Can Dynamic Compression in the Absence of Growth Factors Induce Chondrogenic Differentiation of Bone Marrow Derived MSCs Encapsulated in Agarose Hydrogels?

The objectives of this study were twofold; to determine if cartilage specific matrix synthesis by mesenchymal stem cells (MSCs) is regulated by the magnitude and/or duration of dynamic compression in the absence of growth factors, and to investigate if expanding MSCs in the presence of both fibroblast growth factor-2 (FGF-2) and transforming growth factor β-3 (TGF-β3) would influence their subsequent response to dynamic compression following encapsulation in agarose hydrogels. Porcine bone marrow derived MSCs were suspended in agarose and cast to produce cylinders (Ø5×3mm). Constructs were maintained in a chemically defined medium. Dynamic compression was applied at 1 Hz at strain amplitudes of 5%, 10% and 5% superimposed upon a 5% pre-strain for durations of 1, 3 and 12 hours. MSCs were also expanded in the presence of FGF-2 and TGF-β3. The biochemical constituents of constructs were analyzed. Under strain magnitudes of 5% and 10% and durations of 1 and 3 hours small increases in sGAG accumulation relative to unloaded controls were observed. However this was orders of magnitude lower than that induced by TGF-β3 stimulation. Expansion in FGF-2 and TGF-β3 did not positively modulate chondrogenesis of MSCs in either unloaded or loaded culture

The TWEAK/Fn14/CD163 axis - Implications for metabolic disease

TWEAK (tumor necrosis factor-like weak inducer of apoptosis) is a member of the TNF superfamily that controls a multitude of cellular events including proliferation, migration, differentiation, apoptosis, angiogenesis, and inflammation. TWEAK control of these events is via an expanding list of intracellular signalling pathways which include NF-κB, ERK/MAPK, Notch, EGFR and AP-1. Two receptors have been identified for TWEAK – Fn14, which targets the membrane bound form of TWEAK, and CD163, which scavenges the soluble form of TWEAK. TWEAK appears to elicit specific events based on the receptor to which it binds, tissue type in which it is expressed, specific extrinsic conditions, and the presence of other cytokines. TWEAK signalling is protective in healthy tissues, but in chronic inflammatory states become detrimental to the tissue. Consistent data show a role for the TWEAK/FN14/CD163 axis in metabolic disease, chronic autoimmune diseases, and acute ischaemic stroke. Low circulating concentrations of soluble TWEAK are predictive of poor cardiovascular outcomes in those with and without diabetes. This review details the current understanding of the TWEAK/Fn14/CD163 axis as one of the chief regulators of immune signalling and its cell-specific role in metabolic disease development and progression

Dynamic compression can inhibit chondrogenesis of mesenchymal stem cells

Funding was provided by Science Foundation Ireland (07-RFP-ENMF142) and Enterprise Ireland (PC/2006/384)

Cell-matrix interactions regulate mesenchymal stem cell response to hydrostatic pressure.

Both hydrostatic pressure (HP) and cell-matrix interactions have independently been shown to regulate the chondrogenic differentiation of mesenchymal stem cells (MSCs). The objective of this study was to test the hypothesis that the response of MSCs to hydrostatic pressure will depend on the biomaterial within which the cells are encapsulated. Bone-marrow-derived MSCs were seeded into either agarose or fibrin hydrogels and exposed to 10 MPa of cyclic HP (1 Hz, 4 h per day, 5 days per week for 3 weeks) in the presence of either 1 or 10 ng ml(-1) of TGF-β3. Agarose hydrogels were found to support a spherical cellular morphology, while MSCs seeded into fibrin hydrogels attached and spread, with clear stress fiber formation. Hydrogel contraction was also observed in MSC-fibrin constructs. While agarose hydrogels better supported chondrogenesis of MSCs, HP only enhanced sulfated glycosaminoglycan (sGAG) accumulation in fibrin hydrogels, which correlated with a reduction in fibrin contraction. HP also reduced alkaline phosphatase activity in the media for both agarose and fibrin constructs, suggesting that this stimulus plays a role in the maintenance of the chondrogenic phenotype. This study demonstrates that a complex relationship exists between cell-matrix interactions and hydrostatic pressure, which plays a key role in regulating the chondrogenic differentiation of MSCs

