Milk microbiome in the first month of lactation and at weaning from ewes supplemented with zinc pre- and postpartum.

Mastitis is an important disease with economic and welfare implications in both clinical and subclinical states. The aim of this research was to sequence the hypervariable V4 region of the 16S rRNA gene to describe the microbial diversity and taxonomy of milk from clinically healthy ewes (Rambouillet, WF = 9; Hampshire, BF = 5). Experimental ewes represented a subset of a larger study assessing the impacts of divergent dietary zinc (Zn) concentrations [1× National Academics of Sciences, Engineering, and Medicine (NASEM) recommendations = CON or 3× NASEM recommendations = ZnTRT] throughout late gestation and lactation. Milk was collected at four periods during early lactation (18 - 24 h, 7 d, 14 d, and 21 d postpartum) and at weaning (84 ± 14 d postpartum). Somatic cell counts (SCC) were quantified, averaged, and classed (low: < 500 × 103; medium: 500 × 103 - 100 × 104; high: > 100 × 104 cells/mL). Milk samples (n = 67) were sequenced to identify bacteria and archaea; the most abundant phyla were Actinobacteria, Bacteroidetes, Cyanobacteria, Euryarchaeota, Firmicutes, Fusobacteria, Lentisphaerae, Proteobacteria, Spirochaetes, Tenericutes, Saccharibacteria TM7, and Verrucomicrobia. Mastitis pathogens were among the most relatively abundant genera, including Staphylococcus, Mannheimia, Corynebacterium, and Pseudomonas. Effects of breed, dietary Zn concentration, SCC class, and their two-way interactions on milk microbiome diversity and taxonomy were assessed within early lactation (using a repeated measures model) and weaning samples. Alpha-diversity metrics included Pielou's evenness, Faith's phylogenetic diversity, and Shannon's entropy indices. Main and interactive effects between Zn treatment, breed, SCC class, and period were variable in early lactation and not evident in weaning samples. Milk from BF ewes had increased Faith's phylogenetic diversity and Shannon's entropy, and differed in unweighted UniFrac composition (P ≤ 0.10). Milk from CON ewes had a reduced rate of composition change through early lactation (P = 0.02) indicating greater microbiome stability than ZnTRT ewe milk. These results support that milk is not sterile, and breed, dietary Zn concentration, and SCC class variably affect the milk microbiome. Findings from the current study provide important foundational insights into the effects of increased dietary Zn supplementation on longitudinal changes in the milk microbiome and associations with mammary gland health and mastitis.

Enrichment of Bioactive Lipids in Urinary Extracellular Vesicles and Evidence of Apoptosis in Kidneys of Hypertensive Diabetic Cathepsin B Knockout Mice after Streptozotocin Treatment.

Cathepsin B (CtsB) is a ubiquitously expressed cysteine protease that plays important roles in health and disease. Urinary extracellular vesicles (uEVs) are released from cells associated with urinary organs. The antibiotic streptozotocin (STZ) is known to induce pancreatic islet beta cell destruction, diabetic nephropathy, and hypertension. We hypothesized that streptozotocin-induced diabetic kidney disease and hypertension result in the release of bioactive lipids from kidney cells that induce oxidative stress and renal cell death. Lipidomics was performed on uEVs isolated from CtsB knockout mice treated with or without STZ, and their kidneys were used to investigate changes in proteins associated with cell death. Lysophosphatidylethanolamine (LPE) (18:1), lysophosphatidylserine (LPS) (22:6), and lysophosphatidylglycerol (LPG) (22:5) were among the bioactive lipids enriched in uEVs from CtsB knockout mice treated with STZ compared to untreated CtsB mice (n = 3 uEV preparations per group). Anti-oxidant programming was activated in the kidneys of the CtsB knockout mice treated with STZ, as indicated by increased expression of glutathione peroxidase 4 (GPX4) and the cystine/glutamate antiporter SLC7A11 (XCT) (n = 4 mice per group), which was supported by a higher reactivity to 4-hydroxy-2-nonenal (4-HNE), a marker for oxidative stress (n = 3 mice per group). Apoptosis but not ferroptosis was the ongoing form of cell death in these kidneys as cleaved caspase-3 levels were significantly elevated in the STZ-treated CtsB knockout mice (n = 4 mice per group). There were no appreciable differences in the pro-ferroptosis enzyme acyl-CoA synthetase long-chain family member 4 (ACSL4) or the inflammatory marker CD93 in the kidneys (n = 3 mice per group), which further supports apoptosis as the prevalent mechanism of pathology. These data suggest that STZ treatment leads to oxidative stress, inducing apoptotic injury in the kidneys during the development of diabetic kidney disease and hypertension.

