Serum ferritin/C-reactive protein ratio is a simple and effective biomarker for diagnosing iron deficiency in the context of systemic inflammation

BACKGROUND

Diagnosing iron deficiency is challenging in the presence of systemic inflammation.

AIM

To investigate the relationship between plasma C-reactive protein (CRP), serum ferritin (SF) and transferrin saturation (TS), with the objective of establishing a straightforward ratio applicable in the presence of inflammatory syndrome.

DESIGN

Test prospective cohort and validation retrospective cohort.

METHODS

A prospective cohort of inpatients (n = 140) assessed the correlation between CRP and SF/TS levels. The diagnostic performance of a determined ratio was evaluated for identifying iron deficiency (ID) using different definitions and in the presence of inflammation and/or chronic heart and/or kidney failure. A large validation cohort (n = 795) further assessed the predictive power of this ratio.

RESULTS

In a training cohort (median age 76 years [57-84]), a linear relation was observed between SF (µg/l) and CRP (mg/l), unlike with TS. The SF/CRP ratio accurately predicted ID, with receiver operating characteristic-area under the curve (ROC-AUC) values ranging from 0.85 to 0.92 for different ID definitions. A threshold of ≤6 demonstrated the highest Youden index (0.61). In the validation cohort (age 72 years [57-84]), the SF/CRP ratio exhibited an ROC-AUC of 0.88 [95% CI: 0.85-0.90], with an odds ratio of 37.9 [95% CI: 20.3-68.9] for the threshold of ≤6.

CONCLUSION

In this study, we demonstrated that the SF/CRP ratio, with a threshold of ≤6, is a simple and effective biomarker for ID, even in the presence of systemic inflammation or comorbidities. This ratio could potentially replace the complex set of criteria currently recommended by learned societies.

Efficacy and safety of e-cigarette use for smoking cessation: a systematic review and meta-analysis of randomized controlled trials

Background

Quitting smoking substantially reduces the risk of developing cardiovascular disease. Smokers are increasingly turning to electronic cigarettes (e-cigarettes) to help them quit smoking combustible cigarettes. However, the efficacy and safety of e-cigarettes for smoking cessation remain controversial.

Purpose

To examine the efficacy and safety of e-cigarette use for smoking cessation.

Methods

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing nicotine and non-nicotine e-cigarettes (alone, or in combination with behavioural and/or pharmacological interventions) to conventional smoking cessation therapies (pharmacological, behavioural, or both). We systematically searched MEDLINE, Embase, and the Cochrane Libraries. Inclusion was restricted to RCTs that reported biochemically validated abstinence at six months or greater. The primary comparison was nicotine e-cigarettes versus any (non-e-cigarette) conventional smoking cessation therapy. Count data were pooled using DerSimonian and Laird random-effects models with inverse variance weighting to obtain relative risks (RRs) and 95% confidence intervals (CIs).

Results

A total of six RCTs (n=3,401) were included, with maximum follow-up durations ranging from six to 12 months. Compared with conventional smoking cessation therapies, point estimates favoured nicotine e-cigarettes for the most rigorous criterion of abstinence, continuous abstinence, and point prevalence abstinence, although findings were inconclusive due to wide 95% CIs (Table 1). Similar trends were observed when comparing non-nicotine e-cigarettes to traditional smoking cessation therapies. Compared with non-nicotine e-cigarettes, nicotine e-cigarettes increased abstinence as defined by the most rigorous criterion. Although there was a signal suggesting a potential increased risk of respiratory adverse events with nicotine e-cigarettes versus traditional therapies, the 95% CI is wide.

Conclusion

E-cigarettes appear to be more efficacious than conventional nicotine pharmacotherapies and behavioural smoking cessation therapies. Although currently available safety data are inconclusive, e-cigarettes may be considered for smoking cessation given the established long-term health consequences of continued smoking.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Mr. Levett is supported by an Ivan Racheff Scholarship, funded through the McGill University Faculty of Medicine and Health Sciences Research Bursary Program. Dr. Filion is supported by a Senior Research Scholar award from the Fonds de recherche du Québec – Santé and a William Dawson Scholar award from McGill University.

Maternal ageing impairs mitochondrial DNA kinetics during early embryogenesis in mice

STUDY QUESTION

Does ageing affect the kinetics of the mitochondrial pool during oogenesis and early embryogenesis?

SUMMARY ANSWER

While we found no age-related change during oogenesis, the kinetics of mitochondrial DNA content and the expression of the factors involved in mitochondrial biogenesis appeared to be significantly altered during embryogenesis.

WHAT IS KNOWN ALREADY

Oocyte mitochondria are necessary for embryonic development. The morphological and functional alterations of mitochondria, as well as the qualitative and quantitative mtDNA anomalies, observed during ovarian ageing may be responsible for the alteration of oocyte competence and embryonic development.

STUDY DESIGN, SIZE, DURATION

The study, conducted from November 2016 to November 2017, used 40 mice aged 5–8 weeks and 45 mice aged 9–11 months (C57Bl6/CBA F(1)). A total of 488 immature oocytes, with a diameter ranging from 20 μm to more than 80 μm, were collected from ovaries, and 1088 mature oocytes or embryos at different developmental stages (two PN, one-cell, i.e. syngamy, two-cell, four-cell, eight-cell, morula and blastocyst) were obtained after ovarian stimulation and, for embryos, mating.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Mitochondrial DNA was quantified by quantitative PCR. We used quantitative reverse transcriptase PCR (RT-PCR) (microfluidic method) to study the relative expression of three genes involved in the key steps of embryogenesis, i.e. embryonic genome activation (HSPA1) and differentiation (CDX2 and NANOG), two mtDNA genes (CYB and ND2) and five genes essential for mitochondrial biogenesis (PPARGC1A, NRF1, POLG, TFAM and PRKAA). The statistical analysis was based on mixed linear regression models applying a logistic link function (STATA v13.1 software), with values of P < 0.05 being considered significant.

