Ultra high field NMR spectroscopic studies on human seminal fluid, seminal vesicle and prostatic secretions

Rats Orally Administered with Ethyl Alcohol for a Prolonged Time Show Histopathology of the Epididymis and Seminal Vesicle Together with Changes in the Luminal Metabolite Composition

Prolonged ethanol (EtOH) consumption is associated with male infertility, with a decreased spermatogenesis rate as one cause. The defective maturation and development of sperm during their storage in the cauda epididymis and transit in the seminal vesicle can be another cause, possibly occurring before the drastic spermatogenesis disruption. Herein, we demonstrated that the cauda epididymis and seminal vesicle of rats, orally administered with EtOH under a regimen in which spermatogenesis was still ongoing, showed histological damage, including lesions, a decreased height of the epithelial cells and increased collagen fibers in the muscle layer, which implicated fibrosis. Lipid peroxidation (shown by malondialdehyde (MDA) levels) was observed, indicating that reactive oxygen species (ROS) were produced along with acetaldehyde during EtOH metabolism by CYP2E1. MDA, acetaldehyde and other lipid peroxidation products could further damage cellular components of the cauda epididymis and seminal vesicle, and this was supported by increased apoptosis (shown by a TUNEL assay and caspase 9/caspase 3 expression) in these two tissues of EtOH-treated rats. Consequently, the functionality of the cauda epididymis and seminal vesicle in EtOH-treated rats was impaired, as demonstrated by a decreases in 1H NMR-analyzed metabolites (e.g., carnitine, fructose), which were important for sperm development, metabolism and survival in their lumen.

Integrative Molecular Structure Elucidation and Construction of an Extended Metabolic Pathway Associated with an Ancient Innate Immune Response in COVID-19 Patients

We present compelling evidence for the existence of an extended innate viperin-dependent pathway, which provides crucial evidence for an adaptive response to viral agents, such as SARS-CoV-2. We show the in vivo biosynthesis of a family of novel endogenous cytosine metabolites with potential antiviral activities. Two-dimensional nuclear magnetic resonance (NMR) spectroscopy revealed a characteristic spin-system motif, indicating the presence of an extended panel of urinary metabolites during the acute viral replication phase. Mass spectrometry additionally enabled the characterization and quantification of the most abundant serum metabolites, showing the potential diagnostic value of the compounds for viral infections. In total, we unveiled ten nucleoside (cytosine- and uracil-based) analogue structures, eight of which were previously unknown in humans allowing us to propose a new extended viperin pathway for the innate production of antiviral compounds. The molecular structures of the nucleoside analogues and their correlation with an array of serum cytokines, including IFN-α2, IFN-γ, and IL-10, suggest an association with the viperin enzyme contributing to an ancient endogenous innate immune defense mechanism against viral infection.

Application of response surface methodology and quantitative NMR for the optimum extraction, characterization, and quantitation of Antrodia cinnamomea triterpenoids

Antrodia cinnamomea (AC) is a treasured Asian medicinal mushroom, which has attracted attention due to recent research on its effectiveness in targeting a variety of serious ailments such as cancer and liver diseases. Among different A. cinnamomea constituents, triterpenoids are regarded as the most therapeutically attractive components because of their anti-inflammatory and cytotoxic activities. In the present study, we proposed a mathematical and statistical extraction protocol to evaluate the concentrations of total ergostane and lanostane triterpenoid derivatives from the ethanolic extract of the wild fruiting bodies of A. cinnamomea (EEAC) by utilizing response surface methodology (RSM) and quantitative NMR (qNMR) approaches. The optimum response surface model showed that the variations of the investigated response variables reached more than 90%, suggesting that the developed model is accurate in explaining response variability. Furthermore, the EEAC major characteristic triterpenoids were quantified through the comparison of the HPLC-tandem MS results with those of the qNMR results. The precision of the used techniques was also evaluated. The experimental design of the EEAC optimum extraction procedure obtained by using RSM and qNMR enabled accurate characterization and quantitation of A. cinnamomea triterpenoids.

A different approach to the quantification of human seminal plasma metabolites using high-resolution NMR spectroscopy

In this study, a reliable method was established for the absolute quantification of metabolite concentrations in human seminal plasma using ERETIC2, a quantification tool developed by Bruker based on the PULCON principle. The performance of the ERETIC2 was examined using an AVANCE III HD NMR spectrometer (600 MHz) equipped with a triple inverse 1.7 mm TXI probe in terms of some experimental parameters that may affect the accuracy and precision of the quantitative results. Then, the accuracy, precision, and repeatibility of ERETIC2 were determined using L-asparagine solutions at different concentrations. And it was evaluated by comparing it with the classical internal standard (IS) quantification method. The relative standard deviation (RSD) values for ERETIC2 were calculated in the range of 0.55-1.90% and the minimum recovery value was 99.9%, while the RSD values for the IS method were calculated in the range of 0.88-5.83% and recovery value was minimum 91.0%. Besides, the RSD values of the inter-day precisions for the ERETIC2 and IS methods were obtained to be in the range of 1.25 - 3.03% and 0.97 - 3.46%, respectively. Finally, the concentration values of seminal plasma metabolites were determined using different pulse programs with both methods for samples obtained from normozoospermic control and azoospermic patient groups. The results proved that this quantification method developed using NMR spectroscopy is easy to use in complex sample systems such as biological fluids and is a good alternative to the classical internal standard method in terms of accuracy and sensitivity. In addition, the improvement of the spectral resolution and sensitivity with the microcoil probe technology and the possibility of analyzing with minimum sample quantities has contributed positively to the results of this method.

Metabolite interactions in prostatic fluid mimics assessed by 1H NMR

INTRODUCTION

Molecular interactions in prostatic fluid are of biological interest and may affect MRI and MRS of the prostate. We investigated the existence of interactions between the major components of this fluid: spermine, citrate and myoinositol, metal ions, including zinc, and proteins.

MATERIALS AND METHODS

Solutions of 90 mM citrate, 18 mM spermine and 6 mM myo-inositol, mimicking expressed prostatic fluid, were investigated by 1H NMR using changes in T2 relaxation and chemical shift as markers for interactions.

