Metabolomics as a potential new approach for investigating human reproductive disorders

Metabolomic profiling of human semen in patients with oligospermia using high performance liquid chromatography-tandem mass spectrometry

Male infertility is one of the most common reproductive dysfunctions. Despite oligospermia being a cause of infertility, few studies have been conducted on it. This study aimed to investigate differences in semen metabolic patterns in patients with oligospermia and to identify potential biomarkers associated with oligospermia. Semen samples from oligospermia patients (20 cases) and healthy controls (20 cases) were detected by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and 72 and 89 metabolites were identified as potential markers in positive and negative ion modes, respectively. In addition, the results identified multiple metabolic pathways in patients with oligospermia, such as glycine serine and threonine metabolism, Synthesis and degradation of ketone bodies, Valine, leucine, and isoleucine degradation. These results described unique metabolic characteristics of semen in patients with oligospermia and provided novel insights into the mechanism of the semen disorder.

Nuclear Magnetic Resonance (NMR) Metabolomics: Current Applications in Equine Health Assessment

Metabolomics can allow for the comprehensive identification of metabolites within biological systems, at given time points, in physiological and pathological conditions. In the last few years, metabolomic analysis has gained popularity both in human and in veterinary medicine, showing great potential for novel applications in clinical activity. The aim of applying metabolomics in clinical practice is understanding the mechanisms underlying pathological conditions and the influence of certain stimuli (i.e., drugs, nutrition, exercise) on body systems, in the attempt of identifying biomarkers that can help in the diagnosis of diseases. Proton Nuclear Magnetic Resonance spectroscopy (1H-NMR) is well tailored to be used as an analytical platform for metabolites' detection at the base of metabolomics studies, due to minimal sample preparation and high reproducibility. In this mini-review article, the scientific production of NMR metabolomic applications to equine medicine is examined. The research works are very different in methodology and difficult to compare. Studies are mainly focused on exercise, reproduction, and nutrition, other than respiratory and musculoskeletal diseases. The available information on this topic is still scant, but a greater collection of data could allow researchers to define new reliable markers to be used in clinical practice for diagnostic and therapeutical purposes.

Metabolomics in hepatocellular carcinoma: From biomarker discovery to precision medicine

Hepatocellular carcinoma (HCC) remains a global health burden, and is mostly diagnosed at late and advanced stages. Currently, limited and insensitive diagnostic modalities continue to be the bottleneck of effective and tailored therapy for HCC patients. Moreover, the complex reprogramming of metabolic patterns during HCC initiation and progression has been obstructing the precision medicine in clinical practice. As a noninvasive and global screening approach, metabolomics serves as a powerful tool to dynamically monitor metabolic patterns and identify promising metabolite biomarkers, therefore holds a great potential for the development of tailored therapy for HCC patients. In this review, we summarize the recent advances in HCC metabolomics studies, including metabolic alterations associated with HCC progression, as well as novel metabolite biomarkers for HCC diagnosis, monitor, and prognostic evaluation. Moreover, we highlight the application of multi-omics strategies containing metabolomics in biomarker discovery for HCC. Notably, we also discuss the opportunities and challenges of metabolomics in nowadays HCC precision medicine. As technologies improving and metabolite biomarkers discovering, metabolomics has made a major step toward more timely and effective precision medicine for HCC patients.

Exploring the metabolome of seminal plasma in two different horse types: Light versus draft stallions

The application of the 'omics' studies in the field of animal reproduction has been aimed at identifying novel biomarkers of fertility since the last few years. When assessing reproductive efficiency in horses, breed should also be taken into account as it can influence semen quality and fertility. Considering the growing interest in metabolomic analysis to evaluate male fertility, we aimed to investigate the metabolomic profile of seminal plasma in two different horse breeds. Twelve healthy stallions, n.6 American Quarter Horse (AQH) and n.6 Italian Draft Horse (IDH) stallions, regularly used for artificial insemination, were included in the study. Two semen collections, performed 30-day apart, were considered for the assessment of semen parameters including gel-free volume, spermatozoa (spz) concentration, spz progressive motility and seminal plasma analysis by ¹ H-NMR.Semen characteristics differed between IDH and AQH (p < .05) as well as the first cycle conception rate that was higher in AQH than IDH (p = .001). Metabolomic analysis quantified 56 molecules in equine seminal plasma, with 11 metabolites showing different concentrations in IDH compared to AQH (p < .05).This study provided evidence of differences in seminal plasma metabolites' concentrations between studied horse types, highlighting specific metabolomic fingerprints characterizing AQH and IDH sperm.

