Guiding the choice of informatics software and tools for lipidomics research applications

Progress in mass spectrometry lipidomics has led to a rapid proliferation of studies across biology and biomedicine. These generate extremely large raw datasets requiring sophisticated solutions to support automated data processing. To address this, numerous software tools have been developed and tailored for specific tasks. However, for researchers, deciding which approach best suits their application relies on ad hoc testing, which is inefficient and time consuming. Here we first review the data processing pipeline, summarizing the scope of available tools. Next, to support researchers, LIPID MAPS provides an interactive online portal listing open-access tools with a graphical user interface. This guides users towards appropriate solutions within major areas in data processing, including (1) lipid-oriented databases, (2) mass spectrometry data repositories, (3) analysis of targeted lipidomics datasets, (4) lipid identification and (5) quantification from untargeted lipidomics datasets, (6) statistical analysis and visualization, and (7) data integration solutions. Detailed descriptions of functions and requirements are provided to guide customized data analysis workflows.

Analytical and computational workflow for in-depth analysis of oxidized complex lipids in blood plasma

Lipids are a structurally diverse class of biomolecules which can undergo a variety of chemical modifications. Among them, lipid (per)oxidation attracts most of the attention due to its significance in the regulation of inflammation, cell proliferation and death programs. Despite their apparent regulatory significance, the molecular repertoire of oxidized lipids remains largely elusive as accurate annotation of lipid modifications is complicated by their low abundance and often unknown, biological context-dependent structural diversity. Here, we provide a workflow based on the combination of bioinformatics and LC-MS/MS technologies to support identification and relative quantification of oxidized complex lipids in a modification type- and position-specific manner. The developed methodology is used to identify epilipidomics signatures of lean and obese individuals with and without type 2 diabetes. The characteristic signature of lipid modifications in lean individuals, dominated by the presence of modified octadecanoid acyl chains in phospho- and neutral lipids, is drastically shifted towards lipid peroxidation-driven accumulation of oxidized eicosanoids, suggesting significant alteration of endocrine signalling by oxidized lipids in metabolic disorders.

Research Techniques Made Simple: Lipidomic Analysis in Skin Research

Although lipids are crucial molecules for cell structure, metabolism, and signaling in most organs, they have additional specific functions in the skin. Lipids are required for the maintenance and regulation of the epidermal barrier, physical properties of the skin, and defense against microbes. Analysis of the lipidome-the totality of lipids-is of similar complexity to those of proteomics or other omics, with lipid structures ranging from simple, linear, to highly complex structures. In addition, the ordering and chemical modifications of lipids have consequences on their biological function, especially in the skin. Recent advances in analytic capability (usually with mass spectrometry), bioinformatic processing, and integration with other dermatological big data have allowed researchers to increasingly understand the roles of specific lipid species in skin biology. In this paper, we review the techniques used to analyze skin lipidomics and epilipidomics.

AdipoAtlas: A reference lipidome for human white adipose tissue

Obesity, characterized by expansion and metabolic dysregulation of white adipose tissue (WAT), has reached pandemic proportions and acts as a primer for a wide range of metabolic disorders. Remodeling of WAT lipidome in obesity and associated comorbidities can explain disease etiology and provide valuable diagnostic and prognostic markers. To support understanding of WAT lipidome remodeling at the molecular level, we provide in-depth lipidomics profiling of human subcutaneous and visceral WAT of lean and obese individuals. We generate a human WAT reference lipidome by performing tissue-tailored preanalytical and analytical workflows, which allow accurate identification and semi-absolute quantification of 1,636 and 737 lipid molecular species, respectively. Deep lipidomic profiling allows identification of main lipid (sub)classes undergoing depot-/phenotype-specific remodeling. Previously unanticipated diversity of WAT ceramides is now uncovered. AdipoAtlas reference lipidome serves as a data-rich resource for the development of WAT-specific high-throughput methods and as a scaffold for systems medicine data integration.

Development and validation of a competency evaluation model for hospital infection prevention and control practitioners in the post-pandemic era: a mixed methods study

Background

During the coronavirus disease 2019 pandemic, the management of nosocomial infections became even more crucial. There is an urgent need to develop a competency model for healthcare practitioners to combat public health emergencies.

Aim

To determine practitioners' competency in hospital infection prevention and control measures.

Methods

A theoretical framework was developed based on a literature review, key informant interviews, the Delphi method and a questionnaire survey. These items were evaluated based on response rate, maximum score, minimum score and mean score. Factor analyses, both exploratory and confirmatory, were used to determine the structure of the competency model.

Results

The effective response rate for the questionnaire was 88.29%, and Cronbach's α-coefficient was 0.964. Factor analysis revealed a Kaiser–Meyer–Olkin score of 0.945. Bartlett's test gave a χ²-value of 10523.439 (df=435; P<0.001). After exploratory factor analysis, the five-factor model was retained, four items were deleted and a five-dimensional, 26-item scale was obtained. The new structure's confirmatory factor analysis revealed high goodness of fit (comparative fit index=0.921; Tucker–Lewis index=0.911; standardized root mean square residual=0.053; root mean square error of approximation=0.044).

