Effects of Circulating and Local Uteroplacental Angiotensin II in Rat Pregnancy.

The renin-angiotensin (Ang) system is important during placental development. Dysregulation of the renin-Ang system is important in preeclampsia (PE). Female rats transgenic for the human angiotensinogen gene crossed with males transgenic for the human renin gene develop the PE syndrome, whereas those of the opposite cross do not. We used this model to study the role of Ang II in trophoblast invasion, which is shallow in human PE but deeper in this model. We investigated the following groups: PE rats, opposite-cross rats, Ang II–infused rats (1000 ng/kg per day), and control rats. Ang II infusion increased only circulating Ang II levels (267.82 pg/mL), opposite cross influenced only uteroplacental Ang II (13.52 fmol/mg of protein), and PE increased both circulating (251.09 pg/mL) and uteroplacental (19.24 fmol/mg of protein) Ang II. Blood pressure and albuminuria occurred in the models with high circulating Ang II but not in the other models. Trophoblast invasion increased in PE and opposite-cross rats but not in Ang II–infused rats. Correspondingly, uterine artery resistance index increased in Ang II–infused rats but decreased in PE rats. We then studied human trophoblasts and villous explants from first-trimester pregnancies with time-lapse microscopy. Local Ang II dose-dependently increased migration by 75%, invasion by 58%, and motility by 282%. The data suggest that local tissue Ang II stimulates trophoblast invasion in vivo in the rat and in vitro in human cells, a hitherto fore unrecognized function. Conceivably, upregulation of tissue Ang II in the maternal part of the placenta represents an important growth factor for trophoblast invasion and migration

Vascular channels in metacarpophalangeal joints:a comparative histologic and high-resolution imaging study

We evaluated whether cortical interruptions classified as vascular channel (VC) on high-resolution peripheral quantitative computed tomography (HR-pQCT) could be confirmed by histology. We subsequently evaluated the image characteristics of histologically identified VCs on matched single and multiplane HR-pQCT images. Four 3-mm thick portions in three anatomic metacarpophalangeal joint specimens were selected for histologic sectioning. First, VCs identified with HR-pQCT were examined for confirmation on histology. Second and independently, VCs identified by histology were matched to single and multiplane HR-pQCT images to assess for presence of cortical interruptions. Only one out of five cortical interruptions suggestive for VC on HR-pQCT could be confirmed on histology. In contrast, 52 VCs were identified by histology of which 39 (75%) could be classified as cortical interruption or periosteal excavation on matched single HR-pQCT slices. On multiplane HR-pQCT images, 11 (21%) showed a cortical interruption in at least two consecutive slices in two planes, 36 (69%) in at least one slice in two planes and five (10%) showed no cortical interruption. Substantially more VCs were present in histology sections than initially suggested by HR-pQCT. The small size and heterogeneous presentation, limit the identification as VC on HR-pQCT.</p

Recruitment, augmentation and apoptosis of rat osteoclasts in 1,25-(OH)2D3 response to short-term treatment with 1,25-dihydroxyvitamin D3in vivo

Background Although much is known about the regulation of osteoclast (OC) formation and activity, little is known about OC senescence. In particular, the fate of of OC seen after 1,25-(OH)2D3 administration in vivo is unclear. There is evidence that the normal fate of OC is to undergo apoptosis (programmed cell death). We have investigated the effect of short-term application of high dose 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on OC apoptosis in an experimental rat model. Methods OC recruitment, augmentation and apoptosis was visualised and quantitated by staining histochemically for tartrate resistant acid phosphatase (TRAP), double staining for TRAP/ED1 or TRAP/DAPI, in situ DNA fragmentation end labelling and histomorphometric analysis. Results Short-term treatment with high-dose 1,25-(OH)2D3 increased the recruitment of OC precursors in the bone marrow resulting in a short-lived increase in OC numbers. This was rapidly followed by an increase in the number of apoptotic OC and their subsequent removal. The response of OC to 1,25-(OH)2D3 treatment was dose and site dependent; higher doses producing stronger, more rapid responses and the response in the tibiae being consistently stronger and more rapid than in the vertebrae. Conclusions This study demonstrates that (1) after recruitment, OC are removed from the resorption site by apoptosis (2) the combined use of TRAP and ED1 can be used to identify OC and their precursors in vivo (3) double staining for TRAP and DAPI or in situ DNA fragmentation end labelling can be used to identify apoptotic OC in vivo

Long-term functional outcome of distal radius fractures is associated with early post-fracture bone stiffness of the fracture region:An HR-pQCT exploratory study

