IL-8 promotes the calcification of human aortic valve interstitial cells, which is prevented through antagonizing CXCR1 and CXCR2 receptors

Background/Introduction

Inflammation is a key feature of calcific aortic valve stenosis (CAVS) against which there is currently no pharmacological treatment.

Purpose

To verify the hypothesis that interleukin-8 (IL-8), a pro-inflammatory factor involved in arterial calcifications, also promotes the calcification of human aortic valve interstitial cells (hVICs).

Methods

Primary hVICs were isolated from healthy pieces of aortic valves harvested from patients undergoing surgical valve replacement. They were cultured in a pro-calcifying condition (Pi-3.8mM) with or without IL-8 (5 to 50 pg/ml) for up to 21 days. Calcification was analysed by alizarin red staining and calcium content was measured with the o-cresolphthalein complexone method. The viability of hVICs was verified by the MTT assay. The expression of osteogenic (BMP2, OPN, osterix and ALP) and myofibrotic (alpha-SMA, collagen-1, collagen-3 and elastin) markers as well as that of metalloproteases (MMP-2, -9 and -12) was analysed by RT-qPCR. The expression of IL-8 receptors, CXCR-1 and CXCR-2 was evaluated by Western blot and flow cytometry, and the effects of IL-8 were tested in the presence or absence of SCH527123, an antagonist of CXCR-1 and CXCR-2. Finally, the expression of CXCR-1 and -2 and elastin was analysed by immunohistochemistry in the calcified and non-calcified areas of human aortic valve samples. All of these experiments were carried out from valves of at least 5 different donors and a P<0.05 was considered statistically significant.

Results

IL-8 (15 pg/mL) caused a significant ∼2-fold increase in the calcification of hVICs in the Pi condition, compared to the Pi-only condition, without modulation of cell viability. In the presence of Pi, IL-8 exposure significantly stimulated the expression of the transcripts of elastin and MMP-12, an elastase, and reduced that of OPN, a well-known inhibitor of calcification. The effects of IL-8 on hVICs calcification and on the expression of MMP-12, elastin and OPN transcripts were significantly prevented by the addition of SCH527123. In addition, the expression of CXCR-1 and -2 was confirmed in histological samples of human aortic valves. This expression was more pronounced in calcified areas compared to non-calcified areas and co-localized with degraded elastin.

Conclusion

IL-8 promoted the calcification of hVICs in culture. This effect was significantly prevented by antagonizing CXCR-1 and CXCR-2 IL-8 receptors, which we showed for the first time to be expressed by human VICs and aortic valves of patients with CAVS. Further studies are underway to clarify the cellular mechanisms involved.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Fédération Hospitalo-Universitaire REMOD-VHF

Serious central nervous system side effects of cephalosporins: A national analysis of serious reports registered in the French Pharmacovigilance Database

INTRODUCTION

Among antibiotics, Central Nervous System (CNS) adverse drug reactions (ADRs) are often under-suspected and overlooked. Cephalosporins are an important cause of drug-induced CNS ADRs but the characteristics of such ADR have not been fully explored. We aimed to characterize the profile of cephalosporins serious CNS ADRs.

METHOD

We performed an analysis of serious reports recorded in the French Pharmacovigilance database from 1987 to 2017.

RESULTS

A total of 511 serious ADRs reports was analyzed. Patients had a mean age of 67.1 years and were mainly men (52.5%), with a mean creatinine clearance of 32.9 ml/min. The most involved molecules were cefepime (33.1%), ceftriaxone (29.7%), ceftazidime (19.6%), cefotaxime (9%) and cefazoline (2.9%), mostly administered intravenously (87.3%). A CNS history was observed in 25% of the reports (n = 128). Patients exhibited encephalopathy (30.3%), confusional state (19.4%), convulsion (15.1%), myoclonia (9.4%), status epilepticus (9.2%), coma (6.3%) and hallucination (4.3%). The mean time of onset was 7.7 days and the mean duration was 6 days. Cephalosporin plasma levels were recorded for 153 patients (29.9%) and 107 were above the standards including 62 (57.9%) related to renal impairment. Electroencephalograms were performed in 38.2% (n = 195) of the patients and 81% (n = 158) were abnormal.

