Vitamin D3 replacement enhances antigen-specific immunity in older adults

Cutaneous adaptive immunity and uraemia: a narrative review

Chronic kidney disease affects 1 in 10 people globally, with a prevalence twenty times that of cancer. A subset of individuals will progress to end-stage renal disease (ESRD) where renal replacement therapy is required to maintain health. Cutaneous disease, including xerosis and pruritus, are endemic amongst patients with ESRD. In the uraemia-associated immune deficiency of ESRD, impaired circulating immune responses contribute to increased infection risk and poorer vaccination response. Clinical manifestations of dysregulated adaptive immunity within the skin have been well-described and have been posited to play a role in cutaneous features of ESRD. However, our understanding of the mechanisms by which adaptive immunity within the skin is affected by uraemia is relatively limited. We provide an overview of how the cutaneous adaptive immune system is impacted both directly and indirectly by uraemia, highlighting that much work has been extrapolated from the circulating immune system and often has not been directly evaluated in the skin compartment. We identify knowledge gaps which may be addressed by future research. Ultimately, greater understanding of these pathways may facilitate novel therapeutic approaches to ameliorate widespread cutaneous symptomatology in ESRD.

Vitamin D3 inhibits p38 MAPK and senescence-associated inflammatory mediator secretion by senescent fibroblasts that impacts immune responses during ageing

Vitamin D3 replacement in older insufficient adults significantly improves their antigen-specific varicella zoster virus (VZV) cutaneous immunity. However, the mechanisms involved in this enhancement of cutaneous immunity are not known. Here, we show for the first time that vitamin D3 blocks the senescence-associated secretory phenotype (SASP) production by senescent fibroblasts by partially inhibiting the p38 MAPK pathway. Furthermore, transcriptomic analysis of skin biopsies from older subjects after vitamin D3 supplementation shows that vitamin D3 inhibits the same inflammatory pathways in response to saline as the specific p38 inhibitor, losmapimod, which also enhances immunity in the skin of older subjects. Vitamin D3 supplementation therefore may enhance immunity during ageing in part by blocking p38 MAPK signalling and in turn inhibit SASP production from senescent cells in vivo.

[Immunonutrition and (its impact on) health. Micronutrients and debilitating factors]

Introduction

Introduction: the interaction between immunity and nutrition is complex and multifaceted. Micronutrients, including vitamins and minerals, are essential for immune function. In turn, immune function and lifestyle habits can affect nutritional needs and micronutrient utilization, creating an interdependence between nutrition and immunity that can be modulated by both external and internal factors. Objectives: to examine the relationship between micronutrient intake and immune function, and how debilitating factors such as aging, disease, and stress can impact this relationship. Methods: a review of scientific evidence and recommendations from major international scientific societies was conducted to identify the importance of micronutrients in immune function and how debilitating factors can alter their impact. Results: the effect of different micronutrients on immune function is described. Debilitating factors like aging, stress, and chronic diseases can compromise the immune system and make the body more susceptible to infections. However, adequate intake of micronutrients and healthy habits can help to strengthen immunity and mitigate the effects of these debilitating factors. Conclusion: immunonutrition is a critical component for maintaining a strong and healthy immune system. Sufficient intake of micronutrients and healthy lifestyle habits can help improve immunity, especially in the presence of debilitating factors.

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.

Vitamin D in the older population: a consensus statement

BACKGROUND

This paper reports results from the 5th International Conference "Controversies in Vitamin D" that was held in Stresa, Italy, 15-18 September 2021. The conference is part of this series that started in 2017 and has been conducted annually since. The objective of these conferences is to identify timely and controversial topics related to Vitamin D. Dissemination of the results of the conference through publications in peer-reviewed journals is an important means by which the most up to date information can be shared with physicians, investigators, and other health care professionals. Vitamin D and aging, the subject of this paper was featured at the conference.

