Global Deletion of Pannexin 3 Resulting in Accelerated Development of Aging-Induced Osteoarthritis in Mice.

OBJECTIVE: Osteoarthritis (OA) results in pathologic changes in the joint tissue. The mechanisms driving disease progression remain largely unclear, and thus disease-modifying treatments are lacking. Pannexin 3 (Panx3) was identified as a potential mediator of cartilage degeneration in OA, and our previous study in mice indicated that deletion of the Panx3 gene delayed surgically induced cartilage degeneration. This study was undertaken to examine the role of Panx3 in other OA subtypes, particularly primary OA during aging, in a mouse model of aging-induced OA. METHODS: Wild-type (WT) and Panx3-/- C57BL/6J (Black-6) mice, ages 18-24 months, were analyzed by micro-computed tomography to investigate bone mineral density and body composition. Joints were harvested from the mice, and histopathologic analysis of the joint tissue for OA development was conducted with a specific focus on changes in articular cartilage, subchondral bone, and synovial tissue. RESULTS: Global loss of Panx3 in aging mice was not associated with increased mortality or changes in body composition. Mice lacking Panx3 had shorter appendicular skeletons than WT mice, but overall the body compositions appeared quite similar. Panx3 deletion dramatically accelerated cartilage degeneration and subchondral bone thickening with aging in both 18-month-old and 24-month-old mice, while promoting synovitis in 18-month-old mice. CONCLUSION: These observations in a mouse model of OA suggest that Panx3 has a protective role against the development of primary aging-associated OA. It appears that Panx3 has opposing context-specific roles in joint health following traumatic injury versus that associated with aging. These data strongly suggest that there are differences in the molecular pathways driving different subtypes of OA, and therefore a detailed understanding of these pathways could directly improve strategies for OA diagnosis, therapy, and research.

[Ambulatory monitoring and digital phenotyping in the diagnostics and treatment of bipolar disorders]. / Ambulantes Monitoring und digitale Phänotypisierung in Diagnostik und Therapie bipolarer Erkrankungen.

BACKGROUND: Reliable and valid diagnostics and treatment of bipolar disorders and affective episodes are subject to extensive, especially methodological limitations in the clinical practice. OBJECTIVE: The use of smartphones and mobile sensor technology for improvement in diagnostics and treatment of bipolar disorders. METHODS: Critical discussion of current research on the use of ambulatory monitoring and digital phenotyping with bipolar disorders. RESULTS: In many studies the observation periods were too short and the sensors applied were too inaccurate to enable reliable and valid detection of behavioral changes in the context of affective episodes. CONCLUSION: The clarification and operationalization of psychopathological constructs to allow for the measurement of objectively observable and ascertainable behavioral changes during depressive and (hypo)manic states are essential for the successful application of modern mobile technologies in the diagnostics and treatment of bipolar disorders.

Dicam promotes proliferation and maturation of chondrocyte through Indian hedgehog signaling in primary cilia.

OBJECTIVES: Primary cilium is required for mechano-biological signal transduction in chondrocytes, and its interaction with extracellular matrix is critical for cartilage homeostasis. However, the role of cilia-associated proteins that affect the function of cilia remains to be elucidated. Here, we show that Dicam has a novel function as a modulator of primary cilia-mediated Indian hedgehog (Ihh) signaling in chondrocytes. METHODS: Cartilage-specific Dicam transgenic mouse was constructed and the phenotype of growth plates at embryonic day 15.5 and 18.5 was analyzed. Primary chondrocytes and tibiae isolated from embryonic day 15.5 mice were used in vitro study. RESULTS: Dicam was mainly expressed in resting and proliferating chondrocytes of the growth plate and was increased by PTHrP and BMP2 in primary chondrocytes. Cartilage-specific Dicam gain-of-function demonstrated increased length of growth plate in long bones. Dicam enhanced both proliferation and maturation of growth plate chondrocytes in vivo and in vitro, and it was accompanied by enhanced Ihh and PTHrP signaling. Dicam was localized to primary cilia of chondrocytes, and increased the number of primary cilia and their assembly molecule, IFT88/Polaris as well. Dicam successfully rescued the knock-down phenotype of IFT88/Polaris and it was accompanied by increased number of cilia in tibia organ culture. CONCLUSION: These findings suggest that Dicam positively regulates primary cilia and Ihh signaling resulting in elongation of long bone.

