Characterization of near-infrared spectral variance in the authentication of skim and nonfat dry milk powder collection using ANOVA-PCA, pooled-ANOVA, and partial least-squares regression.

Forty-one samples of skim milk powder (SMP) and nonfat dry milk (NFDM) from 8 suppliers, 13 production sites, and 3 processing temperatures were analyzed by NIR diffuse reflectance spectrometry over a period of 3 days. NIR reflectance spectra (1700-2500 nm) were converted to pseudoabsorbance and examined using (a) analysis of variance-principal component analysis (ANOVA-PCA), (b) pooled-ANOVA based on data submatrices, and (c) partial least-squares regression (PLSR) coupled with pooled-ANOVA. ANOVA-PCA score plots showed clear separation of the samples with respect to milk class (SMP or NFDM), day of analysis, production site, processing temperature, and individual samples. Pooled-ANOVA provided statistical levels of significance for the separation of the averages, some of which were many orders of magnitude below 10⁻³. PLSR showed that the correlation with Certificate of Analysis (COA) concentrations varied from a weak coefficient of determination (R²) of 0.32 for moisture to moderate R² values of 0.61 for fat and 0.78 for protein for this multinational study. In this study, pooled-ANOVA was applied for the first time to PLS modeling and demonstrated that even though the calibration models may not be precise, the contribution of the protein peaks in the NIR spectra accounted for the largest proportion of the variation despite the inherent imprecision of the COA values.

Exploring authentic skim and nonfat dry milk powder variance for the development of nontargeted adulterant detection methods using near-infrared spectroscopy and chemometrics.

A multinational collaborative team led by the U.S. Pharmacopeial Convention is currently investigating the potential of near-infrared (NIR) spectroscopy for nontargeted detection of adulterants in skim and nonfat dry milk powder. The development of a compendial method is challenged by the range of authentic or nonadulterated milk powders available worldwide. This paper investigates the sources of variance in 41 authentic bovine skim and nonfat milk powders as detected by NIR diffuse reflectance spectroscopy and chemometrics. Exploratory analysis by principal component analysis and varimax factor rotation revealed significant variance in authentic samples and highlighted outliers from a single manufacturer. Spectral preprocessing and outlier removal methods reduced ambient and measurement sources of variance, most likely linked to changes in moisture together with sampling, preparation, and presentation factors. Results indicate that significant chemical variance exists in different skim and nonfat milk powders that will likely affect the performance of adulterant detection methods by NIR spectroscopy.

Day 3 embryo selection by metabolomic profiling of culture medium with near-infrared spectroscopy as an adjunct to morphology: a randomized controlled trial.

STUDY QUESTION: Is the selection of a single Day 3 embryo by metabolomic profiling of culture medium with near-infrared (NIR) spectroscopy as an adjunct to morphology able to improve live birth rates in IVF, compared with embryo selection by morphology alone? SUMMARY ANSWER: The live birth rate after embryo selection by NIR spectroscopy and morphology is not significantly different compared with the live birth rate after embryos were selected by morphology alone. WHAT IS KNOWN ALREADY: The elevated incidence of pregnancy and neonatal problems associated with a high-twinning rate after IVF can only be successfully reduced by the transfer of one embryo. Current embryo assessment methods are unable to accurately predict the reproductive potential of an individual embryo. Today, a number of techniques are said to be more accurate at selecting the best embryo. One of these new technologies is metabolomic profiling of spent embryo culture media with the use of NIR spectroscopy. STUDY DESIGN, SIZE AND DURATION: A double-blind, randomized controlled trial was conducted between 2009 and 2011, and included 417 couples undergoing IVF with a single embryo transfer. Randomization was performed centrally just before Ovum Pick-Up (OPU), using a computerized randomization program. Both patient and physician were unaware of the treatment allocation. To ensure blinding, the allocations were placed in consecutively numbered, opaque envelopes. Patients were randomized (1:1) into either the control group (embryo selection by morphology only) or the treatment group (embryo selection by morphology plus NIR spectroscopy of embryo culture medium). PARTICIPANTS/MATERIALS, SETTING AND METHODS: At OPU, 208 patients were randomized to the morphology only group and 209 patients were randomized to the morphology plus viability score group. On Day 3, 163 patients in the control group and 146 patients in the treatment group met the inclusion criteria. The study was conducted in an academic hospital with IVF laboratory and three non-academic hospitals. MAIN RESULTS AND THE ROLE OF CHANCE: Patient demographics and baseline characteristics were distributed equally over the two groups, except for embryo fragmentation, which was significantly higher in the treatment group. In the intention to treat analysis, the live birth rates were 31.7 and 26.8% for the control group and the treatment group, respectively (relative risk 0.84; 95% confidence interval 0.63-1.14, P=0.27). In the per protocol analysis, the live birth rates were 31.3 and 29.5% for the control group and the treatment group, respectively (relative risk 0.94; 95% confidence interval 0.67-1.32, P=0.73). For the treatment group, the embryological technician's independent choice (by morphology) of which embryo to transfer was recorded 138 times. In 75.4% (104 of 138) of the transfers, the embryo with the best morphology did not have the highest viability score. The live birth rate of these 104 transferred embryos was 30.8%. LIMITATIONS, REASONS FOR CAUTION: A possible limitation of our study is the pre-selection of all embryos by morphology and dividing the cohort of available embryos into two groups: good quality embryos and poor quality embryos. As a consequence, we have probably selected for a better prognosis patient group. WIDER IMPLICATIONS OF THE FINDINGS: To avoid the use of incompetent embryo selection tools at the expense of the patient, an evidence-based proof of clinical usefulness is essential before the implementation of new diagnostic tools in IVF laboratories. TRIAL REGISTRATION NUMBERS: Dutch Trial Registry, registry number NTR1178.