MAIN RESULTS AND THE ROLE OF CHANCE

During oogenesis, there was a significant increase in oocyte mtDNA content (P < 0.0001) without any difference between the two groups of mice (P = 0.73). During the first phase of embryogenesis, i.e. up to the two-cell stage, embryonic mtDNA decreased significantly in the aged mice (P < 0.0001), whereas it was stable for young mice (young/old difference P = 0.015). The second phase of embryogenesis, i.e. between the two-cell and eight-cell stages, was characterized by a decrease in embryonic mtDNA for young mice (P = 0.013) only (young/old difference P = 0.038). During the third phase, i.e. between the eight-cell and blastocyst stage, there was a significant increase in embryonic mtDNA content in young mice (P < 0.0001) but not found in aged mice (young/old difference P = 0.002). We also noted a faster expression of CDX2 and NANOG in the aged mice than in the young mice during the second (P = 0.007 and P = 0.02, respectively) and the third phase (P = 0.01 and P = 0.008, respectively) of embryogenesis. The expression of mitochondrial genes CYB and ND2 followed similar kinetics and was equivalent for both groups of mice, with a significant increase during the third phase (P < 0.01). Of the five genes involved in mitochondrial biogenesis, i.e. PPARGC1A, NRF1, POLG, TFAM and PRKAA, the expression of three genes decreased significantly during the first phase only in young mice (NRF1, P = 0.018; POLGA, P = 0.002; PRKAA, P = 0.010), with no subsequent difference compared to old mice. In conclusion, during early embryogenesis in the old mice, we suspect that the lack of a replicatory burst before the two-cell stage, associated with the early arrival at the minimum threshold value of mtDNA, together with the absence of an increase of mtDNA during the last phase, might potentially deregulate the key stages of early embryogenesis.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Because of the ethical impossibility of working on a human, this study was conducted only on a murine model. As superovulation was used, we cannot totally exclude that the differences observed were, at least partially, influenced by differences in ovarian response between young and old mice.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings suggest a pathophysiological explanation for the link observed between mitochondria and the deterioration of oocyte quality and early embryonic development with age.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the University of Angers, France, by the French national research centres INSERM and the CNRS and, in part, by PHASE Division, INRA. There are no competing interests.

The mitochondrial DNA content of cumulus cells may help predict embryo implantation

PURPOSE

The quantification of mtDNA in cumulus granulosa cells (CGCs) surrounding an oocyte has been positively linked with morphological embryonic quality. In the present study, we evaluated the link between the amount of mtDNA in CGCs surrounding an oocyte and the chances for the corresponding embryo of implanting and leading to an ongoing pregnancy.

METHODS

This is an observational study, performed on 84 oocyte-cumulus-complexes (OCCs) having led to the replacement of an embryo in the maternal uterus, retrieved from 71 patients undergoing IVF with intracytoplasmic sperm. The OCCs were classified in two groups, one including 26 OCCs having led to an implanted embryo and the other including 58 OCCs having led to a non-implanted embryo. The average mtDNA content of CGCs was assessed by using a quantitative real-time PCR technique.

RESULTS

Significantly higher mtDNA copy numbers in CGCs were associated with implanted embryos than with non-implanted embryos (mean 215 [sd 375] and 59 [sd 72], respectively; p < 10⁴). Multivariate analysis, taking into account the women's age, the embryo quality, and the AMH level, suggests an independent relationship between the mtDNA content of CGCs and the potential of embryo implantation.

CONCLUSION

During in vitro fertilization (IVF) procedures, the probability of the implantation of the embryo appears to be closely correlated to the mtDNA copy numbers in the CGCs. Our results highlight the interest of mtDNA quantification in GCGs as a biomarker of the potential of embryo implantation.

Targeted metabolomics reveals reduced levels of polyunsaturated choline plasmalogens and a smaller dimethylarginine/arginine ratio in the follicular fluid of patients with a diminished ovarian reserve

STUDY QUESTION

Does the metabolomic profile of the follicular fluid (FF) of patients with a diminished ovarian reserve (DOR) differ from that of patients with a normal ovarian reserve (NOR)?

SUMMARY ANSWER

The metabolomic signature of the FF reveals a significant decrease in polyunsaturated choline plasmalogens and methyl arginine transferase activity in DOR patients compared to NOR patients.

WHAT IS KNOWN ALREADY

The composition of the FF reflects the exchanges between the oocyte and its microenvironment during its acquisition of gametic competence. Studies of the FF have allowed identification of biomarkers and metabolic pathways involved in various pathologies affecting oocyte quality, but no large metabolomic analysis in the context of ovarian ageing and DOR has been undertaken so far.