Actionable perturbations of damage responses by TCL1/ATM and epigenetic lesions form the basis of T-PLL.

T-cell prolymphocytic leukemia (T-PLL) is a rare and poor-prognostic mature T-cell malignancy. Here we integrated large-scale profiling data of alterations in gene expression, allelic copy number (CN), and nucleotide sequences in 111 well-characterized patients. Besides prominent signatures of T-cell activation and prevalent clonal variants, we also identify novel hot-spots for CN variability, fusion molecules, alternative transcripts, and progression-associated dynamics. The overall lesional spectrum of T-PLL is mainly annotated to axes of DNA damage responses, T-cell receptor/cytokine signaling, and histone modulation. We formulate a multi-dimensional model of T-PLL pathogenesis centered around a unique combination of TCL1 overexpression with damaging ATM aberrations as initiating core lesions. The effects imposed by TCL1 cooperate with compromised ATM toward a leukemogenic phenotype of impaired DNA damage processing. Dysfunctional ATM appears inefficient in alleviating elevated redox burdens and telomere attrition and in evoking a p53-dependent apoptotic response to genotoxic insults. As non-genotoxic strategies, synergistic combinations of p53 reactivators and deacetylase inhibitors reinstate such cell death execution.

Osteoarthritis, cerebrovascular dysfunction and the common denominator of inflammation: a narrative review.

OBJECTIVE: Population-based cohort studies suggest an association between osteoarthritis (OA) and cerebrovascular disease, yet the mechanisms underlying vascular comorbidities in OA remain unclear. The purpose of this narrative review is to discuss the literature examining inflammation in OA with a focus on physiological mechanisms, and whether overlapping mechanisms exist in cerebrovascular dysfunction. METHOD: A literature search was conducted in PubMed using combinations of search terms: osteoarthritis, cerebrovascular (disease/dysfunction/risk), cardiovascular (disease/dysfunction/risk), aging/ageing, inflammation, inflammatory mediators, cytokine, c-reactive protein, interleukin, advanced glycation end-products, metabolic syndrome, reactive oxidative species, cognitive impairment, (vascular-related) dementia, small cerebral vessel disease, endothelial function, blood-brain barrier, gender/sex, hypertension, peripheral vascular health, and physical activity. Reference lists of identified articles were also researched manually. RESULTS: Overlapping inflammatory factors that may contribute to onset and progression of both OA and cerebrovascular dysfunction are presented. We describe oxidative mechanisms involving pro-inflammatory cytokines and oxidative species, advanced glycation end-products, sex hormones, microvascular dysfunction and osteoprotegerin, and their specific roles in potentially contributing to OA and cerebrovascular dysfunction. CONCLUSION: Synthesis of the current literature suggests future investigations may benefit from directly testing cerebrovascular hemodynamics and cognitive function in individuals with or at risk of OA to elucidate common physiological mechanisms.

Single mode 4.3 kW output power from a diode-pumped Yb-doped fiber amplifier.

We investigate the average power scaling of two diode-pumped Yb-doped fiber amplifiers emitting a diffraction-limited beam. The first fiber under investigation with a core diameter of 30 µm was able to amplify a 10 W narrow linewidth seed laser up to 2.8 kW average output power before the onset of transverse mode instabilities (TMI). A further power scaling was achieved using a second fiber with a smaller core size (23µm), which allowed for a narrow linewidth output power of 3.5 kW limited by stimulated Brillouin scattering (SBS). We mitigated SBS using a spectral broadening mechanism, which allowed us to further increase the output power to 4.3 kW only limited by the available pump power. Up to this power level, a high slope efficiency of 90% with diffraction-limited beam quality and without any sign of TMI or stimulated Raman scattering for a spectral dynamic range of higher than -80 dB was obtained.

