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McMillan NJ, Jacob DW, Shariffi B, Harper JL, Foster GE, Manrique-Acevedo C, Padilla J, Limberg JK. Effect of acute intranasal insulin administration on muscle sympathetic nerve activity in healthy young adults. Am J Physiol Heart Circ Physiol 2024; 327:H000. [PMID: 38787381 DOI: 10.1152/ajpheart.00253.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/14/2024] [Accepted: 05/23/2024] [Indexed: 05/25/2024]
Abstract
Systemic insulin increases muscle sympathetic nerve activity (MSNA) via both central actions within the brainstem and peripheral activation of the arterial baroreflex. Augmented MSNA during hyperinsulinemia likely restrains peripheral vasodilation and contributes to the maintenance of blood pressure (BP). However, in the absence of insulin action within the peripheral vasculature, whether central insulin stimulation increases MSNA and influences peripheral hemodynamics in humans remains unknown. Herein, we hypothesized intranasal insulin administration would increase MSNA and BP in healthy young adults. Participants were assigned to time control [TC, n = 13 (5 females/8 males), 28 ± 1 yr] or 160 IU of intranasal insulin administered over 5 min [n = 15 (5 females/10 males), 26 ± 2 yr]; five (1 female/4 males) participants completed both conditions. MSNA (fibular microneurography), BP (finger photoplethysmography), and leg blood flow (LBF, femoral Doppler ultrasound) were assessed at baseline, and 15 and 30 min following insulin administration. Leg vascular conductance [LVC = (LBF ÷ mean BP) × 100] was calculated. Venous insulin and glucose concentrations remained unchanged throughout (P > 0.05). Following intranasal insulin administration, MSNA (burst frequency; baseline = 100%; minute 15, 121 ± 8%; minute 30, 118 ± 6%; P = 0.009, n = 7) and mean BP (baseline = 100%; minute 15, 103 ± 1%; minute 30, 102 ± 1%; P = 0.003) increased, whereas LVC decreased (baseline = 100%; minute 15, 93 ± 3%; minute 30, 99 ± 3%; P = 0.03). In contrast, MSNA, mean BP, and LVC were unchanged in TC participants (P > 0.05). We provide the first evidence that intranasal insulin administration in healthy young adults acutely increases MSNA and BP and decreases LVC. These results enhance mechanistic understanding of the sympathetic and peripheral hemodynamic response to insulin.NEW & NOTEWORTHY Systemic insulin increases muscle sympathetic nerve activity (MSNA) via central actions within the brainstem and peripheral activation of the arterial baroreflex. In the absence of peripheral insulin action, whether central insulin stimulation increases MSNA and influences peripheral hemodynamics in humans was unknown. We provide the first evidence that intranasal insulin administration increases MSNA and blood pressure and reduces leg vascular conductance. These results enhance mechanistic understanding of the sympathetic and hemodynamic response to insulin.
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Affiliation(s)
- Neil J McMillan
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
- NextGen Precision Health, University of Missouri, Columbia, Missouri, United States
| | - Dain W Jacob
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
| | - Brian Shariffi
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
| | - Jennifer L Harper
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
| | - Glen E Foster
- School of Health and Exercise Sciences, Centre for Heart, Lung, and Vascular Health, University of British Columbia, Kelowna, Canada
| | - Camila Manrique-Acevedo
- NextGen Precision Health, University of Missouri, Columbia, Missouri, United States
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Missouri, Columbia, Missouri, United States
- Research Services, Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri, United States
| | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
- NextGen Precision Health, University of Missouri, Columbia, Missouri, United States
- Research Services, Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri, United States
| | - Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, United States
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Mannozzi J, Massoud L, Stavres J, Al-Hassan MH, O’Leary DS. Altered Autonomic Function in Metabolic Syndrome: Interactive Effects of Multiple Components. J Clin Med 2024; 13:895. [PMID: 38337589 PMCID: PMC10856260 DOI: 10.3390/jcm13030895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/12/2024] Open
Abstract
Metabolic syndrome (MetS) describes a set of disorders that collectively influence cardiovascular health, and includes hypertension, obesity, insulin resistance, diabetes, and dyslipidemia. All these components (hypertension, obesity, dyslipidemia, and prediabetes/diabetes) have been shown to modify autonomic function. The major autonomic dysfunction that has been documented with each of these components is in the control of sympathetic outflow to the heart and periphery at rest and during exercise through modulation of the arterial baroreflex and the muscle metaboreflex. Many studies have described MetS components in singularity or in combination with the other major components of metabolic syndrome. However, many studies lack the capability to study all the factors of metabolic syndrome in one model or have not focused on studying the effects of how each component as it arises influences overall autonomic function. The goal of this review is to describe the current understanding of major aspects of metabolic syndrome that most likely contribute to the consequent/associated autonomic alterations during exercise and discuss their effects, as well as bring light to alternative mechanisms of study.
