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518. Comparable Outcomes of Remdesivir and Sotrovimab among High-risk Patients with Mild to Moderate COVID-19 During the Omicron BA.1 Surge
Chesdachai, Supavit , Teaford, Hiliary R, Larsen, Jennifer J., Tulledge‐Scheitel, Sidna M. , Chesdachai, Supavit , Rivera, Christina G. , Mara, Kristin C. , Teaford, Hiliary R, Suarez, Maria Lourdes Gonzalez , Ganesh, Ravindra , Razonable, Raymund R.

Mayo Clinic

Open Forum Infectious Diseases | November 27, 2023 | Volume: 10 | Issue: Supplement_2 | Pages: No page available

10.1093/ofid/ofad500.587 Get It

Abstract Background Two independent placebo-controlled clinical trials conducted prior to SARS-CoV-2 Omicron demonstrated that sotrovimab and remdesivir reduced hospitalization among high-risk outpatients with mild to moderate COVID-19. However, their effectiveness have not been directly compared. Methods This retrospective study examined all high-risk outpatients with mild to moderate COVID-19 who received either remdesivir or sotrovimab at Mayo Clinic during the Omicron BA.1 surge from January to March 2022. COVID-19-related hospitalization or death within 28 days were compared between the two treatment groups. Results Among 3,257 patients, 2,158 received sotrovimab and 1,099 received remdesivir. Patients treated with sotrovimab were younger (median age, 60 vs. 69 years) and had lower comorbidity (Monoclonal Antibody Screening Score, 5 vs. 6; Charlson Comorbidity Index, 3 vs. 4), but were more likely to be immunocompromised (47.3% vs. 30.2%) than remdesivir-treated patients. The majority (89%) had received at least one dose of COVID-19 vaccine (median, 3 doses [IQR 2-3] for both groups). COVID-19-related hospitalization (1.5% and 1.0% in remdesivir and sotrovimab groups, respectively, p=.15) and mortality within 28 days (0.4% in both groups, p=.82) were similarly low. A propensity score weighted analysis demonstrated no significant difference in the rates of COVID-related hospitalization and death within 28 days between the two groups. Conclusion This study demonstrated favorable outcomes that were not significantly different between patients treated with remdesivir or sotrovimab. As sotrovimab is no longer authorized, these results support the continued use of remdesivir for treating high-risk patients with COVID-19 during the current Omicron-predominant epoch. Disclosures Christina G. Rivera (O'Connor), Pharm.D, Gilead Sciences: Advisor/Consultant|Gilead Sciences: Board Member|Gilead Sciences: Grant/Research Support|Gilead Sciences: Honoraria Maria Gonzalez Suarez, M.D., Ph.D., Gilead: Grant/Research Support Ravindra Ganesh, M.B.B.S., M.D., Alpaca Health: Advisor/Consultant Raymund R. Razonable, MD, Allovir: Endpoint Adjudication Committee|American Society of Transplantation: Board Member|Gilead: Grant/Research Support|Novartis: DSMB|Regeneron: Grant/Research Support|Roche: Grant/Research Support
519. Early Transition to Outpatient Remdesivir Increases Patient Satisfaction while Decreasing Hospital Costs
Chesdachai, Supavit , Rosedahl, Jordan K., Dholakia, Ruchita, Draper, Evan , Arndt, Richard A., Larsen, Jennifer J., Borgen, Molly J. Destro, Chesdachai, Supavit , Rivera, Christina G. , Philpot, Lindsey M. , Borah, Bijan J. , Arndt, Richard, Ganesh, Ravindra , Razonable, Raymund R.

Mayo Clinic

Open Forum Infectious Diseases | November 27, 2023 | Volume: 10 | Issue: Supplement_2 | Pages: No page available

