Genetic factors determine extent of bone loss in inflammatory bowel disease

Bone density improves with disease remission in patients with inflammatory bowel disease

BACKGROUND AND AIMS

Patients with inflammatory bowel disease (IBD) are at risk of low bone mineral density (BMD). The aim of this cross-sectional study was to investigate (i) whether patients with IBD in long-term remission have greater bone density relative to patients with active disease, (ii) the effect of remission on BMD in ulcerative colitis and Crohn's disease, and (iii) the effect of azathioprine treatment, used to induce remission, on BMD.

PATIENTS AND METHODS

BMD relative to the age-standardised mean (Z-score) was measured by dual-energy X-ray absorptiometry at the left femoral neck and lumbar spine in consecutive patients with IBD. Patients were divided into the following groups: (i) active disease, (ii) remission of less than one year, (iii) remission of one to three years, and (iv) remission of more than three years. Active disease was defined as three or more bowel motions per day, treatment with oral or rectal corticosteroids, and/or presence of a fistula. The subgroups with ulcerative colitis and Crohn's disease and the effect of taking azathioprine were compared. All results were controlled for confounding variables. RESULTS A total of 137 (64 ulcerative colitis, 73 Crohn's disease) patients were evaluated. Patients in remission for more than three years had a normal mean Z-score that was significantly higher than those with active disease at both the femoral neck and the lumbar spine for both ulcerative colitis and Crohn's disease. Patients taking azathioprine and in remission had significantly higher mean Z-scores at the lumbar spine than patients with active disease and who were not taking azathioprine.

CONCLUSION

In patients with ulcerative colitis and Crohn's disease, age-matched BMD is higher with increasing duration of disease remission and induction of remission by azathioprine.

Effect of systemic glucocorticoid therapy on bone metabolism and the osteoprotegerin system in patients with active Crohn's disease

BACKGROUND AND AIMS

Osteoporosis may occur in 25-30% of patients with Crohn's disease. Its pathogenesis is not completely understood. Both systemic inflammation in acute disease and treatment with systemic glucocorticoids have been implicated. The aim of the present study was to investigate changes in bone density and biochemical markers of bone metabolism before and during a 3-month period of high-dose glucocorticoid treatment for acute flare-up of Crohn's disease.

METHODS

Twenty-five patients with active Crohn's disease requiring systemic glucocorticoid treatment (prednisolone, 60 mg/day) were investigated. Lumbar spine and femoral neck bone mineral densitometry was performed at baseline and again after 3 months. Clinical examinations including evaluation of the Crohn's disease activity index and measurement of the biochemical markers osteocalcin, deoxypyridinoline, osteoprotegerin and the soluble receptor activator of NF-kappaB ligand were performed prior to, and at 1, 2 and 12 weeks following steroid administration. RESULTS Median lumbar bone mineral density decreased significantly during the observation period by 1.04% from -0.84 (t score; range, -2.8 to +0.57) to -0.95 (range, -3.1 to +0.40; P = 0.022), while bone density of the total femur decreased by 2.9% from -0.83 (range, -2.61 to +1.86) to -0.90 (range, -2.65 to +0.19; P = 0.01). Serum levels of osteocalcin, a bone formation marker, and osteoprotegerin, an anti-resorptive cytokine produced by osteoblasts, decreased after the first 2 weeks of treatment and reached baseline levels after 3 months. No significant change was found for the bone resorption marker deoxypyridinoline, while soluble receptor activator of NF-kappaB ligand, a cytokine promoting bone resorption, tended to increase during steroid treatment.

CONCLUSION

A decrease in bone mineral density in patients with Crohn's disease appears to result, at least in part, from a short-term effect of systemic glucocorticoid. Modulation of osteoclastogenesis by the receptor activator of NF-kappaB ligand/osteoprotegerin cytokine system and decreased osteoblastic function may be the underlying molecular basis.

