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  • 1
    In: Scientific Reports, Springer Science and Business Media LLC, Vol. 10, No. 1 ( 2020-06-08)
    Abstract: Carotid bodies (CBs) are chemoreceptors that monitor and register changes in the blood, including the levels of oxygen, carbon dioxide, and pH, and regulate breathing. Enhanced activity of CBs was shown to correlate with a significant elevation in the blood pressure of patients with hypertension. CB removal or denervation were previously shown to reduce hypertension. Here we demonstrate the feasibility of a dual-mode ultrasound array (DMUA) system to safely ablate the CB in vivo in a spontaneously hypertensive rat (SHR) model of hypertension. DMUA imaging was used for guiding and monitoring focused ultrasound (FUS) energy delivered to the target region. In particular, 3D imaging was used to identify the carotid bifurcation for targeting the CBs. Intermittent, high frame rate imaging during image-guided FUS (IgFUS) delivery was used for monitoring the lesion formation. DMUA imaging provided feedback for closed-loop control (CLC) of the lesion formation process to avoid overexposure . The procedure was tolerated well in over 100 SHR and normotensive rats that received unilateral and bilateral treatments. The measured mean arterial pressure (MAP) exhibited measurable deviation from baseline 2–4 weeks post IgFUS treatment. The results suggest that the direct unilateral FUS treatment of the CB might be sufficient to reduce the blood pressure in hypertensive rats and justify further investigation in large animals and eventually in human patients.
    Type of Medium: Online Resource
    ISSN: 2045-2322
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2020
    detail.hit.zdb_id: 2615211-3
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  • 2
    In: Hypertension, Ovid Technologies (Wolters Kluwer Health), Vol. 68, No. suppl_1 ( 2016-09)
    Abstract: Cardiovascular disease (CVD) remains the most pervasive cause of death worldwide. High arterial pressure, or hypertension (HTN), is the highest risk factor for CVD morbidity and mortality. Increased peripheral and renal sympathetic nerve activity (SNA) is hypothesized to be a primary contributor to HTN etiology. Moreover, recent clinical and experimental studies show total renal denervation (T-RDNx), may reverse the HTN; however, the contribution of afferent and efferent renal nerves in this effect is unknown. We have recently reported T-RDNx and afferent-specific denervation (A-RDNx) identically attenuated the development of deoxycorticostereone acetate (DOCA)-salt hypertension. However, the efficacy of T-RDNx and A-RDNx to reverse the established phase of this model of HTN is unknown. Therefore, the present study tested the hypothesis that A-RDNx and T-RDNx would similarly decrease the mean arterial pressure (MAP) in DOCA-salt rats with established HTN. Twenty-four male Sprague Dawley rats (275-300g) instrumented with radiotelemeters were administered DOCA (100mg, s.c.) and 0.9% saline to drink ad libitum for 35 days. On day 21 of DOCA-salt, rats underwent T-RDNx (n=9), A-RDNx (n=9), or sham (n=6) treatments. MAP was monitored for an additional 14 days. Neurogenic pressor activity (NPA) was assessed 14 days after treatment by measuring the MAP response to acute ganglionic blockade (hexamethonium, 30mg/kg, i.p.). Data was analyzed with a one-way ANOVA with Bonferroni post-hoc test (α=0.05). Data presented as mean ± SEM. MAP was similar across all groups prior to treatment on Day 21 of DOCA-salt (Sham: 165±6; T-RDNx: 164±3; A-RDNx: 162±7mmHg). Whereas Sham had no effect (-2±3) on MAP 14 days after treatment, both RDNx treatments decreased MAP by approximately 20 mmHg (T-RDNx -18±8; A-RDNx -22±5). NPA 14 days after treatment in Sham rats was -97±12mmHg. This response was reduced by nearly half in both T-RDNx (-50±9mmHg) and A-RDNx (-48±4mmHg) groups. We conclude from these findings that: 1) RDNx is effective in treating the established phase of DOCA-salt hypertension, 2) the MAP response to RDNx is mediated by ablation of afferent renal nerves, and 3) the antihypertensive response to RDNx is mediated by a decrease global neurogenic pressor activity.