STUDY DESIGN, SIZE, DURATION

This was an observational study of the FF retrieved from 57 women undergoing in vitro fertilization at the University Hospital of Angers, France, from November 2015 to September 2016. The women were classified in two groups: one including 28 DOR patients, and the other including 29 NOR patients, serving as controls.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients were enrolled in the morning of oocyte retrieval after ovarian stimulation. Once the oocytes were isolated for fertilization and culture, the FF was pooled and centrifuged for analysis. A targeted quantitative metabolomic analysis was performed using high-performance liquid chromatography coupled with tandem mass spectrometry, and the Biocrates Absolute IDQ p180 kit. The FF levels of 188 metabolites and several sums and ratios of metabolic significance were assessed by multivariate and univariate analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 136 metabolites were accurately quantified and used for calculating 23 sums and ratios. Samples were randomly divided into training and validation sets. The training set, allowed the construction of multivariate statistical models with a projection-supervised method, i.e. orthogonal partial least squares discriminant analysis (OPLS-DA), applied to the full set of metabolites, or the penalized least absolute shrinkage and selection operator with logistic regression (LASSO-LR), applied to the ratios and sums of the metabolites. Both multivariate models showed good predictive performances when applied to the validation set. The final penalized model retained the three most significant variables, i.e. the total dimethylarginine-to-arginine ratio (Total DMA/Arginine), the sum of the polyunsaturated choline plasmalogens (PUFA ae), and the patient's age. The negative coefficients of Total DMA/Arginine and PUFA ae indicated that these FF variables had lower values in DOR patients than in NOR patients.

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

This study presents two limitations. First, with this targeted metabolomics analysis, we have explored only a limited portion of the FF metabolome. Second, although the signature found was highly significant, the mechanism underlying the dysfunction remains undetermined.

WIDER IMPLICATIONS OF THE FINDINGS

The understanding of the mechanisms implied in ovarian ageing is essential for providing an adequate response to affected women desiring pregnancy. Our study proposes an incoming signature that may open new paths towards this goal.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the University Hospital of Angers, the University of Angers, and the French national research centers, INSERM and the CNRS. There were no competing interests.

Deep sequencing shows that oocytes are not prone to accumulate mtDNA heteroplasmic mutations during ovarian ageing

STUDY QUESTION

Does ovarian ageing increase the number of heteroplasmic mitochondrial DNA (mtDNA) point mutations in oocytes?

SUMMARY ANSWER

Our results suggest that oocytes are not subject to the accumulation of mtDNA point mutations during ovarian ageing.

WHAT IS KNOWN ALREADY

Ageing is associated with the alteration of mtDNA integrity in various tissues. Primary oocytes, present in the ovary since embryonic life, may accumulate mtDNA mutations during the process of ovarian ageing.

STUDY DESIGN, SIZE, DURATION

This was an observational study of 53 immature oocyte-cumulus complexes retrieved from 35 women undergoing IVF at the University Hospital of Angers, France, from March 2013 to March 2014. The women were classified in two groups, one including 19 women showing signs of ovarian ageing objectified by a diminished ovarian reserve (DOR), and the other, including 16 women with a normal ovarian reserve (NOR), which served as a control group.

PARTICIPANTS/MATERIALS, SETTING, METHODS

mtDNA was extracted from isolated oocytes, and from their corresponding cumulus cells (CCs) considered as a somatic cell compartment. The average mtDNA content of each sample was assessed by using a quantitative real-time PCR technique. Deep sequencing was performed using the Ion Torrent Proton for Next-Generation Sequencing. Signal processing and base calling were done by the embedded pre-processing pipeline and the variants were analyzed using an in-house workflow. The distribution of the different variants between DOR and NOR patients, on one hand, and oocyte and CCs, on the other, was analyzed with the generalized mixed linear model to take into account the cluster of cells belonging to a given mother.

MAIN RESULTS AND THE ROLE OF CHANCE

There were no significant differences between the numbers of mtDNA variants between the DOR and the NOR patients, either in the oocytes (P = 0.867) or in the surrounding CCs (P = 0.154). There were also no differences in terms of variants with potential functional consequences. De-novo mtDNA variants were found in 28% of the oocytes and in 66% of the CCs with the mean number of variants being significantly different (respectively 0.321, SD = 0.547 and 1.075, SD = 1.158) (P < 0.0001). Variants with a potential functional consequence were also overrepresented in CCs compared with oocytes (P = 0.0019).

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Limitations may be due to the use of immature oocytes discarded during the assisted reproductive technology procedure, the small size of the sample, and the high-throughput sequencing technology that might not have detected heteroplasmy levels lower than 2%.

WIDER IMPLICATIONS OF THE FINDINGS

The alteration of mtDNA integrity in oocytes during ovarian ageing is a recurring question to which our pilot study suggests a reassuring answer.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the University Hospital of Angers, the University of Angers, France, and the French national research centers, INSERM and the CNRS. There are nocompeting interests.

Mitochondrial complex I defect resulting from exercise-induced lower limb ischemia in patients with peripheral arterial disease

This study aims to compare the structural and mitochondrial alterations between muscle segments affected by exercise-induced ischemia and segments of the same muscle without ischemia, in the same subject. In a prospective analysis, 34 patients presenting either peripheral arterial disease or chronic coronary syndrome without any evidence of peripheral arterial disease were eligible for inclusion based on findings indicating a need for either a femoro-popliteal bypass or a saphenous harvesting for coronary bypass. Before surgery, we assessed the level of exercise-induced ischemia in proximal and distal sections of the thigh by the measurement of transcutaneous oxygen pressure during an exercise treadmill test. Distal and proximal biopsies of the sartorius muscle were procured during vascular surgical procedures to assess mitochondrial function and morphometric parameters of the sartorius myofibers. Comparisons were made between the distal and proximal biopsies, with respect to these parameters. Thirteen of the study patients that initially presented with peripheral arterial disease had evidence of an isolated distal thigh exercise-induced ischemia, associated with a 35% decrease in the mitochondrial complex I enzymatic activity in the distal muscle biopsy. This defect was also associated with a decreased expression of the manganese superoxide dismutase enzyme and with alterations of the shapes of the myofibers. No functional or structural alterations were observed in the patients with coronary syndrome. We validated a specific model ischemia in peripheral arterial disease characterized by muscular alterations. This "Distal-Proximal-Sartorius Model" would be promising to explore the physiopathological consequences specific to chronic ischemia. NEW & NOTEWORTHY We compared proximal versus distal biopsies of the sartorius muscle in patients with superficial femoral artery stenosis or occlusion and proof of, distal only, regional blood flow impairment with exercise oximetry. We identified a decrease in the mitochondrial complex I enzymatic activity and antioxidant system impairment at the distal level only. We validate a model to explore the physiopathological consequences of chronic muscle ischemia.