CONCLUSION

This study characterizes an off-target CNS ADRs of several cephalosporins. Ceftriaxone represented a large part of our reports after cefepime and it would be relevant to warn healthcare professionals. Investigations (EEG, though plasma levels and renal function) can be precious tools for clinicians to make a prompt diagnosis and improve patients' outcomes.

[Mastectomy and immediate reconstruction: Indications, techniques and decision algorithm]

Immediate breast reconstruction indications extend to infiltrating carcinomas, due to new matrix implant coverage techniques and the development of perforator flaps. These techniques allow adjuvant treatments. However, the decision of immediate reconstruction must be discussed with the oncological multidisciplinary team and the benefits/risks must also be evaluated in relation to the morphology of the patients and their co-morbidities. The chosen type of mastectomy: conventional or skin sparing and/or nipple sparing depends on the shape and volume of the breast, the localization of the tumor in the breast and the distance from the nipple areola complex (NAC). We describe an algorithm to allow, in the case of therapeutic mastectomy with or without adjuvant radiotherapy, an immediate reconstruction with implants or free or pedicled flaps.

[Decision algorithm in immediate breast reconstruction]

Immediate breast reconstruction showed many advantages in terms of aesthetic and functional results and improvement of quality of life when compared to delayed breast reconstruction. Previous radiotherapy or the use of adjuvant treatments such as radiation therapy, or chemotherapy are no longer a contraindication for immediate breast reconstruction. However, it is important to respect certain rules in order to decrease the risk of complications: the choice of reconstruction technique, the management of the skin envelope according to the breast shape you want to create, the time delay between the first and the second stage of reconstruction depending on a possible adjuvant treatment.

[Deep alkali burns: Evaluation of a two-step surgical strategy]

INTRODUCTION

Chemical burns are rare but often lead to deep cutaneous lesions. Alkali agents have a deep and long lasting penetrating power, causing burns that evolve over several days. The local treatment for these patients is excision of the wound and split thickness skin graft. Early excision and immediate skin grafting of alkali burns are more likely to be complicated by graft failure and delayed wound healing. We propose a two-step method that delays skin grafting until two-three days after burn wound excision.

RESULTS

Our population included 25 controls and 16 cases. Men were predominant with a mean age of 41.9 years. In 78% of cases, burns were located on the lower limbs. The mean delay between the burn and excision was 16.5 days. In cases, the skin graft was performed at a mean of 11.3 days after the initial excision. We did not unveil any significant difference between both groups for the total skin surface affected, topography of the burns and the causal agent. Wound healing was significantly shorter in cases vs controls (37.5 days vs 50.3 days; P<0.025). Furthermore, we observed a decreased number of graft failures in cases vs controls (13.3% vs 46.7%; P=0.059).

CONCLUSION

Our study shows the relevance of a two-step surgical strategy in patients with alkali chemical burns. Early excision followed by interval skin grafting is associated with quicker wound healing and decreased rate of graft failure.

[Rational use of distraction osteogenesis in craniofacial surgery]

Distraction osteogenesis, initially developed by Ilizarov for limb, is the tissular extension caused by the progressive space of the osseous pieces following an osteotomy. Distraction is osteogenesic and histogenic. Twenty-five years ago, at the instigation of McCarthy, this technique was used to handle the craniofacial malformations in the various floors of the face : mandibular, mediofacial and cranial. The most wide-spread protocols respect a latency period from 0 to 7 days, a rhythm of distraction from 1 to 2mm a day in 2 at 4 times and a period of consolidation from 4 to 8 weeks. Distraction is the result of the inventiveness of the pioneers then the work to always adapt to the multiple complex clinical situations. The surgeon has to choose between internal or external materials allowing a mono- or multi-vectorial extension, in osseous and/or dental anchoring. The mandibular distraction is very effective for the treatment of the secondary obstructive syndromes in the unilateral or bilateral severe hypomandibular malformations. She also allows desobstruction of the superior airways within the framework of the mediofacial hypoplasies as well as the secondary treatment of the growth defects in cleft lips and palates. Finally, the distraction osteogenesis enhanced reliability of the fronto-facial advancement in early and secondary treatment of craniofaciosynostosis. This is a real support of the facial growth, which has to be included in a plan of global treatment.

