Advances in targeted liquid chromatography-tandem mass spectrometry methods for endocannabinoid and N-acylethanolamine quantification in biological matrices: A systematic review.

Liquid chromatography paired with tandem mass spectrometry (LC-MS/MS) is the gold standard in measurement of endocannabinoid concentrations in biomatrices. We conducted a systematic review of literature to identify advances in targeted LC-MS/MS methods in the period 2017-2024. We found that LC-MS/MS methods for endocannabinoid quantification are relatively consistent both across time and across biomatrices. Recent advances have primarily been in three areas: (1) sample preparation techniques, specific to the chosen biomatrix; (2) the range of biomatrices tested, recently favoring blood matrices; and (3) the breadth of endocannabinoid and endocannabinoid-like analytes incorporated into assays. This review provides a summary of the recent literature and a guide for researchers looking to establish the best methods for quantifying endocannabinoids in a range of biomatrices.

Food-derived extracellular vesicles in the human gastrointestinal tract: Opportunities for personalised nutrition and targeted therapeutics.

Food-derived extracellular vesicles (FDEVs) such as those found in mammalian milk and plants are of great interest for both their health benefits and ability to act as biological nanocarriers. While the extracellular vesicle (EV) field is expanding rapidly to perform characterisation studies on FDEVs from plants, yeasts and bacteria, species-specific differences in EV uptake and function in the human gastrointestinal (GI) tract are poorly understood. Moreover, the effects of food processing on the EV surfaceome and intraluminal content also raises questions surrounding biological viability once consumed. Here, I present a case for increasing community-wide focus on understanding the cellular uptake of FDEVs from different animal, plant, yeast, and bacterial species and how this may impact their function in the human, which will have implications for human health and therapeutic strategies alike.

Playing pin-the-tail-on-the-protein in extracellular vesicle (EV) proteomics.

Extracellular vesicles (EVs) are anucleate particles enclosed by a lipid bilayer that are released from cells via exocytosis or direct budding from the plasma membrane. They contain an array of important molecular cargo such as proteins, nucleic acids, and lipids, and can transfer these cargoes to recipient cells as a means of intercellular communication. One of the overarching paradigms in the field of EV research is that EV cargo should reflect the biological state of the cell of origin. The true relationship or extent of this correlation is confounded by many factors, including the numerous ways one can isolate or enrich EVs, overlap in the biophysical properties of different classes of EVs, and analytical limitations. This presents a challenge to research aimed at detecting low-abundant EV-encapsulated nucleic acids or proteins in biofluids for biomarker research and underpins technical obstacles in the confident assessment of the proteomic landscape of EVs that may be affected by sample-type specific or disease-associated proteoforms. Improving our understanding of EV biogenesis, cargo loading, and developments in top-down proteomics may guide us towards advanced approaches for selective EV and molecular cargo enrichment, which could aid EV diagnostics and therapeutics research.

A test of pre-exposure spacing and multiple context pre-exposure on the mechanisms of latent inhibition of dental fear: A study protocol.

BACKGROUND: Latent inhibition occurs when exposure to a stimulus prior its direct associative conditioning impairs learning. Results from naturalistic studies suggest that latent inhibition disrupts the learning of dental fear from aversive associative conditioning and thereby reduces the development of dental phobia. Although theory suggests latent inhibition occurs because pre-exposure changes the expected relevance and attention directed to the pre-exposed stimulus, evidence supporting these mechanisms in humans is limited. The aim of this study is to determine if two variables, pre-exposure session spacing and multiple context pre-exposure, potentiate the hypothesized mechanisms of expected relevance and attention and, in turn, increase latent inhibition of dental fear. METHODS: In a virtual reality simulation, child and adult community members (ages 6 to 35) will take part in pre-exposure and conditioning trials, followed by short- and long-term tests of learning. A 100ms puff of 60 psi air to a maxillary anterior tooth will serve as the unconditioned stimulus. Pre-exposure session spacing (no spacing vs. sessions spaced) and multiple context pre-exposure (single context vs. multiple contexts) will be between-subject factors. Stimulus type (pre-exposed to-be conditioned stimulus, a non-pre-exposed conditioned stimulus, and an unpaired control stimulus) and trial will serve as within-subject factors. Baseline pain sensitivity will also be measured as a potential moderator. DISCUSSION: It is hypothesized that spaced pre-exposure and pre-exposure in multiple contexts will increase the engagement of the mechanisms of expected relevance and attention and increase the latent inhibition of dental fear. It is expected that the findings will add to theory on fear learning and provide information to aid the design of future interventions that leverage latent inhibition to reduce dental phobia.

