Nerve injury elevates functional Cav3.2 channels in superficial spinal dorsal horn.

Cav3 channels play an important role in modulating chronic pain. However, less is known about the functional changes of Cav3 channels in superficial spinal dorsal horn in neuropathic pain states. Here, we examined the effect of partial sciatic nerve ligation (PSNL) on either expression or electrophysiological properties of Cav3 channels in superficial spinal dorsal horn. Our in vivo studies showed that the blockers of Cav3 channels robustly alleviated PSNL-induced mechanical allodynia and thermal hyperalgesia, which lasted at least 14 days following PSNL. Meanwhile, PSNL triggered an increase in both mRNA and protein levels of Cav3.2 but not Cav3.1 or Cav3.3 in rats. However, in Cav3.2 knockout mice, PSNL predominantly attenuated mechanical allodynia but not thermal hyperalgesia. In addition, the results of whole-cell patch-clamp recordings showed that both the overall proportion of Cav3 current-expressing neurons and the Cav3 current density in individual neurons were elevated in spinal lamina II neurons from PSNL rats, which could not be recapitulated in Cav3.2 knockout mice. Altogether, our findings reveal that the elevated functional Cav3.2 channels in superficial spinal dorsal horn may contribute to the mechanical allodynia in PSNL-induced neuropathic pain model.

Usefulness of Myocardial Strain and Twist for Early Detection of Myocardial Dysfunction in Patients With Autoimmune Diseases.

Cardiac involvement in autoimmune diseases (AD) is common but underdiagnosed due to a lack of sensitive imaging methods. We aim to evaluate the characteristics of left ventricular (LV) systolic dysfunction in patients with AD using deformational parameters from 2-dimensional speckle-tracking echocardiography (STE). We retrospectively enrolled 86 AD patients and 71 healthy controls. All subjects underwent transthoracic echocardiography and STE to analyze LV strain and twist. A twist-radial displacement loop was constructed to investigate the relation between LV contractility and dimension. In AD patients, 68 had preserved LV ejection fraction (EF ≥ 50%), and 18 had reduced LVEF (EF < 50%). The patients with preserved LVEF exhibited significantly lower values of global longitudinal, circumferential, and radial strain than controls (-19.11 ± 4.18 vs -21.49 ± 2.53%, -25.17 ± 5.04% vs -27.37 ± 2.87%, 17.68 ± 5.69% vs 21.17 ± 6.44%, respectively; all p <0.01) and a marked attenuation in peak twist (14.24 ± 5.57 vs 18.10 ± 5.97, p <0.01) attributed to impaired apical rotation (9.03 ± 5.17 vs 12.79 ± 5.99, p <0.01). AD patients were more likely to present with abnormal loop types with flat ascending slope and delayed peak twist time. In conclusion, abnormal strain and twist precede deterioration in LVEF, suggesting early myocardial involvement in AD. STE can be used as a good alternative for early detection of myocardial dysfunction in AD patients.

The quest for diagnostic approaches of cardiac involvement in polymyositis and dermatomyositis.

Polymyositis (PM) and dermatomyositis (DM) are autoimmune diseases characterized by inflammation of skeletal muscle, primarily manifesting as chronic muscle weakness. Extramuscular organs can also be affected. Cardiac involvement is one of the visceral organ damages whose prevalence is underestimated and is a marker of poor prognosis leading to irreversible dysfunction or even death. Although early and accurate recognition of cardiac involvement remains a key barrier to improving survival in PM/ DM patients, considerable progress has been made, and an overview will be provided in this review. The new concept of multimodality imaging, which involves an integrated approach of echocardiography (Echo), cardiac magnetic resonance and sometimes positron emission tomography (PET), can facilitate diagnosis. The development of ultrasound technology, including strain analysis, stress Echo and contrast-enhanced Echo, helps disclose early cardiac dysfunction more sensitively than conventional Echo. Cardiac magnetic resonance unveils silent, acute or chronic myocarditis in PM/DM and is used to monitor treatment efficacy due to its excellent tissue characterization. PET can be useful thanks to the appearance of new tracers that can eliminate the effects of glucose uptake by normal cardiomyocytes. The sensitivity of endomyocardial biopsy may be increased by targeted sampling with the guidance of cardiac imaging. Troponin I is specific to cardiac injury, and investigations into antibodies against cardiac tissue are being carried out. Disease-specific mechanisms and therapies are also discussed to give more insights into cardiac involvement in PM and DM.

