Mitochondria-targeted antioxidant SKQ1 protects cornea from oxidative damage induced by ultraviolet irradiation and mechanical injury

Background

Cornea protects the eye against natural and anthropogenic ultraviolet (UV) damage and mechanical injury. Corneal incisions produced by UV lasers in ophthalmic surgeries are often complicated by oxidative stress and inflammation, which delay wound healing and result in vision deterioration. This study trialed a novel approach to prevention and treatment of iatrogenic corneal injuries using SkQ1, a mitochondria-targeted antioxidant approved for therapy of polyethiological dry eye disease.

Methods

Rabbit models of UV-induced and mechanical corneal damage were employed. The animals were premedicated or treated with conjunctival instillations of 7.5?μM SkQ1. Corneal damage was assessed by fluorescein staining and histological analysis. Oxidative stress in cornea was monitored by measuring malondialdehyde (MDA) using thiobarbituric acid assay. Total antioxidant activity (AOA) was determined using hemoglobin/H₂O₂/luminol assay. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were measured using colorimetric assays.

Results

In both models corneas exhibited fluorescein-stained lesions, histologically manifesting as basal membrane denudation, apoptosis of keratocytes, and stromal edema, which were accompanied by oxidative stress as indicated by increase in lipid peroxidation and decline in AOA. The UV-induced lesions were more severe and long healing as corneal endothelium was involved and GPx and SOD were downregulated. The treatment inhibited loss of keratocytes and other cells, facilitated re-epithelialization and stromal remodeling, and reduced inflammatory infiltrations and edema thereby accelerating corneal healing approximately 2-fold. Meanwhile the premedication almost completely prevented development of UV-induced lesions. Both therapies reduced oxidative stress, but only premedication inhibited downregulation of the innate antioxidant activity of the cornea.

Conclusions

SkQ1 efficiently prevents UV-induced corneal damage and enhances corneal wound healing after UV and mechanical impacts common to ocular surgery. Its therapeutic action can be attributed to suppression of mitochondrial oxidative stress, which in the first case embraces all corneal cells including epitheliocytes, while in the second case affects residual endothelial cells and stromal keratocytes actively working in wound healing. We suggest SkQ1 premedication to be used in ocular surgery for preventing iatrogenic complications in the cornea.

     

Challenges on the road to a multicellular bioartificial liver

Over recent years, the progress in the development of a bioartificial liver (BAL) as an extracorporeal device or as a tissue engineered transplantable organ has been immense. However, many important BAL characteristics that are necessary to meet clinical demands have not been sufficiently addressed. This review describes the existing challenges in the development of a BAL for clinical applications, highlighting multicellularity and sinusoidal microarchitecture as crucial BAL characteristics to fulfil various liver functions. Currently available sources of nonparenchymal liver cells, such as endothelial cells, cholangiocytes and macrophages, used in BAL development are defined. Also, we discuss the recent studies on the reconstruction of the complex liver sinusoid microarchitecture using various liver cell types. Moreover, we highlight some other aspects of a BAL, such as liver zonation and formation of a vascular as well as biliary network for an adequate delivery, biotransformation and removal of substrates and waste products. Finally, the benefits of a multicellular BAL for the pharmaceutical industry are briefly described. Copyright © 2016 John Wiley & Sons, Ltd.     

Low Prevalence Rate of Indeterminate Serological Human Immunodeficiency Virus Results among Pregnant Women from Burkina Faso,West Africa