A study protocol testing pre-exposure dose and compound pre-exposure on the mechanisms of latent inhibition of dental fear.

BACKGROUND: Dental stimuli can evoke fear after being paired - or conditioned - with aversive outcomes (e.g., pain). Pre-exposing the stimuli before conditioning can impair dental fear learning via a phenomenon known as latent inhibition. Theory suggests changes in expected relevance and attention are two mechanisms responsible for latent inhibition. In the proposed research, we test whether pre-exposure dose and degree of pre-exposure novelty potentiate changes in expected relevance and attention to a pre-exposed stimulus. We also assess if the manipulations alter latent inhibition and explore the possible moderating role of individual differences in pain sensitivity. METHODS: Participants will be healthy individuals across a wide range of ages (6 to 35 years), from two study sites. Participants will undergo pre-exposure and conditioning followed by both a short-term and long-term test of learning, all in a novel virtual reality environment. The unconditioned stimulus will be a brief pressurized puff of air to a maxillary anterior tooth. Pre-exposure dose (low vs. high) and pre-exposure novelty (element stimulus vs. compound stimuli) will be between-subject factors, with stimulus type (pre-exposed to-be conditioned stimulus, a non-pre-exposed conditioned stimulus, and an unpaired control stimulus) and trial as within-subject factors. Pain sensitivity will be measured through self-report and a cold pressor test. It is hypothesized that a larger dose of pre-exposure and compound pre-exposure will potentiate the engagement of the target mechanisms and thereby result in greater latent inhibition in the form of reduced fear learning. Further, it is hypothesized that larger effects will be observed in participants with greater baseline pain sensitivity. DISCUSSION: The proposed study will test whether pre-exposure dose and compound stimulus presentation change expected relevance and attention to the pre-exposed stimulus, and thereby enhance latent inhibition of dental fear. If found, the results will add to our theoretical understanding of the latent inhibition of dental fear and inform future interventions for dental phobia prevention.

Sex-dimorphism in human serum endocannabinoid and n-acyl ethanolamine concentrations across the lifespan.

The endocannabinoid (ECB) system has recently been considered a potential treatment target for various clinical disorders. However, research around age- and sex-related changes within the ECB system is relatively limited. To improve our understanding of these changes, the current study measured arachidonoyl ethanolamide (AEA), 2-arachidonoyl glycerol (2-AG), oleoylethanolamine (OEA), palmitoylethanolamine (PEA), arachidonic acid (AA), cortisol, and progesterone in pooled serum samples stratified by sex (male and female) and age groups (5-15; 15-30; 30-45; 45-60; 60-75; 85+), using liquid-chromatography tandem mass spectrometry. Serum progesterone levels significantly increased in females of the 15-30 and 30-45 age groups, before declining. Significantly higher cortisol, AEA, 2-AG, OEA, and PEA were found in males and in older age, while significantly higher AA was found in females. Our results indicate that ECBs and related hormones exhibit sexual dimorphism in the age ranges that correspond with female pregnancy, menopause, and post menopause. Male testosterone levels most likely influences male ECB changes throughout the lifespan. Future research could capitalise on these findings by performing repeated measurements in individuals in a longitudinal style, to further refine the temporal profile of age-specific changes to the ECB system identified here.

SWATH-MS Analysis of Blood Plasma and Circulating Small Extracellular Vesicles Enables Detection of Putative Protein Biomarkers of Fertility in Young and Aged Dairy Cows.

