Postnatal hyperglycemia alters amino acid profile in retinas (model of Phase I ROP)

Nutritional deprivation occurring in most preterm infants postnatally can induce hyperglycemia, a significant and independent risk factor for suppressing physiological retinal vascularization (Phase I retinopathy of prematurity (ROP)), leading to compensatory but pathological neovascularization. Amino acid supplementation reduces retinal neovascularization in mice. Little is known about amino acid contribution to Phase I ROP. In mice modeling hyperglycemia-associated Phase I ROP, we found significant changes in retinal amino acids (including most decreased L-leucine, L-isoleucine, and L-valine). Parenteral L-isoleucine suppressed physiological retinal vascularization. In premature infants, severe ROP was associated with a higher mean intake of parenteral versus enteral amino acids in the first two weeks of life after adjustment for treatment group, gestational age at birth, birth weight, and sex. The number of days with parenteral amino acids support independently predicted severe ROP. Further understanding and modulating amino acids may help improve nutritional intervention and prevent Phase I ROP.

Do the retinal abnormalities in X-linked juvenile retinoschisis include impaired phototransduction?

X-linked juvenile retinoschisis (XLRS), a hereditary retinal disorder primarily affecting males, is characterized by the formation of cystic spaces between the outer plexiform layer and outer nuclear layer of the retina. Mutations in the RS1 gene, which encodes the extracellular binding protein retinoschisin, are responsible for XLRS pathogenesis. While the role of retinoschisin in maintaining retinal integrity is well established, there is growing evidence suggesting compromised photoreceptor function in XLRS. To investigate the molecular pathways affected by RS1 deficiency, particularly in phototransduction, we performed electroretinographic (ERG) and proteomic analyses on retinae from Rs1 knockout mice, a model of human XLRS. The Rs1 knockout mice had reduced ERG a-wave amplitudes. Correspondingly, differential expression analysis revealed downregulation of proteins crucial for phototransduction, with Ingenuity Pathway Analysis (IPA) highlighting "phototransduction" as the most significantly downregulated biological theme. Compensatory mechanisms were also observed in the IPA, including upregulation of synaptic remodeling, inflammation, cell adhesion, and G-protein signaling. These findings strongly implicate an underrecognized role of photoreceptor dysfunction in XLRS pathology. We speculate that entrapment of mutant retinoschisin protein within photoreceptor inner segments as well as disrupted reciprocal regulation between L-type voltage-gated calcium channels and retinoschisin contribute to the dysfunction in photoreceptors.

FGF21 via mitochondrial lipid oxidation promotes physiological vascularization in a mouse model of Phase I ROP

Hyperglycemia in early postnatal life of preterm infants with incompletely vascularized retinas is associated with increased risk of potentially blinding neovascular retinopathy of prematurity (ROP). Neovascular ROP (Phase II ROP) is a compensatory but ultimately pathological response to the suppression of physiological postnatal retinal vascular development (Phase I ROP). Hyperglycemia in neonatal mice which suppresses physiological retinal vascular growth is associated with decreased expression of systemic and retinal fibroblast growth factor 21 (FGF21). FGF21 administration promoted and FGF21 deficiency suppressed the physiological retinal vessel growth. FGF21 increased serum adiponectin (APN) levels and loss of APN abolished FGF21 promotion of physiological retinal vascular development. Blocking mitochondrial fatty acid oxidation also abolished FGF21 protection against delayed physiological retinal vessel growth. Clinically, preterm infants developing severe neovascular ROP (versus non-severe ROP) had a lower total lipid intake with more parenteral and less enteral during the first 4 weeks of life. Our data suggest that increasing FGF21 levels in the presence of adequate enteral lipids may help prevent Phase I retinopathy (and therefore prevent neovascular disease).

Abstract WMP18: Protection Against Dementia In Mouse VCID By Repetitive Hypoxic Conditioning: Cortical Proteomics Defines Disease And Disease Resilient Phenotypes

Introduction: Vascular cognitive impairment and dementia (VCID) exerts huge morbidity costs, and efficacious therapies are lacking. In a well-established mouse model of VCID, we recently documented in vivo an epigenetically-induced resilience to reference memory deficits by 2 mo of repetitive hypoxic conditioning (RHC) treatment prior to bilateral carotid artery stenosis-induced chronic cerebral hypoperfusion (CCH). The present study was undertaken to define the phenotypic basis of this cognition-protective effect.