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Affiliation(s)
- Joseph Mannozzi
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48001, USA
| | - Louis Massoud
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48001, USA
| | - Jon Stavres
- School of Kinesiology and Nutrition, University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | | | - Donal S. O’Leary
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48001, USA
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Shafiq MA, Ellingson CA, Krätzig GP, Dorsch KD, Neary JP, Singh J. Differences in Heart Rate Variability and Baroreflex Sensitivity between Male and Female Athletes. J Clin Med 2023; 12:3916. [PMID: 37373610 DOI: 10.3390/jcm12123916] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/01/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Heart rate variability (HRV), systolic blood pressure variability (BPV), and spontaneous baroreflex sensitivity (BRS) are indirect and approximate measures of autonomic regulation of the cardiovascular system. Studies have shown differences in HRV and BRS between males and females; however, no study has observed differences in BPV, HRV, or BRS between male and female athletes. One hundred males (age 21.2 ± 2.1 y; BMI 27.4 ± 4.5 kg/m2) and sixty-five females (age: 19.7 ± 1.6 y; BMI 22.7 ± 2.2 kg/m2) were assessed during the pre-season baseline. We collected resting beat-to-beat blood pressure and R-R intervals using finger photoplethysmography and a 3-lead electrocardiogram, respectively. Participants underwent a controlled slow breathing protocol (six breaths/minute: 5 s inhale, 5 s exhale) for 5 min. Spectral and linear analysis was conducted on blood pressure and ECG data. Regression curves were fitted to the blood pressure and R-R signals, with the slopes providing the BRS parameters. Male athletes had significantly (p < 0.05) lower mean heart rate, RR interval SD2/SD1, HRV % low-frequency, and higher BP high-frequency power during controlled respiration. No differences were found in any BRS parameters. HRV and BPV responses to a slow breathing protocol differed between male and female athletes; however, BRS responses did not.
