Pentraxin 3 (PTX3), a cardioprotective protein, has recently been shown to be associated with imp... more Pentraxin 3 (PTX3), a cardioprotective protein, has recently been shown to be associated with improved insulin resistance (IR) and glucose metabolism. Therefore, the primary purpose of this study was to examine whether or not increased plasma PTX3 following maximal aerobic exercise would differ between obese and normal-mass subjects, and its association with the homeostatic model assessment of insulin resistance (HOMA-IR) and glucose response. Twenty-five untrained obese (n = 13 [6 males and 7 females]) and normal-mass (n = 12 [5 males and 7 females]) subjects performed an acute bout of maximal aerobic exercise to assess maximal oxygen consumption (VO 2max). At baseline, plasma PTX3 concentrations are decreased in obese compared with normal-mass subjects and are negatively associated with plasma insulin and HOMA-IR values. In response to maximal exercise, plasma PTX3 responses were similar in obese and normal-mass subjects while the intensity of plasma PTX3 response as indicated by area under the curve analysis (AUCi) was not associated with HOMA-IR or glucose AUCi. However, PTX3 AUCi was positively associated with cardiorespiratory fitness levels (relative VO 2max). These findings suggest that PTX3 could serve as a biomarker for both metabolic health, as well as a measurement to monitor the effectiveness of exercise interventions in obesity.
The objective of this study was to examine whether acute aerobic exercise-mediated calprotectin i... more The objective of this study was to examine whether acute aerobic exercise-mediated calprotectin in plasma would be associated with monocyte chemotactic protein-1 (MCP-1), myeloperoxidase (MPO), and interleukin-6 (IL-6) in healthy individuals. Eleven healthy participants, aged 18 to 30 years, were recruited to perform a 30-min bout of aerobic exercise at 75% maximal oxygen uptake. Acute aerobic exercise elicited a significant elevation across time in plasma calprotectin, MCP-1, MPO, and IL-6. Body mass index (BMI) was positively correlated with calprotectin area-under-the-curve with " respect to increase " (AUCi) and IL-6 AUCi. Furthermore, calprotectin AUCi was positively correlated with IL-6 AUCi and MPO AUCi, even after controlling for BMI. Although MPO AUCi was positively correlated with IL-6 AUCi, this relationship no longer existed after controlling for BMI. These results suggest that acute aerobic exercise could mediate innate immune response associated with calprotectin and its related leukocyte chemotactic and inflammatory mediators, especially in individuals with elevated BMI.
Chitinase 3-like 1 (CHI3L1) and intelectin 1 (ITLN-1) recognize microbial N-acetylglucosamine pol... more Chitinase 3-like 1 (CHI3L1) and intelectin 1 (ITLN-1) recognize microbial N-acetylglucosamine polymer and galactofuranosyl carbohydrates , respectively. Both lectins are highly abundant in plasma and seem to play pro-and anti-inflammatory roles, respectively, in obesity and inflammatory-related illnesses. The aim of this study was to examine whether plasma levels of these lectins in obese subjects are useful for monitoring inflammatory conditions immediately influenced by acute aerobic exercise. Plasma interleukin-6, a pro-inflammatory cytokine, was also examined. Twenty-two (11 obese and 11 normal-weight) healthy subjects, ages 18–30 years, were recruited to perform a 30 min bout of acute aerobic exercise at 75% VO 2max. We confirmed higher baseline levels of plasma CHI3L1, but lower ITLN-1, in obese subjects than in normal-weight subjects. The baseline levels of CHI3L1 were negatively correlated with cardiorespiratory fitness (relative VO 2max). However, when controlled for BMI, the relationship between baseline level of CHI3L1 and relative VO 2max was no longer observed. While acute aerobic exercise elicited an elevation in these parameters, we found a lower ITLN-1 response in obese subjects compared to normal-weight subjects. Our study clearly indicates that acute aerobic exercise elicits a pro-inflammatory response (e.g. CHI3L1) with a lower anti-inflammatory effect (e.g. ITLN-1) in obese individuals. Furthermore, these lectins could be predictors of outcome of exercise interventions in obesity-associated inflammation.