Methods: Samples of prefrontal cortex from untreated and RHC-treated mice were obtained after 4 mo of CCH, along with samples from age-matched sham-CCH controls, and analyzed by mass spectrometry using TMTpro labels for quantification. Differentially expressed proteins were bioinformatically analyzed using IPA (Qiagen), with rigid thresholds/filters for fold-change, z-scores, and statistical significance applied.

Results: 5071 proteins were identified - 3975 of which were quantified - in the 3 experimental groups. Relative to the cortical proteome of controls, the cortex of memory-impaired CCH mice exhibited a downregulation of proteins involved in Nrf2 signaling and synaptogenesis signaling pathways, and an increase of proteins and related proinflammatory mediators participating in leukocyte extravasation signaling. In addition, gamma secretase levels were increased. Treatment with RHC prior to CCH abrogated the aforementioned Nrf2, synaptogenesis, and leukocyte signaling changes, increased proteins driving oxidative phosphorylation, Rho-mediated CXCR4 signaling, DNA repair, and diverse cell survival networks, and reduced protein enrichments in both apoptosis and necrosis signaling, and reactive oxygen species generating, pathways. Levels of both amyloid precursor protein and amyloid-beta levels, as well as tau, were also lower in RHC-treated, dementia-resilient mice.

Conclusions: These novel findings reveal potential mechanistic insights into relatively early changes in phenotype that characterize VCID and, in turn, how this phenotype is modified by an efficacious epigenetic therapeutic. Causal studies designed to confirm these multifactorial mechanisms of cognitive protection are warranted.

Global Sex Disparity of COVID-19: A Descriptive Review of Sex Hormones and Consideration for the Potential Therapeutic Use of Hormone Replacement Therapy in Older Adults

The 2019-2020 SARS-related coronavirus-2 (SARS-CoV-2) pandemic has brought unprecedented challenges to healthcare sectors around the world. As of November 2020, there have been over 64 million confirmed cases and approaching 2 million deaths globally. Despite the large number of positive cases, there are very limited established standards of care and therapeutic options available. To date, there is still no Food and Drug Administration (FDA) approved vaccine for COVID-19, although there are several options in various clinical trial stages. Herein, we have performed a global review evaluating the roles of age and sex on COVID-19 hospitalizations, ICU admissions, deaths in hospitals, and deaths in nursing homes. We have identified a trend in which elderly and male patients are significantly affected by adverse outcomes. There is evidence suggesting that sex hormone levels can influence immune system function against SARS-CoV-2 infection, thus reducing the adverse effects of COVID-19. Since older adults have lower levels of these sex hormones, we therefore speculate, within rational scientific context, that sex steroids, such as estrogen and progesterone, needs further consideration for use as alternative therapeutic option for treating COVID-19 elderly patients. To our knowledge, this is the first comprehensive article evaluating the significance of sex hormones in COVID-19 outcomes in older adults.

Sexual differences in mitochondrial and related proteins in rat cerebral microvessels: A proteomic approach

Sex differences in mitochondrial numbers and function are present in large cerebral arteries, but it is unclear whether these differences extend to the microcirculation. We performed an assessment of mitochondria-related proteins in cerebral microvessels (MVs) isolated from young, male and female, Sprague-Dawley rats. MVs composed of arterioles, capillaries, and venules were isolated from the cerebrum and used to perform a 3 versus 3 quantitative, multiplexed proteomics experiment utilizing tandem mass tags (TMT), coupled with liquid chromatography/mass spectrometry (LC/MS). MS data and bioinformatic analyses were performed using Proteome Discoverer version 2.2 and Ingenuity Pathway Analysis. We identified a total of 1969 proteins, of which 1871 were quantified by TMT labels. Sixty-four proteins were expressed significantly (p < 0.05) higher in female samples compared with male samples. Females expressed more mitochondrial proteins involved in energy production, mitochondrial membrane structure, anti-oxidant enzyme proteins, and those involved in fatty acid oxidation. Conversely, males had higher expression levels of mitochondria-destructive proteins. Our findings reveal, for the first time, the full extent of sexual dimorphism in the mitochondrial metabolic protein profiles of MVs, which may contribute to sex-dependent cerebrovascular and neurological pathologies.