RESULTS AND DISCUSSION

Adding to this metabolite mixture the ions Na⁺ , K⁺, Ca⁺⁺, Mg⁺⁺ and Zn⁺⁺, decreased the T2 relaxation times of citrate and spermine protons by factors of 3 and 2, respectively, with Zn++ causing the largest effect, indicating ion-metabolite interactions. The T2 of 18 mM spermine dropped by a factor of 2 upon addition with 90 mM citrate, but no effect on T2 was seen with myo-inositol pointing to a specific citrate-spermine interaction. Moreover, the T2 of citrate in the presence of spermine decreased by adding metal ions and increasing amounts of Zn⁺⁺, indicating complexation of citrate and spermine with metal ions, particularly with Zn. The addition of bovine serum albumin (BSA), as an index protein, substantially further decreased the T2 of spermine and citrate implying the formation of a transient spermine-metal ion-citrate-BSA complex. Finally, we found that the T2 of citrate in extracellular fluid of prostate cancer cells, as a mimic of fluid in cancerous prostates, decreased by adding fetal calf serum, indicating protein binding.

Potential of nuclear magnetic resonance metabolomics in the study of prostate cancer

Nuclear magnetic resonance (NMR) metabolomics is a powerful analytical technique and a tool which has unique characteristics and capabilities for the evaluation of a number of biochemicals/metabolites of cancer and other disease processes that are present in biofluids (urine and blood) and tissues. The potential of NMR metabolomics in prostate cancer (PCa) has been explored by researchers and its usefulness has been documented. A large number of metabolites such as citrate, choline, and sarcosine were detected by NMR metabolomics from biofluids and tissues related to PCa and their levels were compared with controls and benign prostatic hyperplasia. The changes in the levels of these metabolites aid in the diagnosis and help to understand the dysregulated metabolic pathways in PCa. We review recent studies on in vitro and ex vivo NMR spectroscopy-based PCa metabolomics and its possible role as a diagnostic tool.

Seminal plasma metabolomics profiles following long (4-7 days) and short (2 h) sexual abstinence periods

OBJECTIVE

Metabolomic profiling of seminal plasma has been suggested as a possible approach for a fast and non-invasive male infertility evaluation diagnosis. However, metabolomics profiles in normozoospermic men have not been thoroughly investigated, and the influence of ejaculation-abstinence has not been described. To provide interim reference values and find associations between the metabolomics profiles of human seminal plasma and length of ejaculation-abstinence period in normozoospermic men.

STUDY DESIGN

Semen samples collected after long (4-7 days) and short abstinence (2 h) from 31 normozoospermic males were assessed for routine quality parameters before the seminal plasma was separated by centrifugation. Metabolomics profiles of the seminal plasma were then determined using untargeted Nuclear Magnetic Resonance Spectroscopy.

RESULTS

In total, 30 metabolites were identified. Pyruvate showed a higher concentration, while fructose, acetate, choline, methanol, N-acetylglucosamine, O-acetylcarnitine, uridine, and sn-glycero-3-phosphocoline showed lower concentrations in samples collected after short abstinence (vs. long). All metabolites showed lower absolute amounts (volume × concentration) following shorter abstinence. However, the lower sperm concentration in samples collected after short abstinence resulted in higher absolute amounts of pyruvate and taurine per spermatozoa: pyruvate 1.92 (1.12-3.87) vs. 1.29 (0.83-2.62) (P < 0.001) and taurine 0.58 (0.36-0.92) vs. 0.43 (0.28-0.95) (P < 0.05) ng/10⁶ spermatozoa. Simultaneously, there was a higher percentage of progressively motile spermatozoa in samples collected after the short abstinence.

CONCLUSION

The generally lower concentrations of seminal metabolites after short abstinence periods may be related to the shorter time available for secretion and collection of these metabolites by the accessory glands and the epididymides. The concomitant lower number of spermatozoa in the second ejaculate resulted in increased absolute amounts of pyruvate and taurine per spermatozoa, accompanied by increased spermatozoa motility in these samples. The simultaneous increase in percentages of motile spermatozoa and absolute amounts of pyruvate and taurine per spermatozoa after shorter abstinence might indicate that these two metabolites play a more critical role in sperm motility, which should be further investigated in future studies.

Relationships between Seminal Plasma Metabolites, Semen Characteristics and Sperm Kinetics in Donkey (Equus asinus)

Simple Summary

A deeper knowledge of reproductive biology may be helpful in the donkey to avoid the risk of extinction that some breeds are facing. The evaluation of metabolites in seminal plasma provides crucial information for the knowledge of donkey sperm metabolism, for obtaining comparative information with other species, as well as for providing useful elements for the formulation of extenders for sperm dilution and conservation. Moreover, correlations of seminal metabolites with sperm kinetics highlight new possible markers of sperm quality. Using multivariate analysis, all metabolic, seminal, and spermatic data were merged in a single dot that grouped individual stallions within clusters in the Cartesian axes according to the different spermatic characteristics. This amount of information also allows to shed light on the effects of total or partial removal of seminal plasma for improving sperm preservation. The inclusion in the study of an azoospermic individual represents a further discriminating element in the analysis of sperm quality under physiological and pathological conditions.

Abstract

This study aimed to evaluate donkey seminal plasma metabolites and relate this information to the main characteristics of sperm quality. Sperm kinetics from 10 donkey stallions were analyzed with a computerized system at the time of collection (T0) and after 24 h storage at 4 °C (T24). Seminal plasma was frozen at −80 °C for subsequent proton nuclear magnetic resonance (¹H NMR) spectroscopy. On three stallions, semen collection was repeated monthly for three times and sperm analysis also included mitochondrial activity and oxidative status. One stallion was azoospermic and a second semen collection was performed after one month. In the seminal plasma, 17 metabolites were identified; their levels showed numerous significant variations between the azoospermic and the normospermic individuals and grouped in well-defined clusters in a multivariate analysis. Comparing individuals with high and low sperm motility, the only discriminating metabolite was phenylalanine, whose levels were lower in the latter, as in the azoospermic individual. Phenylalanine was also the only metabolite highly correlated with all sperm kinematic parameters at T24. In conclusion, the present study has provided relevant information on the chemical characteristics of donkey semen, identified relationships between seminal metabolites, semen parameters, and sperm kinetics, and offered insights for future technological applications.

The utility of nuclear magnetic resonance spectroscopy in assisted reproduction

Infertility affects approximately 15-20% of individuals of reproductive age worldwide. Over the last 40 years, assisted reproductive technology (ART) has helped millions of childless couples. However, ART is limited by a low success rate and risk of multiple gestations. Devising methods for selecting the best gamete or embryo that increases the ART success rate and prevention of multiple gestation has become one of the key goals in ART today. Special emphasis has been placed on the development of non-invasive approaches, which do not require perturbing the embryonic cells, as the current morphology-based embryo selection approach has shortcomings in predicting the implantation potential of embryos. An observed association between embryo metabolism and viability has prompted researchers to develop metabolomics-based biomarkers. Nuclear magnetic resonance (NMR) spectroscopy provides a non-invasive approach for the metabolic profiling of tissues, gametes and embryos, with the key advantage of having a minimal sample preparation procedure. Using NMR spectroscopy, biologically important molecules can be identified and quantified in intact cells, extracts or secretomes. This, in turn, helps to map out the active metabolic pathways in a system. The present review covers the contribution of NMR spectroscopy in assisted reproduction at various stages of the process.

