GLP-2 as an indicator and modulator of acute inflammation improves cardiac function and survival in sepsis

Purpose

GLP-1 and GLP-2 (glucagon-like peptide-1/2) are gut hormones secreted in response to food. While GLP-1 controls glucose metabolism, GLP-2 is a local gut growth factor regulating intestinal nutrient absorption. GLP-2 has been found to be upregulated in patients with colitis. We hypothesize that beyond its local intestinal function GLP-2 might be involved in systemic immune responses.

Methods and results

To analyze whether GLP-2 secretion is modulated by the immune system, we measured circulating GLP-2 levels in 2 clinical cohorts. In the first cohort (n=34) GLP-2 levels increased over time following cardiac surgery as an inflammatory stimulus. In the second cohort 223 patients with sepsis had a 3.9 fold increase of GLP-2 plasma levels vs. 53 healthy controls (3.0 ng/mL vs. 11.4 ng/mL; p<0.001). High GLP-2 levels were associated with markers of inflammation (IL-6, PCT, CRP), septic cardiomyopathy (NT-proBNP) and independently predicted mortality in humans with sepsis. Induction of sepsis in mice by endotoxin or cecal ligation puncture strongly increased GLP-2 levels independent from food intake. By injecting various proinflammatory cytokines and inducing sepsis in IL1R−/− and IL6−/− mice we identified that inflammation upregulates GLP-2 secretion through IL-6. To identify the source of GLP-2 secretion under inflammation, we induced sepsis in Gcg−/− mice lacking endogenous GLP-2 production with a tissue-specific reactivation of Gcg in gut L-cells (GcgRAΔvilCre) or pancretic alpha cells (GcgRAΔPDX1-Cre). We observed sepsis-induced GLP-2 secretion to be derived from the pancreas and not from the gut. Additional in-vitro and ex-vivo approaches revealed that IL-6 directly activates GLP-2 secretion from pancreatic alpha cells. Gcg−/− mice lacking GLP-2 production and Glp2r−/− mice show aggravated sepsis indicating that endogenous upregulation of GLP-2 is protective. Finally, we analyzed whether inflammatory upregulation of GLP-2 has immunomodulatory relevance. We administered GLP-2 or saline as control per central jugular vein catheter mice who underwent CLP. GLP-2 treatment improved LV-contractility (dp/dtmax) in septic cardiomyopathy (control 7361 vs. GLP-2 9500 mmHg/s; p<0.01), inhibited sepsis-induced hypotension and reduced mortality (p=0.018). Mechanistically GLP-2 reduced myeloid immune cell infiltration into heart and liver tissue and decreased proinflammatory cytokine levels in various organs and the blood (TNF-α, IL-6 and IL-1β). After broad GLP-2 receptor profiling we found maximum mRNA expression in gut tissues with no expression on immune cells. By further mechanistic studies we found GLP-2 to protect against sepsis-induced gut barrier dysfunction.

Conclusions

Here we identified a counter-regulatory control system in which IL-6 derived upregulation of GLP-2 secretion limits excessive innate immune responses and protects against sepsis. These findings might open new avenues for the treatment of patients with inflammatory diseases.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): European Foundation for the Study of Diabetes, European Research Area Network on Cardiovascular Diseases (ERA-CVD and BMBF), Deutsche Forschungsgemeinschaft (DFG)

P1757GLP-1 levels predict cardiovascular risk in patients with acute myocardial infarction

Background

Glucagon-like peptide 1 (GLP-1) is a gut incretin hormone, which induces post-prandial glucose-dependent insulin secretion. GLP-1 receptor agonists improve cardiovascular outcomes in patients with diabetes at high cardiovascular risk. We recently found GLP-1 levels to be increased in patients with acute myocardial infarction.

Purpose

The aim of this study was to assess the predictive capacity of GLP-1 for cardiovascular outcome in patients with myocardial infarction.

Methods

Total GLP-1 levels, NT-proBNP concentrations and the Global Registry of Acute Coronary Events (GRACE) score were assessed at time of admission in 918 patients with myocardial infarction presenting with acute chest pain. Among these 597 patients presented with NSTEMI and 321 with STEMI. The primary composite outcome of the study was the first occurrence of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke with a median follow-up of 311 days.

Results

Kaplan-Meier survival plots (separated by tertiles with cut-off values 35.44 and 53.45) and univariate cox regression analyses found GLP-1 values to be associated with adverse outcome (combined endpoint and all-cause mortality) (logarithmized GLP-1 values HR: 5.459; p<0.0001). Further adjustment for age, sex, previous cardiovascular disease, diabetes, hypertension, hypercholesterinemia, kreatinin, CRP, troponin T and NT-proBNP levels did not affect the association of GLP-1 with adverse outcomes (p=0.0341). Receiver operating characteristic curve analyses illustrated that GLP-1 is a strong indicator for early events (area under the curve of the combined endpoint at 7 days: 0.79; 14 days: 0.81; 30 days: 0.80 and 183 days: 0.64), which proved to be superior to Troponin T, serum creatinin, NT-proBNP and CRP within the first 100 days. Adjustment of the GRACE risk estimate by GLP-1 increased the area under the receiver-operating characteristic curve (AUC) after 1 month from 0.86 to 0.89 in NSTEMI patients. Addition of GLP-1 to a model containing GRACE and NT-proBNP led to a further improvement in model performance (increase in AUC from 0.88 for GRACE + NT-proBNP to 0.90 for GRACE + NT-proBNP + GLP-1).

Conclusion

GLP-1 is a new biomarker of cardiovascular risk and adverse outcomes in patients with acute myocardial infarction and improves the predictive value of the GRACE score in patients with NSTEMI.