The development of biomarkers of fertility could provide benefits for the genetic improvement of dairy cows. Circulating small extracellular vesicles (sEVs) show promise as diagnostic or prognostic markers since their cargo reflects the metabolic state of the cell of origin; thus, they mirror the physiological status of the host. Here, we employed data-independent acquisition mass spectrometry to survey the plasma and plasma sEV proteomes of two different cohorts of Young (Peripubertal; n = 30) and Aged (Primiparous; n = 20) dairy cows (Bos taurus) of high- and low-genetic merit of fertility and known pregnancy outcomes (ProteomeXchange data set identifier PXD042891). We established predictive models of fertility status with an area under the curve of 0.97 (sEV; p value = 3.302e-07) and 0.95 (plasma; p value = 6.405e-08). Biomarker candidates unique to high-fertility Young cattle had a sensitivity of 0.77 and specificity of 0.67 (*p = 0.0287). Low-fertility biomarker candidates uniquely identified in sEVs from Young and Aged cattle had a sensitivity and specificity of 0.69 and 1.0, respectively (***p = 0.0005). Our bioinformatics pipeline enabled quantification of plasma and circulating sEV proteins associated with fertility phenotype. Further investigations are warranted to validate this research in a larger population, which may lead to improved classification of fertility status in cattle.

How I want technology used in my care: Learning from documented choices of people living with dementia using a dyadic decision making tool.

While technologies for aging in place are promoted to support care partners and people living with dementia, perspectives of people living with dementia are underrepresented in both use decisions among families and discussions within academia and industry. This mixed-methods study examined the use preferences of twenty-nine people living with mild Alzheimer's disease (AD) for four categories of technologies: location tracking, in-home sensors, web-cameras, and virtual companion robots. Participants completed a novel dyadic intervention, Let's Talk Tech, where they documented their preferences of the four technology categories for care planning purposes. Post-test interviews were thematically analyzed and provide insight into selection processes. Technology preferences varied considerably by and within participant living with mild AD. Excepting location tracking, non-technology and low-technology options were more desirable than the featured technologies. Control over technology use was of great importance to people living with AD. Considerations given to technology preference selection imperfectly fit within the new Health Technology Acceptance Model (H-TAM) developed for older adults. These findings underscore the importance of including people living with dementia in decision making about technologies to support care at home and the need for further personalization and tailorable technological devices to accommodate and align with their preferences.

Omics Analysis of Extracellular Vesicles Recovered from Infant Formula Products and Milk: Towards Personalized Infant Nutrition.

SCOPE: Milk and milk products such as infant formula (IF) play a fundamental role in serving the nutritional needs of the developing infant. Extracellular vesicles (EVs) in human (HM) and cow milk (CM) contain molecular cargo such as proteins and micro(mi)RNAs that serve as functional messengers between cells and may be of importance to infant health. Most IF is derived from a CM protein base, however differences between HM and CM EV molecular cargo have not been extensively studied. METHODS AND RESULTS: This study develops a pipeline using advanced proteomics and transcriptomics to enable cross-species comparison of milk and IF EVs. The number of nanoparticles per mL of IF is significantly reduced compared to unprocessed CM. 130 proteins and 514 miRNAs are differentially abundant between HM and CM EVs. While 90% of CM EV miRNAs are also identified in IF EVs, only 20% of CM EV proteins are identified in IF EVs. CONCLUSIONS: This workflow identifies key species-specific differences that can be used to optimize IF recipes and enhance infant nutrition. Improved preservation of EV functional molecular cargo in IF products is of critical importance to retaining molecular drivers of good health and should be the focus of future investigations.

Preliminary Efficacy of Let's Talk Tech: Technology Use Planning for Dementia Care Dyads.

Background and Objective: Care partners of people living with dementia require support to knowledgeably navigate decision making about how and when to use monitoring technologies for care purposes. We conducted a pilot study of a novel self-administered intervention, "Let's Talk Tech," for people living with mild dementia and their care partners. This paper presents preliminary efficacy findings of this intervention designed to educate and facilitate dyadic communication about a range of technologies used in dementia care and to document the preferences of the person living with dementia. It is the first-of-its-kind decision-making and planning tool with a specific focus on technology use. Research Design and Methods: We used a 1-group pretest-post-test design and paired t tests to assess change over 2 time periods in measures of technology comprehension, care partner knowledge of the participant living with mild Alzheimer's disease's (AD) preferences, care partner preparedness to make decisions about technology use, and mutual understanding. Thematic analysis was conducted on postintervention interview transcripts to elucidate mechanisms and experiences with Let's Talk Tech. Results: Twenty-nine mild AD dementia care dyads who live together completed the study. There was statistically significant improvement with medium and large effect sizes on outcome measures of care partners' understanding of each technology, care partners' perceptions of the person living with dementia's understanding of each technology, knowledge of the person living with dementia's preferences, decision-making preparedness, and care partners' feelings of mutual understanding. Participants reported that it helped them have important and meaningful conversations about using technology. Discussion and Implications: Let's Talk Tech demonstrated promising preliminary efficacy on targeted measures that can lead to informed, shared decision making about technologies used in dementia care. Future studies should assess efficacy with larger samples and more diverse sample populations in terms of race, ethnicity, and dementia type.