The mitochondrial DNA content of cumulus granulosa cells is linked to embryo quality

STUDY QUESTION

Could the mitochondrial DNA (mtDNA) content of cumulus granulosa cells (CGCs) be related to oocyte competence?

SUMMARY ANSWER

The quality of embryos obtained during IVF procedures appears to be linked to mtDNA copy numbers in the CGCs.

WHAT IS KNOWN ALREADY

Oocyte quality is linked to oocyte mtDNA content in the human and other species, and the mtDNA copy number of the oocyte is related to that of the corresponding CGCs. Moreover, the quantification of CGC mtDNA has recently been proposed as a biomarker of embryo viability.

STUDY DESIGN SIZE, DURATION

An observational study was performed on 452 oocyte-cumulus complexes retrieved from 62 patients undergoing ICSI at the ART Center of the University Hospital of Angers, France, from January to May 2015.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The average mtDNA content of CGCs was assessed by using a quantitative real-time PCR technique. The relationship between CGC mtDNA content and oocyte maturity and fertilizability, on one hand, and embryo quality, on the other, was investigated using univariate and multivariate generalized models with fixed and mixed effects.

MAIN RESULTS AND THE ROLE OF CHANCE

No relationship was found between CGC mtDNA content and oocyte maturity or fertilizability. In contrast, there was a significant link between the content of mtDNA in CGCs surrounding an oocyte and the embryo quality, with significantly higher mtDNA copy numbers being associated with good quality embryos compared with fair or poor quality embryos [interquartile range, respectively, 738 (250-1228) and 342 (159-818); P = 0.006]. However, the indication provided by the quantification of CGC mtDNA concerning the eventuality of good embryo quality was seriously subject to patient effect (AUC = 0.806, 95%CI = 0.719-0.869). The quantity of CGC mtDNA was influenced by BMI and smoking.

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

The quantification of CGC mtDNA may indicate embryo quality. However, since it is affected by patient specificity, it should be used with caution. It remains to be seen whether this marker could directly predict the implantation capacity of the embryo, which is the main objective in IVF practice.

WIDER IMPLICATIONS OF THE FINDINGS

Our study suggests that the quantification of CGC mtDNA may be a novel biomarker of embryo viability. However, patient specificity makes it impossible to establish a general threshold value, valid for all patients. Nevertheless, further studies are needed to determine whether the quantification of CGC mtDNA may, in combination with the morpho-kinetic method, offer an additional criterion for selecting the best embryo for transfer from a given cohort.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the University Hospital of Angers, the University of Angers, France, and the French national research centres INSERM and the CNRS. There were no competing interests.

Lipidomics Reveals Cerebrospinal-Fluid Signatures of ALS

Amyotrophic lateral sclerosis (ALS), the commonest adult-onset motor neuron disorder, is characterized by a survival span of only 2–5 years after onset. Relevant biomarkers or specific metabolic signatures would provide powerful tools for the management of ALS. The main objective of this study was to investigate the cerebrospinal fluid (CSF) lipidomic signature of ALS patients by mass spectrometry to evaluate the diagnostic and predictive values of the profile. We showed that ALS patients (n = 40) displayed a highly significant specific CSF lipidomic signature compared to controls (n = 45). Phosphatidylcholine PC(36:4), higher in ALS patients (p = 0.0003) was the most discriminant molecule, and ceramides and glucosylceramides were also highly relevant. Analysis of targeted lipids in the brain cortex of ALS model mice confirmed the role of some discriminant lipids such as PC. We also obtained good models for predicting the variation of the ALSFRS-r score from the lipidome baseline, with an accuracy of 71% in an independent set of patients. Significant predictions of clinical evolution were found to be correlated to sphingomyelins and triglycerides with long-chain fatty acids. Our study, which shows extensive lipid remodelling in the CSF of ALS patients, provides a new metabolic signature of the disease and its evolution with good predictive performance.

The combination of four analytical methods to explore skeletal muscle metabolomics: Better coverage of metabolic pathways or a marketing argument?

OBJECTIVES

Metabolomics is an emerging science based on diverse high throughput methods that are rapidly evolving to improve metabolic coverage of biological fluids and tissues. Technical progress has led researchers to combine several analytical methods without reporting the impact on metabolic coverage of such a strategy. The objective of our study was to develop and validate several analytical techniques (mass spectrometry coupled to gas or liquid chromatography and nuclear magnetic resonance) for the metabolomic analysis of small muscle samples and evaluate the impact of combining methods for more exhaustive metabolite covering.

DESIGN AND METHODS

We evaluated the muscle metabolome from the same pool of mouse muscle samples after 2 metabolite extraction protocols. Four analytical methods were used: targeted flow injection analysis coupled with mass spectrometry (FIA-MS/MS), gas chromatography coupled with mass spectrometry (GC-MS), liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS), and nuclear magnetic resonance (NMR) analysis. We evaluated the global variability of each compound i.e., analytical (from quality controls) and extraction variability (from muscle extracts). We determined the best extraction method and we reported the common and distinct metabolites identified based on the number and identity of the compounds detected with low analytical variability (variation coefficient<30%) for each method. Finally, we assessed the coverage of muscle metabolic pathways obtained.