Association between heat shock protein 72 gene polymorphism and acute renal failure in premature neonates

Heat shock protein (HSP)70 plays an important role in the ischemic tolerance of fetal and neonatal kidney. We have investigated the association of genetic polymorphisms of the constitutive HSP70 (HSP73) and the inducible HSP70 (HSP72) encoding genes with the risk of acute renal failure (ARF) in very low birth weight (VLBW) neonates. Thirty-seven VLBW neonates with ARF and 93 VLBW neonates without ARF were enrolled in the study. The presence of HSP72 (1267)AG and HSP73 (190)GC polymorphism was analyzed from dried blood samples by PCR and restriction length fragment polymorphism. Allelic prevalence was related to reference values obtained in 131 healthy adults. Stepwise binary logistic regression was applied to determine the independent effect of the established risk factors to the development of ARF. Sixteen of 37 VLBW neonates with ARF and 18 of 93 VLBW neonates without ARF were homozygous for HSP72 (1267)G allele (p </= 0.01). The association between HSP72 (1267)GG genotype and ARF remained at the level of significance (p = 0.05) when it was adjusted for established risk factors of neonatal ARF. Prevalence of HSP72 (1267)GG was also higher in VLBW neonates than in the reference population (p < 0.05) and in VLBW neonates with infant respiratory distress syndrome than in those without (p < 0.001). We found that in VLBW neonates carrying HSP72 (1267)GG genetic variation, which is associated with low inducibility of HSP72, the risk of ARF was increased. Therefore, VLBW neonates with (1267)GG might express less HSP72 and might be less protected against ARF.

Inflammatory bowel disease in early childhood and adolescence: special considerations

Several aspects of IBD overlap between pediatric and adult population. Those include nutritional issues, bone density, and medical and surgical therapies. Some aspects like natural course of the disease, and epidemiology and genetics are more easily examined and researched in the pediatric population. Others like pubertal and growth delay, and transition of health care are unique to pediatric patients. This article examines some of the similarities, as well as differences of IBD in these two populations.

What are the major arguments in favour of the genetic susceptibility for inflammatory bowel disease?

Epidemiological data, notably concordance rates in twin pairs and familial aggregation, have provided strong evidence for the importance of the genetic contribution in inflammatory bowel diseases. Genome wide scanning has been remarkably successful in identifying a number of susceptibility loci. The identification of the IBD1 gene on chromosome 16 as NOD2/CARD15 definitely establishes that a significant proportion of Crohn's disease has an underlying genetic cause. In addition, our knowledge of the clinical impact of other genes in modelling disease phenotypes has increased in parallel. These results have led to great optimism that important clinical applications will result from genetic research in the near future.

Bone density in a population-based cohort of premenopausal adult women with early onset inflammatory bowel disease

OBJECTIVE

We aimed to determine the bone mineral density (BMD) using dual energy x-ray absorptiometry in a population-based sample of women with inflammatory bowel disease who were diagnosed before age 20 yr and who are currently premenopausal and less than 45 yr.

METHODS

The University of Manitoba Inflammatory Bowel Disease Epidemiology Research Registry was accessed to find eligible women. Of 171 eligible subjects, 82 agreed to participate, and 70 appeared for dual energy x-ray absorptiometry. All subjects completed demographic, clinical, and lifestyle questionnaires and underwent dual energy x-ray absorptiometry with analyses for both areal and volumetric BMD.

RESULTS

The mean areal T scores at the lumbar spine, femoral neck, total hip, and total body were -0.14 +/- 1.05, -0.15 +/- 1.04, -0.25 +/- 1.17, and +0.09 +/- 1.04, respectively. Forty-five subjects had normal BMD, and 25 had a T score < -1. There were no significant differences between these groups for predictive variables. Only three (4%) had osteoporosis (T score < -2.5 at any site). There were 12 with disease onset before puberty and 58 after puberty. There were no differences between these groups for BMD. Volumetric BMD was slightly higher than areal BMD at the lumbar spine (p < 0.0002), femoral neck (p < 0.01), and total hip (p < 0.001).

CONCLUSIONS

In a population-based sample of women diagnosed with IBD before 20 yr of age and who are currently premenopausal, their average BMD is normal and the prevalence of osteoporosis is very low. Despite the potential for children with IBD to develop osteoporosis, their BMD as adults is generally normal.

Therapy of osteoporosis in patients with Crohn's disease: a randomized study comparing sodium fluoride and ibandronate

BACKGROUND

Osteoporosis is a frequent complication in Crohn's disease. Although the efficacy of both sodium fluoride and aminobisphosphonates in postmenopausal osteoporosis has been investigated in long-term therapy studies, no long-term results are available regarding the effect of these agents in the management of osteoporosis in patients with Crohn's disease.

