracellular matrix (ECM) remodeling and poor muscle recovery after disuse. In rodents, metformin has been shown to prevent cellular senescence/senescent associated secretory phenotype (SASP), inflammation, and fibrosis making it a potentially practical therapeutic solution. Thus, the purpose of this study was to determine in older adults if metformin monotherapy during bed rest could reduce muscle fibrosis and cellular senescence/SASP during the re-ambulation period. A two-arm controlled trial was utilized in healthy male and female older adults (n = 20; BMI: <30, age: 60 years+) randomized into either placebo or metformin treatment during a two-week run-in and 5 days of bedrest followed by metformin withdrawal during 7 days of recovery. We found that metformin-treated individuals had less type-I myofiber atrophy during disuse, reduced pro-inflammatory transcriptional profiles, and lower muscle collagen deposition during recovery. Collagen content and myofiber size corresponded to reduced whole muscle cellular senescence and SASP markers. Moreover, metformin treatment reduced primary muscle resident fibro-adipogenic progenitors (FAPs) senescent markers and promoted a shift in fibroblast fate to be less myofibroblast-like. Together, these results suggest that metformin pre-treatment improved ECM remodeling after disuse in older adults by possibly altering cellular senescence and SASP in skeletal muscle and in FAPs.

Old drug, new tricks: the utility of metformin in infection and vaccination responses to influenza and SARS-CoV-2 in older adults

In the face of global pathogens such as influenza (flu) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), strategies beyond standard vaccines and virus-specific treatments are critically needed for older populations who are more susceptible to severe disease and death from these infections due to age-related immune dysregulation. Thus, complimentary therapeutics are needed to address the increased risk of complications and death in older adults. Metformin, an FDA approved diabetes drug, is an attractive therapeutic candidate to improve immune defenses and resilience in older adults facing viral challenge. Metformin is already a candidate anti-aging drug, but its benefits have potential to span beyond this and improve specific immune responses. Metformin can target multiple aging hallmarks as well as directly impact innate and adaptive immune cell subsets. Both retrospective and prospective studies have demonstrated metformin's efficacy in improving outcomes after SARS-CoV-2 or flu infections. Moreover, evidence from clinical trials has also suggested that metformin treatment can improve vaccination responses. In totality, these findings suggest that metformin can improve age-related declines in immunological resilience. Strategies to improve outcomes after infection or improve vaccine-induced protection are invaluable for older adults. Moreover, the ability to repurpose an already FDA approved drug has significant advantages in terms of necessary time and resources. Thus, metformin has great potential as a therapeutic to improve age-related immune dysregulation during flu and SARS-CoV-2 infections and should be further explored to confirm its ability to improve overall immunological resilience in older adults.

Unveiling the potential pleiotropic effects of metformin in treating COVID-19: a comprehensive review

This review article explores the potential of metformin, a medication commonly used for type 2 diabetes, as an antiviral and anti-inflammatory agent in the context of coronavirus disease 2019 (COVID-19). Metformin has demonstrated inhibitory effects on the growth of SARS-CoV-2 in cell culture models and has shown promising results in reducing viral load and achieving undetectable viral levels in clinical trials. Additionally, metformin exhibits anti-inflammatory properties by reducing the production of pro-inflammatory cytokines and modulating immune cell function, which may help prevent cytokine storms associated with severe COVID-19. The drug's ability to regulate the balance between pro-inflammatory Th17 cells and anti-inflammatory Treg cells suggests its potential in mitigating inflammation and restoring T cell functionality. Furthermore, metformin's modulation of the gut microbiota, particularly changes in bacterial taxa and the production of short-chain fatty acids, may contribute to its therapeutic effects. The interplay between metformin, bile acids, the gut microbiome, glucagon-like peptide-1 secretion, and glycemic control has implications for the management of diabetes and potential interventions in COVID-19. By refreshing the current evidence, this review highlights the potential of metformin as a therapeutic option in the management of COVID-19, while also exploring its effects on the gut microbiome and immunometabolism.