A Call for PrEP Discussions With Black Women-Be a Gardener.

This Viewpoint discusses the importance of proactively discussing preexposure prophylaxis (PrEP) with Black cisgender women.

Avoiding Shots in the Dark: Learning from the Past To Inform the Implementation of Long-Acting Injectable Pre-Exposure Prophylaxis for Black American Cisgender Women.

The FDA's approval of long-acting injectable cabotegravir pre-exposure prophylaxis (LAI PrEP) as an alternative to daily oral PrEP represents a crucial development in HIV prevention, particularly for American Black cisgender women who face high HIV-1 risks. Yet, uptake may be hindered by racial and gender inequities. Addressing these requires learning from the roll-out of oral PrEP, creating culturally tailored PrEP campaigns, and enhancing provider training to meet Black women's needs. Tools for discussing PrEP within personal relationships and product preference research tailored to Black women's needs are essential for effective LAI PrEP delivery. Deliberative implementation of LAI PrEP must employ strategies that are community-sensitive, -responsive, and -inclusive. It should prioritize the incorporation of Black women's voices in decision-making and should promote community-led strategies. By addressing historical injustices and fostering trust, healthcare systems can enhance LAI PrEP uptake by Black women. Emphasizing a community-centered approach that ensures health equity and acknowledges the crucial role that social media and Black-led organizations play in promoting PrEP awareness and adoption within Black communities is necessary for successful implementation.

Using stated preference methods to facilitate knowledge translation in implementation science.

Enhancing the arsenal of methods available to shape implementation strategies and bolster knowledge translation is imperative. Stated preference methods, including discrete choice experiments (DCE) and best-worst scaling (BWS), rooted in economics, emerge as robust, theory-driven tools for understanding and influencing the behaviors of both recipients and providers of innovation. This commentary outlines the wide-ranging application of stated preference methods across the implementation continuum, ushering in effective knowledge translation. The prospects for utilizing these methods within implementation science encompass (1) refining and tailoring intervention and implementation strategies, (2) exploring the relative importance of implementation determinants, (3) identifying critical outcomes for key decision-makers, and 4) informing policy prioritization. Operationalizing findings from stated preference research holds the potential to precisely align health products and services with the requisites of patients, providers, communities, and policymakers, thereby realizing equitable impact.

Tuning Molecular Motion Enhances Intrinsic Fluorescence in Peptide Amphiphile Nanofibers.

Peptide amphiphiles (PAs) are highly tunable molecules that were recently found to exhibit aggregation-induced emission (AIE) when they self-assemble into nanofibers. Here, we leverage decades of molecular design and self-assembly study of PAs to strategically tune their molecular motion within nanofibers to enhance AIE, making them a highly useful platform for applications such as sensing, bioimaging, or materials property characterization. Since AIE increases when aggregated molecules are rigidly and closely packed, we altered the four most closely packed amino acids nearest to the hydrophobic core by varying the order and composition of glycine, alanine, and valine pairs. Of the six PA designs studied, C16VVAAK2 had the highest quantum yield at 0.17, which is a more than 10-fold increase from other PA designs including the very similar C16AAVVK2, highlighting the importance of precise amino acid placement to anchor rigidity closest to the core. We also altered temperature to increase AIE. C16VVAAK2 exhibited an additional 4-fold increase in maximum fluorescence intensity when the temperature was raised from 5 to 65 °C. As the temperature increased, the secondary structure transitioned from ß-sheet to random coil, indicating that further packing an already aligned molecular system makes it even more readily able to transfer energy between the electron-rich amides. This work both unveils a highly fluorescent AIE PA system design and sheds insights into the molecular orientation and packing design traits that can significantly enhance AIE in self-assembling systems.