Differential regulation of cerebral microvascular transcription by single and repetitive hypoxic conditioning

Systemic conditioning therapeutics afford brain protection at all levels of organization, occurring autonomously for neurons, glia, vascular smooth muscle, and endothelium, which are mediated systemically for the adaptive and innate immune system. The present study was undertaken to examine acute (3 h) and delayed (2 days) gene expression changes in mouse cerebral microvessels following single hypoxic conditioning (HX1) and repetitive hypoxic conditioning (HX9), the latter for which we showed previously to extend focal stroke tolerance from days to months. Microarray (Illumina) analyses were performed on microvessel-enriched fractions of adult mouse brain obtained from the following five groups (naïve; HX1-3h; HX1-2days; HX9-3h; HX9-2days). Differentially expressed genes were analyzed bioinformatically using Ingenuity Pathway Analysis software, with qPCR validating selected up- and down-regulated genes. As expected, some differentially expressed genes were common to more than one treatment or time point, whereas others were unique to treatment or time point. Bioinformatic analyses provided insights into acute (3h) inflammatory and immune signaling pathways that may be differentially activated by HX1 and HX9, with anti-inflammatory and trophic pathways coincident with the ischemia-tolerant phenotype two days after HX1. Interestingly, two days after HX9, microvessels were transcriptionally silent, with only five genes remaining differentially expressed relative to naïve mice. Our microarray findings and bioinformatic analyses suggest that cerebral microvessels from HX1-treated mice exhibit early activation of immune system signaling that is largely suppressed in microvessels from HX9-treated mice. These and other differences between these responses require further study, including at the proteomic level, and with pharmacologic and genetic experiments designed to reveal causality, to reveal further insights into the mechanisms underlying long-lasting stroke tolerance.

Intermittent Hypoxia Promotes Functional Neuroprotection from Retinal Ischemia in Untreated First-Generation Offspring: Proteomic Mechanistic Insights

Purpose

Stress can lead to short- or long-term changes in phenotype. Accumulating evidence also supports the transmission of maladaptive phenotypes, induced by adverse stressors, through the germline to manifest in subsequent generations, providing a novel mechanistic basis for the heritability of disease. In the present study in mice, we tested the hypothesis that repeated presentations of a nonharmful conditioning stress, demonstrated previously to protect against retinal ischemia, will also provide ischemic protection in the retinae of their untreated, first-generation (F1) adult offspring.

Methods

Swiss-Webster ND4 outbred mice were mated following a 16-week period of brief, every-other-day conditioning exposures to mild systemic hypoxia (repetitive hypoxic conditioning, RHC). Retinae of their 5-month-old F1 progeny were subjected to unilateral ischemia. Scotopic electroretinography quantified postischemic outcomes. The injury-resilient retinal proteome was revealed by quantitative mass spectrometry, and bioinformatic analyses identified the biochemical pathways and networks in which these differentially expressed proteins operate.

Results

Significant resilience to injury in both sexes was documented in F1 mice derived from RHC-treated parents, relative to matched F1 adult progeny derived from normoxic control parents. Ischemia-induced increases and decreases in the expression of many visual transduction proteins that are integral to photoreceptor function were abrogated by parental RHC, providing a molecular basis for the observed functional protection.

Conclusions

Our proteomic analyses provided mechanistic insights into the molecular manifestation of the inherited, injury-resilient phenotype. To our knowledge, this is the first study in a mammalian model documenting the reprogramming of heritability to promote disease resilience in the next generation.