Keywords: Obesity; Exercise; Chitinase-3 Protein 1; Intelectin-1; Interleukin-6; Inflammation
Obesity is associated with enhanced inflammation and mental stress, but limited information has a... more Obesity is associated with enhanced inflammation and mental stress, but limited information has addressed the potential additive effect of psychological stress on obesity-associated inflammation. This study examined whether obese subjects would elicit a greater host immune response (IL-6 mRNA and cytokine) to lipopolysaccharide (LPS) in response to mental stress. Blood samples for LPS-stimulated IL-6 mRNA and cytokine were collected prior to and following mental stress. Results showed that obese subjects elicited a greater LPS-induced IL-6 along with its mRNA expression following mental stress compared to normal-weight subjects. Stress-induced IL-6 cytokine response to LPS was correlated with the baseline levels of plasma LPS binding protein (LBP) and leptin. These findings are consistent with the idea that endogenous inflammatory agents (e.g., LBP and leptin), often elevated with obesity, enhance inflammatory responses to psychological stress.
Keywords: Obesity; Psychological Stress; Leptin; Interleukin-6; Lipopolysaccharide-Binding Protein
Pentraxin 3 (PTX3) is an acute phase protein expressed in response to pro-inflammatory stimuli du... more Pentraxin 3 (PTX3) is an acute phase protein expressed in response to pro-inflammatory stimuli during atherosclerosis. However, recent findings suggest that PTX3 is a counter-regulatory protein which enhances the anti-inflammatory response. Objective: Therefore, the capacity of PTX3 to alter the inflammatory milieu following in vitro stimulation of PBMCs with the pro-inflammatory lipid, palmitate, was examined. Methods: PBMCs from 17 healthy male donors were isolated and cultured under four separate conditions; 200 lmol/L palmitate, a physiologically relevant concentration of PTX3, in combination (pal + PTX3), and an unstimulated time-course control. Results: Palmitate-induced production of the counter-regulatory protein PTX3 was positively associated with the production of the anti-inflammatory cytokine interleukin 10 (IL-10) following in vitro stimulation of human PBMCs. Furthermore, stimulation of PBMCs in vitro with 500 pg/mL PTX3 elicited a significantly greater increase in IL-10 production compared to the palmitate stimulated conditions. However, PTX3 stimulation did not result in the production of the pro-inflammatory cytokines IL-1b, IL-6, and tumor necrosis factor alpha, and when combined with palmitate, did not alter the pro-inflammatory milieu from PBMCs in this study. Conclusion: These findings provide evidence supporting the role of PTX3 as a mediator of the anti-inflammatory response in physiologically relevant conditions, and suggests that PTX3 counter regulates the development of atherosclerosis by enhancing the production of IL-10.
Pentraxin 3 (PTX3) has recently been linked to obesity-associated inflammation, serving as a card... more Pentraxin 3 (PTX3) has recently been linked to obesity-associated inflammation, serving as a cardioprotective modulator against cardiovascular disease (CVD). Aerobic exercise has been shown to enhance plasma PTX3 levels; however, the impact of obesity on PTX3 response to exercise remains unknown.
Brain-derived neurotrophic factor (BDNF) serves as a vital regulator of neuronal proliferation an... more Brain-derived neurotrophic factor (BDNF) serves as a vital regulator of neuronal proliferation and survival, and has been shown to regulate energy homeostasis, glucose metabolism and body weight maintenance. Elevated concentrations of plasma BDNF have been associated with obesity and type 2 diabetes mellitus. Acute aerobic exercise transiently increases circulating BDNF, potentially correcting obesity-related metabolic impairment. The present study aimed to compare acute aerobic exercise elicited BDNF responses in obese and normal-weight subjects. Furthermore, we aimed to investigate whether acute exercise-induced plasma BDNF elevations would be associated with improved indices of insulin resistance, as well as substrate utilization [carbohydrate oxidation (CHOoxi) and fat oxidation (FAToxi)]. Twenty-two healthy, untrained subjects [11 obese (four men and seven women; age = 22.91 AE 4.44 years; body mass index = 35.72 AE 4.17 kg/m 2 ) and 11 normal-weight (five men and six women; age = 23.27 AE 2.24 years; body mass index = 21.89 AE 1.63 kg/m 2 )] performed 30 min of continuous submaximal aerobic exercise at 75% maximal oxygen consumption. Our analyses showed that the BDNF response to acute aerobic exercise was similar in obese and normal-weight subjects across time (time: P = 0.015; group: P = not significant) and was not associated with indices of IR. Although no differences in the rates of CHOoxi and FAToxi were found between both groups, total relative energy expenditure was significantly lower in obese subjects compared to normal-weight subjects (3.53 AE 0.25 versus 5.59 AE 0.85; P < 0.001). These findings suggest that acute exerciseelicited BDNF elevation may not be sufficient to modulate indices of IR or the utilization of either carbohydrates or fats in obese individuals.