Symptomatic hypercalcemia in an infant secondary to excessive consumption of almond milk as a formula alternative.

A 4-month-old previously healthy female presented with persistent nonbloody, nonbilious emesis, decreased urine output, weight loss, fussiness, and lethargy. Serum levels of calcium were increased at 14.1 mg/dL, serum phosphate decreased at 1.6 mg/dL, and serum parathyroid hormone decreased at <4 pg/mL. The patient had been consuming unsweetened almond milk due to inability to find infant formula during a national infant formula shortage. Milk alternatives including almond milk are calorie-poor, low fat, low protein, and too high in free water and calcium to safely be the primary nutrition source for infants.

Synthetic and Computational Design Insights toward Mimicking Protein Binding of Phosphate.

The unique and precise capabilities of proteins are renowned for their specificity and range of application. Effective mimicking of protein-binding offers enticing potential to direct their abilities toward useful applications, but it is nevertheless quite difficult to realize this characteristic of protein behavior in a synthetic material. Here, we design, synthesize, and evaluate experimentally and computationally a series of multicomponent phosphate-binding peptide amphiphile micelles to derive design insights into how protein binding behavior translates to synthetic materials. By inserting the Walker A P-loop binding motif into this peptide synthetic material, we successfully implemented the protein-binding design parameters of hydrogen-bonding and electrostatic interaction to bind phosphate completely and selectively in this highly tunable synthetic platform. Moreover, in this densely arrayed peptide environment, we use molecular dynamics simulations to identify an intriguing mechanistic shift of binding that is inaccessible in traditional proteins, introducing two corresponding new design elements─flexibility and minimization of the loss of entropy due to ion binding, in protein-analogous synthetic materials. We then translate these new design factors to de novo peptide sequences that bind phosphate independent of protein-extracted sequence or conformation. Overall, this work reveals that traditional complex conformational restrictions of binding by proteins can be replaced and repurposed in a multicomponent peptide amphiphile synthetic material, opening up opportunities for future enhanced protein-inspired design.

Social and structural factors associated with interest in HIV preexposure prophylaxis among Black women in the United States.

In a nationwide sample of cisgender Black women in the US, we assessed the associations between social and structural factors and interest in using HIV preexposure prophylaxis (PrEP). Among 315 respondents, 62.2% were interested in PrEP if it were provided for free. Positive social norms surrounding PrEP, including injunctive norms (perceived social acceptability of PrEP use) and descriptive norms (perceived commonality of PrEP use), were positively associated with interest in using PrEP. Concerns about HIV infection, recently visiting a health care provider, and comfort discussing PrEP with a provider were also positively associated with interest in using PrEP. Anticipating PrEP disapproval from others was negatively associated with interest in PrEP. Although PrEP can promote autonomy and personal discretion, Black women's PrEP-related decisions occur in a complex social environment. Black women may benefit from interventions to promote positive norms and attitudes surrounding PrEP at the community level and empower them in discussions with their providers about PrEP.

The Impact of Providers as Health Discussants on Black Women's Interest in PrEP for HIV Prevention.