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Affiliation(s)
- M Abdullah Shafiq
- Faculty of Kinesiology and Health Studies, University of Regina, 3737 Wascana Pkwy, Regina, SK S4S 0A2, Canada
| | - Cody A Ellingson
- Faculty of Kinesiology and Health Studies, University of Regina, 3737 Wascana Pkwy, Regina, SK S4S 0A2, Canada
| | - Gregory P Krätzig
- Department of Psychology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Kim D Dorsch
- Faculty of Kinesiology and Health Studies, University of Regina, 3737 Wascana Pkwy, Regina, SK S4S 0A2, Canada
| | - J Patrick Neary
- Faculty of Kinesiology and Health Studies, University of Regina, 3737 Wascana Pkwy, Regina, SK S4S 0A2, Canada
| | - Jyotpal Singh
- Faculty of Kinesiology and Health Studies, University of Regina, 3737 Wascana Pkwy, Regina, SK S4S 0A2, Canada
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Young BE, Padilla J, Shoemaker JK, Curry TB, Fadel PJ, Limberg JK. Sympathetic transduction to blood pressure during euglycemic-hyperinsulinemia in young healthy adults: role of burst amplitude. Am J Physiol Regul Integr Comp Physiol 2023; 324:R536-R546. [PMID: 36802950 PMCID: PMC10027119 DOI: 10.1152/ajpregu.00162.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 02/07/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023]
Abstract
Insulin acts centrally to stimulate sympathetic vasoconstrictor outflow to skeletal muscle and peripherally to promote vasodilation. Given these divergent actions, the "net effect" of insulin on the transduction of muscle sympathetic nerve activity (MSNA) into vasoconstriction and thus, blood pressure (BP) remains unclear. We hypothesized that sympathetic transduction to BP would be attenuated during hyperinsulinemia compared with baseline. In 22 young healthy adults, MSNA (microneurography), and beat-to-beat BP (Finometer or arterial catheter) were continuously recorded, and signal-averaging was performed to quantify the mean arterial pressure (MAP) and total vascular conductance (TVC; Modelflow) responses following spontaneous bursts of MSNA at baseline and during a euglycemic-hyperinsulinemic clamp. Hyperinsulinemia significantly increased MSNA burst frequency and mean burst amplitude (baseline: 46 ± 6 au; insulin: 65 ± 16 au, P < 0.001) but did not alter MAP. The peak MAP (baseline: 3.2 ± 1.5 mmHg; insulin: 3.0 ± 1.9 mmHg, P = 0.67) and nadir TVC (P = 0.45) responses following all MSNA bursts were not different between conditions indicating preserved sympathetic transduction. However, when MSNA bursts were segregated into quartiles based on their amplitudes at baseline and compared with similar amplitude bursts during hyperinsulinemia, the peak MAP and TVC responses were blunted (e.g., largest burst quartile: MAP, baseline: Δ4.4 ± 1.7 mmHg; hyperinsulinemia: Δ3.0 ± 0.8 mmHg, P = 0.02). Notably, ∼15% of bursts during hyperinsulinemia exceeded the size of any burst at baseline, yet the MAP/TVC responses to these larger bursts (MAP, Δ4.9 ± 1.4 mmHg) did not differ from the largest baseline bursts (P = 0.47). These findings indicate that increases in MSNA burst amplitude contribute to the overall maintenance of sympathetic transduction during hyperinsulinemia.
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Affiliation(s)
- Benjamin E Young
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas, United States
| | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, United States
| | | | - Timothy B Curry
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas, United States
| | - Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, United States
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, United States
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
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Manrique-Acevedo C, Soares RN, Smith JA, Park LK, Burr K, Ramirez-Perez FI, McMillan NJ, Ferreira-Santos L, Sharma N, Olver TD, Emter CA, Parks EJ, Limberg JK, Martinez-Lemus LA, Padilla J. Impact of sex and diet-induced weight loss on vascular insulin sensitivity in type 2 diabetes. Am J Physiol Regul Integr Comp Physiol 2023; 324:R293-R304. [PMID: 36622084 PMCID: PMC9942885 DOI: 10.1152/ajpregu.00249.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 12/02/2022] [Accepted: 12/26/2022] [Indexed: 01/10/2023]
Abstract
Vascular insulin resistance, a major characteristic of obesity and type 2 diabetes (T2D), manifests with blunting of insulin-induced vasodilation. Although there is evidence that females are more whole body insulin sensitive than males in the healthy state, whether sex differences exist in vascular insulin sensitivity is unclear. Also uncertain is whether weight loss can reestablish vascular insulin sensitivity in T2D. The purpose of this investigation was to 1) establish if sex differences in vasodilatory responses to insulin exist in absence of disease, 2) determine whether female sex affords protection against the development of vascular insulin resistance with long-term overnutrition and obesity, and 3) examine if diet-induced weight loss can restore vascular insulin sensitivity in men and women with T2D. First, we show in healthy mice and humans that sex does not influence insulin-induced femoral artery dilation and insulin-stimulated leg blood flow, respectively. Second, we provide evidence that female mice are protected against impairments in insulin-induced dilation caused by overnutrition-induced obesity. Third, we show that men and women exhibit comparable levels of vascular insulin resistance when T2D develops but that diet-induced weight loss is effective at improving insulin-stimulated leg blood flow, particularly in women. Finally, we provide indirect evidence that these beneficial effects of weight loss may be mediated by a reduction in endothelin-1. In aggregate, the present data indicate that female sex confers protection against obesity-induced vascular insulin resistance and provide supportive evidence that, in women with T2D, vascular insulin resistance can be remediated with diet-induced weight loss.
