Treatment options in insulin resistance obesity-related acanthosis nigricans

OBJECTIVE

To evaluate the literature to determine which oral and topical medications are most effective in the treatment of insulin resistance obesity-related acanthosis nigricans (IRORAN).

DATA SOURCES

A MEDLINE literature search was conducted (1950-January 2008) using the search terms acanthosis nigricans (AN), metformin, rosiglitazone, octreotide, retinoic acid, acitretin, etretinate, and isotretinoin. The search was limited to articles on treatment of IRORAN in humans written in the English language. Articles were retrieved and all references were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Articles selected for inclusion were limited to AN related to obesity with no other underlying etiology. Clinical trials and case reports using monotherapy were included.

DATA SYNTHESIS

Metformin, rosiglitazone, octreotide, vitamin D analogs, and retinoic acid have been used in the treatment of IRORAN. In one randomized trial, metformin 500 mg 3 times daily was compared with rosiglitazone 4 mg once daily. Neither treatment demonstrated significant improvements in AN; however, rosiglitazone did significantly decrease serum insulin levels. In a second clinical trial and in several case reports, AN and hyperinsulinemia did show improvement with metformin treatment. After a 6-month period, octreotide improved IRORAN, body weight, and glucose/insulin response to a meal. The improvements persisted for 6 additional months after discontinuation of octreotide. Vitamin D analogs and retinoids produced inconsistent results in 5 separate case reports.

CONCLUSIONS

IRORAN is a growing problem, particularly in children and adolescents, secondary to the increase in the prevalence of obesity. Treatment of IRONAN should focus on reversal of the underlying hyperinsulinemia. Patients with IRORAN may benefit from a trial of metformin for improvement of lesions and underlying hyperinsulinemia.

Antitumor properties of diastereomeric and geometric analogs of vitamin D3

Analogs of 1,25-dihydroxyvitamin D3 with a reversed configuration at C-1 or C-24 and E or Z geometry of the double bond at C-22 in the side chain or at C-5 in the triene system were examined for their antiproliferative activity in vitro against a spectrum of various human cancer cell lines. The analogs coded PRI-2201 (calcipotriol), PRI-2202 and PRI-2205, such as calcitriol and tacalcitol (used as a referential agents), revealed antiproliferative activity against human HL-60, HL-60/MX2, MCF-7, T47D, SCC-25 and mouse WEHI-3 cancer cell lines. The toxicity studies in vivo showed that PRI-2202 and PRI-2205 are less toxic than referential agents. Even at total doses of 2.5-5.0 mg/kg distributed during 5 successive days, no changes in body weight were observed. Calcitriol and tacalcitol showed toxicity in the same protocol at 100 times lower doses. Calcipotriol was lethal to all mice after administration of a total dose of 5.0 mg/kg. The analog PRI-2205 appeared to be more active in mouse Levis lung cancer tumor growth inhibition than calcitriol, calcipotriol or PRI-2202. This analog did not reveal calcemic activity at doses which inhibit tumor growth in vivo nor at higher doses.