Minimally invasive versus open Roux-en-Y gastric bypass: effect on immune effector cells.
BACKGROUND
Minimally invasive surgery (MIS) has several potential benefits compared with the open approach, including potentially less perioperative immunosuppression. Data characterizing the differential stress responses have been limited to serum cytokine analyses and animal studies. We hypothesized that the open approach to Roux-en-Y gastric bypass (RYGB) has a more deleterious, negative, quantifiable effect on the peripheral blood mononuclear cells than does the MIS approach.


METHODS
Patients undergoing open and MIS RYGB for morbid obesity had blood samples collected preoperatively and postoperatively on days 1 and 2 and at the first follow-up visit. The peripheral blood mononuclear cells were isolated and analyzed for phenotype using flow cytometry, natural killer cell cytotoxicity using 51-chromium release assay, and gene expression using Affymetrix U133 Plus 2.0 microarray.


RESULTS
Patient age and body mass index were similar between the 2 groups. Postoperatively, differences within the open group were seen for CD3+/CD16- (T lymphocytes), CD3-/CD16+ (natural killer cells), CD3+/CD4+ (T-helper lymphocytes), and CD4/CD8 subsets (P<.05). No differences were seen within the open group CD3+/CD8+ (cytotoxic T lymphocytes) or within the MIS subsets. Between the 2 approaches, no phenotypic differences were found, except for the postoperative day 1 CD3+/CD16- (P<.05). Within each group, significant decreases were found in cytotoxicity on days 1 and 2 compared with preoperatively (P<.05). The cytotoxicity seen after MIS had returned to the preoperative levels at the first follow-up visit, but the cytotoxicity after open RYGB had not (P<.05). Between the 2 groups, the open group had greater cytotoxic decreases than did the MIS group at postoperative days 1 and 2 (P<.05). Microarray analysis of the preoperative (n=20) and day 2 (n=20) specimens identified a 20-gene signature that correlated with the surgical approach.


CONCLUSIONS
Open RYGB surgery causes greater inhibition of innate immunity than does MIS. This inhibition was not accounted for by phenotypic changes. Gene expression changes from surgical stress might represent the molecular basis of this differential immune response.
Whitson
Bryan A
BA
Department of Surgery, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA. bwhit@umn.edu
D'Cunha
Jonathan
J
Hoang
Chuong D
CD
Wu
Baolin
B
Ikramuddin
Sayeed
S
Buchwald
Henry
H
Panoskaltsis-Mortari
Angela
A
Kratzke
Robert A
RA
Miller
Jeffrey S
JS
Maddaus
Michael A
MA
D000328:Adult; D017252:CD3 Complex / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003602:Cytotoxicity, Immunologic / Q000235:genetics / Q000276:immunology*; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000379:methods*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006801:Humans; D007111:Immunity, Cellular / Q000235:genetics / Q000276:immunology; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D009767:Obesity, Morbid / Q000097:blood / Q000276:immunology* / Q000601:surgery; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011184:Postoperative Period; D011446:Prospective Studies; D012313:RNA / Q000235:genetics; D017452:Receptors, IgG / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
D017252:CD3 Complex; D017452:Receptors, IgG; D012313:RNA