TGF-β1 decreases CHOP expression and prevents cardiac fibroblast apoptosis induced by endoplasmic reticulum stress

Transforming growth factor-beta 1 (TGF-β1) is a cytokine with marked pro-fibrotic action on cardiac fibroblasts (CF). TGF-β1 induces CF-to-cardiac myofibroblast (CMF) differentiation, defined by an increase in α-smooth muscle cells (α-SMA), collagen secretion and it has a cytoprotective effect against stimuli that induce apoptosis. In the Endoplasmic Reticulum (ER) lumen, misfolded protein accumulation triggers ER stress and induces apoptosis, and this process plays a critical role in cell death mediated by Ischemia/Reperfusion (I/R) injury and by ER stress inducers, such as Tunicamycin (Tn). Here, we studied the regulation of CHOP, a proapoptotic ER-stress-related transcription factor in CF under simulated I/R (sI/R) or exposed to Tn. Even though TGF-β1 has been shown to participate in ER stress, its regulatory effect on CF apoptosis and ER stress-induced by sI/R or TN has not been evaluated yet. CF from neonatal rats were exposed to sI/R, and cell death was evaluated by cell count and apoptosis by flow cytometry. ER stress was assessed by western blot against CHOP. Our results evidenced that sI/R (8/24) h or Tn triggers CF apoptosis and an increase in CHOP protein levels. TGF-β1 pre-treatment partially prevented apoptosis induced by sI/R or Tn. Furthermore, TGF-β1 pre-treatment completely prevented CHOP increase by sI/R or Tn. Additionally, we found a decrease in α-SMA expression induced by sI/R and in collagen secretion induced by Tn, which were not prevented by TGF-β1 treatment. In conclusion, TGF-β1 partially protects CF apoptosis induced by sI/R or Tn, through a mechanism that would involve ER stress.

In cardiac fibroblasts, interferon-beta attenuates differentiation, collagen synthesis, and TGF-β1-induced collagen gel contraction

Cardiac fibroblasts (CF) play a key role in the homeostasis of the extracellular matrix in cardiac tissue and are newly recognized as inflammatory supporter cells. Besides, CF-to-Cardiac myofibroblast differentiation is commanded by TGF-b, through SMAD signaling pathways, and these last cells are strongly implicated in cardiac fibrosis. In the heart IFN-β is produced by CF; however, the role of IFN-β, STAT proteins, and STAT-homo or heterodimers in the regulation of CF function with or without a fibrotic environment is unknown. CF were isolated from hearts of adult rats, and by western blot analysis we studied STAT1, STAT2, and STAT3 phosphorylation and through specific siRNA against these proteins we analyzed their role in CF functions such as differentiation (α-SMA expression); and pro-collagen type-I synthesis and secretion expression levels; collagen gels contraction and CF migration. In cultured adult rats CF, IFN-β increases phosphorylation of STAT1, STAT2, and STAT3. Both STAT1 and STAT2 were involved in decreasing α-SMA and CF migration induced by TGF-β1. Also, IFN-β through STAT1 regulated pro-collagen type-I protein expression levels, and collagen gels contraction induced by TGF-β1. STAT3 was not involved in any effects of IFN-β studied. In conclusion, IFN-β through STAT1 and STAT2 shows antifibrotic effects on CF TGF-β1-treated, whereas STAT3 did not participate in such effect.

Cardiac fibroblasts as sentinel cells in cardiac tissue: Receptors, signaling pathways and cellular functions

Cardiac fibroblasts (CF) not only modulate extracellular matrix (ECM) proteins homeostasis, but also respond to chemical and mechanical signals. CF express a variety of receptors through which they modulate the proliferation/cell death, autophagy, adhesion, migration, turnover of ECM, expression of cytokines, chemokines, growth factors and differentiation into cardiac myofibroblasts (CMF). Differentiation of CF to CMF involves changes in the expression levels of various receptors, as well as, changes in cell phenotype and their associated functions. CF and CMF express the β2-adrenergic receptor, and its stimulation activates PKA and EPAC proteins, which differentially modulate the CF and CMF functions mentioned above. CF and CMF also express different levels of Angiotensin II receptors, in particular, AT1R activation increases collagen synthesis and cell proliferation, but its overexpression activates apoptosis. CF and CMF express different levels of B1 and B2 kinin receptors, whose stimulation by their respective agonists activates common signaling transduction pathways that decrease the synthesis and secretion of collagen through nitric oxide and prostacyclin I2 secretion. Besides these classical functions, CF can also participate in the inflammatory response of cardiac repair, through the expression of receptors commonly associated to immune cells such as Toll like receptor 4, NLRP3 and interferon receptor. The activation by their respective agonists modulates the cellular functions already described and the release of cytokines and chemokines. Thus, CF and CMF act as sentinel cells responding to a plethora of stimulus, modifying their own behavior, and that of neighboring cells.