This study sought to examine the role of providers as health discussants (HD) on interest in preexposure prophylaxis for HIV prevention in a national sample of adult Black cisgender women (N = 315). Health discussant networks, a type of social network, may be influential in HIV prevention efforts. These networks, often composed of individuals' families, have improved health utilization outcomes in other disciplines. However, health discussants in HIV prevention are understudied, especially when considering providers as network members. We conducted a cross-sectional online survey and collected socio-demographic information, sexual history, HIV concerns, PrEP attitudes, healthcare utilization, mistrust, social support, and HD information. We used descriptive statistics and logistic regression to analyze data. Associations between PrEP interest and variables were examined. We found that older, partnered, who had recent healthcare visits or health insurance were more likely to involve healthcare providers as discussants. Anticipated PrEP stigma decreased provider involvement. Among participants listing providers as discussants, there was a greater likelihood of interest in using PrEP. Our findings indicate that healthcare provider support and social factors are crucial in promoting PrEP engagement among Black women. Integrating social dynamics and positive provider-patient interactions is essential for successful PrEP implementation.

"Just the Stigma Associated with PrEP Makes You Feel Like It's HIV Itself": Exploring PrEP Stigma, Skepticism, and Medical Mistrust Among Black Cisgender Women in Urban and Rural Counties in the U.S. Deep South.

Despite its effectiveness in HIV prevention, PrEP use among Black women is suboptimal. Notably in the Deep South, Black women have the lowest PrEP uptake rates among all US regions. To increase PrEP engagement, research suggests the implementation of structural and social interventions particular to the needs of Black women. The state of Alabama is of priority to federal HIV prevention initiatives; therefore, this study conducted focus groups among 47 cis-gender Black women in rural and urban Alabama counties, with the highest statewide HIV incidence rates, to understand perceptions of PrEP and decision-making processes. Deductive coding analysis was conducted and themes were finalized based on consensus among the two coders. Four themes were identified. Findings show stigma undergirds Alabaman Black women's decisions to engage in PrEP care. Moreover, women reported stigma stifled community-level education about PrEP. Despite these experiences, education was regarded as a strategy to decrease stigma and PrEP skepticism, the latter of which emerged as a prominent theme. Medical mistrust and healthcare engagement were the other emergent themes influencing participation in PrEP care. To ensure PrEP efforts meet the needs of Black cisgender women in Alabama counties, interventions must address longstanding stigma, increase educational initiatives, and ensure interventions consider women's experiences with medical mistrust and health care engagement.

Mayaro virus pathogenesis and immunity in rhesus macaques.

Mayaro virus (MAYV) is a mosquito-transmitted alphavirus that causes debilitating and persistent arthritogenic disease. While MAYV was previously reported to infect non-human primates (NHP), characterization of MAYV pathogenesis is currently lacking. Therefore, in this study we characterized MAYV infection and immunity in rhesus macaques. To inform the selection of a viral strain for NHP experiments, we evaluated five MAYV strains in C57BL/6 mice and showed that MAYV strain BeAr505411 induced robust tissue dissemination and disease. Three male rhesus macaques were subcutaneously challenged with 105 plaque-forming units of this strain into the arms. Peak plasma viremia occurred at 2 days post-infection (dpi). NHPs were taken to necropsy at 10 dpi to assess viral dissemination, which included the muscles and joints, lymphoid tissues, major organs, male reproductive tissues, as well as peripheral and central nervous system tissues. Histological examination demonstrated that MAYV infection was associated with appendicular joint and muscle inflammation as well as presence of perivascular inflammation in a wide variety of tissues. One animal developed a maculopapular rash and two NHP had viral RNA detected in upper torso skin samples, which was associated with the presence of perivascular and perifollicular lymphocytic aggregation. Analysis of longitudinal peripheral blood samples indicated a robust innate and adaptive immune activation, including the presence of anti-MAYV neutralizing antibodies with activity against related Una virus and chikungunya virus. Inflammatory cytokines and monocyte activation also peaked coincident with viremia, which was well supported by our transcriptomic analysis highlighting enrichment of interferon signaling and other antiviral processes at 2 days post MAYV infection. The rhesus macaque model of MAYV infection recapitulates many of the aspects of human infection and is poised to facilitate the evaluation of novel therapies and vaccines targeting this re-emerging virus.

