Anti-inflammatory protection of early vs delayed sodium-glucose cotransporter-2 inhibitor therapy on monocyte-derived macrophages from patients with type2 diabetes with acute myocardial infarction

Background Systemic inflammation is a hallmark of acute myocardial infarction (AMI) with residual inflammatory risk a key player in reoccurring cardiovascular events. Use of sodium-glucose cotransporter-2 inhibitors (SGLT2i) in patients with type-2 diabetes mellitus (T2DM) and AMI improves cardiovascular outcomes, yet the mechanism of action is unknown. Purpose We posit that Empagliflozin (EMPA) provides anti-inflammatory protection via suppression of the nod-like receptor protein-3 (NLRP3) inflammasome in monocyte-derived macrophages (MDMs), and that this protection is greater in early (Arm A: prescribed EMPA during AMI admission at T0, T30, T90 and T180days) versus delayed therapy (Arm B: EMPA prescribed 90days post-discharge with sampling at T90, T120 and T180days), plus appropriate controls (T0-T90). Methods Patients presenting with T2DM-AMI, eligible but not already taking an SGLT2i were recruited and randomised to Arm A (n=28) or B (n=27). Blood CD14+ monocytes were isolated and differentiated into MDMs. An inflammasome assay measured Caspase-1 activity (direct inflammasome activation) in lipopolysaccharide (0.1ug/mL) + ATP (2mM) stimulated MDMs. Quantitative RT-PCR and Lumit immunoassays measured IL1β, IL6, and TNFα gene expression/secretion. Results IL1β expression (NLRP3 priming) decreased in MDMs isolated from patients in Arm A given EMPA at T0, at all subsequent timepoints from 2.13±0.53 (T0) to 0.64±0.37 (T30; P<0.05), 0.89±0.20 (T90; P<0.05) and 0.66±0.14 (T180; P<0.05). No change in IL1β expression was observed in Arm B both without EMPA (T0-90) or when EMPA was delayed (T90-180). Caspase-1 activity decreased with EMPA in Arm A from 8677±1550 to 4751±591.7 (T0-90; P<0.05) and 3772±450.2 RLu; (T0-180; P<0.01) whilst no significant reduction in caspase-1 activity was recorded in MDMs from Arm B. Although early therapy failed to alter TNFα levels (T0-T180), EMPA prevented the early increase in TNFα gene expression in Arm B MDMs (No EMPA) at T0-T30 (0.537±0.104 to 1.148±0.236 P<0.01). EMPA also reduced TNFα release when taken immediately prior to discharge (from 5240±1201 to 2409±363.6pg/mL; P<0.05; T0-90) compared to Arm B patients without EMPA (T0-90;) or with delayed therapy (T90-180). Lastly, early initiation of EMPA reduced IL6 secretion from 2248± 609.5 (T0) to 883.3±180.4 (T30; P<0.05) and 735.2±0.5pg/mL (T180; P<0.05). In the absence of EMPA, IL6 release increased from 571.9±96.57 (T0) to 1279±243.3 (T30; P<0.05) and 1617±396pg/mL (T90; P<0.05). Levels were restored with EMPA (from 1617±396 to 661.9±82.95pg/mL; P<0.05; T90-180). Conclusion UK NICE guidelines do not stipulate if SGLT2i’s should be prescribed during admission with AMI prior to discharge, or 90days post-discharge. This study suggests that anti-inflammatory protection of EMPA on MDMs from people with T2DM who have had an AMI is greatest following early therapy, timing of which may reduce residual inflammatory risk and improve clinical outcomes.