ERα signaling regulates MMP3 expression to induce FasL cleavage and osteoclast apoptosis

The benefits of estrogens on bone health are well established; how estrogens signal to regulate bone formation and resorption is less well understood. We show here that 17β‐estradiol (E2)‐induced apoptosis of bone‐resorbing osteoclasts is mediated by cleavage and solubilization of osteoblast‐expressed Fas ligand (FasL). U2OS‐ERα osteoblast‐like cells expressing an EGFP‐tagged FasL at the C‐terminus showed decreased fluorescence after E2 treatment, indicative of a cleavage event. Treatment of U2OS‐ERα cultures with a specific MMP3 inhibitor in the presence of E2 blocked FasL cleavage and showed an increase in the number of EGFP‐FasL⁺ cells. siRNA experiments successfully knocked down MMP3 expression and restored full‐length FasL to basal levels. E2 treatment of both human and murine primary osteoblasts showed upregulation of MMP3 mRNA expression, and calvarial organ cultures showed increased expression of MMP3 protein and colocalization with the osteoblast‐specific RUNX2 after E2 treatment. In addition, osteoblast cell cultures derived from ERαKO mice showed decreased expression of MMP3 but not MMP7 and ADAM10, two known FasL proteases, demonstrating that ERα signaling regulates MMP3. Also, conditioned media of E2‐treated calvarial osteoblasts showed an approximate sixfold increase in the concentration of soluble FasL, indicating extensive cleavage, and soluble FasL concentrations were reduced in the presence of a specific MMP3 inhibitor. Finally, to show the role of soluble FasL in osteoclast apoptosis, human osteoclasts were cocultured with MC3T3 osteoblasts. Both a specific MMP3 inhibitor and an MMP inhibitor cocktail preserved osteoclast differentiation and survival in the presence of E2 and demonstrate the necessity of MMP3 for E2‐induced osteoclast apoptosis. These experiments further define the molecular mechanism of estrogen's bone‐protective effects by inducing osteoclast apoptosis through upregulation of MMP3 and FasL cleavage. © 2013 American Society for Bone and Mineral Research     

Activity of the Na,K-ATPase α4 Isoform Is Regulated During Sperm Capacitation to Support Sperm Motility

The α4 polypeptide is a testis-specific isoform of the catalytic subunit of the Na,K-ATPase, which is essential for sperm motility and fertility. In the present study, we have investigated the regulation of activity of the α4 isoform and the relevance of this event for sperm capacitation. We have performed this by taking advantage of the selective high affinity of α4 for the inhibitor ouabain. Our results show that ouabain-sensitive hydrolysis of ATP and uptake of (86)Rb, corresponding to the enzymatic and ion transport activities of α4, respectively, increased during sperm capacitation in a time-dependent manner. Specific labeling of α4 with the fluorescent indicator bodipy-ouabain and immunoblot analysis of biotinylated and streptavidin-precipitated sperm plasma membrane proteins indicated a capacitation- and time-dependent rise in levels of active α4 isoform at the sperm surface. Ouabain inhibition of α4 blocked the increase in total sperm motility and the hyperactive motility pattern characteristic of sperm capacitation. Moreover, interference of α4 activity with ouabain partially prevented the intracellular decrease in Na(+) and the plasma membrane hyperpolarization that typically accompany sperm capacitation. In contrast, ouabain inhibition of α4 did not affect the spontaneous sperm acrosomal reaction following capacitation. Together, these results demonstrate that Na,K-ATPase α4 activity is up-regulated during sperm capacitation through mechanisms that involve both increases in molecular activity and levels of α4 at the sperm plasma membrane. This increase in α4 activity helps maintain the changes in motility that are associated with sperm capacitation, emphasizing the biologic relevance of the Na,K-ATPase α4 isoform in sustaining sperm function.     