Identifying what works for whom: Implementation outcomes following iLookOut, a child abuse identification and referral training program.

Introduction: iLookOut, a web-based child abuse training for early childcare professionals (ECPs), has been shown to improve knowledge and attitudes related to correctly identifying and reporting suspected cases of child abuse. The overarching goal of the present study is to examine "what works for whom" for iLookOut in order to identify strategies for optimizing learner outcomes. Methods: This prospective study enrolled 12,705 ECPs who completed iLookOut (November 2014-December 2018). We used structural equation models to test whether learner demographic and professional characteristics were differentially associated with implementation outcomes (i.e., acceptability and appropriateness) and whether these mediated subsequent indicators of training effectiveness (i.e., gains in knowledge). Results: Consistent with previous research, individuals with lower baseline knowledge scores showed greater knowledge gains (ß = -.57; p < .001). Greater knowledge gains were seen for learners who reported higher acceptability (ß = .08; p < .001) or appropriateness (ß = .14; p < .001). Implementation outcomes strongly associated with knowledge gains included acceptability for female learners and appropriateness for learners who had not completed high school or had >15 years of experience in childcare settings. Where mediation was found, for the majority of groups, appropriateness emerged as the driving mediator. Conclusion: Implementation outcomes emerged as important drivers of knowledge change for most groups. The iLookOut Core Training's use of a multimedia learning environment, video-based storylines, and game-based techniques were endorsed by learners and correlated with increases in knowledge. Future work should explore why aspects of the iLookOut training are rated as less acceptable or appropriate by some groups and what changes would improve efficacy for low performing learners.

Pathways and Intersections: Multifaceted Approaches to Engage Individuals From Underrepresented and Marginalized Communities in HIV Research and Career Development.

BACKGROUND: The underrepresentation of historically marginalized groups in the HIV research workforce is a barrier to reaching national Ending the Epidemic goals. SETTING: The Harvard University Center for AIDS Research (HU CFAR) Diversity Equity and Inclusion Working Group (DEI WG) uses a multifaceted approach to enhance the field's diversity. METHODS: We established a DEI WG to improve the recruitment, inclusion, and retention of underrepresented minorities (URMs) in HIV research. We use community-based, participatory processes to establish and expand education and outreach programs about HIV care and research to better connect the HU CFAR to communities affected by HIV. This article reports on the development of the WG in July 2022, progress in its first year, and future plans. RESULTS: We have built a network of >50 investigators across the university for monthly meetings; partnered with existing research pathway programs for high school, undergraduate, and graduate students, directly supporting 7 new trainees and linking CFAR investigators to additional mentorship opportunities; and created 2-year Scholar Awards for 5 URM investigators in HIV. Planned work includes needs assessments for early-stage investigators to understand factors contributing to inclusion and retention and new pathway and outreach programming being developed with community partner minority-serving institutions. CONCLUSIONS: The HU CFAR DEI WG strives to ensure that individuals from underrepresented, marginalized, and minoritized communities have an opportunity to contribute to HIV research and that research is informed by the needs of the communities affected by the epidemic. An intersectional approach should be incorporated into HIV research pathway initiatives.

Factors Associated with Comfort Discussing PrEP with Healthcare Providers among Black Cisgender Women.

Preexposure prophylaxis (PrEP) for HIV prevention uptake remains low among Black cisgender women in the United States, despite their disproportionate HIV burden. This study aimed to examine factors associated with Black women's comfort discussing PrEP with healthcare providers and its link to their interest in PrEP use. A cross-sectional survey was conducted with a national sample of 315 Black cisgender women. Descriptive statistics and logistic regression models were utilized for data analysis. The results showed that 79% of Black women felt comfortable discussing PrEP with their healthcare provider. Age, recent healthcare provider visit, interest in PrEP, and positive social norms were associated with increased odds of comfort in discussing PrEP, while anticipated PrEP disapproval and stigma were associated with decreased odds. Older age was related to greater comfort, potentially due to increased familiarity and self-efficacy in discussing sexual health. Recent healthcare utilization indicated positive provider relationships, facilitating discussions about sexual health. Anticipating support from social networks positively influenced comfort levels. Conversely, PrEP-related stigma and anticipated disapproval were barriers to comfort. These findings highlight the importance of provider-patient communication and social support in facilitating PrEP engagement among Black cisgender women. Interventions should consider age-appropriate strategies and address structural and provider biases to improve PrEP discussions and promote HIV prevention.