Rapid human immunodeficiency virus (HIV) antibody tests have been adopted into national guidelines for HIV testing in many countries in sub-Saharan Africa. One goal of HIV rapid testing is to minimize the occurrence of indeterminate results. From January 2005 to December 2007, plasma (or serum) samples from pregnant women in Bobo-Dioulasso (Burkina Faso, West Africa) were screened for HIV by using two rapid tests (the Determine HIV1/2 test [Abbott] and Genie II HIV-1/HIV-2 [Bio-Rad]) through a sequential algorithm prior to enrollment of HIV-1-infected women in a prevention of mother-to-child transmission (PMTCT) trial (WHO/ANRS 1289 Kesho Bora trial). Samples exhibiting indeterminate results (Determine positive and Genie II negative) were further tested with a fourth-generation HIV enzyme immunoassay (EIA) (Murex HIV Ag/Ab combination in 2005 and 2006 and Vironostika HIV Uni-Form II Ag/Ab in 2007). If positive, they were finally assessed for HIV-1 RNA (Generic HIV-1 RNA viral load assay; Biocentric). From a total of 44,653 samples tested, 597 (1.3%) showed indeterminate results. Of these, 367 could be analyzed by EIA. Only 15 (15/367, 4.1%) samples were found EIA reactive. Of these, 11 could be tested for HIV-1 RNA. All were HIV-1 RNA negative. In our clinical practice, pregnant women with such indeterminate results are now reassured during posttest counseling that they are very unlikely to be infected with HIV-1. As a consequence, such women with indeterminate results can reliably be considered negative when urgent clinical decisions (such as providing PMTCT prophylaxis) need to be taken.In sub-Saharan Africa, rapid testing for human immunodeficiency virus (HIV) is the most efficient and sometimes the only feasible way to quickly provide information about HIV status among adults and children ≥18 months of age (6, 29). In contrast to enzyme immunoassays (EIAs) and Western blot assays (WBs), HIV rapid tests are relatively cheap, easy to use, and fast to perform. Most of them do not require refrigeration, sophisticated laboratory equipment, skilled technicians, and an electricity supply. Results from serum, plasma, whole-blood, urine, or saliva samples are obtained by visual reading after a few minutes. Some of the rapid tests can distinguish HIV type 1 (HIV-1) from HIV type 2 (HIV-2). They are also accurate and reliable as a result of applying a quality system approach recommended by the World Health Organization (WHO) (36). Due to their low cost and technical advantages, they have been adopted into national HIV voluntary counseling and testing (VCT) guidelines in many African countries. Their sensitivity and specificity have been studied in Kenya (12), Tanzania (22), Uganda (15), Zambia (30), South Africa (25), Cameroon (1), Central African Republic (24), Democratic Republic of Congo (19), Ghana (2), Ivory Coast (32), and Burkina Faso (23, 28).One objective for rapid HIV testing is to minimize the occurrence of indeterminate results (i.e., discordant results when using at least two different rapid tests). It is often quite difficult for HIV counselors and health care providers to disclose such indeterminate results. In the context of interventions for prevention of mother-to-child transmission (PMTCT) of HIV-1 (which can require immediate decisions, notably during labor), medical staff need to know rapidly the HIV status of the woman from the laboratory in order to provide her, or not, antiretroviral (ARV) prophylaxis (5, 26, 27). The prolonged delay in the decision (by performing additional tests or by retesting women 14 days later) can be inappropriate in the clinical routine since women may deliver before obtaining definitive results.The aims of this study conducted among pregnant women from Burkina Faso (West Africa) with a low risk of early HIV-1 seroconversion were (i) to determine the prevalence rates of indeterminate results by using two rapid tests in a sequential algorithm, as recommended in Burkina Faso, and (ii) to assess, using additional tests, the biological significance of indeterminate results in order to define a more rational strategy at the individual and public health levels.(This work was presented in part at the 15th Conference on AIDS and STDs in Africa, Dakar, Senegal, 3 to 7 December 2008 [17].)     

