C-reactive protein is a nonspecific marker of inflammation that is moderately elevated in obesity, metabolic, and type 2 diabetes.
It has been proposed as a surrogate marker of nonalcoholic steatohepatitis.
Dr Rodolphe Anty and colleagues from France evaluated its clinical usefulness in the diagnosis of nonalcoholic steatohepatitis in severely obese patients.
The patients were without or withmetabolic syndrome, diabetes, and nonalcoholic steatohepatitis.
The team of doctors characterized the potential roles of the liver and of the adipose tissue in C-reactive protein production.
The team studied 13 severely obese patients without nonalcoholic steatohepatitis and without metabolic syndrome, and 11 with with metabolic syndrome.
The doctors studied a further 7 with metabolic syndrome and diabetes and 15 with nonalcoholic steatohepatitis.
Of those with non-alcoholic steatohepatitis, 8 were without and 7 with metabolic syndrome.
For each patient, the team collected liver and adipose tissue biopsies during a bariatric surgery and were used to determine the C-reactive protein gene expression.
|C-reactive protein mRNA levels were positively correlated with those of interleukin-6|
|American Journal of Gastroenterology|
The role of interleukin-6 and lipopolysaccharide in C-reactive protein expression was also evaluated in subcutaneous adipose tissue obtained during cosmetic abdominoplasty.
The doctors elevated plasma C-reactive protein levels in severely obese patients independently of metabolic syndrome, diabetes, or nonalcoholic steatohepatitis.
The team found that C-reactive protein gene expression was not only increased in livers but also in adipose tissues of obese patients compared with controls subjects.
In human adipose tissue, C-reactive protein mRNA levels were positively correlated with those of interleukin-6.
The team observed that the C-reactive protein expression was enhanced in vitro by interleukin-6 and lipopolysaccharide.
Dr Anty's team concluded, “Plasma C-reactive protein levels are not predictive of the diagnosis of nonalcoholic steatohepatitis in severely obese patients.”
“The liver as well as the adipose tissue can produce C-reactive protein, a process which could be dependent on interleukin-6.”
“Therefore, both tissues might contribute to the elevated plasma C-reactive protein levels found in obesity.”
“In addition, the large amount of body fat may well produce an important part of the circulating C-reactive protein, further limiting its clinical usefulness in the evaluation of nonalcoholic steatohepatitis in severely obese patients.”