Pulsed electromagnetic fields promote repair of focal articular cartilage defects with engineered osteochondral constructs

Articular cartilage injuries are a common source of joint pain and dysfunction. We hypothesized that pulsed electromagnetic fields (PEMFs) would improve growth and healing of tissue-engineered cartilage grafts in a direction-dependent manner. PEMF stimulation of engineered cartilage constructs was first evaluated in vitro using passaged adult canine chondrocytes embedded in an agarose hydrogel scaffold. PEMF coils oriented parallel to the articular surface induced superior repair stiffness compared to both perpendicular PEMF (p = .026) and control (p = .012). This was correlated with increased glycosaminoglycan deposition in both parallel and perpendicular PEMF orientations compared to control (p = .010 and .028, respectively). Following in vitro optimization, the potential clinical translation of PEMF was evaluated in a preliminary in vivo preclinical adult canine model. Engineered osteochondral constructs (∅ 6 mm × 6 mm thick, devitalized bone base) were cultured to maturity and implanted into focal defects created in the stifle (knee) joint. To assess expedited early repair, animals were assessed after a 3-month recovery period, with microfracture repairs serving as an additional clinical control. In vivo, PEMF led to a greater likelihood of normal chondrocyte (odds ratio [OR]: 2.5, p = .051) and proteoglycan (OR: 5.0, p = .013) histological scores in engineered constructs. Interestingly, engineered constructs outperformed microfracture in clinical scoring, regardless of PEMF treatment (p < .05). Overall, the studies provided evidence that PEMF stimulation enhanced engineered cartilage growth and repair, demonstrating a potential low-cost, low-risk, noninvasive treatment modality for expediting early cartilage repair.     

DNA sequences at the sites of three insertions of the transposable element Tn5 in the histidine operon of Salmonella

Summary The DNA sequence has been determined at the sites of three independent occurrences of the transposable element Tn5 in the hisG gene of the histidine operon. All three insertion sites are adjacent to G+C-rich stretches of DNA. In all three cases sequences at the sites of insertion show homology with a region near the ends of Tn5.     

Leishmania infantum: mixed T-helper-1/T-helper-2 immune response in experimentally infected BALB/c mice

The main goal of the present study was to characterise the course of infection and immunological responses developed by Leishmania infantum infected BALB/c mice. Parasite load was determined by Real-time TaqMan PCR while cytokine and Immunoglobulin G (IgG) production were assessed by ELISA. Leishmania DNA was detected in spleen and liver as soon as day 1 post-inoculation (pi) and the parasitism was sustained until the end of the experiment. The cytokine kinetics in spleen and liver was generally associated with the oscillations of parasite load. Overall, it was not observed a distinct Th1 or Th2 pattern of cytokine production during the time of experiment. The infected mice developed a mixed immune response, with concomitant production of IFN-gamma, IL-4 and IL-10, both in spleen and liver, and both IgG isotypes. However, our results suggest that, compared to liver, the spleen is more susceptible to L. infantum infection.     

Fibromyalgia Patients Had Normal Distraction Related Pain Inhibition but Cognitive Impairment Reflected in Caudate Nucleus and Hippocampus during the Stroop Color Word Test

The mechanisms causing cognitive problems in chronic pain patients are not well understood. We used the Stroop color word task (SCWT) to investigate distraction-induced analgesia, cognitive performance, and cerebral activation patterns in 29 fibromyalgia (FM) patients (mean age 49.8 years, range 25–64 years) and 31 healthy controls (HC) (mean age 46.3 years, range 20–63 years). In the first study, SCWT was used to investigate distraction-induced analgesia in FM patients. Two versions of the task were applied, one with only congruent color-word images and one with incongruent images. Pressure pain thresholds were assessed using a pressure algometer before, during, and following SCWT. In the second study, reaction times (RTs) were assessed and functional magnetic resonance imaging (fMRI) was used to investigate cerebral activation patterns in FM patients and HC during the SCWT. An event-related task mixing incongruent and congruent images was used. In study one, we found reduced pressure pain sensitivity during SCWT in both groups alike and no statistically significant differences were seen between the incongruent and congruent conditions. The study two revealed longer RTs during the incongruent compared to the congruent condition in both groups. FM patients had longer RTs than HC in both conditions. Furthermore, we found a significant interaction between group and congruency; that is, the group differences in RTs were more pronounced during the incongruent condition. This was reflected in a reduced activation of the caudate nucleus, lingual gyrus, temporal areas, and the hippocampus in FM patients compared to HC. In conclusion, we found normal pain inhibition during SWTC in FM patients. The cognitive difficulties seen in FM patients, reflected in longer RTs, were related to reduced activation of the caudate nucleus and hippocampus during incongruent SCWT, which most likely affected the mechanisms of cognitive learning in FM patients.     

Human Dupuytren's Ex Vivo Culture for the Study of Myofibroblasts and Extracellular Matrix Interactions

Organ fibrosis or “scarring” is known to account for a high death toll due to the extensive amount of disorders and organs affected (from cirrhosis to cardiovascular diseases). There is no effective treatment and the in vitro tools available do not mimic the in vivo situation rendering the progress of the out of control wound healing process still enigmatic.To date, 2D and 3D cultures of fibroblasts derived from DD patients are the main experimental models available. Primary cell cultures have many limitations; the fibroblasts derived from DD are altered by the culture conditions, lack cellular context and interactions, which are crucial for the development of fibrosis and weakly represent the derived tissue. Real-time PCR analysis of fibroblasts derived from control and DD samples show that little difference is detectable. 3D cultures of fibroblasts include addition of extracellular matrix that alters the native conditions of these cells. As a way to characterize the fibrotic, proliferative properties of these resection specimens we have developed a 3D culture system, using intact human resections of the nodule part of the cord. The system is based on transwell plates with an attached nitrocellulose membrane that allows contact of the tissue with the medium but not with the plastic, thus, preventing the alteration of the tissue. No collagen gel or other extracellular matrix protein substrate is required. The tissue resection specimens maintain their viability and proliferative properties for 7 days. This is the first “organ” culture system that allows human resection specimens from DD patients to be grown ex vivo and functionally tested, recapitulating the in vivo situation.     

