Vitamin D status and measurements of markers of bone metabolism in patients with small intestinal resection.

BACKGROUND AND AIMS: Vitamin D deficiency is common in patients with small intestinal resection and may lead to secondary hypersecretion of parathyroid hormone (PTH), which in turn may result in increased bone turnover rate and loss of bone mineral. The aims of this study were to investigate the prevalence of vitamin D deficiency, as assessed by low serum concentrations of 25-hydroxyvitamin D (25(OH)D) in patients with small intestinal resection and to explore the relation of 25(OH)D to PTH, markers of bone turnover rate, and bone mineral density (BMD) in these patients. PATIENTS: Forty two patients with small intestinal resection, a faecal energy excretion of more than 2.0 MJ/day, and a mean length of the remaining small intestine of 199 cm were included. Diagnoses were Crohn's disease (n=35) and other (n=7). METHODS: 25(OH)D was analysed by radioimmunoassay and bone turnover rate was assessed by measurement of serum osteocalcin, serum alkaline phosphatase, urine pyridinoline, and urine deoxypyridinoline. BMD was measured by dual energy x ray absorptiometry. RESULTS: Mean 25(OH)D concentration was 13.4 (SD 9.7) ng/ml, which was significantly below the reference mean of 26.4 (SD 13.2) ng/ml (p<0.001). Vitamin D deficiency (25(OH)D concentration

Short-term administration of glucagon-like peptide-2. Effects on bone mineral density and markers of bone turnover in short-bowel patients with no colon.

BACKGROUND: Glucagon-like peptide 2 (GLP-2) is a newly discovered intestinotrophic hormone. We have recently reported that a 5-week GLP-2 treatment improved the intestinal absorptive capacity of short-bowel patients with no colon. Additionally, GLP-2 treatment was associated with changes in body composition that included a significant increase in total body bone mass. This article describes the effect of GLP-2 on spinal and hip bone mineral density (BMD) and biochemical markers of bone turnover in these patients. METHODS: In an open-labelled pilot study, eight short-bowel patients (3M, 5F; mean age 49 years) with small-bowel resection and no colon received 400 microg s.c. of GLP-2 twice daily for 5 weeks. Four received home parenteral nutrition (mean length of residual jejunum 83 cm) and 4 did not (mean length of ileum resected 106 cm). The outcome measures were the mean percent change from baseline in spinal and hip BMD measured by dual-energy X-ray absorptiometry, changes in four biochemical markers of bone-turnover, PTH, 25-hydroxy vitamin-D, and the intestinal absorption of calcium. RESULTS: Mean +/- s(x) (SEM) percent changes in spinal and hip BMD were 1.1+/-0.4% (P < 0.05) and 1.9+/-0.8% (P = 0.06), respectively. The intestinal calcium absorption increased by 2.7% (P = 0.87). Serum ionized calcium increased in 5/8 patients with a concomitant decrease in serum PTH values. Three of the four markers of bone turnover decreased. CONCLUSION: A 5-week GLP-2 administration significantly increased spinal BMD in short-bowel patients with no colon. The mechanism by which GLP-2 affects bone metabolism remains unclear, but may be related to an increased mineralization of bone resulting from an improved intestinal calcium absorption.

Alendronate increases lumbar spine bone mineral density in patients with Crohn's disease.

BACKGROUND & AIMS: Low bone mineral density (BMD) is a common complication of Crohn's disease and may lead to increased morbidity and mortality because of fractures. We investigated the effect of treatment with the bisphosphonate alendronate on bone mass and markers of bone remodeling in patients with Crohn's disease. METHODS: A 12-month double-blind, randomized, placebo-controlled trial examined the effect of a 10-mg daily dose of alendronate. Thirty-two patients with a bone mass T score of -1 of the hip or lumbar spine were studied. The main outcome measure was the difference in the mean percent change in BMD of the lumbar spine measured by dual-energy x-ray absorptiometry. Secondary outcome measures included changes in BMD of the hip and total body and biochemical markers of bone turnover (S-osteocalcin, urine pyridinoline, and urine deoxypyridinoline excretion). RESULTS: Mean (+/-SEM) BMD of the lumbar spine showed an increase of 4.6% +/- 1.2% in the alendronate group compared with a decrease of 0.9% +/- 1.0% in patients receiving placebo (P < 0.01). BMD of the hip increased by 3.3% +/- 1.5% in the alendronate group compared with a smaller increase of 0.7% +/- 1.1% in the placebo group (P = 0.08). Biochemical markers of bone turnover decreased significantly in the alendronate group (P < 0.001). Alendronate was well tolerated, and there was no difference in adverse events among treatment groups. CONCLUSIONS: Treatment with alendronate, 10 mg daily, significantly increased BMD in patients with Crohn's disease and was safe and well tolerated.

Absorption of calcium and magnesium in patients with intestinal resections treated with medium chain fatty acids.