RESULTS

Methanol/chloroform/water and water/methanol were the best extraction solvent for muscle metabolome analysis by NMR and MS, respectively. We identified 38 metabolites by nuclear magnetic resonance, 37 by FIA-MS/MS, 18 by GC-MS, and 80 by LC-HRMS. The combination led us to identify a total of 132 metabolites with low variability partitioned into 58 metabolic pathways, such as amino acid, nitrogen, purine, and pyrimidine metabolism, and the citric acid cycle. This combination also showed that the contribution of GC-MS was low when used in combination with other mass spectrometry methods and nuclear magnetic resonance to explore muscle samples.

CONCLUSION

This study reports the validation of several analytical methods, based on nuclear magnetic resonance and several mass spectrometry methods, to explore the muscle metabolome from a small amount of tissue, comparable to that obtained during a clinical trial. The combination of several techniques may be relevant for the exploration of muscle metabolism, with acceptable analytical variability and overlap between methods However, the difficult and time-consuming data pre-processing, processing, and statistical analysis steps do not justify systematically combining analytical methods.

Evaluation of hand hygiene compliance and associated factors with a radio-frequency-identification-based real-time continuous automated monitoring system

BACKGROUND

Hand hygiene is a major means for preventing healthcare-associated infections. One critical point in understanding poor compliance is the lack of relevant markers used to monitor practices systematically.

METHODS

This study analysed hand hygiene compliance and associated factors with a radio-frequency-identification-based real-time continuous automated monitoring system in an infectious disease ward with 17 single bedrooms. Healthcare workers (HCWs) were tracked while performing routine care over 171 days. A multi-level multi-variate logistics model was used for data analysis. The main outcome measures were hand disinfection before entering the bedroom (outside use) and before entering the patient care zone, defined as the zone surrounding the patient's bed (inside/bedside use). Variables analysed included HCWs' characteristics and behaviour, patients, room layouts, path chains and duration of HCWs' paths.

FINDINGS

In total, 4629 paths with initial hand hygiene opportunities when entering the patient care zone were selected, of which 763 (16.5%), 285 (6.1%) and 3581 (77.4%) were associated with outside use, inside/bedside use and no use, respectively. Hand hygiene is caregiver-dependent. The shorter the duration of the HCW's path, the worse the bedside hand hygiene. Bedside hand hygiene is improved when one or two extra HCWs are present in the room.

INTERPRETATION

Hand hygiene compliance at the bedside, as analysed using the continuous monitoring system, depended upon the HCW's occupation and personal behaviour, number of HCWs, time spent in the room and (potentially) dispenser location. Meal tray distribution was a possible factor in the case of failure to disinfect hands.

Relationship between diminished ovarian reserve and mitochondrial biogenesis in cumulus cells

STUDY QUESTION

What part do mitochondria play in cases of diminished ovarian reserve (DOR)?

SUMMARY ANSWER

Mitochondrial biogenesis in cumulus cells may be linked with impaired oocyte competence in patients with DOR.

WHAT IS KNOWN ALREADY

DOR, one of the causes of infertility even in young women, is characterized by the depletion of the ovarian pool associated with a decline in oocyte competence. Mitochondria, which play a role in oocyte quality, could be involved in the pathogenesis of DOR. The study of cumulus cells offers an interesting non-invasive approach for evaluating oocyte quality and the metabolic processes on which it depends. If mitochondrial dysfunction is involved in DOR, it is likely to have an impact on the functioning of cumulus cells.

STUDY DESIGN, SIZE, DURATION

This is an observational study of 74 immature oocyte-cumulus complexes retrieved from 47 women undergoing in vitro fertilization with intracytoplasmic sperm injection at the University Hospital of Angers, France, from March 2013 to March 2014. The women were divided into two groups: one group included 26 women with DOR, and the other, which included 21 women with a normal ovarian reserve (NOR), served as a control group.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

The oocyte mitochondrial content and the average mitochondrial content of the cumulus cells were assessed by mitochondrial (mt)DNA quantification using a quantitative real-time PCR technique. Microfluidic-based quantitative RT-PCR assays were used to quantify the expression of 13 genes involved in mitochondrial functions such as apoptosis and antioxidant activity or in mitochondrial biogenesis. We used orthogonal partial least-squares discriminant analysis (OPLS-DA) to distinguish between the DOR group and the NOR group of patients, and an OPLS model to predict the value of the oocyte mtDNA content that could be used as a critical marker of oocyte quality.

MAIN RESULTS AND THE ROLE OF CHANCE

The OPLS-DA model showed a good predictive capability (Q2 = 0.543). Using the variable importance in projection (VIP) metric we found three mitochondrial variables distinguishing the DOR group from the NOR group of patients, i.e. the oocyte mtDNA content (VIP = 0.92), the cumulus cell mtDNA content (VIP = 0.95) and the expression in cumulus cells of peroxisome proliferator-activated receptor γ coactivator 1 alpha (PPARGC-1A) (VIP = 1.10), all of which were lower in the DOR group than in the NOR group of patients. The OPLS model was able to satisfactorily predict the oocyte mtDNA content in only the NOR group of patients (Q2 = 0.506). We found four new variables positively linked to the oocyte mitochondrial mass, i.e. the cumulus cell mtDNA content (VIP = 1.19), and the expression in cumulus cells of three factors of mitochondrial biogenesis: polymerase gamma (POLG) (VIP = 2.13), optic atrophy 1 (OPA1) (VIP = 1.89) and the transcription factor associated with mitochondria (TFAM) (VIP = 1.32).