10.1093/ofid/ofad500.588 Get It

Abstract Background Remdesivir is FDA-approved for the treatment of hospitalized patients with severe COVID-19. Many patients improve clinically to allow for hospital dismissal before completing the 5-day course. In prior work, those who continued remdesivir in an outpatient setting had better outcomes. Here, we assessed patients’ perspectives and the economic impact of this outpatient practice. Methods During a one-year period, 3,029 patients received remdesivir for COVID-19 in the hospital; of them, 542 were dismissed to continue remdesivir in the outpatient setting and were surveyed. The cost of care was compared between those who remained in the hospital vs. those who were dismissed. Results 470 of 542 patients were surveyed, and 93 (19.8%) responded. Responders were older than non-responders (median, 63 vs. 58 years). The majority (70.5%) had symptoms resolved by the time of the survey. Ten patients (11.4%) had persistent symptoms attributed to long COVID-19, including fatigue (30.1%), brain fog (23.7%), and insomnia (18.3%). 73.8% were excited to learn about the outpatient remdesivir program. The majority (81.0%) felt that receiving therapy at home was the right decision; 79.5% had support and felt the benefits of completing treatment at home. The majority were satisfied with communication before (75.6%) and during (80.5%) the outpatient appointment, information on benefits (80.3%) and risks (58.5%), time spent at the infusion center (88.6%), quality of care (82.3%) and overall experience (76.0%). The benefits of treatment were high-value (82.6%), while the infusions' cost, inconvenience, and discomfort were unimportant for most responders. After adjusting for gender, comorbidity score, and WHO scale, the predicted costs for the groups were $16,544 (inpatient) and $9,097 (outpatient) per patient (difference of $7,447; p< .01). During this study, we estimated a total of 1,077 hospital room-days were made available to other patients. Conclusion An outpatient remdesivir program that allowed for early dismissal was perceived favorably by patients hospitalized for COVID-19. The program resulted in significant cost and resource savings, the latter in terms of the availability of hospital rooms for other patients needing critical services. Disclosures Christina G. Rivera (O'Connor), Pharm.D, Gilead Sciences: Advisor/Consultant|Gilead Sciences: Board Member|Gilead Sciences: Grant/Research Support|Gilead Sciences: Honoraria Bijan J. Borah, Ph.D., Boehringer Ingelheim: Advisor/Consultant|Exact Sciences: Advisor/Consultant Ravindra Ganesh, M.B.B.S., M.D., Alpaca Health: Advisor/Consultant Raymund R. Razonable, MD, Allovir: Endpoint Adjudication Committee|American Society of Transplantation: Board Member|Gilead: Grant/Research Support|Novartis: DSMB|Regeneron: Grant/Research Support|Roche: Grant/Research Support
1708. Molecular Epidemiology of Staphylococcus aureus Isolates Colonizing Infants in a Neonatal Intensive Care Unit: A 4-Year Cohort Study
Reis, Christopher, Siple, Leah M., Stetson, Raymond C. , Collura, Christopher A. , Fang, Jennifer L. , Gallup, Maria C. , Omdahl, Tami K, Daniels, Matthew L., Starkey, Jordan, Barth, Jean, Sampathkumar, Priya , Reis, Christopher , Siple, Leah, Chen, Jun , Patel, Robin , Huskins, W. Charles

Mayo Clinic

Open Forum Infectious Diseases | November 27, 2023 | Volume: 10 | Issue: Supplement_2 | Pages: No page available