Volumetric Analysis of the Hypothalamus in Huntington Disease Using 3T MRI: The IMAGE-HD Study

Huntington disease (HD) is a fatal neurodegenerative disorder caused by an expanded CAG repeat in the huntingtin gene. Non-motor symptoms and signs such as psychiatric disturbances, sleep problems and metabolic dysfunction are part of the disease manifestation. These aspects may relate to changes in the hypothalamus, an area of the brain involved in the regulation of emotion, sleep and metabolism. Neuropathological and imaging studies using both voxel-based morphometry (VBM) of magnetic resonance imaging (MRI) as well as positron emission tomography (PET) have demonstrated pathological changes in the hypothalamic region during early stages in symptomatic HD. In this investigation, we aimed to establish a robust method for measurements of the hypothalamic volume in MRI in order to determine whether the hypothalamic dysfunction in HD is associated with the volume of this region. Using T1-weighted imaging, we describe a reproducible delineation procedure to estimate the hypothalamic volume which was based on the same landmarks used in histologically processed postmortem hypothalamic tissue. Participants included 36 prodromal HD (pre-HD), 33 symptomatic HD (symp-HD) and 33 control participants who underwent MRI scanning at baseline and 18 months follow-up as part of the IMAGE-HD study. We found no evidence of cross-sectional or longitudinal changes between groups in hypothalamic volume. Our results suggest that hypothalamic pathology in HD is not associated with volume changes.     

Bone mineral density and carotid atherosclerosis in systemic lupus erythematosus: a controlled cross-sectional study

IntroductionAs osteoporosis is reported to be associated with atherosclerosis in the general population we examined the relationship between bone mass and carotid measurements in patients with systemic lupus erythematosus (SLE) and controls, and possible links between them in SLE.MethodsIn a cross-sectional study, 111 SLE-patient were compared with 111 age- and sex-matched controls, mean age 48.7(12.9) years, 89% were women, of which 51% postmenopausal. Carotid intima media thickness (cIMT), carotid plaque occurrence and echogenicity were determined by B-mode ultrasound and bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA).ResultsBMD and cIMT were inversely associated both in patients and controls. Patients, but not controls, with carotid plaque had higher cIMT at low BMD than at normal BMD, p = 0.010. Logistic regression indicated more than doubled odds ratio (OR) of carotid plaque in patients, particularly in post-menopausal women, than in controls in relation to all BMD measurements. For low BMD at hip, significant increased OR for echolucent plaque was shown for patients compared with controls.In patients, significant impact of age, body mass index, smoking, systolic blood pressure, blood lipids, diabetes mellitus, impaired renal function, low levels of complement C3 and C4, history of nephritis, SLE-damage index and ever use of antimalarial was found for association between BMD and higher cIMT and carotid plaque. In multivariate regression, low C4 was independent contributor to association between total BMD and upper cIMT tertile, accounted for OR (95% confidence interval) of 3.2 (1.03-10.01), and also for association with bilateral carotid plaque, OR of 4.8 (1.03-22.66). The contribution of low C4 for the association between BMD and carotid atherosclerosis was enhanced within the second and third tertiles of total BMD.ConclusionThis study is the first to demonstrate inverse association between BMD and carotid measurements in both SLE-patients and controls. Our results suggest that SLE-patients may suffer higher burden of (sub)clinical atherosclerotic disease, especially presence of both echolucent and echogenic plaque, than controls with the same bone mineral status. Low complement C4 seems to play an important role in earlier development of carotid atherosclerosis already within (sub)normal ranges of total BMD in patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0595-4) contains supplementary material, which is available to authorized users.     

High synovial expression of the inhibitory FcγRIIb in rheumatoid arthritis

Activating Fc gamma receptors (FcγRs) have been identified as having important roles in the inflammatory joint reaction in rheumatoid arthritis (RA) and murine models of arthritis. However, the role of the inhibitory FcγRIIb in the regulation of the synovial inflammation in RA is less known. Here we have investigated synovial tissue from RA patients using a novel monoclonal antibody (GB3) specific for the FcγRIIb isoform. FcγRIIb was abundantly expressed in synovia of RA patients, in sharp contrast to the absence or weak staining of FcγRIIb in synovial biopsies from healthy volunteers. In addition, the expression of FcγRI, FcγRII and FcγRIII was analyzed in synovia obtained from early and late stages of RA. Compared with healthy synovia, which expressed FcγRII, FcγRIII but not FcγRI, all activating FcγRs were expressed and significantly up-regulated in RA, regardless of disease duration. Macrophages were one of the major cell types in the RA synovium expressing FcγRIIb and the activating FcγRs. Anti-inflammatory treatment with glucocorticoids reduced FcγR expression in arthritic joints, particularly that of FcγRI. This study demonstrates for the first time that RA patients do not fail to up-regulate FcγRIIb upon synovial inflammation, but suggests that the balance between expression of the inhibitory FcγRIIb and activating FcγRs may be in favour of the latter throughout the disease course. Anti-inflammatory drugs that target activating FcγRs may represent valuable therapeutics in this disease.