Medical and interventional outcome of dissection of the cervical arteries: Systematic review and meta-analysis.

OBJECTIVE: The management of cervical artery dissections (CADs) is poorly standardized given the scarce number of prospective studies comparing medical and interventional approach to CAD. The aim of the present study is to perform a systematic review and meta-analysis of studies on the treatments of CAD. METHODS: Systematic review and meta-analysis (pre-registered on PROSPERO [CRD42022297512] are performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses [PRISMA] guidelines searching in three different databases [PubMed, Embase and Cochrane Database]) of studies on medical or interventional approach to CAD. Only prospective studies were selected to reduce the risk of bias for the primary meta-analysis. Secondarily, retrospective studies were also included. The aim was to assess the rate of stroke and of stroke/death/bleeding (major or intracranial) by Der Simonian-Laird weights of random effects model. RESULTS: After screening 456 articles, 6 prospective and 22 retrospective studies were identified. Two randomized controlled trials and five retrospective studies comparing antiplatelet (APT) vs oral anticoagulant therapy (OAC) for CAD were identified, as well as four prospective and 17 retrospective single-arm studies evaluating stenting for CAD. In the meta-analysis of randomized controlled trials comparing APT vs OAC, 444 patients were considered, and a borderline significant association was identified in terms of stroke/death in the APT vs OAC groups (odds ratio [OR], 5.6; 95% confidence interval [CI], 0.94-33.38; P = .06; I2 = 0%). No differences were found for the stroke/death/bleeding outcome (OR, 1.25; 95% CI, 0.19-8.18; P = .81; I2 = 0%) between the two treatments. In the meta-analysis including also retrospective studies, overall risk of bias was considered "serious," and 4104 patients were included with no differences in APT vs OAC for stroke (OR, 1.06; 95% CI, 0.53-2.11; P = .29; I2 = 18%); no other comparisons were possible. The pooled meta-analysis of prospective studies on stenting for CAD included four series, for a total of 68 patients, in whom stenting was adopted primarily after failed medical therapy or after traumatic dissection. The pooled rate of stroke/death was 7% (95% CI, 3%-17%; I2 = 0%). The analysis of moderators identified a significant inverse association between the percentage of traumatic dissection and a reduction in postoperative stroke (Y = -1.60-2.02X; P = .03). The pooled rate of the composite endpoint of stroke/death/ or major bleeding was 8% (95% CI, 3%-18%; I2 = 0%). Secondarily, the meta-analysis also included 17 retrospective studies with overall 457 patients and showed a 2.1% pooled rate of stroke/death (95% CI, 1.0%-3.3%; I2 = 0%) and 3.2% stroke/death/bleeding (95% CI, 1.8%-4.7%; I2 = 0%). CONCLUSIONS: Few prospective studies on CAD treatment are present in literature. APT and OAC seem to have similar efficacy in reducing the recurrence of stroke after CAD. No definitive conclusion can be drawn for stenting, due to the low number of studies available. More prospective studies are necessary to evaluate its potential additional value over medical therapy alone in the early phase after CAD.

Type II endoleaks after fenestrated/branched endografting for juxtarenal and pararenal aortic aneurysms.