METHODS

Eighty-four patients with Crohn's disease and pathological bone mineral density findings were randomized to receive either vitamin D3 (1000 IU) and calcium citrate (800 mg) daily (group A) or sodium fluoride (25 mg b.d., group B) or intravenous ibandronate (1 mg every 3 months, group C) in addition to daily calcium/vitamin D substitution. On admission to the study and after 12 and 27 months, patients underwent dual-energy X-ray absorptiometry and radiological examination of the spine.

RESULTS

Sixty-eight patients completed the 1-year observation period and were available for the intention-to-treat analysis. No new vertebral fractures were diagnosed. In group A, lumbar bone density increased by 2.6% (P = 0.066, N.S.), in group B by 5.7% (P = 0.003) and in group C by 5.4% (P = 0.003). Therapy with sodium fluoride was associated with an increase in osteocalcin (N.S.), whereas administration of ibandronate was associated with a decrease in the resorption parameter, carboxy-terminal cross-linked type-I collagen telopeptide (P < 0.05). Both sodium fluoride and ibandronate resulted in significant decreases in the serum concentration of osteoprotegerin after 9 months (P < 0.001).

CONCLUSIONS

The findings of the present study show that both sodium fluoride and ibandronate are effective in combination with calcium and vitamin D substitution in the management of osteopenia and osteoporosis in patients with Crohn's disease. Both agents are safe and well tolerated, and induce continuous increases in lumbar bone density.

Cortical bone resorption during exercise is interleukin-6 genotype-dependent

The objective of this study was to examine the relationship between the interleukin-6 (IL-6) -174 G>C promoter polymorphism and exercise-induced femoral cortical bone resorption. Skeletal response to exercise was assessed in 130 male Caucasian army recruits. Five cross-sectional magnetic resonance images of the right femur were obtained before and after a 10-week period of basic physical training, and changes in cross-sectional cortical area were calculated. Recruits were genotyped for the -174 G>C IL-6 promoter polymorphism. Genotype frequencies (GG 36%, GC 47%, CC 22.17%) were in Hardy-Weinberg equilibrium. The mean percentage change in proximal femoral cross-sectional cortical area was strongly IL-6 genotype-dependent, with GG homozygotes losing 6.8 (3.82)% in cortical area, GC gaining+5.5 (4.88)% and CC gaining+17.3 (9.46)% (P=0.007 for linear trend). These changes persisted throughout the right femur and were significant in the femur as a whole (P=0.03). This study demonstrates an association between a functional polymorphism in the IL-6 gene and femoral cortical remodelling during strenuous physical exercise. Previous studies have suggested an important role for IL-6 in the regulation of bone mass in postmenopausal women, and in the invasion of bone by metastatic tumour deposits. These data extend these observations to the regulation of bone mass in healthy males, supporting a fundamental role for IL-6 in the regulation of bone mass and bone remodelling in humans.

Heat shock protein 70 genotypes HSPA1B and HSPA1L influence cytokine concentrations and interfere with outcome after major injury

OBJECTIVE

To examine the influence of genetic variations in heat shock proteins on trauma outcome.

DESIGN

Prospective, noninterventional, single-center study.

SETTING

Level I trauma center.

SUBJECTS

Eighty consecutive severe multiple trauma patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma concentrations of interleukin-6 and tumor necrosis factor-alpha were measured over a 5-day course by chemiluminescence-immunoassay. The genotypes of the polymorphisms HSPA1B (HSP70-2) G1538A and HSPA1L (HSP70-Hom) C2437T were determined by polymerase chain reaction and restriction cleavage with PstlI or NcoI, respectively. Allele frequency of the HSPA1B 1538 G allele was 0.569, and that of the HSPA1L 2437 T allele was 0.821. Interleukin-6 concentrations rapidly increased and dropped to almost normal after 5 days, whereas tumor necrosis factor-alpha concentrations increased until day 5. Patients carrying the genotypes HSPA1B AG or HSPA1L CT had significantly higher plasma concentrations of tumor necrosis factor-alpha and interleukin-6 compared with those with genotype GG or TT. Presence of the HSPA1L genotype CT also was a significant risk factor to develop liver failure (odds ratio, 4.6; 95% confidence interval, 1.5-14.1) and to acquire at least one complication severe enough to score three points according to the Denver multiple organ failure score (odds ratio, 3.0; 95% confidence interval, 1.1-9.2).