Multigenerational Exposure to Uranium Changes Sperm Metabolome in Rats

Male infertility is a major public health issue that can be induced by a host of lifestyle risk factors such as environment, nutrition, smoking, stress, and endocrine disruptors. Regarding the human population exposed to uranium, it is necessary to explore these effects on male reproduction in multigenerational studies. The sensitivity of mass spectrometry (MS)-based methods has already proved to be extremely useful in metabolite identification in rats exposed to low doses of uranium, but also in human sperm. We applied this method to rat sperm over three generations (F0, F1 and F2) with multigenerational uranium exposure. Our results show a significant content of uranium in generation F0, and a reduction in the pregnancy rate only in generation F1. Based on principal component analysis (PCA), we observed discriminant profiles between generations. The partial least squares discriminant analysis (PLS-DA) of the 48 annotated variables confirmed that parental exposure of generation F0 (during both the preconceptional and prenatal periods) can have metabolic effects on spermatozoa for the next two generations. Metabolomics applied to epididymal spermatozoa is a novel approach to detecting the multigenerational effects of uranium in an experimental model, but could be also recommended to identify potential biomarkers evaluating the impact of uranium on sperm in exposed infertile men.

Omics in Seminal Plasma: An Effective Strategy for Predicting Sperm Retrieval Outcome in Non-obstructive Azoospermia

Non-obstructive azoospermia (NOA) is a severe form of male factor infertility resulting from the impairment of sperm production. Surgical sperm retrieval followed by intracytoplasmic sperm injection (ICSI) is the only alternative for NOA patients to have their own genetic children. Nevertheless, due to an approximately 50% chance of success, harvesting sperm from these patients remains challenging. Thus, discovering noninvasive biomarkers, which are able to reliably predict the probability of sperm acquisition, not only can eliminate the risk of surgery but also can lower the costs of NOA diagnosis and treatment. Seminal plasma is the non-cellular and liquid portion of the ejaculate that consists of the secretions originating from testes and male accessory glands. In past years, a wide range of biomolecules including DNAs, RNAs, proteins, and metabolic intermediates have been identified by omics techniques in human seminal plasma. The current review aimed to briefly describe genomic, transcriptomic, proteomic, and metabolomic profiles of human seminal plasma in an attempt to introduce potential candidate noninvasive biomarkers for sperm-retrieval success in men with NOA.

Association of the serum metabolomic profile by nuclear magnetic resonance spectroscopy with sperm parameters: a cross-sectional study of 325 men

OBJECTIVE

To determine whether 155 circulating metabolic measures relevant to lifestyle and metabolic health are associated with sperm parameters, as measured by concentration, motility, and total motile sperm count (TMSC).

STUDY DESIGN

Cross sectional.

SETTING

University hospital.

PATIENT(S)

Three hundred twenty-five men prospectively recruited between April 1, 2017 and March 31, 2019.

INTERVENTION(S)

Detailed demographic, lifestyle, fertility, medical history, and semen analysis with quantification of nonfasting serum lipids, lipoprotein subclasses, and low-molecular weight metabolites (including amino acids, glycolysis, and inflammatory markers) by nuclear magnetic resonance (NMR) spectroscopy.

MAIN OUTCOME MEASURE(S)

Association of serum metabolic profiles with sperm parameters.

RESULT(S)

The age of the participants was mean 37.2 years, with a median sperm concentration of 35 million/mL and median motility of 53%. Of these men, 76% had a TMSC >15 million, 10% had 5-15 million, and 14% had <5 million. In both univariate and confounder adjusted analyses, an extensive range of lipids and lipoproteins, glycolysis-related metabolites, amino acids, ketone bodies, creatinine, or albumin showed no strong statistically significant association with sperm concentration, motility, or the odds of having a reduced or low TMSC. Higher levels of glycolysis metabolites and ketone bodies were associated with an increased odds of TMSC <15 million compared with ≥15 million (odds ratios of ∼1.2-1.3), and several lipids/lipoprotein concentrations appeared to protect against very low TMSC (<5 million compared with ≥5 million) with odds ratios of ∼0.8 or greater.