1H Nuclear Magnetic Resonance of Pig Seminal Plasma Reveals Intra-Ejaculate Variation in Metabolites

In pigs, ejaculate is expelled in fractions, mainly the sperm-rich fraction (SRF) and the post-SRF (PSRF), which differ in both sperm content and origin. In addition, intra-ejaculate variability between fractions in terms of sperm reproductive characteristics has been previously reported, the highest sperm quality being observed in the first 10 mL of the SRF (SRF-P1). As seminal plasma (SP) composition has been purported to influence sperm physiology, the aim of this study was to profile pig SP metabolite composition and to find putative differences between the ejaculate portions (SRF-P1, the rest of SRF [SRF-P2], PSRF) and entire ejaculate (EE). To this end, ejaculates (n = 8, one per boar) were collected in fractions and SP was analyzed using 1H Nuclear Magnetic Resonance spectroscopy. We identified 19 metabolites present in all ejaculate portions and the EE, and reported correlations between the metabolites. Additionally, and for the first time in mammals, we found intra-ejaculate variability in the SP metabolites, observing different relative abundances in choline, glycerophosphocholine and glycine. Regarding their influence in sperm physiology, we hypothesize that these metabolites may explain the specific reproductive characteristics of each ejaculate portion. Finally, the reported SP metabolites could serve as a first steppingstone in the study of quality, functionality, and fertility biomarkers.

Metabolomics technology and bioinformatics for precision medicine

Precision medicine is rapidly emerging as a strategy to tailor medical treatment to a small group or even individual patients based on their genetics, environment and lifestyle. Precision medicine relies heavily on developments in systems biology and omics disciplines, including metabolomics. Combination of metabolomics with sophisticated bioinformatics analysis and mathematical modeling has an extreme power to provide a metabolic snapshot of the patient over the course of disease and treatment or classifying patients into subpopulations and subgroups requiring individual medical treatment. Although a powerful approach, metabolomics have certain limitations in technology and bioinformatics. We will review various aspects of metabolomics technology and bioinformatics, from data generation, bioinformatics analysis, data fusion and mathematical modeling to data management, in the context of precision medicine.

DQF J-RES NMR: Suppressing the singlet signals for improving the J-RES spectra from complex mixtures

Two-dimensional J-RESolved spectroscopy (J-RES) finds routine use in metabolomics for reducing signal overlap as it separates chemical shift and multiplet information along two frequency axes. However, only magnitude mode of the experiment is practical which prevents exploitation of its full resolving power. Tailing from high-intensity metabolite peaks often obscure nearby low-intensity metabolite peaks which leads to ambiguity in assignment of metabolites. Absorptive mode J-RES spectroscopy offers better-resolving power but comes at the cost of either sensitivity or complicated post-processing. Quite often for certain complex mixtures such as bio-fluids some components of the mixture display intense singlet signals which dominate the whole spectrum resulting in less reliable detection of weaker metabolite signals. Multi-frequency presaturation could suppress these intense singlets but will also remove the useful weaker multiplet peaks which are either totally eclipsed with the intense singlets or very close in frequency. We show that by using a double quantum filter (DQF) in magnitude mode J-RES technique, the intensity of the strong singlet metabolite peaks can be reduced relative to the intensity of the sparsely present multiplet metabolite signals. This approach leads to the identification of many weak intensity multiplet peaks which are otherwise undetected due to their overlap with intense singlet peaks in regular J-RES as well as 1D ¹H spectra. Although the improved intensity of most of the weaker peaks relative to the strong singlet peaks is observed, some multiplets can disappear due to the delay-dependent modulation of the signals by the DQF. A few DQF J-RES spectra recorded with different DQF delays, therefore, produce better assignment when analyzed together. The technique is demonstrated on a mixture of eight compounds, human urine, and plant extract samples.

1H Magnetic Resonance Spectroscopy of live human sperm

STUDY QUESTION

Can ¹H Magnetic Resonance Spectroscopy (MRS) be used to obtain information about the molecules and metabolites in live human spermatozoa?

SUMMARY ANSWER

Percoll-based density gradient centrifugation (DGC) followed by a further two washing steps, yielded enough sperm with minimal contamination (<0.01%) from seminal fluid to permit effective MRS which detected significant differences (P < 0.05) in the choline/glycerophosphocholine (GPC), lipid and lactate regions of the ¹H MRS spectrum between sperm in the pellet and those from the 40%/80% interface.

WHAT IS KNOWN ALREADY

Current methods to examine sperm are either limited in their value (e.g. semen analysis) or are destructive (e.g. immunohistochemistry, sperm DNA testing). A few studies have previously used MRS to examine sperm, but these have either looked at seminal plasma from men with different ejaculate qualities or at the molecules present in pooled samples of lyophilized sperm.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

Sperm suspended in phosphate buffered saline (PBS) at 37°C were examined by ¹H MRS scanning using a ¹H excitation-sculpting solvent suppression sequence after recovery from fresh ejaculates by one of three different methods: (i) simple centrifugation; (ii) DGC with one wash; or (iii) DGC with two washes. In the case of DGC, sperm were collected both from the pellet (‘80%’ sperm) and the 40/80 interface (‘40%’ sperm). Spectrum processing was carried out using custom Matlab scripts to determine; the degree of seminal plasma/Percoll contamination, the minimum sperm concentration for ¹H MRS detection and differences between the ¹H MRS spectra of ‘40%’ and ‘80%’ sperm.

MAIN RESULTS AND THE ROLE OF CHANCE

DGC with two washes minimized the ¹H MRS peak intensity for both seminal plasma and Percoll/PBS solution contamination while retaining sperm specific peaks. For the MRS scanner used in this study, the minimum sperm concentration required to produce a choline/GPC ¹H MRS peak greater than 3:1 signal to noise ratio (SNR) was estimated at ~3 × 10⁶/ml. The choline/GPC and lactate/lipid regions of the ¹H spectrum were significantly different by two-way ANOVA analysis (P < 0.0001; n = 20). ROC curve analysis of these region showed significant ability to distinguish between the two sperm populations: choline/GPC ROC AUC = 0.65–0.67, lactate/lipid ROC AUC = 0.86–0.87.

