ACE2 and diabetes mellitus: The expression levels of angiotensin converting enzyme 2 (ACE2), acetylcholinesterase (AChE), interleukin-6 (IL-6), based on their involvement in both environmental responses and comorbid conditions, such as hypertension and type 2 diabetes mellitus, may substantially raise the respiratory syndrome coronavirus 2 (SARS-CoV-2) mortality [29].