KAJIAN KEBUTUHAN INTEGRASI LAYANAN ANGKUTAN UMUM MASSAL DI KOTA SEMARANG DAN SEKITARNYA

Angkutan umum massal berbasis jalan telah dikembangkan oleh Pemerintah Kota Semarang sejak tahun 2009 hingga kini (Trans Semarang). Disisi lain, Pemerintah Provinsi Jawa Tengah sejak tahun 2017 juga melakukan hal yang sama di Wilayah Aglomerasi Kedungsepur (Trans Jateng). Namun terkesan berjalan sendiri-sendiri dan terjadi tumpang tindih layanan di ruas-ruas jalan tertentu. Dengan demikian, perlu dilakukan penelitian kebutuhan pengintegrasian layanan angkutan umum massal di Kota Semarang dan sekitarnya. Penelitian ini menggunakan pendekatan kuantitatif dengan analisis statistik deskriptif dan analisis spasial untuk mengetahui karakteristik dan pola permintaan perjalanan penggunanya. Hasil penelitian ini menunjukkan bahwa pengguna Koridor 1 dan 2 Trans Semarang dari luar Kota Semarang mencapai 39,14% dan 60,86% berasal dari dalam Kota Semarang. Pengguna dengan tujuan ke luar Kota Semarang mencapai 42,23% dan 57,77% tujuan di dalam Kota Semarang. Hal ini membuktikan bahwa Koridor 1 dan 2 mengakomodasi penumpang yang asal tujuannya cukup besar dari luar Kota Semarang. Terdapat tumpang tindih layanan mencapai 60% dari panjang lintasan di Koridor 1 Trans Jateng dan Koridor 2 Trans Semarang. Moda first mile pengguna Koridor 2 didominasi oleh Trans Jateng sebesar 51,51% dan last mile didominasi oleh penggunaan motor sebesar 48,10%. Penelitian ini menyarankan bahwa rute layanan Trans Jateng kedepannya dapat mengakomodir permintaan perjalanan di dalam kawasan penyangga dengan konsep layanan loop (mengelilingi), berbeda dari kondisi saat ini. Selanjutnya, layanan Trans Jateng yang menuju ke Kota Semarang dapat berhenti di titik perbatasan, dimana pergerakan kemudian dilayani oleh Trans Semarang dan diharapkan dapat memberikan layanan yang lebih baik kepada masyarakat di Kota Semarang dan sekitarnya.

The effects of dynamic compression on the development of cartilage grafts engineered using bone marrow and infrapatellar fat pad derived stem cells.

Bioreactors that subject cell seeded scaffolds or hydrogels to biophysical stimulation have been used to improve the functionality of tissue engineered cartilage and to explore how such constructs might respond to the application of joint specific mechanical loading. Whether a particular cell type responds appropriately to physiological levels of biophysical stimulation could be considered a key determinant of its suitability for cartilage tissue engineering applications. The objective of this study was to determine the effects of dynamic compression on chondrogenesis of stem cells isolated from different tissue sources. Porcine bone marrow (BM) and infrapatellar fat pad (FP) derived stem cells were encapsulated in agarose hydrogels and cultured in a chondrogenic medium in free swelling (FS) conditions for 21 d, after which samples were subjected to dynamic compression (DC) of 10% strain (1 Hz, 1 h d(-1)) for a further 21 d. Both BM derived stem cells (BMSCs) and FP derived stem cells (FPSCs) were capable of generating cartilaginous tissues with near native levels of sulfated glycosaminoglycan (sGAG) content, although the spatial development of the engineered grafts strongly depended on the stem cell source. The mechanical properties of cartilage grafts generated from both stem cell sources also approached that observed in skeletally immature animals. Depending on the stem cell source and the donor, the application of DC either enhanced or had no significant effect on the functional development of cartilaginous grafts engineered using either BMSCs or FPSCs. BMSC seeded constructs subjected to DC stained less intensely for collagen type I. Furthermore, histological and micro-computed tomography analysis showed mineral deposition within BMSC seeded constructs was suppressed by the application of DC. Therefore, while the application of DC in vitro may only lead to modest improvements in the mechanical functionality of cartilaginous grafts, it may play an important role in the development of phenotypically stable constructs.Funding was provided by the European Research Council Starter Grant (StemRepair—Project number 258463) and a SFI President of Ireland Young Researcher Award (08/Y15/B1336)

European Society of Biomechanics S.M. Perren Award 2012: the external mechanical environment can override the influence of local substrate in determining stem cell fate.

The aim of this study was to explore how cell-matrix interactions and extrinsic mechanical signals interact to determine stem cell fate in response to transforming growth factor-β3 (TGF-β3). Bone marrow derived mesenchymal stem cells (MSCs) were seeded in agarose and fibrin hydrogels and subjected to dynamic compression in the presence of different concentrations of TGF-β3. Markers of chondrogenic, myogenic and endochondral differentiation were assessed. MSCs embedded within agarose hydrogels adopted a spherical cell morphology, while cells directly adhered to the fibrin matrix and took on a spread morphology. Free-swelling agarose constructs stained positively for chondrogenic markers, with MSCs appearing to progress towards terminal differentiation as indicated by mineral staining. MSC seeded fibrin constructs progressed along an alternative myogenic pathway in long-term free-swelling culture. Dynamic compression suppressed differentiation towards any investigated lineage in both fibrin and agarose hydrogels in the short-term. Given that fibrin clots have been shown to support a chondrogenic phenotype in vivo within mechanically loaded joint defect environments, we next explored the influence of long term (42 days) dynamic compression on MSC differentiation. Mechanical signals generated by this extrinsic loading ultimately governed MSC fate, directing MSCs along a chondrogenic pathway as opposed to the default myogenic phenotype supported within unloaded fibrin clots. In conclusion, this study demonstrates that external cues such as the mechanical environment can override the influence specific substrates, scaffolds or hydrogels have on determining mesenchymal stem cell fate. The temporal data presented in this study highlights the importance of considering how MSCs respond to extrinsic mechanical signals in the long term

Determine TB-LAM point-of-care tuberculosis assay predicts poor outcomes in outpatients during their first year of antiretroviral therapy in South Africa.