LIMITATIONS, REASONS FOR CAUTION

Only 3–4 semen samples were used to assess the efficacy of each sperm washing protocol that were examined. The estimated minimum sperm concentration required for MRS is specific to the hardware used in our study and may be different in other spectrometers. Spectrum binning is a low resolution analysis method that sums MRS peaks within a chemical shift range. This can obscure the identity of which metabolite(s) are responsible for differences between sperm populations. Further work is required to determine the relative contribution of somatic cells to the MRS spectrum from the ‘40%’ and ‘80%’ sperm.

WIDER IMPLICATIONS OF THE FINDINGS

¹H MRS can provide information about the molecules present in live human sperm and may therefore permit the study of the underlying functional biology or metabolomics of live sperm. Given the relatively low concentration of sperm required to obtain a suitable MRS signal (~3 × 10⁶/ml), this could be carried out on sperm from men with oligo-, astheno- or teratozoospermia. This may lead to the development of new diagnostic tests or ultimately novel treatments for male factor infertility.

STUDY FUNDING AND COMPETING INTEREST(S)

This work was supported by the Medical Research Council Grant MR/M010473/1. The authors declare no conflicts of interest.

Ex vivo metabolic fingerprinting identifies biomarkers predictive of prostate cancer recurrence following radical prostatectomy

Background:

Robust biomarkers that identify prostate cancer patients with high risk of recurrence will improve personalised cancer care. In this study, we investigated whether tissue metabolites detectable by high-resolution magic angle spinning magnetic resonance spectroscopy (HR-MAS MRS) were associated with recurrence following radical prostatectomy.

Methods:

We performed a retrospective ex vivo study using HR-MAS MRS on tissue samples from 110 radical prostatectomy specimens obtained from three different Norwegian cohorts collected between 2002 and 2010. At the time of analysis, 50 patients had experienced prostate cancer recurrence. Associations between metabolites, clinicopathological variables, and recurrence-free survival were evaluated using Cox proportional hazards regression modelling, Kaplan–Meier survival analyses and concordance index (C-index).

Results:

High intratumoural spermine and citrate concentrations were associated with longer recurrence-free survival, whereas high (total-choline+creatine)/spermine (tChoCre/Spm) and higher (total-choline+creatine)/citrate (tChoCre/Cit) ratios were associated with shorter time to recurrence. Spermine concentration and tChoCre/Spm were independently associated with recurrence in multivariate Cox proportional hazards modelling after adjusting for clinically relevant risk factors (C-index: 0.769; HR: 0.72; P=0.016 and C-index: 0.765; HR: 1.43; P=0.014, respectively).

Conclusions:

Spermine concentration and tChoCre/Spm ratio in prostatectomy specimens were independent prognostic markers of recurrence. These metabolites can be noninvasively measured in vivo and may thus offer predictive value to establish preoperative risk assessment nomograms.

NMR and MS Methods for Metabolomics

Metabolomics, also often referred as "metabolic profiling," is the systematic profiling of metabolites in biofluids or tissues of organisms and their temporal changes. In the last decade, metabolomics has become more and more popular in drug development, molecular medicine, and other biotechnology fields, since it profiles directly the phenotype and changes thereof in contrast to other "-omics" technologies. The increasing popularity of metabolomics has been possible only due to the enormous development in the technology and bioinformatics fields. In particular, the analytical technologies supporting metabolomics, i.e., NMR, UPLC-MS, and GC-MS, have evolved into sensitive and highly reproducible platforms allowing the determination of hundreds of metabolites in parallel. This chapter describes the best practices of metabolomics as seen today. All important steps of metabolic profiling in drug development and molecular medicine are described in great detail, starting from sample preparation to determining the measurement details of all analytical platforms, and finally to discussing the corresponding specific steps of data analysis.

MR Spectroscopy in Prostate Cancer: New Algorithms to Optimize Metabolite Quantification

Prostate cancer (PCa) is the most common non-cutaneous cancer in male subjects and the second leading cause of cancer-related death in developed countries. The necessity of a non-invasive technique for the diagnosis of PCa in early stage has grown through years. Proton magnetic resonance spectroscopy (1H-MRS) and proton magnetic resonance spectroscopy imaging (1H-MRSI) are advanced magnetic resonance techniques that can mark the presence of metabolites such as citrate, choline, creatine and polyamines in a selected voxel, or in an array of voxels (in MRSI) inside prostatic tissue. Abundance or lack of these metabolites can discriminate between pathological and healthy tissue. Although the use of magnetic resonance spectroscopy (MRS) is well established in brain and liver with dedicated software for spectral analysis, quantification of metabolites in prostate can be very difficult to achieve, due to poor signal to noise ratio and strong J-coupling of the citrate. The aim of this work is to develop a software prototype for automatic quantification of citrate, choline and creatine in prostate. Its core is an original fitting routine that makes use of a fixed step gradient descent minimization algorithm (FSGD) and MRS simulations developed with the GAMMA libraries in C++. The accurate simulation of the citrate spin systems allows to predict the correct J-modulation under different NMR sequences and under different coupling parameters. The accuracy of the quantifications was tested on measurements performed on a Philips Ingenia 3T scanner using homemade phantoms. Some acquisitions in healthy volunteers have been also carried out to test the software performance in vivo.

NMR-based metabolomics of prostate cancer: a protagonist in clinical diagnostics

Advances in the application of NMR spectroscopy-based metabolomic profiling of prostate cancer comprises a potential tactic for understanding the impaired biochemical pathways arising due to a disease evolvement and progression. This technique involves qualitative and quantitative estimation of plethora of small molecular weight metabolites of body fluids or tissues using state-of-the-art chemometric methods delivering an important platform for translational research from basic to clinical, to reveal the pathophysiological snapshot in a single step. This review summarizes the present arrays and recent advancements in NMR-based metabolomics and a glimpse of currently used medical imaging tactics, with their role in clinical diagnosis of prostate cancer.

Discrimination of human semen specimens by NMR data, sperm parameters, and statistical analysis

Human seminal fluid is a complex mixture of secretions originated from epididymis and the male accessory sex glands. It contains a variety of both inorganic and organic components, among which proteins are a major part of the high molecular-mass substances. In this study, 83 human seminal plasma samples were analyzed using a combined Nuclear Magnetic Resonance (NMR) Spectroscopy and Principal Component Analysis (PCA) approach to discriminate patients in relation to semen characteristics and/or conditions affecting the fertility status. Results showed a discrimination between patients with leukocytospermia and with the concomitant presence of varicocele/ex varicocele and leukocytospermia. Patients with testicular cancer, necrozoospermia, and azoospermia were separated from the other patient clusters. In addition, a differentiation of semen quality was also possible. This study represents to first use of sperm parameters together with NMR data as variables in the PCA analysis. Furthermore, this methodology allows the identification of the metabolites which play the most important role in identifying differences among human seminal plasma samples.