METHODS

Participants were selected to review available literature on assigned topics related to vitamin D and aging and to present their findings with illustrative material, the intent of which was to stimulate discussion and to arrive at a consensus. The presentations were directed towards the following areas: impact of aging on vitamin D production and levels; skeletal effects of vitamin D deficiency in the older population; falls and vitamin D in the aging; potential extra skeletal effects of vitamin D; and strategies to prevent vitamin D deficiency. A final topic was related to how vitamin D might influence the efficacy of vaccines for Covid-19.

RESULTS

Hypovitaminosis D can lead to several skeletal and extra-skeletal outcomes. Older adults are at risk for vitamin D deficiency as both production and metabolism of vitamin D change with aging due to factors, such as reduced sun exposure and reduced production capacity of the skin. Skeletal consequences of these age-related changes can include reduced bone mineral density, osteomalacia and fractures. Potential extra-skeletal effects can include added risks for falls, reduced muscle strength, diabetes, cancer, and cardiovascular disease. Strategies to avoid these vitamin D deficiency-related negative outcomes include sun exposure, food fortification, and supplementation. While aging does not diminish sufficient reserve capacity for cutaneous vitamin D production, concerns about skin cancers and practical matters for the institutionalized elderly limit this option. Supplementation with vitamin D is the best option either pharmacologically or through food fortification. Regardless of treatment strategies, interventions to restore sufficient vitamin D status will show positive results only in those who are truly deficient. Thus, treatment goals should focus on avoiding 25(OH)D serum levels <30 nmol/l, with a goal to reach levels >50 nmol/l.

CONCLUSIONS

The results of this conference has led to consensus on several issues. Vitamin D supplementation should be combined with calcium to reduce fractures in the older population. The goal for adequate Vitamin D status should be to reach a serum level of 25(OH)D >50 nmol/l. It appears that daily low-dose vitamin D regimens reduce the risk of falling, especially in the elderly, compared with infrequent, large bolus doses that may increase it. The role of Vitamin D supplementation on muscle strength remains to be clarified. On the other hand, supplementation decreases the risk of progression to T2D from prediabetes among those who are Vitamin Ddeficient. Of three possible strategies to establish vitamin D sufficiency - sunshine exposure, food fortification, and supplementation - the latter seems to be the most effective and practical in the aging population.

Consensus and Controversial Aspects of Vitamin D and COVID-19

OBJECTIVES

This work aims to review and discuss controversial topics in the field of vitamin D, SARS-CoV-2 infection, and COVID-19.

PARTICIPANTS

The International Conferences "Controversies in Vitamin D" are a series of workshops that started in 2017 featuring international experts and leaders in vitamin D research and clinical practice. The 5th annual conference was held in Stresa, Italy, from 15 to 18 September 2021.

EVIDENCE

Before the event, participants reviewed available studies on their assigned topic, drafted a related abstract, and presented their findings at the time of the conference. Relevant literature that became available since was also discussed within the panel and updated accordingly.

CONSENSUS

Before the event, the drafted abstracts had been merged to prepare a preliminary document. After the conference presentations, in-depth discussions in open sessions led to consensus. The document was subsequently modified according to discussions and up-to-date literature inclusion.

CONCLUSIONS

There is quite consistent evidence for an association between low 25 OH vitamin D (25(OH)D) levels and poor COVID-19 outcomes, despite heterogeneous publications of variable quality. However, the low vitamin D status in COVID-19 patients might also reflect reverse causality. Vitamin D supplementation might have a positive role in COVID-19 prevention. The evidence supporting a beneficial effect of vitamin D treatment in decreasing the risk of COVID-19 complications is conflicting. Conclusive statement regarding the beneficial effect of vitamin D in this context await high-quality randomized controlled trials.