OBJECTIVE: Persistent type II endoleaks (pEL2s) are not uncommon after endovascular aneurysm repair and their impact on long-term outcomes is well-documented. However, their occurrence and natural history after fenestrated/branched endografting (F/B-EVAR) for juxtarenal and pararenal aneurysms (J/P-AAAs) have been scarcely investigated. Aim of this study was to report incidence, risk factors, and natural history of pEL2 after F/B-EVAR in J/P-AAAs. METHODS: Between 2016 and 2022, all J/P-AAAs undergoing F/B-EVAR were prospectively collected and retrospectively analyzed. EL2 were assessed at the completion angiography, at 30 days and after 6 months as primary outcomes. Preoperative risk factors for pEL2, follow-up survival, freedom from reinterventions (FFR) and aneurysm shrinkage (≥5 mm) were considered as secondary outcomes. RESULTS: Of 132 patients, there were 88 (67%) JAAAs and 44 (33%) PAAAs. Seventeen EL2 (13%) were detected at the completion angiography and 36 (27%) at 30-day computed tomography angiography. The mean follow-up was 28 ± 23 months. Eleven (31%) EL2 sealed spontaneously within 6 months and three new cases were detected, for an overall of 28 pEL2/107 patients (26%) with available radiological follow-up of ≥6 months. Preoperative antiplatelet therapy (odds ratio, 4.7; 95% confidence interval [CI[, 1-22.1; P = .05), aneurysm thrombus volume of ≤40% and six or more patent aneurysm afferent vessels (odds ratio, 7.2; 95% CI, 1.8-29.1; P = .005) were independent risk factors for pEL2. The estimated 3-year survival was 80%, with no difference between cases with and without pEL2 (78% vs 85%; P = .08). The estimated 3-year FFR was 86%, with no difference between cases with and without pEL2 (81% vs 87%; P = .41). Four cases (3%) of EL2-related reinterventions were performed. In 65 cases (49%), aneurysm shrinkage was detected. pEL2 was an independent risk factor for absence of aneurysm shrinkage during follow-up (hazard ratio, 3.2; 95% CI, 1.2-8.3; P = .014). Patients without shrinkage had lower follow-up survival (64% vs 86% at 3-year; P = .009) and FFR (74% vs 90% at 3 years; P = .014) than patients with shrinkage. CONCLUSIONS: PEL2 is not infrequent (26%) after F/B-EVAR for J/P-AAAs and is correlated with preoperative antiplatelet therapy, aneurysm thrombus volume of ≤40%, and six or more patent sac afferent vessels. Patients with pEL2 have a diminished aneurysm shrinkage, which is correlated with lower follow-up survival and FFR compared with patients with aneurysm shrinkage.

Single-Center Experience on the Elective Hybrid Combination of Single Perclose + Angio-Seal VIP 8F Compared With Standard Dual Perclose During Percutaneous Endovascular Aortic Aneurysm Repair.

PURPOSE: This single-center study aimed to assess patients who underwent intentional percutaneous endovascular aortic aneurysm repair (pEVAR) with Hybrid Technique combining a single Perclose (Abbott, Abbott Park, Illinois) Suture-Mediated Closure Device + single Angio-Seal VIP 8F (Terumo, Tokyo, Japan) and compare outcomes with the standard Dual Perclose technique. Materials and Methods: Consecutive elective pEVAR patients treated from November 2022 to November 2023, with healthy femoral accesses and introducer sheaths ≤20 French (F) outer diameter, were included. Coin-toss randomization determined whether a combination of single Perclose Device + single Angio-Seal VIP 8F (Hybrid Technique) or the standard double Perclose Devices (Dual Perclose) was used. In Hybrid Technique, a single Perclose device was positioned at 12 o'clock; a single Angio-Seal VIP 8F was placed after sheaths removal. Dual Perclose followed standard procedure. Primary endpoints included immediate hemostasis, sheath diameter differences, access conversion rate, technical success, and cost analysis. RESULTS: The study involved 60 pEVAR patients (median age=78, interquartile range [IQR]=72-85 years) within the inclusion criteria. In 14 (24%) cases, only 1 femoral access was studied. There were 106 pEVAR accesses, with 58 (54.7%) in the Hybrid Technique group and 48 (45.3%) in the Dual Perclose group. Both groups exhibited homogeneity in pre-operative characteristics and sheath diameter (Hybrid Technique-16F vs Dual Perclose-18F; p=0.202). Immediate hemostasis was achieved in 100% of the Hybrid Technique group vs 87.5% for the Dual Perclose group (p=0.006). Surgical access conversion was unnecessary. Technical success was 100%, with all 6 femoral bleeding cases after Dual Perclose resolved endovascularly, using additional devices. Cost analysis showed a median cost of 330 euros (IQR=0) for the Hybrid Technique group vs 384 euros (IQR=360-456) for the Dual Perclose group (p<0.001). Thirty-day mortality was 3%, in 2 fragile patients, without access-related complications. Multivariate analysis identified Dual Perclose access (odds ratio [OR]=35.6; 95% confidence interval [CI]=18.3-36.8; p<0.001) and obesity (OR=19.7; 95% CI=1.4-23.9.5; p<0.001) as independent risk factors for immediate hemostasis failure. Median follow-up was 134 days (IQR=41-227), with 1 Hybrid Technique case (2%) successfully treated with thrombin injection for a small femoral pseudoaneurysm after 62 days. CONCLUSIONS: The elective Hybrid Technique with combination of single Perclose Device + single Angio-Seal VIP 8F during pEVAR in selected patients appears to be non-inferior to the standard Dual Perclose procedure. It demonstrates a positive trend in reducing immediate hemostasis failure and costs. Both procedures achieved technical success and avoiding surgical access conversions. CLINICAL IMPACT: This study introduces a novel elective hybrid technique combining a single Perclose device with a single Angio-Seal VIP 8Fr for percutaneous endovascular abdominal aortic interventions. Results for hybrid technique showed 100% technical success and efficient immediate hemostasis, while costing less than standard dual Perclose procedure. Both procedures did not require surgical conversions. Despite being a single-center study, it demonstrates potential benefits of the intentional application of this hybrid technique towards minimally invasiveness. Obesity and dual Perclose technique were identified as independent risk factors for hemostasis failure, reaffirming the hybrid technique procedure's efficacy as well as and non-inferiority to standard procedure.