Vitamin D plays an essential role in the regulation of skeletal metabolism as well as calcium and... more Vitamin D plays an essential role in the regulation of skeletal metabolism as well as calcium and phosphate homeostasis, while vitamin D receptor (VDR) regulates de novo lipid synthesis, thereby contributing to the development of obesity. Furthermore, obese individuals are at a greater risk for vitamin D deficiency which may increase the potential risk for chronic inflammation, insulin resistance, and metabolic syndrome. While acute exercise enhances the activation of inflammatory signaling pathways, chronic exercise training may attenuate elevated proinflammatory cytokine production, resulting in the improvement of cardiovascular and metabolic health in obese individuals. Supplementation with vitamin D coupled with exercise or mild caloric restriction has been shown to improve markers of fitness and inflammation as well as cholesterol. Therefore, this review primarily addresses the impact of vitamin D deficiency in obesityrelated inflammatory imbalances and how exercise and weight-loss interventions may enhance the beneficial effects on vitamin D-mediated inflammation in obesity.
Background and aim: Fibroblast growth factor 21 (FGF21) is positively associated with body mass i... more Background and aim: Fibroblast growth factor 21 (FGF21) is positively associated with body mass index, potentially as a compensatory mechanism to mediate obesity related metabolic and inflammatory insult due to chronic low-grade elevations of the pro-inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-a). Therefore, FGF21 response in obese subjects and the associations with increased pro-inflammatory cytokines, insulin resistance, and energy utilization warrants investigation. Methods and results: Twenty four untrained subjects (12 obese and 12 normal-weight) performed 30 min of continuous submaximal aerobic exercise. Following exercise, obese subjects exhibited a blunted FGF21 response to exercise compared to normal-weight subjects as indicated by area-under-the-curves " with respect to increase " (AUCi) analyses (p Z 0.005). Furthermore, while exercise-induced plasma FGF21 was not associated with any inflammatory cytokine (IL-6 and TNF-a) response, FGF21 AUCi was positively correlated with glucose AUCi (r Z 0.495, p Z 0.014), total relative energy expenditure (r Z 0.562, p Z 0.004), and relative maximal oxygen consumption (VO 2max ; r Z 0.646, p Z 0.001) in all subjects. Conclusion: Impaired cardiorespiratory fitness may influence the sensitivity of FGF21 response to acute exercise in obese individuals, potentially contributing to the attenuated metabolic response (e.g., glucose) and total exercise energy expenditure. Therefore, exercise training aimed at improving cardiorespiratory fitness and/or body composition may augment cardioprotective properties against obesity-associated CVD through enhanced FGF21 flux.
Keywords: FGF21; Interleukin-6; Tumor necrosis factor-alpha; Energy Expenditure; Insulin Resistance
Aims: G protein-coupled receptor kinase 2 (GRK2), a cytosolic enzyme desensitizing G protein-coup... more Aims: G protein-coupled receptor kinase 2 (GRK2), a cytosolic enzyme desensitizing G protein-couple receptors (e.g., β-adrenergic receptors [β-ARs]), is involved in regulation of hypertension, congestive heart failure, and in-flammatory response. Since cellular GRK2 levels change quickly in response to exogenous/endogenous stimuli, this study examined whether GRK2 levels in human peripheral blood mononuclear cells (PBMCs) would increase during acute aerobic exercise and be associated with plasma IL-6 and cardiorespiratory fitness levels. Main methods: Eighteen subjects (8 men and 10 women), ages 18 to 30 years, were recruited to perform a 30-minute bout of acute aerobic exercise at 75% VO 2max. Key findings: Our results demonstrated that women exhibited significantly greater exercise-induced GRK2 expression in PBMCs compared to men. IL-6 modulation is independent of GRK2 expression. Furthermore, the percent change in GRK2 expression was negatively correlated with cardiorespiratory fitness levels (relative VO 2max), but not plasma IL-6. Significance: Acute aerobic exercise induces a greater GRK2 expression in women than men, while increased car-diorespiratory fitness is associated with exercise-induced GRK2 expression in PBMCs. Gender could be a contributor to regulate this GRK2 responsiveness to acute aerobic exercise.