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Affiliation(s)
- Camila Manrique-Acevedo
- Division of Endocrinology and Metabolism, Department of Medicine, University of Missouri, Columbia, Missouri
- NextGen Precision Health, University of Missouri, Columbia, Missouri
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, Missouri
| | - Rogerio N Soares
- NextGen Precision Health, University of Missouri, Columbia, Missouri
| | - James A Smith
- NextGen Precision Health, University of Missouri, Columbia, Missouri
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Lauren K Park
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
- Division of Cardiology, Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri
| | - Katherine Burr
- NextGen Precision Health, University of Missouri, Columbia, Missouri
| | | | - Neil J McMillan
- NextGen Precision Health, University of Missouri, Columbia, Missouri
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | | | - Neekun Sharma
- NextGen Precision Health, University of Missouri, Columbia, Missouri
- Department of Medicine, Center for Precision Medicine, University of Missouri, Columbia, Missouri
| | - T Dylan Olver
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri
- Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Craig A Emter
- NextGen Precision Health, University of Missouri, Columbia, Missouri
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri
| | - Elizabeth J Parks
- NextGen Precision Health, University of Missouri, Columbia, Missouri
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Missouri, Columbia, Missouri
| | - Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Luis A Martinez-Lemus
- NextGen Precision Health, University of Missouri, Columbia, Missouri
- Department of Medicine, Center for Precision Medicine, University of Missouri, Columbia, Missouri
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Jaume Padilla
- NextGen Precision Health, University of Missouri, Columbia, Missouri
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, Missouri
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
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Limberg JK, Soares RN, Padilla J. Role of the Autonomic Nervous System in the Hemodynamic Response to Hyperinsulinemia-Implications for Obesity and Insulin Resistance. Curr Diab Rep 2022; 22:169-175. [PMID: 35247145 PMCID: PMC9012695 DOI: 10.1007/s11892-022-01456-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/30/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE OF REVIEW Herein, we summarize recent advances which provide new insights into the role of the autonomic nervous system in the control of blood flow and blood pressure during hyperinsulinemia. We also highlight remaining gaps in knowledge as it pertains to the translation of findings to relevant human chronic conditions such as obesity, insulin resistance, and type 2 diabetes. RECENT FINDINGS Our findings in insulin-sensitive adults show that increases in muscle sympathetic nerve activity with hyperinsulinemia do not result in greater sympathetically mediated vasoconstriction in the peripheral circulation. Both an attenuation of α-adrenergic-receptor vasoconstriction and augmented β-adrenergic vasodilation in the setting of high insulin likely explain these findings. In the absence of an increase in sympathetically mediated restraint of peripheral vasodilation during hyperinsulinemia, blood pressure is supported by increases in cardiac output in insulin-sensitive individuals. We highlight a dynamic interplay between central and peripheral mechanisms during hyperinsulinemia to increase sympathetic nervous system activity and maintain blood pressure in insulin-sensitive adults. Whether these results translate to the insulin-resistant condition and implications for long-term cardiovascular regulation warrants further exploration.
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Affiliation(s)
- Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, 204 Gwynn Hall, Columbia, MO, 65211, USA.
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA.
| | - Rogerio N Soares
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, 204 Gwynn Hall, Columbia, MO, 65211, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
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