The central role of DNA damage in immunosenescence

Ageing is the biggest risk factor for the development of multiple chronic diseases as well as increased infection susceptibility and severity of diseases such as influenza and COVID-19. This increased disease risk is linked to changes in immune function during ageing termed immunosenescence. Age-related loss of immune function, particularly in adaptive responses against pathogens and immunosurveillance against cancer, is accompanied by a paradoxical gain of function of some aspects of immunity such as elevated inflammation and increased incidence of autoimmunity. Of the many factors that contribute to immunosenescence, DNA damage is emerging as a key candidate. In this review, we discuss the evidence supporting the hypothesis that DNA damage may be a central driver of immunosenescence through senescence of both immune cells and cells of non-haematopoietic lineages. We explore why DNA damage accumulates during ageing in a major cell type, T cells, and how this may drive age-related immune dysfunction. We further propose that existing immunosenescence interventions may act, at least in part, by mitigating DNA damage and restoring DNA repair processes (which we term "genoprotection"). As such, we propose additional treatments on the basis of their evidence for genoprotection, and further suggest that this approach may provide a viable therapeutic strategy for improving immunity in older people.

Metformin for Treatment of Acute COVID-19: Systematic Review of Clinical Trial Data Against SARS-CoV-2

BACKGROUND

Observational and preclinical data suggest metformin may prevent severe coronavirus disease 2019 (COVID-19) outcomes.

PURPOSE

We conducted a systematic review of randomized, placebo-controlled clinical trials of metformin treatment for COVID-19 to determine whether metformin affects clinical or laboratory outcomes in individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and present a structured summary of preclinical data.

STUDY SELECTION

Two independent reviewers searched PubMed, Scopus, Cochrane COVID-19 Study Register, and ClinicalTrials.gov on 1 February 2023 with no date restrictions for trials where investigators randomized adults with COVID-19 to metformin versus control and assessed clinical and/or laboratory outcomes of interest. The Cochrane Risk of Bias 2 tool was used to assess bias.

DATA EXTRACTION

Two reviewers extracted data pertaining to prespecified outcomes of each interest from each included trial.

DATA SYNTHESIS

The synthesis plan was developed a priori and was guided by Synthesis Without Meta-analysis (SWiM) guidelines. Summary tables and narrative synthesis were used (PROSPERO, 2022, CRD42022349896). Three randomized trials met inclusion criteria. In two of the trials investigators found that metformin improved clinical outcomes (prevented need for oxygen and prevented need for acute health care use), and in the third trial a larger portion of adults with diabetes were enrolled but results did show a direction of benefit similar to that of the other trials in the per-protocol group. In the largest trial, subjects were enrolled during the delta and omicron waves and vaccinated individuals were included. The certainty of evidence that metformin prevents health care use due to COVID-19 was moderate per Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. Many preclinical studies have shown metformin to be effective against SARS-CoV-2.

LIMITATIONS

Limitations include inclusion of only three trials and heterogeneity between trials.

CONCLUSIONS

Future trials will help define the role of metformin in COVID-19 treatment guidelines.

Clinically Evaluated COVID-19 Drugs with Therapeutic Potential for Biological Warfare Agents

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak resulted in hundreds of millions of coronavirus cases, as well as millions of deaths worldwide. Coronavirus Disease 2019 (COVID-19), the disease resulting from exposure to this pathogen, is characterized, among other features, by a pulmonary pathology, which can progress to "cytokine storm", acute respiratory distress syndrome (ARDS), respiratory failure and death. Vaccines are the unsurpassed strategy for prevention and protection against the SARS-CoV-2 infection. However, there is still an extremely high number of severely ill people from at-risk populations. This may be attributed to waning immune response, variant-induced breakthrough infections, unvaccinated population, etc. It is therefore of high importance to utilize pharmacological-based treatments, despite the progression of the global vaccination campaign. Until the approval of Paxlovid, an efficient and highly selective anti-SARS-CoV-2 drug, and the broad-spectrum antiviral agent Lagevrio, many pharmacological-based countermeasures were, and still are, being evaluated in clinical trials. Some of these are host-directed therapies (HDTs), which modulate the endogenic response against the virus, and therefore may confer efficient protection against a wide array of pathogens. These could potentially include Biological Warfare Agents (BWAs), exposure to which may lead to mass casualties due to disease severity and a possible lack of efficient treatment. In this review, we assessed the recent literature on drugs under advanced clinical evaluation for COVID-19 with broad spectrum activity, including antiviral agents and HDTs, which may be relevant for future coping with BWAs, as well as with other agents, in particular respiratory infections.