Dynamics of inflammatory cytokine expression in bovine endometrial cells exposed to cow blood plasma small extracellular vesicles (sEV) may reflect high fertility.

Aberrant inflammation in the endometrium impairs reproduction and leads to poor fertility. Small extracellular vesicles (sEV) are nanoparticles 30-200 nm in-size and contain transferable bioactive molecules that reflect the parent cell. Holstein-Friesian dairy cows with divergent genetic merit, high- (n = 10) and low-fertile (n = 10), were identified based on fertility breeding value (FBV), cow ovulation synchronization and postpartum anovulatory intervals (PPAI). In this study, we evaluated the effects of sEVs enriched from plasma of high-fertile (HF-EXO) and low-fertile (LF-EXO) dairy cows on inflammatory mediator expression by bovine endometrial epithelial (bEEL) and stromal (bCSC) cells. Exposure to HF-EXO in bCSC and bEEL cells yielded lower expression of PTGS1 and PTGS2 compared to the control. In bCSC cells exposed to HF-EXO, pro-inflammatory cytokine IL1-α was downregulated compared to the untreated control, IL-12α and IL-8 were downregulated compared to the LF-EXO treatment. Our findings demonstrate that sEVs interact with both endometrial epithelial and stromal cells to initiate differential gene expression, specifically genes relate to inflammation. Therefore, even subtle changes on the inflammatory gene cascade in the endometrium via sEV may affect reproductive performance and/or outcomes. Further, sEV from high-fertile animals acts in a unique direction to deactivate prostaglandin synthases in both bCSC and bEEL cells and deactivate pro-inflammatory cytokines in the endometrial stroma. The results suggest that circulating sEV may serve as a potential biomarker of fertility.

"It Goes Hand in Hand with Us Trying to Get More Kids to Play" Stakeholder Experiences in a Sport and Active Recreation Voucher Program.

Vouchers that reduce the cost of sport and active recreation participation have been shown to increase children's and adolescent's physical activity levels. Yet, the influence of government-led voucher programs on the capacity of sport and active recreation organisations is unclear. This qualitative study explored the experiences of stakeholders in the sport and recreation sector that were engaged in implementing the New South Wales (NSW) Government's Active Kids voucher program in Australia. Semi-structured interviews were conducted with 29 sport and active recreation providers. Interview transcriptions were analysed by a multidisciplinary team using the Framework method. Overall, participants reported that the Active Kids voucher program was an acceptable intervention to address the cost barrier to participation for children and adolescents. Three main steps influenced the capacity of organisations to deliver their sport and recreation programs and the voucher program: (1) Implementation priming-alignment of the intervention aims with stakeholder priorities and early information sharing, (2) Administrative ease-enhanced technology use and establishment of simple procedures, and (3) Innovation impacts-enablement of staff and volunteers to address barriers to participation for their participants. Future voucher programs should include strategies to enhance the capacity of sport and active recreation organisations to meet program guidelines and increase innovation.

The Role of Trust in Older Adult Service Provision at the Onset of the COVID-19 Pandemic.

The COVID-19 pandemic caused near immediate service delivery adaptation among social service and healthcare sectors. Findings from in-depth interviews with 45 senior leaders of social services and healthcare organizations serving older adults in Washington State elucidate the role of trust in service provision at the onset of the pandemic. First, a history of trust facilitated service adaptation. Intentional outreach, programs, and culturally responsive services sustained trust with service recipients. Providing services and information in an older adult's preferred language built trust. Community networks facilitated and reflected trust between organizations and older adults. Finally, mistrust was prevalent for clients who perceived a high risk of experiencing negative consequences from accessing services. Our findings support the need for culturally and linguistically diverse services. To improve trust, the aging network should strengthen and expand partnerships with community-based organizations who have established trust through history, intentionality, and relevance to their service populations..

