Reducing Complications in Pilon Fracture Surgery: Surgical Time Matters.

OBJECTIVE: To correlate patient-specific and surgeon-specific factors with outcomes after operative management of distal intra-articular tibia fractures. DESIGN: Retrospective cohort study. SETTING: 3 Level 1 tertiary academic trauma centers. PATIENTS/PARTICIPANTS: The study included a consecutive series of 175 patients with OTA/AO 43-C pilon fractures. MAIN OUTCOME MEASUREMENTS: Primary outcomes included superficial and deep infection. Secondary outcomes included nonunion, loss of articular reduction, and implant removal. RESULTS: The following patient-specific factors correlated with poor surgical outcomes: increased age with superficial infection rate ( P < 0.05), smoking with rate of nonunion ( P < 0.05), and Charlson Comorbidity Index with loss of articular reduction ( P < 0.05). Each additional 10 minutes of operative time over 120 minutes was associated with increased odds of requiring I&D and any treatment for infection. The same linear effect was seen with the addition of each fibular plate. The number of approaches, type of approach, use of bone graft, and staging were not associated with infection outcomes. Each additional 10 minutes of operative time over 120 minutes was associated with an increased rate of implant removal, as did fibular plating. CONCLUSIONS: While many of the patient-specific factors that negatively affect surgical outcomes for pilon fractures may not be modifiable, surgeon-specific factors need to be carefully examined because these may be addressed. Pilon fracture fixation has evolved to increasingly use fragment-specific approaches applied with a staged approach. Although the number and type of approaches did not affect outcomes, longer operative time was associated with increased odds of infection, while additional fibular plate fixation was associated with higher odds of both infection and implant removal. Potential benefits of additional fixation should be weighed against operative time and associated risk of complications. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Is Psychiatric Illness Associated With Worse Outcomes Following Pilon Fracture?

Background: Patients with psychiatric comorbidities represent a significant subset of those sustaining pilon fractures. The purpose of this study is to examine the association of psychiatric comorbidities (PC) in patients with pilon fractures and clinical outcomes. Methods: A multi-institution, retrospective review was conducted. Inclusion/exclusion criteria were skeletally mature patients with a tibia pilon fracture (OTA Type 43B/C) who underwent definitive fracture fixation utilizing open reduction internal fixation (ORIF) with a minimum of 24 weeks of follow-up. Patients were stratified into two groups for comparison: PC group and no PC group. Results: There were 103 patients with pilon fractures that met the inclusion/exclusion criteria of this study. Of these patients, 22 (21.4%) had at least one psychiatric comorbidity (PC) and 81 (78.6%) did not have psychiatric comorbidities (no PC). There was a higher percentage of female patients (PC: 59.1% vs no PC: 25.9%, p=0.0.005), smokers (PC: 40.9% vs no PC: 16.0%, p=0.02), and drug users (PC: 22.7% vs no PC: 8.6%, p=0.08) amongst PC patients. Fracture comminution (PC: 54.5% vs no PC: 32.1%, p=0.05) occurred more frequently in PC patients. The PC group had a higher incidence of weightbearing noncompliance (22.7% vs 7.5%, p=0.04) and reoperation (PC: 54.5% vs no PC: 29.6%, p=0.03). Conclusion: Patients with psychiatric comorbidities represent a significant percentage of pilon fracture patients and appear to be at higher risk for postoperative complication. Risk factors that may predispose patients in the PC group include smoking/substance use, weightbearing noncompliance, and fracture comminution. Level of Evidence: III.

Diagnostic Arthroscopy of the Minipig Stifle (Knee) for Translational Large Animal Research.

To gain regulatory approval for the clinical use of knee biologics and devices in humans, translational large-animal studies are typically required. Animal models that permit second-look arthroscopy are valuable because they allow for longitudinal assessment of the treated tissue without needing to sacrifice the animal. The minipig is an ideal preclinical animal model for the investigation of therapies for the knee, in part because arthroscopy can be performed in its stifle (knee) joint with the use of standard surgical equipment used in humans. The purpose of this Technical Note is to describe a reproducible technique for diagnostic arthroscopy of the minipig stifle (knee) joint.

Combined effects of bone morphogenetic protein 10 and crossveinless-2 on cardiomyocyte differentiation in mouse adipocyte-derived stem cells.

Bone morphogenetic protein (BMP) 10, a cardiac-restricted BMP family member, is essential in cardiomyogenesis, especially during trabeculation. Crossveinless-2 (CV2, also known as BMP endothelial cell precursor derived regulator [BMPER]) is a BMP-binding protein that modulates the activity of several BMPs. The objective of this study was to examine the combined effects of BMP10 and CV2 on cardiomyocyte differentiation using mouse dedifferentiated fat (mDFAT) cells, which spontaneously differentiate into cardiomyocyte-like cells, as a model. Our results revealed that CV2 binds directly to BMP10, as determined by co-immunoprecipitation, and inhibits BMP10 from initiating SMAD signaling, as determined by luciferase reporter gene assays. BMP10 treatment induced mDFAT cell proliferation, whereas CV2 modulated the BMP10-induced proliferation. Differentiation of cardiomyocyte-like cells proceeded in a reproducible fashion in mDFAT cells, starting with small round Nkx2.5-positive progenitor cells that progressively formed myotubes of increasing length that assembled into beating colonies and stained strongly for Troponin I and sarcomeric alpha-actinin. BMP10 enhanced proliferation of the small progenitor cells, thereby securing sufficient numbers to support formation of myotubes. CV2, on the other hand, enhanced formation and maturation of large myotubes and myotube-colonies and was expressed by endothelial-like cells in the mDFAT cultures. Thus BMP10 and CV2 have important roles in coordinating cardiomyogenesis in progenitor cells.