10.1093/ofid/ofad500.1541 Get It

Abstract Background Staphylococcus aureus (SA) infections, both methicillin-susceptible and methicillin-resistant (MSSA, MRSA), cause significant morbidity among infants in neonatal intensive care units (NICU). Colonization usually precedes infection. We studied the molecular epidemiology of SA colonization in NICU infants using whole genome sequencing (WGS) and in relation to the opening of a new NICU with single-family rooms. Methods From 2019-22, a prospective cohort of infants admitted to the Level IV NICU at Mayo Clinic, Rochester, MN was screened twice weekly for SA colonization using cultures of nares/axilla/groin swabs. Infection control procedures were consistent throughout, including use of Contact Precautions for infants colonized with MRSA but not for MSSA. The study was divided into period 1 (1/1/2019-11/30/2020) and period 2 (12/1/2020-12/31/2022) due to a move from a 34-bed unit (26 beds in four open-bay rooms and 8 beds in single-family rooms) to a new 34-bed unit (all single-family rooms). WGS was performed using Illumina MiSeq instrumentation and chemistry with Illumina Nextera XT library chemistry. Assembly and core genome multilocus sequence typing analysis were performed with Ridom SeqSphere+ software. Groups of related isolates were identified based on the number of allelic differences (related 0-8 differences, possibly related 9-29 differences, unrelated ≥ 30 differences). Groups of MRSA-related isolates were compared with reference USA genotypes. Chi square tests did not adjust for clustering. Results There were 663 admissions in period 1 and 730 in period 2. The prevalence of MSSA and MRSA colonization was unchanged in the two periods (MSSA, 18.6% vs. 16.7%, p=0.37; MRSA 1.8% vs. 3.3%, p=0.08). By WGS, most MSSA and MRSA isolates were unrelated to another isolate in both periods (Table). Groups of related MSSA and MRSA isolates differed between the two periods and the number of isolates/group was small (< 6 isolates). Groups of related MRSA isolates were associated with reference genotypes USA100 (period 1), USA1000 (periods 1 & 2), and USA300 (period 2). WGS Results for MSSA and MRSA in Periods 1 and 2 Conclusion NICU infants were usually colonized with unrelated strains of MSSA and MRSA, with only small clusters of related strains. The new NICU was not associated with a change in MSSA or MRSA colonization. Disclosures Priya Sampathkumar, MD, Merck Vaccines: Advisor/Consultant Robin Patel, MD, Abbott Laboratories: Advisor/Consultant|Adaptive Phage Therapeutics: Grant/Research Support|Adaptive Phage Therapeutics: Mayo Clinic has a royalty-bearing know-how agreement and equity in Adaptive Phage Therapeutics.|BIOFIRE: Grant/Research Support|CARB-X: Advisor/Consultant|ContraFect: Grant/Research Support|Day Zero Diagnostics: Advisor/Consultant|HealthTrackRx: Advisor/Consultant|Mammoth Biosciences: Advisor/Consultant|Netflix: Advisor/Consultant|Oxford Nanopore Technologies: Advisor/Consultant|PhAST: Advisor/Consultant|See details: Patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic|See details: continued, patent on an anti-biofilm substance issued|TenNor Therapeutics Limited: Grant/Research Support|Torus Biosystems: Advisor/Consultant|Trellis Bioscience, Inc.: Advisor/Consultant W. Charles Huskins, MD, MSc, ADMA Biologics: Advisor/Consultant|Bristol Myers Squibb: Stocks/Bonds|Pfizer: Advisor/Consultant|Pfizer: Stocks/Bonds|Zimmer Biomet: Stocks/Bonds
Contribution of Adenosine to Skeletal Muscle Contraction‐Induced Vasodilation in Humans Is Not Increased with Age
Racine, Matthew L. , Richards, Jennifer C., Luckasen, Gary J. , Hearon, Christopher M. , Joyner, Michael J. , Dinenno, Frank A.

Mayo Clinic

The FASEB Journal | November 26, 2023 | Volume: 31 | Issue: S1 | Pages: No page available

10.1096/fasebj.31.1_supplement.840.13 Get It

Skeletal muscle blood flow during exercise is typically reduced in older compared with young adults, which may be mediated in part by age‐related reductions in local vasodilator molecules such as nitric oxide (NO) and ATP. Despite this, muscle blood flow does increase substantially to contracting muscle of older adults. We questioned whether reductions in muscle blood flow with age, particularly at the onset of exercise, leads to greater accumulation of local metabolites that could play a more prominent role in contraction‐induced vasodilation compared with young adults. Thus, in the present study we tested the hypothesis that the contribution of adenosine (ADO) to contraction‐induced vasodilation is greater in older vs. young adults. In young (25 ± 2 years; n=8) and older (65 ± 2 years; n=8) adults, forearm vascular conductance (FVC) responses to a single 20% maximum voluntary contraction (MVC) handgrip contraction and to 5 minutes of 10% MVC rhythmic handgrip exercise were measured using Doppler ultrasound of the brachial artery before and after brachial artery infusion of the ADO receptor blocker aminophylline (APH). In order to determine the effect of APH infusion that was due specifically to the blockade of ADO receptors as opposed to the elevated baseline FVC that often occurs as an off‐target effect of APH, FVC responses to contraction were also measured after sodium nitroprusside (SNP) infusion to match the APH‐induced increase in baseline FVC. In response to a single contraction, both total FVC area under the curve (AUC) and the absolute change in FVC from baseline to peak were lower in older vs. young adults (−61.2% and −56.1%, respectively; p < 0.05) under control conditions. There was no significant effect of APH on total FVC AUC in young (−5.4 ± 7.8%) or older (16.6 ± 12.4%) adults vs. control, whereas the absolute change in FVC from baseline to peak was significantly lower in young adults (−22.5 ± 7.7%; p < 0.05), but unaffected in older adults (4.1 ± 7.8%) vs. control. During rhythmic handgrip exercise, FVC was significantly lower in older adults in the first 60 sec of exercise (~45–50%) as well as during steady‐state (~25%; 110.0 ± 14.9 vs. 149.5 ±12.6 mL/min/100mmHg; both p < 0.05) under control conditions. APH had no effect on the FVC response throughout the first 3 min of exercise onset in young (range: 0.8–6.2%) or older (range: −3.9 to 10.5%) adults vs. control (p > 0.05), and did not alter the absolute change in FVC from baseline to steady‐state exercise in either group (p > 0.05). SNP had no effect on these FVC responses during single contractions or rhythmic handgrip exercise in either age group (p > 0.05). We conclude that that ADO contributes to the peak vasodilatory response to a single contraction in young but not older adults, and that advancing age is not associated with a greater reliance on ADO for local vasodilation during skeletal muscle contractions. Support or Funding Information HL095573, HL119337
Manipulating the Bone Marrow Microenvironment to Prevent Survival of AML Cells
Sterner, Rosalie M. , Dudakovic, Amel , Kremer, Kimberly N. , Westendorf, Jennifer J. , Wijnen, André J. van , Hedin, Karen E.

