Vitamin c may help stiff red blood cells in diabetes

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

* INCLUSION CRITERIA: Study Initiation * Male or female 18-65 years old, able to give informed consent. * Diabetes type 2 HgA1C \<= 12% on insulin and/or oral hypoglycemic agents or nondiabetic without any prior history or diagnosis of diabetes. * In general good health with no other significant illness. * Mild concomitant disease such as mild hypothyroidism (TSH \<10) is acceptable. * Blood pressure with or without medication \<160/90 mmHg with no known significant target organ damage (end organ damage includes the following: proliferative retinopathy, serum creatinine \>1.5 or EGFR \< 55 mL/min, symptomatic ischemic heart disease, severe congestive heart failure, advanced peripheral vascular disease. * Willingness to use effective contraceptive methods such as barrier method for the duration of study (female subjects). 8-week follow-up Above criteria with addition of RBC vitamin C concentration \>30 uM prior to inpatient studies. EXCLUSION CRITERIA: Entire duration of study * Diabetic type 1 subjects will be excluded due to the possibility of ketosis and hemodynamic instability with lack of insulin. * Any subjective or objective evidence of microangiopathy such as history of claudication, symptomatic peripheral vascular disease, symptomatic coronary artery disease, stroke, retinopathy, nephropathy (serum creatinine \>1.5 or EGFR \< 55 mL/min). * Diabetic subjects with retinopathy to avoid accelerated retinopathy with hyperglycemia. * Concomitant disease such as severe heart failure, severe liver disease (transaminases \> 3 times normal), or severe systemic disease of any sort. * Pregnancy, breastfeeding. * History of diabetic ketoacidosis or hyperosmolar coma. * Subjects with clear evidence of non-compliance with protocol/study instructions. * Subjects who are unwilling or lack capacity to provide informed consent.