CONCLUSION(S)

Several metabolites exhibited potentially clinically relevant strength of association with the odds of a low TMSC and warrant replication.

Sperm selection in IVF: the long and winding road from bench to bedside

Spermatozoa wage battle to conquer fertilization but the traits needed to succeed remain elusive. The natural advantageous qualities that enable only a few selected sperm cells to reach the site of fertilization remain unknown. Although in vitro fertilization (IVF) facilitates the job of spermatozoa, a universally acceptable means of sperm selection is yet to be developed. No objective or reliable sperm quality indicators have been established and sperm selection is, to a great extent, based on subjective qualitative evaluation. The best method for sperm selection in IVF presents several challenges: intrinsic sperm qualities cannot be evaluated and the ideal endpoint for these studies is debatable. An ideal method for sperm selection in ART should be noninvasive and cost-effective, and allow the identification of high-quality spermatozoa and yield better outcomes in terms of pregnancy and live birth rates. This narrative review included 85 papers and focused on the new available methods and technologies that might shed some light on sperm selection in IVF. It discusses the available data on microfluidic devices, omics profiling, micronuclei studies, sperm plasma membrane markers, and other techniques, such as Magnetic Activated Cell Sorting (MACS), Raman micro-spectroscopy, and artificial intelligence systems. The new techniques herein reviewed offer fresh approaches to an old problem, for which a definite solution has yet to cross the bridge from bench to IVF clinics around the world, since clinical usefulness and application remain unproven.

Profiling of serum metabolites in advanced colon cancer using liquid chromatography-mass spectrometry

Lymph node metastasis remains a key factor that affects the prognosis of patients with colon cancer. The aim of the present study was to identify and evaluate serum metabolites as biomarkers for the detection of tumor lymph node metastasis and the prediction of patient survival. The present study analyzed the metabolites in the serum of patients with advanced colon cancer both with and without lymph node metastasis. Blood samples from 104 patients with stage T3 colon cancer were collected and analyzed using liquid chromatography-mass spectrometry. The metabolites were structurally confirmed with data from the Human Metabolome Database. The association between the serum metabolites and the clinicopathological characteristics and survival time of patients from the present study was analyzed. Overall, 227 different metabolites were identified in the serum of patients with stage T3 colon cancer with or without lymph node metastasis. Furthermore, 17 of these metabolites may potentially distinguish those patients with lymph node metastasis from those patients without. In addition, five factors, including abscisic acid, calcitroic acid and glucosylsphingosine presence in the serum, age and sex, were identified as independent predictors for lymph node metastasis (P<0.05). Furthermore, three factors, including abscisic acid, calcitroic acid and glucosylsphingosine presence in the serum were independent predictors for patient survival (P<0.05). In conclusion, the serum levels of abscisic acid, calcitroic-acid and glucosylsphingosine may be considered as potential biomarkers to predict the occurrence of lymph node metastasis and the survival time of patients with colon cancer.

Seminal plasma metabolites mediate the associations of multiple environmental pollutants with semen quality in Chinese men

Environmental exposure to arsenic, phthalate esters (PAEs) and perfluorinated compounds (PFCs) has been associated with human semen quality. However, the epidemiological "black-box" of these associations remains poorly uncovered. In this study, based on the association analysis between arsenic, PAE and PFC exposure and semen quality parameters (i.e., semen volume, sperm concentration, sperm count, progressive motility, total motility and normal morphology) in a Chinese male population, we explored the seminal plasma metabolic signatures that may mediate the exposure-outcome relations by using the meet-in-metabolite-analysis (MIMA) approach. As a result, a negative association was found between DMA and sperm concentration, whereas MEHP and PFHxS were positively associated with sperm count and concentration, respectively. Metabolomics analysis revealed that sixteen and twenty-two seminal plasma metabolites were related to sperm concentration and count, respectively, and they are mainly involved in fatty acid, lipid and amino acid metabolism. Moreover, it was further indicated that eicosatetraenoate, carnitines and DHA may impact the inverse association between DMA and sperm concentration, while eicosatetraenoate, carnitines, DHA, PGB2 and tocotrienol are possible mediators of the positive association between PFHxS and sperm concentration. As these metabolic biomarkers are relevant to antioxidation and fatty acid β-oxidation, we suggest that redox balance and energy generation shifts in seminal plasma are involved in the association of human semen quality with environmental DMA and PFHxS exposure.