Pluripotent stem cells derived from mouse and human white mature adipocytes.

White mature adipocytes give rise to so-called dedifferentiated fat (DFAT) cells that spontaneously undergo multilineage differentiation. In this study, we defined stem cell characteristics of DFAT cells as they are generated from adipocytes and the relationship between these characteristics and lineage differentiation. Both mouse and human DFAT cells, prepared from adipose tissue and lipoaspirate, respectively, showed evidence of pluripotency, with a maximum 5-7 days after adipocyte isolation. The DFAT cells spontaneously formed clusters in culture, which transiently expressed multiple stem cell markers, including stage-specific embryonic antigens, and Sca-1 (mouse) and CD105 (human), as determined by real-time polymerase chain reaction, fluorescence-activated cell sorting, and immunostaining. As the stem cell markers decreased, markers characteristic of the three germ layers and specific lineage differentiation, such as α-fetoprotein (endoderm, hepatic), Neurofilament-66 (ectoderm, neurogenic), and Troponin I (mesoderm, cardiomyogenic), increased. However, no teratoma formation was detected after injection in immunodeficient mice. A novel modification of the adipocyte isolation aimed at ensuring the initial purity of the adipocytes and avoiding ceiling culture allowed isolation of DFAT cells with pluripotent characteristics. Thus, the adipocyte-derived DFAT cells represent a plastic stem cell population that is highly responsive to changes in culture conditions and may benefit cell-based therapies.

miRNA-302b suppresses human hepatocellular carcinoma by targeting AKT2.

UNLABELLED: miRNAs (miR) play a critical role in human cancers, including hepatocellular carcinoma. Although miR-302b has been suggested to function as a tumor repressor in other cancers, its role in hepatocellular carcinoma is unknown. This study investigated the expression and functional role of miR-302b in human hepatocellular carcinoma. The expression level of miR-302b is dramatically decreased in clinical hepatocellular carcinoma specimens, as compared with their respective nonneoplastic counterparts, and in hepatocellular carcinoma cell lines. Overexpression of miR-302b suppressed hepatocellular carcinoma cell proliferation and G1-S transition in vitro, whereas inhibition of miR-302b promoted hepatocellular carcinoma cell proliferation and G1-S transition. Using a luciferase reporter assay, AKT2 was determined to be a direct target of miR-302b. Subsequent investigation revealed that miR-302b expression was inversely correlated with AKT2 expression in hepatocellular carcinoma tissue samples. Importantly, silencing AKT2 recapitulated the cellular and molecular effects seen upon miR-302b overexpression, which included inhibiting hepatocellular carcinoma cell proliferation, suppressing G1 regulators (Cyclin A, Cyclin D1, CDK2) and increasing p27Kip1 phosphorylation at Ser10. Restoration of AKT2 counteracted the effects of miR-302b expression. Moreover, miR-302b was able to repress tumor growth of hepatocellular carcinoma cells in vivo. IMPLICATIONS: Taken together, miR-302b inhibits HCC cell proliferation and growth in vitro and in vivo by targeting AKT2.

A role for the endothelium in vascular calcification.

RATIONALE: Vascular calcification is a regulated process that involves osteoprogenitor cells and frequently complicates common vascular disease, such as atherosclerosis and diabetic vasculopathy. However, it is not clear whether the vascular endothelium has a role in contributing osteoprogenitor cells to the calcific lesions. OBJECTIVE: To determine whether the vascular endothelium contributes osteoprogenitor cells to vascular calcification. METHODS AND RESULTS: In this study, we use 2 mouse models of vascular calcification, mice with gene deletion of matrix Gla protein, a bone morphogenetic protein (BMP)-inhibitor, and Ins2Akita/+ mice, a diabetes model. We show that enhanced BMP signaling in both types of mice stimulates the vascular endothelium to contribute osteoprogenitor cells to the vascular calcification. The enhanced BMP signaling results in endothelial-mesenchymal transitions and the emergence of multipotent cells, followed by osteoinduction. Endothelial markers colocalize with multipotent and osteogenic markers in calcified arteries by immunostaining and fluorescence-activated cell sorting. Lineage tracing using Tie2-Gfp transgenic mice supports an endothelial origin of the osteogenic cells. Enhancement of matrix Gla protein expression in Ins2Akita/+ mice, as mediated by an Mgp transgene, limits the generation of multipotent cells. Moreover, matrix Gla protein-depleted human aortic endothelial cells in vitro acquire multipotency rendering the cells susceptible to osteoinduction by BMP and high glucose. CONCLUSIONS: Our data suggest that the endothelium is a source of osteoprogenitor cells in vascular calcification that occurs in disorders with high BMP activation, such as deficiency of BMP-inhibitors and diabetes mellitus.