Anti-age Dietary Supplements in Healthy Older Adults: the proBNPage Reduction Trial

1. Background

Human life is relatively long so that, to assess the effect of any treatment on longevity, similarly long studies are needed. In addition, to demonstrate significant reductions in mortality, large samples are needed too. Thus, even though several promising treatments have been found in animal models, evidence of efficacy in humans has not come yet.

In an attempt to overcome these difficulties, several indicators of biological age have been proposed. Biological age may be defined as a measure, more reliable than chronological age, of how close to death an individual is. If such an indicator were available, assessing the efficacy of possible treatments would be relatively easy: one or two years of follow-up in relatively small groups might be sufficient to ascertain the arrest or even the inversion of the rise of the indicator.

In 2020 the authors proposed a new simple method to estimate a surrogate of biological age, the "proBNPage", starting from a single laboratory variable, NT-proBNP (the N-terminal fragment of type-B natriuretic peptide precursor). NT-proBNP is easily measurable in most laboratories. It is commonly used as a marker of heart failure, as it is released from the ventricular and atrial myocardium undergoing mechanical or ischemic stress. Several studies (both cross-sectional and longitudinal) have shown that this marker progressively increases with age. It is a good indicator of the risk of death even in subjects without cardiovascular diseases and, in particular, the authors have shown that NT-proBNP is associated with cardiovascular and all-cause mortality more strongly than chronological age. In addition, NT-proBNP is correlated with chronological age more strongly than all the main laboratory variables that had previously been proposed as biomarkers of biological age (as shown by the authors and subsequently also by others). Thus, starting from the equations of the regression lines of chronological age with NT-proBNP, the authors obtained two simple formulas, one for each sex, which allow the calculation of "proBNPage", in years, from the blood concentration of NT-proBNP.

Besides total and cardiovascular mortality, the authors have shown that other indicators of aging are independently associated with proBNPage, such as disease count, walking problems, the fitness assessed with a two-step test and the self-assessment of health status, in addition to previous myocardial infarction, previous stroke, peripheral artery disease and previous arterial revascularizations. Furthermore, in a recent study by other investigators, among more than 35000 clinical and laboratory biomarkers obtained from genomic, proteomic and metabolomic data in 4 cohorts of European populations, NT-proBNP was the marker most strongly associated with frailty in subjects without disability. Finally, in an older adult population, a further recent study has shown that NT-proBNP was the only independent risk factor of reduced intrinsic capacity among 20 laboratory variables, being associated with locomotion, hearing and vision disturbances and with some characteristic psychological aspects of aging.

To test, for the first time, the possible practical use of proBNPage, the authors have designed a study aimed at assessing the effects induced on it by a series of anti-age dietary supplements, which in previous studies have provided interesting results. For the choice of the treatments, the authors have sought the best compromise among available scientific evidence, safety and ease of obtaining the substances on the market.

Coenzyme Q10 (CoQ10): it is the only antioxidant that has been demonstrated to reduce cardiovascular mortality, in combination with selenium, in a sample of general population.

Selenium: selenoproteins contribute to the antioxidant systems of our organism. In addition, selenium has anti-inflammatory effects and is involved in the metabolism of thyroid hormones.

Resveratrol: powerful antioxidant, possible telomerase activator and inhibitor of the target of rapamycin (TOR) system.

TA-65: telomerase activator derived from Astragalus Membranaceus with proven capacity to lengthen telomeres in humans.

1. Study description

Design: Double-blind clinical trial with stratified randomization into 3 treatment groups (one placebo group and two food supplement-treated groups)

Primary objective: To describe, in the context of a longitudinal study lasting 2 years, the spontaneous trend of proBNPage in the placebo group, in order to find the parameters (time to reach a significant increase, magnitude of the increase and its variability) useful for planning future studies on anti-aging treatments.

Secondary objective: To describe, with pilot study, the potential of the proposed treatments to limit the progression of proBNPage, over the 2 years of study, compared to what is observed in the placebo group, to explore the feasibility and organizational needs of future multicenter trials on anti-aging treatments.