Conclusion

The proposed scale is a useful tool to assess the competency of hospital infection prevention and control practitioners, which can help hospitals to improve infection prevention and control.

A Novel Technique for Redox Lipidomics Using Mass Spectrometry: Application on Vegetable Oils Used to Fry Potatoes

Vegetables oils, rich in polyunsaturated fatty acids, are vulnerable to oxidation during manufacturing, processing, and food preparation. Currently, individual oxidation products are not well characterized, and hence, the health impacts of these unique lipid species remain unknown. Here, we introduce an extensive oxidized lipidomics in silico tandem mass spectrometry library and integrate these libraries within a user-friendly software covering a comprehensive redox lipidomics workflow. We apply this workflow to olive, soy, and walnut cooking oil; comparing unheated oil, oil after deep frying potatoes, and oil after oven frying potatoes. We annotated over a thousand oxidized triglycerides across 273 features (many coeluted). This software was validated against traditional chemical assays of oxidation, known oxidized lipids in castor oil, synthesized standards, and an alternate software LPPtiger. Development of these new software programs for redox lipidomics opens the door to characterize health implications of individual oxidation products.

Interpreting the lipidome: bioinformatic approaches to embrace the complexity

BACKGROUND

Improvements in mass spectrometry (MS) technologies coupled with bioinformatics developments have allowed considerable advancement in the measurement and interpretation of lipidomics data in recent years. Since research areas employing lipidomics are rapidly increasing, there is a great need for bioinformatic tools that capture and utilize the complexity of the data. Currently, the diversity and complexity within the lipidome is often concealed by summing over or averaging individual lipids up to (sub)class-based descriptors, losing valuable information about biological function and interactions with other distinct lipids molecules, proteins and/or metabolites.

AIM OF REVIEW

To address this gap in knowledge, novel bioinformatics methods are needed to improve identification, quantification, integration and interpretation of lipidomics data. The purpose of this mini-review is to summarize exemplary methods to explore the complexity of the lipidome.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Here we describe six approaches that capture three core focus areas for lipidomics: (1) lipidome annotation including a resolvable database identifier, (2) interpretation via pathway- and enrichment-based methods, and (3) understanding complex interactions to emphasize specific steps in the analytical process and highlight challenges in analyses associated with the complexity of lipidome data.

BioPAN: a web-based tool to explore mammalian lipidome metabolic pathways on LIPID MAPS

Lipidomics increasingly describes the quantification using mass spectrometry of all lipids present in a biological sample.  As the power of lipidomics protocols increase, thousands of lipid molecular species from multiple categories can now be profiled in a single experiment.  Observed changes due to biological differences often encompass large numbers of structurally-related lipids, with these being regulated by enzymes from well-known metabolic pathways.  As lipidomics datasets increase in complexity, the interpretation of their results becomes more challenging.  BioPAN addresses this by enabling the researcher to visualise quantitative lipidomics data in the context of known biosynthetic pathways.  BioPAN provides a list of genes, which could be involved in the activation or suppression of enzymes catalysing lipid metabolism in mammalian tissues.

BioPAN: a web-based tool to explore mammalian lipidome metabolic pathways on LIPID MAPS

Lipidomics increasingly describes the quantification using mass spectrometry of all lipids present in a biological sample.  As the power of lipidomics protocols increase, thousands of lipid molecular species from multiple categories can now be profiled in a single experiment.  Observed changes due to biological differences often encompass large numbers of structurally-related lipids, with these being regulated by enzymes from well-known metabolic pathways.  As lipidomics datasets increase in complexity, the interpretation of their results becomes more challenging.  BioPAN addresses this by enabling the researcher to visualise quantitative lipidomics data in the context of known biosynthetic pathways.  BioPAN provides a list of genes, which could be involved in the activation or suppression of enzymes catalysing lipid metabolism in mammalian tissues.

Super-factors associated with transmission of occupational COVID-19 infection among healthcare staff in Wuhan, China

BACKGROUND

Globally, there have been many cases of coronavirus disease 2019 (COVID-19) among medical staff; however, the main factors associated with the infection are not well understood.

AIM

To identify the super-factors causing COVID-19 infection in medical staff in China.

METHODS

A cross-sectional study was conducted between January 1st and February 30th, 2020, in which front-line members of medical staff who took part in the care and treatment of patients with COVID-19 were enrolled. Epidemiological and demographic data between infected and uninfected groups were collected and compared. Social network analysis (SNA) was used to establish socio-metric social links between influencing factors.

FINDINGS

A total of 92 medical staff were enrolled. In all participant groups, the super-factor identified by the network was wearing a medical protective mask or surgical mask correctly (degree: 572; closeness: 25; betweenness centrality: 3.23). Touching the cheek, nose, and mouth while working was the super-factor in the infected group. This was the biggest node in the network and had the strongest influence (degree: 370; closeness: 29; betweenness centrality: 0.37). Self-protection score was the super-factor in the uninfected group but was the isolated factor in the infected group (degree: 201; closeness: 28; betweenness centrality: 5.64). For family members, the exposure history to Huanan Seafood Wholesale Market and the contact history to wild animals were two isolated nodes.

