Context: In primary hyperparathyroidism (PHPT) bone mineral density (BMD) is typically decreased in cortical bone and relatively preserved in trabecular bone. An increased fracture rate is observed... Show moreContext: In primary hyperparathyroidism (PHPT) bone mineral density (BMD) is typically decreased in cortical bone and relatively preserved in trabecular bone. An increased fracture rate is observed however not only at peripheral sites but also at the spine, and fractures occur at higher BMD values than expected. We hypothesized that components of bone quality other than BMD are affected in PHPT as well.Objective: To evaluate bone material properties using impact microindentation (IMI) in PHPT patients.Methods: In this cross-sectional study, the Bone Material Strength index (BMSi) was measured by IMI at the midshaft of the tibia in 37 patients with PHPT (28 women), 11 of whom had prevalent fragility fractures, and 37 euparathyroid controls (28 women) matched for age, gender, and fragility fracture status.Results: Mean age of PHPT patients and controls was 61.813.3 and 61.0 +/- 11.8 years, respectively, P = .77. Calcium and PTH levels were significantly higher in PHPT patients but BMD at the lumbar spine (0.92 +/- 0.15 vs 0.89 +/- 0.11, P = .37) and the femoral neck (0.70 +/- 0.11 vs 0.67 +/- 0.07, P = .15) were comparable between groups. BMSi however was significantly lower in PHPT patients than in controls (78.2 +/- 5.7 vs 82.8 +/- 4.5, P < .001). In addition, BMSi was significantly lower in 11 PHPT patients with fragility fractures than in the 26 PHPT patients without fragility fractures (74.7 +/- 6.0 vs 79.6 +/- 5.0, P = .015).Conclusion: Our data indicate that bone material properties are altered in PHPT patients and most affected in those with prevalent fractures. IMI might be a valuable additional tool in the evaluation of bone fragility in patients with PHPT. Show less
In this thesis, we evaluated the acute and more long-term effects of different weight loss strategies; pure calorie restriction by very low calorie diet and gastric banding, versus the drastic... Show moreIn this thesis, we evaluated the acute and more long-term effects of different weight loss strategies; pure calorie restriction by very low calorie diet and gastric banding, versus the drastic surgical procedure Roux-en-Y gastric bypass. Moreover, we found differences between NGT and T2DM subjects at baseline, which enable us to better be able to dissect the subsequent effects of the procedures. To our surprise, and in contrast to previous studies, we observed no additional effect of the RYGB as compared to calorie restriction, on our main outcome parameters: postprandial glucose, insulin and the gut peptide levels three weeks after surgery. Furthermore, both restrictive and RYGB induced weight loss resulted in comparable effects on the lipidome, circulating thyroid hormone levels and the autonomic nervous system. For these outcome parameters, it seems that calorie restriction is the common denominator of the effect of the different weight loss strategies on the short term. Clearly distinct effects of RYGB, however, were seen on bile salt, FGF21 and glucagon levels in response to food intake. Although neither the exact mechanisms, nor the eventual metabolic effect are as yet clear, the gut-liver-pancreas axis may be an important mediator of the effect of the RYGB Show less