Characterizing semen abnormality male infertility using non-targeted blood plasma metabolomics

Semen abnormality (SA) male infertility has become a worldwide reproductive health problem. The invasive tests (e.g., testicular biopsy) and labor-intensive methods of semen collection severely inhibit diagnosis of male infertility. In addition, the pathogenesis and biological interpretation of male infertility are still obscure. In this report, a total of 84 semen abnormality (SA) patients, diagnosed as teratozoospermia (TE, n = 21), asthenozoospermia (AS, n = 23), oligozoospermia (OL, n = 20), azoospermia (AZ, n = 20), and age-matched healthy controls (HC, n = 29) were analyzed by GC-MS for discrimination analysis and discovery of potential biomarkers. Twenty-three biomarkers were obtained by multivariate statistical method (partial least squares-discriminant analysis, PLS-DA) and univariate statistical method (analysis of variance, ANOVA) with comparisons of TE versus HC, AS versus HC, OL versus HC and AZ versus HC. Based on those biomarkers, the most relevant pathways were mainly associated with the metabolism of carbohydrates, amino acids, and lipids. The principal metabolic alternations in SA male infertility included increased levels of energy-related metabolisms, such as tricarboxylic acid cycle, pyruvate metabolism, glyoxylate and dicarboxylate metabolism, glycine, serine, threonine metabolism and saturated fatty acid metabolism. Furthermore, increased levels of glutathione metabolism were related to oxidative stress. Finally, decreased levels of arginine and proline metabolism and inositol phosphate metabolism were observed. In conclusion, blood plasma metabolomics is powerful for characterizing metabolic disturbances in SA male infertility. From metabolic pathway analysis, energy production, oxidation stress and the released enzyme during spermatogenesis take the primary responsibilities for SA male infertility.

Co-Culture Systems for the Production of Secondary Metabolites: Current and Future Prospects

Microorganisms are the great sources of Natural Products (NPs); these are imperative to their survival apart from conferring competitiveness amongst each other within their environmental niches. Primary and secondary metabolites are the two major classes of NPs that help in cell development, where antimicrobial activity is closely linked with secondary metabolites. To capitalize on the effects of secondary metabolites, co-culture methods have been often used to develop an artificial microbial community that promotes the action of these metabolites. Different analytical techniques will subsequently be employed based on the metabolite specificity and sensitivity to further enhance the metabolite induction. Liquid Chromatography-Mass Spectrometry (LC-MS) and Gas Chromatography (GC)-MS are commonly used for metabolite separation while Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) have been used as tools to elucidate the structure of compounds. This review intends to discuss current systems in use for co-culture in addition to its advantages, with discourse into the investigation of specific techniques in use for the detailed study of secondary metabolites. Further advancements and focus on co-culture technologies are required to fully realize the massive potential in synthetic biological systems.

Metabolomic profiling reveals correlations between spermiogram parameters and the metabolites present in human spermatozoa and seminal plasma

In 50% of all infertility cases, the male is subfertile or infertile, however, the underlying mechanisms are often unknown. Even when assisted reproductive procedures such as in vitro fertilization and intracytoplasmic sperm injection are performed, the causes of male factor infertility frequently remain elusive. Since the overall activity of cells is closely linked to their metabolic capacity, we analyzed a panel of 180 metabolites in human sperm and seminal plasma and elucidated their associations with spermiogram parameters. Therefore, metabolites from a group of 20 healthy donors were investigated using a targeted LC-MS/MS approach. The correlation analyses of the amino acids, biogenic amines, acylcarnitines, lysophosphatidylcholines, phosphatidylcholines, sphingomyelins and sugars from sperm and seminal plasma with standard spermiogram parameters revealed that metabolites in sperm are closely related to sperm motility, whereas those in seminal plasma are closely related to sperm concentration and morphology. This study provides essential insights into the metabolome of human sperm and seminal plasma and its associations with sperm functions. This metabolomics technique could be a promising screening tool to detect the factors of male infertility in cases where the cause of infertility is unclear.