Study duration: 2 years

Sample size: 3 groups of 40 subjects each = 120 subjects

Non-institutionalized healthy elderly volunteers of both sexes will be included in the study. Their names and addresses will be obtained from lists provided by the public health service, including subjects aged 65-80 years, taking no more than 4 drugs a day and without recent (< 3 years) hospital admissions. By random choice, 2000 subjects with the above characteristics will receive a letter with the invitation to participate, together with a short questionnaire for preliminary health status assessment. For acceptation, the volunteers will return the compiled questionnaire by mail. Five hundred are expected to respond and, according to the information provided with the questionnaires, 200 of them will be selected (see inclusion and exclusion criteria) and summoned by phone for the first visit.

Screening assessment (Visit 1) After signing the informed consent, the subjects willing to participate will undergo anamnestic investigation (previous diseases, life habits, basal activities of daily living (ADL), instrumental activities of daily living (IADL), risk factors and medications taken, with all available documentation checked), medical examination (with weight, height, blood pressure and oxygen saturation), ECG and fasting venous blood sampling (for complete blood count, total cholesterol, HDL cholesterol, triglycerides, creatinine, Na, K, Ca, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, gamma glutamyl transpeptidase, creatine phosphokinase, erythrocyte sedimentation rate, C-reactive protein, blood glucose, glycated hemoglobin, international normalized ratio, activated partial thromboplastin time, and (in men) total and free prostate-specific antigen). According to the inclusion and exclusion criteria, 120 subjects will be selected to be randomized.

Randomization

The 120 selected patients will be subdivided into 4 strata with the following characteristics:

Men with age >= the median age of men

Men with age < the median age of men

Women with age >= the median age of women

Women with age < the median age of women

Using randomization lists, the subjects belonging to each stratum will be equally distributed among the 3 treatment groups, so that relevant casual displacements of age and sex among the groups will be avoided.

Baseline assessment (Visit 2) The selected subjects will undergo venous blood sampling for NT-proBNP measurement. This will be performed by fluorescence immune assay, using commercially available kits (Quidel).

Subsequent assessments: Visit 3: 14 days - Visit 4: 3 months - Visit 5: 6 months - Visit 6: 12 months - Visit 7: 18 months - Visit 8: 24 months.

Scheduled activities

Verification of safety of dietary supplements with: a) questionnaire for possible adverse reactions (all Visits); b) blood tests (like at Visit 1), ECG, body weight, blood pressure and oxygen saturation (Visits 1,3,4,6,8).

Longitudinal changes of proBNPage, with measurement of NT-proBNP (Visits 2,5,6,7,8).

Assessment of possible effects of dietary supplements on functional frailty indicators: a) Step test; b ) Handgrip; c) Euro QoL-5 Dimension questionnaire (Visits 2,5,6,7,8).

Every 6 months, handing of treatment boxes, collection of previous packages and check of treatments really taken (Visits 2,5,6,7,8).

Verification of possible adverse events, intervened diseases or variations of therapy and search for causes of possible deaths (all Visits)

1. Statistical analysis

Sample size was calculated with the goal of having, in repeated measures ANOVA, a probability of first type error < 0.05 and a probability of second type error < 0.20 (power 0.80). Using parameters obtained in our previous studies, the minimum size for each group was 9 (for between-within interaction). To account for probable dropouts, and to allow possible subgroup analysis, a fourfold sample will be opportune, that is, with 40 subjects per group.

Statistical procedures The primary objective of the study (establishing the time to reach a significant increase of proBNPage, the magnitude of the increase and its variability) requires the comparison, with Student's t for paired data, of proBNPage values at Visits 5 (6 months), 6 (12 months), 7 (18 months) and 8 (24 months) with the value at Visit 2 (baseline) in the placebo group.

The effects of treatments will be assessed considering both the completed cases and an intention-to-treat model. The variations (delta) of proBNPage within groups will be compared between groups by repeated measures ANOVA, with reference to the "between-within interaction". Two-tailed tests will be performed throughout, and P values < 0.05 will be considered significant.