Non-invasive viability assessment of day-4 frozen-thawed human embryos using near infrared spectroscopy.

This study investigated if metabolomic profiling of culture media using near infrared (NIR) spectroscopy was related to live-birth rates after single-embryo transfer of frozen-thawed embryos. Analysis of culture media of frozen-thawed embryos was performed by NIR spectroscopy. A viability score was calculated using a predictive multivariate algorithm of fresh day-5 embryos with known pregnancy outcomes. This algorithm generated with fresh day-5 embryos could help to identify the live-birth group from the no live-birth group. Multivariable regression models that tested the predictive ability of the viability score for live birth showed an odds ratio in the crude analysis of 1.50 (P=0.008), after adjustment for embryo morphology, 1.44 (P=0.022), and after adjustment for all variables, 1.71 (P=0.005); based on a 0.1 step increase in viability scores. In conclusion, higher viability scores resulted in higher live-birth rates. An algorithm generated from fresh embryos might be used to predict viability of frozen-thawed embryos. Frozen-thawed embryos have different metabolic activity which is related to implantation potential. Therefore, this method might be useful to select the best embryo for transfer within a group of embryos with similar morphology.

Receiver operating characteristic (ROC) analysis of day 5 morphology grading and metabolomic Viability Score on predicting implantation outcome.

PURPOSE: Assessment of embryo viability is a key component of in vitro fertilization (IVF) and currently relies largely on embryo morphology and cleavage rate. In this study, we used receiver operating characteristic (ROC) analysis to compare the Viability Score (generated by metabolomic profiling of spent embryo culture media using near infrared (NIR) spectroscopy) to morphologic grading for predicting pregnancy in women undergoing single embryo transfer (SET) on day 5. METHODS: A total of 198 spent embryo culture media samples were collected in four IVF centers located in the USA, Europe and Australia. First, 137 samples (training set) were analyzed by NIR to develop an algorithm that generates a Viability Score predictive of pregnancy for each sample. Next, 61 samples (validation set) were analyzed by observers blinded to embryo morphology and IVF outcome, using the Day 5 algorithm generated with the training set. Pregnancy was defined as fetal cardiac activity (FCA) at 12 weeks of gestation. RESULTS: The Area Under the Curve (AUC) was greater for the metabolomic Viability Score compared to Morphology [Training set: 0.75 versus 0.55, p = 0.0011; Validation set: 0.68 versus 0.50, P = 0.021], and for a Composite score (obtained using a model combining Viability Score with morphologic grading), compared to morphology alone [0.74 versus 0.50, p = 0.004]. CONCLUSIONS: Our findings suggest that Viability Score alone or in combination with morphologic grading has the potential to be a better classifier for pregnancy outcome than morphology alone in women undergoing SET on day 5.

Noninvasive metabolomic profiling as an adjunct to morphology for noninvasive embryo assessment in women undergoing single embryo transfer.