Vinyl glove ingestion in children: a word of caution

BackgroundVinyl gloves when ingested will harden and develop sharp edges producing gastric bezoars; bowel obstruction; and, ultimately, perforation. We report 4 children with complications secondary to vinyl glove ingestion who required surgical intervention.MethodsA 3-year-old boy, a 13-year-old adolescent girl with Down syndrome, a 14-year-old adolescent girl, and a 15-year-old adolescent boy presented with bowel obstruction secondary to a bezoar caused by a vinyl glove. The adolescent girl with Down syndrome presented again at age 17 years with a large vinyl glove gastric bezoar. Three of the children had mental retardation, and 1 was a victim of child abuse. Three had laparoscopic-assisted removal of the vinyl glove bezoar, and 1 had laparotomy.ResultsThe 4 children recovered uneventfully. Two of the patients had unsuspected intestinal perforation. The caretakers denied awareness of the vinyl glove ingestion.ConclusionsVinyl glove ingestion can cause intestinal obstruction and perforation. Vinyl gloves should be removed from the immediate proximity of mentally retarded patients or patients with pica. Most of the time, the finding of vinyl gloves as etiology of the obstruction or perforation is incidental. If the event is known or witnessed, prompt surgical intervention is generally recommended.     

Analysis of 185 iliac vessel injuries: risk factors and predictors of outcome

HYPOTHESIS: Iliac vascular injuries incur high mortality. DESIGN: Retrospective 100-month study (January 1, 1992, through April 30, 2000). PATIENTS: One hundred forty-eight patients with 185 iliac vessel injuries. OUTCOME MEASURES: Survival and mortality, analyzed by univariate and logistic regression. RESULTS: Admission mean +/- SD systolic blood pressure was 81 +/- 42 mm Hg, mean Revised Trauma Score was 6.0 +/- 2.8, and mean Injury Severity Score was 20.0 +/- 9.5. The mechanism of injury was penetrating in 140 patients (95%) and blunt in 8 (5%). The mean estimated blood loss was 6246 +/- 6174 mL. Of the 185 injured vessels, 71 (99%) of 72 iliac arteries were repaired, 101 (89%) of 113 iliac veins were ligated, and 12 (11%) of 113 iliac veins were repaired. Overall survival was 51% (76/148). Mortality was 82% (49/72) in patients with exsanguination. Survival by vessel: iliac artery, 57% (20/35); iliac vein, 55% (42/76); and iliac artery and vein, 38% (14/37). Significant predictors of outcome were thoracotomy in the emergency department, associated aortic injury, inferior vena cava injuries, iliac artery and vein injury, intraoperative arrhythmia, and intraoperative coagulopathy. On logistic regression, independent risk factors for survival were absence of thoracotomy in the emergency department, surgical management, and arrhythmia. Mortality by grade on the Organ Injury Scale of the American Association for the Surgery of Trauma (AAST-OIS) was as follows: grade III, 35% (33/95); grade IV, 71% (24/34); and grade V, 79% (15/19). CONCLUSIONS: Mortality remains high. Associated vessel injuries and intraoperative complications predict mortality. AAST-OIS grade for abdominal vascular injuries correlates well with mortality.     

Laparoscopic placement of peritoneal dialysis catheters in children

Background

Peritoneal dialysis (PD) is preferred over hemodialysis. The aim of this study was to evaluate our experience with laparoscopic PD catheter placement and omentectomy in children.

Methods

We reviewed all children (N = 21) who underwent laparoscopic placement of PD catheters and omentectomy. Ages ranged from 3 months to 16 years. Five children had previous major abdominal surgery and required extensive lysis of adhesions. During the same intervention, other surgical procedures were performed using laparoscopy or open technique, including umbilical hernia repair in 3, bilateral inguinal hernia repair in 3, ventral hernia repair in 2, gastrostomy in 4, kidney biopsy in 2, and cholecystectomy in 1.