A pilot metabolomic study of drug interaction with the immune response to seasonal influenza vaccination

Many human diseases, including metabolic diseases, are intertwined with the immune system. The understanding of how the human immune system interacts with pharmaceutical drugs is still limited, and epidemiological studies only start to emerge. As the metabolomics technology matures, both drug metabolites and biological responses can be measured in the same global profiling data. Therefore, a new opportunity presents itself to study the interactions between pharmaceutical drugs and immune system in the high-resolution mass spectrometry data. We report here a double-blinded pilot study of seasonal influenza vaccination, where half of the participants received daily metformin administration. Global metabolomics was measured in the plasma samples at six timepoints. Metformin signatures were successfully identified in the metabolomics data. Statistically significant metabolite features were found both for the vaccination effect and for the drug-vaccine interactions. This study demonstrates the concept of using metabolomics to investigate drug interaction with the immune response in human samples directly at molecular levels.

Aging and chronic inflammation: highlights from a multidisciplinary workshop

Aging is a gradual, continuous series of natural changes in biological, physiological, immunological, environmental, psychological, behavioral, and social processes. Aging entails changes in the immune system characterized by a decrease in thymic output of naïve lymphocytes, an accumulated chronic antigenic stress notably caused by chronic infections such as cytomegalovirus (CMV), and immune cell senescence with acquisition of an inflammatory senescence-associated secretory phenotype (SASP). For this reason, and due to the SASP originating from other tissues, aging is commonly accompanied by low-grade chronic inflammation, termed "inflammaging". After decades of accumulating evidence regarding age-related processes and chronic inflammation, the domain now appears mature enough to allow an integrative reinterpretation of old data. Here, we provide an overview of the topics discussed in a recent workshop "Aging and Chronic Inflammation" to which many of the major players in the field contributed. We highlight advances in systematic measurement and interpretation of biological markers of aging, as well as their implications for human health and longevity and the interventions that can be envisaged to maintain or improve immune function in older people.

The effect of metformin on influenza vaccine responses in nondiabetic older adults: a pilot trial

BACKGROUND

Aging is associated with progressive declines in immune responses leading to increased risk of severe infection and diminished vaccination responses. Influenza (flu) is a leading killer of older adults despite availability of seasonal vaccines. Geroscience-guided interventions targeting biological aging could offer transformational approaches to reverse broad declines in immune responses with aging. Here, we evaluated effects of metformin, an FDA approved diabetes drug and candidate anti-aging drug, on flu vaccination responses and markers of immunological resilience in a pilot and feasibility double-blinded placebo-controlled study.

RESULTS

Healthy older adults (non-diabetic/non-prediabetic, age: 74.4 ± 1.7 years) were randomized to metformin (n = 8, 1500 mg extended release/daily) or placebo (n = 7) treatment for 20 weeks and were vaccinated with high-dose flu vaccine after 10 weeks of treatment. Peripheral blood mononuclear cells (PBMCs), serum, and plasma were collected prior to treatment, immediately prior to vaccination, and 1, 5, and 10 weeks post vaccination. Increased serum antibody titers were observed post vaccination with no significant differences between groups. Metformin treatment led to trending increases in circulating T follicular helper cells post-vaccination. Furthermore, 20 weeks of metformin treatment reduced expression of exhaustion marker CD57 in circulating CD4 T cells.

CONCLUSIONS

Pre-vaccination metformin treatment improved some components of flu vaccine responses and reduced some markers of T cell exhaustion without serious adverse events in nondiabetic older adults. Thus, our findings highlight the potential utility of metformin to improve flu vaccine responses and reduce age-related immune exhaustion in older adults, providing improved immunological resilience in nondiabetic older adults.