CONCLUSION

High self-protection score was the main factor that prevented medical staff from contracting COVID-19 infection. The main factor contributing to COVID-19 infections among medical staff was touching the cheek, nose, and mouth while working.

Evaluation of air oxidized PAPC: A multi laboratory study by LC-MS/MS

Oxidized LDL (oxLDL) has been shown to play a crucial role in the onset and development of cardiovascular disorders. The study of oxLDL, as an initiator of inflammatory cascades, led to the discovery of a variety of oxidized phospholipids (oxPLs) responsible for pro-inflammatory actions. Oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (PAPC) is frequently used by the scientific community as a representative oxPL mixture to study the biological effects of oxidized lipids, due to the high abundance of PAPC in human tissues and the biological activities of oxidized arachidonic acids derivatives. Most studies focusing on oxPAPC effects rely on in-house prepared mixtures of oxidized species obtained by exposing PAPC to air oxidation. Here, we described a multi-laboratory evaluation of the compounds in oxPAPC by LC-MS/MS, focusing on the identification and relative quantification of the lipid peroxidation products (LPPs) formed. PAPC was air-oxidized in four laboratories using the same protocol for 0, 48, and 72 h. It was possible to identify 55 different LPPs with unique elemental composition and characterize different structural isomeric species within these. The study showed good intra-sample reproducibility and similar qualitative patterns of oxidation, as the most abundant LPPs were essentially the same between the four laboratories. However, there were substantial differences in the extent of oxidation, i.e. the amount of LPPs relative to unmodified PAPC, at specific time points. This shows the importance of characterizing air-oxidized PAPC preparations before using them for testing biological effects of oxidized lipids, and may explain some variability of effects reported in the literature.

Computational solutions in redox lipidomics - Current strategies and future perspectives

The high chemical diversity of lipids allows them to perform multiple biological functions ranging from serving as structural building blocks of biological membranes to regulation of metabolism and signal transduction. In addition to the native lipidome, lipid species derived from enzymatic and non-enzymatic modifications (the epilipidome) make the overall picture even more complex, as their functions are still largely unknown. Oxidized lipids represent the fraction of epilipidome which has attracted high scientific attention due to their apparent involvement in the onset and development of numerous human disorders. Development of high-throughput analytical methods such as liquid chromatography coupled on-line to mass spectrometry provides the possibility to address epilipidome diversity in complex biological samples. However, the main bottleneck of redox lipidomics, the branch of lipidomics dealing with the characterization of oxidized lipids, remains the lack of optimal computational tools for robust, accurate and specific identification of already discovered and yet unknown modified lipids. Here we discuss the main principles of high-throughput identification of lipids and their modified forms and review the main software tools currently available in redox lipidomics. Different levels of confidence for software assisted identification of redox lipidome are defined and necessary steps toward optimal computational solutions are proposed.

Monitoring of optical emissions in laser cladding of 316L stainless steel

Laser cladding is so complex that small disturbances may cause defects. Developing on-line monitoring technology for laser cladding is thus a priority task. Compared with expensive spectrometers and high-speed cameras, an economical optical sensing system based on two different photodiodes was established to optimize laser parameters and help monitor abnormal working conditions. In order to find optimal parameters, a series of experiments was carried out under different operating parameters such as laser power, scanning speed, and powder feeding rate. A practical rule is summarized to optimize process parameters by analyzing the time domain characteristics of the optical signal. Several experiments under different working conditions were performed to detect abnormal working conditions. Not only can an abnormal situation be recognized, but its type can also be distinguished by analyzing optical signals in the time and frequency domains. The optical sensing system provides a better understanding and accurate evaluation of laser cladding.

Oxidative modification of skin lipids by cold atmospheric plasma (CAP): A standardizable approach using RP-LC/MS2 and DI-ESI/MS2

Cold atmospheric plasma (CAP) is an emerging source for the locally defined delivery of reactive species, and its clinical potential has been identified in the control of inflammatory processes, such as acute and chronic wounds, or cancerous lesions. Lipids, due to their localization and chemical structure as ideal targets for oxidative species, are relevant modifiers of physiological processes. Human forehead lipids collected on a target were treated by an argon plasma jet and immediately analyzed by direct-infusion high-resolution tandem mass spectrometry (DI-MS²) or liquid chromatography-tandem MS (RP-LC/MS²). Subsequent data analysis was performed by LipidHunter (University of Leipzig), LipidXplorer (Max Planck Institute of Molecular Cell Biology and Genetics, Dresden), and LipidSearch (Thermo Scientific). With either MS method, all major lipid classes of sebum lipids were detected. Significant differences regarding triacylglycerols (predominantly identified in RP-LC/MS²) and ceramides (predominantly identified in DI-MS²) indicate experimental- or approach-inherent distinctions. A CAP-driven oxidation of triacyclglycerols, ceramides, and cholesteryl esters was detected such as truncations and hydroperoxylations, but at a significantly lower extent than expected. Scavenging of reactive species due to naturally present antioxidants in the samples and the absence of a liquid interphase to allow reactive species deposition by the CAP will have contributed to the limited amount of oxidation products observed. In addition, limitations of the software's capability of identifying unexpected oxidized lipids potentially led to an underestimation of the CAP impact on skin lipids, indicating a need for further software development. With respect to the clinical application of CAP, the result indicates that intact skin with its sebum/epidermal lipid overlay is well protected and that moderate treatment will yield limited (if any) functional consequences in the dermal tissue.