Outcomes of Fenestrated and Branched Endografts for Partial and Total Endovascular Repair of the Aortic Arch - A Systematic Review and Meta-Analysis.

OBJECTIVE: Fenestrated and branched thoracic endovascular aortic repair (F/B-TEVAR) of the aortic arch is a viable approach in patients unsuitable for open repair. The aim was to summarise the published results of manufactured F/B-TEVAR devices for partial and total repair of the aortic arch, and to compare fenestrated with branched configurations. DATA SOURCES: PubMed, Scopus and The Cochrane Library were searched for articles (2018 - 2021) about patients with elective, urgent, or emergency aortic requiring a proximal landing zone in the aortic arch (zone 0 - 1 - 2) and treated by F/B-TEVAR. REVIEW METHODS: The systematic review and meta-analysis were performed according to the PRISMA guidelines. Open repair, supra-aortic trunk (SAT) debranching + standard TEVAR, and in situ physician modified and parallel grafts were excluded. Primary outcomes were technical success and 30 day mortality rate. Secondary outcomes were 30 day major adverse events, and overall survival and procedure related endpoints during follow up. RESULTS: Of 458 articles screened, 18 articles involving 571 patients were selected. Indications for intervention were chronic dissections (50.1%), degenerative aneurysms (39.6%), penetrating aortic ulcers (7.4%), and pseudoaneurysms (2%). F-TEVAR, B-TEVAR, and F+B-TEVAR were used in 38.4%, 54.1%, and 7.5% of patients, respectively. Overall, technical success was 95.9% (95% confidence interval [CI] 0.93 - 0.97; I2 = 0%; p for heterogeneity (Het) = .77) and the 30 day mortality rate was 6.7% (95% CI 0.05 - 0.09; I2 = 0%; p Het = .66). No statistical differences were found comparing fenestrated with branched endografts, except for a higher rate of type I - III endoleaks in F-TEVAR (9.8% vs. 2.6%; p = .034). The overall survival rate and freedom from aortic related death at the one year follow up ranged between 82 - 96.4% and 94 - 94.7%, respectively. Thirteen and five studies were considered at moderate and high risk of bias, respectively. CONCLUSION: F/B-TEVAR for the treatment of the aortic arch, according to experience in dedicated centres, now enjoys a satisfactory level of technical success together with a progressively reduced early mortality rate. There are several limitations, and further studies are needed to reach clearer conclusions.

