David Bartlett

Overview:

David Bartlett is an Assistant Professor in the Department of Medicine, Division of Medical Oncology. He earned his PhD in Immunology from the University of Birmingham, England where he specialized in the effects of exercise and lifestyles on immune function and systemic inflammation in the elderly. He was awarded a coveted Marie Curie Outgoing Fellowship from the European Union which brought him to Duke under the guidance of William Kraus, MD where he assessed the immunological and physiological responses of exercise training in patients with prediabetes and rheumatoid arthritis. His laboratory studies the effects of exercise and energy balance on immune function and physiology of patient groups including cancer, arthritis and diabetes. His research program is focused on human studies employing a wide range of techniques including human physiological testing, exercise training to in vitro and ex vivo cellular assays. 

Positions:

Assistant Professor in Medicine

Medicine, Medical Oncology
School of Medicine

Member of the Duke Cancer Institute

Duke Cancer Institute
School of Medicine

Member of Duke Molecular Physiology Institute

Duke Molecular Physiology Institute
School of Medicine

Education:

Ph.D. 2014

University of Birmingham

Grants:

Publications:

Lifestyle Interventions to Improve Immunesenescence

Authors
Bartlett, DB; Huffman, KM
MLA Citation
Bartlett, David B., and Kim M. Huffman. “Lifestyle Interventions to Improve Immunesenescence.” The Ageing Immune System and Health, Springer International Publishing, 2017, pp. 161–76. Crossref, doi:10.1007/978-3-319-43365-3_10.
URI
https://scholars.duke.edu/individual/pub1153554
Source
crossref
Published Date
Start Page
161
End Page
176
DOI
10.1007/978-3-319-43365-3_10

Association of the Composite Inflammatory Biomarker GlycA, with Exercise-Induced Changes in Body Habitus in Men and Women with Prediabetes.

GlycA is a new composite measure of systemic inflammation and a predictor of many inflammatory diseases. GlycA is the nuclear magnetic resonance spectroscopy-derived signal arising from glucosamine residues on acute-phase proteins. This study aimed to evaluate how exercise-based lifestyle interventions modulate GlycA in persons at risk for type 2 diabetes. GlycA, fitness, and body habitus were measured in 169 sedentary adults (45-75 years) with prediabetes randomly assigned to one of four six-month exercise-based lifestyle interventions. Interventions included exercise prescription based on the amount (energy expenditure (kcal/kg weight/week (KKW)) and intensity (%VO2peak). The groups were (1) low-amount/moderate-intensity (10KKW/50%) exercise; (2) high-amount/moderate-intensity (16KKW/50%) exercise; (3) high-amount/vigorous-intensity (16KKW/75%) exercise; and (4) a Clinical Lifestyle (combined diet plus low-amount/moderate-intensity exercise) intervention. Six months of exercise training and/or diet-reduced GlycA (mean Δ: -6.8 ± 29.2 μmol/L; p = 0.006) and increased VO2peak (mean Δ: 1.98 ± 2.6 mL/kg/min; p < 0.001). Further, visceral (mean Δ: -21.1 ± 36.6 cm2) and subcutaneous fat (mean Δ: -24.3 ± 41.0 cm2) were reduced, while liver density (mean Δ: +2.3 ± 6.5HU) increased, all p < 0.001. When including individuals in all four interventions, GlycA reductions were associated with reductions in visceral adiposity (p < 0.03). Exercise-based lifestyle interventions reduced GlycA concentrations through mechanisms related to exercise-induced modulations of visceral adiposity. This trial is registered with Clinical Trial Registration Number NCT00962962.
Authors
Bartlett, DB; Slentz, CA; Connelly, MA; Piner, LW; Willis, LH; Bateman, LA; Granville, EO; Bales, CW; Huffman, KM; Kraus, WE
MLA Citation
Bartlett, David B., et al. “Association of the Composite Inflammatory Biomarker GlycA, with Exercise-Induced Changes in Body Habitus in Men and Women with Prediabetes..” Oxid Med Cell Longev, vol. 2017, 2017. Pubmed, doi:10.1155/2017/5608287.
URI
https://scholars.duke.edu/individual/pub1259229
PMID
28642810
Source
pubmed
Published In
Oxid Med Cell Longev
Volume
2017
Published Date
Start Page
5608287
DOI
10.1155/2017/5608287

Neutrophil and Monocyte Bactericidal Responses to 10 Weeks of Low-Volume High-Intensity Interval or Moderate-Intensity Continuous Training in Sedentary Adults.