Vitamin D deficiency in British South Asians, a persistent but avoidable problem associated with many health risks (including rickets, T2DM, CVD, COVID-19 and pregnancy complications): the case for correcting this deficiency

High vitamin D deficiency rates, with rickets and osteomalacia, have been common in South Asians (SAs) arriving in Britain since the 1950s with preventable infant deaths from hypocalcaemic status-epilepticus and cardiomyopathy. Vitamin D deficiency increases common SA disorders (type 2 diabetes and cardiovascular disease), recent trials and non-linear Mendelian randomisation studies having shown deficiency to be causal for both disorders. Ethnic minority, obesity, diabetes and social deprivation are recognised COVID-19 risk factors, but vitamin D deficiency is not, despite convincing mechanistic evidence of it. Adjusting analyses for obesity/ethnicity abolishes vitamin D deficiency in COVID-19 risk prediction, but both factors lower serum 25(OH)D specifically. Social deprivation inadequately explains increased ethnic minority COVID-19 risks. SA vitamin D deficiency remains uncorrected after 70 years, official bodies using 'education', 'assimilation' and 'diet' as 'proxies' for ethnic differences and increasing pressures to assimilate. Meanwhile, English rickets was abolished from ~1940 by free 'welfare foods' (meat, milk, eggs, cod liver oil), for all pregnant/nursing mothers and young children (<5 years old). Cod liver oil was withdrawn from antenatal clinics in 1994 (for excessive vitamin A teratogenicity), without alternative provision. The take-up of the 2006 'Healthy-Start' scheme of food-vouchers for low-income families with young children (<3 years old) has been poor, being inaccessible and poorly publicised. COVID-19 pandemic advice for UK adults in 'lockdown' was '400 IU vitamin D/day', inadequate for correcting the deficiency seen winter/summer at 17.5%/5.9% in White, 38.5%/30% in Black and 57.2%/50.8% in SA people in representative UK Biobank subjects when recruited ~14 years ago and remaining similar in 2018. Vitamin D inadequacy worsens many non-skeletal health risks. Not providing vitamin D for preventing SA rickets and osteomalacia continues to be unacceptable, as deficiency-related health risks increase ethnic health disparities, while abolishing vitamin D deficiency would be easier and more cost-effective than correcting any other factor worsening ethnic minority health in Britain.

Determinants of Antibody Responses to SARS-CoV-2 Vaccines: Population-Based Longitudinal Study (COVIDENCE UK)

Antibody responses to SARS-CoV-2 vaccines vary for reasons that remain poorly understood. A range of sociodemographic, behavioural, clinical, pharmacologic and nutritional factors could explain these differences. To investigate this hypothesis, we tested for presence of combined IgG, IgA and IgM (IgGAM) anti-Spike antibodies before and after 2 doses of ChAdOx1 nCoV-19 (ChAdOx1, AstraZeneca) or BNT162b2 (Pfizer-BioNTech) in UK adults participating in a population-based longitudinal study who received their first dose of vaccine between December 2020 and July 2021. Information on sixty-six potential sociodemographic, behavioural, clinical, pharmacologic and nutritional determinants of serological response to vaccination was captured using serial online questionnaires. We used logistic regression to estimate multivariable-adjusted odds ratios (aORs) for associations between independent variables and risk of seronegativity following two vaccine doses. Additionally, percentage differences in antibody titres between groups were estimated in the sub-set of participants who were seropositive post-vaccination using linear regression. Anti-spike antibodies were undetectable in 378/9101 (4.2%) participants at a median of 8.6 weeks post second vaccine dose. Increased risk of post-vaccination seronegativity associated with administration of ChAdOx1 vs. BNT162b2 (adjusted odds ratio (aOR) 6.6, 95% CI 4.2−10.4), shorter interval between vaccine doses (aOR 1.6, 1.2−2.1, 6−10 vs. >10 weeks), poor vs. excellent general health (aOR 3.1, 1.4−7.0), immunodeficiency (aOR 6.5, 2.5−16.6) and immunosuppressant use (aOR 3.7, 2.4−5.7). Odds of seronegativity were lower for participants who were SARS-CoV-2 seropositive pre-vaccination (aOR 0.2, 0.0−0.6) and for those taking vitamin D supplements (aOR 0.7, 0.5−0.9). Serologic responses to vaccination did not associate with time of day of vaccine administration, lifestyle factors including tobacco smoking, alcohol intake and sleep, or use of anti-pyretics for management of reactive symptoms after vaccination. In a sub-set of 8727 individuals who were seropositive post-vaccination, lower antibody titres associated with administration of ChAdOx1 vs. BNT162b2 (43.4% lower, 41.8−44.8), longer duration between second vaccine dose and sampling (12.7% lower, 8.2−16.9, for 9−16 weeks vs. 2−4 weeks), shorter interval between vaccine doses (10.4% lower, 3.7−16.7, for <6 weeks vs. >10 weeks), receiving a second vaccine dose in October−December vs. April−June (47.7% lower, 11.4−69.1), older age (3.3% lower per 10-year increase in age, 2.1−4.6), and hypertension (4.1% lower, 1.1−6.9). Higher antibody titres associated with South Asian ethnicity (16.2% higher, 3.0−31.1, vs. White ethnicity) or Mixed/Multiple/Other ethnicity (11.8% higher, 2.9−21.6, vs. White ethnicity), higher body mass index (BMI; 2.9% higher, 0.2−5.7, for BMI 25−30 vs. <25 kg/m2) and pre-vaccination seropositivity for SARS-CoV-2 (105.1% higher, 94.1−116.6, for those seropositive and experienced COVID-19 symptoms vs. those who were seronegative pre-vaccination). In conclusion, we identify multiple determinants of antibody responses to SARS-CoV-2 vaccines, many of which are modifiable.