[One case of pyoderma gangrenosum in the lower limbs in Tibetan Plateau treated with vacuum sealing drainage combined with irrigation of oxygen loaded fluid]

A 54 years old male patient with chronic leg ulcers was admitted in our hospital in November 2017. He was diagnosed as pyoderma gangrenosum by the pathological examination. Then the wound was treated with simple vacuum sealing drainage combined with irrigation of oxygen loaded fluid. This therapy overcame the shortage of hypoxia in the Tibetan Plateau on wound healing, resulting in a better wound healing. The patient was eventually cured and discharged from hospital.

Erythropoietin Ameliorates Lung Injury by Accelerating Pulmonary Endothelium Cell Proliferation via Janus Kinase-Signal Transducer and Activator of Transcription 3 Pathway After Kidney Ischemia and Reperfusion Injury

BACKGROUND/AIMS

Kidney ischemia and reperfusion injury could cause microvascular barrier dysfunction, lung inflammatory cascades activation, and programmed cell death of pulmonary endothelium, leading to acute lung injury. Our study aimed at determining whether erythropoietin (EPO) can ameliorate lung dysfunction following renal ischemia and reperfusion (IR) injury and explored the underlying mechanisms.

METHODS

In vivo, C57BL/6 mice received EPO (6000 U/kg) before right renal vascular pedicles clamping for 30 minutes, followed by 24 hours of reperfusion. The lung histopathologic changes and inflammatory cytokines expression were assessed. In vitro, cultured human umbilical vein endothelial cells were treated with EPO, and apoptosis rate, proliferation capacity, and phosphorylation status of the Janus kinase-signal transducer and activator of transcription 3 (Jak-STAT3) pathway were measured respectively in the presence or absence of lipopolysaccharide stimulation.

RESULTS

In vivo, EPO remarkably attenuated pulmonary interstitial and alveolar epithelial edema caused by renal IR injury. In vitro, the proliferation capacity of human umbilical vein endothelial cells was significantly increased under EPO stimulation, which correlated with changes in Jak-STAT3 signaling.

CONCLUSION

Our data indicated that EPO is able to ameliorate acute lung tissue damage induced by renal IR, and at least in part, via the Jak-STAT3 pathway.

A novel FGFR1-binding peptide attenuates the degeneration of articular cartilage in adult mice

OBJECTIVE

We previously reported that genetic ablation of (Fibroblast Growth Factors Receptors) FGFR1 in knee cartilage attenuates the degeneration of articular cartilage in adult mice, which suggests that FGFR1 is a potential targeting molecule for osteoarthritis (OA). Here, we identified R1-P1, an inhibitory peptide for FGFR1 and investigated its effect on the pathogenesis of OA in mice induced by destabilization of medial meniscus (DMM).

DESIGN

Binding ability between R1-P1 and FGFR1 protein was evaluated by enzyme-linked immuno sorbent assay (ELISA) and molecular docking. Alterations in cartilage were evaluated histologically. The expression levels of molecules associated with articular cartilage homeostasis and FGFR1 signaling were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting and immunohistochemistry (IHC). The chondrocyte apoptosis was detected by terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) assay.

RESULTS

R1-P1 had highly binding affinities to human FGFR1 protein, and efficiently inhibited extracellular signal-regulated kinase (ERK)1/2 pathway in mouse primary chondrocytes. In addition, R1-P1 attenuated the IL-1β induced significant loss of proteoglycan in full-thickness cartilage tissue from human femur head. Moreover, this peptide can significantly restore the IL-1β mediated loss of proteoglycan and type II collagen (Col II) and attenuate the expression of matrix metalloproteinase-13 (MMP13) in mouse primary chondrocytes. Finally, intra-articular injection of R1-P1 remarkably attenuated the loss of proteoglycan and the destruction of articular cartilage and decreased the expressions of extracellular matrix (ECM) degrading enzymes and apoptosis in articular chondrocytes of mice underwent DMM surgery.

CONCLUSIONS

R1-P1, a novel inhibitory peptide for FGFR1, attenuates the degeneration of articular cartilage in adult mice, which is a potential leading molecule for the treatment of OA.

A novel role for NUPR1 in the keratinocyte stress response to UV oxidized phospholipids

Ultraviolet light is the dominant environmental oxidative skin stressor and a major skin aging factor. We studied which oxidized phospholipid (OxPL) mediators would be generated in primary human keratinocytes (KC) upon exposure to ultraviolet A light (UVA) and investigated the contribution of OxPL to UVA responses. Mass spectrometric analysis immediately or 24 h post UV stress revealed significant changes in abundance of 173 and 84 lipid species, respectively. We identified known and novel lipid species including known bioactive and also potentially reactive carbonyl containing species. We found indication for selective metabolism and degradation of selected reactive lipids. Exposure to both UVA and to in vitro UVA - oxidized phospholipids activated, on transcriptome and proteome level, NRF2/antioxidant response signaling, lipid metabolizing enzyme expression and unfolded protein response (UPR) signaling. We identified NUPR1 as an upstream regulator of UVA/OxPL transcriptional stress responses and found this protein to be expressed in the epidermis. Silencing of NUPR1 resulted in augmented expression of antioxidant and lipid detoxification genes and disturbed the cell cycle, making it a potential key factor in skin reactive oxygen species (ROS) responses intimately involved in aging and pathology.