Intra- and intergenerational changes in the cortical DNA methylome in response to therapeutic intermittent hypoxia in mice

Recent evidence from our laboratory documents functional resilience to retinal ischemic injury in untreated mice derived from parents exposed to repetitive hypoxic conditioning (RHC) before breeding. To begin to understand the epigenetic basis of this intergenerational protection, we used methylated DNA immunoprecipitation and sequencing to identify genes with differentially methylated promoters (DMGPs) in the prefrontal cortex of mice treated directly with the same RHC stimulus (F0-RHC) and in the prefrontal cortex of their untreated F1-generation offspring (F1-*RHC). Subsequent bioinformatic analyses provided key mechanistic insights into how changes in gene expression secondary to promoter hypo- and hypermethylation might afford such protection within and across generations. We found extensive changes in DNA methylation in both generations consistent with the expression of many survival-promoting genes, with twice the number of DMGPs in the cortex of F1*RHC mice relative to their F0 parents that were directly exposed to RHC. In contrast to our hypothesis that similar epigenetic modifications would be realized in the cortices of both F0-RHC and F1-*RHC mice, we instead found relatively few DMGPs common to both generations; in fact, each generation manifested expected injury resilience via distinctly unique gene expression profiles. Whereas in the cortex of F0-RHC mice, predicted protein-protein interactions reflected activation of an anti-ischemic phenotype, networks activated in F1-*RHC cortex comprised networks indicative of a much broader cytoprotective phenotype. Altogether, our results suggest that the intergenerational transfer of an acquired phenotype to offspring does not necessarily require the faithful recapitulation of the conditioning-modified DNA methylome of the parent.

Comprehensive characterization of the adult ND4 Swiss Webster mouse retina: Using discovery-based mass spectrometry to decipher the total proteome and phosphoproteome

Purpose

Diverse groups of proteins play integral roles in both the physiology and pathophysiology of the retina. However, thorough proteomic analyses of retinas of experimental species are currently unavailable. The purpose of the present paper is providing the field with a comprehensive proteomic characterization of the retina of a commonly used laboratory mouse using a discovery-based mass spectrometry (MS) approach.

Methods

Retinas from eight male and eight female 30-week-old outbred ND4 Swiss Webster mice were harvested and immediately processed for MS analysis on a Thermo Fisher (TF) Fusion Orbitrap MS. The retinal proteome and phosphoproteome were identified and subsequently analyzed using Proteome Discoverer 2.2 and Panther-GeneGo. SEQUEST-HT scoring was used for analysis, and the reference protein FASTA database was from Mus musculus. Specifically, three technical repeats were performed for each biological sample. For characterization, only high-scoring peptides were considered, with a false discovery rate (FDR) of <1%. Downstream bioinformatic analysis used Ingenuity Pathway Analysis (IPA; Qiagen).

Results

Using Proteome Discoverer 2.2, 4,767 different proteins were identified and segregated into 26 major protein classes, 9 functional molecular classes, and 12 categories of biological processes. The five largest protein classes included the following: nucleic acid binding (17%), hydrolases (13%), enzyme modulators (10%), transferases (9%), and oxidoreductases (6%). "Binding" and "catalytic" proteins contributed to 81% of the molecular function class at 37% and 42%, respectively. "Cellular processing" and "metabolic processes" contributed the most to biologic activity, at 31% and 26%, respectively. Phosphopeptide enrichment yielded the identification of 610 additional unique proteins that were not originally identified. The two datasets combined produced an adult mouse retinal proteome consisting of 5,377 unique proteins. Overall, 41% of the retinal proteome was phosphorylated. The overwhelming diversity of retinal protein functionality was reflected through further analyses revealing 2,086 unique pathway hits across 241 different pathways (TF). A core analysis summary report was performed in IPA (Qiagen) to analyze the top signaling networks, protein-protein interaction (PPI) enrichments, and canonical pathways.

Conclusions

Using this high-throughput technique, we have further deciphered and updated the diverse proteome of the mouse retina, including the phosphoproteome, thereby providing the most comprehensive proteomic profile for this tissue known to date. These findings, and the bioinformatic analyses we also provided, establish a platform for future studies, facilitating the elucidation of the relevance of these proteins to the molecular and cellular pathologies that underlie retinal function and disease.

