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214 results on '"Parker, Lewan"'

7. The effect of prednisolone ingestion and acute exercise on lipocalin-2 and its variants in young men: a pilot randomised crossover study.

Author

Bauer, Carlie, Patten, Rhiannon K., Sun, Qiyang, Li, Haoyun, Konja, Daniels, Woessner, Mary, Lin, Xuzhu, Garnham, Andrew, Hare, David L., Ebeling, Peter R., Sim, Marc, Lewis, Joshua R., Wang, Yu, Parker, Lewan, and Levinger, Itamar

Subjects
INSULIN sensitivity, MEDICAL sciences, LIPOCALIN-2, HEART beat, COOLDOWN
Abstract

Lipocalin-2 (LCN2) has three main variants; polyaminated (hLCN2) and non-polyaminated (C87A and R81E). The polyaminated form is proposed to positively influence energy control, whereas the non-polyaminated forms negatively impact energy control in mice. Glucocorticoids negatively affect glucose regulation and exercise has a positive effect. We hypothesise that glucocorticoids will suppress, while exercise will increase hLCN2, and decrease C87A and R81E, which will be associated with improved insulin sensitivity. In a randomised crossover design, nine young healthy men (aged 27.8 ± 4.9 years; BMI 24.4 ± 2.4 kg/m2) completed 30 min of high-intensity aerobic exercise (90–95% heart rate reserve) after glucocorticoid or placebo ingestion. Blood was collected and analyzed for LCN2 and its variants levels at baseline, immediately, 60 min and 180 min post-exercise. Insulin sensitivity was assessed using hyperinsulinemic-euglycemic clamp. A main effect, increase in LCN2 was detected for prednisolone ingestion (overall treatment effect p = 0.001), but not LCN2 variants (all p > 0.05). Main effects for time were observed for exercise for LCN2 and all variants (overall time effect all p < 0.02). Regardless of treatment, LCN2, C87A, R81E, and hLCN2 increased immediately after exercise compared with baseline (all p < 0.04). C87A, but not LCN2 or its other variants, remained elevated at 180 min post-ex (p = 0.007). LCN2, but not its variants, was elevated in response to prednisolone ingestion. LCN2 and its variants are transiently increased by acute exercise, but this increase was not related to insulin sensitivity. The clinical implication of elevated LCN2 and its variants post-exercise on satiety and energy regulation, as well as the mechanisms involved warrant further investigation. Clinical trial registration: www.anzctr.org.au, ACTRN12615000755538. [ABSTRACT FROM AUTHOR]

Published
2025
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14. Short-term high-calorie high-fat feeding induces hyperinsulinemia and blunts skeletal muscle microvascular blood flow in healthy humans

Author

Brayner, Barbara, primary, Keske, Michelle A., additional, Roberts-Thomson, Katherine M, additional, Parker, Lewan, additional, Betik, Andrew C., additional, Thomas, Hannah J., additional, Mason, Shaun, additional, Way, Kimberley L, additional, Livingstone, Katherine M, additional, Hamilton, D. Lee, additional, and Kaur, Gunveen, additional

Published
2024
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15. Osteocalcin and its forms across the lifespan in adult men

Author

Smith, Cassandra, Voisin, Sarah, Al Saedi, Ahmed, Phu, Steven, Brennan-Speranza, Tara, Parker, Lewan, Eynon, Nir, Hiam, Danielle, Yan, Xu, Scott, David, Blekkenhorst, Lauren C., Lewis, Joshua R., Seeman, Ego, Byrnes, Elizabeth, Flicker, Leon, Duque, Gustavo, Yeap, Bu B., and Levinger, Itamar

Published
2020
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22. Impaired postprandial adipose tissue microvascular blood flow responses to a mixed-nutrient meal in first-degree relatives of adults with type 2 diabetes