Neutrophils and monocytes are key components of the innate immune system that undergo age-associated declines in function. This study compared the impact of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on immune function in sedentary adults. Twenty-seven (43 ± 11 years) healthy sedentary adults were randomized into ten weeks of either a HIIT (>90% maximum heart rate) or MICT (70% maximum heart rate) group training program. Aerobic capacity (VO2peak), neutrophil and monocyte bacterial phagocytosis and oxidative burst, cell surface receptor expression, and systemic inflammation were measured before and after the training. Total exercise time commitment was 57% less for HIIT compared to that for MICT while both significantly improved VO2peak similarly. Neutrophil phagocytosis and oxidative burst and monocyte phagocytosis and percentage of monocytes producing an oxidative burst were improved by training similarly in both groups. Expression of monocyte but not neutrophil CD16, TLR2, and TLR4 was reduced by training similarly in both groups. No differences in systemic inflammation were observed for training; however, leptin was reduced in the MICT group only. With similar immune-enhancing effects for HIIT compared to those for MICT at 50% of the time commitment, our results support HIIT as a time efficient exercise option to improve neutrophil and monocyte function.
Authors
Bartlett, DB; Shepherd, SO; Wilson, OJ; Adlan, AM; Wagenmakers, AJM; Shaw, CS; Lord, JM
MLA Citation
Bartlett, David B., et al. “Neutrophil and Monocyte Bactericidal Responses to 10 Weeks of Low-Volume High-Intensity Interval or Moderate-Intensity Continuous Training in Sedentary Adults..” Oxid Med Cell Longev, vol. 2017, 2017. Pubmed, doi:10.1155/2017/8148742.
URI
https://scholars.duke.edu/individual/pub1261948
PMID
28656073
Source
pubmed
Published In
Oxid Med Cell Longev
Volume
2017
Published Date
Start Page
8148742
DOI
10.1155/2017/8148742

Habitual physical activity is associated with the maintenance of neutrophil migratory dynamics in healthy older adults.

BACKGROUND: Dysfunctional neutrophils with advanced age are a hallmark of immunosenescence. Reduced migration and bactericidal activity increase the risk of infection. It remains unclear why neutrophil dysfunction occurs with age. Physical activity and structured exercise have been suggested to improve immune function in the elderly. The aim of this study was to assess a comprehensive range of neutrophil functions and determine their association with habitual physical activity. METHOD: Physical activity levels were determined in 211 elderly (67±5years) individuals by 7-days of accelerometry wear. Twenty of the most physically active men and women were matched for age and gender to twenty of the least physically active individuals. Groups were compared for neutrophil migration, phagocytosis, oxidative burst, cell surface receptor expression, metabolic health parameters and systemic inflammation. Groups were also compared against ten young participants (23±4years). RESULTS: The most active group completed over twice as many steps/day as the least active group (p<0.001), had lower BMI's (p=0.007) and body fat percentages (p=0.029). Neutrophils migrated towards IL-8 better in the most active group compared to the least active (p<0.05) and was comparable to that of the young (p>0.05). These differences remained after adjusting for BMI, body fat and plasma metabolic markers which were different between groups. Correlations revealed that steps/day, higher adiponectin and lower insulin were positively associated with migratory ability (p<0.05). There was no difference in expression of the chemokine receptors CXCR1 or CXCR2 (p>0.05 for both). CD11b was higher in the most active group compared to the least active (p=0.048). No differences between activity groups or young controls were observed for neutrophil phagocytosis or oxidative burst in response to Escherichia coli (p>0.05). The young group had lower concentrations of IL-6, IL-8, MCP-1, CRP, IL-10 and IL-13 (p<0.05 for all) with no differences between the two older groups. CONCLUSION: These data suggest that impaired neutrophil migration, but not bactericidal function, in older adults may be, in part, the result of reduced physical activity. A 2-fold difference in physical activity is associated with better preserved neutrophil migratory dynamics in healthy older people. As a consequence increasing habitual physical activity may be beneficial for neutrophil mediated immunity.
Authors
Bartlett, DB; Fox, O; McNulty, CL; Greenwood, HL; Murphy, L; Sapey, E; Goodman, M; Crabtree, N; Thøgersen-Ntoumani, C; Fisher, JP; Wagenmakers, AJM; Lord, JM
MLA Citation
Bartlett, David B., et al. “Habitual physical activity is associated with the maintenance of neutrophil migratory dynamics in healthy older adults..” Brain Behav Immun, vol. 56, Aug. 2016, pp. 12–20. Pubmed, doi:10.1016/j.bbi.2016.02.024.
URI
https://scholars.duke.edu/individual/pub1153544
PMID
26928196
Source
pubmed
Published In
Brain Behav Immun
Volume
56
Published Date
Start Page
12
End Page
20
DOI
10.1016/j.bbi.2016.02.024