Mechanisms of ageing: growth hormone, dietary restriction, and metformin

Tackling the mechanisms underlying ageing is desirable to help to extend the duration and improve the quality of life. Life extension has been achieved in animal models by suppressing the growth hormone-insulin-like growth factor 1 (IGF-1) axis and also via dietary restriction. Metformin has become the focus of increased interest as a possible anti-ageing drug. There is some overlap in the postulated mechanisms of how these three approaches could produce anti-ageing effects, with convergence on common downstream pathways. In this Review, we draw on evidence from both animal models and human studies to assess the effects of suppression of the growth hormone-IGF-1 axis, dietary restriction, and metformin on ageing.

An Examination of Whether Diabetes Control and Treatments Are Associated With Change in Frailty Index Across 8 Years: An Ancillary Exploratory Study From the Action for Health in Diabetes (Look AHEAD) Trial

OBJECTIVE

The aim of this study was to describe cross-sectional and longitudinal associations between glycated hemoglobin (HbA1c) levels and strategies to control type 2 diabetes with baseline levels and 8-year changes in a deficit accumulation frailty index (FI), a commonly used marker of biological aging.

RESEARCH DESIGN AND METHODS

We conducted exploratory analyses from 4,169 participants, aged 45-76 years, who were followed in the Action for Health in Diabetes (Look AHEAD) randomized controlled clinical trial, pooling data across intervention groups. We related baseline and 8-year levels of HbA1c with FI scores using analyses of variance and covariance. Associations between 8-year changes in FI and the use of diabetes medication classes and weight changes were assessed with control for HbA1c levels. Inverse probability weighting was used to assess bias associated with differential follow-up.

RESULTS

Baseline and average HbA1c levels over time of <7%, as compared with ≥8%, were associated with less increase in FI scores over 8 years (both P ≤ 0.002). After adjustment for HbA1c, use of metformin and weight loss >5% were independently associated with slower increases in frailty.

CONCLUSIONS

Lower HbA1c levels among individuals with diabetes are associated with slower biological aging as captured by a deficit accumulation FI. Strategies to control diabetes through weight loss or metformin use may also slow aging.

Current Challenges and Solutions for Clinical Management and Care of People with HIV: Findings from the 12th Annual International HIV and Aging Workshop

People with HIV on combination antiretroviral therapy (ART) have longer life expectancy and are increasingly experiencing age-related comorbidities. Thus, aging with HIV has become a central issue in clinical care and research, which has been particularly challenging with the intersection of the ongoing coronavirus (COVID)-19 pandemic. Since 2009, the International Workshop on HIV and Aging has served as a multidisciplinary platform to share research findings from cross-disciplinary fields along with community advocates to address critical issues in HIV and aging. In this article, we summarize the key oral presentations from the 12th Annual International Workshop on HIV and Aging, held virtually on September 23rd and 24th, 2021. The topics ranged from basic science research on biological mechanisms of aging to quality of life and delivery of care under the COVID-19 pandemic. This workshop enriched our understanding of HIV and aging under the COVID-19 pandemic, identified challenges and opportunities to combat the impact of COVID-19 on HIV communities, and also provided updated research and future directions of the field to move HIV and aging research forward, with the ultimate goal of successful aging for older people with HIV.

Crosstalk between SARS-CoV-2 Infection and Type II Diabetes

Since the outbreak of coronavirus disease (COVID-19) in Wuhan, China, triggered by severe acute respiratory coronavirus 2 (SARS-CoV-2) in late November 2019, spreading to more than 200 countries of the world, the ensuing pandemic to an enormous loss of lives, mainly the older population with comorbidities, like diabetes, cardiovascular disease, chronic obstructive pulmonary disease, obesity, and hypertension. Amongst these immune-debilitating diseases, SARS-CoV-2 infection is the most common in patients with diabetes due to the absence of a normal active immune system to fight the COVID-19. Recovery of patients having a history of diabetes from COVID-19 encounters several complications, and their management becomes cumbersome. For control of coronavirus, antiviral medications, glucose-lowering agents, and steroids have been carefully evaluated. In the present review, we discuss the crosstalk between SARS-CoV-2 infection and patients with a history of diabetes. We mainly emphasize the molecular factors that are involved in diabetic individuals recently infected by SARS-CoV-2 and developed COVID-19 disease. Lastly, we examine the medications available for the long-term management of diabetic patients with SARS-CoV-2 infection.