Author

Roberts-Thomson, Katherine M., primary, Hu, Donghua, additional, Russell, Ryan D., additional, Greenaway, Timothy, additional, Betik, Andrew C., additional, Parker, Lewan, additional, Kaur, Gunveen, additional, Richards, Stephen M., additional, Premilovac, Dino, additional, Wadley, Glenn D., additional, and Keske, Michelle A., additional

Published
2022
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24. The Effects of Acute High‐Intensity Interval Exercise and Hyperinsulinemic‐Euglycemic Clamp on Osteoglycin Levels in Young and Middle‐Aged Men

Author

Bauer, Carlie, primary, Tacey, Alexander, additional, Garnham, Andrew, additional, Smith, Cassandra, additional, Woessner, Mary N, additional, Lin, Xuzhu, additional, Zarekookandeh, Navabeh, additional, Hare, David L, additional, Lewis, Joshua R, additional, Parker, Lewan, additional, and Levinger, Itamar, additional

Published
2022
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28. The effects of acute high-intensity interval exercise and hyperinsulinemic-euglycemic clamp on osteoglycin levels in young and middle-aged men

Author

Bauer, Carlie, Tacey, Alexander, Garnham, Andrew, Smith, Cassandra, Woessner, Mary N., Lin, Xuzhu, Zarekookandeh, Navabeh, Hare, David L., Lewis, Joshua R., Parker, Lewan, Levinger, Itamar, Bauer, Carlie, Tacey, Alexander, Garnham, Andrew, Smith, Cassandra, Woessner, Mary N., Lin, Xuzhu, Zarekookandeh, Navabeh, Hare, David L., Lewis, Joshua R., Parker, Lewan, and Levinger, Itamar

Abstract

Osteoglycin (OGN) is a leucine-rich proteoglycan that has been implicated in the regulation of glucose in animal models. However, its relationship with glucose control in humans is unclear. We examined the effect of high-intensity interval exercise (HIIE) and hyperinsulinemic-euglycemic clamp on circulating levels of OGN as well as whether circulating OGN levels are associated with markers of glycemic control and cardio-metabolic health. Serum was analyzed for OGN (ELISA) levels from 9 middle-aged obese men (58.1 ± 2.2 years, body mass index [BMI] = 33.1 ± 1.4 kg∙m − 2, mean ± SEM) and 9 young men (27.8 ± 1.6 years, BMI = 24.4 ± 0.08 kg∙m − 2) who previously completed a study involving a euglycemic-hyperinsulinemic clamp at rest and after HIIE (4 x 4 minutes cycling at approximately 95% peak heart rate (HRpeak), interspersed with 2 minutes of active recovery). Blood pressure, body composition (dual-energy X-ray absorptiometry), and insulin sensitivity (hyperinsulinemic-euglycemic clamp) were assessed. Serum OGN was higher in the young cohort compared with the middle-aged cohort (65.2 ± 10.1 ng/mL versus 36.5 ± 4. 5 ng/mL, p ≤ 0.05). Serum OGN was unaffected by acute HIIE but decreased after the insulin clamp compared with baseline (~ − 27 %, p = 0.01), post-exercise (~ − 35 %, p = 0.01), and pre-clamp (~ − 32 %, p = 0.02) time points, irrespective of age. At baseline, lower circulating OGN levels were associated with increased age, BMI, and fat mass, whereas higher OGN levels were related to lower fasting glucose. Higher OGN levels were associated with a higher glucose infusion rate. Exercise had a limited effect on circulating OGN. The mechanisms by which OGN affects glucose regulation should be explored in the future.

Published
2022

29. Additional file 1 of Long non-coding RNA Tug1 modulates mitochondrial and myogenic responses to exercise in skeletal muscle

Author

Trewin, Adam J., Silver, Jessica, Dillon, Hayley T., Della Gatta, Paul A., Parker, Lewan, Hiam, Danielle S., Lee, Yin Peng, Richardson, Mark, Wadley, Glenn D., and Lamon, Séverine

Abstract

Additional file 1: Figure S1: Expression of lncRNA TUG1 transcript variants in male and female human skeletal muscle. Figure S2: Optimisation of Tug1 knockdown in C2C12 myocytes and uncropped western blot images. Figure S3: Mitochondrial morphology in myotubes with Tug1 knockdown, supplement to Fig. 3. Figure S4: Tug1 knockdown in cells used for mitochondrial respiration experiments, related to Fig. 4. Figure S5: Supporting data for transcriptomic responses to EPS and Tug1 KD, related to Figs. 6 and 7. Individual data are available at DOI: 10.6084/m9.figshare.20175770 [24].