BACKGROUND: Steatorrhoea is associated with increased faecal loss of calcium and magnesium. Medium chain C8-C10 triglycerides (MCTs) improve fat absorption in patients with small bowel resections but the effects on intestinal absorption of divalent cations are not clear. AIM: To assess the effect of dietary replacement of long chain triglycerides (LCTs) with MCTs on calcium and magnesium absorption in patients with small bowel resections. PATIENTS: Nineteen adult patients with a remaining small intestine averaging 171 cm (range 50-300). METHODS: In a crossover design, patients were randomised to two high fat diets (10 MJ/day, 50% as fat) for four days each separated by one day of washout. Diets were prepared in duplicate and were based on either LCT (LCT period) or equal quantities of LCT and MCT (L/MCT period). Metabolic balances were calculated during the last three days of each period. RESULTS: Mean stool volume increased significantly with the L/MCT diet and was 336 ml more than that with the LCT diet (95% confidence interval of mean difference, 26-649 ml). There was no significant change in the net absorption of calcium and magnesium between the two diets. On average, percentage calcium absorption was 8.6% with the LCT diet and 12.5% with the L/MCT diet. Mean percentage magnesium absorption was 5.4% with the LCT diet and 2.9% with the L/MCT diet. CONCLUSIONS: Dietary replacement of 50% long chain triglycerides with medium chain triglycerides in small bowel resected patients increased faecal volume significantly. No changes in the intestinal net absorption of calcium and magnesium were demonstrated.

Comparison of dual-energy X-ray absorptiometry to four other methods to determine body composition in underweight patients with chronic gastrointestinal disease.

Assessment of body composition may provide important information about the nutritional status. The applicability of two safe and convenient methods for body composition analysis, bioelectrical impedance analysis (BIA) and dual-energy x-ray absorptiometry (DXA), in underweight patients with chronic gastrointestinal disease has been sparsely elucidated. Our objective was to compare measurements by DXA with four other methods. Furthermore, we compared total body water (TBW) by BIA using three different BIA equations with measurement of TBW by tritium dilution (TBW-3H2O). Nineteen clinically stable underweight patients with chronic gastrointestinal disease were included in the study (body mass index [BMI], 19.3 +/- 1.2 kg/m2). Body composition was assessed using total body potassium (TBK), isotope dilution of tritium (3H2O), anthropometry (skinfold thickness [SF]), BIA, and DXA. Fat-free mass (FFM) by DXA was in reasonable agreement with body composition measurements by TBK (mean difference(TBK-DXA) = -1.61 kg, r = .88, standard error of the estimate [SEE] = 4.66 kg) and 3H2O (mean difference(3H2O-DXA) = 0.98 kg, r = .93, SEE = 3.34 kg). Although mean values for FFM by DXA differed significantly versus BIA and SF, we found highly significant correlations between the measurements (r = .97 and r = .97, respectively). The mean TBW by BIA was overestimated by 1.9 and 3.1 L compared with TBW-3H2O when prediction equations for normal-weight subjects were used. We conclude that the DXA method is a valuable addition to the list of methods available for body composition studies in clinically stable underweight patients. Our data show that BIA equations for normal-weight subjects overestimated TBW in the patients studied.

Does paracentesis of ascites influence measurements of bone mineral or body composition by dual-energy x-ray absorptiometry?

Measurements of bone mineral content (BMO) and density (BMD) by dual-energy x-ray absorptiometry (DXA) may be affected by changes in soft tissue overlying bone. Furthermore, the accuracy error for body composition determined by DXA may be high in the trunk region due to the complex bone geometry. Our objective was to evaluate the impact of paracentesis on measurements of bone mineral and body composition by DXA. DXA (Norland XR-36; Norland, Fort Atkinson, WI) scans were performed in six patients with cirrhosis of the liver before and after treatment of ascites by paracentesis. There were no significant differences in the spinal BMC (change [delta] = 0.04%) and BMD (delta = -0.9%) (P > .05), nor in total body BMC ([TBBMC] delta = 1.9%) and BMD ([TBBMD] delta = 0.4%) (P > .05). The median volume of ascites drained (6.8 L; range, 1.6 to 14.7) was not significantly different from the median change in total (5.8 kg; range, 2.0 to 16.1) or trunk lean tissue mass ([LTM] 5.8 kg; range, 1.9 to 11.9) (P > .05). The changes in body weight correlated with the changes in trunk LTM (r = .93, standard error of the estimate [SEE] = 1.8 kg, P = .007). Total and regional fat mass were not changed significantly by the paracentesis. We conclude that measurements of total body and spinal bone mineral by DXA are unaffected by large changes in the soft tissue composition and height of the trunk. Furthermore, the change in body composition induced by ascites drainage was accurately determined as a change in total body and trunk LTM on a group level.

Paracetamol metabolism in patients with ulcerative colitis.

AIMS: The capacity for sulphation of phenols appears to be impaired in the colonic mucosa of patients with ulcerative colitis. The aim of the present study was to investigate the systemic capacity for sulphation of phenols in patients with ulcerative colitis assessed by the metabolic clearances of paracetamol to the sulphate, glucuronide and glutathione derived metabolites. METHODS: Ten patients with ulcerative colitis and 10 control subjects received a single oral dose of paracetamol (1 g). Venous blood samples were collected frequently for pharmacokinetic determinations (one compartment model). Urine was collected for 24 h. Plasma samples were analysed for parent drug and urine samples for parent drug and metabolites by h.p.l.c. Partial metabolic clearances were calculated as the fractional urinary recovery of each conjugate multiplied by the apparent oral clearance of paracetamol. RESULTS: The apparent oral clearance of paracetamol and the partial clearances of its metabolites were not significantly different between the two study groups. Median value and the corresponding 25th and 75th percentiles for the clearance of the sulphate metabolites were 93.6 (82.5-138.8) ml kg(-1)h(-1) and 77.4 (75.5-99.1), patients with ulcerative colitis and control subjects, respectively. CONCLUSIONS: These results do not indicate a general impairment of the systemic capacity for sulphation of paracetamol in patients with ulcerative colitis.