Identification of biochemical differences between different forms of male infertility by nuclear magnetic resonance (NMR) spectroscopy

PURPOSE

The aim of this study was to analyze the seminal plasma of patients with idiopathic/male factor infertility and healthy controls with proven fertility by NMR spectroscopy, with a hope of establishing difference in biomarker profiles, if any, between the groups.

METHODS

A total of 103 subjects visiting the infertility clinic of Manipal University with normozoospermic parameters, oligozoospermia, asthenozoospermia, azoospermia and teratozoospermia were included. Semen characteristics were analysed by standard criteria. Seminal plasma was subjected to NMR spectroscopy at a 700 MHz (1)H frequency. The resultant data was analyzed by appropriate software.

RESULTS

The analysis revealed significant differences between the fertile control group and other forms of male infertility. Interestingly, seminal plasma profile of the idiopathic infertility group showed distinct segregation from the control population as well as other infertile groups. The difference in biomarker profiles between the idiopathic infertility and the rest of the groups combined could originate from either the up-regulation or down regulation of a several compounds, including lysine, arginine, tyrosine, citrate, proline and fructose.

CONCLUSION

Our data suggests the presence of a metabolic reason behind the origin of idiopathic infertility. (1)H NMR based metabonomic profiling based on concentration of biomarker lysine has the potential to aid in the detection and diagnosis of idiopathic infertility in an efficient manner.

Magnetic susceptibility to measure total protein concentration from NMR metabolite spectra: Demonstration on blood plasma

PURPOSE

Accurate metabolite and protein quantification in blood plasma and other body fluids from one single NMR measurement, allowing for improved quantitative metabolic profiling and better assessment of metabolite-protein interactions.

THEORY AND METHODS

The total protein concentration is derived from the common chemical-shift changes-caused by protein-induced bulk magnetic susceptibility (BMS)-measured on well-accessible and exchange-free metabolite resonances. These BMS shifts are simply obtained by external referencing with respect to 3-(trimethylsilyl)propionic-2,2,3,3-d4 acid, sodium salt in a coaxial insert.

RESULTS

Based on blood-plasma data from five volunteers, the estimated accuracy of the BMS method is ≤ 5% with respect and comparable to the 3.8% error of the standard colorimetric, Biuret, method. Valine, alanine, glucose, leucine, and lactate display no exchange-induced shift changes. Their well-accessible signals act as reliable probes for pure protein-induced BMS. The slopes and intercepts of their chemical-shift change versus protein concentration were derived from metabolite mixtures with (fatted) human and bovine albumin acting as blood-plasma mimics.

CONCLUSION

The BMS method, demonstrated on blood plasma, can also be used on other samples containing sufficient protein (> 10 g/L). Also, it allows measurement of the presence and sign of exchange-induced chemical-shift changes.

Metabolite ratios in 1H MR spectroscopic imaging of the prostate

In (1)H MR spectroscopic imaging ((1)H-MRSI) of the prostate the spatial distribution of the signal levels of the metabolites choline, creatine, polyamines, and citrate are assessed. The ratio of choline (plus spermine as the main polyamine) plus creatine over citrate [(Cho+(Spm+)Cr)/Cit] is derived from these metabolites and is used as a marker for the presence of prostate cancer. In this review, the factors that are of importance for the metabolite ratio are discussed. This is relevant, because the appearance of the metabolites in the spectrum depends not only on the underlying anatomy, metabolism, and physiology of the tissue, but also on acquisition parameters. These parameters influence especially the spectral shapes of citrate and spermine resonances, and consequently, the (Cho+(Spm+)Cr)/Cit ratio. Both qualitative and quantitative approaches can be used for the evaluation of (1)H-MRSI spectra of the prostate. For the quantitative approach, the (Cho+(Spm+)Cr)/Cit ratio can be determined by integration or by a fit based on model signals. Using the latter, the influence of the acquisition parameters on citrate can be taken into account. The strong overlap between the choline, creatine, and spermine resonances complicates fitting of the individual metabolites. This overlap and (unknown, possibly tissue-related) variations in T1, T2, and J-modulation hamper the application of corrections needed for a "normalized" (Cho+(Spm+)Cr)/Cit ratio that would enable comparison of spectra measured with different prostate MR spectroscopy protocols. Quantitative (Cho+(Spm+)Cr)/Cit thresholds for the evaluation of prostate cancer are therefore commonly established per institution or per protocol. However, if the same acquisition and postprocessing protocol were used, the ratio and the thresholds would be institution-independent, promoting the clinical usability of prostate (1)H-MRSI.

High-resolution NMR spectroscopy of human body fluids and tissues in relation to prostate cancer

High-resolution NMR spectroscopic studies of prostate tissue extracts, prostatic fluid, seminal fluid, serum and urine can be used for the detection of prostate cancer, based on the differences in their metabolic profiles. Useful diagnostic information is obtained by the detection or quantification of as many metabolites as possible and comparison with normal samples. Only a few studies have shown the potential of high-resolution in vitro NMR of prostate tissues. A survey of the literature has revealed that studies on body fluids, such as urine and serum, in relation to prostate cancer are rare. In addition, the potential of NMR of nuclei other than (1)H, such as (13)C and (31)P, has not been exploited fully. The metabolomic analysis of metabolites, detected by high-resolution NMR, may help to identify metabolites which could serve as useful biomarkers for prostate cancer detection. Such NMR-derived biomarkers would not only help in prostate cancer detection and in understanding the in vivo MRS metabolic profile, but also to investigate the biochemical and metabolic changes associated with cancer. Here, we review the published research work on body fluids in relation to prostate and prostate tissue extracts, and highlight the potential of such studies for future work.

Mapping of prostate cancer by 1H MRSI

In many studies, it has been demonstrated that (1)H MRSI of the human prostate has great potential to aid prostate cancer management, e.g. in the detection and localisation of cancer foci in the prostate or in the assessment of its aggressiveness. It is particularly powerful in combination with T2 -weighted MRI. Nevertheless, the technique is currently mainly used in a research setting. This review provides an overview of the state-of-the-art of three-dimensional MRSI, including the specific hardware required, dedicated data acquisition sequences and information on the spectral content with background on the MR-visible metabolites. In clinical practice, it is important that relevant MRSI results become available rapidly, reliably and in an easy digestible way. However, this functionality is currently not fully available for prostate MRSI, which is a major obstacle for routine use by inexperienced clinicians. Routine use requires more automation in the processing of raw data than is currently available. Therefore, we pay specific attention in this review on the status and prospects of the automated handling of prostate MRSI data, including quality control. The clinical potential of three-dimensional MRSI of the prostate is illustrated with literature examples on prostate cancer detection, its localisation in the prostate, its role in the assessment of cancer aggressiveness and in the selection and monitoring of therapy.

