Race and fistulizing perianal Crohn's disease.

BACKGROUND: There is increasing recognition of Crohn's disease (CD) in non-white populations. However, reports of racial disparities in the phenotype of CD are still inconsistent. AIM: : The aim of this study was to test the hypothesis that African American (AA) patients have higher incidence of severe fistulizing perianal Crohn's disease (FPD) compared with white patients. METHODS: Cross-sectional analysis of 333 adult CD patients treated at The Mount Sinai Hospital with infliximab between May 2011 and December 2011 was conducted. Self-reported race/ethnicity was recorded and proportions of each group with FPD were compared across the population. RESULTS: Among all 333 evaluable CD patients on infliximab, 73.6% were white, 11.4% AA, 13.2% Hispanic, and 1.8% Asian. Of these 333 patients, 88 had FPD: only 48 of these (54.5%) were white, whereas fully 18 (20.5%) were AA, 20 (22.7%) were Hispanic, and 2 (2.3%) were Asian. Thus, patients receiving infliximab for FPD were significantly more likely to be AA or Hispanic than white (AA vs. whites: risk ratio=2.63; 95% confidence interval, 1.74-3.96; P=<0.0001; Hispanics vs. whites: risk ratio=2.32; 95% confidence interval, 1.54-3.50; P=0.0001). There was no statistically significant difference between AA and Hispanics. CONCLUSION: CD patients at our medical center with FPD requiring infliximab therapy were significantly more likely to be AA or Hispanic.

Genetic variation in the patterns of skeletal progenitor cell differentiation and progression during endochondral bone formation affects the rate of fracture healing.

These studies examined how genetic differences that regulate architectural and bone material properties would be expressed during fracture healing and determine whether any of these features would affect rates of healing as defined by regain of strength. Controlled fractures were generated in three inbred strains of mice: A/J, C57Bl/6J (B6), and C3H/HeJ (C3H). Both the A/J and B6 strains showed faster healing than the C3H strain based on regains in strength and stiffness. Strain-specific architectural features such as moment of inertia, cross-sectional area, and cortical thickness were all recapitulated during the development of the callus tissues. None of these traits were directly relatable to rates of fracture healing. However, rates of healing were related to variations in the temporal patterns of chondrogenic and osteogenic lineage development. The B6 strain expressed the highest percentage of cartilage gene products and had the longest period of chondrocyte maturation and hypertrophy. The slowest healing strain (C3H) had the shortest period of chondrogenic development and earliest initiation of osteogenic development. Although the A/J strain showed an almost identical pattern of chondrogenic development as the C3H strain, A/J initiated osteogenic development several days later than C3H during fracture healing. Long bone growth plates at 28 days after birth showed similar strain-specific variation in cartilage tissue development as seen in fracture healing. Thus, the B6 strain had the largest growth plate heights, cell numbers per column, and the largest cell size, whereas the C3H columns were the shortest, had the smallest number of cells per column, and showed the smallest cell sizes. These results show that (1) different strains of mice express variations of skeletal stem cell lineage differentiation and (2) that these variations affect the rate of fracture healing.