Alcohol-Induced Hepatic Steatosis: A Comparative Study to Identify Possible Indicator(s) of Alcoholic Fatty Liver Disease

Background

Fatty liver is an early sign of both nonalcoholic and alcoholic fatty liver diseases. Ethanol feeding using a Lieber-DeCarli liquid diet (LD) model which contains 35% fat to rats or mice is a well-established model for alcoholic fatty liver. However, LD diet alone can also induce fatty liver and its differential metabolic profile may be able to differentiate steatosis induced by LD versus LD plus ethanol.

Purpose

We investigated the lipidomic differences in the livers of Sprague-Dawley (SD) rats fed a pellet diet (PD), LD and liquid ethanol diet (LED) for six weeks.

Study Design

Male Sprague Dawley rats were fed with nonalcoholic diets PD, LD or LED (ethanol in LD) for six weeks. Lipids were extracted and analyzed by nuclear magnetic resonance (NMR)- based metabolomics. The NMR data obtained was analyzed by multivariate Principal Component Analysis (PCA) and Spotfire DecisionSite 9.0 software to compare PD versus LD and LD versus LED groups.

Results

PCA of the NMR spectral data of livers of both comparisons showed a clear separation of PD from LD group and LD from LED group indicating differences in lipid profiles which corresponded with changes in total lipid weights. LD showed increases for cholesterol, esterified cholesterol, cholesterol acetate and triglycerides with decreases for fatty acyl chain, diallylic and allylic protons, while the LED showed increases in esterified cholesterol, cholesterol acetate, fatty acid methyl esters, allylic protons and some triglyceride protons with decreases in free cholesterol and phosphatidylcholine (PC).

Conclusion

Our data suggest that altered lipid signature or PC levels could be an indicator to differentiate between nonalcoholic versus alcoholic fatty liver.

JAK/STAT and TGF-ß activation as potential adverse outcome pathway of TiO2NPs phototoxicity in Caenorhabditis elegans

Titanium dioxide nanoparticles (TiO₂NPs) are widely used nanoparticles, whose catalytic activity is mainly due to photoactivation. In this study, the toxicity of TiO₂NPs was investigated on the nematode Caenorhabditis elegans, with and without UV activation. Comparative analyses across the four treatments revealed that UV-activated TiO₂NPs led to significant reproductive toxicity through oxidative stress. To understand the underlying molecular mechanism, transcriptomics and metabolomics analyses were conducted, followed by whole-genome network-based pathway analyses. Differential expression analysis from microarray data revealed only 4 DEGs by exposure to TiO₂NPs alone, compared to 3,625 and 3,286 DEGs by UV alone and UV-activated TiO₂NPs, respectively. Pathway analyses suggested the possible involvement of the JAK/STAT and TGF-ß pathways in the phototoxicity of TiO₂NPs, which correlated with the observation of increased gene expression of those pathways. Comparative analysis of C. elegans response across UV activation and TiO₂NPs exposure was performed using loss-of-function mutants of genes in these pathways. Results indicated that the JAK/STAT pathway was specific to TiO₂NPs, whereas the TGF-ß pathway was specific to UV. Interestingly, crosstalk between these pathways was confirmed by further mutant analysis. We consider that these findings will contribute to understand the molecular mechanisms of toxicity of TiO₂NPs in the natural environment.

Serum metabolomic profiling of human gastric cancer and its relationship with the prognosis

Objective

This study was aimed to investigate serum metabolites in gastric cancer (GC) patients and their relationships with the prognosis of GC in order to find potential specific serum biomarkers for GC.

Methods

Blood samples of 125 GC patients of unifocal GC at initial stage and 38 healthy people recruited in our hospital from September 2008 to August 2009 were analyzed by using high performance liquid chromatography coupled with electrospray ionization/quadrupole-time-of-flight mass spectrometry (HPLCESI/Q-TOFMS). Multiple statistical methods like principal component analysis (PCA), hierarchical clustering analysis, partial least squares discriminant analysis (PLS-DA), multivariate COX regression analysis, variance analysis and K-M survival curve were applied to analyze the raw obtained mass data in order to analyze the independent prognostic factors of GC. The structures of these metabolites were confirmed by comparing the m/z ratio and ion mode of with the data published from HMDB (www.hmdb.ca) databases.