From evaluating a Skilled Care Initiative in rural Burkina Faso to policy implications for safe motherhood in Africa

Evaluation findings from a particular setting need to be generalized into policy implications if they are to find widespread use. Skilled attendance at delivery is widely regarded as one of the most important intervention strategies for safe motherhood in low-resource settings, particularly in Africa, but implementations of such strategies are often not rigorously evaluated or interpreted into future policy. Initiative for Maternal Mortality Programme Assessment (Immpact) has applied a package of research-based monitoring and evaluation tools to assess the Family Care International Skilled Care Initiative in Ouargaye District, Burkina Faso. This evaluation research aimed to generate reliable, evidence-based policies for accelerating safe motherhood programmes in Burkina Faso and elsewhere in Africa. Five policy priorities were identified as representing real chances of improving the safety of motherhood: (1) enhancing national coverage of delivery by professionally skilled attendants; (2) to provide a network of 24-h basic emergency obstetric care within 5 km; (3) to have an effective referral system, equipped and resourced to undertake a reasonable number of Caesarean sections; (4) to promote community mobilization activities as a lever to increasing delivery care utilization; and (5) to implement strategies to remove financial barriers to delivery care. To meet Millennium Development Goal five by 2015, both supply and demand side constraints on the provision of quality maternity care have to be addressed, which in turn need greater political commitment and funding.     

Strengthening regulatory science in academia: STARS,an EU initiative to bridge the translational gap

Truly disruptive medicine innovation and new treatment paradigms tend to start in non-commercial research institutions. However, the lack of mutual understanding between medicine developers and regulators when it comes to medicine development significantly delays or even prevents the access of patients to these innovations. Here, we outline what regulatory-related barriers hamper the translational development of novel products or new treatment paradigms initiated in academia, and propose key steps towards improved regulatory dialogue among academia, funding bodies and regulatory authorities. Moreover, we briefly describe how the STARS (Strengthening Training of Academia in Regulatory Science) project aims to reach out to medicine innovators in academia to bridge the regulatory knowledge gap and enhance this dialogue to facilitate the implementation of academic research findings in clinical practice.     

Mouse Precision-Cut Liver Slices as an ex Vivo Model To Study Idiosyncratic Drug-Induced Liver Injury

Idiosyncratic drug-induced liver injury (IDILI) has been the top reason for withdrawing drugs from the market or for black box warnings. IDILI may arise from the interaction of a drug's reactive metabolite with a mild inflammation that renders the liver more sensitive to injury resulting in increased toxicity (inflammatory stress hypothesis). Aiming to develop a robust ex vivo screening method to study inflammatory stress-related IDILI mechanisms and to find biomarkers that can detect or predict IDILI, mouse precision-cut liver slices (mPCLS) were coincubated for 24 h with IDILI-related drugs and lipopolysaccharide. Lipopolysaccharide exacerbated ketoconazole (15 μM) and clozapine (45 μM) toxicity but not their non-IDILI-related comparators, voriconazole (1500 μM) and olanzapine (45 μM). However, the other IDILI-related drugs tested [diclofenac (200 μM), carbamazepine (400 μM), and troglitazone (30 μM)] did not cause synergistic toxicity with lipopolysaccharide after 24 h of incubation. Lipopolysaccharide further decreased the reduced glutathione levels caused by ketoconazole or clozapine in mPCLS after 24 h of incubation, which was not the case for the other drugs. Lipopolysaccharide significantly increased nitric oxide (NO), cytokine, and chemokine release into the mPCLS media, while the treatment with the drugs alone did not cause any substantial change. All seven drugs drastically reduced lipopolysaccharide-induced NO production. Interestingly, only ketoconazole and clozapine increased the lipopolysaccharide-induced granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) release. Pilot experiments showed that diclofenac and troglitazone, but not carbamazepine, demonstrated synergistic toxicity with lipopolysaccharide after a longer incubation of 48 h in mPCLS. In conclusion, we have developed an ex vivo model to detect inflammatory stress-related liver toxicity and identified ketoconazole, clozapine, troglitazone, and diclofenac as drugs that showed synergistic toxicity with lipopolysaccharide. Reduced glutathione, G-CSF, and GM-CSF were identified to be potential biomarkers for IDILI-inducing drugs mediated by inflammatory stress, and mPCLS appear to be a promising screening tool to further unravel the mechanism of IDILI.