Antigen retrieval pre-treatment causes a different expression pattern of Cav3.2 in rat and mouse spinal dorsal horn.

Cav3 channels consist of three isoforms, Cav3.1 (α1G), Cav3.2 (α1H), and Cav3.3 (α1I), which produce low-threshold spikes that trigger burst firings in nociceptive neurons of the spinal dorsal horn (SDH) and dorsal root ganglion (DRG). Although Cav3.2 plays a crucial role in pathological pain, its distribution in SDH still remains controversial. One study showed that Cav3.2 is ubiquitously expressed in neurons, but another study implied that Cav3.2 is expressed restricted to astrocytes. To unravel these discrepancies, we used methods of immunohistochemistry either with or without antigen retrieval (AR) pre-treatment to detect Cav3 in SDH and DRG from both rats and mice. Moreover, Cav3.2 mRNA was detected in mice SDH using in situ hybridization. We found that the expression pattern of Cav3.2 but not Cav3.1 and Cav3.3 in SDH were largely different with or without AR pre-treatment, which showed a neuron-like and an astrocyte-like appearance, respectively. Double staining further demonstrated that Cav3.2 was mainly co-stained with the neuronal marker NeuN in the presence of AR but was with glial fibrillary acidic protein (GFAP, marker for astrocytes) in the absence of AR pre-treatment. Importantly, Cav3.2 mRNA was mainly co-localized with Cav3.2 but not GFAP. Together, our findings indicate that AR pre-treatment or not impacts the expression pattern of Cav3.2, which may make a significant contribution to the future study of Cav3.2 in SDH.

Short-term and 1-year outcomes after MitraClip therapy in functional versus degenerative mitral regurgitation patients: a systematic review and meta-analysis.

BACKGROUND: Differences in short-term and 1-year outcomes of percutaneous edge-to-edge mitral repair between patients with functional and degenerative mitral regurgitation (MR) remain unclear. We performed a systematic review and meta-analysis to investigate the safety and efficacy of MitraClip (MC) in patients with different MR etiologies. METHODS: This study systematically searched three common databases for studies on MC therapy until November 2017. The studies meeting the standard inclusion criteria were included. The data at baseline, short-term and 1-year clinical and echocardiographic outcomes were obtained and analyzed. All data were checked by another reviewer. RESULTS: Thirteen studies totalling 2,351 patients investigating the short-term and 1-year outcomes of MC in patients with functional MR (FMR) versus degenerative MR (DMR) were included for further analysis. FMR patients presented a higher risk profile at baseline. There was no difference in short-term outcomes between DMR and FMR for post-procedural MR grade 0-2 (76.8% vs. 77.1%; P=0.428), mean trans-mitral gradient (3.92 vs. 3.50 mmHg; P=0.098), 30-day mortality rate (0.05% vs. 0.03%; P=0.118) and 30-day NYHA I-II (85.3% vs. 78.7%; P=0.211). FMR patients had a higher rate of acute procedural success compared to the DMR patient group (91.2% vs. 95.2%; P=0.016). A greater portion of DMR patients implanted two or more MCs than the FMR patients (41.4% vs. 35.7%; P=0.043). For the 1-year outcomes, no difference was found in the mortality rate (13.0% vs. 15.2%; P=0.268) and proportion of patients with post-procedural MR grades 0-2 (75.0% vs. 80.7%; P=0.106). CONCLUSIONS: Despite a higher risk profile in FMR patients, the short-term and 1-year outcomes were not significantly different. We conclude that MC therapy is similar between FMR and DMR patients until 1-year follow-up. Large randomized trials are warranted to fully and further assess the clinical impact of the procedure in these two MR etiologies over a longer period of time.