Maximizing Microsampling: Measurement of Comprehensive Metabolic and Lipid Panels Using a Novel Capillary Blood Collection Device.

BACKGROUND: Demand continues to grow for patient-centric sampling solutions that enable collection of small volumes of blood outside of healthcare facilities. Various technologies have been developed to facilitate sample collection but gaps in knowledge remain, preventing these technologies from replacing standard venipuncture. METHODS: A novel blood collection device, Touch Activated Phlebotomy (TAP) II® from YourBio Health, and standard fingerstick collection using a BD Microtainer® were utilized to collect capillary serum samples. Measurements of a comprehensive metabolic and lipid panels were measured on these samples and compared to results from venous serum samples that were collected in parallel. Hemolysis was used to assess sample quality. Sample volumes obtained from self-collected TAP II samples were also determined. RESULTS: Correlation of capillary serum with respect to venous serum was demonstrated (R > 0.9) for professionally collected TAP II samples, self-collected TAP II samples, and professionally collected fingerstick samples for alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, cholesterol, high-density lipoprotein, total bilirubin, and triglycerides. Results for creatinine demonstrated acceptable correlation, however, a consistent negative bias was observed. Biases (with unacceptable correlations) were also observed for measurements of carbon dioxide and potassium. Correlative results for albumin were not consistently acceptable across the collection techniques utilized while the remaining analytes tested did not demonstrate acceptable correlations under any condition. Correlation results, however, would improve with a wider distribution of analyte concentrations. CONCLUSIONS: Collections of small volumes of liquid blood continue to show potential as a patient-centric solution.

Allogeneic immunity clears latent virus following allogeneic stem cell transplantation in SIV-infected ART-suppressed macaques.

Allogeneic hematopoietic stem cell transplantation (alloHSCT) from donors lacking C-C chemokine receptor 5 (CCR5Δ32/Δ32) can cure HIV, yet mechanisms remain speculative. To define how alloHSCT mediates HIV cure, we performed MHC-matched alloHSCT in SIV+, anti-retroviral therapy (ART)-suppressed Mauritian cynomolgus macaques (MCMs) and demonstrated that allogeneic immunity was the major driver of reservoir clearance, occurring first in peripheral blood, then peripheral lymph nodes, and finally in mesenteric lymph nodes draining the gastrointestinal tract. While allogeneic immunity could extirpate the latent viral reservoir and did so in two alloHSCT-recipient MCMs that remained aviremic >2.5 years after stopping ART, in other cases, it was insufficient without protection of engrafting cells afforded by CCR5-deficiency, as CCR5-tropic virus spread to donor CD4+ T cells despite full ART suppression. These data demonstrate the individual contributions of allogeneic immunity and CCR5 deficiency to HIV cure and support defining targets of alloimmunity for curative strategies independent of HSCT.

Infection with chikungunya virus confers heterotypic cross-neutralizing antibodies and memory B-cells against other arthritogenic alphaviruses predominantly through the B domain of the E2 glycoprotein.