Carotid Artery Stenting With Double-Layer Stent: A Systematic Review and Meta-Analysis.

BACKGROUND: Carotid artery stenting (CAS) in the treatment of significant stenosis is a cause of stroke due to both plaque prolapse and cerebral embolization. New types of stents with a double-layer structure have been designed to minimize plaque prolapse and embolization; these double-layer stents (DLSs) should be able to reduce the stroke risk; however, definite data on their performance are scarce in the literature. METHODS: A systematic search was performed through PubMed, Scopus, and Cochrane Library, according to PRISMA guidelines; all studies on CAS with DLS (Roadsaver/Casper or CGuard) up to January 1, 2022, with a cohort of at least 20 patients were considered eligible. The present meta-analysis was approved and registered on PROSPERO register (CRD42022297512). Patients with tandem lesions or complete carotid occlusion were excluded from the study. The 30-day stroke rate after CAS was analyzed evaluating the preoperative symptomatic status and DLS occlusion. The estimated pooled rate of events was calculated by random effect model and moderators were evaluated. RESULTS: A total of 14 studies were included in the meta-analysis for a total of 1955 patients. The estimated overall (95% confidence interval [CI]) stroke rate was 1.4% (0.9%-2.2%, I2 = 0%), which was not influenced by the type of DLS used: CGuard 0.8% (0.4%-1.8%, I2 = 0%) versus Roadsaver/Casper 1.5% (0.7%-3.2%, I2 = 0%), p=0.30. The 30-day estimated stroke rate was 1.5% (0.8%-2.9%, I2 = 0%) in asymptomatic and 1.9% (1.0%-3.6%, I2 = 0%) in symptomatic patients, with no influence by moderators. The 30-day DLS occlusion rate was 0.8% (0.4%-1.8%, I2 = 0%). The publication bias assessment identified asymmetry in the asymptomatic populations. CONCLUSION: The overall 30-day stroke rate in CAS with DLS is low (1.4%), with similar results in symptomatic and asymptomatic patients. Acute occlusion of DLS is rare (0.8%). Further studies are necessary to reduce the publication bias for asymptomatic patients. CLINICAL IMPACT: CAS with DLS is associated to a low rate of 30-day stroke in both symptomatic (1.9%) and asymptomatic (1.5%) patients. The type of DLS (CGuard or Roadsaver/Casper) did not affect the 30-day stroke rate.

p.Ser891Ala RET gene mutations in medullary thyroid cancer: Phenotypical and genealogical characterization of 28 apparently unrelated kindreds and founder effect uncovering in Northern Italy.

Applying genetic screening in medullary thyroid cancer (MTC) patients we identified an unexpectedly high frequency of c.2671T>G, p.Ser891Ala RET mutation carriers. Our aim was to: (a) deeply characterize the clinical expression of this mutation, (b) identify the presence of a founder effect in our region. Genetic analysis was performed in 251 relatives from 28 Ser891Ala kindreds, among 108 p.Ser891Ala asymptomatic carriers, 64 were submitted to thyroidectomy: mean age for 10 subjects presenting C-cells hyperplasia was 30.2 ± 13.7 years, raising to 37.9 ± 10.3 in 14 subjects with micro-MTC and to 55.0 ± 14.7 years in 39 subjects with MTC. Age-related progression across histopathological groups CCH/microMTC and MTC were statistically significant: genetic screening in Ser891Ala families could be safely postponed at the age of 14. To investigate the hypothesis of a common ancestor for Ser891Ala mutation we genotyped for 18 polymorphic microsatellite markers encompassing RET locus all subjects belonging to Ser891Ala families and we identified a founder effect, estimating the age of a common ancestor, dating back to 1493 AD. Ethnographic data collected in historical archives support laboratory results; the high prevalence of this mutation in our region could suggest the hypothesis of a population study to realize a preventive intervention in a rare neoplastic disease.