Results

By PLS-DA test, 16 serum metabolites in ESI⁺ mode of VIP>1 in both test group and validation group could definitely distinguish GC patients from healthy peoples (p<0.05). Multivariate COX regression analysis showed TNM staging, 2,4-hexadienoic acid, 4-methylphenyl dodecanoate and glycerol tributanoate were independent prognostic factors of GC (p<0.05). In the K-M survival analysis, the survival rate in high level group of the 3 selected serum metabolites together or alone was significant lower than in those in low level group (p<0.05).

Conclusion

Low serum levels of 2,4-hexadienoic acid, 4-methylphenyl dodecanoate and glycerol tributanoate may be important independent prognostic factors of GC.

Seminal plasma metabolomics approach for the diagnosis of unexplained male infertility

We used a gas chromatography-mass spectrometry (GC-MS) based metabolomics approach to obtain the metabolic profiling of unexplained male infertility (UMI), and identified seminal plasma biomarkers associated with UMI by a two-stage population study. A robust OPLS-DA model based on these identified metabolites was able to distinguish 82% of the UMI patients from health controls with a specificity of 92%. In this model, 44 metabolites were found differentially expressed in UMI subjects compared with health controls. By pathway enrichment analysis, we identified several major changed metabolic pathways related to UMI. Our findings provide new perspective for the diagnosis of UMI.

Metabolomics for clinical use and research in chronic kidney disease

Chronic kidney disease (CKD) has a high prevalence in the general population and is associated with high mortality; a need therefore exists for better biomarkers for diagnosis, monitoring of disease progression and therapy stratification. Moreover, very sensitive biomarkers are needed in drug development and clinical research to increase understanding of the efficacy and safety of potential and existing therapies. Metabolomics analyses can identify and quantify all metabolites present in a given sample, covering hundreds to thousands of metabolites. Sample preparation for metabolomics requires a very fast arrest of biochemical processes. Present key technologies for metabolomics are mass spectrometry and proton nuclear magnetic resonance spectroscopy, which require sophisticated biostatistic and bioinformatic data analyses. The use of metabolomics has been instrumental in identifying new biomarkers of CKD such as acylcarnitines, glycerolipids, dimethylarginines and metabolites of tryptophan, the citric acid cycle and the urea cycle. Biomarkers such as c-mannosyl tryptophan and pseudouridine have better performance in CKD stratification than does creatinine. Future challenges in metabolomics analyses are prospective studies and deconvolution of CKD biomarkers from those of other diseases such as metabolic syndrome, diabetes mellitus, inflammatory conditions, stress and cancer.

Serum Metabolomic Profiling Identifies Characterization of Non-Obstructive Azoospermic Men

Male infertility is considered a common health problem, and non-obstructive azoospermia with unclear pathogenesis is one of the most challenging tasks for clinicians. The objective of this study was to investigate the differential serum metabolic pattern in non-obstructive azoospermic men and to determine potential biomarkers related to spermatogenic dysfunction. Serum samples from patients with non-obstructive azoospermia (n = 22) and healthy controls (n = 31) were examined using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Serum metabolomic profiling could differentiate non-obstructive azoospermic patients from healthy control subjects. A total of 24 metabolites were screened and identified as potential markers, many of which are involved in energy production, oxidative stress and cell apoptosis in spermatogenesis. Moreover, the results showed that various metabolic pathways, including d-glutamine and d-glutamate metabolism, taurine and hypotaurine metabolism, pyruvate metabolism, the citrate cycle and alanine, aspartate and glutamate metabolism, were disrupted in patients with non-obstructive azoospermia. Our results indicated that the serum metabolic disorders may contribute to the etiology of non-obstructive azoospermia. This study suggested that serum metabolomics could identify unique metabolic patterns of non-obstructive azoospermia and provide novel insights into the pathogenesis underlying male infertility.