Lymphocyte and dendritic cell response to a period of intensified training in young healthy humans and rodents: A systematic review and meta-analysis

Background: Intensified training coupled with sufficient recovery is required to improve athletic performance. A stress-recovery imbalance can lead to negative states of overtraining. Hormonal alterations associated with intensified training, such as blunted cortisol, may impair the immune response. Cortisol promotes the maturation and migration of dendritic cells which subsequently stimulate the T cell response. However, there are currently no clear reliable biomarkers to highlight the overtraining syndrome. This systematic review and meta-analysis examined the effect of intensified training on immune cells. Outcomes from this could provide insight into whether these markers may be used as an indicator of negative states of overtraining. Methods: SPORTDiscus, PUBMED, Academic Search Complete, Scopus and Web of Science were searched until June 2022. Included articles reported on immune biomarkers relating to lymphocytes, dendritic cells, and cytokines before and after a period of intensified training, in humans and rodents, at rest and in response to exercise. Results: 164 full texts were screened for eligibility. Across 57 eligible studies, 16 immune biomarkers were assessed. 7 were assessed at rest and in response to a bout of exercise, and 9 assessed at rest only. Included lymphocyte markers were CD3⁺, CD4⁺ and CD8⁺ T cell count, NK cell count, NK Cytolytic activity, lymphocyte proliferation and CD4/CD8 ratio. Dendritic cell markers examined were CD80, CD86, and MHC II expression. Cytokines included IL-1β, IL-2, IL-10, TNF-α and IFN-γ. A period of intensified training significantly decreased resting total lymphocyte (d= -0.57, 95% CI -0.30) and CD8⁺ T cell counts (d= -0.37, 95% CI -0.04), and unstimulated plasma IL-1β levels (d= -0.63, 95% CI -0.17). Resting dendritic cell CD86 expression significantly increased (d = 2.18, 95% CI 4.07). All other biomarkers remained unchanged. Conclusion: Although some biomarkers alter after a period of intensified training, definitive immune biomarkers are limited. Specifically, due to low study numbers, further investigation into the dendritic cell response in human models is required.

Epidemiology and Clinical Outcomes of HIV Infection in South-Central China: A Retrospective Study From 2003 to 2018

Objective

HIV epidemiology in South-Central China is rarely reported. This study aims to characterize epidemiological and clinical features of HIV-infected patients in Hunan Province, located in South-Central China, for better management of HIV infections.

Methods

This retrospective study retrieved multi-center records of laboratory-confirmed HIV-infected patients in Hunan province. Information on HIV-associated mortality and antiretroviral therapies was also collected.

Results

Among 34,297 patients diagnosed with HIV infections from 2003 to 2018, 73.9% were males, 41.3% were older adults (≥50 years), and 71.2% were infected by heterosexual transmission. Despite a slow growth of new HIV infections in the overall population, annual percentages of HIV infections increased in older males (85.3% through heterosexual transmission) and young patients <30 years (39.9% through homosexual transmission). At baseline, serum levels of CD4+ T-cell counts were lower in older adults (191.0 cells/μl) than in young patients (294.6 cells/μl, p-value < 0.0001). A large proportion (47.2%, N = 16,165) of HIV-infected patients had advanced HIV disease (CD4+ T-cell counts < 200 cells/μl) from 2003 to 2018. All-cause mortality (57.0% due to AIDS-related illnesses) was reported among 4411 HIV-infected patients, including 2619 older adults. The 10-year survival rate was significantly lower in elderly males than in other patients (59.0 vs. 78.4%, p-value < 0.05).

Conclusions

Elderly males are prone to HIV infections with a high risk of HIV-associated fatality. Our findings support early prevention and critical care for elderly populations to control HIV infections.

