Hyperglycemia and Mitochondrial Function in The Endothelium of Humans

Subjects will be recruited according to our inclusion/exclusion criteria. The investigators
employ a multifaceted approach to recruitment, including flyers, community newspaper ads,
internet ad postings, and direct recruitment from the Internal Medicine Clinics of Froedtert
Memorial Lutheran Hospital/Medical College of Wisconsin which saw approximately 50,000 unique
outpatient visits over last year. The electronic health record is leveraged to identify
potential subjects by HIPAA guidelines and Medical College of Wisconsin policies. Potential
subjects will undergo phenotyping that includes a detailed medical history, anthropomorphic
measurements, blood pressure and heart rate measurements, and a blood draw for measurements
that include fasting lipids, glucose, and glycosylated hemoglobin, creatinine, and liver
function tests. Healthy, non-DM subjects who pass the screening as per the
inclusion/exclusion criteria in Table 2 will be enrolled in the study protocol.

Following an overnight fast (12 hours), subjects will come in the morning to our Adult
Translational Research Unit (A-TRU) which is part of the Clinical Translational Research
Initiative of Southeast Wisconsin (8UL1TR000055). An antecubital intravenous line will be
placed to facilitate blood glucose sampling during the hyperglycemic challenge. An
antecubital intravenous catheter will be placed to facilitate obtaining endothelial cells
from the vein by J-wire biopsy for of mitochondrial testing. The principal investigator has
published experience with the J-wire endothelial cell biopsy technique, and the technique has
been extensively validated technique. An initial venous glucose sample will be taken from the
antecubital vein and an initial J-wire biopsy of the radial artery endothelium will be
performed through the radial arterial line. Subjects will then be asked to drink a
standardized 75 g glucose drink created by the A-TRU nutritionist- a standard oral glucose
challenge as used clinically. Blood glucose samples will be taken hourly after that until 4
hours post drink ingestion. At one and 4 hours post-ingestion, J-wire endothelial biopsies of
the radial artery will be repeated. Four separate J wires will be passed into the radial
artery for each measurement time point (0,1, and 4 hours).

In non-diabetic subjects, the 75 g oral challenge induces a peak increase in systemic glucose
at 1-hour post-administration at which time endothelial dysfunction is concomitantly
detectable. Endothelial cells will be obtained via J-wire capture technique. A portion of the
endothelial cells isolated from the J-wires will be used to measure mitochondrial network
complexity prior hyperglycemic challenge, 1-hour post challenge, and 4 hours post challenge.
The investigators will visualize the mitochondrial networks in these cells using our
previously reported and validated immunofluorescence method using cytochrome c antibodies to
tag the mitochondria. Network fragmentation (high number=greater fragmentation and fission)
will be quantified by network fragmentation count calculated with ImageJ (NIH, Bethesda)
using a validated protocol.

Inclusion Criteria:

1. Adult age 21 to 70

2. No evidence of metabolic syndrome or diabetes, hypertension (BP≥140/90), or high
cholesterol (LDL≥160) at the time of screening.

Exclusion Criteria:

1. History of stroke, peripheral arterial disease, or coronary artery disease (as defined
by the presence of at least one coronary stenosis ≥ 40% on angiography or by confirmed
history of myocardial infarction by standard criteria).

2. History of bleeding disorders.

3. Evidence of other evident major illness including chronic renal insufficiency (plasma
creatinine > 1.4 for women or 1.5 for men), liver disease (liver enzymes greater than
2.5 x normal), and cancer

4. currently undergoing therapy or had therapy for cancer within 1 year of enrollment.

5. Pregnancy as determined by urinary human chorionic gonadotropin beta test

6. Thienopyridine, anti-thrombin/Xa, or warfarin therapy at time of screening

7. On medication for cholesterol or blood pressure