A novel inflammatory biomarker, GlycA, associates with disease activity in rheumatoid arthritis and cardio-metabolic risk in BMI-matched controls.

BACKGROUND: RA and CVD both have inflammation as part of the underlying biology. Our objective was to explore the relationships of GlycA, a measure of glycosylated acute phase proteins, with inflammation and cardiometabolic risk in RA, and explore whether these relationships were similar to those for persons without RA. METHODS: Plasma GlycA was determined for 50 individuals with mild-moderate RA disease activity and 39 controls matched for age, gender, and body mass index (BMI). Regression analyses were performed to assess relationships between GlycA and important markers of traditional inflammation and cardio-metabolic health: inflammatory cytokines, disease activity, measures of adiposity and insulin resistance. RESULTS: On average, RA activity was low (DAS-28 = 3.0 ± 1.4). Traditional inflammatory markers, ESR, hsCRP, IL-1β, IL-6, IL-18 and TNF-α were greater in RA versus controls (P < 0.05 for all). GlycA concentrations were significantly elevated in RA versus controls (P = 0.036). In RA, greater GlycA associated with disease activity (DAS-28; RDAS-28 = 0.5) and inflammation (RESR = 0.7, RhsCRP = 0.7, RIL-6 = 0.3: P < 0.05 for all); in BMI-matched controls, these inflammatory associations were absent or weaker (hsCRP), but GlycA was related to IL-18 (RhsCRP = 0.3, RIL-18 = 0.4: P < 0.05). In RA, greater GlycA associated with more total abdominal adiposity and less muscle density (Rabdominal-adiposity = 0.3, Rmuscle-density = -0.3, P < 0.05 for both). In BMI-matched controls, GlycA associated with more cardio-metabolic markers: BMI, waist circumference, adiposity measures and insulin resistance (R = 0.3-0.6, P < 0.05 for all). CONCLUSIONS: GlycA provides an integrated measure of inflammation with contributions from traditional inflammatory markers and cardio-metabolic sources, dominated by inflammatory markers in persons with RA and cardio-metabolic factors in those without.
Authors
Bartlett, DB; Connelly, MA; AbouAssi, H; Bateman, LA; Tune, KN; Huebner, JL; Kraus, VB; Winegar, DA; Otvos, JD; Kraus, WE; Huffman, KM
MLA Citation
Bartlett, David B., et al. “A novel inflammatory biomarker, GlycA, associates with disease activity in rheumatoid arthritis and cardio-metabolic risk in BMI-matched controls..” Arthritis Res Ther, vol. 18, Apr. 2016. Pubmed, doi:10.1186/s13075-016-0982-5.
URI
https://scholars.duke.edu/individual/pub1129553
PMID
27067270
Source
pubmed
Published In
Arthritis Research & Therapy
Volume
18
Published Date
Start Page
86
DOI
10.1186/s13075-016-0982-5