Two groups of 25 subjects each will be studied: subjects with confirmed diabetic peripheral neuropathy (DPN) and age- and sex-matched healthy controls.

Inclusion Criteria:

1. Presence of diabetes mellitus diagnosed for more than 6 months as defined by the World Health Organization Classification.
2. Presence of confirmed DPN as defined below.
3. Age between 18-70 years.
4. Have no risk factors for other non-diabetic neuropathies (as determined by medical history, family history, history of medications, occupational history, history of exposure to toxins, physical and neurological examinations).
5. Willingness to provide informed consent and cooperate with the medical procedures for the study.

Inclusion Criteria for Healthy Controls:

1. Age-matched non-obese (BMI < 30) control subjects
2. Normal glucose tolerance
3. Normal blood pressure
4. Normal lipid profile
5. Free of any causes of neuropathy as described above.

Exclusion Criteria:

1. Nursing mothers or pregnant women (excluded by a positive pregnancy test).
2. Patients with a history of previous kidney, pancreas or cardiac transplantation.
3. Patients with a past history of neuropathy (independent of diabetes), or with a disease known to be associated with neuropathy (e.g. end stage renal disease, hepatitis C, systemic lupus erythematosus).
4. Participation in an experimental medication trial within 3 months of starting the study.
5. Subjects with implantable cardioverter defibrillators and other devices that would preclude MRI scanning.
6. Subjects who are unable or unwilling to comply with the experimental protocol.