ABSTRACT: Obesity-related oxidative stress, the imbalance between pro-oxidants and antioxidants (... more ABSTRACT: Obesity-related oxidative stress, the imbalance between pro-oxidants and antioxidants (e.g., nitric oxide), has been linked to metabolic and cardiovascular disease, including endothelial dysfunction and atherosclerosis. Reactive oxygen species (ROS) are essential for physiological functions including gene expression, cellular growth, infection defense, and modulating endothelial function. However, elevated ROS and/or diminished antioxidant capacity leading to oxidative stress can lead to dysfunction. Physical activity also results in an acute state of oxidative stress. However, it is likely that chronic physical activity provides a stimulus for favorable oxidative adaptations and enhanced physiological performance and physical health, although distinct responses between aerobic and anaerobic activities warrant further investigation. Studies support the benefits of dietary modification as well as exercise interventions in alleviating oxidative stress susceptibility. Since obese individuals tend to demonstrate elevated markers of oxidative stress, the implications for this population are significant. Therefore, in this review our aim is to discuss (i) the role of oxidative stress and inflammation as associated with obesity-related diseases, (ii) the potential concerns and benefits of exercise-mediated oxidative stress, and (iii) the advantageous role of dietary modification, including acute or chronic caloric restriction and vitamin D supplementation.
HIGHLIGHTS: 1. Acute exercise is a small source of oxidative stress while chronic exercise elicits protective adaptations against oxidative damage. 2. Chronic ingestion of energy-rich foods may contribute to obesity, while acute ingestion may also elicit potentially adverse metabolic responses including oxidative stress. 3. Caloric restriction may attenuate oxidative stress and serve as a beneficial weight loss intervention for obese individuals.
ABSTRACT Obesity is associated with an increased risk in neurodegenerative diseases. To counterac... more ABSTRACT Obesity is associated with an increased risk in neurodegenerative diseases. To counteract the neuronal damage, the human body increases brain-derived neurotrophic factor (BDNF) expression, leading to neuronal survival and plasticity. Recently, peripheral blood mononuclear cells (PBMCs) have been found to release BDNF as a potential neuroprotective role of inflammation. Therefore, the purpose of this study was to examine whether lipopolysaccharide (LPS)-induced PBMC activation would lead to differences in BDNF and inflammatory responses between obese and non-obese subjects. Thirty-one subjects (14 obese and 17 non-obese), ages 18 to 30 years, were recruited. PBMCs were cultured for 24 h with 10 ng/mL LPS. BDNF, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were measured in both plasma and cell culture supernatants. Our results did not illustrate any differences in plasma BDNF levels between obese and non-obese groups. However, obese subjects elicited a greater plasma IL-6 production, which was positively associated with plasma BDNF. Furthermore, LPS-induced PBMCs expressed significantly higher BDNF and IL-6 levels in obese subjects compared to the non-obese subjects. Finally, these BDNF levels were positively correlated with IL-6 response ex vivo. These findings suggest that under a high inflammatory state, PBMCs produce greater BDNF and IL-6 expression which may play a collaborative role to protect against neuronal damage associated with obesity.
HIGHLIGHTS • PBMCs from obese individuals elicited greater LPS-induced BDNF and IL-6 levels ex vivo. • LPS-activated human PBMCs showed a BDNF and IL-6 associative response. • BDNF and IL-6 may work together to lead to the neuroprotective effect in obesity.
Pentraxin 3 (PTX3), a cardioprotective protein, has recently been shown to be associated with imp... more Pentraxin 3 (PTX3), a cardioprotective protein, has recently been shown to be associated with improved insulin resistance (IR) and glucose metabolism. Therefore, the primary purpose of this study was to examine whether or not increased plasma PTX3 following maximal aerobic exercise would differ between obese and normal-mass subjects, and its association with the homeostatic model assessment of insulin resistance (HOMA-IR) and glucose response. Twenty-five untrained obese (n = 13 [6 males and 7 females]) and normal-mass (n = 12 [5 males and 7 females]) subjects performed an acute bout of maximal aerobic exercise to assess maximal oxygen consumption (VO 2max). At baseline, plasma PTX3 concentrations are decreased in obese compared with normal-mass subjects and are negatively associated with plasma insulin and HOMA-IR values. In response to maximal exercise, plasma PTX3 responses were similar in obese and normal-mass subjects while the intensity of plasma PTX3 response as indicated by area under the curve analysis (AUCi) was not associated with HOMA-IR or glucose AUCi. However, PTX3 AUCi was positively associated with cardiorespiratory fitness levels (relative VO 2max). These findings suggest that PTX3 could serve as a biomarker for both metabolic health, as well as a measurement to monitor the effectiveness of exercise interventions in obesity.