LIMITATIONS, REASONS OF CAUTION

This is a descriptive study. Because of ethical concerns in human clinical practice, this study has been performed only on immature oocytes and corresponding cumulus cells, which are usually discarded during in vitro fertilization procedures.

WIDER IMPLICATIONS OF THE FINDINGS

Cumulus cells may govern mitochondrial biogenesis, creating an adequate oocyte mitochondrial pool to promote embryonic development. The alteration of this process in patients with DOR may account for the impairment of oocyte quality. This suggests that some mitochondrial characteristics of cumulus cells may serve as indicators of oocyte competence and that oocyte quality may be improved by products enhancing mitochondrial biogenesis.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by a grant from the University Hospital of Angers, France: 'Appel d'offre interne à la recherche 2014'.

TRIAL REGISTRATION NUMBER

N/A.

[Hereditary optic atrophies]

INTRODUCTION

Hereditary optic neuropathies, resulting from retinal ganglion cell degeneration, are a heterogeneous group of diseases ranging from asymptomatic forms to legal blindness.

STATE OF KNOWLEDGE

Two most frequent phenotypes are Kjer's disease, an autosomal dominant optic atrophy caused by OPA1 gene mutations, and Leber's disease due to maternally inherited mitochondrial DNA mutations.

PROSPECTS AND CONCLUSION

Both optic neuropathies usually isolated are sometimes associated with extraocular symptoms, especially neurological symptoms, thus justifying a systematic neurological evaluation and brain imaging.

Multi-system neurological disease is common in patients with OPA1 mutations

Additional neurological features have recently been described in seven families transmitting pathogenic mutations in OPA1, the most common cause of autosomal dominant optic atrophy. However, the frequency of these syndromal 'dominant optic atrophy plus' variants and the extent of neurological involvement have not been established. In this large multi-centre study of 104 patients from 45 independent families, including 60 new cases, we show that extra-ocular neurological complications are common in OPA1 disease, and affect up to 20% of all mutational carriers. Bilateral sensorineural deafness beginning in late childhood and early adulthood was a prominent manifestation, followed by a combination of ataxia, myopathy, peripheral neuropathy and progressive external ophthalmoplegia from the third decade of life onwards. We also identified novel clinical presentations with spastic paraparesis mimicking hereditary spastic paraplegia, and a multiple sclerosis-like illness. In contrast to initial reports, multi-system neurological disease was associated with all mutational subtypes, although there was an increased risk with missense mutations [odds ratio = 3.06, 95% confidence interval = 1.44-6.49; P = 0.0027], and mutations located within the guanosine triphosphate-ase region (odds ratio = 2.29, 95% confidence interval = 1.08-4.82; P = 0.0271). Histochemical and molecular characterization of skeletal muscle biopsies revealed the presence of cytochrome c oxidase-deficient fibres and multiple mitochondrial DNA deletions in the majority of patients harbouring OPA1 mutations, even in those with isolated optic nerve involvement. However, the cytochrome c oxidase-deficient load was over four times higher in the dominant optic atrophy + group compared to the pure optic neuropathy group, implicating a causal role for these secondary mitochondrial DNA defects in disease pathophysiology. Individuals with dominant optic atrophy plus phenotypes also had significantly worse visual outcomes, and careful surveillance is therefore mandatory to optimize the detection and management of neurological disability in a group of patients who already have significant visual impairment.

Mitochondrial DNA A3243G mutation involved in familial diabetes, chronic intestinal pseudo-obstruction and recurrent pancreatitis

AIMS

To report on a family with five members who carry the A3243G mutation in mitochondrial tRNA for leucine 1 (MTTL1) and present with diabetes, chronic intestinal pseudo-obstruction (CIPO) and recurrent pancreatitis, and to screen for this mutation in a cohort of 36 unrelated patients with recurrent pancreatitis.

METHODS

The mutation was quantified in several tissue samples from patients. Respiratory chain activity was studied in muscle biopsies and fibroblast cultures. In addition, the thymidine phosphorylase gene (TP) involved in mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) and three genes involved in chronic pancreatitis - PRSS1, SPINK1 and CFTR - were sequenced in affected patients. Finally, the MTTL1 gene was examined in 36 unrelated patients who had recurrent pancreatitis, but no mutations in the PRSS1 and SPINK1 genes.

RESULTS

Heteroplasmy for the mtDNA A3243G mutation was found in all tissue samples from these patients, but no mutations were found in the genes coding for thymidine phosphorylase, PRSS1, SPINK1 and CFTR. Also, none of the 36 unrelated patients with recurrent pancreatitis were carrying any MTTL1 mutations.

CONCLUSION

The mtDNA A3243G mutation associated with the gastrointestinal manifestations observed in the affected family should be regarded as a possible cause of CIPO and unexplained recurrent pancreatitis. However, the mutation is probably only weakly involved in cases of isolated recurrent pancreatitis.

