Psoriasis is a common inflammatory
skin disease and
obesity constitutes a risk factor for the disease. Obese patients with
psoriasis are often more difficult to treat and are at increased risk for
dyslipidemia, diabetes,
hypertension and
cardiovascular disease. Case reports suggest that
gastric bypass surgery in patients with
psoriasis may result
in complete remission of the disease. A substantial
weight loss is achieved in the months following surgery, which is likely to reduce
psoriasis symptoms and risk of comorbidities. Interestingly, however, it has been described that improvement of
psoriasis is initiated immediately following surgery before any
weight loss could have happened. We hypothesize that the
glucose-lowering gut
incretin hormone glucagon-like peptide-1 (GLP-1) is responsible for this effect. The levels of
GLP-1 have been shown to increase up to 20 times after
gastric bypass surgery. This most likely contributes importantly to the acute remission of
type 2 diabetes, which is often induced by
gastric bypass operations. The
hormone is not hypersecreted after the purely restrictive bariatric procedure gastric banding and no case reports exist on improvement in
psoriasis following gastric banding. Intriguingly, recent studies describe that
GLP-1 may convey anti-inflammatory effects in addition to its effects on
glucose homeostasis. Also,
GLP-1 reduces appetite and gastrointestinal motility including gastric emptying, which reduces food intake and leads to
weight loss. Thus, both a direct anti-inflammatory effect of
GLP-1 as well as an indirect effect through
weight loss could contribute to improvement in
psoriasis. A potential involvement of
GLP-1 in the remission of
psoriasis observed after
bariatric surgery offers exciting possibilities for research and eventually perhaps new ways of anti-psoriatic treatment.