Efficacy of Withania somnifera on seminal plasma metabolites of infertile males: a proton NMR study at 800 MHz

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Indian systems of medicine use roots of Withania somnifera for impotence, infertility treatment, stress, and the aging process. Although Withania somnifera improves semen quality by regulating reproductive hormone levels and oxidative stress, the molecular mechanism is not clear.

AIM OF THE STUDY

Our study uses high-resolution Nuclear Magnetic Resonance (NMR) spectroscopy to explore the scientific basis to reveal the pre- and post-treatment efficacy of Withania somnifera on seminal plasma of infertile men-which remains unexplored to date.

MATERIALS AND METHODS

A total of 180 infertile male patients were administered Withania somnifera root powder at the rate of 5 g/d for a 3-month period. The study included age-matched, healthy men as a control (n=50) group. Proton NMR spectroscopy was used to measure lactate, alanine, glutamate, glutamine, citrate, lysine, choline, glycerophosphocholine (GPC), glycine, tyrosine, histidine, phenylalanine, and uridine in all seminal plasma samples. To appraise infertility levels, we also measured sperm concentration, motility, lipid peroxide, and hormonal perturbation.

RESULTS

Withania somnifera therapy repairs the disturbed concentrations of lactate, alanine, citrate, GPC, histidine, and phenylalanine in seminal plasma and recovers the quality of semen of post-treated compared to pre-treated infertile men. Serum biochemistry was also improved over post-therapy in infertile men. Our findings reveal that Withania somnifera not only reboots enzymatic activity of metabolic pathways and energy metabolism but also invigorates the harmonic balance of seminal plasma metabolites and reproductive hormones in infertile men.

CONCLUSION

The results suggest that Withania somnifera may be used as an empirical therapy for clinical management and treatment of infertility.

Analysis of citrate in low-volume seminal fluid samples using a time-gated measurement of europium luminescence

This work aims to develop and validate a rapid analytical method that enables the measurement of citrate in seminal fluid samples. Samples were obtained from men who were within 9 weeks of a vasectomy operation. Two age ranges were examined, between 40-43 and 50-53 years old, with nearly 100 samples in each case. No patient clinical history was available for this anonymous study, simulating a random screening cohort. The concentration of citrate in 0.5 μL seminal fluid samples was assessed, using a europium emission luminescence method. This involves the ratiometric analysis of two well-separated europium(III) emission bands. Spectral data were obtained using a time-gated spectrometer whose construction and modification is described. Citrate values were confirmed by independent measurements using a citrate lyase enzymatic assay and by 700 MHz ¹H NMR analysis of the seminal fluid. Citrate concentrations were not statistically different between age groups and averaged 35.0(±14.6) mM for the 40-43 group, and 28.2(±12.7) mM for the 50-53 cohort; in each case a polymodal distribution was observed.

Discriminating cancer from noncancer tissue in the prostate by 3-dimensional proton magnetic resonance spectroscopic imaging: a prospective multicenter validation study

OBJECTIVES

A prospective multicenter validation of the ability of 1H magnetic resonance spectroscopic imaging (MRSI) to distinguish cancer from noncancer tissues throughout the prostate with histopathology of the resected organ as the standard of reference.

MATERIALS AND METHODS

Institutional review board approval was obtained for all centers and all participating patients and volunteers provided written informed consent. Ninety-nine patients and 10 age-matched volunteers from 8 participating centers underwent magnetic resonance imaging and 3-dimensional MRSI with an endorectal coil at 1.5 T. Selected MRSI voxels were assigned to the peripheral zone (PZ), the central gland (CG), the periurethral area, and cancer tissue. Signal ratios of choline + creatine to citrate (CC/C) in spectra of these voxels were automatically calculated. Receiver operating characteristic curves were constructed to assess the accuracy by which this ratio can discriminate cancer from noncancer tissue.

RESULTS

A total of 70% of voxels in noncancer tissue and 90% of voxels in cancer tissue passed the quality check of the automatically fitted spectra. The median CC/C was significantly different between any noncancer and cancer tissue (P < 0.0001), but not between the different contributing centers. CC/C increased with cancer focus size (P =0.0008) and certainty of voxel mapping to histopathologic cancer site (P 0.0001). The area under the receiver operating characteristic curve for discriminating voxels of cancer tissue from noncancer tissue was 0.88 (confidence interval: 0.84-0.92) in the PZ and 0.76 (confidence interval: 0.71- 0.81) in the CG.

Metabolomics: a novel approach to early and noninvasive prostate cancer detection

Prostate cancer (PCa) is the most commonly diagnosed visceral cancer in men and is responsible for the second highest cancer-related male mortality rate in Western countries, with increasing rates being reported in Korea, Japan, and China. Considering the low sensitivity of prostate-specific antigen (PSA) testing, it is widely agreed that reliable, age-independent markers of the presence, nature, and progression of PCa are required to facilitate diagnosis and timely treatment. Metabolomics or metabonomics has recently emerged as a novel method of PCa detection owing to its ability to monitor changes in the metabolic signature, within biofluids or tissue, that reflect changes in phenotype and function. This review outlines the physiology of prostate tissue and prostatic fluid in health and in malignancy in relation to metabolomics as well as the principles underlying the methods of metabolomic quantification. Promising metabolites, metabolic profiles, and their correlation with the presence and stage of PCa are summarized. Application of metabolomics to biofluids and in vivo quantification as well as the direction of current research in supplementing and improving current methods of detection are discussed. The current debate in the urology literature on sarcosine as a potential biomarker for PCa is reviewed and discussed. Metabolomics promises to be a valuable tool in the early detection of PCa that may enable earlier treatment and improved clinical outcomes.

Comparison of qualitative and quantitative approach to prostate MR spectroscopy in peripheral zone cancer detection

OBJECTIVE

To compare the diagnostic performance of a qualitative (pattern recognition) and a quantitative (numerical assessment) approach to magnetic resonance spectroscopy (MRS) in the diagnosis of peripheral zone prostate cancer.