Analytical indicators to characterize Particulate Organic Matter (POM) and its evolution in French Vertical Flow Constructed Wetlands (VFCWs)

The design of French VFCWs leads to the formation of a sludge layer at the surface of the first filters due to the retention of suspended solids from the percolation of unsettled wastewater. This layer plays a major role in the system but still little is known on its characteristics and evolutions. In this study, suspended solids and sludge deposits sampled from two French VFCW plants were analyzed by different methods in the objective to assess the evolution of particulate organic matter (POM) along the treatment chain and within the sludge layer, and identify relevant analytical indicators of these phenomena. The treatment chain included an aerobic trickling filter followed by FeCl₃ injection and two successive stages of filters. Thermal analyses showed that OM contents of suspended solids decreased along the treatment chain. POM in inflow suspended solids was predominantly composed of reactive, biodegradable compounds which were partly hydrolyzed and mineralized notably at the trickling filter stage. 3D fluorescence spectra collected from aqueous POM extracts confirmed the evolution of organic matter from low-molecular reactive compounds to more complex and stable structures such as humic-like substances. FTIR confirmed the mineralization of POM's reactive constituents along the treatment chain by the decrease in the intensities of the characteristics bands of aliphatic compounds or proteins, and its humification in the sludge deposits through the relative increase of the bands at 1634cm^-1 (v_C=O) and 1238cm^-1 (δ_C=O and/or δ_OH). Isotopic ratios δ²H/¹H and δ¹⁵N/¹⁴N were found to be good indicators of POM evolutions. The higher values of δ²H/¹H and δ¹⁵N/¹⁴N ratios measured in sludge deposits as compared to inflow suspended solids were related to POM humification and to microbial processes of POM hydrolysis and mineralization, respectively.

LPPtiger software for lipidome-specific prediction and identification of oxidized phospholipids from LC-MS datasets

Oxidized phospholipids (oxPLs) have been recently recognized as important mediators of various and often controversial cellular functions and stress responses. Due to the low concentrations in vivo, oxPL detection is mostly performed by targeted mass spectrometry. Although significantly improving the sensitivity, this approach does not provide a comprehensive view on oxPLs required for understanding oxPL functional activities. While capable of providing information on the diversity of oxPLs, the main challenge of untargeted lipidomics is the absence of bioinformatics tools to support high-throughput identification of previously unconsidered, oxidized lipids. Here, we present LPPtiger, an open-source software tool for oxPL identification from data-dependent LC-MS datasets. LPPtiger combines three unique algorithms to predict oxidized lipidome, generate oxPL spectra libraries, and identify oxPLs from tandem MS data using parallel processing and a multi-scoring identification workflow.

LipidHunter Identifies Phospholipids by High-Throughput Processing of LC-MS and Shotgun Lipidomics Datasets

Lipids are dynamic constituents of biological systems, rapidly responding to any changes in physiological conditions. Thus, there is a large interest in lipid-derived markers for diagnostic and prognostic applications, especially in translational and systems medicine research. As lipid identification remains a bottleneck of modern untargeted lipidomics, we developed LipidHunter, a new open source software for the high-throughput identification of phospholipids in data acquired by LC-MS and shotgun experiments. LipidHunter resembles a workflow of manual spectra annotation. Lipid identification is based on MS/MS data analysis in accordance with defined fragmentation rules for each phospholipid (PL) class. The software tool matches product and neutral loss signals obtained by collision-induced dissociation to a user-defined white list of fatty acid residues and PL class-specific fragments. The identified signals are tested against elemental composition and bulk identification provided via LIPID MAPS search. Furthermore, LipidHunter provides information-rich tabular and graphical reports allowing to trace back key identification steps and perform data quality control. Thereby, 202 discrete lipid species were identified in lipid extracts from rat primary cardiomyocytes treated with a peroxynitrite donor. Their relative quantification allowed the monitoring of dynamic reconfiguration of the cellular lipidome in response to mild nitroxidative stress. LipidHunter is available free for download at https://bitbucket.org/SysMedOs/lipidhunter .

Meta-analysis of hypertension and osteoporotic fracture risk in women and men

The present meta-analysis synthesized evidence from 10 articles encompassing 28 independent studies to verify the association between hypertension and osteoporotic fracture risk in women and men. Our results indicate that the risk of osteoporotic fracture among individuals with hypertension was higher than that among individuals without hypertension.

INTRODUCTION

Epidemiological studies have suggested that hypertension is related to osteoporotic fracture. However, discrepancies exist in the reported findings. In this study, a systematic review of relevant published articles was conducted to verify the association between hypertension and osteoporotic fracture risk in women and men.

METHODS

PubMed (1953_October 5th, 2016) and Embase (1974_October 5th, 2016) were systematically searched for relevant articles. Odds ratios (ORs) and confidence intervals (CIs) were derived using random effect models. Categorical, subgroup, heterogeneity, publication bias, and meta-regression analyses were conducted.