    Type of Medium: Online Resource
    ISSN: 0194-911X , 1524-4563
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2016
    detail.hit.zdb_id: 2094210-2
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  • 3
    In: Hypertension, Ovid Technologies (Wolters Kluwer Health), Vol. 64, No. suppl_1 ( 2014-09)
    Abstract: Renal denervation (RDNX) attenuates hypertension (HT) in some animal models and human patients, yet the antihypertensive mechanisms involved are not known. Because it has been suggested that efferent renal nerves may cause recruitment of T lymphocytes (T cells) into the kidneys, and T cell-secreted cytokines can activate afferent neurons, we hypothesized that RDNX attenuates HT in the angiotensin II (AngII)-salt and deoxycorticosterone acetate (DOCA)-salt models by decreasing efferent renal nerve-dependent T cell trafficking to the kidneys and T cell-mediated activation of afferent renal nerves. Male Sprague-Dawley rats underwent SHAM surgery, RDNX or selective ablation of afferent renal nerves (renal-CAP) and were subjected to either AngII-salt or DOCA-salt HT. AngII-salt rats underwent SHAM, RDNX or renal-CAP (n = 8/group) and were instrumented with an IV catheter and radio-telemeter to measure mean arterial pressure (MAP). Rats were fed a 4% NaCl diet and, after a baseline period, AngII was infused IV (10 ng/kg/min) for 16 days. DOCA-salt rats were unilaterally nephrectomized and, after 2 weeks, instrumented with a radio-telemeter, subjected to SHAM (n = 5), RDNX (n = 7) or renal-CAP (n = 6) and given 0.9% saline to drink. After a baseline period, silicone pellets containing 100mg DOCA were implanted SC and rats were sacrificed 3 weeks later. Upon sacrifice, kidneys were harvested for flow cytometry to determine the number of CD4+ and CD8+ T cells in the kidneys. In AngII-salt rats, renal CD4 and CD8 T cell counts and the change in MAP from baseline (ΔMAP) were similar between groups (SHAM = 42.3 ± 6.4 mmHg, RDNX = 32.6 ± 5.9 mmHg, renal-CAP = 36.8 ± 5.0 mmHg). In DOCA-salt rats, RDNX and renal-CAP significantly attenuated ΔMAP (SHAM = 24.2 ± 3.1 mmHg, RDNX = 12.7 ± 2.4 mmHg, renal-CAP = 13.8 ± 1.7 mmHg). CD8 T cell counts in RDNX kidneys were significantly lower than SHAM (p 〈 0.01) and trended lower than renal-CAP. CD4 T cell counts in RDNX kidneys were significantly lower than renal-CAP (p 〈 0.05) and trended lower than SHAM. These data show that renal nerves do not contribute to AngII-salt HT, but suggest that afferent renal nerves contribute to DOCA-salt HT and that this may be T cell-mediated and dependent on efferent renal nerves. Funding: R01 HL116476-01.
    Type of Medium: Online Resource
    ISSN: 0194-911X , 1524-4563
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2014
    detail.hit.zdb_id: 2094210-2
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  • 4
    In: Hypertension, Ovid Technologies (Wolters Kluwer Health), Vol. 79, No. Suppl_1 ( 2022-09)
    Abstract: Emerging evidence suggests an interaction between renal inflammation and afferent renal nerves in some preclinical models of hypertension. In this study we tested the hypothesis that the inflammatory cytokine IL-1β interacts with afferent renal nerves in the pathogenesis of the DOCA-salt mouse model of hypertension. Specifically, we compared the effect of total renal denervation (TRDN) and afferent RDN (ARDN) on the development of DOCA-salt hypertension to that observed in animals receiving the IL-1 receptor antagonist anakinra. In the first study , 10-week-old male C57BL6/J mice were implanted with radiotelemeters for measurement of mean arterial pressure (MAP). DOCA was administered via subcutaneous pellet containing 50 mg of DOCA, controls received a drug free pellet. Uni-nephrectomy, pellet insertion, salt treatment, TRDN, ARDN, or sham denervation were all performed on the same day. TRDN and ARDN was performed through peri-axonal application of phenol and capsaicin respectively. In the second study , the IL-1 receptor antagonist anakinra (75mg/kg) or vehicle control (0.9% saline) was delivered via intraperitoneal injection daily 10 days post-induction of hypertension. Renal cytokine protein was quantified by Multiplex ELISA. All values reported are mean + SEM, all groups n=5. In the first study , MAP increased in sham treated DOCA-salt mice +43 ± 1 mmHg from baseline by the end of the 3 rd week of DOCA-salt. This response was attenuated by 40% in TRDN (+26 ± 4 mmHg) and by 44% in ARDN DOCA-salt mice (+24 ± 3 mmHg). IL-1β was increased in DOCA-salt kidneys (2.1 ± 0.4 pg/mg) compared to control kidneys (0.36 ± 0.1 pg/mg). In the second study , anakinra similarly attenuated the increase in MAP by 45% (+21 ± 2 mmHg) compared to vehicle controls (+38 ± 1 mmHg). Neither ARDN nor IL-1 receptor antagonism had any effect on renal inflammatory cytokines IL-1β, IL-6, or TNFα. The comparable attenuation in the MAP response to DOCA-salt ARDN and anakinra treated groups as well as the unchanged inflammatory phenotype is consistent with a common mechanism of action. We hypothesize that intrarenal IL-1β activates sympathoexcitatory renal afferent nerves to increase MAP in DOCA-salt mice. Future studies are needed to directly test this hypothesis.