The objective of this study was to examine whether acute aerobic exercise-mediated calprotectin i... more The objective of this study was to examine whether acute aerobic exercise-mediated calprotectin in plasma would be associated with monocyte chemotactic protein-1 (MCP-1), myeloperoxidase (MPO), and interleukin-6 (IL-6) in healthy individuals. Eleven healthy participants, aged 18 to 30 years, were recruited to perform a 30-min bout of aerobic exercise at 75% maximal oxygen uptake. Acute aerobic exercise elicited a significant elevation across time in plasma calprotectin, MCP-1, MPO, and IL-6. Body mass index (BMI) was positively correlated with calprotectin area-under-the-curve with " respect to increase " (AUCi) and IL-6 AUCi. Furthermore, calprotectin AUCi was positively correlated with IL-6 AUCi and MPO AUCi, even after controlling for BMI. Although MPO AUCi was positively correlated with IL-6 AUCi, this relationship no longer existed after controlling for BMI. These results suggest that acute aerobic exercise could mediate innate immune response associated with calprotectin and its related leukocyte chemotactic and inflammatory mediators, especially in individuals with elevated BMI.
Chitinase 3-like 1 (CHI3L1) and intelectin 1 (ITLN-1) recognize microbial N-acetylglucosamine pol... more Chitinase 3-like 1 (CHI3L1) and intelectin 1 (ITLN-1) recognize microbial N-acetylglucosamine polymer and galactofuranosyl carbohydrates , respectively. Both lectins are highly abundant in plasma and seem to play pro-and anti-inflammatory roles, respectively, in obesity and inflammatory-related illnesses. The aim of this study was to examine whether plasma levels of these lectins in obese subjects are useful for monitoring inflammatory conditions immediately influenced by acute aerobic exercise. Plasma interleukin-6, a pro-inflammatory cytokine, was also examined. Twenty-two (11 obese and 11 normal-weight) healthy subjects, ages 18–30 years, were recruited to perform a 30 min bout of acute aerobic exercise at 75% VO 2max. We confirmed higher baseline levels of plasma CHI3L1, but lower ITLN-1, in obese subjects than in normal-weight subjects. The baseline levels of CHI3L1 were negatively correlated with cardiorespiratory fitness (relative VO 2max). However, when controlled for BMI, the relationship between baseline level of CHI3L1 and relative VO 2max was no longer observed. While acute aerobic exercise elicited an elevation in these parameters, we found a lower ITLN-1 response in obese subjects compared to normal-weight subjects. Our study clearly indicates that acute aerobic exercise elicits a pro-inflammatory response (e.g. CHI3L1) with a lower anti-inflammatory effect (e.g. ITLN-1) in obese individuals. Furthermore, these lectins could be predictors of outcome of exercise interventions in obesity-associated inflammation.
Keywords: Obesity; Exercise; Chitinase-3 Protein 1; Intelectin-1; Interleukin-6; Inflammation
Obesity is associated with enhanced inflammation and mental stress, but limited information has a... more Obesity is associated with enhanced inflammation and mental stress, but limited information has addressed the potential additive effect of psychological stress on obesity-associated inflammation. This study examined whether obese subjects would elicit a greater host immune response (IL-6 mRNA and cytokine) to lipopolysaccharide (LPS) in response to mental stress. Blood samples for LPS-stimulated IL-6 mRNA and cytokine were collected prior to and following mental stress. Results showed that obese subjects elicited a greater LPS-induced IL-6 along with its mRNA expression following mental stress compared to normal-weight subjects. Stress-induced IL-6 cytokine response to LPS was correlated with the baseline levels of plasma LPS binding protein (LBP) and leptin. These findings are consistent with the idea that endogenous inflammatory agents (e.g., LBP and leptin), often elevated with obesity, enhance inflammatory responses to psychological stress.
Keywords: Obesity; Psychological Stress; Leptin; Interleukin-6; Lipopolysaccharide-Binding Protein
Pentraxin 3 (PTX3) is an acute phase protein expressed in response to pro-inflammatory stimuli du... more Pentraxin 3 (PTX3) is an acute phase protein expressed in response to pro-inflammatory stimuli during atherosclerosis. However, recent findings suggest that PTX3 is a counter-regulatory protein which enhances the anti-inflammatory response. Objective: Therefore, the capacity of PTX3 to alter the inflammatory milieu following in vitro stimulation of PBMCs with the pro-inflammatory lipid, palmitate, was examined. Methods: PBMCs from 17 healthy male donors were isolated and cultured under four separate conditions; 200 lmol/L palmitate, a physiologically relevant concentration of PTX3, in combination (pal + PTX3), and an unstimulated time-course control. Results: Palmitate-induced production of the counter-regulatory protein PTX3 was positively associated with the production of the anti-inflammatory cytokine interleukin 10 (IL-10) following in vitro stimulation of human PBMCs. Furthermore, stimulation of PBMCs in vitro with 500 pg/mL PTX3 elicited a significantly greater increase in IL-10 production compared to the palmitate stimulated conditions. However, PTX3 stimulation did not result in the production of the pro-inflammatory cytokines IL-1b, IL-6, and tumor necrosis factor alpha, and when combined with palmitate, did not alter the pro-inflammatory milieu from PBMCs in this study. Conclusion: These findings provide evidence supporting the role of PTX3 as a mediator of the anti-inflammatory response in physiologically relevant conditions, and suggests that PTX3 counter regulates the development of atherosclerosis by enhancing the production of IL-10.