Study protocol of an investigation of attention and prediction error as mechanisms of action for latent inhibition of dental fear in humans.

BACKGROUND: Evidence suggests that dental anxiety and phobia are frequently the result of direct associative fear conditioning but that pre-exposure to dental stimuli prior to conditioning results in latent inhibition of fear learning. The mechanisms underlying the pre-exposure effect in humans, however, are poorly understood. Moreover, pain sensitivity has been linked to dental fear conditioning in correlational investigations and theory suggests it may moderate the latent inhibition effect, but this hypothesis has not been directly tested. These gaps in our understanding are a barrier to the development of evidence-based dental phobia prevention efforts. METHODS: Healthy volunteers between the ages of 6 and 35 years will be enrolled across two sites. Participants will complete a conditioning task in a novel virtual reality environment, allowing for control over pre-exposure and the examination of behaviour. A dental startle (a brief, pressurized puff of air to a tooth) will serve as the unconditioned stimulus. Using a within-subjects experimental design, participants will experience a pre-exposed to-be conditioned stimulus, a non-pre-exposed to-be conditioned stimulus, and a neutral control stimulus. Two hypothesized mechanisms, changes in prediction errors and attention, are expected to mediate the association between stimulus condition and fear acquisition, recall, and retention. To ascertain the involvement of pain sensitivity, this construct will be measured through self-report and the cold pressor task. DISCUSSION: Dental phobia negatively affects the dental health and overall health of individuals. This study aims to determine the mechanisms through which pre-exposure retards conditioned dental fear acquisition, recall, and retention. A randomized control trial will be used to identify these mechanisms so that they can be precisely targeted and maximally engaged in preventative efforts.

Repairing small type I hiatal hernias at the time of RYGB is not necessary to achieve resolution of reflux symptoms.

INTRODUCTION: Roux-en-Y gastric bypass (RYGB) is the gold standard operation for gastroesophageal reflux disease (GERD) in patients with severe obesity, but there is variability in surgeon opinion regarding whether small type I hiatal hernias (HH) require routine repair concurrently with RYGB. We sought to examine whether leaving small type I HHs unrepaired during RYGB affected GERD outcomes. METHODS: Pre-operatively our patients all receive endoscopy, and select patients with reflux symptoms receive esophagram based on attending surgeon practice and preference. We routinely repair paraesophageal hernias (PEH) concurrently with RYGB, but refrain from repairing small type I HH if, intra-operatively, the gastric fat pad and cardia are below the diaphragm with no evidence of retraction into the mediastinum. Records from 268 consecutive patients undergoing primary RYGB between January 2016 and February 2021 who completed pre-operative GERD-HRQL assessments were reviewed for presence of type I HH or PEH. Mann-Whitney U tests examined the pre-operative to post-operative change in GERD-HRQL in patients with type I HH left unrepaired at the time of RYGB (HH group) and patients with no hernia (NH group). RESULTS: Pre-operatively, GERD-HRQL scores were not statistically different between HH group (median = 7, mean = 8.5, n = 100) and NH group (median = 6.5, mean = 7.2, n = 141) (p > 0.05). Post-operatively, there was no increase in GERD-HRQL scores patients whose hernias were left unrepaired. Neither group had clinically pathologic post-operative GERD-HRQL scores, with median 6 months scores of 1 for HH group (n = 68) versus 1.5 for NH group (n = 90) (p > 0.05), and median 12 months scores of 1.5 for HH group (n = 40) versus 1 for NH group (n = 56) (p > 0.05). CONCLUSION: Repair of small type I HH is not necessary to achieve effective, durable resolution of reflux symptoms with RYGB. Omitting repair reduces operative time, cost, and potential risk without adverse impact on post-operative reflux symptoms.

Advance Planning for Technology Use in Dementia Care: Development, Design, and Feasibility of a Novel Self-administered Decision-Making Tool.