Comorbidities and increased mortality of COVID-19 among the elderly: A systematic review

Purpose

The purpose of current review is to conduct a systematic overview of articles published between 2019 and 2021 on the relationship of comorbidities and mortality due to Coronavirus Disease 2019 (COVID-19) among the elderly population.

Methods

We conducted a systematic search on PubMed for articles published between 2019 and 2021 to identify any cohort and case-control studies that investigated the relationship of comorbidities and COVID-19 mortality among the elderly, defined as 60 years of age and above. Databases were searched independently by two authors. Disagreements were resolved by the inclusion of a third investigator. Reviews, systematic reviews, and meta-analyses were excluded from our systematic review.

Results

A total of 15 studies were selected for our systematic review. Of the included studies, 3 were case-control, 3 were prospective cohort studies and 9 were retrospective cohort studies. As for size, 10 studies were conducted on populations of <1000 participants, 3 ranging from 1001 to 10,000, and 2 on populations of >10,000 individuals. The included studies found that the presence of certain conditions, such as cardiovascular, respiratory, renal diseases, malignancies, diseases of the nervous system and diabetes are associated to increased mortality in populations that consisted of elderly patients.

Conclusion

Results of our systematic review suggest that comorbidities contribute to increased COVID-19 mortality among the elderly. The detrimental effect of comorbidities and advanced age on the immune response could lead to a more frequent occurrence of symptomatic and severe infections with COVID-19.

Diabetic patients treated with metformin during early stages of Alzheimer's disease show a better integral performance: data from ADNI study

We evaluated the effect of the antidiabetic drug metformin on patients enrolled in the ADNI study considering patients with mild cognitive impairment (MCI) due to Alzheimer's disease (AD). Employing data from this observational study, we performed a principal component analysis focusing on the cognitive sphere by evaluating data from neuropsychological tests included in a modified version of the Alzheimer's Disease Cooperative Study-Preclinical Alzheimer Cognitive Composite (ADCS-PACC). Second, we included the levels of amyloid-β, tau, and phosphorylated tau in CSF. We found that MCI metformin-treated patients were globally characterized as subjects with a better cognitive performance and CSF biomarkers profile than the mean population of MCI patients. On the other hand, control subjects and type 2 diabetes patients (T2D) were paired by age, gender, ApoE allele, and years of education, defining three groups: MCI, MCI + T2D, and MCI + T2D + metformin. We evaluated the effect of T2D and metformin treatment employing the PACC score and composites defined from standardized ADNI variables to evaluate the memory and learning function. We found that MCI + T2D patients had a worse cognitive performance than MCI patients, but this deleterious effect was not observed in MCI + T2D + metformin patients. These cognitive variations were associated with changes in cortical thickness and hippocampal volume. Finally, no differences were found in metabolic plasmatic parameters (glycemia, cholesterol, triglycerides). Our study-employing different strategies for data analysis from the global study ADNI-shows a beneficial effect of metformin treatment on cognitive performance, CSF biomarkers profile, and neuroanatomical measures in MCI due to AD patients.

Chronic HIV Infection and Aging: Application of a Geroscience-Guided Approach

ABSTRACT

The ability of virally suppressive antiretroviral therapy use to extend the life span of people with HIV (PWH) implies that the age of PWH will also increase. Among PWH, extended survival comes at a cost of earlier onset and increased rates of aging-associated comorbidities and geriatric syndromes, with persistent inflammation and immune dysregulation consequent to chronic HIV infection and to antiretroviral therapy use contributing to an overall decrease in health span. The geroscience hypothesis proposes that the root causes of most aging-related chronic diseases and conditions is the aging process itself. Hence, therapeutically targeting fundamental aging processes could have a greater impact on alleviating or delaying aging-associated comorbidities than addressing each disease individually. Extending the geroscience hypothesis to PWH, we speculate that targeting basic mechanisms of aging will improve overall health with age. Clinical features and pathophysiologic mechanisms of chronic diseases in PWH qualitatively resemble those seen in older adults without HIV. Therefore, drugs that target any of the pillars of aging, including metformin, rapamycin, and nicotinamide adenine dinucleotide precursors, may also slow the rate of onset of age-associated comorbidities and geriatric syndromes in PWH. Drugs that selectively induce apoptosis of senescent cells, termed senolytics, may also improve health span among PWH. Preliminary evidence suggests that senescent cell burden is increased in PWH, implying that senescent cells are an excellent therapeutic target for extending health span. Recently initiated clinical trials evaluating senolytics in age-related diseases offer insights into the design and potential implementation of similar trials for PWH.

