The effect of lactation in the post-partum arthritis of MRL-lpr/fasmice

Arthritis and prolactin: a phylogenetic viewpoint

Arthritic disorders are family of diseases that have existed since vertebrate life began. Their etiology is multifactorial with genetic, environmental, and gender factors driving chronic joint inflammation. Prolactin is a sexually dimorphic hormone in mammals that can act to both promote and ameliorate rheumatic diseases. It is found in all vertebrate groups where it exerts a wide diversity of actions. This review briefly addresses the presence and features of arthritic diseases in vertebrates, the effects of PRL on joint tissues and immune cells, and whether PRL actions could have contributed to the ubiquity of arthritis in nature. This comparative approach highlights the value of PRL as a biologically conserved factor influencing the development and progression of arthritis.

A population-based study of breastfeeding in inflammatory bowel disease: initiation, duration, and effect on disease in the postpartum period

OBJECTIVES

We aimed to assess breastfeeding practices and the impact of breastfeeding on disease flare during the postpartum year in inflammatory bowel disease (IBD).

METHODS

Women of childbearing age from 1985 to 2005 were identified from the University of Manitoba IBD Research Registry. Questionnaires were completed regarding pregnancy and the postpartum period. Data for initiation and duration of breastfeeding were compared with population-based regional data.

RESULTS

Of 204 eligible women, 132 (64.7%) responded to the survey, yielding information on 156 births. Breastfeeding was initiated in 83.3% of women with IBD (n=132), 81.9% of Crohn's disease patients (CD, n=90), and 84.2% of ulcerative colitis patients (UC, n=39) vs. 77.1 % in the general population (P>0.05 for all). Of women with IBD, 56.1% breastfed for >24 weeks vs. 44.4% of controls (P=0.02). The rate of disease flare in the postpartum year was 26% for those who breastfed vs. 29.4% in those who did not (P=0.76) in CD and 29.2% vs. 44.4% (P=0.44) in UC. The odds ratio of disease flare postpartum for those who breastfed vs. those who did not was 0.58 (95% CI: 0.24-1.43), 0.84 (0.19-9.87), and 0.51 (0.12-2.2) for IBD total, CD, and UC, respectively. Risk of disease flare was not related to age at pregnancy, duration of disease, or socioeconomic status.

CONCLUSIONS

Women with IBD are as likely as the general population to breastfeed their infants. Breastfeeding is not associated with an increased risk of disease flare and may even provide a protective effect against disease flare in the postpartum year.

Hormonal regulation of B-cell function and systemic lupus erythematosus

The prevalence of systemic lupus erythematosus (SLE) is far higher in females than in males and numerous investigations to understand this gender bias have been performed, which propose as casual actors genetic predispositions and sex hormones effects. We will describe in this review how the sex hormones estrogen and prolactin influence B cell maturation and selection, permitting B cells to mature to immunocompetence in a mouse model of lupus. Finally, we will discuss the relevance and implications of these results for human disease.

Skin disease is prevented but nephritis is accelerated by multiple pregnancies in autoimmune MRL/LPR mice

The role of pregnancy in the progression of systemic lupus erythematosus (SLE) is still poorly understood. We analysed the effect of repeated pregnancies in MRL/lpr mice, a murine model of SLE. Seven-week old female mice were used: multiparous mice underwent three consecutive pregnancies (M); age-matched virgin mice served as controls (V). Animals were harvested at 20 weeks of age. Skin lesions were characterized by hair loss and scabs in the dorsum of the neck. Virgin skins showed thickened dermis, fibrosis and mononuclear cell infiltrates, which were practically absent in M. This was accompanied by higher IFN-gamma and lower IL-10 mRNA expression levels in V compared to M skin. Plasma IFN-gamma protein levels were also upregulated in V versus M. However, survival and kidney function were dramatically reduced and accompanied by hypertension after multiple pregnancies. Kidney histology also showed markedly increased renal lesions in M. In contrast to plasma and skin levels, both IL-10 and IFN-gamma mRNA were lower in the kidneys of V versus M mice. Concluding our findings, the pathomechanisms of lupus kidney and skin disease may be regulated differently at the organ level during pregnancy. Both IFN-gamma and IL-10 may be important regulatory cytokines at the local level.