BACKGROUND: Monitoring technologies are used to collect a range of information, such as one's location out of the home or movement within the home, and transmit that information to caregivers to support aging in place. Their surveilling nature, however, poses ethical dilemmas and can be experienced as intrusive to people living with Alzheimer disease (AD) and AD-related dementias. These challenges are compounded when older adults are not engaged in decision-making about how they are monitored. Dissemination of these technologies is outpacing our understanding of how to communicate their functions, risks, and benefits to families and older adults. To date, there are no tools to help families understand the functions of monitoring technologies or guide them in balancing their perceived need for ongoing surveillance and the older adult's dignity and wishes. OBJECTIVE: We designed, developed, and piloted a communication and education tool in the form of a web application called Let's Talk Tech to support family decision-making about diverse technologies used in dementia home care. The knowledge base about how to design online interventions for people living with mild dementia is still in development, and dyadic interventions used in dementia care remain rare. We describe the intervention's motivation and development process, and the feasibility of using this self-administered web application intervention in a pilot sample of people living with mild AD and their family care partners. METHODS: We surveyed 29 mild AD dementia care dyads living together before and after they completed the web application intervention and interviewed each dyad about their experiences with it. We report postintervention measures of feasibility (recruitment, enrollment, and retention) and acceptability (satisfaction, quality, and usability). Descriptive statistics were calculated for survey items, and thematic analysis was used with interview transcripts to illuminate participants' experiences and recommendations to improve the intervention. RESULTS: The study enrolled 33 people living with AD and their care partners, and 29 (88%) dyads completed the study (all but one were spousal dyads). Participants were asked to complete 4 technology modules, and all completed them. The majority of participants rated the tool as having the right length (>90%), having the right amount of information (>84%), being very clearly worded (>74%), and presenting information in a balanced way (>90%). Most felt the tool was easy to use and helpful, and would likely recommend it to others. CONCLUSIONS: This study demonstrated that our intervention to educate and facilitate conversation and documentation of preferences is preliminarily feasible and acceptable to mild AD care dyads. Effectively involving older adults in these decisions and informing care partners of their preferences could enable families to avoid conflicts or risks associated with uninformed or disempowered use and to personalize use so both members of the dyad can experience benefits.

A Comparison of Blood Plasma Small Extracellular Vesicle Enrichment Strategies for Proteomic Analysis.

Proteomic analysis of small extracellular vesicles (sEVs) poses a significant challenge. A 'gold-standard' method for plasma sEV enrichment for downstream proteomic analysis is yet to be established. Methods were evaluated for their capacity to successfully isolate and enrich sEVs from plasma, minimise the presence of highly abundant plasma proteins, and result in the optimum representation of sEV proteins by liquid chromatography tandem mass spectrometry. Plasma from four cattle (Bos taurus) of similar physical attributes and genetics were used. Three methods of sEV enrichment were utilised: ultracentrifugation (UC), size-exclusion chromatography (SEC), and ultrafiltration (UF). These methods were combined to create four groups for methodological evaluation: UC + SEC, UC + SEC + UF, SEC + UC and SEC + UF. The UC + SEC method yielded the highest number of protein identifications (IDs). The SEC + UC method reduced plasma protein IDs compared to the other methods, but also resulted in the lowest number of protein IDs overall. The UC + SEC + UF method decreased sEV protein ID, particle number, mean and mode particle size, particle yield, and did not improve purity compared to the UC + SEC method. In this study, the UC + SEC method was the best method for sEV protein ID, purity, and overall particle yield. Our data suggest that the method and sequence of sEV enrichment strategy impacts protein ID, which may influence the outcome of biomarker discovery studies.

Pathways to program entry: Factors promoting entry and participation in veteran peer-support programs.

Given the documented underutilization of community-based services by veterans, this study aims to identify factors promoting engagement in programs. Qualitative data from interviews with 154 veterans in peer support programs were analyzed to identify factors promoting program entry and participation. Findings confirm the importance of both internal and external factors for program engagement. Internal factors included feeling a sense of disconnection, dissatisfaction with other programs, emotional needs, concrete needs, and a desire to serve others. External factors included encouragement from others, program culture, and program climate. Implications for program development and evaluation are discussed. While much of the current literature on veterans focuses on individual characteristics promoting or impeding service use, this study provides insight into programmatic features such as culture and climate which foster participation and meaningful engagement. Ultimately, programs serving veterans need input and influence by veterans, and should emphasize peer support and other opportunities for social connection.