Understanding the pathogenesis of hip fracture in the elderly, osteoporotic theory is not reflected in the outcome of prevention programmes

Hip fractures are an acute and worsening public health problem. They mainly affect elderly people, a population group that is highly vulnerable to disease and accidents, and to falls in particular. Although it has been suggested that osteoporosis is the cause of hip fractures, they mainly occur after a fall has been suffered. The underlying causes of a fall are not related to osteoporosis, although pharmaceutical companies have coined the term “osteoporotic fracture” for hip fractures in the elderly. Drug treatments for osteoporosis have not diminished the frequency of these injuries, nor have they prevented the occurrence of a subsequent fracture. Since pharmaceutical interests require osteoporosis to be considered a disease, rather than a normal condition of senescence, they go further by assuming that treatment for osteoporosis is essential, and that this policy will diminish the incidence of hip fractures. On the other hand, the origin and treatment of conditions that may be conducive to provoking falls are very difficult to elucidate. In this paper, we consider some of the medical and social problems that arise in this area, as well as conflicts of interest regarding the aetiopathogenesis and prevention of hip fracture, and propose a new paradigm for the prevention of falls.

Effectiveness of an individualized program of muscular strength and endurance with aerobic training for improving germ cell cancer-related fatigue in men undergoing chemotherapy: EFICATEST study protocol for a randomized controlled trial

Background

Patients with testicular germ cell cancer (GCC) have a high cure rate; however, cancer-related fatigue is the most common complication among patients with GCC undergoing treatment with chemotherapy. Although exercise is widely recommended, information about the physio-pathological effects of cancer therapy on skeletal muscle is very limited. Our aim is to evaluate the effects of an individualized program of muscular strength and endurance with aerobic training on cancer-related fatigue.

Methods/Design

The present study is a randomized controlled trial comparing an individualized program of muscular strength and endurance with aerobic training compared to a control group. We will conduct this trial in patients undergoing chemotherapy, recruited by the Department of Oncology of Virgen de la Victoria Hospital (Málaga). Patients will be included and evaluated before the first cycle of chemotherapy and assigned randomly to the experimental or control group. Cancer-related fatigue, physical condition and biological samples will be measured at the beginning and at the end of an 8-week intervention by the same evaluator, who will be unaware of the allocation of participants to each group. Furthermore, there will be monitoring for 6 months (24 weeks) after training for all outcome variables.

Discussion

This study hopes to offer patients with GCC an individualized exercise program with aerobic training for cancer-related fatigue. Such a scheme, if beneficial, could be implemented successfully within public health.

Trial registration

ClinicalTrials.gov Identifier: NCT02433197. Date of registration: 13 April 2015.

Metabolomic Analysis Using Liquid Chromatography/Mass Spectrometry for Gastric Cancer

Metabolomics is a post-genomics research field for analysis of low molecular weight compounds in biological samples and has shown great potentials for elucidating complex mechanisms associated with diseases. However, metabolomics studies on gastric cancer (GC), which is the second leading cause of cancer death worldwide, remain scarce, and the molecular mechanisms to metabolomics phenotypes are also still not fully understood. This study reports that the metabolic pathways can be exploited as biomarkers for diagnosis and treatment of GC progression as a case study. Importantly, the urinary metabolites and metabolic patterns were analyzed by high-throughput liquid chromatography mass spectrometry (LC-MS) metabolomics strategy coupled with chemometric evaluation. Sixteen metabolites (nine upregulated and seven downregulated) were differentially expressed and may thus serve as potential urinary biomarkers for human GC. These metabolites were mainly involved in multiple metabolic pathways, including citrate cycle (malic acid, succinic acid, 2-oxoglutarate, citric acid), cyanoamino acid metabolism (glycine, alanine), primary bile acid biosynthesis (glycine, taurine, glycocholic acid), arginine and proline metabolism (urea, L-proline), and fatty acid metabolism (hexadecanoic acid), among others. Network analysis validated close association between these identified metabolites and altered metabolic pathways in a variety of biological processes. These results suggest that urine metabolic profiles have great potential in detecting GC and may aid in understanding its underlying mechanisms. It provides insight into disease pathophysiology and can serve as the basis for developing disease biomarkers and therapeutic interventions for GC diseases.