CONCLUSION

The data indicate that genetic variations of the heat shock proteins HSPA1B and HSPA1L may contribute to clinical outcome after severe injury.

Examination, prevention and treatment of osteoporosis in patients with inflammatory bowel disease: recommendations and reality

BACKGROUND

Patients with inflammatory bowel disease (IBD) are at increased risk of developing osteopenia and osteoporosis. Our aim was to evaluate the current practices of examination, prevention and treatment of osteoporosis in IBD patients in a routine clinical setting.

METHODS

A total of 154 consecutive patients with IBD (63 female, 91 male; 36 ulcerative colitis, 115 Crohn's disease, 3 indeterminate colitis), referred to two gastroenterological units for scheduled follow-up examinations, were included. Patient charts were evaluated regarding bone densitometry already performed and any prophylactic or therapeutic interventions in cases of low bone mineral density.

RESULTS

Bone mineral density (BMD) measurements had been performed only in 38 patients (25%). BMD was abnormally low in 27 of the examined patients (71%), 20 of whom had osteopenia and seven had osteoporosis. Among the subgroup of patients on long-term steroid therapy (77 patients), 30 had been referred to bone densitometry during the course of disease, and 21 of them were found to have low bone mineral density. Preventive measures were prescribed in 12 patients (9% of the whole study population). In the majority of the patients with low bone mineral density, calcium and vitamin D were used as treatment.

CONCLUSIONS

Despite the high prevalence of osteopenia and osteoporosis in patients with IBD, only a minority of these patients were included in a structured program in accordance with modern guidelines for diagnosing and preventing this extraintestinal complication in a routine clinical setting.

Long-term fracture risk in patients with Crohn's disease: a population-based study in Olmsted County, Minnesota

BACKGROUND & AIMS

Osteoporosis is common in patients with Crohn's disease, but less is known about their risk of actual fractures.

METHODS

The medical records of all 238 Olmsted County, Minnesota, residents diagnosed with Crohn's disease between 1940 and 1993 were reviewed for evidence of subsequent fractures compared with a control group of county residents matched by age and sex. The risk ratio of fracture in patients relative to controls was estimated using the Cox proportional hazards regression model. The cumulative incidence of fracture following diagnosis was estimated using the Kaplan-Meier method.

RESULTS

Sixty-three patients had 117 different fractures. The cumulative incidence of any fracture from the time of diagnosis onward was 36% at 20 years versus 32% in controls (P = 0.792). Compared with controls, the overall risk ratio for any fracture was 0.9 (95% confidence interval [CI], 0.6-1.4), whereas the relative risk for an osteoporotic fracture was 1.4 (95% CI, 0.7-2.7). The risk ratio for thoracolumbar vertebral fracture was 2.2 (95% CI, 0.9-5.5). Cox proportional hazards regression identified only age as a significant clinical predictor of fracture risk (hazard ratio per 10-year increase in age, 1.3; 95% CI, 1.1-1.5). Specifically, use of corticosteroids and surgical resection did not predict risk of fracture among these unselected patients with Crohn's disease from the community.

CONCLUSIONS

In this population-based inception cohort of patients with Crohn's disease, the risk of fracture was not elevated relative to age- and sex-matched controls.

