Activation of telomerase by TA-65 enhances immunity and reduces inflammation post myocardial infarction

Abstract

Myocardial infarction (MI) accelerates immune ageing characterised by lymphopenia, expansion of terminally differentiated CD8⁺ T-lymphocytes (CD8⁺ T_EMRA) and inflammation. Pre-clinical data showed that TA-65, an oral telomerase activator, reduced immune ageing and inflammation after MI. We conducted a double blinded randomised controlled pilot trial evaluating the use of TA-65 to reduce immune cell ageing in patients following MI. Ninety MI patients aged over 65 years were randomised to either TA-65 (16 mg daily) or placebo for 12 months. Peripheral blood leucocytes were analysed by flow cytometry. The pre-defined primary endpoint was the proportion of CD8⁺ T-lymphocytes which were CD8⁺ T_EMRA after 12 months. Secondary outcomes included high-sensitivity C-reactive protein (hsCRP) levels. Median age of participants was 71 years. Proportions of CD8⁺ T_EMRA did not differ after 12 months between treatment groups. There was a significant increase in mean total lymphocyte count in the TA-65 group after 12 months (estimated treatment effect: + 285 cells/μl (95% CI: 117-452 cells/ μ l, p < 0.004), driven by significant increases from baseline in CD3⁺, CD4⁺, and CD8⁺ T-lymphocytes, B-lymphocytes and natural killer cells. No increase in lymphocyte populations was seen in the placebo group. At 12 months, hsCRP was 62% lower in the TA-65 group compared to placebo (1.1 vs. 2.9 mg/L). Patients in the TA-65 arm experienced significantly fewer adverse events (130 vs. 185, p = 0.002). TA-65 did not alter CD8⁺ T_EMRA but increased all major lymphocyte subsets and reduced hsCRP in elderly patients with MI after 12 months.

Keywords: Acute myocardial infarction; Ageing; Immunosenescence; T-lymphocytes; Telomerase.

Fig. 1

Gating of main leukocyte populations with TruCount assay. Flow cytometric analysis of a representative patient from the TACTIC trial is shown. At first, lymphocytes, monocytes, neutrophils, and beads were gated in SSC-Area against the leukocyte marker CD45. Lymphocytes were sequentially gated into CD3⁺ (T cells) and CD3⁻ cells. CD4⁺ and CD8⁺ T cells were gated from CD3 + cells, while B cells (CD19⁺) and natural killer cells (CD19⁻CD16⁺CD56⁺) were gated from CD3⁻ cells. Several sub-gates were sequentially gated from the main monocyte population to ensure that gating was performed on specific CD3⁻CD4⁺CD19⁻CD45⁺ cells. Finally, monocytes were divided into classical (CLA), intermediate (INT), or non-classical monocytes (NON CLA) based on the abundance of CD16 expression

Fig. 2

Consolidated Standards of Reporting Trials (CONSORT) diagram of patient enrolment. The diagram shows the number of patients who met the inclusion or exclusion criteria and their distribution among the two study groups. TA-65 and placebo were administered as 8-mg doses twice daily for 12 months

Fig. 3

Comparison of absolute leukocyte counts (Cells/μL from Trucount assay) between TA-65 and placebo treated patients at baseline, 6 months and 12 months. (A) Total lymphocytes. (B) T-lymphocytes. (C) CD4⁺ T-lymphocytes. (D) CD8⁺ T-lymphocytes. (E) B-lymphocytes. (F) Natural Killer (NK) cells. (G) Neutrophils. (H) Monocytes.(A)–(H): Patients on TA-65 are depicted with red squares (n = 45 at baseline, n = 37 at 6 m, n = 40 at 12 m) and placebo-treated patients with blue circles (n = 45 at baseline, n = 36 at 6 m, n = 42 at 12 m). All time points are shown as mean ± standard error of mean. We performed two different statistical tests: a) 6 month and 12 month time points in each treatment arm were compared against baseline value and p value placed next to related data point using linear regression model (* is p < 0.05, ** p < 0.01, and *** p < 0.004), b) p value for treatment effect TA-65 vs. placebo after 12 months is stated next to bracket of 12 month data points using a mixed-effect linear model assuming Gaussian distribution for the error term

Fig. 4

Comparison of absolute leukocyte populations (Cells/μL from Trucount assay) between TA-65 and placebo treated patients stratified to MI type at baseline and 12 months. (A) Total lymphocytes. (B) T-lymphocytes. (C) CD4⁺ T-lymphocytes. (D) CD8⁺ T-lymphocytes. (E) B-lymphocytes. (F) Natural Killer (NK) cells. (G) Neutrophils. (H) Monocytes. (A)–(H): Patients on TA-65 are depicted with red squares and placebo-treated patients with blue circles (left: STEMI n = 22 at baseline, n = 22 at 12 m, right: NSTEMI n = 21 at baseline, n = 20 at 12 m). All time points are shown as mean ± standard error of mean. P value for treatment effect TA-65 vs. placebo after 12 months is stated next to bracket using a mixed-effect linear model assuming Gaussian distribution for the error term. STEMI = ST-elevation myocardial infarction. NSTEMI = non-ST elevation myocardial infarction

Fig. 5

Comparison of mean hsCRP (mg/L) between TA-65 and placebo treated patients stratified to MI type at baseline, 6 months and 12 months. hsCRP is shown using a logarithmic scale. Patients on TA-65 are depicted with red squares and placebo-treated patients with blue circles. Left: STEMI patients (n = 20 at baseline, n = 17 at 6 m, n = 20 at 12 m), and to the right NSTEMI patients (n = 22 at baseline, n = 19 at 6 m, n = 20 at 12 m). All time points are shown as mean ± standard error of mean. We performed two different statistical tests: 6 month and 12 month time points in each treatment arm were compared against baseline value and p value placed next to related data point using linear regression model (* is p < 0.05, ** p < 0.01, and *** p < 0.004), b) p value for treatment effect TA-65 vs. placebo after 12 months is stated next to bracket of 12 month data points using a mixed-effect linear model assuming Gaussian distribution for the error term. CRP = C-reactive protein, STEMI = ST-elevation myocardial infarction. NSTEMI = non-ST elevation myocardial infarction