Vitamin D Supplementation Does Not Influence SARS-CoV-2 Vaccine Efficacy or Immunogenicity: Sub-Studies Nested within the CORONAVIT Randomised Controlled Trial

Vitamin D deficiency has been reported to associate with the impaired development of antigen-specific responses following vaccination. We aimed to determine whether vitamin D supplements might boost the immunogenicity and efficacy of SARS-CoV-2 vaccination by conducting three sub-studies nested within the CORONAVIT randomised controlled trial, which investigated the effects of offering vitamin D supplements at a dose of 800 IU/day or 3200 IU/day vs. no offer on risk of acute respiratory infections in UK adults with circulating 25-hydroxyvitamin D concentrations <75 nmol/L. Sub-study 1 (n = 2808) investigated the effects of vitamin D supplementation on the risk of breakthrough SARS-CoV-2 infection following two doses of SARS-CoV-2 vaccine. Sub-study 2 (n = 1853) investigated the effects of vitamin D supplementation on titres of combined IgG, IgA and IgM (IgGAM) anti-Spike antibodies in eluates of dried blood spots collected after SARS-CoV-2 vaccination. Sub-study 3 (n = 100) investigated the effects of vitamin D supplementation on neutralising antibody and cellular responses in venous blood samples collected after SARS-CoV-2 vaccination. In total, 1945/2808 (69.3%) sub-study 1 participants received two doses of ChAdOx1 nCoV-19 (Oxford−AstraZeneca); the remainder received two doses of BNT162b2 (Pfizer). Mean follow-up 25(OH)D concentrations were significantly elevated in the 800 IU/day vs. no-offer group (82.5 vs. 53.6 nmol/L; mean difference 28.8 nmol/L, 95% CI 22.8−34.8) and in the 3200 IU/day vs. no offer group (105.4 vs. 53.6 nmol/L; mean difference 51.7 nmol/L, 45.1−58.4). Vitamin D supplementation did not influence the risk of breakthrough SARS-CoV-2 infection in vaccinated participants (800 IU/day vs. no offer: adjusted hazard ratio 1.28, 95% CI 0.89 to 1.84; 3200 IU/day vs. no offer: 1.17, 0.81 to 1.70). Neither did it influence IgGAM anti-Spike titres, neutralising antibody titres or IFN-γ concentrations in the supernatants of S peptide-stimulated whole blood. In conclusion, vitamin D replacement at a dose of 800 or 3200 IU/day effectively elevated 25(OH)D concentrations, but it did not influence the protective efficacy or immunogenicity of SARS-CoV-2 vaccination when given to adults who had a sub-optimal vitamin D status at baseline.