Results

Thirteen children received successful kidney transplantation and no longer needed dialysis. Two children still have functioning PD catheters. One patient developed membrane failure and was converted to hemodialysis. Four patients recovered enough renal function and no longer need dialysis. There were no complications related to the laparoscopic procedure.

Conclusion

Laparoscopy is ideal for PD catheter placement. It facilitates omentectomy, and it allows for the catheter to be placed in the proper position under direct vision and for lysis of adhesions to increase peritoneal surface. Other abdominal procedures can be performed laparoscopically at the same time.     

Preservation of Muscular and Elastic Artery Distensibility After an Intercontinental Cryoconserved Exchange: Theoretical Advances in Arterial Homograft Generation and Utilization

While the situation of tissue donation and transplantation differs between Latin American and European countries, a common problem is tissue deficiency. Hence, at present, there is a pressing need to generate alternatives so as to increase the possibilities of obtaining the requested materials. Consequently, it would be of significant interest to establish an intercontinental network for tissue exchange, to improve international cooperation, and to help patients that need tissue transplantation, and to evaluate the feasibility of using an intercontinental network for the exchange of cryopreserved arteries (cryografts), preserving the arterial distensibility and ensuring a reduced native artery–cryograft biomechanical mismatch. Distensibility was studied in ovine arteries divided into three groups: intact (in vivo tests, conscious animals), fresh control (in vitro tests immediately after the artery excision, Uruguay), and cryografts (in vitro tests of cryopreserved-transported-defrosted arteries, Spain). Histological studies were performed so as to analyze changes in the endothelial layer and elastic components. The comparison between fresh control and cryografts showed that neither the cryopreservation nor the exchange network impaired the distensibility, despite the expected histological changes found in the cryografts. The comparison between intact and cryografts showed that the cryografts would be capable of ensuring a reduced biomechanical mismatch. The cryopreservation and the intercontinental network designed for artery exchange preserved the arterial distensibility. It could be possible to transfer cryografts between Latin America and Europe to be used in cardiovascular surgeries and/or for tissue banking reprocessing, with basic biomechanical properties similar to those of the fresh and/or native arteries.     

Reference charts for the relationships between dual-energy X-ray absorptiometry-assessed bone mineral content and lean mass in 3,063 healthy men and premenopausal and postmenopausal women

Correlations between dual-energy X-ray absorptiometry (DXA)-assessed bone mineral content and lean mass (BMC-LM curves), and between BMC/LM ratio and age ([BMC/LM]–age curves), were analyzed in the whole body (WB), the upper limbs (ULs) and the lower limbs (LLs) of 3,063 healthy Hispanic adults. Groups of 472 men aged 25–87years, 1,035 premenopausal (pre-MP) women aged 27–54 years, and 1,556 post-menopausal (post-MP) women aged 48–93 years were studied with a GE-Lunar DPX-Plus device. BMC-LM curves confirmed previous observations that BMC and LM masses always correlate linearly, with similar slopes within each region, but differing in intercepts according to gender and hormonal status. Multiple regression tests showed little or no independent interaction of body weight or height with those relationships. [BMC/LM]–age curves were flat in men but showed the positive influence of estrogens throughout the age range in women. Z-scored graphs of all the corresponding relationships were compiled, showing the confidence intervals for means ±1, ±2, and ±3 SDs of the data (±1, ±2, ±3 z-scores) along BMC-LM and [BMC/LM]–age curves. These charts are proposed as references for assessing how well bone mass (as assessed by BMC) and muscle mass (assumed proportional to LM) follow the natural anthropometric/biomechanical proportionality in Hispanic men and women within the age range studied, employing similar devices. Charts for LLs, showing the lowest variance amongst the studied correlations and approaching the origin as an exclusive feature, could provide the most accurate reference curves. Differences between data from ULs and LLs may provide information about any eventual interaction of body-weight bearing with the general results. The proposed analysis may provide useful information for approaching a differential diagnosis between disuse-related and other types of osteopenias employing only DXA.