The concentration of a protein known to be involved in insulin resistance was significantly higher in serum of both lean and obese psoriasis patients, based on data from 80 adults.
The protein – known as wingless-type MMTV integration site Family, Member 5a (wnt5a) – also is upregulated in psoriatic skin lesions, noted Dr. Sascha Gerdes of the University Medical Center Schleswig-Holstein, Kiel, Germany, and colleagues.
"We investigated whether wnt5a and its counterpart, secreted frizzled-related protein 5, are altered in the circulation of lean and obese patients with psoriasis compared with lean and obese healthy volunteers by measuring serum concentrations of both proteins," they wrote (Experimental Dermatology 2014;23:439-40).
The mean serum concentration of wnt5a was significantly higher in 20 lean psoriasis patients, compared with 20 lean healthy controls (0.096 ng/mL vs. 0.020 ng/mL, respectively, P less than or equal to .01). The difference was even more pronounced in the serum samples from 20 obese psoriasis patients, compared with 20 obese healthy controls (0.177 ng/mL vs. 0.011 ng/mL, respectively, P less than or equal to .001).
There was no significant difference in the mean serum concentration of secreted frizzled-related protein 5 (sFRP5) in lean psoriasis patients, compared with lean controls. However, obese psoriasis patients had significantly higher concentrations of sFRP5, compared with obese controls (14.358 ng/mL vs. 6.389 ng/mL, respectively).
A second set of experiments on the serum samples of 50 psoriasis patients ranging from lean to obese showed that wnt5a levels increased as body mass index increased and was statistically significant in patients with a body mass index between 35 and less than 40 kg/m2, compared with lean patients who had a BMI between 20 and less than 25 kg/m2 (0.337 ng/mL vs. 0.125 ng/mL, respectively).
"We hypothesize that the expression of wnt5a in psoriatic lesions subsequently leads to an increase in wnt5a in the circulation, which could partly explain why metabolic comorbidity such as insulin resistance and diabetes mellitus type 2 develops in psoriasis patients with and without obesity," the researchers noted.
Although the findings suggest a role for wnt5a in the interaction of psoriasis and metabolic comorbidities, additional studies are needed to determine how psoriasis treatment and/or weight management might impact both wnt5a and sFRP5 in psoriasis patients, they added.
The researchers had no financial conflicts to disclose.