8 research outputs found
Interactions between respiratory oscillators in adult rats
Breathing in mammals is hypothesized to result from the interaction of two distinct oscillators: the preBötzinger Complex (preBötC) driving inspiration and the lateral parafacial region (pFL) driving active expiration. To understand the interactions between these oscillators, we independently altered their excitability in spontaneously breathing vagotomized urethane-anesthetized adult rats. Hyperpolarizing preBötC neurons decreased inspiratory activity and initiated active expiration, ultimately progressing to apnea, i.e., cessation of both inspiration and active expiration. Depolarizing pFL neurons produced active expiration at rest, but not when inspiratory activity was suppressed by hyperpolarizing preBötC neurons. We conclude that in anesthetized adult rats active expiration is driven by the pFL but requires an additional form of network excitation, i.e., ongoing rhythmic preBötC activity sufficient to drive inspiratory motor output or increased chemosensory drive. The organization of this coupled oscillator system, which is essential for life, may have implications for other neural networks that contain multiple rhythm/pattern generators
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Role of parafacial nuclei in control of breathing in adult rats.
Contiguous brain regions associated with a given behavior are increasingly being divided into subregions associated with distinct aspects of that behavior. Using recently developed neuronal hyperpolarizing technologies, we functionally dissect the parafacial region in the medulla, which contains key elements of the central pattern generator for breathing that are important in central CO2-chemoreception and for gating active expiration. By transfecting different populations of neighboring neurons with allatostatin or HM4D Gi/o-coupled receptors, we analyzed the effect of their hyperpolarization on respiration in spontaneously breathing vagotomized urethane-anesthetized rats. We identify two functionally separate parafacial nuclei: ventral (pFV) and lateral (pFL). Disinhibition of the pFL with bicuculline and strychnine led to active expiration. Hyperpolarizing pFL neurons had no effect on breathing at rest, or changes in inspiratory activity induced by hypoxia and hypercapnia; however, hyperpolarizing pFL neurons attenuated active expiration when it was induced by hypercapnia, hypoxia, or disinhibition of the pFL. In contrast, hyperpolarizing pFV neurons affected breathing at rest by decreasing inspiratory-related activity, attenuating the hypoxia- and hypercapnia-induced increase in inspiratory activity, and when present, reducing expiratory-related abdominal activity. Together with previous observations, we conclude that the pFV provides a generic excitatory drive to breathe, even at rest, whereas the pFL is a conditional oscillator quiet at rest that, when activated, e.g., during exercise, drives active expiration
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Kidney and Cardiovascular Effects of Canagliflozin According to Age and Sex:A Post Hoc Analysis of the CREDENCE Randomized Clinical Trial
Rationale & Objective: It is unclear whether the effect of canagliflozin on adverse kidney and cardiovascular events in those with diabetic kidney disease varies by age and sex. We assessed the effects of canagliflozin among age group categories and between sexes in the Canagliflozin and Renal Endpoints in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) study.Study Design: Secondary analysis of a randomized controlled trial.Setting & Participants: Participants in the CREDENCE trial.Intervention: Participants were randomly assigned to receive canagliflozin 100 mg/d or placebo.Outcomes: Primary composite outcome of kidney failure, doubling of serum creatinine concentration, or death due to kidney or cardiovascular disease. Prespecified secondary and safety outcomes were also analyzed. Outcomes were evaluated by age at baseline (<60, 60-69, and ≥70 years) and sex in the intention-to-treat population using Cox regression models.Results: The mean age of the cohort was 63.0 ± 9.2 years, and 34% were female. Older age and female sex were independently associated with a lower risk of the composite of adverse kidney outcomes. There was no evidence that the effect of canagliflozin on the primary outcome (a composite of kidney failure, a doubling of serum creatinine concentration, or death from kidney or cardiovascular causes) differed between age groups (HRs, 0.67 [95% CI, 0.52-0.87], 0.63 [0.48-0.82], and 0.89 [0.61-1.29] for ages <60, 60-69, and ≥70 years, respectively; P = 0.3 for interaction) or sexes (HRs, 0.71 [95% CI, 0.54-0.95] and 0.69 [0.56-0.84] in women and men, respectively; P = 0.8 for interaction). No differences in safety outcomes by age group or sex were observed.Limitations: This was a post hoc analysis with multiple comparisons.Conclusions: Canagliflozin consistently reduced the relative risk of kidney events in people with diabetic kidney disease in both sexes and across age subgroups. As a result of greater background risk, the absolute reduction in adverse kidney outcomes was greater in younger participants.Funding: This post hoc analysis of the CREDENCE trial was not funded. The CREDENCE study was sponsored by Janssen Research and Development and was conducted collaboratively by the sponsor, an academic-led steering committee, and an academic research organization, George Clinical.Trial Registration: The original CREDENCE trial was registered at ClinicalTrials.gov with study number NCT02065791.</p
