Dietary Cholesterol and Adipose Tissue Inflammation

Hypothesis: increasing dietary cholesterol in humans will increase visceral, but not subcutaneous adipocyte size, free cholesterol content, and inflammatory gene expression.

Visceral and abdominal subcutaneous adipose tissue biopsies will be obtained from non-obese subjects undergoing elective abdominal surgery at Wake Forest Baptist Medical Center after 3 weeks of zero (control) or 1g dietary cholesterol supplementation. Blood samples will also be taken before and after 3 weeks of dietary supplementation (0 vs. 1g dietary cholesterol) to measure plasma lipids levels, and ex vivo monocyte chemotaxis. Blood will also be used to isolate CD14+ monocytes for RNA extraction and storage for future transcriptome studies. Measurements of adipocyte size, free cholesterol content, and inflammatory gene and protein expression in the adipose tissue biopsies to test the hypothesis. Adipocytes and the stromal vascular fraction will be isolated and evaluated for CD14+ macrophages for RNA extraction and storage for future transcriptome analysis.

A Wake Forest School of Medicine Clinical Research Unit-based pilot study will be conducted in which subjects scheduled to undergo elective intra-abdominal surgery at Wake Forest Baptist Medical Center (i.e., cholecystectomy, Nissen fundoplication, hernia repair, etc.) will be recruited. Subjects will be randomly and blindly assigned to receive daily treats (cookie, brownie, or muffin) containing either no added cholesterol (control) or 1g of cholesterol/day (\~0.4 mg/Kcal cholesterol) for 3 weeks prior to surgery. Three weeks for the length of cholesterol supplementation has been chosen because this is within the duration of human egg-consumption studies in which significant elevations in plasma LDL concentrations occurred. A blood sample will be taken from each participant at baseline before starting the supplementation period and after 3 weeks of 0 or 1g/day cholesterol supplementation, at the time of scheduled surgery. The blood samples will be used for measurement of lipid profile, ex vivo monocyte chemotaxis, and for monocyte RNA isolation. During surgery, abdominal wall subcutaneous adipose tissue and mesenteric (visceral) adipose tissue samples will be obtained. Aliquots of adipose tissue will be fixed overnight for histology and measurement of adipocyte size distribution and CD68 immunostaining, flash frozen and stored for cholesterol quantification by gas liquid chromatography, extracted to isolate RNA and protein for quantitative real time PCR and immunoblotting of inflammatory gene and protein expression, and collagenase digested to isolate adipocytes and stromal vascular cell fraction macrophages which will be used to extract and store RNA for future transcriptome analyses.

Eligibility Criteria:
Inclusion Criteria:

* Age:18 to 70 years old
* Operated on by one of the study team surgeons at Wake Forest Baptist Medical Center.

Exclusion Criteria:

* History of liver disease (e.g., autoimmune hepatitis, Wilson's disease, hemochromatosis, 1 anti-trypsin deficiency), as determined by chart review
* Childs A, B, or C cirrhosis, as determined by chart review
* Present diagnosis/treatment of malignancy other than non-melanoma skin cancer
* Baseline INR \> 1.8, as determined by chart review or need for continuous anticoagulation with warfarin or heparin
* Platelets \<50,000 as determined by chart review
* Active immunomodulation therapy for chronic inflammatory diseases, including but not limited to rheumatoid arthritis, psoriasis, SLE, sarcoidosis, or inflammatory bowel disease
* Diabetes mellitus requiring treatment with oral agents or insulin
* Taking Questran, Colestid, or Zetia
* BMI over 30