METHODS

185 patients (131 with histopathologically proven cancer, 54 normal/benign after at least 12 months follow-up) were prospectively evaluated with qualitative MRS using a 4-point scale between 3/2004 and 1/2008, and retrospectively reassessed using a prototype quantitative postprocessing software in April 2008. Based on pathology and follow-up data, diagnostic performance parameters were calculated.

RESULTS

The qualitative and quantitative approaches were concordant in 78.9% (146/185) of cases. The difference between the areas under the ROC curve (0.791 versus 0.772, respectively) was not statistically significant. The sensitivity, specificity and accuracy were 55.7%, 94.4% and 67.0% for the qualitative approach, and 55.0%, 83.3% and 63.2% for the quantitative approach. The sensitivity for high grade tumours (Gleason 4+3 or higher) was 85.2% (23/27) for both approaches. All cancers missed on either one approach separately (31/31) and 91% of cancers missed on both approaches together (23/27) were of lower grade (Gleason 3+4 or lower).

CONCLUSIONS

Qualitative and quantitative approaches to MRS yield similar diagnostic results. Discordances in tumour detection only occurred in lower grade cancers.

NMR and MS methods for metabonomics

Metabonomics, also often referred to as "metabolomics" or "metabolic profiling," is the systematic profiling of metabolites in bio-fluids or tissues of organisms and their temporal changes. In the last decade, metabonomics has become increasingly popular in drug development, molecular medicine, and other biotechnology fields, since it profiles directly the phenotype and changes thereof in contrast to other "-omics" technologies. The increasing popularity of metabonomics has been possible only due to the enormous development in the technology and bioinformatics fields. In particular, the analytical technologies supporting metabonomics, i.e., NMR, LC-MS, UPLC-MS, and GC-MS have evolved into sensitive and highly reproducible platforms allowing the determination of hundreds of metabolites in parallel. This chapter describes the best practices of metabonomics as seen today. All important steps of metabolic profiling in drug development and molecular medicine are described in great detail, starting from sample preparation, to determining the measurement details of all analytical platforms, and finally, to discussing the corresponding specific steps of data analysis.

Quantitative (1) H MR spectroscopic imaging of the prostate gland using LCModel and a dedicated basis-set: correlation with histologic findings

Proton magnetic resonance spectroscopic imaging ((1) H-MRSI) has been advocated as a valuable tool for prostate cancer diagnosis. However, a barrier to widespread clinical use of this technique is the lack of robust quantification methods that yield reproducible results in an institution-independent manner. The main goal of this study was to develop a standardized and fully automated approach (LCModel-based) for quantitative prostate (1) H-MRSI. To this end, a dedicated basis set was constructed by the combination of simulated (citrate, Cit; choline, Cho, and creatine, CR) and experimentally acquired (spermine, Spm) spectra. The overlapping Spm, Cho, and Cr could be resolved and quantified individually, thus allowing for the independent assessment of glandular (Cit and Spm) and proliferative (Cho) components. Several metabolite ratios were calculated and compared to the histologic findings of prostatectomy specimens from 10 prostate cancer patients with Gleason scores (3 + 3) and (3 + 4). The Cho mole fraction and the Cho/(Cit + Spm) ratio were found to best discriminate between prostate cancer and healthy tissue. The comparison between the quantitative MRSI results and the histologic findings suggests that no correlation exists between the detected metabolic alterations and the Gleason score of low-grade tumors.

NMR methods for unravelling the spectra of complex mixtures

The main methods for the simplification of the NMR of complex mixtures by selective attenuation/suppression of the signals of certain components are presented. The application of relaxation, diffusion and PSR filters and other techniques to biological samples, pharmaceuticals, foods, living organisms and natural products are illustrated with examples.

Impact of ocean acidification on energy metabolism of oyster, Crassostrea gigas--changes in metabolic pathways and thermal response

Climate change with increasing temperature and ocean acidification (OA) poses risks for marine ecosystems. According to Pörtner and Farrell, synergistic effects of elevated temperature and CO₂-induced OA on energy metabolism will narrow the thermal tolerance window of marine ectothermal animals. To test this hypothesis, we investigated the effect of an acute temperature rise on energy metabolism of the oyster, Crassostrea gigas chronically exposed to elevated CO₂ levels (partial pressure of CO₂ in the seawater ~0.15 kPa, seawater pH ~ 7.7). Within one month of incubation at elevated PCo₂ and 15 °C hemolymph pH fell (pH(e) = 7.1 ± 0.2 (CO₂-group) vs. 7.6 ± 0.1 (control)) and P(e)CO₂ values in hemolymph increased (0.5 ± 0.2 kPa (CO₂-group) vs. 0.2 ± 0.04 kPa (control)). Slightly but significantly elevated bicarbonate concentrations in the hemolymph of CO₂-incubated oysters ([HCO₃⁻](e) = 1.8 ± 0.3 mM (CO₂-group) vs. 1.3 ± 0.1 mM (control)) indicate only minimal regulation of extracellular acid-base status. At the acclimation temperature of 15 °C the OA-induced decrease in pH(e) did not lead to metabolic depression in oysters as standard metabolism rates (SMR) of CO₂-exposed oysters were similar to controls. Upon acute warming SMR rose in both groups, but displayed a stronger increase in the CO₂-incubated group. Investigation in isolated gill cells revealed a similar temperature dependence of respiration between groups. Furthermore, the fraction of cellular energy demand for ion regulation via Na+/K+-ATPase was not affected by chronic hypercapnia or temperature. Metabolic profiling using ¹H-NMR spectroscopy revealed substantial changes in some tissues following OA exposure at 15 °C. In mantle tissue alanine and ATP levels decreased significantly whereas an increase in succinate levels was observed in gill tissue. These findings suggest shifts in metabolic pathways following OA-exposure. Our study confirms that OA affects energy metabolism in oysters and suggests that climate change may affect populations of sessile coastal invertebrates such as mollusks.

