Myocardial Insulin Resistance

Myocardial Insulin Resistance

Myocardial insulin resistance is said to occur in about 60% of patients with type 2 diabestes mellitus and is associated with higher cardiovascular risk compared to those with insulin sensitive myocardium [1]. It is  known that systemic insulin resistance is an independent risk factor for heart failure and cardiovascular death [2]. Myocardial insulin resistance occuring along with systemic insulin resistance is characterized by ineffecient energy metabolism and contributes to post ischemic heart failure. Myocardial insulin resistance can also be caused by myocardial hypertrophy, independent of systemic insulin resistance and is associated with mitochondrial damage. It is also a risk factor for heart failure [3].

Insulin resistance can prevent adaptive response of myocardium to injury. Normal myocardium responds to injury by altering substrate metabolism from lipids to glucose to increase energy efficiency. When this adaptive response is prevented by insulin resistance, it can enhance injury by lipotoxicity, sympathetic up regulation, inflammation, oxidative stress and fibrosis [4].

Myocardial insulin resistance has been documented by 18 Fluorodeoxy glucose positron emission tomography/computed tomography scan at baseline and after hyperinsulinemic-euglycemic clamp. Striking enhancement of ¹⁸FDG uptake uptake is seen in those who have myocardial insulin sensitivity while only a marginal increase is seen in those with myocardial insulin resistance [5].

References

1. Herance JR, Martín-Saladich Q, Velásquez MA, Hernandez C, Aparicio C, Ramirez-Serra C, Ferrer R, Giralt-Arnaiz M, González-Ballester MÁ, Pericàs JM, Castell-Conesa J, Aguadé-Bruix S, Simó R. Identification of Myocardial Insulin Resistance by Using Liver Tests: A Simple Approach for Clinical Practice. Int J Mol Sci. 2022 Aug 7;23(15):8783. doi: 10.3390/ijms23158783. PMID: 35955920; PMCID: PMC9369008.
2. Godsland IF, Lecamwasam K, Johnston DG. A systematic evaluation of the insulin resistance syndrome as an independent risk factor for cardiovascular disease mortality and derivation of a clinical index. Metabolism. 2011 Oct;60(10):1442-8. doi: 10.1016/j.metabol.2011.02.012. Epub 2011 Apr 2. PMID: 21459390.
3. Zheng L, Li B, Lin S, Chen L, Li H. Role and mechanism of cardiac insulin resistance in occurrence of heart failure caused by myocardial hypertrophy. Aging (Albany NY). 2019 Aug 28;11(16):6584-6590. doi: 10.18632/aging.102212. Epub 2019 Aug 28. PMID: 31461405; PMCID: PMC6738426.
4. Witteles RM, Fowler MB. Insulin-resistant cardiomyopathy clinical evidence, mechanisms, and treatment options. J Am Coll Cardiol. 2008 Jan 15;51(2):93-102. doi: 10.1016/j.jacc.2007.10.021. PMID: 18191731.
5. Herance JR, Simó R, Velasquez MA, Paun B, García-Leon D, Aparicio C, Marés R, Simó-Servat O, Castell-Conesa J, Hernández C, Aguadé-Bruix S. Phenotyping Type 2 Diabetes in Terms of Myocardial Insulin Resistance and Its Potential Cardiovascular Consequences: A New Strategy Based on ¹⁸F-FDG PET/CT. J Pers Med. 2022 Jan 2;12(1):30. doi: 10.3390/jpm12010030. PMID: 35055345; PMCID: PMC8778238.