Kidney and Cardiovascular Effects of Canagliflozin According to Age and Sex: A Post Hoc Analysis of the CREDENCE Randomized Clinical Trial
RATIONALE & OBJECTIVE: It is unclear whether the effect of canagliflozin on adverse kidney and cardiovascular events in those with diabetic kidney disease varies by age and sex. We assessed the effects of canagliflozin among age group categories and between sexes in the CREDENCE study. STUDY DESIGN: Secondary analysis of a randomized controlled trial. SETTING & PARTICIPANTS: Participants in the CREDENCE trial. INTERVENTION: Participants were randomly assigned to canagliflozin 100 mg daily or placebo. OUTCOMES: Primary composite outcome of kidney failure, doubling of serum creatinine, or death due to kidney or cardiovascular disease. Pre-specified secondary and safety outcomes were also analyzed. Outcomes were evaluated by age at baseline (<60, 60-69, and ≥70 years) and sex in the intention-to-treat population using Cox regression models. RESULTS: The mean age of the cohort was 63.0±9.2 years and 34% were female. Older age and female sex were independently associated with a lower risk of the composite of adverse kidney outcomes. There was no evidence that the effect of canagliflozin on the primary outcome (a composite of kidney failure, a doubling of the serum creatinine, or death from kidney or cardiovascular causes) differed between age groups (HR 0.67, 95% CI 0.52 to 0.87; HR 0.63, 95% CI 0.48 to 0.82; and HR 0.89, 95% CI 0.61 to 1.29; for the <60, 60-69, and ≥70 year groups, respectively; Pinteraction=0.3); or among females and males (HR 0.71, 95% CI 0.54 to 0.95; and HR 0.69, 95% CI 0.56 to 0.84, respectively; Pinteraction=0.8). No differences in safety outcomes by age group or sex were observed. LIMITATIONS: This was a post hoc analysis with multiple comparisons. CONCLUSIONS: Canagliflozin consistently reduced the relative risk of kidney events in people with diabetic kidney disease in both sexes and across age subgroups. Owing to higher background risk, the absolute reduction in adverse kidney outcomes was greater in younger participants
Kidney and Cardiovascular Effects of Canagliflozin According to Age and Sex: A Post Hoc Analysis of the CREDENCE Randomized Clinical Trial
Rationale & Objective: It is unclear whether the effect of canagliflozin on adverse kidney and cardiovascular events in those with diabetic kid-ney disease varies by age and sex. We assessed the effects of canagliflozin among age group categories and between sexes in the Canagli-flozin and Renal Endpoints in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) study.Study Design: Secondary analysis of a random-ized controlled trial. Setting & Participants: Participants in the CREDENCE trial. Intervention: Participants were randomly assigned to receive canagliflozin 100 mg/d or placebo.Outcomes: Primary composite outcome of kid-ney failure, doubling of serum creatinine con-centration, or death due to kidney or cardiovascular disease. Prespecified secondary and safety outcomes were also analyzed. Out-comes were evaluated by age at baseline (<60, 60-69, and >_70 years) and sex in the intention-to-treat population using Cox regression models.Results: The mean age of the cohort was 63.0 & PLUSMN; 9.2 years, and 34% were female. Older age and female sex were independently associ-ated with a lower risk of the composite of adverse kidney outcomes. There was no evidence that the effect of canagliflozin on the primary outcome (acomposite of kidney failure, a doubling of serum creatinine concentration, or death from kidney or cardiovascular causes) differed between age groups (HRs, 0.67 [95% CI, 0.52-0.87], 0.63 [0.4 8-0.82], and 0.89 [0.61-1.29] for ages <60, 60-69, and >_70 years, respectively; P = 0.3 for interaction) or sexes (HRs, 0.71 [95% CI, 0.5 4-0.95] and 0.69 [0.56-0.8 4] in women and men, respectively; P = 0.8 for interaction). No differences in safety outcomes by age group or sex were observed.Limitations: This was a post hoc analysis with multiple comparisons.Conclusions: Canagliflozin consistently reduced the relative risk of kidney events in people with diabetic kidney disease in both sexes and across age subgroups. As a result of greater background risk, the absolute reduction in adverse kidney outcomes was greater in younger participants.Funding: This post hoc analysis of the CREDENCE trial was not funded. The CREDENCE study was sponsored by Janssen Research and Development and was conducted collaboratively by the sponsor, an academic-led steering committee, and an academic research organization, George Clinical.Trial Registration: The original CREDENCE trial was registered at ClinicalTrials.gov with study number NCT02065791