RESULTS

We analyzed 10 articles encompassing 28 independent studies, 1,430,431 participants, and 148,048 osteoporotic fracture cases. The risk of osteoporotic fracture among individuals with hypertension was higher (pooled OR = 1.33, 95% CI 1.25-1.40; I ² = 72.3%, P < 0.001) than that among individuals without hypertension. The association between hypertension and fracture risk was slightly stronger in women (pooled OR = 1.52, 95% CI 1.30-1.79) than in men (pooled OR = 1.35, 95% CI 1.26-1.44). Studies conducted in Asia revealed results that were consistent with those of studies performed in Europe.

CONCLUSIONS

Hypertension is associated with osteoporotic fracture risk. However, the biological mechanisms underlying the effect of hypertension on osteoporotic fracture remain to be elucidated.

Efficiency, effectiveness and treatment stability of clear aligners: A systematic review and meta-analysis

OBJECTIVES

The objective of this study was to perform a systematic review of the orthodontic literature with regard to efficiency, effectiveness and stability of treatment outcome with clear aligners compared with treatment with conventional brackets.

METHODS

An electronic search without time or language restrictions was undertaken in October 2014 in the following electronic databases: Google Scholar, the Cochrane Oral Health Group's Trials Register, Scopus, CENTRAL, MEDLINE via OVID, EMBASE via OVID and Web of Science. We also searched the reference lists of relevant articles. Quality assessment of the included articles was performed. Two authors were responsible for study selection, validity assessment and data extraction.

RESULTS

Four controlled clinical trials including a total of 252 participants satisfied the inclusion criteria. We grouped the trials into four main comparisons. One randomized controlled trial was classified as level 1B evidence, and three cohort studies were classified as level 2B evidence. Clear aligners appear to have a significant advantage with regard to chair time and treatment duration in mild-to-moderate cases based on several cross-sectional studies. No other differences in stability and occlusal characteristics after treatment were found between the two systems.

CONCLUSIONS

Despite claims about the effectiveness of clear aligners, evidence is generally lacking. Shortened treatment duration and chair time in mild-to-moderate cases appear to be the only significant effectiveness of clear aligners over conventional systems that are supported by the current evidence.

Novel stent in the palliation of malignant esophageal strictures: a retrospective study

The placement of metal stents is often used as a palliative treatment for malignant esophageal stenosis. We designed a novel stent that has been used clinically since 2011, and we therefore performed a retrospective study to compare the therapeutic effects of this novel metal stent to a conventional partially covered metal stent in patients with malignant esophageal strictures. The records of 201 consecutive patients who underwent placement of either the conventional partially covered metal stents (Group A, n = 92) or the new metal stents (Group B, n = 109) in the Endoscopy Center of General Hospital of Chengdu Military Command from October 2008 to March 2013 were reviewed. The median dysphagia score significantly improved in both groups 1 week following stent placement (P < 0.001). No significant differences were observed in success rate (P = 0.910) or the complication rate (P = 0.426) between groups. Six months after stent placement, recurrent dysphagia due to stent migration, tissue ingrowth or overgrowth or food obstruction occurred in 45% and 29% of patients in the conventional stent and new stent groups, respectively. The results of this retrospective study indicate that the new modified self-expandable metal stents (SEMS) is at least as safe and effective as the conventional partially covered SEMS in treatment of malignant esophageal strictures.

[Direct anterior approach versus posterolateral approach for total hip arthroplasty in the lateral decubitus position]

Objective: To compare the clinical efficacy of the direct anterior approach (DAA) and the posterolateral approach (PLA) for total hip arthroplasty (THA) in the lateral decubitus position. Methods: From July to December, 2014, 104 patients randomly divided into two equal groups of the DAA group and the PLA group underwent unilateral primary THA procedures.All procedures were performed by the same surgeon in the Department of Orthopaedics, the Affiliated Anhui Provincial Hospital of Anhui Medical University.General data, perioperative index, postoperative function and radiological evaluation were recorded and statistically analyzed. Results: The patients had an average follow-up of 14 (range, 10-16) months.No significant differences were detected with respect to the operation time, incision length, preoperative Hb concentration and transfusion rate between two groups (P> 0.05 for all comparisons). However, there were significant differences associated with the intraoperative bleeding, postoperative drainage and postoperative Hb concentration in the two groups(P<0.05 for all comparisons). The DAA group showed significant superior outcomes compared with the PLA group in the Harris hip scores [(83.6±7.1) vs (79.8±6.6), P<0.05], WOMAC[ (28.9±6.1) vs (36.1±6.9), P<0.001], and VAS pain scores[ (2.2±0.9) vs (2.9±1.1), P<0.05]at 1 month after surgery. No differences were seen between the study groups in the evaluation of radiography and the incidence of adverse event (P> 0.05 for all comparisons). Conclusions: Compared with the posterolateral approach, the present study shows the exciting results in patients underwent the DAA THA in the lateral decubitus position at early follow-up.The advantages of THA using the DAA include less operative trauma, alleviation of postoperative pain, and faster postoperative rehabilitation. It is a safe, reliable and effective surgery approach.