Structural features of the C8 antiviral peptide in a membrane-mimicking environment.

C8, a short peptide characterized by three regularly spaced Trp residues, belongs to the membrane-proximal external functional domains of the feline immunodeficiency virus coat protein gp36. It elicits antiviral activity as a result of blocking cell entry and exhibits membranotropic and fusogenic activities. Membrane-proximal external functional domains of virus coat proteins are potential targets in the development of new anti-HIV drugs that overcome the limitations of the current anti-retroviral therapy. In the present work, we studied the conformation of C8 and its interaction with micellar surfaces using circular dichroism, nuclear magnetic resonance and fluorescence spectroscopy. The experimental data were integrated by molecular dynamics simulations in a micelle-water system. Our data provide insight into the environmental conditions related to the presence of the fusogenic peptide C8 on zwitterionic or negatively charged membranes. The membrane charge modulates the conformational features of C8. A zwitterionic membrane surface induces C8 to assume canonical secondary structures, with hydrophobic interactions between the Trp residues and the phospholipid chains of the micelles. A negatively charged membrane surface favors disordered C8 conformations and unspecific superficial interactions, resulting in membrane destabilization.

Impact of iliac access in elective and non-elective endovascular repair of abdominal aortic aneurysm.

Endovascular aortic repair (EVAR) is nowadays the establishment treatment for patients with abdominal aortic aneurysm (AAA) both in elective and urgent setting. Despite the large applicability and satisfactory results, the presence of hostile iliac anatomy affects both technical and clinical success. This narrative review aimed to report the impact of iliac access and related adjunctive procedures in patients undergoing EVAR in elective and non-elective setting. Hostile iliac access can be defined in presence of narrowed, tortuous, calcified, or occluded iliac arteries. These iliac characteristics can be graded by the anatomic severity grade score to quantitatively assess anatomic complexity before undergoing treatment. Literature shows that iliac hostility has an impact on device navigability, insertion and perioperative and postoperative results. Overall, it has been correlated to higher rate of access issues, representing up to 30% of the first published EVAR experience. Recent innovations with low-profile endografts have reduced large-bore sheaths related issues. However, iliac-related complications still represent an issue, and several adjunctive endovascular and surgical strategies are nowadays available to overcome these complications during EVAR. In urgent settings iliac hostility can significantly impact on particular time sensitive procedures. Moreover, in case of severe hostility patients might be written off for EVAR repair might be inapplicable, exposing to higher mortality/morbidity risk in this urgent/emergent setting. In conclusion, an accurate anatomical evaluation of iliac arteries during preoperative planning, materials availability, and skilled preparation to face iliac-related issues are crucial to address these challenges.

CO2 Angiography in the Standard and Complex Endovascular Repair of the Abdominal Aorta-A Narrative Review of the Literature.

Background/Objectives: Carbon dioxide digital-subtraction angiography (CO2-DSA) is an increasingly adopted technique in endovascular aortic repair (EVAR) and fenestrated/branched EVAR (F/B-EVAR); it is used to reduce the amount of iodinate contrast medium (ICM) and prevent postoperative renal function worsening (PO-RFW). Our aim is to report results from the literature on EVAR and F/B-EVAR procedures using CO2-DSA, together with wider applications in aortic endovascular treatment. Methods: We performed a literature review by searching electronic databases for published data on CO2-DSA during EVAR and F/B-EVAR procedures. The endpoints were postoperative renal function worsening (PO-RFW) and efficacy of intraoperative arterial visualization. Further, applications of CO2 for thoracic endovascular aortic repair (TEVAR) were described. Results: Seventeen studies reporting results on CO2-DSA in EVAR (644 patients) were retrieved. Overall, 372 (58%) procedures were performed with CO2 alone, and 272 (42%) were performed with CO2+ICM. Eight studies analyzed the effect of CO2-DSA angiography on PO-RFW; four studies showed a significantly lower rate of PO-RFW compared to ICM. Five studies (153 patients) analyzed intraoperative arterial visualization with CO2-DSA; renal and hypogastric arteries were effectively visualized in 69% and 99% of cases, respectively. The use of CO2-DSA in F/B-EVAR has not been widely investigated. The largest series reported that PO-RFW was lower in the CO2 vs. ICM group. Conclusions: Carbon dioxide is widely applied in modern aortic endovascular treatment. CO2-DSA for EVAR and F/B-EVAR is an efficient technique for reducing PO-RFW while allowing acceptable arterial intraoperative visualization.