Pentraxin 3 (PTX3) has recently been linked to obesity-associated inflammation, serving as a card... more Pentraxin 3 (PTX3) has recently been linked to obesity-associated inflammation, serving as a cardioprotective modulator against cardiovascular disease (CVD). Aerobic exercise has been shown to enhance plasma PTX3 levels; however, the impact of obesity on PTX3 response to exercise remains unknown.
Brain-derived neurotrophic factor (BDNF) serves as a vital regulator of neuronal proliferation an... more Brain-derived neurotrophic factor (BDNF) serves as a vital regulator of neuronal proliferation and survival, and has been shown to regulate energy homeostasis, glucose metabolism and body weight maintenance. Elevated concentrations of plasma BDNF have been associated with obesity and type 2 diabetes mellitus. Acute aerobic exercise transiently increases circulating BDNF, potentially correcting obesity-related metabolic impairment. The present study aimed to compare acute aerobic exercise elicited BDNF responses in obese and normal-weight subjects. Furthermore, we aimed to investigate whether acute exercise-induced plasma BDNF elevations would be associated with improved indices of insulin resistance, as well as substrate utilization [carbohydrate oxidation (CHOoxi) and fat oxidation (FAToxi)]. Twenty-two healthy, untrained subjects [11 obese (four men and seven women; age = 22.91 AE 4.44 years; body mass index = 35.72 AE 4.17 kg/m 2 ) and 11 normal-weight (five men and six women; age = 23.27 AE 2.24 years; body mass index = 21.89 AE 1.63 kg/m 2 )] performed 30 min of continuous submaximal aerobic exercise at 75% maximal oxygen consumption. Our analyses showed that the BDNF response to acute aerobic exercise was similar in obese and normal-weight subjects across time (time: P = 0.015; group: P = not significant) and was not associated with indices of IR. Although no differences in the rates of CHOoxi and FAToxi were found between both groups, total relative energy expenditure was significantly lower in obese subjects compared to normal-weight subjects (3.53 AE 0.25 versus 5.59 AE 0.85; P < 0.001). These findings suggest that acute exerciseelicited BDNF elevation may not be sufficient to modulate indices of IR or the utilization of either carbohydrates or fats in obese individuals.
Vitamin D plays an essential role in the regulation of skeletal metabolism as well as calcium and... more Vitamin D plays an essential role in the regulation of skeletal metabolism as well as calcium and phosphate homeostasis, while vitamin D receptor (VDR) regulates de novo lipid synthesis, thereby contributing to the development of obesity. Furthermore, obese individuals are at a greater risk for vitamin D deficiency which may increase the potential risk for chronic inflammation, insulin resistance, and metabolic syndrome. While acute exercise enhances the activation of inflammatory signaling pathways, chronic exercise training may attenuate elevated proinflammatory cytokine production, resulting in the improvement of cardiovascular and metabolic health in obese individuals. Supplementation with vitamin D coupled with exercise or mild caloric restriction has been shown to improve markers of fitness and inflammation as well as cholesterol. Therefore, this review primarily addresses the impact of vitamin D deficiency in obesityrelated inflammatory imbalances and how exercise and weight-loss interventions may enhance the beneficial effects on vitamin D-mediated inflammation in obesity.
Background and aim: Fibroblast growth factor 21 (FGF21) is positively associated with body mass i... more Background and aim: Fibroblast growth factor 21 (FGF21) is positively associated with body mass index, potentially as a compensatory mechanism to mediate obesity related metabolic and inflammatory insult due to chronic low-grade elevations of the pro-inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-a). Therefore, FGF21 response in obese subjects and the associations with increased pro-inflammatory cytokines, insulin resistance, and energy utilization warrants investigation. Methods and results: Twenty four untrained subjects (12 obese and 12 normal-weight) performed 30 min of continuous submaximal aerobic exercise. Following exercise, obese subjects exhibited a blunted FGF21 response to exercise compared to normal-weight subjects as indicated by area-under-the-curves " with respect to increase " (AUCi) analyses (p Z 0.005). Furthermore, while exercise-induced plasma FGF21 was not associated with any inflammatory cytokine (IL-6 and TNF-a) response, FGF21 AUCi was positively correlated with glucose AUCi (r Z 0.495, p Z 0.014), total relative energy expenditure (r Z 0.562, p Z 0.004), and relative maximal oxygen consumption (VO 2max ; r Z 0.646, p Z 0.001) in all subjects. Conclusion: Impaired cardiorespiratory fitness may influence the sensitivity of FGF21 response to acute exercise in obese individuals, potentially contributing to the attenuated metabolic response (e.g., glucose) and total exercise energy expenditure. Therefore, exercise training aimed at improving cardiorespiratory fitness and/or body composition may augment cardioprotective properties against obesity-associated CVD through enhanced FGF21 flux.