Published
2022
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33. Osteoglycin Across the Adult Lifespan

Author

Woessner, Mary N, primary, Hiam, Danielle, additional, Smith, Cassandra, additional, Lin, Xuzhu, additional, Zarekookandeh, Navabeh, additional, Tacey, Alexander, additional, Parker, Lewan, additional, Landen, Shanie, additional, Jacques, Macsue, additional, Lewis, Joshua R, additional, Brennan-Speranza, Tara, additional, Voisin, Sarah, additional, Duque, Gustavo, additional, Eynon, Nir, additional, and Levinger, Itamar, additional

Published
2021
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36. Impaired postprandial skeletal muscle vascular responses to a mixed meal challenge in normoglycaemic people with a parent with type 2 diabetes

Author

Russell, Ryan D., primary, Roberts-Thomson, Katherine M., additional, Hu, Donghua, additional, Greenaway, Timothy, additional, Betik, Andrew C., additional, Parker, Lewan, additional, Sharman, James E., additional, Richards, Stephen M., additional, Rattigan, Stephen, additional, Premilovac, Dino, additional, Wadley, Glenn D., additional, and Keske, Michelle A., additional

Published
2021
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38. Impaired postprandial skeletal muscle vascular responses to a mixed meal challenge in normoglycaemic people with a parent with type 2 diabetes

Author

Russell, RD, Thomson, KM, Hu, D, Greenaway, T, Betik, Andrew, Parker, Lewan, Sharman, JE, Richards, SM, Rattigan, S, Premilovac, D, Wadley, Glenn, Keske, Michelle, Russell, RD, Thomson, KM, Hu, D, Greenaway, T, Betik, Andrew, Parker, Lewan, Sharman, JE, Richards, SM, Rattigan, S, Premilovac, D, Wadley, Glenn, and Keske, Michelle

Published
2021

45. Osteoglycin Across the Adult Lifespan.

Author

Woessner, Mary N., Hiam, Danielle, Smith, Cassandra, Xuzhu Lin, Zarekookandeh, Navabeh, Tacey, Alexander, Parker, Lewan, Landen, Shanie, Jacques, Macsue, Lewis, Joshua R., Brennan-Speranza, Tara, Voisin, Sarah, Duque, Gustavo, Eynon, Nir, and Levinger, Itamar

Abstract

Context: Osteoglycin (OGN) is a proteoglycan released from bone and muscle which has been associated with markers of metabolic health. However, it is not clear whether the levels of circulating OGN change throughout the adult lifespan or if they are associated with clinical metabolic markers or fitness. Objective: We aimed to identify the levels of circulating OGN across the lifespan and to further explore the relationship between OGN and aerobic capacity as well as OGN’s association with glucose and HOMA-IR. Methods: 107 individuals (46 males and 61 females) aged 21-87 years were included in the study. Serum OGN levels, aerobic capacity (VO2peak), glucose, and homeostatic model assessment for insulin resistance (HOMA-IR) were assessed. T-tests were used to compare participant characteristics between sexes. Regression analyses were performed to assess the relationship between OGN and age, and OGN and fitness and metabolic markers. Results: OGN displayed a nonlinear, weak “U-shaped” relationship with age across both sexes. Men had higher levels of OGN than women across the lifespan (β = 0.23, P = .03). Age and sex explained 16% of the variance in OGN (adjusted R² = 0.16; P < .001). Higher OGN was associated with higher VO2peak (β = 0.02, P = .001); however, those aged <50 showed a stronger positive relationship than those aged >50. A higher OGN level was associated with a higher circulating glucose level (β = 0.17, P < .01). No association was observed between OGN and HOMA-IR. Conclusion: OGN was characterized by a U-shaped curve across the lifespan which was similar between sexes. Those with a higher aerobic capacity or higher glucose concentration had higher OGN levels. Our data suggest an association between OGN and aerobic fitness and glucose regulation. Future studies should focus on exploring the potential of OGN as a biomarker for chronic disease. [ABSTRACT FROM AUTHOR]