The universal, situational, and personal needs of cancer patients and their main carers

The importance of psychosocial factors in the cancer journey for both patients and their carers has been recognised in UK health policy. The aim of this paper is to consider--(1) which needs are regarded as important by patients and their carers; (2) which are the unmet needs of patients and their carers. The study focuses on the responses of 233 paired cancer patients and their carers derived from a cross-sectional questionnaire survey in three health authorities in North West England. The majority of patient-carer pairs expressed the importance of having good relationships with health-care professionals and receiving good-quality information. These can be identified as "universal" needs. A minority of patient-carer pairs expressed the importance of other kinds of needs. These items were mainly to do with managing daily life, emotions, and social identity and can be identified as "situational" or "personal" needs. Where there were discrepancies between patients and carers, patients were likely to identify more needs as important. In contrast, carers have more unmet needs, reflecting their comparative neglect. Broadly, "universal" needs are being met, but "situational" and "personal" needs, particularly among carers, are relatively unmet and require greater attention on the part of nurses and primary care professionals.

Psychosocial needs in cancer patients related to religious belief

In a study of psychosocial needs amongst cancer patients, the possession of a religious faith has been identified as a significant factor in determining a range of psychosocial needs. Of the 354 respondents to a questionnaire, which included a comprehensive psychosocial needs inventory, 83% said they had a religious faith, and in general these patients were less reliant on health professionals, had less need for information, attached less importance to the maintenance of independence and had less need for help with feelings of guilt, with their sexuality or with some practical matters than those who said they had no religious faith. In addition, they had fewer unmet needs overall (32% compared with 52%). The knowledge of a patient's spirituality should help service providers to predict aspects of psychosocial need and to respond sensitively and appropriately to a patient's experience of cancer.

Cancer and faith. Having faith--does it make a difference among patients and their informal carers?

This research considers the impact of having a religious faith on the cancer experience of patients and informal carers, focusing primarily on the association between faith and psychosocial needs. A questionnaire survey of 1000 patients in the north-west of England returned 402 completed questionnaires; around two-thirds of patients indicated they had an informal carer. Using logistic regression analysis, we examine the relationship between the importance of 48 needs and faith for 189 paired patients and carers, while controlling for the effect of eight socio-demographic and clinical variables. Patients with expressed faith identified fewer psychosocial needs than those without faith. In contrast, carers with expressed faith identified more needs than those without faith in relation to support from family and neighbours. Carers also needed more help with finding a sense of purpose and meaning, and help in dealing with unpredictability. Not surprisingly, both patients and carers with faith identified a greater need for opportunities for personal prayer, support from people of their own faith and support from a spiritual adviser. Various explanations of these differences between patients and carers are proposed. The crucial point is that one should not too readily assume that the cancer experience is shared in the same way by patients and carers. In understanding the faith dimension, one needs to consider both the spiritual and secular aspects of having a religious faith.

Informal carers of cancer patients: what are their unmet psychosocial needs?

This paper considers the significant unmet psychosocial needs of the informal carers of cancer patients, drawing on data generated in a 3-year UK study (1997-2000) on the psychosocial needs of cancer patients and their main carers. While the needs of the carers of cancer patients are increasingly being recognised in healthcare policy documents, there is relatively little published literature on these needs. A "significant unmet need" is defined here as a need deemed important by the carer, but which has not been met. A descriptive cross-sectional survey of carers was conducted and the responses of 195 carers relating to 48 psychosocial need items were analysed. A subset of these carers (n = 32) were interviewed. Forty-three per cent of carers had significant unmet needs. They were more likely to be those where the relationship to the patient was not that of a partner or spouse, more likely to have other caring responsibilities, and less likely to have friends or relations to call upon for help. Carers with unmet needs were also more likely to be in poor health themselves or to be caring for a patient who had reached the palliation-only phase in their cancer journey. The majority of carers expressed the importance of needs such as having good relationships with healthcare professionals and receiving honest information, but few expressed dissatisfaction with these aspects of need. Items of significant unmet need clustered around aspects of managing daily life, emotions, and also social identity for a sizeable minority of carers. These are the same areas of significant unmet need that concern patients. However, carers have more of these concerns, reflecting their comparative neglect. The paper also considers how these widespread concerns can be addressed.