    Type of Medium: Online Resource
    ISSN: 0194-911X , 1524-4563
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2022
    detail.hit.zdb_id: 2094210-2
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  • 5
    In: The FASEB Journal, Wiley, Vol. 36, No. S1 ( 2022-05)
    Type of Medium: Online Resource
    ISSN: 0892-6638 , 1530-6860
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 1468876-1
    SSG: 12
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  • 6
    In: The FASEB Journal, Wiley, Vol. 34, No. S1 ( 2020-04), p. 1-1
    Type of Medium: Online Resource
    ISSN: 0892-6638 , 1530-6860
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 1468876-1
    SSG: 12
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  • 7
    Online Resource
    Online Resource
    American Physiological Society ; 2023
    In:  Physiology Vol. 38, No. S1 ( 2023-05)
    In: Physiology, American Physiological Society, Vol. 38, No. S1 ( 2023-05)
    Abstract: Clinical trials of renal denervation (RDN) have shown unanticipated changes in non-renal sympathetic activity. It has been hypothesized that this is due to ablation of sympathoexcitatory afferent renal nerves, which are overactive under conditions of renal inflammation. This study sought to investigate the interaction of the inflammatory cytokine, IL-1, and afferent renal nerves in the pathogenesis of hypertension. To test this hypothesis, we compared the effect of afferent RDN (ARDN) to the administration of the IL-1R antagonist anakinra, on the pathogenesis DOCA-salt hypertension. In addition, the combination of ARDN and anakinra treatments in DOCA-salt mice was administered to assess the degree of mechanistic overlap. 10-week-old male C57BL6/J mice were implanted with radio-telemetry probes in the carotid artery for measurement of mean arterial pressure (MAP). DOCA was administered via subcutaneous implantation of a silicon pellet containing 50 mg of DOCA. Sham mice received a drug free silicon pellet. Uni-nephrectomy, pellet insertion, salt treatment, ARDN were all performed or started on the same day. ARDN was performed through peri-axonal application of capsaicin. IL-1R antagonist anakinra was used to suppress activation of IL-1R. Anakinra (75mg/kg) was delivered via intraperitoneal injection daily 10 days post induction of hypertension. Animals in the untreated or monotherapy groups received sham RDN and/or vehicle injections. Baseline MAP was measured 3 days prior to induction of DOCA-salt hypertension by radiotelemetry. MAP increased in untreated DOCA-salt mice by 42 ± 2 mmHg (n=7) from baseline in the final week of the study. In comparison, this response was attenuated by 42% by ARDN (+24 ± 2 mmHg, n=7). IL-1α and IL-1β were both increased in DOCA-salt kidneys (112.4 ± 19.2 pg/mg and 2.1 ± 0.4 pg/mg respectively) compared to sham kidneys (31.98 ± 4.4 pg/mg and 0.36 ± 0.06 pg/mg respectively). The DOCA-salt induced increase of MAP in mice treated with anakinra alone (+23 ± 3 mmHg, n=9), or the combination of ARDN and anakinra (+26 ± 3 mmHg, n=5) was similar to ARDN monotherapy (+24 ± 2 mmHg, n=7). All treatment groups showed statistically significant changes in MAP compared to the SHAM and Vehicle treated group with 2 Way ANOVA and Tukey test for multiple comparisons. The finding that ARDN and anakinra combination therapy provides no additional benefit beyond ARDN or anakinra alone, suggests a common mechanism. We propose that antagonism of IL-1R blocks IL-1 mediated activation of afferent renal nerves resulting in decreased central sympathetic tone and decreased MAP. Further investigation into the mechanisms of cytokine mediated sensory fiber activation in the kidney are the subject of ongoing studies. T32DK083250-01A1, R01HL116476 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
    Type of Medium: Online Resource
    ISSN: 1548-9213 , 1548-9221
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2023
    detail.hit.zdb_id: 3115360-4
    detail.hit.zdb_id: 2005759-3
    SSG: 12
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  • 8
    In: The FASEB Journal, Wiley, Vol. 33, No. S1 ( 2019-04)
    Type of Medium: Online Resource
    ISSN: 0892-6638 , 1530-6860
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 1468876-1
    SSG: 12
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  • 9
    In: Development, The Company of Biologists, Vol. 141, No. 18 ( 2014-09-15), p. 3594-3604
    Abstract: In mammals, the meiotic cell cycle of oocytes starts during embryogenesis and then pauses. Much later, in preparation for fertilization, oocytes within preovulatory follicles resume meiosis in response to luteinizing hormone (LH). Before LH stimulation, the arrest is maintained by diffusion of cyclic (c)GMP into the oocyte from the surrounding granulosa cells, where it is produced by the guanylyl cyclase natriuretic peptide receptor 2 (NPR2). LH rapidly reduces the production of cGMP, but how this occurs is unknown. Here, using rat follicles, we show that within 10 min, LH signaling causes dephosphorylation and inactivation of NPR2 through a process that requires the activity of phosphoprotein phosphatase (PPP)-family members. The rapid dephosphorylation of NPR2 is accompanied by a rapid phosphorylation of the cGMP phosphodiesterase PDE5, an enzyme whose activity is increased upon phosphorylation. Later, levels of the NPR2 agonist C-type natriuretic peptide decrease in the follicle, and these sequential events contribute to the decrease in cGMP that causes meiosis to resume in the oocyte.