Whole-body vibration of mice induces articular cartilage degeneration with minimal changes in subchondral bone.

OBJECTIVE: Low-amplitude, high-frequency whole-body vibration (WBV) has been adopted for the treatment of musculoskeletal diseases including osteoarthritis (OA); however, there is limited knowledge of the direct effects of vibration on joint tissues. Our recent studies revealed striking damage to the knee joint following exposure of mice to WBV. The current study examined the effects of WBV on specific compartments of the murine tibiofemoral joint over 8 weeks, including microarchitecture of the tibia, to understand the mechanisms associated with WBV-induced joint damage. DESIGN: Ten-week-old male CD-1 mice were exposed to WBV (45 Hz, 0.3 g peak acceleration; 30 min/day, 5 days/week) for 4 weeks, 8 weeks, or 4 weeks WBV followed by 4 weeks recovery. The knee joint was evaluated histologically for tissue damage. Architecture of the subchondral bone plate, subchondral trabecular bone, primary and secondary spongiosa of the tibia was assessed using micro-CT. RESULTS: Meniscal tears and focal articular cartilage damage were induced by WBV; the extent of damage increased between 4 and 8-week exposures to WBV. WBV did not alter the subchondral bone plate, or trabecular bone of the tibial spongiosa; however, a transient increase was detected in the subchondral trabecular bone volume and density. CONCLUSIONS: The lack of WBV-induced changes in the underlying subchondral bone suggests that damage to the articular cartilage may be secondary to the meniscal injury we detected. Our findings underscore the need for further studies to assess the safety of WBV in the human population to avoid long-term joint damage.

C57BL/6 mice are resistant to joint degeneration induced by whole-body vibration.

OBJECTIVE: Whole-body vibration (WBV) platforms are commercially available devices that are used clinically to treat numerous musculoskeletal conditions based on their reported ability to increase bone mineral density and muscle strength. Despite widespread use, there is an alarming lack of understanding of the direct effects of WBV on joint health. Previous work by our lab demonstrated that repeated exposure to WBV using protocols that model those used clinically, induces intervertebral disc (IVD) degeneration and osteoarthritis-like damage in the knee of skeletally mature, male mice of a single outbred strain (CD-1). The present study examined whether exposure to WBV induces similar deleterious effects in a genetically different strain of mouse (C57BL/6). DESIGN: Male 10-week-old C57BL/6 mice were exposed to vertical sinusoidal WBV for 30 min/day, 5 days/week, for 4 or 8 weeks using previously reported protocols (45 Hz, 0.3 g peak acceleration). Following WBV, joint tissues were examined using histological analysis and gene expression was quantified using real-time PCR (qPCR). RESULTS: Our analyses show a lack of WBV-induced degeneration in either the knee or IVDs of C57BL/6 mice exposed to WBV for 4 or 8 weeks, in direct contrast to the WBV-induced damage previously reported by our lab in CD-1 mice. CONCLUSIONS: Together with previous studies from our group, the present study demonstrates that the effects of WBV on joint tissues vary in a strain-specific manner. These findings highlight the need to examine genetic or physiological differences that may underlie susceptibility to the deleterious effects of WBV on joint tissues.

FOLFIRI plus cetuximab in patients with liver-limited or non-liver-limited RAS wild-type metastatic colorectal cancer: A retrospective subgroup analysis of the CRYSTAL study.