Modifications in the Head Group and in the Spacer of Cholesterol-based Cationic Lipids Promote Transfection in Melanoma B16-F10 Cells and Tumours

A series of four cationic lipids derived from cholesterol was synthesised and their efficiencies to vectorise nucleic acids were compared. The investigation concerns the effects of systematic chemical modifications in the polar head and in the spacer. The cationic lipid molecules used are in the same family of 3beta[N-(N',N',N'-trimethylaminoethane)-carbamoyl] cholesterol iodide (TMAEC-Chol), presenting a spacer of two or three carbons and a quaternary ammonium polar head ramified with methyl or ethyl groups. These lipids formed stable liposomes sizing from 100 to 200 nm when prepared with the colipid dioleoyl phosphatidylethanolamine (DOPE). The goal of this work was to investigate the effect of the chemical structure of these cationic lipids on lipofection. Their ability to form complexes with DNA, their cytotoxicity and their transfection efficiency in vitro and in vivo were studied. Results were compared with those obtained from the well known cholesterol-based cationic lipid DC-Chol. In a melanoma cell line (B16-F10), results showed that either the polar head or the spacer affected the cytotoxicity. Cationic lipids with three ethyl groups in the head are more toxic than those with three methyl groups while cationic lipids with three carbons in the spacer are less toxic than those with two carbons in the spacer. The best transfection level was obtained in vitro and in vivo with cationic lipids having 3C in the spacer. Data indicated that among these lipids, in vivo gene transfer is advantaged by the methylated polar head while in vitro the best level was obtained with the ethylated one. Finally, it was observed that the chemical structure influences the transfection in the presence of serum while the complex charge and the DOPE ratios in liposomes preferentially affect the interaction with erythrocytes. Argumentations are proposed to explain the discrepancies between in vitro and in vivo transfection results concerning the optimal charge ratio and the chemical nature of the cationic lipid head group.

ADN mitochondrial du spermatozoïde

Mitochondria play a primary role in cellular energetic metabolism, homeostasis and death. In spermatozoa, in particular, mitochondria produce the ATP necessary for motility. Mitochondrial functions depend, at least partially, on mitochondrial DNA (mtDNA). The mitochondrial genome, the transmission of which is exclusively maternal contributes to cytoplasmic heredity. Qualitative and quantitative mtDNA abnormalities have been associated with male infertility. This review focuses on the role of mtDNA in human fertility.

[An OPA3 gene mutation is responsible for the disease associating optic atrophy and cataract with extrapyramidal signs]

INTRODUCTION

In 1961, Garcin et al. described a family with several members affected with optic atrophy associated with cataract, and neurological symptoms. The authors believed this condition to be distinct from other diseases known at that time, e.g. the Behr syndrome, Marinesco-Sjogren syndrome and Friedreich's ataxia.

METHOD

This family was followed over a period of 40 years and genes known to be responsible for optic atrophy were sequenced.

RESULTS

The G277A mutation of OPA3 gene was responsible for this familial disease.

DISCUSSION

A new clinical entity is identified: autosomal dominant optic atrophy and cataract, due to a heterozygous mutation of the OPA3 gene, a nuclear gene encoding a mitochondrial protein.

Low oocyte mitochondrial DNA content in ovarian insufficiency

BACKGROUND

Mitochondrial biogenesis and bioenergetics play an important role in oocyte maturation and embryo development. We have investigated the relationship between defective mitochondrial biogenesis and the lack of oocyte maturity observed during IVF procedures with patients suffering from ovarian dystrophy and ovarian insufficiency.

METHODS

We used real-time quantitative PCR to quantify mitochondrial DNA (mtDNA) in 116 oocytes obtained from 47 women undergoing the ICSI procedure. We compared the mtDNA content of oocytes from women with a normal ovarian profile with that of oocytes from women with ovarian dystrophy and ovarian insufficiency.

RESULTS

We found an average of 256,000 +/- 213,000 mitochondrial genomes per cell. The mean mtDNA copy number was not significantly different in ovarian dystrophy compared with controls, but it was significantly lower in oocytes from women with ovarian insufficiency (100,000 +/- 99,000, P < 0.0001).

CONCLUSIONS

Our results suggest that low mtDNA content is associated with the impaired oocyte quality observed in ovarian insufficiency.

A hydroxyethylated cholesterol-based cationic lipid for DNA delivery: effect of conditioning

We have synthesised a novel cholesterol-based cationic lipid to promote DNA transfer in cells. This lipid, dimethyl hydroxyethyl aminopropane carbamoyl cholesterol iodide (DMHAPC-Chol) contains a biodegradable carbamoyl linker and a hydroxyethyl group in the polar amino head moiety and is characterised by NMR. Liposomes prepared from this lipid and dioleoyl phosphatidyl ethanolamine (DOPE) in equimolar proportion showed a weak cytotoxicity as revealed by MTT assays and are efficient to deliver plasmids DNA evaluated by the expression of reporter genes in vitro and in vivo. In this paper, we present an original method to determine the lipid concentration based on the colorimetric detection of the colipid DOPE and the measure of the molar ratio DOPE/cationic lipid in the liposome by FTIR spectroscopy. The liposomes and lipid/DNA complexes structures were characterized by transmission electron microscopy (TEM) and by quasi-elastic light scattering (QLS). TEM indicated that the complexes correspond to aggregates containing globular substructures with liposomes size. The method of immuno-gold labelling was used to detect plasmid in the complex and reveals the presence of DNA inside the aggregates. Transfection results showed efficient DNA transfer depending on the charge ratio and liposomes conditioning. Gel retardation results indicated that at a molar charge ratio between X = 1.5 and X = 2.5 (depending on the liposome conditioning), all DNA was taken by liposomes. We showed that conditioning by freeze-drying (lyophilization) facilitates storage and improves transfection efficiency. When the liposomes were lyophilized prior to DNA addition or when the complexes were subjected to freeze-thawing cycles, the obtained complexes showed a transfection with levels enhanced up to four and five-fold respectively for the lyophilized liposomes and freeze-thawed complexes. NMR was used to characterize the modifications under freezing which showed an effect on 31P spectra.