Mayo Clinic

The FASEB Journal | November 26, 2023 | Volume: 31 | Issue: S1 | Pages: No page available

10.1096/fasebj.31.1_supplement.775.3 Get It

The bone marrow microenvironment acts as a protective niche for malignant cells. Within the bone marrow microenvironment is the endosteal niche, which is the area where the ossified surface of the bone and marrow cavity interact. The endosteal niche provides the opportunity for hematological malignancies such as acute myeloid leukemia (AML) of the bone marrow to interact with osteoblasts from the bone. To study the interaction between AML cells and osteoblasts, our lab developed a co‐culture model of osteoblasts (MC3T3 osteoblast cell line) and AML cells (KG1a cell line or patient samples from bone marrow aspirates). AML cells expressing high levels of CXCR4 were cultured alone or with osteoblasts and then challenged with SDF‐1, the ligand to CXCR4 and a chemokine readily abundant in the bone marrow microenvironment that our lab has previously shown actually induces apoptosis in AML cells expressing high levels of CXCR4 and that osteoblasts are able to protect AML cells from SDF‐1 induced apoptosis. Our lab now shows that treating osteoblasts with cyclosporine (CSA) prevents their ability to effectively protect AML cells from SDF‐1 induced cell death as assayed by annexin‐V staining of AML cells by flow cytometry. CSA treatment of osteoblasts decreased protein levels of tissue non‐specific alkaline phosphatase (ALPL), a phosphatase necessary for osteoblast mineralization, compared to vehicle control. As such, osteoblasts were treated with control siRNA or ALPL siRNA. CXCR4 expressing AML cells were then co‐cultured with the transfected osteoblasts and challenged with SDF‐1. siRNA knockdown of ALPL in osteoblasts was sufficient to prevent protection of AML cells from the apoptotic stimuli. These studies indicate that osteoblast differentiation plays a role in mediating the protection of AML cells. Therefore, targeting specific differentiation factors in osteoblasts may help to make to bone marrow microenvironment a more hostile environment for AML cells and aid in better malignancy eradication. Support or Funding Information This study was supported by NIH R21 CA194217 (to K.E.H.). R.M.S. is supported by the Mayo Clinic Medical Scientist Training Program Robert L. Howell Physician‐Scientist Scholarship.
Comparing First‐Year Medical Students Performance on Radiology and Non‐Radiology Components of a Gross Anatomy Course
Knight, Jennifer , Stadem, Paul, Hoch, Wyatt B., Harvey, Jamison A. , Eiken, Patrick W. , Lachman, Nirusha , Pawlina, Wojciech, Ginsburg, Alexander , Gibbs, Christopher M.