Proteomic profiling of plasma-derived small extracellular vesicles: a novel tool for understanding the systemic effects of tick burden in cattle.

Cattle ticks pose a significant threat to the health and profitability of cattle herds globally. The investigation of factors leading to natural tick resistance in cattle is directed toward targeted breeding strategies that may combat cattle tick infestation on the genetic level. Exosomes (EXs), small extracellular vesicles (EVs) of 50 to 150 nm diameter, are released from all cell types into biofluids such as blood plasma and milk, have been successfully used in diagnostic and prognostic studies in humans, and can provide essential information regarding the overall health state of animals. Mass spectrometry (MS) is a highly sensitive proteomics application that can be used to identify proteins in a complex mixture and is particularly useful for biomarker development. In this proof of principle study, EXs were isolated from the blood plasma of cattle (Bos taurus) with high (HTR) and low tick resistance (LTR) (n = 3/group). Cattle were classified as HTR or LTR using a tick scoring system, and EXs isolated from the cattle blood plasma using an established protocol. EXs were subjected to MS analysis in data-dependent acquisition mode and protein search performed using Protein Pilot against the B. taurus proteome. A total of 490 unique proteins were identified across all samples. Of these, proteins present in all replicates from each group were selected for further analysis (HTR = 121; LTR = 130). Gene ontology analysis was performed using PANTHER GO online software tool. Proteins unique to HTR and LTR cattle were divided by protein class, of which 50% were associated with immunity/defense in the HTR group, whereas this protein class was not detected in EXs from LTR cattle. Similarly, unique proteins in HTR cattle were associated with B-cell activation, immunoglobins, immune response, and cellular iron ion homeostasis. In LTR cattle, unique exosomal proteins were associated with actin filament binding, purine nucleotide binding, plasma membrane protein complex, and carbohydrate derivative binding. This is the first study to demonstrate that MS analysis of EXs derived from the blood plasma of HTR and LTR cattle can be successfully applied to profile the systemic effects of tick burden.

Cattle ticks are a significant burden to cattle industries globally. Current methods to treat cattle ticks are costly and inefficient in the long term. It has been noted that while some cattle may exhibit a natural resistance to ticks, others carry a heavy tick burden. The study of small extracellular vesicles, or exosomes (EXs), isolated from cattle blood plasma provides a noninvasive way of analyzing changes at the cellular level and may be of use in understanding the systemic effects of tick burden or factors leading to natural resistance. The aim of this study was to assess high (HTR) and low tick resistance (LTR) cattle identified using a tick burden scoring system by analyzing the protein content of circulating EXs via qualitative proteomics analysis. We found that a class of proteins related to defense/immunity comprised 50% of proteins unique to HTR cattle, while this protein class was not detected in proteins unique to LTR cattle. Additionally, epidermal growth factor­calcium-binding protein domains were 2-fold increased in LTR cattle compared with HTR cattle, indicating a possible mechanism for widespread metabolic change. This is the first study to employ proteomic analysis of exosomal cargo as an approach to understanding the systemic effects of tick burden in cattle.

Exosomal Cargo May Hold the Key to Improving Reproductive Outcomes in Dairy Cows.

The reproductive status of dairy cows remains a challenge for dairy farmers worldwide, with impaired fertility linked to a significant reduction in herd profitability, due in part to impaired immunity, increased metabolic pressure, and longer postpartum anestrous interval (PPAI). Exosomes are nanovesicles released from a variety of cell types and end up in circulation, and carry proteins, bioactive peptides, lipids, and nucleic acids specific to the place of origin. As such, their role in health and disease has been investigated in humans and animals. This review discusses research into exosomes in the context of reproduction in dairy herds and introduces recent advances in mass-spectrometry (MS) based proteomics that have a potential to advance quantitative profiling of exosomal protein cargo in a search for early biomarkers of cattle fertility.