Extending human healthspan and longevity: a symposium report

For many years, it was believed that the aging process was inevitable and that age-related diseases could not be prevented or reversed. The geroscience hypothesis, however, posits that aging is, in fact, malleable and, by targeting the hallmarks of biological aging, it is indeed possible to alleviate age-related diseases and dysfunction and extend longevity. This field of geroscience thus aims to prevent the development of multiple disorders with age, thereby extending healthspan, with the reduction of morbidity toward the end of life. Experts in the field have made remarkable advancements in understanding the mechanisms underlying biological aging and identified ways to target aging pathways using both novel agents and repurposed therapies. While geroscience researchers currently face significant barriers in bringing therapies through clinical development, proof-of-concept studies, as well as early-stage clinical trials, are underway to assess the feasibility of drug evaluation and lay a regulatory foundation for future FDA approvals in the future.

Outcome and death risk of diabetes patients with Covid-19 receiving pre-hospital and in-hospital metformin therapies

BACKGROUND

COVID-19 has stroke Brazil harshly, deaths by COVID-19 in Brazil represent almost 13% of the total deaths by COVID-19 in the world, even though Brazilian population represents only 2.6% of the world population. Our aim in this study was to evaluate death and intubation outcomes and risk factors associated with COVID-19, and treatment options focusing on diabetes patients and the use of metformin pre-admission and during hospitalization.

METHODS

In this Brazilian single-center study we evaluated 1170 patients hospitalized due to COVID-19. Diabetes patients (n = 188) were divided based on their use of pre-hospital and in-hospital metformin (non-met-group and met-group).

RESULTS

In the total cohort most comorbidities were risk factors for orotracheal intubation and death. The use of chloroquine/hydroxychloroquine was significantly associated with increased death and intubation risk in uni- and multivariate analysis. Diabetes patients showed worst clinical feature compared with non-diabetes patients. In-hospital non-met-group had increased mortality (20.5%) compared to met-group (3.5%) (p = 0.0002) and univariable cox proportion hazard regression indicated in-hospital metformin reduced mortality (HR = 0.325, p = 0.035). Patients that used pre-hospital metformin showed lower severity parameters at hospital admission. (met-group: 2.45 ± 2.5; non-met-group: 4.25 ± 3.4). In all the groups older patients showed more severe clinical conditions and high risk of death and intubation.

CONCLUSION

Even though this is a single-center study, results from other reports have shown a similar trend, indicating that patients that used metformin during hospitalization have a better prognosis and reduced risk of death.

Network Topology of Biological Aging and Geroscience-Guided Approaches to COVID-19

Aging has emerged as the greatest and most prevalent risk factor for the development of severe COVID-19 infection and death following exposure to the SARS-CoV-2 virus. The presence of multiple co-existing chronic diseases and conditions of aging further enhances this risk. Biological aging not only enhances the risk of chronic diseases, but the presence of such conditions further accelerates varied biological processes or "hallmarks" implicated in aging. Given growing evidence that it is possible to slow the rate of many biological aging processes using pharmacological compounds has led to the proposal that such geroscience-guided interventions may help enhance immune resilience and improve outcomes in the face of SARS-CoV-2 infection. Our review of the literature indicates that most, if not all, hallmarks of aging may contribute to the enhanced COVID-19 vulnerability seen in frail older adults. Moreover, varied biological mechanisms implicated in aging do not function in isolation from each other, and exhibit intricate effects on each other. With all of these considerations in mind, we highlight limitations of current strategies mostly focused on individual single mechanisms, and we propose an approach which is far more multidisciplinary and systems-based emphasizing network topology of biological aging and geroscience-guided approaches to COVID-19.