Mayo Clinic

The FASEB Journal | November 26, 2023 | Volume: 31 | Issue: S1 | Pages: No page available

10.1096/fasebj.31.1_supplement.737.1 Get It

Radiology is often incorporated into medical school anatomy courses. Radiology education furthers understanding of anatomical relationships and prepares students to apply anatomical knowledge in clinical practice. The aim of this study was to investigate how cognitive performance on the radiology components (RC) of a first‐year medical school anatomy course are related to performance on non‐radiological components (NRC). We hypothesized that there is no correlation between these two performance variables, because they rely on different cognitive skills. Thus, anatomy education alone will not prepare students for the interpretation of normal anatomy on radiological images. Medical students (n=51) enrolled in a first‐year anatomy course at Mayo Clinic School of Medicine were included in this study. Assessment data from three lab practical examinations were collected, and RC and NRC questions were compared. A bivariate linear regression and statistical tests were conducted. A subgroup analysis was used to compare students whose RC performance was greater than their NRC performance (RC>NRC, n=33) to students whose RC performance was less than their NRC performance (RC<NRC, n=18). When considering all three exams, students correctly answered 71.1% of the RC questions and 68.3% of NRC questions (p=0.047). Bivariate linear regression demonstrated a moderate positive correlation between RC and NRC performance (p<0.01, r= 0.51); however, performance on RC questions only accounted for 24% of the variability of NRC scores. Additionally, students in the RC>NRC group had significantly higher scores on RC questions than the students in the RC<NRC group (74% vs 66%, p<0.02). Conversely, students in the RC>NRC group had significantly lower scores on NRC questions than the students in the RC<NRC group (61% vs 74%, p=0.001). These results indicate that while RC performance has some influence on NRC performance it does not account for the majority of the difference observed. Such results suggest that the cognitive skills involved in both radiology and anatomy education are different. Therefore, dedicated radiology education is an important component of an anatomy course as it fosters the development of novel skills that are necessary when interpreting normal anatomy on radiological images in a clinical setting. Support or Funding Information None
A Formal Interprofessional Ultrasound Curriculum between Medical and Physical Therapy Students in the First Year Gross Anatomy Course
Knight, Jennifer , Nuland, Sonya E. Van , Bhagra, Anjali , Gibbs, Christopher M. , Hellyer, Nathan J. , Langley, Natalie R.

Mayo Clinic

The FASEB Journal | November 26, 2023 | Volume: 31 | Issue: S1 | Pages: No page available

10.1096/fasebj.31.1_supplement.581.9 Get It

Ultrasound has been used more frequently in the anatomical sciences to reinforce core anatomy concepts in the classroom and introduce commonly applied imaging technologies encountered in a clinical setting. Interprofessional Education (IPE) is being incorporated into health sciences training as a learning model for real world interactions. The primary objective of the current study was to determine the impact of an IPE ultrasound curriculum on students' anatomy and ultrasound knowledge, as well as attitudes towards interprofessional collaboration. We hypothesized that students who participated in an IPE experience would have improved recall of anatomical and ultrasound concepts as well as improved attitudes and perceptions towards IPE when compared to students who did not participate in an IPE session. First year medical students (MD, n = 40) and first year physical therapy students (PT, n = 25) were randomly assigned to PT‐only, MD‐only, or mixed PT‐MD ultrasound instruction groups studying the shoulder. Students were assessed using an anatomy and ultrasound knowledge test and University of the West of England Interprofessional Questionnaire (UWEIPQ) prior to and following the session. The results of this study suggest that while ultrasound instruction significantly improves ultrasound post‐test scores when compared to pre‐test scores regardless of group assignment (PT‐only: p < 0.001; MD‐only: p = 0.007; PT‐MD: p < 0.001), learning in an interprofessional PT‐MD group did not significantly impact knowledge recall of ultrasound concepts when compared to non‐IPE groups. Interestingly, students in PT‐MD groups had significantly higher anatomy post‐test scores when compared to the MD‐only groups (PT‐MD post‐test = 93.2%; MD‐only post‐test = 84.1%; p = 0.041), but not when compared to the PT‐only groups. Additionally, the results of the UWEIPQ are consistent with the impression that students who participate in an IPE experience are more likely to be cognizant of inherent biases in the interactions between different health professionals as well as demonstrate increased confidence in their interprofessional relationships. In conclusion, our study reinforces that IPE programs should quantify knowledge recall in order to assess the effectiveness of a specific program. Furthermore, such endeavors should assess important competencies including communication, teamwork, and interdisciplinary respect that are necessary to succeed in a multidisciplinary health care team. Support or Funding Information Department of Anatomy, Mayo Clinic College of Medicine and Science, Mayo Clinic, Rochester, MN; Social Science and Humanities Research Council, Government of Canada
Mitochondrial Metabolic Dysregulation and Structural Abnormalities in a Rat Model of Polycystic Kidney Disease
Arroyo, Jennifer, Zhang, Song , Dzeja, Petras P. , Irazabal, María V. , Vučković, Ivan , Macura, Slobodan , Harris, Peter C. , Torres, Vicente E.