BACKGROUND: Adding cetuximab to first-line FOLFIRI in the phase 3 CRYSTAL trial significantly improved progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) in patients with KRAS wild-type (wt) or RAS wt metastatic colorectal cancer (mCRC). In this retrospective subgroup analysis of CRYSTAL, we investigated benefit of treatment in patients with KRAS wt or RAS wt tumors according to whether patients had liver-limited disease (LLD) or non-LLD, including assessing the role of cetuximab in downsizing metastases and conversion rates from initially unresectable to resectable disease. METHODS: PFS, OS, ORR, and R0 resection rates were analyzed according to treatment arm for the LLD and non-LLD subgroups. RESULTS: Of the 367 patients with RAS wt tumors, 89 (24%) had LLD and 278 (76%) had non-LLD. Within the RAS wt LLD and non-LLD subpopulations, demographic and baseline characteristics were comparable between treatment arms. In patients with RAS wt LLD, adding cetuximab to FOLFIRI significantly improved PFS (hazard ratio [HR][95% CI] = 0.21[0.09-0.49]) and ORR (odds ratio [OR][95% CI] = 8.99[3.17-25.52]), and numerically improved OS (HR[95% CI] = 0.65[0.38-1.10]) and R0 resection rate (OR[95% CI] = 2.68[0.63-11.43]) relative to FOLFIRI alone. In patients with RAS wt non-LLD, adding cetuximab to FOLFIRI significantly improved PFS (HR[95% CI] = 0.65[0.46-0.93]), OS (HR[95% CI] = 0.71[0.54-0.93]), ORR (OR[95% CI] = 2.44[1.49-3.98]), and-numerically-R0 resection rate (OR[95% CI] = 5.94[0.79-44.88]). Similar results were obtained from the KRAS wt population. CONCLUSIONS: Adding cetuximab to first-line FOLFIRI appears to improve clinical outcomes and R0 resection rates in KRAS wt and RAS wt mCRC patients with LLD as well as in those with non-LLD.

Narrow linewidth, single mode 3 kW average power from a directly diode pumped ytterbium-doped low NA fiber amplifier.

We report on a newly designed and fabricated ytterbium-doped large mode area fiber with an extremely low NA (~0.04) and related systematic investigations on fiber parameters that crucially influence the mode instability threshold. The fiber is used to demonstrate a narrow linewidth, continuous wave, single mode fiber laser amplifier emitting a maximum output power of 3 kW at a wavelength of 1070 nm without reaching the mode-instability threshold. A high slope efficiency of 90 %, excellent beam quality, high temporal stability, and an ASE suppression of 70 dB could be reached with a signal linewidth of only 170 pm.

FOLFOX4 plus cetuximab treatment and RAS mutations in colorectal cancer.

BACKGROUND: The OPUS study demonstrated that addition of cetuximab to 5-fluorouracil, folinic acid and oxaliplatin (FOLFOX4) significantly improved objective response and progression-free survival (PFS) in the first-line treatment of patients with KRAS exon 2 wild-type metastatic colorectal cancer (mCRC). In patients with KRAS exon 2 mutations, a detrimental effect was seen upon addition of cetuximab to FOLFOX4. The current study reports outcomes in subgroups defined by extended RAS testing. PATIENTS AND METHODS: Samples from OPUS study KRAS exon 2 wild-type tumours were reanalysed for other RAS mutations in four additional KRAS codons (exons 3-4) and six NRAS codons (exons 2-4) using BEAMing. A cutoff of ⩾5% mutant/wild-type sequences was selected to define RAS status; we also report an analysis using a cutoff based on the technical lower limit for mutation identification (0.1%). RESULTS: Other RAS mutations were detected in 31/118 (26%) evaluable patients. In the extended analysis of RAS wild-type tumours (n=87), objective response was significantly improved by addition of cetuximab to FOLFOX4 (58% versus 29%; odds ratio 3.33 [95% confidence interval 1.36-8.17]; P=0.0084); although limited by population size, there also appeared to be trends favouring the cetuximab arm in terms of PFS and overall survival in the RAS wild-type group compared with the RAS evaluable group. There was no evidence that patients with other RAS mutations benefited from cetuximab, but small numbers precluded precise estimations of treatment effects. In the combined population of patients with any RAS mutation (KRAS exon 2 or other RAS), a clear detrimental effect was associated with addition of cetuximab to FOLFOX4. CONCLUSION: Patients with RAS-mutant mCRC, as defined by mutations in KRAS and NRAS exons 2-4, derive no benefit and may be harmed by the addition of cetuximab to FOLFOX4. Restricting cetuximab administration to patients with RAS wild-type tumours will further tailor therapy to maximise benefit.