\u3cp\u3eIdentifying determinants of long-term functional outcome after a distal radius fracture is challenging. Previously, we reported on the association between early HR-pQCT measurements and clinical outcome 12 weeks after a conservatively treated distal radius fracture. We extended the follow-up and assessed functional outcome after two years in relation to early HR-pQCT derived bone parameters. HR-pQCT scans of the fracture region were performed in 15 postmenopausal women with a distal radius fracture at 1-2 (baseline), 3-4 weeks and 26 months post-fracture. Additionally, the contralateral distal radius was scanned at baseline. Bone density, micro-architecture parameters and bone stiffness using micro-finite element analysis (μFEA) were evaluated. During all visits, wrist pain and function were assessed using the patient-rated wrist evaluation questionnaire (PRWE), quantifying functional outcome with a score between 0 and 100. Two-year PRWE was associated with torsional and bending stiffness 3-4 weeks post-fracture (R2: 0.49, p = 0.006 and R2: 0.54, p = 0.003, respectively). In contrast, early micro-architecture parameters of the fracture region or contralateral bone parameters did not show any association with long-term outcome. This exploratory study indicates that HR-pQCT with μFEA performed within four weeks after a distal radius fracture captures biomechanical fracture characteristics that are associated with long-term functional outcome and therefore could be a valuable early outcome measure in clinical trials and clinical practice.\u3c/p\u3

The Feasibility of High-Resolution Peripheral Quantitative Computed Tomography (HR-pQCT) in Patients with Suspected Scaphoid Fractures

Introduction: Diagnosing scaphoid fractures remains challenging. High-resolution peripheral quantitative computed tomography (HR-pQCT) might be a potential imaging technique, but no data are available on its feasibility to scan the scaphoid bone in vivo. Methodology: Patients (≥18 years) with a clinically suspected scaphoid fracture received an HR-pQCT scan of the scaphoid bone (three 10.2-mm stacks, 61-μm voxel size) with their wrist immobilized with a cast. Scan quality assessment and bone contouring were performed using methods originally developed for HR-pQCT scans of radius and tibia. The contouring algorithm was applied on coarse hand-drawn pre-contours of the scaphoid bone, and the resulting contours (AUTO) were manually corrected (sAUTO) when visually deviating from bone margins. Standard morphologic analyses were performed on the AUTO- and sAUTO-contoured bones. Results: Ninety-one patients were scanned. Two out of the first five scans were repeated due to poor scan quality (40%) based on standard quality assessment during scanning, which decreased to three out of the next 86 scans (3.5%) when using an additional thumb cast. Nevertheless, after excluding one scan with an incompletely scanned scaphoid bone, post hoc grading revealed a poor quality in 14.9% of the stacks and 32.9% of the scans in the remaining 85 patients. After excluding two scans with contouring problems due to scan quality, bone indices obtained by AUTO- and sAUTO-contouring were compared in 83 scans. All AUTO-contours were manually corrected, resulting in significant but small differences in densitometric and trabecular indices (<1.0%). Conclusions: In vivo HR-pQCT scanning of the scaphoid bone is feasible in patients with a clinically suspected scaphoid fracture when using a cast with thumb part. The proportion of poor-quality stacks is similar to radius scans, and AUTO-contouring appears appropriate in good- and poor-quality scans. Thus, HR-pQCT may be promising for diagnosis of and microarchitectural evaluations in suspected scaphoid fractures

Evaluation of patients with a recent clinical fracture and osteoporosis, a multidisciplinary approach

The aetiology of osteoporotic fractures is multifactorial, but little is known about the way to evaluate patients with a recent clinical fracture for the presence of secondary osteoporosis

Timing of Subsequent Fractures after an Initial Fracture

A prior fracture is a well-documented risk factor for a subsequent fracture and it doubles the risk of subsequent fractures. Few studies have investigated the time that elapses between the initial and subsequent fracture. These studies show that the subsequent fracture risk is not constant, but fluctuates over time. The risk of subsequent vertebral, hip, and nonvertebral non-hip fractures is highest immediately after initial hip, clinical, and radiographic vertebral fractures and nonvertebral fractures and declines afterward, regardless of gender, age, and initial fracture location. These studies indicate the need for early action after an initial fracture with medical interventions that have an effect within a short term to reduce the preventable risks of subsequent fractures

Patient preference and acceptability of calcium plus vitamin D3 supplementation: a randomised, open, cross-over trial

Preference for a drug formulation is important in adherence to long-term medication for chronic illnesses such as osteoporosis. We investigated the preference for and acceptability of chewable tablet containing calcium and vitamin D (Calci Chew D3, Nycomed) compared to that of a sachet containing calcium and vitamin D3 (Cad, Will-Pharma). This open, randomised, cross-over trial was set up to compare the preference and acceptability of two calcium plus vitamin D3 formulations (both with 500 mg calcium and 400/440 IU vitamin D3), given twice a day in patients with osteoporosis. Preference and acceptability were assessed by means of questionnaires. Preference was determined by asking the question, which treatment the patient preferred, and acceptability was measured by scoring five variables, using rating scales. Of the 102 patients indicating a preference for a trial medication, 67% preferred the chewable tablet, 19% the sachet with calcium and vitamin D3, and 15% stated no preference. The significant preference for Calci Chew D3 (p < 0.0001) was associated with higher scores for all five acceptability variables. The two formulations were tolerated equally well. A significant greater number of patients considered the chewable tablet as preferable and acceptable to the sachet, containing calcium and vitamin D3. Trial registration: Current Controlled Trials ISRCTN18822358