Unexpectedly long half-life of metformin elimination in cases of metformin accumulation

INTRODUCTION

In a study of the oral administration of a single dose of metformin to healthy participants, the estimated half-life (t½ ) for the elimination of the drug from erythrocytes was found to be 23.4 h (compared with 2.7 h for metformin in plasma). However, these pharmacokinetic indices have not been well defined in metformin accumulation.

METHODS

We systematically reviewed all the data on plasma and erythrocyte metformin assays available in our centre. We then selected patients with a plasma metformin concentration ≥ 5 mg/l and in whom the metformin concentration had been remeasured once or more at least 5 days after admission.

RESULTS

Twelve patients met the aforementioned criteria. All but one of these patients displayed generally severe lactic acidosis on admission (mean ± sd pH and lactate: 6.88 ± 0.35 and 14.8 ± 6.56 mmol/l, respectively) and 11 were treated with dialysis. The mean ± sd time interval between the first and last blood sample collections for metformin measurement was 8.3 ± 3.2 days (range 5-14 days). Five days after the first sample had been collected, metformin was still detectable in plasma and in erythrocytes in all patients. Metformin remained detectable for up to 13 days (both in plasma and in erythrocytes). The estimated mean terminal t½ for metformin in plasma and erythrocytes was 51.9 and 43.4 h, respectively.

CONCLUSIONS

The prolonged elimination of accumulated metformin (even after dialysis therapy) challenges the traditional view that the drug clears rapidly because of a short half-life in plasma.

[Massive panniculectomy and bilateral subtotal mastectomy in a case of calciphylaxis: A case report and up date]

Calciphylaxis or calcific arteriolopathy is a rare, life-threatening obstructive pathology of the small cutaneous and subcutaneous vessels. It mainly affects patients with chronic renal failure but it also has been described in patients with normal renal function. The principal risks factors apart from renal failure and phosphocalcic metabolism imbalance are: the female sex, obesity, peripheral vascular disease, diabetes and oral anti-coagulation. We present a very rare case of abdominal, mammarian and upper thighs calciphylaxis in a patient with normal renal function. She presented a severe obesity with a recent important loss of weight and had been treated by oral anticoagulants for a long time. She benefited of a multidisciplinary approach with dermatologists, plastic surgeons and anesthesists permitting a recovery in fourteen weeks. Multidisciplinary approach is necessary but the place of the surgery is not well defined. We report a case in which early and wide surgical approach permitted to obtain a favourable evolution of the pathology. Then, we propose a therapeutic strategy after review of the literature.

[Cell therapy for stroke: from myth to reality]

INTRODUCTION

Stroke is one of the leading causes of death and disability worldwide. Intravenous recombinant tissue plasminogen activator is the only available therapy for acute ischemic stroke, but its use is limited by a narrow therapeutic window and cannot stimulate endogenous repair and regeneration of damaged brain tissue. Stem cell-based approaches hold much promise as potential novel treatments to restore neurological function after stroke.

STATE OF THE ART

In this review, we summarize data from preclinical and clinical studies to investigate the potential application of stem cell therapies for treatment of stroke. Stem cells have been proposed as a potential source of new cells to replace those lost due to central nervous system injury, as well as a source of trophic molecules to minimize damage and promote recovery. Various stem cells from multiple sources can generate neural cells that survive and form synaptic connections after transplantation in the stroke-injured brain. Stem cells also exhibit neurorevitalizing properties that may ameliorate neurological deficits through stimulation of neurogenesis, angiogenesis and inhibition of inflammation.