Micronutrients to Support Vaccine Immunogenicity and Efficacy

The world has entered the third year of the coronavirus disease 2019 (COVID-19) pandemic. Vaccination is the primary public health strategy to protect against infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in addition to other measures, such as mask wearing and social distancing. Vaccination has reduced COVID-19 severity and mortality dramatically. Nevertheless, incidence globally remains high, and certain populations are still at risk for severe outcomes. Additional strategies to support immunity, including potentially enhancing the response to vaccination, are needed. Many vitamins and trace minerals have recognized immunomodulatory actions, and their status and/or supplementation have been reported to correspond to the incidence and severity of infection. Furthermore, a variety of observational and some interventional studies report that adequate micronutrient status or micronutrient supplementation is associated with enhanced vaccine responses, including to COVID-19 vaccination. Such data suggest that micronutrient supplementation may hold the potential to improve vaccine immunogenicity and effectiveness, although additional interventional studies to further strengthen the existing evidence are needed. Positive findings from such research could have important implications for global public health, since deficiencies in several micronutrients that support immune function are prevalent in numerous settings, and supplementation can be implemented safely and inexpensively.

Triple jeopardy in ageing: COVID-19, co-morbidities and inflamm-ageing

Covid-19 endangers lives, has disrupted normal life, changed the way medicine is practised and is likely to alter our world for the foreseeable future. Almost two years on since the presumptive first diagnosis of COVID-19 in China, more than two hundred and fifty million cases have been confirmed and more than five million people have died globally, with the figures rising daily. One of the most striking aspects of COVID-19 illness is the marked difference in individuals' experiences of the disease. Some, most often younger groups, are asymptomatic, whereas others become severely ill with acute respiratory distress syndrome (ARDS), pneumonia or proceed to fatal organ disease. The highest death rates are in the older and oldest age groups and in people with co-morbidities such as diabetes, heart disease and obesity. Three major questions seem important to consider. What do we understand about changes in the immune system that might contribute to the older person's risk of developing severe COVID-19? What factors contribute to the higher morbidity and mortality in older people with COVID-19? How could immunocompetence in the older and the frailest individuals and populations be supported and enhanced to give protection from serious COVID-19 illness?

Extreme immunotherapy: emergency immunology to defeat pandemics

The ongoing global COVID-19 pandemic has thrown into sharp relief the gap between modern biology's ability to investigate and respond to a novel pathogen and modern medicine's ability to marshal effective front-line interventions to limit its immediate health impact. While we have witnessed the rapid development of innovative vaccines against SARS-CoV-2 using novel molecular platforms, these have yet to alter the pandemic's long-term trajectory in all but a handful of high-income countries. Health workers at the clinical front lines have little more in their clinical armamentarium than was available a century ago-chiefly oxygen and steroids-and yet advances in modern immunology and immunotherapeutics suggest an underuse of extant and effective, if unorthodox, therapies, which we now call "Extreme Immunotherapies for Pandemics (EIPs)."

Insights Into the Effects of Mucosal Epithelial and Innate Immune Dysfunction in Older People on Host Interactions With Streptococcus pneumoniae

In humans, nasopharyngeal carriage of Streptococcus pneumoniae is common and although primarily asymptomatic, is a pre-requisite for pneumonia and invasive pneumococcal disease (IPD). Together, these kill over 500,000 people over the age of 70 years worldwide every year. Pneumococcal conjugate vaccines have been largely successful in reducing IPD in young children and have had considerable indirect impact in protection of older people in industrialized country settings (herd immunity). However, serotype replacement continues to threaten vulnerable populations, particularly older people in whom direct vaccine efficacy is reduced. The early control of pneumococcal colonization at the mucosal surface is mediated through a complex array of epithelial and innate immune cell interactions. Older people often display a state of chronic inflammation, which is associated with an increased mortality risk and has been termed 'Inflammageing'. In this review, we discuss the contribution of an altered microbiome, the impact of inflammageing on human epithelial and innate immunity to S. pneumoniae, and how the resulting dysregulation may affect the outcome of pneumococcal infection in older individuals. We describe the impact of the pneumococcal vaccine and highlight potential research approaches which may improve our understanding of respiratory mucosal immunity during pneumococcal colonization in older individuals.