Keywords: FGF21; Interleukin-6; Tumor necrosis factor-alpha; Energy Expenditure; Insulin Resistance
Aims: G protein-coupled receptor kinase 2 (GRK2), a cytosolic enzyme desensitizing G protein-coup... more Aims: G protein-coupled receptor kinase 2 (GRK2), a cytosolic enzyme desensitizing G protein-couple receptors (e.g., β-adrenergic receptors [β-ARs]), is involved in regulation of hypertension, congestive heart failure, and in-flammatory response. Since cellular GRK2 levels change quickly in response to exogenous/endogenous stimuli, this study examined whether GRK2 levels in human peripheral blood mononuclear cells (PBMCs) would increase during acute aerobic exercise and be associated with plasma IL-6 and cardiorespiratory fitness levels. Main methods: Eighteen subjects (8 men and 10 women), ages 18 to 30 years, were recruited to perform a 30-minute bout of acute aerobic exercise at 75% VO 2max. Key findings: Our results demonstrated that women exhibited significantly greater exercise-induced GRK2 expression in PBMCs compared to men. IL-6 modulation is independent of GRK2 expression. Furthermore, the percent change in GRK2 expression was negatively correlated with cardiorespiratory fitness levels (relative VO 2max), but not plasma IL-6. Significance: Acute aerobic exercise induces a greater GRK2 expression in women than men, while increased car-diorespiratory fitness is associated with exercise-induced GRK2 expression in PBMCs. Gender could be a contributor to regulate this GRK2 responsiveness to acute aerobic exercise.
ABSTRACT: Obesity-related oxidative stress, the imbalance between pro-oxidants and antioxidants (... more ABSTRACT: Obesity-related oxidative stress, the imbalance between pro-oxidants and antioxidants (e.g., nitric oxide), has been linked to metabolic and cardiovascular disease, including endothelial dysfunction and atherosclerosis. Reactive oxygen species (ROS) are essential for physiological functions including gene expression, cellular growth, infection defense, and modulating endothelial function. However, elevated ROS and/or diminished antioxidant capacity leading to oxidative stress can lead to dysfunction. Physical activity also results in an acute state of oxidative stress. However, it is likely that chronic physical activity provides a stimulus for favorable oxidative adaptations and enhanced physiological performance and physical health, although distinct responses between aerobic and anaerobic activities warrant further investigation. Studies support the benefits of dietary modification as well as exercise interventions in alleviating oxidative stress susceptibility. Since obese individuals tend to demonstrate elevated markers of oxidative stress, the implications for this population are significant. Therefore, in this review our aim is to discuss (i) the role of oxidative stress and inflammation as associated with obesity-related diseases, (ii) the potential concerns and benefits of exercise-mediated oxidative stress, and (iii) the advantageous role of dietary modification, including acute or chronic caloric restriction and vitamin D supplementation.
HIGHLIGHTS: 1. Acute exercise is a small source of oxidative stress while chronic exercise elicits protective adaptations against oxidative damage. 2. Chronic ingestion of energy-rich foods may contribute to obesity, while acute ingestion may also elicit potentially adverse metabolic responses including oxidative stress. 3. Caloric restriction may attenuate oxidative stress and serve as a beneficial weight loss intervention for obese individuals.
ABSTRACT Obesity is associated with an increased risk in neurodegenerative diseases. To counterac... more ABSTRACT Obesity is associated with an increased risk in neurodegenerative diseases. To counteract the neuronal damage, the human body increases brain-derived neurotrophic factor (BDNF) expression, leading to neuronal survival and plasticity. Recently, peripheral blood mononuclear cells (PBMCs) have been found to release BDNF as a potential neuroprotective role of inflammation. Therefore, the purpose of this study was to examine whether lipopolysaccharide (LPS)-induced PBMC activation would lead to differences in BDNF and inflammatory responses between obese and non-obese subjects. Thirty-one subjects (14 obese and 17 non-obese), ages 18 to 30 years, were recruited. PBMCs were cultured for 24 h with 10 ng/mL LPS. BDNF, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were measured in both plasma and cell culture supernatants. Our results did not illustrate any differences in plasma BDNF levels between obese and non-obese groups. However, obese subjects elicited a greater plasma IL-6 production, which was positively associated with plasma BDNF. Furthermore, LPS-induced PBMCs expressed significantly higher BDNF and IL-6 levels in obese subjects compared to the non-obese subjects. Finally, these BDNF levels were positively correlated with IL-6 response ex vivo. These findings suggest that under a high inflammatory state, PBMCs produce greater BDNF and IL-6 expression which may play a collaborative role to protect against neuronal damage associated with obesity.