In vitro embryo production efficiency in cattle and its association with oocyte adenosine triphosphate content, quantity of mitochondrial DNA, and mitochondrial DNA haplogroup

Mitochondria have a broad range of functions that affect reproduction, and structural as well as quantitative variation in mtDNA has been associated with gamete quality and reproductive success. To investigate the mitochondria effect on in vitro embryo production, we collected oocytes by ultrasound-guided follicular aspiration from donor cows known to differ in the developmental capacity, measured by the blastocyst formation rate, of their oocytes. To evaluate the potential effects of mtDNA and mitochondrial function on oocyte quality, the donor cows' mtDNA control region was sequenced and, after pairwise comparisons of polymorphisms, animals were grouped into two major haplogroups. The number of mtDNA molecules per oocyte was quantified by real-time PCR, and the adenosine triphosphate (ATP) content was measured in each oocyte to identify variations between haplogroups. Overall, ATP stocks in oocytes of the two haplogroups differed significantly (P < 0.05; means +/- SEM) both at the germinal vesicle and metaphase II stages (2.8 +/- 0.06 pmol vs. 2.6 +/- 0.07 pmol and 2.9 +/- 0.1 pmol vs. 2.3 +/- 0.06 pmol, respectively). The proportion of development to blastocyst was significantly different between haplogroups (22.3 +/- 2.1 % vs. 36.7 +/- 2.9 %). The number of mtDNA molecules per oocyte was highly variable (377 327 +/- 14 104, ranging from 2.0 x 10(3) to 1.2 x 10(6)) but not significantly different between the two haplogroups; significant differences were observed between animals without any apparent relationship to blastocyst production. These data suggest that mitochondria and mtDNA haplogroup affect the developmental capacity of bovine oocytes in vitro.

Transfer into a mesothelioma cell line of tumor suppressor gene p16 by cholesterol-based cationic lipids

In this work, the tumor suppressor gene p16 was efficiently transferred into FR cells isolated from a patient with malignant mesothelioma using cationic liposomes prepared from trimethyl aminoethane carbamoyl cholesterol (TMAEC-Chol) and triethyl aminopropane carbamoyl cholesterol (TEAPC-Chol). This transfer was performed after preliminary assays were undertaken to find the optimal transfection conditions. Results showed that an efficient transfer of plasmids containing the reporter gene pCMV-beta galactosidase vectorized by TMAEC-Chol/DOPE and TEAPC-Chol/DOPE liposomes into mesothelioma FR cells was obtained as assessed by luminometric measurements of beta-galactosidase activity. Cytotoxicity studied by MTT test showed that at concentrations used for this study, the cationic liposomes have no effect on cell growth. Transfer into mesothelioma FR cells of a plasmid construct containing the tumor suppressor gene p16 was carried out with these liposomes. Western blotting and immunofluorescence showed the presence of p16 in treated cells. An inhibition of cell growth was observed, indicating that efficient tumor suppressor gene transfer can be performed by using cationic liposomes.

Increased sperm mitochondrial DNA content in male infertility

BACKGROUND

There is increasing evidence that mitochondrial DNA (mtDNA) anomalies in sperm may lead to infertility. Point mutations, deletions and the presence of a specific mtDNA haplogroup have been associated with poor sperm quality, but little attention has been paid to the role of mtDNA content.

METHODS

Using density gradient separation and swim-up methods, we selected motile sperm from 32 normal and 35 abnormal sperm samples. The mtDNA/beta-globin gene ratio was determined by real-time quantitative PCR.

RESULTS

The average mtDNA/beta-globin ratio of sperm collected from 100% density layers was 1.4 for normal sperm, 6.1 for sperm samples presenting at least one abnormal criterion [among the three criteria established by World Health Organization (1999), i.e. sperm count, motility and morphology], and 9.1 for sperm samples presenting two or more of these abnormal criteria. These differences are very highly significant (P < 0.0001). The mtDNA numbers were also much greater in sperm collected from the 40% density gradient layers (mean: 17.1, P < 0.001), known to contain the most abnormal sperm of the sperm samples, than in those collected from the 100% layers known to contain sperm with the best fertilizing ability.

CONCLUSION

Our results showed significant mtDNA amplification in sperm collected from abnormal sperm samples.

In vitro and in vivo transfection of melanoma cells B16-F10 mediated by cholesterol-based cationic liposomes

In vitro and in vivo transgene expression in B16-F10 melanoma cells has been investigated using an original cationic liposome prepared with triethyl aminopropane carbamoyl cholesterol iodide (TEAPC-Chol) as carrier. TEAPC-Chol/DOPE (dioleoyl phosphatidyl ethanolamine) liposomes are unilamellar, very stable and not toxic in the used concentration range. The yield in complexation with plasmid DNA can reach 100% even in the presence of fetal calf serum. The transfection level has been evaluated by luminometric measurements of luciferase expression. With TEAPC-Chol/DOPE (1:1) liposomes, a relatively high transfection level in B16-F10 cells has been observed comparing to commercial reagents. For in vivo assays, the transfection level in tumors induced in Nude mice has been optimized by studying the effects of charge ratio, of the helper lipid and of the injection volume. Results showed that TEAPC-Chol/DOPE (1:1) liposomes have improved 10-fold transfection level versus direct gene transfer of free DNA.

West syndrome and mitochondrial diabetes: relationship or coincidence?

West syndrome occurs in infancy and in early childhood. It is characterized by intractable seizures occurring almost daily, severe psychomotor retardation, poor prognosis and EEG abnormalities, known as hypsarrhythmia. We report here the case of a 28-year-old patient, who was diagnosed with West syndrome when he was 8 months old and with diabetes mellitus when he was 25 years old. Sequencing analyses and restriction analyses were suggestive of mitochondrial diabetes. Four years after the diagnosis of diabetes, this patient's diabetes is still controlled by diet and biguanides.