This study is currently recruiting participants.
Number
14-DK-0060
Sponsoring Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Recruitment Detail
Type: Participants currently recruited/enrolled Gender: Male & Female Min Age: 18 Years Max Age: 65 Years
Referral Letter Required
No
Population Exclusion(s)
Children
Keywords
Diabetes; Red Blood Cells; Vitamin C; Plasma Vitamin C Levels
Recruitment Keyword(s)
None
Condition(s)
Diabetes Type 2
Investigational Drug(s)
Investigational Device(s)
Intervention(s)
Dietary Supplement: Vitamin E Dietary Supplement: Vitamin C
Supporting Site
National Institute of Diabetes and Digestive and Kidney Diseases
During the two sampling periods, samples will be withdrawn via venous catheter for RBC deformability, vitamin C concentrations and other related research studies. Following completion of stage 1, subjects considered for participation in stage 2 will be provided a prescription for vitamin C 500mg twice daily. Given that vitamin C and vitamin E are related antioxidants, and that both vitamins appear to be associated with RBC rigidity, diabetic subjects may also be given a prescription for 400 international units (IU) of vitamin E (RRR alpha tocopherol) daily. Subjects will continue vitamin C and E supplementation for a minimum of 8 weeks depending on RBC vitamin C concentrations. To evaluate any effect of vitamin E supplementation, plasma and RBC vitamin E levels may be measured concurrently with vitamin C levels during various phases of stages 1 and 2. All subjects will be seen as outpatients at biweekly or monthly intervals with regular measurement of plasma and RBC vitamin C concentrations. Target RBC vitamin C concentration >30uM is required prior to stage 2 inpatient sampling studies. Vitamins C and E supplementation will be discontinued upon inpatient admission for stage 2. Risk of both vitamin supplements are minimal as both supplementation doses are safe. Outcomes are to measure RBC rigidity and vitamin concentrations before and after supplementation. After a minimum of 8 weeks (depending on RBC vitamin C levels), subjects will be hospitalized again, and sampling repeated as described. In this manner, each subject serves as his/her own control, and deformability of red blood cells can be determined in relation to glycemia and to vitamin C concentrations in RBCs and plasma.
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INCLUSION CRITERIA: Stage 1 -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). Stage 2 Above criteria with addition of RBC vitamin C concentration >30 uM prior to inpatient studies. EXCLUSION CRITERIA: Stage 1 and 2 -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.
Stage 1
-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).
Stage 2
Above criteria with addition of RBC vitamin C concentration >30 uM prior to inpatient studies.
EXCLUSION CRITERIA:
Stage 1 and 2
-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.
Principal Investigator
Referral Contact
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