Bispectral index monitoring may not reliably indicate cerebral ischaemia during awake carotid endarterectomy † †This study was conducted in the Department of Neurosurgery, Newcastle General Hospital, Newcastle Upon Tyne NE4 6BE, UK. Preliminary results were presented at the British Neurosurgery Research Group Meeting, Sheffield, March 29–30, 2001

BACKGROUND

Intraoperative ischaemia during carotid cross-clamping in patients undergoing carotid endarterectomy (CEA) is a major complication and prompt recognition of insufficient collateral blood supply is crucial. Electroencephalogram (EEG) is believed to be one of the useful forms of monitoring cerebrovascular insufficiency during CEA. The aim of this study was to evaluate the utility of bispectral index (BIS) monitoring, a processed EEG parameter, for the reliable detection of intraoperative cerebral ischaemia during awake CEA.

METHODS

We monitored 52 patients continuously with the BIS monitor together with assessment of neurological function (contralateral upper and lower limb strength and the verbal component of the Glasgow Coma Scale for speech) in patients undergoing awake CEA.

RESULTS

Overall mean BIS value in all patients was 96 (SD 2.9). In five patients who showed clinical evidence of cortical ischaemia during carotid cross-clamping, there was no change in the original range of BIS values throughout the procedure (96.7 [3.2]). In one patient BIS values decreased to 38 about 5 min after the incision and recovered within the next 10 min. The mean BIS value in the remaining 46 patients who did not develop clinical signs of ischaemia was 95.4 (2.6). Three cases are presented which demonstrate the inability of the BIS monitor to detect cerebral ischaemia.

CONCLUSIONS

Lack of correlation of BIS with the signs of cerebral ischaemia during CEA makes it unreliable for detection of cerebrovascular insufficiency. We conclude that awake neurological testing is the preferred method of monitoring in these patients.

[Validation of a version in Spanish of the Yale-Brown Obsessive-Compulsive Scale]

INTRODUCTION

The objective of this study is to validate a version in Spanish of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS).

METHOD

We administered to 20 patients with obsessive-compulsive disorder (OCD) the Maudsley Obsessive-Compulsive Inventory (MOI) and a version in Spanish of the Y-BOCS. The application of the last one was performed by an interviewer, filmed, and then watched and rated by other 4 observers. In addition, the opinion of the treating psychiatrist about the severity of the patient's symptoms was registered. The interviewer and the observers were named raters.

RESULTS

The mean scores of the Y-BOCS assigned by the 4 observers were from 18.35 to 19.55; the maximum scores, from 34 to 35; and the minimum scores, from 1 to 5. The Pearson's correlations between raters were significant for all cases (r>0.86 and p<0.001). For all raters, Y-BOCS scores significantly correlated with MOI scores (p<0.001) and the opinion of the treating psychiatrist (p<0.05). We did not find significant correlation between the last one and MOI scores. The Cronbach's coefficients ranged from 0.8789 to 0.9488.

CONCLUSIONS

The Spanish version of the Y-BOCS is reliable, homogeneous and valid for quantification of the obsessive-compulsive symptoms, and has more correlation with the opinion of the treating psychiatrist than the MOI.

Comparative in vitro activity of moxifloxacin by E-test against Streptococcus pyogenes

Macrolides are currently used to treat Streptococcus pyogenes infections where allergy or resistance prevents the use of penicillin. However, growing macrolide resistance is now seen worldwide, with rates of 5%-40% being reported. In this context it is therefore important to have other therapeutic options. The aim of this study was to ascertain the potential role of moxifloxacin, a third-generation fluoroquinolone, in the treatment of infections caused by group A S. pyogenes. The antimicrobial susceptibilities of S. pyogenes isolated from 197 adult patients with pharyngotonsillitis were analyzed by the E-test. Twelve percent of the isolates were resistant to macrolides, and 5% showed diminished susceptibility toward penicillin; none of the strains were resistant to cefotaxime or to moxifloxacin (90% minimum inhibitory concentration, 0.25 microg/mL). Therefore, moxifloxacin may be a therapeutic option in the management of S. pyogenes infections when penicillin cannot be used or when macrolide resistance may be a local issue. Clinical studies of moxifloxacin in pharyngotonsillitis are warranted.