    Type of Medium: Online Resource
    ISSN: 1477-9129 , 0950-1991
    Language: English
    Publisher: The Company of Biologists
    Publication Date: 2014
    detail.hit.zdb_id: 2007916-3
    SSG: 12
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  • 10
    In: Physiology, American Physiological Society, Vol. 38, No. S1 ( 2023-05)
    Abstract: The risk of hypertension (HTN) in young females is lower than in young males, but this risk increases in postmenopausal females and surpasses that of age-matched males. The mechanisms by which fluctuating ovarian hormone environment during the menopause transition impacts the onset of HTN are poorly understood. Similarly, preventative and rehabilitative strategies to reduce HTN risk in peri- and postmenopausal females are lacking. Purpose: We aim to use an ovary-intact rat model of reproductive aging to accelerate the natural process of follicular loss and determine mechanisms contributing to the development of HTN in the Deoxycorticosterone (DOCA)-salt rat model. We hypothesize that induction of perimenopause by the chemical 4-vinylcyclohexene diepoxide (VCD) administration will increase the susceptibility to development of HTN in DOCA-salt rats. Methods: We repeated a daily dose of VCD for 15 days, which selectively destroys primordial and primary follicles in rodent ovaries to accelerate female rats into perimenopause. We then administered DOCA, in combination with a high-salt diet, to induce HTN in those rats. Female Sprague-Dawley rats at 28 post-natal day (pnd) were weighed and received subcutaneous injection of VCD (160mg/kg) for 15 consecutive days. Control rats were injected with a vehicle (corn oil; 2.5 mL/kg body weight). Under inhaled isoflurane anesthesia, 57 days after the first VCD/oil injection, uninephrectomy and telemetric pressure transducer (DSI) implantation were performed. After 2 weeks of recovery, a 100 mg/kg DOCA silicone or vehicle implant was placed subcutaneously. The animals were divided into oil+DOCA (N=3) and VCD (periestropause rats) +DOCA (N=6). DOCA-salt rats were provided 0.9% saline during the 21 days of DOCA protocol and mean arterial pressure (MAP) was continuously measured. Rats were housed weekly in metabolic cages for 24 hours to measure water intake and urine volume. At the end of the protocol the animals were anesthetized, and blood was collected into heparinized tubes for the measurement of anti-Mullerian hormone (AMH), estradiol (E2), and progesterone (P4) by ELISA. Results: The plasma concentrations of AMH were reduced in the periestropause animals compared to oil (VCD: ± 6.5 ng/mL; Oil: 19 ng/Ml; p= 0.0042) confirming the VCD-induced follicular depletion. The steady state increase in MAP (day 21 of DOCA-salt) was higher in periestropause (±45.7mmHg; p 〈 0.0001) compared to oil (±28.6 mmHg). No differences were observed in the saline intake between the groups. The urinary volume excretion was higher in periestropause rats (146.6 mL) compared to oil (112.6 mL). Conclusions: Our data suggest that periestropause rats showed greater susceptibility to the development of HTN in a DOCA-salt rat model. The possible mechanisms involved in this increased HTN risk are still being investigated through measurements of hormone concentrations of estradiol, progesterone, in addition to urinary cytokines and copeptin. NIH R01 HL116476 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
    Type of Medium: Online Resource
    ISSN: 1548-9213 , 1548-9221
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2023
    detail.hit.zdb_id: 3115360-4
    detail.hit.zdb_id: 2005759-3
    SSG: 12
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