Identification of endogenous metabolites in human sperm cells using proton nuclear magnetic resonance ((1) H-NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS)

The objective of this study was to contribute to the first comprehensive metabolomic characterization of the human sperm cell through the application of two untargeted platforms based on proton nuclear magnetic resonance ((1) H-NMR) spectroscopy and gas chromatography coupled to mass spectrometry (GC-MS). Using these two complementary strategies, we were able to identify a total of 69 metabolites, of which 42 were identified using NMR, 27 using GC-MS and 4 by both techniques. The identity of some of these metabolites was further confirmed by two-dimensional (1) H-(1) H homonuclear correlation spectroscopy (COSY) and (1) H-(13) C heteronuclear single-quantum correlation (HSQC) spectroscopy. Most of the metabolites identified are reported here for the first time in mature human spermatozoa. The relationship between the metabolites identified and the previously reported sperm proteome was also explored. Interestingly, overrepresented pathways included not only the metabolism of carbohydrates, but also of lipids and lipoproteins. Of note, a large number of the metabolites identified belonged to the amino acids, peptides and analogues super class. The identification of this initial set of metabolites represents an important first step to further study their function in male gamete physiology and to explore potential reasons for dysfunction in future studies. We also demonstrate that the application of NMR and MS provides complementary results, thus constituting a promising strategy towards the completion of the human sperm cell metabolome.

Metabolomics analysis of seminal plasma in infertile males with kidney-yang deficiency: a preliminary study

Traditional Chinese medicine (TCM) is an important treatment for male infertility, and its application to therapy is dependent on differentiation of TCM syndromes. This study aims to investigate the changes in metabolites and metabolic pathways in infertile males with Kidney-Yang Deficiency syndrome (KYDS) via metabolomics approaches. Seminal plasma samples were collected from 18 infertile males with KYDS and 18 fertile males. Liquid chromatography and mass spectrometry were used to characterize metabolomics profiles. Principal component analysis (PCA), partial least squares-discriminate analysis (PLS-DA), and pathway analysis were used for pattern recognition and metabolite identification. PCA and PLS-DA results differentiated the two groups of patients. Forty-one discriminating metabolites (18 in positive mode and 23 in negative mode) were identified. Seven metabolites were related to five potential metabolic pathways associated with biosynthesis and metabolism of aromatic amino acids, tricarboxylic acid cycle, and sphingolipid metabolism. The changes in metabolic pathways may play an important role in the origin of KYDS-associated male infertility. Metabolomics analysis of seminal plasma may be used to differentiate TCM syndromes of infertile males, but further research must be conducted.

Chemiomics: network reconstruction and kinetics of port wine aging

Network reconstruction (NR) has proven to be useful in the detection and visualization of relationships among the compounds present in a Port wine aging data set. This view of the data provides a considerable amount of information with which to understand the kinetic contexts of the molecules represented by peaks in each chromatogram. The aim of this study was to use NR together with the determination of kinetic parameters to extract more information about the mechanisms involved in Port wine aging. The volatile compounds present in samples of Port wines spanning 128 years in age were measured with the use of GC-MS. After chromatogram alignment, a peak matrix was created, and all peak vectors were compared to one another to determine their Pearson correlations over time. A correlation network was created and filtered on the basis of the resulting correlation values. Some nodes in the network were further studied in experiments on Port wines stored under different conditions of oxygen and temperature in order to determine their kinetic parameters. The resulting network can be divided into three main branches. The first branch is related to compounds that do not directly correlate to age, the second branch contains compounds affected by temperature, and the third branch contains compounds associated with oxygen. Compounds clustered in the same branch of the network have similar expression patterns over time as well as the same kinetic order, thus are likely to be dependent on the same technological parameters. Network construction and visualization provides more information with which to understand the probable kinetic contexts of the molecules represented by peaks in each chromatogram. The approach described here is a powerful tool for the study of mechanisms and kinetics in complex systems and should aid in the understanding and monitoring of wine quality.

Basics of mass spectrometry based metabolomics

The emerging field of metabolomics, aiming to characterize small molecule metabolites present in biological systems, promises immense potential for different areas such as medicine, environmental sciences, agronomy, etc. The purpose of this article is to guide the reader through the history of the field, then through the main steps of the metabolomics workflow, from study design to structure elucidation, and help the reader to understand the key phases of a metabolomics investigation and the rationale underlying the protocols and techniques used. This article is not intended to give standard operating procedures as several papers related to this topic were already provided, but is designed as a tutorial aiming to help beginners understand the concept and challenges of MS-based metabolomics. A real case example is taken from the literature to illustrate the application of the metabolomics approach in the field of doping analysis. Challenges and limitations of the approach are then discussed along with future directions in research to cope with these limitations. This tutorial is part of the International Proteomics Tutorial Programme (IPTP18).