Weight-bearing asymmetry and vertical activity differences in a rat model of post-traumatic knee osteoarthritis.

OBJECTIVE: This study used a rat model of post-traumatic knee osteoarthritis (OA) created by anterior cruciate ligament transection with partial medial meniscectomy (ACLT + pMMx). In this model, mild to moderate structural changes that are typical of knee OA have been observed within 2 and 8 weeks post-surgery. We aimed to determine whether pain-related behaviours can distinguish between an ACLT + pMMx and a sham surgery group. DESIGN: Three-month old male Sprague-Dawley rats underwent ACLT + pMMx on their right hindlimb within two groups of n = 6 each, and sham surgery within two groups of n = 5 each. Assessments evaluated percent ipsilateral weight-bearing for static weight-bearing and 18 different variables of exploratory motor behaviour at multiple time points between 1 and 8 weeks post-surgery. Histology was performed on the right hindlimbs at 4 and 8 weeks post-surgery. RESULTS: Histology confirmed mild to moderate knee OA changes in the ACLT + pMMx group and the absence of knee OA changes in the sham group. Compared to the sham group, the ACLT + pMMx group had significantly lower percent ipsilateral weight-bearing from 1 through 8 weeks post-surgery. Compared to the sham group, the ACLT + pMMx group had significantly lower vertical activity (episode count, time, and count) values. CONCLUSIONS: These findings suggest that ipsilateral weight-bearing deficit and vertical activity limitations resulted from the presence of knee OA-like changes in this model. When using the ACLT + pMMx-induced rat model of knee OA, percent ipsilateral weight-bearing and vertical activity distinguished between rats with and without knee OA changes. These variables may be useful outcome measures in preclinical research performed with this experimental post-traumatic knee OA model.

CXC chemokine ligand 12a enhances chondrocyte proliferation and maturation during endochondral bone formation.

OBJECTIVE: We investigated the roles of CXC chemokine ligand 12a (CXCL12a), also known as stromal cell-derived factor-1α (SDF-1α), in endochondral bone growth, which can give us important clues to understand the role of CXCL12a in osteoarthritis (OA). METHODS: Primary chondrocytes and tibial explants from embryonic 15.5 day-old mice were cultured with recombinant mouse CXCL12a. To assess the role of CXCL12a in chondrogenic differentiation, we conducted mesenchymal cell micromass culture. RESULTS: In tibia organ cultures, CXCL12a increased total bone length in a dose-dependent manner through proportional effects on cartilage and bone. In accordance with increased length, CXCL12a increased the protein level of proliferation markers, such as cyclin D1 and proliferating cell nuclear antigen (PCNA), in primary chondrocytes as well as in tibia organ culture. In addition, CXCL12a increased the expression of Runx2, Col10 and MMP13 in primary chondrocytes and tibia organ culture system, implying a role of CXCL12a in chondrocyte maturation. Micromass cultures of limb-bud mesenchymal progenitor cells (MPCs) revealed that CXCL12a has a limited effect on early chondrogenesis, but significantly promoted maturation of chondrocytes. CXCL12a induced the phosphorylation of p38 and Erk1/2 MAP kinases and IκB. The increased expression of cyclin D1 by CXCL12a was significantly attenuated by inhibitors of MEK1 and NF-κB. On the other hand, p38 and Erk1/2 MAP kinase and NF-κB signaling were associated with CXCL12a-induced expression of Runx2 and MMP13, the marker of chondrocyte maturation. CONCLUSION: CXCL12a promoted the proliferation and maturation of chondrocytes, which strongly suggest that CXCL12a may have a negative effect on articular cartilage and contribute to OA progression.