Sex hormones and SLE: influencing the fate of autoreactive B cells

The prevalence of systemic lupus erythematosus (SLE) is far higher in females than in males and numerous investigations to understand this gender bias have been conducted. While it is plausible that some sex-linked genes may contribute to the genetic predisposition for the disease, other likely culprits are the sex hormones estrogen and prolactin. In this chapter we review studies that have addressed the influence of sex hormones in SLE activity and discuss the recent data established in a BALB/c mouse transgenic for the heavy chain of an anti-DNA antibody. These mice are prone to develop lupus following exposure to exogenous sex hormones. We describe how estrogen and prolactin influence B cell maturation and selection, permitting B cells to mature to immunocompetence. Finally, we discuss the relevance and implications of these data for human disease.

The role of breastfeeding in postpartum disease activity in women with inflammatory bowel disease

BACKGROUND

Women with inflammatory bowel disease (IBD) have an increased risk of experiencing a flare in the postpartum period. Work in other autoimmune disorders has found that breastfeeding may be associated with an increased risk for developing postpartum disease relapse.

AIM

To assess the association between breastfeeding behavior and postpartum disease activity.

METHODS

Women with IBD followed at a tertiary care center with a history of childbirth within the past 5 yr were recruited. Medical records were reviewed for disease type, disease activity during and after pregnancy, medication use, smoking, and breastfeeding behavior. The exposure of interest was breastfeeding prior to the onset of disease activity following a successful asymptomatic pregnancy.

RESULTS

One hundred and twenty-two consecutive women who fit eligibility criteria were studied. Overall, only 44% (54/122) of the women had breastfed their infant. Reasons included physician recommendation, fear of medication interactions, and personal choice. Forty-three percent (23/54) of those who breastfed experienced a postpartum flare of their disease. The unadjusted odds ratio for disease activity with a history of breastfeeding was 2.2 (95% CI 1.2-3.9, p= 0.004). When stratified by disease type, the OR for ulcerative colitis was 0.89 (0.29-2.7, p > 0.05) and Crohn's disease 3.8 (1.9-7.4, p < 0.05). When adjusted for medication cessation, the OR became nonsignificant.

CONCLUSIONS

A significant number of women with IBD do not breastfeed their children. Any relationship between breastfeeding and disease activity may be more a consequence of discontinuation of IBD therapies.

Prolactin as a modulator of B cell function: implications for SLE

Prolactin is not only a lactigenic hormone but also an immunomodulator involved in lymphocyte survival, activation and proliferation. There is increasing data implicating prolactin in autoimmunity, and specifically in SLE. Increased serum prolactin levels have been reported in lupus patients of both genders, and have been associated with accelerated disease expression and early mortality in lupus-prone mice. Furthermore, suppression of prolactin secretion with bromocriptine provides beneficial effects in murine lupus, and perhaps in some SLE patients as well. Treatment with prolactin that causes mild to moderate hyperprolactinemia, similar to that present in SLE patients, breaks tolerance and induces a lupus-like illness in non-spontaneously autoimmune mice with a susceptible genetic background. These immuno stimulatory effects of prolactin are mediated by a decrease in negative selection and the maturation of autoreactive B cells to the follicular subset. Consistent with the fact that follicular B cells are T cell dependent, CD4+ T cells are necessary for the prolactin-mediated break down of B cell tolerance. In mice, the effects of prolactin on the immune system are genetically determined, suggesting that only a subset of SLE patients are likely to have a prolactin-responsive disease. The manipulation of serum prolactin or, even more specifically, follicular B cells that are susceptible to the immuno stimulatory effects of prolactin, may provide novel therapeutic options for those SLE patients with a prolactin-modulated disease.

Prolactin in murine systemic lupus erythematosus

Murine systemic lupus erythematosus (SLE) manifests several autoimmune perturbations that resemble human SLE, including cytokine aberrations, lymphoproliferation, hypergammaglobulinemia, autoantibody formation, and immune complex glomerulonephritis. In multiple studies, elevated serum prolactin concentrations (hyperprolactinemia) stimulated appearance or progression of murine lupus. Autoimmune disease acceleration by prolactin appears to be accentuated by estrogen stimulation of prolactin secretion and independent of immunosuppressive effects of androgens such as testosterone. Conversely, suppression of serum prolactin concentrations by bromocriptine inhibits development of murine SLE. These data clearly support the concept that prolactin is immunostimulatory in autoimmune disease and that the therapeutic goal of lowering serum prolactin concentrations may be beneficial to patients. Further utilization of murine SLE models will facilitate dissection of the actions and interactions of prolactin with estrogen, progesterone and testosterone and lead to a better understanding of hormonal immunomodulation and therapy of autoimmune disease.