Mayo Clinic

The FASEB Journal | November 26, 2023 | Volume: 31 | Issue: S1 | Pages: No page available

10.1096/fasebj.31.1_supplement.1032.3 Get It

Background Autosomal Dominant Polycystic Kidney Disease (PKD) is the most frequent hereditary renal disease and the fourth leading cause of end‐stage renal disease. However, the exact mechanisms of cystogenesis and disease progression remain to be elucidated. Recent evidence suggests that a metabolic reprograming may underlie the dysregulation of several signaling pathways known to be affected in PKD. To identify the metabolic pathways associated with cystogenesis in the PKD kidney, we characterized the urinary, plasma, and tissue metabolome of PCK (a well established model of PKD) compared to Sprague‐Dawley (SD) wild‐type rats. Methods Male and female PCK and SD rats were treated with dDAVP (PCK‐D, n=16 or SD‐D, n=12) to aggravate the cystic phenotype and achieve animals with different degrees of disease severity for a given age, or saline solution (PCK‐S, n=16 or SD‐S, n=12) as controls. Total kidney volume (TKV) gold standard to assess disease severity, were measured by MRI, and urinary, plasma, and tissue metabolites by proton nuclear magnetic resonance, 1H‐NMR. Kidney metabolites identified from renal tissues collected at euthanasia were correlated with TKV. Mitochondrial structure was assessed by electron microscopy in proximal tubules (PT), medullary thick ascending limb (mTAL), distal tubules (DT), and collecting ducts (CD). Results Consistent with previously published data, administration of dDAVP significantly aggravated the disease in PCK rats (TKV) without inducing a cystic phenotype in SD rats (). Analysis of PCK and SD metabolomes by Partial least squares‐discriminant analysis (PLS‐DA) score plots showed a significant separation between the groups (). Integration of tissue, urine and plasma analysis revealed 5 metabolites (α‐ketoglutarate, fumarate, malate, citrate, and hippurate) consistently differentially expressed, among which 4 participate in the mitochondrial tricarboxylic acid (TCA) cycle (). Moreover, tissue TCA cycle metabolites correlated directly with TKV (). Mitochondrial area and matrix density were preserved in PT, mTAL, and DT of PCK rats, yet disruption of cristae membranes, swelling, and decreased matrix density were observed in their CD cystic cells (). Conclusions Comprehensive multilevel metabolomics analysis showed significant dysregulations of several mitochondrial TCA cycle metabolites in PCK rats, which further aggravated with the more severe phenotype. Notably, these changes were associated with mitochondrial structural abnormalities in the CD. Our observations suggest that mitochondrial damage and metabolic dysregulations may be implicated in cystogenesis, and position mitochondria as important therapeutic targets in PKD. Support or Funding Information This study was supported by the Mayo Translational Polycystic Kidney Disease Center (NIDDK P30 DK090728) and an endowment from Robert M. and Billie J. Pirnie for Kidney Research
ATP Maintains the Ability to Blunt α 1 ‐Adrenergic Vasoconstriction During Combined Blockade of Nitric Oxide, Prostaglandins, Na + /K
Richards, Jennifer C., Luckasen, Gary J. , Larson, Dennis G., Hearon, Christopher M. , Joyner, Michael J. , Dinenno, Frank A.

Mayo Clinic

The FASEB Journal | November 26, 2023 | Volume: 30 | Issue: S1 | Pages: No page available

