High levels of CRP in morbid obesity: the central role of adipose tissue and lessons for clinical practice before and after bariatric surgery.
BACKGROUND
Obesity, characterized by low-grade inflammation both in blood and white adipose tissue (WAT) is associated with increased C-reactive protein (CRP), a well-known acute phase protein. The aim of this study was to determine factors associated with high levels of CRP in obesity.


METHODS
In 674 obese patients candidates to bariatric surgery (mean body mass index [BMI]=47.4±7.4 kg/m²), we examined the relationships between CRP and a series of bioclinical markers and histologic features of subcutaneous and omental WAT (scWAT) and liver. We also compared the same parameters after separating patients with "high" inflammation (HI, CRP≥20 mg/L, n=52) and with "low" inflammation (LI, CRP<20 mg/L, n=622).


RESULTS
Mean CRP was 8.9±6.9 mg/L and positively correlated with fat mass (P<10(-4)). The HI group included predominantly women (92% versus 79%), of a younger age, with higher BMI (50.9±8.8 versus 47.1±7.2 kg/m2, P=.003), and fat mass (51.6 versus 48.8%, P<.001), higher prevalence of obstructive sleep apnea (OSA) (73% versus 57%, P=.02), and had increased number of HAM56+ immune cells in scWAT (20.8 versus 14.5%, P=.05). There was no difference in metabolic status, WAT fibrosis or liver histology findings between the groups. After 1 year of surgery-induced weight loss, 48 out of 52 patients with HI returned to CRP levels<20 mg/L.


CONCLUSIONS
Our results suggest that WAT inflammation is a major contributor to increased CRP in obesity. In obese patients presenting high CRP levels with no obvious explanation, age, gender, BMI, fat mass proportion, OSA, and WAT inflammation should be taken into account to decide to perform further additional medical investigations.
Institute of Cardiometabolism and Nutrition, ICAN, Pitié-Salpêtrière Hospital, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Nutrition Department, Heart and Metabolism Division, Paris, France.
Anne-Cécile
AC
Paepegaey
Institute of Cardiometabolism and Nutrition, ICAN, Pitié-Salpêtrière Hospital, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Bariatric and Digestive Surgery Department, Paris, France.
Laurent
L
Genser
Assistance Publique-Hôpitaux de Paris, Ambroise Paré Hospital, General, Digestive and Metabolic Surgery Department, Versailles Saint-Quentin University, Boulogne, France.
Jean-Luc
JL
Bouillot
Institute of Cardiometabolism and Nutrition, ICAN, Pitié-Salpêtrière Hospital, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Nutrition Department, Heart and Metabolism Division, Paris, France.
Jean-Michel
JM
Oppert
Institute of Cardiometabolism and Nutrition, ICAN, Pitié-Salpêtrière Hospital, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Nutrition Department, Heart and Metabolism Division, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S U1166 I, Nutriomic team, Paris, France; INSERM, UMR_S ICAN F U1166, Nutriomique team, Paris, France.
Karine
K
Clément
Institute of Cardiometabolism and Nutrition, ICAN, Pitié-Salpêtrière Hospital, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Nutrition Department, Heart and Metabolism Division, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S U1166 I, Nutriomic team, Paris, France; INSERM, UMR_S ICAN F U1166, Nutriomique team, Paris, France. Electronic address: christine.poitou-bernert@psl.aphp.fr.
Christine
C
Poitou
D052436:Adipose Tissue, White / Q000473:pathology / Q000503:physiopathology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D050110:Bariatric Surgery; D002097:C-Reactive Protein / Q000032:analysis*; D006801:Humans; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000503:physiopathology* / Q000601:surgery; D011184:Postoperative Period; D057234:Preoperative Period; D015431:Weight Loss; D055815:Young Adult
D002097:C-Reactive Protein
Adipose tissue; Bariatric surgery; C-reactive protein; Inflammation; Obesity; Weight loss