Case report of a sub-occluding thrombus in thoracic aorta: what is the origin?

BACKGROUND: Aortic thrombosis represents a consequence of atherosclerotic disease. In few cases, it can be secondary to large vessel or infective vasculitis. More rarely, aortic thrombosis is the manifestation of a primary malignant neoplasm of the aortic wall. Aortic angiosarcoma is a rare tumour, its clinical presentation is often non-specific and associated signs and symptoms may vary greatly. An early diagnosis is difficult to reach and the presence of metastatic disease is not uncommon at the time of diagnosis. The prognosis is poor overall. CASE SUMMARY: We report the case of a female patient who presented to her GP because of fatigue, hyporexia, weight-loss, and anaemia. An ultrasound of the abdomen showed two small pancreatic lesions, confirmed and described as benign cystic pancreatic lesions on computed tomography (CT) imaging; an incidental thrombus in the superior mesenteric artery was also found on CT imaging. The thoracic CT identified a large thrombotic lesion in the descending thoracic aorta with significant narrowing of the aortic lumen and confirmed the presence of an osteolytic bone lesion on the VIII right rib, in the absence of atherosclerotic disease. Signs of increased metabolic activity in the aortic lumen and in the VIII posterior right rib were shown at a subsequent positron emission tomography. A CT-guided biopsy of the bone lesion was performed and at histology the diagnosis of metastatic angiosarcoma of the aortic wall was made. DISCUSSION: Aortic angiosarcoma is a rare cause of aortic thrombosis, to be taken into consideration in a patient with thrombotic lesions of the aorta in the absence of atherosclerotic disease. The differential diagnosis is difficult because of clinical presentation and radiological features similar to those of inflammatory aortic disease. In our case, the final diagnosis of angiosarcoma was made only by a biopsy of a bone metastatic lesion.

2-hydroxy arachidonic acid: a new non-steroidal anti-inflammatory drug.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) are a family of COX1 and COX2 inhibitors used to reduce the synthesis of pro-inflammatory mediators. In addition, inflammation often leads to a harmful generation of nitric oxide. Efforts are being done in discovering safer NSAIDs molecules capable of inhibiting the synthesis of pro-inflammatory lipid mediators and nitric oxide to reduce the side effects associated with long term therapies. METHODOLOGY/PRINCIPAL FINDINGS: The analogue of arachidonic acid (AA), 2-hydroxy-arachidonic acid (2OAA), was designed to inhibit the activities of COX1 and COX2 and it was predicted to have similar binding energies as AA for the catalytic sites of COX1 and COX2. The interaction of AA and 2OAA with COX1 and COX2 was investigated calculating the free energy of binding and the Fukui function. Toxicity was determined in mouse microglial BV-2 cells. COX1 and COX2 (PGH2 production) activities were measured in vitro. COX1 and COX2 expression in human macrophage-like U937 cells were carried out by Western blot, immunocytochemistry and RT-PCR analysis. NO production (Griess method) and iNOS (Western blot) were determined in mouse microglial BV-2 cells. The comparative efficacy of 2OAA, ibuprofen and cortisone in lowering TNF-α serum levels was determined in C57BL6/J mice challenged with LPS. We show that the presence of the -OH group reduces the likelihood of 2OAA being subjected to H* abstraction in COX, without altering significantly the free energy of binding. The 2OAA inhibited COX1 and COX2 activities and the expression of COX2 in human U937 derived macrophages challenged with LPS. In addition, 2OAA inhibited iNOS expression and the production of NO in BV-2 microglial cells. Finally, oral administration of 2OAA decreased the plasma TNF-α levels in vivo. CONCLUSION/SIGNIFICANCE: These findings demonstrate the potential of 2OAA as a NSAID.