10.1096/fasebj.30.1_supplement.752.4 Get It

The vasoactive properties of exogenous adenosine triphosphate (ATP) are unique because it has the dual ability to induce robust vasodilation as well as blunt sympathetic vasoconstriction, similar to what is observed in contracting human skeletal muscle. ATP‐mediated vasodilation and exercise hyperemia are dependent, in part, on activation of inwardly rectifying potassium (K IR ) channels and subsequent smooth muscle cell hyperpolarization, with a modest reliance on the production of nitric oxide (NO) and prostaglandins (PGs). However, recent studies from our laboratory indicate that these pathways are not obligatory for contracting skeletal muscle to blunt α 1 ‐adrenergic vasoconstriction. Given the specific role of K IR channels in ATP‐mediated vasodilation, the primary purpose of this study was to determine whether the ability of ATP to blunt α 1 ‐adrenergic vasoconstriction is dependent upon K IR channel activity in humans. A secondary purpose was to determine whether the ability of ATP to blunt α 1 ‐adrenergic vasoconstriction is dependent upon activation of K IR channels and Na + /K + ‐ATPase, as well as the synthesis of NO and PGs. In a total of 13 young subjects we measured forearm blood flow (Doppler ultrasound) and calculated changes in vascular conductance (FVC) to local intra‐arterial infusion of phenylephrine (PE; α 1 ‐agonist) during infusion of ATP or a control vasodilator(s) (Protocol 1 (n=7): adenosine (ADO), and sodium nitroprusside (SNP); Protocol 2 (n=6): ADO). Vasomotor responses were assessed before and after blockade of signaling pathways that contribute to ATP‐mediated vasodilation (Protocol 1: K IR channels (barium chloride); Protocol 2: combined blockade of K IR channels, Na + /K + ‐ATPase (ouabain), NO (L‐NMMA), PGs (Ketorolac)). Protocol 1: ATP significantly attenuated PE‐mediated vasoconstriction relative to both SNP and ADO (Δ FVC: ATP: −16 ± 2; ADO: −38 ± 6; SNP: −59 ± 6%; P<0.05 vs ADO and SNP). Blockade of K IR channels significantly attenuated ATP mediated vasodilation ~40% (P<0.05 vs. control), but had no effect on the ability of ATP to blunt PE‐ mediated vasoconstriction (Δ FVC: −6 ± 5%; P>0.05 vs. control). Protocol 2: Despite combined blockade of K IR , Na + /K + ‐ATPase, NO, and PGs resulting in profound attenuation of ATP‐mediated vasodilation (−~60%; P<0.01 vs. control), ATP was still able to blunt PE‐mediated vasoconstriction (Δ FVC: −4 ± 14%; P=0.50 vs. control). Together these studies highlight that while NO, PGs, and vascular smooth muscle hyperpolarization (via K IR channel activation) are contributors to the normal vasodilatory response to exercise and exogenous ATP, these pathways are not obligatory for exercise or ATP to blunt α 1 ‐adrenergic vasoconstriction in humans. Support or Funding Information Support: HL119337, HL095573
Amyloid and Tau PET Positivity in Progressive Agrammatic Aphasia and Apraxia of Speech
Pham, Nha Trang Thu, Lowe, Val J. , Josephs, Keith A. , Whitwell, Jennifer L. , Tetzloff, Katerina A. , Duffy, Joseph R. , Clark, Heather M. , Machulda, Mary M. , Botha, Hugo , Jack, Clifford R. , Dickson, Dennis W. , Utianski, Rene L.

Mayo Clinic

Journal of Alzheimer's Disease | November 21, 2023 | Volume: 96 | Issue: 4 | Pages: 1759-1765

10.3233/jad-230912 | PMID 38007664 Get It

Background: The agrammatic variant of primary progressive aphasia (PAA), primary progressive apraxia of speech (PPAOS), or a combination of both (AOS-PAA) are neurodegenerative disorders characterized by speech-language impairments and together compose the AOS-PAA spectrum disorders. These patients typically have an underlying 4-repeat tauopathy, although they sometimes show evidence of amyloid-β and tau deposition on PET, suggesting Alzheimer’s disease (AD). Given the growing number of pharmacologic treatment options for AD, it is important to better understand the incidence of AD pathology in these patients. Objective: This study aimed to evaluate the frequency of amyloid-β and tau positivity in AOS-PAA spectrum disorders. Sixty-five patients with AOS-PAA underwent a clinical speech-language battery and PiB PET and flortaucipir PET imaging. Methods: Global PiB PET standardized uptake value ratios (SUVRs) and flortaucipir PET SUVRs from the temporal meta region of interest were compared between patient groups. For 19 patients who had died and undergone autopsy, their PET and pathology findings were also compared. Results: The results showed that although roughly half of the patients are positive for at least one biomarker, their clinical symptoms and biomarker status were not related, suggesting that AD is not the primary cause of their neurodegeneration. All but one patient in the autopsy subset had a Braak stage of IV or less, despite four being positive on tau PET imaging. Conclusions: Inclusion criteria for clinical trials should specify clinical presentation or adjust the evaluation of such treatments to be specific to disease diagnosis beyond the presence of certain imaging biomarkers.