Upregulated microRNA-301a in osteosarcoma promotes tumor progression by targeting CDC14A

MicroRNAs (miRs) are associated with tumor progression in various cancers, such as gastric and hepatic carcinomas, and lung cancer. miR-301a is overexpressed and displays oncogenic activity in cancers. We investigated the biological involvement of miR-301a in osteosarcoma (OS). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to analyze expression levels of miR-301a in 24 OS and matched adjacent non-tumor tissues. A miR-301a mimic was transferred into OS cell lines U-2 OS and MG-63 to upregulate miR-301a. The effects of miR-301a were investigated by examining cell proliferation, migration, and the cell cycle. The miR-301 target was predicted by TargetScan and confirmed by western blotting and qRT-PCR. The expression of miR-301a was significantly higher in OS tissues compared with the matched adjacent non-tumor tissues (0.959 ± 0.39 vs 3.9516 ± 1.18). Upregulated miR-301a significantly increased proliferation at 48 and 72 h compared to the negative control (U-2 OS: 2.11 ± 0.21 vs 2.88 ± 0.24; 2.70 ± 0.26 vs 3.71 ± 0.24; MG-63: 2.19 ± 0.20 vs 3.19 ± 0.22; 3.1 ± 0.25 vs 4.01 ± 0.27) and migration capability (U-2 OS: 100 ± 20.19 vs 150.68 ± 32.83; MG-63: 100 ± 17.20 vs 133.35 ± 26.26), and decreased apoptosis in both U-2 OS (10.87 ± 2.53 vs 4.01 ± 2.23) and MG-63 (15.26 ± 2.15 vs 8.25 ± 3.07). The cell cycle studies revealed that miR-301a caused an increase of the G2 population in U-2 OS (38.6 ± 6.58 vs 47.2 ± 7.27) and MG-63 (44.01 ± 5.28 vs 57.9 ± 4.25). Additional experiments indicated that CDC14A was upregulated by miR-301a (0.63 ± 0.06 vs 0.98 ± 0.06; 1.49 ± 0.25 vs 2.99 ± 0.14). Overexpressed miR-301a may increase CDC14A expression and promote cell proliferation and migration in OS cells. Therefore, miR- 301a may be useful for osteosarcoma diagnosis and therapy.

Inflammatory dentigerous cyst of mandibular first premolar associated with endodontically treated primary first molar: a rare case report

AIM

Inflammatory dentigerous cysts usually occur in the mixed dentition. It has been reported that inflammatory lesions from the root area of a deciduous tooth bring about the development of dentigerous cysts around the unerupted permanent tooth bud. Endodontic treatment is a common and successful procedure for periapical inflammation in children. An inflammatory dentigerous cyst can occur in conjunction with endodontically treated primary tooth.

CASE REPORT

This article reports a case of 6 years and 6 months old boy, with a single, well-defined, unilocular, radiolucent area enclosing the first right unerupted mandibular premolar, accidentally discovered on the panoramic radiograph. The first right primary molar had received a root canal treatment 18 months prior. Clinical findings combined with radiographic and microscopic examinations confirmed the diagnosis of inflammatory dentigerous cyst. As treatment, enucleation of the cyst with removal of the involved permanent tooth was chosen and a removable partial denture was supplied to the patient after surgery. The 5-year follow-up revealed good healing of the bony lesion and displaced teeth.

CONCLUSION

This case presented a severe and rare complication of endodontically treated primary tooth, and the recommendation includes: (1) early diagnosis of dentigerous cysts, which is essential to prevent extensive treatment; (2) more information on the adverse side effects of an endodontic treatment should be given to patients and parents; (3) patients should be informed about the importance of follow-ups and radiographic follow-up should be routinised.

Fluorescence labeling of carbonylated lipids and proteins in cells using coumarin-hydrazide

Carbonylation is a generic term which refers to reactive carbonyl groups present in biomolecules due to oxidative reactions induced by reactive oxygen species. Carbonylated proteins, lipids and nucleic acids have been intensively studied and often associated with onset or progression of oxidative stress related disorders. In order to reveal underlying carbonylation pathways and biological relevance, it is crucial to study their intracellular formation and spatial distribution. Carbonylated species are usually identified and quantified in cell lysates and body fluids after derivatization using specific chemical probes. However, spatial cellular and tissue distribution have been less often investigated. Here, we report coumarin-hydrazide, a fluorescent chemical probe for time- and cost-efficient labeling of cellular carbonyls followed by fluorescence microscopy to evaluate their intracellular formation both in time and space. The specificity of coumarin-hydrazide was confirmed in time- and dose-dependent experiments using human primary fibroblasts stressed with paraquat and compared with conventional DNPH-based immunocytochemistry. Both techniques stained carbonylated species accumulated in cytoplasm with strong perinuclear clustering. Using a complimentary array of analytical methods specificity of coumarin-hydrazide probe towards both protein- and lipid-bound carbonyls has been shown. Additionally, co-distribution of carbonylated species and oxidized phospholipids was demonstrated.

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Coumarin-hydrazide (CHH) chemical probe was used to label cellular carbonyls.