Metformin Protects against Radiation-Induced Acute Effects by Limiting Senescence of Bronchial-Epithelial Cells

Radiation-induced damage to normal lung parenchyma remains a dose-limiting factor in thorax-associated radiotherapy (RT). Severe early and late complications with lungs can increase the risk of morbidity in cancer patients after RT. Herein, senescence of lung epithelial cells following RT-induced cellular stress, or more precisely the respective altered secretory profile, the senescence-associated secretory phenotype (SASP), was suggested as a central process for the initiation and progression of pneumonitis and pulmonary fibrosis. We previously reported that abrogation of certain aspects of the secretome of senescent lung cells, in particular, signaling inhibition of the SASP-factor Ccl2/Mcp1 mediated radioprotection especially by limiting endothelial dysfunction. Here, we investigated the therapeutic potential of a combined metformin treatment to protect normal lung tissue from RT-induced senescence and associated lung injury using a preclinical mouse model of radiation-induced pneumopathy. Metformin treatment efficiently limited RT-induced senescence and SASP expression levels, thereby limiting vascular dysfunctions, namely increased vascular permeability associated with increased extravasation of circulating immune and tumor cells early after irradiation (acute effects). Complementary in vitro studies using normal lung epithelial cell lines confirmed the senescence-limiting effect of metformin following RT finally resulting in radioprotection, while fostering RT-induced cellular stress of cultured malignant epithelial cells accounting for radiosensitization. The radioprotective action of metformin for normal lung tissue without simultaneous protection or preferable radiosensitization of tumor tissue might increase tumor control probabilities and survival because higher radiation doses could be used.

Frailty and HIV: Moving from Characterization to Intervention

PURPOSE OF REVIEW

While the characteristics associated with frailty in people with HIV (PWH) have been well described, little is known regarding interventions to slow or reverse frailty. Here we review interventions to prevent or treat frailty in the general population and in people with HIV (PWH).

RECENT FINDINGS

Frailty interventions have primarily relied on nonpharmacologic interventions (e.g., exercise and nutrition). Although few have addressed frailty, many of these therapies have shown benefit on components of frailty including gait speed, strength, and low activity among PWH. When nonpharmacologic interventions are insufficient, pharmacologic interventions may be necessary. Many interventions have been tested in preclinical models, but few have been tested or shown benefit among older adults with or without HIV. Ultimately, pharmacologic and nonpharmacologic interventions have the potential to improve vulnerability that underlies frailty in PWH, though clinical data is currently sparse.

Atrial appendage angiotensin-converting enzyme-2, aging and cardiac surgical patients: a platform for understanding aging-related coronavirus disease-2019 vulnerabilities

PURPOSE OF REVIEW

Hospitalizations for COVID-19 dramatically increase with age. This is likely because of increases in fragility across biological repair systems and a weakened immune system, including loss of the cardiorenal protective arm of the renin--angiotensin system (RAS), composed of angiotensin-converting enzyme-2 (ACE2)/angiotensin-(1--7) [Ang-(1--7)] and its actions through the Mas receptor. The purpose of this review is to explore how cardiac ACE2 changes with age, cardiac diseases, comorbid conditions and pharmaceutical regimens in order to shed light on a potential hormonal unbalance facilitating SARs-CoV-2 vulnerabilities in older adults.

RECENT FINDINGS

Increased ACE2 gene expression has been reported in human hearts with myocardial infarction, cardiac remodeling and heart failure. We also found ACE2 mRNA in atrial appendage tissue from cardiac surgical patients to be positively associated with age, elevated by certain comorbid conditions (e.g. COPD and previous stroke) and increased in conjunction with patients' chronic use of antithrombotic agents and thiazide diuretics but not drugs that block the renin--angiotensin system.

SUMMARY

Cardiac ACE2 may have bifunctional roles in COVID-19 as ACE2 not only mediates cellular susceptibility to SARS-CoV-2 infection but also protects the heart via the ACE2/Ang-(1--7) pathway. Linking tissue ACE2 from cardiac surgery patients to their comorbid conditions and medical regimens provides a unique latform to address the influence that altered expression of the ACE2/Ang-(1-7)/Mas receptor axis might have on SARs-CoV-2 vulnerability in older adults.