Partial tolerance in rat renal allograft recipients following multiple blood transfusions and concomitant cyclosporine

Multiple prior administrations of donor-strain blood while under limited cyclosporine cover, consistently induce extensive rat renal allograft survival and transplantation tolerance. Yet it was hypothesized that some chronic rejection mechanisms were nevertheless operative since consistent but nonprogressive minor renal dysfunction was observed long-term. A histopathologic study on these putative tolerant rats was undertaken to test this hypothesis. Twenty long-term LEW recipients of BN renal allografts receiving the blood-CsA regimen were examined histopathologically at day 100 post-transplant. Sixteen control LEW recipients receiving only a BN renal allograft were studied acutely at day 7 posttransplant. The control recipients demonstrated a range of lesions consistent with previous studies on acute renal allograft rejection in the rat. However, tolerant recipients demonstrated mild-to-moderate lesions consistent with chronic mechanisms of rejection including the following: moderate focal interstitial mononuclear inflammatory cellular infiltration, with periglomerular and perivascular accumulation; occasional arteriolar luminal obliteration and glomerular atrophy; focal areas of moderate interstitial fibrosis; mild interstitial hemorrhage; mild-to-moderate tubular atrophy; and focal tubular necrosis. Previously our laboratory has documented that tissue-specific renal basement membrane antigens may be responsible for inciting this pattern of focal chronic interstitial inflammation. However, from the present histopathologic studies, it would appear likely that chronic rejection mechanisms in these recipients, which were defined as tolerant by immunologic criteria, involve both tissue-specific and MHC determinants. Therefore, induction of transplantation tolerance in these indefinite survivors is partial or incomplete.

Lactate kinetics in exercising Thoroughbred horses: regulation of turnover rate in plasma

Plasma lactate turnover rate of Thoroughbred racehorses was measured by bolus injection of [U-14C]lactate at rest and two levels of submaximal treadmill exercise (3-4 m/s trot, 6% incline, and 6.5 m/s horizontal canter). Our goals were 1) to determine the relative effects of changes in cardiac output and in plasma lactate concentration on turnover rate [using cardiac output data from Weber et al. (28)] and 2) to assess the importance of lactate as a metabolic fuel in a trained animal athlete. Lactate turnover rates were 9.3 mumol.min-1.kg-1 (rest), 75.9 mumol.min-1.kg-1 at the beginning of the trot protocol [45% maximum O2 uptake (VO2max)], 50.3 mumol.min-1.kg-1 later in the same protocol (50% VO2max), and 66.1 mumol.min-1.kg-1 during the canter protocol (55% VO2max). Both changes in cardiac output and in plasma lactate concentration had a significant effect on turnover rate. Variation in plasma lactate fluxes of Thoroughbreds during exercise follows the standard mammalian pattern, but this substrate only plays a minor role as an oxidizable fuel in horses. The oxidation of plasma lactate accounts for less than 5% of metabolic rate (VO2) during submaximal work. Adjustments in cardiac output and in metabolite concentration represent, respectively, the coarse and fine controls for the regulation of plasma metabolite turnover rate.

Cardiac output and oxygen consumption in exercising Thoroughbred horses

This study characterizes the effects of exercise on the cardiac output (Q) and the metabolic rate (VO2) of trained Thoroughbred racehorses. Heart rate, Q, and arteriovenous (a-v)O2 difference were measured at rest and at three levels of submaximal treadmill exercise (1.6 m/s walk and 3-4 m/s trot at 6% incline, and 6.5 m/s horizontal canter). Heart rate and (a-v)O2 difference were also measured during maximal exercise (12.5 m/s gallop, 5% incline) to obtain an estimate of maximum O2 uptake (VO2max). The walk, trot, and canter represented 25, 45, and 55% VO2max. Mean heart rate went from 48.9 (rest) to 197 beats/min (gallop). Q ranged from 106 (rest) to 571 ml.min-1.kg-1 (canter), and stroke volume went from 1.34 (rest) to a maximum of 1.58 liters (walk). Thoroughbreds were able to bring hematocrit from 38 (rest) to 63% (gallop), and this adjustment allowed them to reach an impressive (a-v)O2 difference of 23 vol%, which represents a fivefold increase over resting values. These outstanding athletes probably support an aerobic scope of 40-fold.