Peroxisome proliferator-activated receptor δ promotes the progression of posttraumatic osteoarthritis in a mouse model.

OBJECTIVE: Osteoarthritis (OA) is a serious disease of the entire joint, characterized by articular cartilage degeneration, subchondral bone changes, osteophyte formation, and synovial hyperplasia. Currently, there are no pharmaceutical treatments that can slow the disease progression, resulting in greatly reduced quality of life for patients and the need for joint replacement surgeries in many cases. The lack of available treatments for OA is partly due to our incomplete understanding of the molecular mechanisms that promote disease initiation and progression. The purpose of the present study was to examine the role of the nuclear receptor peroxisome proliferator-activated receptor δ (PPARδ) as a promoter of cartilage degeneration in a mouse model of posttraumatic OA. METHODS: Mouse chondrocytes and knee explants were treated with a pharmacologic agonist of PPARδ (GW501516) to evaluate changes in gene expression, histologic features, and matrix glycosaminoglycan breakdown. In vivo, PPARδ was specifically deleted from the cartilage of mice. Histopathologic scoring according to the Osteoarthritis Research Society International (OARSI) system and immunohistochemical analysis were used to compare mutant and control mice subjected to surgical destabilization of the medial meniscus (DMM). RESULTS: In vitro, PPARδ activation by GW501516 resulted in increased expression of several proteases in chondrocytes, as well as aggrecan degradation and glycosaminoglycan release in knee joint explants. In vivo, cartilage-specific PPARδ-knockout mice did not display any abnormalities of skeletal development but showed marked protection in the DMM model of posttraumatic OA (as compared to control littermates). OARSI scoring and immunohistochemical analyses confirmed strong protection of mutant mice from DMM-induced cartilage degeneration. CONCLUSION: These data demonstrate a catabolic role of endogenous PPARδ in posttraumatic OA and suggest that pharmacologic inhibition of PPARδ is a promising therapeutic strategy.

Osteoarthritis year in review 2014: mechanics--basic and clinical studies in osteoarthritis.

The purpose of this review was to highlight recent research in mechanics and osteoarthritis (OA) by summarizing results from selected studies spanning basic and clinical research methods. Databases were searched from January 2013 through to March 2014. Working in pairs, reviewers selected 67 studies categorized into four themes--mechanobiology, ambulatory mechanics, biomechanical interventions and mechanical risk factors. Novel developments in mechanobiology included the identification of cell signaling pathways that mediated cellular responses to loading of articular cartilage. Studies in ambulatory mechanics included an increased focus on instrumented knee implants and progress in computational models, both emphasizing the importance of muscular contributions to load. Several proposed biomechanical interventions (e.g., shoe insoles and knee braces) produced variable changes in external knee joint moments during walking, while meta-analysis of randomized clinical trials did not support the use of lateral wedge insoles for decreasing pain. Results from high quality randomized trials suggested diet with or without exercise decreased indicators of knee joint load during walking, whereas similar effects from exercise alone were not detected with the measures used. Data from longitudinal cohorts suggested mechanical alignment was a risk factor for incidence and progression of OA, with the mechanism involving damage to the meniscus. In combination, the basic and clinical studies highlight the importance of considering multiple contributors to joint loading that can evoke both protective and damaging responses. Although challenges clearly exist, future studies should strive to integrate basic and clinical research methods to gain a greater understanding of the interactions among mechanical factors in OA and to develop improved preventive and therapeutic strategies.

1009 nm continuous-wave ytterbium-doped fiber amplifier emitting 146 W.

In this Letter, we demonstrate a single-mode continuous-wave fiber laser amplifier emitting 146 W of average output power at a wavelength of 1009 nm. The wavelength and bandwidth of the seed oscillator are defined by a pair of fiber Bragg gratings. The seed is amplified in a two-stage ytterbium-doped rod-type amplifier to 146 W with a high slope efficiency of 64%, showing excellent beam quality and stability throughout the experiment. The ASE suppression is as high as 63 dB.