Published
2022
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46. High-glucose mixed-nutrient meal ingestion impairs skeletal muscle microvascular blood flow in healthy young men

Author

Parker, Lewan, Morrison, Dale J., Beti, Andrew C., Roberts-Thomson, Katherine, Kaur, Gunveen, Wadley, Glenn D., Sha, Christopher S., Kesk, Michelle A., Parker, Lewan, Morrison, Dale J., Beti, Andrew C., Roberts-Thomson, Katherine, Kaur, Gunveen, Wadley, Glenn D., Sha, Christopher S., and Kesk, Michelle A.

Abstract

Oral glucose ingestion leads to impaired muscle microvascular blood flow (MBF), which may contribute to acute hyperglycemia-induced insulin resistance. We investigated whether incorporating lipids and protein into a high-glucose load would prevent postprandial MBF dysfunction. Ten healthy young men (age, 27 yr [24, 30], mean with lower and upper bounds of the 95% confidence interval; height, 180 cm [174, 185]; weight, 77 kg [70, 84]) ingested a high-glucose (1.1 g/kg glucose) mixed-nutrient meal (10 kcal/kg; 45% carbohydrate, 20% protein, and 35% fat) in the morning after an overnight fast. Femoral arterial blood flow was measured via Doppler ultrasound, and thigh MBF was measured via contrast-enhanced ultrasound, before meal ingestion and 1 h and 2 h postprandially. Blood glucose and plasma insulin were measured at baseline and every 15 min throughout the 2-h postprandial period. Compared with baseline, thigh muscle microvascular blood volume, velocity, and flow were significantly impaired at 60 min postprandial (−25%, −27%, and −46%, respectively; all P < 0.05) and to a greater extent at 120 min postprandial (−37%, −46%, and −64%; all P < 0.01). Heart rate and femoral arterial diameter, blood velocity, and blood flow were significantly increased at 60 min and 120 min postprandial (all P < 0.05). Higher blood glucose area under the curve was correlated with greater MBF dysfunction ( R2 = 0.742; P < 0.001). Ingestion of a high-glucose mixed-nutrient meal impairs MBF in healthy individuals for up to 2 h postprandial

Published
2020

48. Postprandial microvascular blood flow in skeletal muscle: Similarities and disparities to the hyperinsulinaemic-euglycaemic clamp

Author

Roberts-Thomson, Katherine M., Betik, Andrew C., Premilovac, Dino, Rattigan, Stephen, Richards, Stephen M., Ross, Renee M., Russell, Ryan D., Kaur, Gunveen, Parker, Lewan, Keske, Michelle A., Roberts-Thomson, Katherine M., Betik, Andrew C., Premilovac, Dino, Rattigan, Stephen, Richards, Stephen M., Ross, Renee M., Russell, Ryan D., Kaur, Gunveen, Parker, Lewan, and Keske, Michelle A.

Published
2020

49. Postprandial microvascular blood flow in skeletal muscle: Similarities and disparities to the hyperinsulinaemic‐euglycaemic clamp

Author

Roberts‐Thomson, Katherine M., primary, Betik, Andrew C., additional, Premilovac, Dino, additional, Rattigan, Stephen, additional, Richards, Stephen M., additional, Ross, Renee M., additional, Russell, Ryan D., additional, Kaur, Gunveen, additional, Parker, Lewan, additional, and Keske, Michelle A., additional

Published
2020
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