Metabolic bone disease is present at diagnosis in patients with inflammatory bowel disease

Colonic dendritic cells, intestinal inflammation, and T cell-mediated bone destruction are modulated by recombinant osteoprotegerin

Autoimmune associated bone disease and intestinal inflammation are closely linked with deregulation and hyperactivation of autoreactive CD4 T cells. How these T cells are activated and mediate disease is not clear. Here we show that in the Interleukin 2-deficient mouse model of autoimmunity spontaneous osteopenia and colitis are caused by increased production of the ligand for receptor activator of NFkappaB (RANKL). RANKL acting via its receptor, receptor activator of NFkappaB (RANK), increases bone turnover and promotes intestinal dendritic cell (DC) survival in vivo. Modulation of RANKL-RANK interactions with exogenous recombinant osteoprotegerin (Fc-OPG) reverses skeletal abnormalities and reduces colitis by decreasing colonic DC numbers. This study identifies a common causal link between bone disease and intestinal inflammation and establishes the importance of DC in mediating colonic inflammation in vivo.

Risk of fracture in ulcerative colitis: a population-based study from Olmsted County, Minnesota

BACKGROUND & AIMS

Osteopenia is common in patients with ulcerative colitis (UC), but less is known about fracture risk. Previously we were unable to demonstrate increased fractures in a population-based cohort with Crohn's disease.

METHODS

Medical records of 273 Olmsted County, Minnesota residents initially diagnosed with UC in 1940-1993 were reviewed for evidence of subsequent fractures, as were records of a control cohort of county residents matched on age and gender. Cumulative fracture incidence after diagnosis was estimated by using the Kaplan-Meier method. The hazard ratio of fracture in cases relative to control subjects was estimated by Cox proportional hazards regression, which was also used to evaluate potential risk factors for fracture.

RESULTS

Median follow-up was 13 years (range, 1 day-53 years). The cumulative incidence of any fracture from time of diagnosis was 40% at 25 years versus 42% in control subjects (P=0.615). The hazard ratio in cases compared to control subjects was 1.1 (95% confidence interval, 0.8-1.6) for any fracture and 1.3 (95% confidence interval, 0.6-2.8) for any osteoporotic fracture (hip, spine, or wrist as a result of moderate trauma). Other causes of secondary osteoporosis were associated with increased fracture risk, whereas estrogen use was protective. One hundred three cases received any corticosteroids (38%), and 34 (12%) had taken corticosteroids for 6 months or longer. Corticosteroids and bowel resection were not associated with fracture risk.

CONCLUSIONS

In this population-based cohort of patients with UC, fracture risk was not elevated relative to matched community control subjects. Use of corticosteroids did not appear to significantly influence the risk of fracture.

Vitamin D in preventive medicine: are we ignoring the evidence?

Vitamin D is metabolised by a hepatic 25-hydroxylase into 25-hydroxyvitamin D (25(OH)D) and by a renal 1alpha-hydroxylase into the vitamin D hormone calcitriol. Calcitriol receptors are present in more than thirty different tissues. Apart from the kidney, several tissues also possess the enzyme 1alpha-hydroxylase, which is able to use circulating 25(OH)D as a substrate. Serum levels of 25(OH)D are the best indicator to assess vitamin D deficiency, insufficiency, hypovitaminosis, adequacy, and toxicity. European children and young adults often have circulating 25(OH)D levels in the insufficiency range during wintertime. Elderly subjects have mean 25(OH)D levels in the insufficiency range throughout the year. In institutionalized subjects 25(OH)D levels are often in the deficiency range. There is now general agreement that a low vitamin D status is involved in the pathogenesis of osteoporosis. Moreover, vitamin D insufficiency can lead to a disturbed muscle function. Epidemiological data also indicate a low vitamin D status in tuberculosis, rheumatoid arthritis, multiple sclerosis, inflammatory bowel diseases, hypertension, and specific types of cancer. Some intervention trials have demonstrated that supplementation with vitamin D or its metabolites is able: (i) to reduce blood pressure in hypertensive patients; (ii) to improve blood glucose levels in diabetics; (iii) to improve symptoms of rheumatoid arthritis and multiple sclerosis. The oral dose necessary to achieve adequate serum 25(OH)D levels is probably much higher than the current recommendations of 5-15 microg/d.