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CHH fluorescence microscopy allowed to monitor protein and lipid carbonyl distribution.

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CHH specificity towards protein- and lipid-bound carbonyls was demonstrated.

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CHH labeling and DNPH immunocytochemistry for microscopy imaging were compared.

Steatosis-induced proteins adducts with lipid peroxidation products and nuclear electrophilic stress in hepatocytes

Accumulating evidence suggests that fatty livers are particularly more susceptible to several pathological conditions, including hepatic inflammation, cirrhosis and liver cancer. However the exact mechanism of such susceptibility is still largely obscure. The current study aimed to elucidate the effect of hepatocytes lipid accumulation on the nuclear electrophilic stress. Accumulation of intracellular lipids was significantly increased in HepG2 cells incubated with fatty acid (FA) complex (1 mM, 2:1 oleic and palmitic acids). In FA-treated cells, lipid droplets were localized around the nucleus and seemed to induce mechanical force, leading to the disruption of the nucleus morphology. Level of reactive oxygen species (ROS) was significantly increased in FA-loaded cells and was further augmented by treatment with moderate stressor (CoCl₂). Increased ROS resulted in formation of reactive carbonyls (aldehydes and ketones, derived from lipid peroxidation) with a strong perinuclear accumulation. Mass-spectroscopy analysis indicated that lipid accumulation per-se can results in modification of nuclear protein by reactive lipid peroxidation products (oxoLPP). 235 Modified proteins involved in transcription regulation, splicing, protein synthesis and degradation, DNA repair and lipid metabolism were identified uniquely in FA-treated cells. These findings suggest that steatosis can affect nuclear redox state, and induce modifications of nuclear proteins by reactive oxoLPP accumulated in the perinuclear space upon FA-treatment.

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Effects of fatty acids on modification of nuclear proteins in hepatocytes was studied.

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Lipid accumulation was associated with abnormal nuclear morphology.

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Lipid accumulation promoted mitochondrial activity and enhanced ROS generation.

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Nuclear proteins were modified by lipid peroxidation products.

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Data suggest nuclear stress as a mechanism for fatty liver disease progression.

Protein and lipid carbonylation in cellular model of nitrosative stress: mass spectrometry, biochemistry and microscopy study

Within the wide range of oxidative modifications, "carbonylation" formed by the incorporation of aldehyde/keto groups, is commonly studied due to its role in cell physiology and as prospective biomarkers for numerous disorders. Despite close biochemical and physiological links between protein and lipid carbonylation, these two types of modifications are rarely addressed simultaneously in a single study. In nitrosative stress cell model we investigated levels of protein and lipid carbonylation and addressed the main modified species by combining LC-MS, biochemical, and microscopy studies. The influence of nitrosative stress on carbonylation of proteins and lipids was investigated for primary cardiomyocytes treated with SIN-1 for different time intervals. Lipid carbonylation was quantified by RPC-ESI-MS/MS. The results demonstrate dynamic generation, degradation and adduct formations of 25 different species including alkanals, alkenals, alkadienals, alkatrienals and oxo-carboxylic acids. Several new PL-bound aldehydes were present exclusively after a long incubation period. Carbonylated proteins were identified after aldehyde reactive probe derivatization, affinity enrichment and RPC-ESI-MS/MS. More than 200 proteins were identified and evaluated by systems biology to deduce the biological significance of the protein modifications. The protein carbonylation degree was verified using oxyblot and correlated with changes in 20S/26S proteasome activities. Furthermore, a new fluorescence microscopy based technique to stain carbonylated biomolecules was developed and compared with conventional DNPH-based immunocytochemistry. Subcellular localization of carbonylated species was investigated using mitochondrial and ER-specific co-localization experiments. Thus, the combination of lipidomics, proteomics, biochemical techniques, and microscopy imaging revealed a complex molecular pattern of "carbonylation stress" in the studied nitrosative stress cell model.

The novel BH-3 mimetic apogossypolone induces Beclin-1- and ROS-mediated autophagy in human hepatocellular carcinoma [corrected] cells

Apogossypolone (ApoG2), a novel derivative of gossypol, exhibits superior antitumor activity in Bcl-2 transgenic mice, and induces autophagy in several cancer cells. However, the detailed mechanisms are not well known. In the present study, we showed that ApoG2 induced autophagy through Beclin-1- and reactive oxygen species (ROS)-dependent manners in human hepatocellular carcinoma (HCC) cells. Incubating the HCC cell with ApoG2 abrogated the interaction of Beclin-1 and Bcl-2/xL, stimulated ROS generation, increased phosphorylation of ERK and JNK, and HMGB1 translocation from the nucleus to cytoplasm while suppressing mTOR. Moreover, inhibition of the ROS-mediated autophagy by antioxidant N-acetyl-cysteine (NAC) potentiates ApoG2-induced apoptosis and cell killing. Our results show that ApoG2 induced protective autophagy in HCC cells, partly due to ROS generation, suggesting that antioxidant may serve as a potential chemosensitizer to enhance cancer cell death through blocking ApoG2-stimulated autophagy. Our novel insights may facilitate the rational design of clinical trials for Bcl-2-targeted cancer therapy.