Hydroximic acid derivatives: pleiotropic HSP co-inducers restoring homeostasis and robustness.

According to the "membrane sensor" hypothesis, the membrane's physical properties and microdomain organization play an initiating role in the heat shock response. Clinical conditions such as cancer, diabetes and neurodegenerative diseases are all coupled with specific changes in the physical state and lipid composition of cellular membranes and characterized by altered heat shock protein levels in cells suggesting that these "membrane defects" can cause suboptimal hsp-gene expression. Such observations provide a new rationale for the introduction of novel, heat shock protein modulating drug candidates. Intercalating compounds can be used to alter membrane properties and by doing so normalize dysregulated expression of heat shock proteins, resulting in a beneficial therapeutic effect for reversing the pathological impact of disease. The membrane (and lipid) interacting hydroximic acid (HA) derivatives discussed in this review physiologically restore the heat shock protein stress response, creating a new class of "membrane-lipid therapy" pharmaceuticals. The diseases that HA derivatives potentially target are diverse and include, among others, insulin resistance and diabetes, neuropathy, atrial fibrillation, and amyotrophic lateral sclerosis. At a molecular level HA derivatives are broad spectrum, multi-target compounds as they fluidize yet stabilize membranes and remodel their lipid rafts while otherwise acting as PARP inhibitors. The HA derivatives have the potential to ameliorate disparate conditions, whether of acute or chronic nature. Many of these diseases presently are either untreatable or inadequately treated with currently available pharmaceuticals. Ultimately, the HA derivatives promise to play a major role in future pharmacotherapy.

Membrane-lipid therapy in operation: the HSP co-inducer BGP-15 activates stress signal transduction pathways by remodeling plasma membrane rafts.

Aging and pathophysiological conditions are linked to membrane changes which modulate membrane-controlled molecular switches, causing dysregulated heat shock protein (HSP) expression. HSP co-inducer hydroxylamines such as BGP-15 provide advanced therapeutic candidates for many diseases since they preferentially affect stressed cells and are unlikely have major side effects. In the present study in vitro molecular dynamic simulation, experiments with lipid monolayers and in vivo ultrasensitive fluorescence microscopy showed that BGP-15 alters the organization of cholesterol-rich membrane domains. Imaging of nanoscopic long-lived platforms using the raft marker glycosylphosphatidylinositol-anchored monomeric green fluorescent protein diffusing in the live Chinese hamster ovary (CHO) cell plasma membrane demonstrated that BGP-15 prevents the transient structural disintegration of rafts induced by fever-type heat stress. Moreover, BGP-15 was able to remodel cholesterol-enriched lipid platforms reminiscent of those observed earlier following non-lethal heat priming or membrane stress, and were shown to be obligate for the generation and transmission of stress signals. BGP-15 activation of HSP expression in B16-F10 mouse melanoma cells involves the Rac1 signaling cascade in accordance with the previous observation that cholesterol affects the targeting of Rac1 to membranes. Finally, in a human embryonic kidney cell line we demonstrate that BGP-15 is able to inhibit the rapid heat shock factor 1 (HSF1) acetylation monitored during the early phase of heat stress, thereby promoting a prolonged duration of HSF1 binding to heat shock elements. Taken together, our results indicate that BGP-15 has the potential to become a new class of pharmaceuticals for use in 'membrane-lipid therapy' to combat many various protein-misfolding diseases associated with aging.