OBJECTIVE: To determine whether metabolomic profiling of spent embryo culture media correlates with reproductive potential of human embryos. DESIGN: Retrospective study. SETTING: Academic and a private assisted reproductive technology (ART) programs. PATIENT(S): Women undergoing single embryo transfer after IVF. INTERVENTION(S): Spent embryo culture media were collected after single embryo transfer on day 3 (n = 304) or day 2 (n = 181) and analyzed by near infrared spectroscopy. Near infrared spectral regions were correlated to reproductive potential using a genetic algorithm optimization. Models of these spectral regions were used to calculate viability indices, and were validated by blinded analysis of a subset (n = 60) of samples. Implantation rates were also compared between embryos of higher (>or=0.3) and lower (<0.3) viability indices, and within each morphology grade. MAIN OUTCOME MEASURE(S): Viability index and embryo viability. RESULT(S): Mean viability indices of embryos that resulted in positive fetal cardiac activity were significantly higher compared with embryos that did not for both day 2 and day 3 embryos. Blinded validation of the day 2 model proved to be significant. Increasing viability index values correlated with an increase in pregnancy. Viability indices were found to be independent of morphology for both day 2 and day 3 embryos. Implantation rates were significantly higher among embryos with viability indices >or=0.3. CONCLUSION(S): Metabolomic profiling of human embryo culture media using near infrared spectroscopy is independent of morphology and correlates with reproductive potential of embryos.

Metabolomic assessment of oocyte viability.

The aim of the current study was to evaluate whether near-infrared (NIR) spectroscopy-generated metabolomic data obtained from oocyte culture samples would correlate with nuclear maturity status and derived embryo development. A total of 412 oocyte culture samples were collected from 43 patient cycles. Metabolomic profiles of metaphase I and II oocytes were obtained by NIR spectroscopy and were significantly different from each other and from profiles of prophase I (germinal vesicle) oocytes (P +/- 0.001 at the 95% confidence interval). Additionally, NIR spectroscopic analysis of culture medium of oocytes that developed to grade A embryos on day 3 demonstrated significantly higher viability indices (0.62 +/- 0.23) than those that developed to grades C/D (0.42 +/- 0.26; P < 0.006); and on day 5 grade A (0.37 +/- 0.20) was also higher than grades C/D (0.14 +/- 0.21; P < 0.02). Metabolomic profiles of oocytes that resulted in pregnancy had higher viability indices (0.87 +/- 0.27) than those that did not (0.44 +/- 0.17; P < 0.0001). The results of the current study demonstrate that metabolomic profiling from spent culture medium of the oocyte is related to nuclear maturity, is able to predict embryo development at day 3 and day 5 stages, and relates to embryo viability.

Noninvasive metabolomic profiling of embryo culture media using proton nuclear magnetic resonance correlates with reproductive potential of embryos in women undergoing in vitro fertilization.

OBJECTIVE: To identify biomarkers associated with reproductive outcome using proton nuclear magnetic resonance ((1)H NMR) metabolomic profiling of embryo culture media. DESIGN: Retrospective study. SETTING: An academic assisted reproductive technology (ART) program; a university research center. PATIENT(S): Women undergoing ART treatment. INTERVENTION(S): Spent media samples from embryos that resulted in pregnancy and delivery (n = 17) and samples (n = 17) from embryos that failed to implant were individually collected on day 3, and evaluated using (1)H NMR spectroscopy. The spectra obtained were quantified by integrating six biomarker signals in the aliphatic region after baseline subtraction. Using a multivariate analysis, a model that calculates a viability index for each spectrum was developed. Sensitivity and specificity of predicting pregnancy (described as implantation and delivery) were calculated. MAIN OUTCOME MEASURE(S): The (1)H NMR metabolomic profile of embryo culture media and embryo viability. RESULT(S): Glutamate concentrations determined by (1)H NMR were significantly higher in spent culture media of embryos that resulted in pregnancy and delivery compared to those that failed to implant. Similarly, viability indices calculated by (1)H NMR using the weighted coefficients of glutamate and alanine/lactate ratio quantities were higher for embryos that implanted and resulted in a delivery. Proton NMR spectroscopy predicted viability of individual embryos with a sensitivity of 88.2% and a specificity of 88.2%. CONCLUSION(S): Metabolomic profile of spent embryo culture media using (1)H NMR correlates with the reproductive potential of embryos.

Metabolomics and its application for non-invasive embryo assessment in IVF.

Morphology and cleavage rate remain the mainstay of embryo assessment. However, a number of additional technologies for this application are under investigation. These include the measurement of glucose, lactate, pyruvate or amino acid levels in the embryo culture media, assessment of oxygen consumption by the embryo, genomic and proteomic profiling, and most recently, analytical examination of the embryonic metabolome. As the number of assisted reproduction cycles increases worldwide, improvements in the ability to quickly and non-invasively identify the best embryos for transfer remain a critical goal for reproductive medicine. Recent studies suggest that metabolomic profiling of embryo culture media using optical and non-optical spectroscopies may provide a useful adjunct to the current embryo assessment strategies and provide insight into the phenotype of embryos with increasing reproductive potential.