BACKGROUND: Determine TB-LAM is the first point-of-care test (POC) for HIV-associated tuberculosis (TB) and rapidly identifies TB in those at high-risk for short-term mortality. While the relationship between urine-LAM and mortality has been previously described, the outcomes of those undergoing urine-LAM testing have largely been assessed during short follow-up periods within diagnostic accuracy studies. We therefore sought to assess the relationship between baseline urine-LAM results and subsequent hospitalization and mortality under real-world conditions among outpatients in the first year of ART. METHODS: Consecutive, HIV-positive adults with a CD4 count < 100 cells/uL presenting for ART initiation were enrolled. TB diagnoses and outcomes (hospitalization, loss-to-follow and mortality) were recorded during the first year following enrolment. Baseline urine samples were retrospectively tested using the urine-LAM POC assay. Kaplan Meier survival curves were used to assess the cumulative probability of hospitalization or mortality in the first year of follow-up, according to urine-LAM status. Cox regression analyses were performed to determine independent predictors of hospitalization and mortality at  three months and one year of follow-up. RESULTS: 468 patients with a median CD4 count of 59 cells/uL were enrolled. There were 140 patients (29.9%) with newly diagnosed TB in the first year of follow-up of which 79 (56.4%) were microbiologically-confirmed. A total of 18% (n = 84) required hospital admission and 12.2% (n = 57) died within a year of study entry. 38 out of 468 (8.1%) patients retrospectively tested urine-LAM positive - including 19.0% of those with microbiologically-proven TB diagnoses (n = 15/79) and 23.0% (n = 14/61) of those with clinical-only TB diagnoses; 9 of 38 (23.7%) of patients retrospectively testing LAM positive were never diagnosed with TB under routine program conditions. Among all patients (n = 468) in the first year of follow-up, a positive urine-LAM result was strongly associated with all-cause hospitalization and mortality with a corresponding adjusted hazard ratio (aHR) of 3.7 (95%CI, 1.9-7.1) and 2.6 (95%, 1.2-5.7), respectively. CONCLUSIONS: Systematic urine-LAM testing among ART-naïve HIV-positive outpatients with CD4 counts < 100 cells/uL detected TB cases that were missed under routine programme conditions and was highly predictive for subsequent hospitalization and mortality in the first year of ART

Impacts of air pollution and noise on risk of preterm birth and stillbirth in London

Background Evidence for associations between ambient air pollution and preterm birth and stillbirth is inconsistent. Road traffic produces both air pollutants and noise, but few studies have examined these co-exposures together and none to date with all-cause or cause-specific stillbirths. Objectives To analyse the relationship between long-term exposure to air pollution and noise at address level during pregnancy and risk of preterm birth and stillbirth. Methods The study population comprised 581,774 live and still births in the Greater London area, 2006–2010. Outcomes were preterm birth (<37 completed weeks gestation), all-cause stillbirth and cause-specific stillbirth. Exposures during pregnancy to particulate matter with diameter <2.5 μm (PM2.5) and <10 μm (PM10), ozone (O3), primary traffic air pollutants (nitrogen dioxide, nitrogen oxides, PM2.5 from traffic exhaust and traffic non-exhaust), and road traffic noise were estimated based on maternal address at birth. Results An interquartile range increase in O3 exposure was associated with elevated risk of preterm birth (OR 1.15 95% CI: 1.11, 1.18, for both Trimester 1 and 2), all-cause stillbirth (Trimester 1 OR 1.17 95% CI: 1.07, 1.27; Trimester 2 OR 1.20 95% CI: 1.09, 1.32) and asphyxia-related stillbirth (Trimester 1 OR 1.22 95% CI: 1.01, 1.49). Odds ratios with the other air pollutant exposures examined were null or <1, except for primary traffic non-exhaust related PM2.5, which was associated with 3% increased odds of preterm birth (Trimester 1) and 7% increased odds stillbirth (Trimester 1 and 2) when adjusted for O3. Elevated risk of preterm birth was associated with increasing road traffic noise, but only after adjustment for certain air pollutant exposures. Discussion Our findings suggest that exposure to higher levels of O3 and primary traffic non-exhaust related PM2.5 during pregnancy may increase risk of preterm birth and stillbirth; and a possible relationship between long-term traffic-related noise and risk of preterm birth. These findings extend and strengthen the evidence base for important public health impacts of ambient ozone, particulate matter and noise in early life