Osteoporosis and other complications of inflammatory bowel disease

Osteoporosis has received increasing attention as a potential complication of inflammatory bowel disease (IBD). The first population-based data on incidence of fractures in an IBD population were published this past year. The incidence of fractures was one per 100 patient years. Compared with the general population, the fracture rate was increased; however, the relative risk was 1.4 and, therefore, not as high as might be expected from the myriad of studies reporting high rates of osteopenia measured by dual energy x-ray absorptiometry (DXA). Another area receiving increasing attention is that of the enhanced risk of venous thrombosis in patients with IBD. The first population-based incidence rates of venous thrombosis in IBD were also published this past year and showed that IBD patients are affected by venous thrombosis at a rate of approximately one per 200 patient years. The relative risk for venous thrombosis compared with the general population was 3.5. Several studies have reported on associated risk markers or genetic clotting abnormalities, but no clear paradigm has emerged to account for those patients who will suffer a clot. Finally, the first North American population-based study was published, quantifying the prevalence rates of extraintestinal manifestations in patients with IBD for at least 10 years. Some gender- and disease-specific findings emerged. This study found that iritis and uveitis were more common in female patients with ulcerative colitis (3.2%), primary sclerosing cholangitis (PSC) was most common in male patients with ulcerative colitis (3%), ankylosing spondylitis was most common in male patients with Crohn disease (2.7%), and erythema nodosum was most likely to occur in female patients with Crohn disease (1.9%).

Metabolic Bone Disease in Inflammatory Bowel Disease

An oral calcium supplement (1000 mg/day) is recommended. Regular exercise should be performed. Ethanol intake should be moderate. Protein intake should be moderate. The patient's vitamin D status should be determined and corrected with an oral supplement when deficiency is present. Baseline and yearly bone density measurement should be taken. Alendronate, 10 mg/d orally, or risedronate, 5 mg/d orally, should be given to patients with osteopenia. Use of corticosteroids, cyclosporin, tacrolimus, and methotrexate should be limited to the short term when possible. Estrogen replacement therapy is recommended in postmenopausal women unless contraindications exist.

Bone mineral density in Crohn's disease: a longitudinal study of budesonide, prednisone, and nonsteroid therapy

OBJECTIVE

Corticosteroids may contribute to the bone loss associated with Crohn's disease (CD). We investigated the effect on bone mineral density (BMD) of treatment with budesonide, a steroid with low systemic activity, and compared the outcome with prednisone and nonsteroid therapy in patients with CD.

METHODS

Prospective annual BMDs of the lumbar spine (LS) and femoral neck (FN) were measured for 2 yr in 138 patients with quiescent CD treated with mean daily doses of 8.5 mg of budesonide (n = 48), 10.5 mg of prednisone (n = 45), or nonsteroid drugs (n = 45).

RESULTS

Between baseline and 1 yr, the mean LS BMD decreased 2.36% in the budesonide group (p < 0.001), 0.61% in the prednisone group (ns), and 0.09% in the nonsteroid group (ns). The difference between budesonide and nonsteroid groups was significant (p = 0.003). In the 2nd yr, LS BMD did not change in the three groups. After 2 yr, FN BMD decreased 2.94% in the budesonide group (p < 0.01), 0.36% in the prednisone group (ns), and 1.05% in the nonsteroid group (ns); the differences among groups were not significant. The proportion of patients with bone loss of >2% per annum at the LS and FN was higher in the budesonide group than in the nonsteroid group (p < 0.001) and prednisone group (p < 0.05).

CONCLUSIONS

Patients with CD receiving maintenance treatment for 2 yr with prednisone show little change in BMD, whereas treatment with budesonide may be associated with LS and FN bone loss. Budesonide does not confer an advantage over low-dose prednisone for the preservation of BMD.

Extraintestinal manifestations of inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) may confront a variety of nonintestinal problems. The first North American population-based data describing the incidence rates of several of these disorders have been reported over the past year. Reports have also documented our expanding knowledge of peristomal pyoderma gangrenosum, and of ulcerative colitis following liver transplantation in patients with primary sclerosing cholangitis. Osteopenia continues to receive considerable attention. Factors such as osteoprotegrin ligand, and its interaction with receptor activator of nuclear factor kappa B, are connected with T-cell activity, inflammation, and osteoclastogenesis. Studies in these and other areas are addressed in this review.

Extraintestinal Complications of Inflammatory Bowel Disease

Extraintestinal complications of inflammatory bowel disease (IBD) are often secondary to the underlying disease. Therefore, the first priority is to get active IBD into remission with medications, since surgery for IBD is not indicated for the treatment of extraintestinal complications. Symptoms of extraintestinal complications usually can be treated with simple agents; the treatment of patients with refractory symptoms and the use of more complex drug regimens should be done in cooperation with specialists on affected organ systems. Careful consideration of prescribed drugs is necessary because they may negatively influence the course of IBD.