Infections with Chikungunya virus, a mosquito-borne alphavirus, cause an acute febrile syndrome often followed by chronic arthritis that persists for months to years post-infection. Neutralizing antibodies are the primary immune correlate of protection elicited by infection, and the major goal of vaccinations in development. Using convalescent blood samples collected from both endemic and non-endemic human subjects at multiple timepoints following suspected or confirmed chikungunya infection, we identified antibodies with broad neutralizing properties against other alphaviruses within the Semliki Forest complex. Cross-neutralization generally did not extend to the Venezuelan Equine Encephalitis virus (VEEV) complex, although some subjects had low levels of VEEV-neutralizing antibodies. This suggests that broadly neutralizing antibodies elicited following natural infection are largely complex restricted. In addition to serology, we also performed memory B-cell analysis, finding chikungunya-specific memory B-cells in all subjects in this study as remotely as 24 years post-infection. We functionally assessed the ability of memory B-cell derived antibodies to bind to chikungunya virus, and related Mayaro virus, as well as the highly conserved B domain of the E2 glycoprotein thought to contribute to cross-reactivity between related Old-World alphaviruses. To specifically assess the role of the E2 B domain in cross-neutralization, we depleted Mayaro and Chikungunya virus E2 B domain specific antibodies from convalescent sera, finding E2B depletion significantly decreases Mayaro virus specific cross-neutralizing antibody titers with no significant effect on chikungunya virus neutralization, indicating that the E2 B domain is a key target of cross-neutralizing and potentially cross-protective neutralizing antibodies.

Metformin Alleviates Diabetes-Associated Hypertension by Attenuating the Renal Epithelial Sodium Channel.

Diabetic nephropathy is the primary cause of morbidity in type 2 diabetes mellitus (T2DM) patients. New data indicate that hypertension, a common comorbidity in T2DM, can worsen outcomes of diabetic nephropathy. While metformin is a commonly prescribed drug for treating type 2 diabetes, its blood pressure regulating ability is not well documented. The aim of this study was to investigate the effect of metformin on normalizing blood pressure in salt-loaded hypertensive diabetic db/db mice. Sixteen-week-old male and female diabetic db/db mice were individually placed in metabolic cages and then randomized to a control vehicle (saline) or metformin treatment group. We evaluated the blood pressure reducing ability of metformin in salt-induced hypertension and progression of nephropathy in db/db mice. We observed that metformin- normalized systolic blood pressure in hypertensive diabetic mice. Mechanistically, metformin treatment reduced renal cathepsin B expression. Low cathepsin B expression was associated with reduced expression and activity of the epithelial sodium channel (ENaC), sodium retention, and thus control of hypertension. In addition, we identified that urinary extracellular vesicles (EVs) from the diabetic mice are enriched in cathepsin B. Compared to treatment with urinary EVs of vehicle-treated hypertensive diabetic mice, the amiloride-sensitive transepithelial current was significantly attenuated upon exposure of renal collecting duct cells to urinary EVs isolated from metformin-treated db/db mice or cathepsin B knockout mice. Collectively, our study identifies a novel blood pressure reducing role of metformin in diabetic nephropathy by regulating the cathepsin B-ENaC axis.

A reconstruction of parasite burden reveals one century of climate-associated parasite decline.

Long-term data allow ecologists to assess trajectories of population abundance. Without this context, it is impossible to know whether a taxon is thriving or declining to extinction. For parasites of wildlife, there are few long-term data-a gap that creates an impediment to managing parasite biodiversity and infectious threats in a changing world. We produced a century-scale time series of metazoan parasite abundance and used it to test whether parasitism is changing in Puget Sound, United States, and, if so, why. We performed parasitological dissection of fluid-preserved specimens held in natural history collections for eight fish species collected between 1880 and 2019. We found that parasite taxa using three or more obligately required host species-a group that comprised 52% of the parasite taxa we detected-declined in abundance at a rate of 10.9% per decade, whereas no change in abundance was detected for parasites using one or two obligately required host species. We tested several potential mechanisms for the decline in 3+-host parasites and found that parasite abundance was negatively correlated with sea surface temperature, diminishing at a rate of 38% for every 1 °C increase. Although the temperature effect was strong, it did not explain all variability in parasite burden, suggesting that other factors may also have contributed to the long-term declines we observed. These data document one century of climate-associated parasite decline in Puget Sound-a massive loss of biodiversity, undetected until now.