The effect of experimental conditions on the detection of spermine in cell extracts and tissues

The aim of this work was to investigate the effect of experimental conditions on the visibility of polyamines. In solution the chemical shift of the three groups of peaks (at approximately 1.8, 2.1 and 3.1 ppm) were found to be pH dependent. Relaxation times in aqueous solution at pH 7.0, 298 K and 11.74 T were measured to be: putrescine (T(1) = 2.49 s, T(2) = 2.07 s), spermidine (T(1) = 1.27 s, T(2) = 1.05 s) and spermine (T(1) = 1.02 s, T(2) = 0.82 s). Simple spin-echo sequences could not be used to measure T(2) as the spins also experience phase evolution from homonuclear coupling which imposes a modulation on the T(2) decay curve. This modulation is eliminated by using CPMG sequences with an echo spacing of <500 micros. Relaxation times for spermine in solution in presence of metal ions and protein showed that metal ions had little effect on T(2); however, addition of 15 mg/ml bovine serum albumin reduced T(2) of spermine (0.41 s at 298 K and 0.19 s at 277 K) but was not as short as the T(2) of the polyamine peak in prostatic tissue (0.03 s at 277 K). The MR visibility of polyamines in prostate cell extracts, PC-3 xenograft (intact as well as extracted) and intact human prostatic tissues were investigated. Polyamines were not detected in methanol/chloroform extracts, but were visible in perchloric acid extracts of prostate tumour cells. No polyamines were detected in the HR MAS spectra of three samples of whole PC-3 xenograft tissue studied. In summary, the chemical shift of polyamine species is pH dependent, while protein binding causes peak broadening and reduction in T(2). Perchloric acid extraction improves visibility of intracellular polyamines, but whole tissue polyamines are not seen in xenografts without epithelial/ ductal structure.

Spectroscopic and statistical methods in metabonomics

Metabonomics is rapidly evolving through advances in analytical technologies together with the development of new hyphenated approaches that are increasingly being applied to analyze complex biological systems. Improvements in analytical performance, such as increased sensitivity and selectivity, are providing greater resolution to analytical datasets and the rich potential of metabonomics as a systems biology tool of choice is becoming clear. However, such improvements are resulting in datasets becoming increasingly demanding in terms of data handling and interpretation, and the degree to which metabonomics continues to develop will be dependent on how chemometrics and data-handling approaches keep pace with continually improving analytical technologies. This review provides an overview of the field of metabonomics, with a particular focus on the analytical techniques that are chiefly employed and the chemometric methods that have found most use. However, in addition, we mention less widely used analytical methods and suggest that advanced statistical methods will play a larger role in the future.

Metabolite profiling of the intraerythrocytic malaria parasite Plasmodium falciparum by (1)H NMR spectroscopy

NMR spectroscopy was used to identify and quantify compounds in extracts prepared from mature trophozoite-stage Plasmodium falciparum parasites isolated by saponin-permeabilisation of the host erythrocyte. One-dimensional (1)H NMR spectroscopy and four two-dimensional NMR techniques were used to identify more than 50 metabolites. The intracellular concentrations of over 40 metabolites were estimated from the (1)H NMR spectra of extracts prepared by four extraction methods: perchloric acid, methanol/water, methanol/chloroform/water, and methanol alone. The metabolites quantified included: the majority of the biological alpha-amino acids; 4-aminobutyric acid; mono-, di- and tri-carboxylic acids; nucleotides; polyamines; myo-inositol; and phosphocholine and phosphoethanolamine. The parasites also contained a significant concentration (up to 12 mM) of the exogenous buffering agent, HEPES. Although the metabolite profiles obtained with each extraction method were broadly similar, perchloric acid was found to have significant advantages over the other extraction media.

Dynamic biochemical information recovery in spontaneous human seminal fluid reactions via 1H NMR kinetic statistical total correlation spectroscopy

Human seminal fluid (HSF) is a complex mixture of reacting glandular metabolite and protein secretions that provides critical support functions in fertilization. We have employed 600-MHz (1)H NMR spectroscopy to compare and contrast the temporal biochemical and biophysical changes in HSF from infertile men with spinal cord injury compared to age-matched controls. We have developed new approaches to data analysis and visualization to facilitate the interpretation of the results, including the first application of the recently published K-STOCSY concept to a biofluid, enhancing the extraction of information on biochemically related metabolites and assignment of resonances from the major seminal protein, semenogelin. Principal components analysis was also applied to evaluate the extent to which macromolecules influence the overall variation in the metabolic data set. The K-STOCSY concept was utilized further to determine the relationships between reaction rates and metabolite levels, revealing that choline, N-acetylglucosamine, and uridine are associated with higher peptidase activity. The novel approach adopted here has the potential to capture dynamic information in any complex mixture of reacting chemicals including other biofluids or cell extracts.

A qualitative approach to combined magnetic resonance imaging and spectroscopy in the diagnosis of prostate cancer

PURPOSE

To investigate the feasibility and diagnostic value of a whole prostate qualitative approach to combined magnetic resonance imaging and spectroscopy (MRI+MRS) in the detection of prostate cancer in patients with elevated PSA.

MATERIALS AND METHODS

Three hundred and fifty six subjects (mean serum PSA 11.47ng/ml, range 0.40-133ng/ml) were examined with fast-T2-weighted images (MRI) and 3D-magnetic resonance spectroscopy (MRS). Both modalities were qualitatively analyzed on a whole prostate basis by a single radiologist using a 4-point diagnostic scale. Prostate cancer was histopathologically proven in 220 patients and non-evidence of cancer was determined after at least 12 months clinical follow-up in 136 subjects.

RESULTS

Receiver operating curve analysis revealed a significantly better diagnostic performance of MRI+MRS (A(z)=0.857) than MRI alone (A(z)=0.801) and MRS alone (A(z)=0.810). The sensitivity, specificity and accuracy of MRI+MRS for detection of prostate cancer were 72.3%, 92.6%, and 80.1%, respectively.

CONCLUSIONS

Spectral evaluation with a whole prostate qualitative approach is feasible in routine clinical practice. The combination of MRI and MRS yields superior diagnostic results than either modality alone.

Seminal Oligouridinosis: Low Uridine Secretion as a Biomarker for Infertility in Spinal Neurotrauma

Background: Compromised sexual health is a major rehabilitative barrier for men with lower–spinal cord injury (SCI). Although studies have revealed decreased sperm motility, the quantitative biochemical changes that underlie the infertility mechanism remain poorly understood.

Methods: We employed a nontargeted approach combining 800 MHz hydrogen nuclear magnetic resonance (1H NMR) spectroscopy and ultra-performance liquid chromatography–mass spectrometry (UPLC-MS) with pattern recognition methods to analyze seminal fluid metabolite profiles in 10 men with and 8 without SCI above thoracic vertebra 10 (T10).

Results: The metabolic phenotype for SCI could be predicted from the 1H NMR data. The median concentration of uridine in fertile controls was 1.55 mmol/L (range 1.0–5.0 mmol/L), but was undetectable by both NMR and MS in all but 2 individuals from the SCI group, one who later fathered a child without assisted fertility techniques.

Conclusions: We hypothesize that uridine is likely to be an essential precursor to metabolites required for capacitation and is a potential marker for the prognosis of post-SCI functional fertility recovery. We derived the term “seminal oligouridinosis” to describe this newly identified condition.