PERSPECTIVES/CONCLUSION

Performed in stroke, cell therapy would decrease brain damage and reduce functional deficits. After the damage has been done, it would still improve neurological functions by activating endogenous repair. Nevertheless, many questions raised by experimental studies particularly related to long-term safety and technical details of cell preparation and administration must be resolved before wider clinical use.

Priming of late endothelial progenitor cells with erythropoietin before transplantation requires the CD131 receptor subunit and enhances their angiogenic potential

BACKGROUND

 Endothelial colony-forming cells (ECFCs) are promising candidates for cell therapy of ischemic diseases. Erythropoietin (EPO) is a cytokine that promotes angiogenesis after ischemic injury. EPO receptors (EPORs) classically include two EPOR subunits, but may also associate with the β-common chain (CD131) in a newly identified receptor involved in EPO cytoprotective effects.

OBJECTIVE

The aim was to take advantage of the proangiogenic properties of EPO to enhance ECFC graft efficiency. We postulated that priming ECFCs by adding epoietin α in culture medium prior to experiments might increase their angiogenic properties. We also explored the role of the CD131 subunit in EPO priming of ECFCs.

METHODS AND RESULTS

By western blotting on cord blood ECFC lysates, we showed that EPOR and CD131 expression increased significantly after EPO priming. These proteins coimmunoprecipitated and colocalized, suggesting that they are covalently bound in ECFCs. EPO at 5 IU mL(-1) significantly stimulated proliferation, wound healing, migration and tube formation of ECFCs. EPO priming also increased ECFC resistance to H2 O2-induced apoptosis and survival in vivo. Similarly, in vivo studies showed that, as compared with non-primed ECFC injection, 5 IU mL(-1) EPO-primed ECFCs, injected intravenously 24 h after hindlimb ischemia in athymic nude mice, increased the ischemic/non-ischemic ratios of hindlimb blood flow and capillary density. These effects were all prevented by CD131 small interfering RNA transfection, and involved the phosphoinositide 3-kinase-Akt pathway.

CONCLUSION

These results highlight the potential role of EPO-primed ECFCs for cell-based therapy in hindlimb ischemia, and underline the critical role of CD131 as an EPO coreceptor.

Circulating lipoprotein-associated phospholipase A2 in high-grade carotid stenosis: a new biomarker for predicting unstable plaque

OBJECTIVE

To test plasma levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) in patients with high-grade carotid stenosis according to plaque histology.

METHODS

This cross-sectional single-centre study included patients with ≥70% North American Symptomatic Carotid Endarterectomy Trial (NASCET) carotid stenosis, who were treated surgically. Serum Lp-PLA2 and high-sensitivity C-reactive protein (hs-CRP) were determined on the day of surgery. Histopathological analysis classified carotid plaque as stable or unstable, according to AHA classification.

RESULTS

Of the 42 patients (mean age 70.4 ± 10.5 years; 67% men), neurological symptoms were present in 16 (38%). Unstable plaques were found in 23 (55%). Median plasma level of Lp-PLA2 was significantly higher in patients with unstable plaque compared to those with stable plaque (222.4 (174.9-437.5) interquartile range (IQR) 63.5 vs. 211.1 (174.9-270.6) IQR 37.2 ng ml(-1); p = 0.02). Moreover, median Lp-PLA2 level were higher in asymptomatic patients with unstable plaque (226.8 ng ml(-1) (174.9-437.5) IQR 76.8) vs. stable plaque (206.9 ng ml(-1) (174.9-270.6) IQR 33.7; p = 0.16). Logistic regression showed that only the neurological symptoms (OR = 30.9 (3.7-244.6); p < 0.001) and the plasma Lp-PLA2 level (OR = 1.7 (1.1-12.3); p = 0.03) were independently associated with unstable carotid plaque as defined by histology.

CONCLUSIONS

This study showed that circulating Lp-PLA2 was increased in patients with high-grade carotid stenosis and unstable plaque. Lp-PLA2 may be a relevant biomarker to guide for invasive therapy in asymptomatic patients with carotid artery disease.