Autoimmunity: limited progress for the patient, despite decades of research

Longevity of SLE-prone mice increased by dietary 2-mercaptoethanol via a mechanism imprinted within the first 28 days of life

In the preceding report, moderately lived-mice fed dietary 2-mercaptoethanol (2-Me) had their life extended, whereas long-lived mice were found to have the quality of life improved, but not extended, and did not develop high fat-diet obesity. In the present report, alteration of longevity of mice prone to develop spontaneous, systemic lupus erythematosus (SLE) by dietary 2-Me was determined. NZB, NZW, (NZW x NZB) F₁-hybrid, BXSB/MpJ, BXSB-Yaa+/J, MRL/MpJ and MRL/MpJ-Faslpr mice received drinking water, without or with 2-Me at concentrations of 10⁻³ or 10⁻² M. Therapeutic benefit was assessed by changes in longevity. The median survival of MRL/MpJ males was increased from 443 to 615 days and those of (NZW x NZB) F₁ and NZB males and females were increased approximately 2-fold. The most unexpected finding was that longevity of F₁ males was significantly extended irrespective of whether dietary exposure to 2-Me was initiated at 28 days of age, at 50 days of age, or initiated during gestation (and then terminated at weaning--28 days of age). Survival of F₁-hybrids in which treatment was initiated in utero or at 28 days of age was not significantly different, whereas if initiation was delayed until 50 days of age, survival was >200 days shorter. Survival of male MRL/MpJ-Fas lpr and BXSB/MpJ (Yaa-), two strains with genetically controlled accelerated SLE, was not altered by 2-Me when started at 50 days. Various alternatives are discussed regarding potential long-lasting mechanisms imprinted early in life. Even though present day treatments of rodent SLE are generally aimed at controlling specific immunological events, with or without survival benefits, or are procedures presently unsuitable for therapeutic use in humans, the findings presented herein seem worthy of clinical evaluation.