HIGHLIGHTS • PBMCs from obese individuals elicited greater LPS-induced BDNF and IL-6 levels ex vivo. • LPS-activated human PBMCs showed a BDNF and IL-6 associative response. • BDNF and IL-6 may work together to lead to the neuroprotective effect in obesity.
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Papers by Aaron Slusher
Keywords: Pentraxin 3; Obesity; Aerobic Exercise; Insulin Resistance; Cardiorespiratory Fitness
Keywords: Physical Activity; S100A8/A9; Myeloperoxidase; Monocyte Chemoattractant Protein-1; Interleukin-6; Inflammation
Keywords: Obesity; Exercise; Chitinase-3 Protein 1; Intelectin-1; Interleukin-6; Inflammation
Keywords: Obesity; Psychological Stress; Leptin; Interleukin-6; Lipopolysaccharide-Binding Protein
Keywords: PTX3; Palmitate; Atherosclerosis; Inflammatory Cytokines; Interleukin-10
Keywords: FGF21; Interleukin-6; Tumor necrosis factor-alpha; Energy Expenditure; Insulin Resistance
KEYWORDS: G protein-coupled receptor kinase 2; Exercise; Gender; IL-6 Inflammation; Fitness
Published by Elsevier Inc.
HIGHLIGHTS:
1. Acute exercise is a small source of oxidative stress while chronic exercise elicits protective adaptations against oxidative damage.
2. Chronic ingestion of energy-rich foods may contribute to obesity, while acute ingestion may also elicit potentially adverse metabolic responses including oxidative stress.
3. Caloric restriction may attenuate oxidative stress and serve as a beneficial weight loss intervention for obese individuals.
KEYWORDS: Brain-derived neurotrophic factor; Obesity; Lipopolysaccharide; Interleukin-6; Tumor necrosis factor-α
HIGHLIGHTS
• PBMCs from obese individuals elicited greater LPS-induced BDNF and IL-6 levels ex vivo.
• LPS-activated human PBMCs showed a BDNF and IL-6 associative response.
• BDNF and IL-6 may work together to lead to the neuroprotective effect in obesity.
Published by Elsevier Inc.
Keywords: Pentraxin 3; Obesity; Aerobic Exercise; Insulin Resistance; Cardiorespiratory Fitness
Keywords: Physical Activity; S100A8/A9; Myeloperoxidase; Monocyte Chemoattractant Protein-1; Interleukin-6; Inflammation
Keywords: Obesity; Exercise; Chitinase-3 Protein 1; Intelectin-1; Interleukin-6; Inflammation
Keywords: Obesity; Psychological Stress; Leptin; Interleukin-6; Lipopolysaccharide-Binding Protein
Keywords: PTX3; Palmitate; Atherosclerosis; Inflammatory Cytokines; Interleukin-10
Keywords: FGF21; Interleukin-6; Tumor necrosis factor-alpha; Energy Expenditure; Insulin Resistance
KEYWORDS: G protein-coupled receptor kinase 2; Exercise; Gender; IL-6 Inflammation; Fitness
Published by Elsevier Inc.
HIGHLIGHTS:
1. Acute exercise is a small source of oxidative stress while chronic exercise elicits protective adaptations against oxidative damage.
2. Chronic ingestion of energy-rich foods may contribute to obesity, while acute ingestion may also elicit potentially adverse metabolic responses including oxidative stress.
3. Caloric restriction may attenuate oxidative stress and serve as a beneficial weight loss intervention for obese individuals.
KEYWORDS: Brain-derived neurotrophic factor; Obesity; Lipopolysaccharide; Interleukin-6; Tumor necrosis factor-α
HIGHLIGHTS
• PBMCs from obese individuals elicited greater LPS-induced BDNF and IL-6 levels ex vivo.
• LPS-activated human PBMCs showed a BDNF and IL-6 associative response.
• BDNF and IL-6 may work together to lead to the neuroprotective effect in obesity.
Published by Elsevier Inc.