R. Lee Franco

Evaluation of a 6-month multi-disciplinary healthy weight management program targeting urban, overweight adolescents: Effects on physical fitness, physical activity, and blood lipid profiles

This study evaluated preliminary physical fitness, physical activity, and blood lipid profile data obtained from overweight adolescents upon enrolling in a healthy weight management program and following 6 months of program participation. One hundred and sixty-eight participants (13.4+/-1.8 years, 37.9+/-8.3 kg/m(2), 59.5% female and 76.2% African-American) enrolled in the program. The intervention addressed factors related to nutrition, physical activity, and other behaviors related to weight management. Sixty-four participants (38.1%) completed 6 months of program participation. While there was no significant reduction in body mass or body mass index (BMI), BMI z-score was reduced by 1.2% (p < 0.05), cardiorespiratory fitness was increased by 10.8% (p = 0.001), body fat percentage was reduced by 2.6% (p = 0.001), total cholesterol was reduced by 7.2% (p < 0.001), and low density lipoprotein (LDL-C) was reduced by 8.4% (p < 0.001) at 6 months. Continued development and evaluation of programs designed to prevent and treat child and adolescent overweight is warranted to address this major public health issue.

LPS-stimulated tumor necrosis factor-alpha and interleukin-6 mRNA and cytokine responses following acute psychological stress

The purpose of this study was to examine the effect of acute psychological stress on LPS-stimulated TNF-α and IL-6 mRNA expression. Twenty-one healthy male subjects participated in 20 min of acute stress. Blood samples for norepinephrine and LPS-stimulated TNF-α and IL-6 cytokines and mRNA were drawn prior to, immediately after and 1-h after stress. Stress-induced increases in anxiety scores, cortisol, plasma norepinephrine, and heart rate demonstrated that the experimental protocol elicited an acute stress response. LPS-stimulated TNF-α mRNA decreased significantly immediately post-stress and partially recovered at 1h post-stress, whereas LPS-stimulated IL-6 mRNA exhibited a significant change across time, with an increase immediately after stress and a decrease 1h after stress. Trends in LPS-stimulated TNF-α and IL-6 cytokine concentrations followed the patterns of mRNA expression. A negative correlation of body mass index (BMI) and percent change of LPS-stimulated TNF-α mRNA was observed immediately post-stress, and BMI positively correlated with percent change of LPS-stimulated IL-6 cytokine levels immediately following stress. These findings demonstrated that acute psychological stress affects LPS-stimulated IL-6 and TNF-α gene expression. These results also indicate that BMI may impact the effects of psychological stress on cytokine responses to immune challenge. Further examination of the effects of stress on synthesis of other cellular cytokines and investigation of the association of BMI and stress responses will provide a more clear representation of the cytokine responses to acute psychological stress. In addition, studies examining the influence of gender on the response of immune cell subsets to acute stress and the possible mediating effect of BMI are warranted.

Effects of mental challenge on neurovascular responses in healthy male subjects.

The purpose of this study was to examine the effects of mental challenge on total antioxidant capacity (TAC), forearm blood flow (FBF), vascular reactivity (VR), and the release of norepinephrine (NE). Furthermore, this study also examined the possible relationships of NE with FBF and VR following the mental challenge. Twenty healthy male subjects participated in twenty minutes of mental stress task (Stroop Color-Word Task [SCW] and mental arithmetic task [MA]). Our results showed that HR and NE increased significantly immediately following the mental challenge, whereas total antioxidant capacity did not change. Furthermore, the area-under-the-curves (AUCs) for both FBF at baseline and during reactive hyperemia, and VR elicited a significant change across time immediately post-stress. The percent change in the HR was partially correlated with the percent change in the VR immediately post-stress (p=0.08). Additionally, the percent change in the NE was positively correlated with TAC immediately post-stress, whereas NE only demonstrated a partial relationship with FBF at baseline immediately following the mental challenge (p=0.10). These findings suggest that forearm vasodilation following the mental challenge may be mediated by the antioxidant defense and sympathetic activation. Further studies are warranted to elucidate the mechanisms that explain the responses and relationships presented in this investigation.

The effect of acute physical and mental stress on soluble cellular adhesion molecule concentration.

AIMS This study investigated the impact of acute physical and mental stress on serum concentrations of vascular cell adhesion molecule (VCAM)-1 and CX3CL1/fractalkine. MATERIALS AND METHODS Male volunteers (n=20; 21.3±0.55years of age) completed a graded treadmill test to exhaustion and a 20-minute mental stress task (Stroop Color-Word Test, mental arithmetic) on separate, non-consecutive days. Heart rate (HR) was measured at baseline and throughout exercise and mental stress. Blood was collected at baseline (PRE), immediately following (POST) and 30min after (POST30) exercise and mental stress. Soluble VCAM-1 and fractalkine were quantified in participant serum via enzyme-linked immunosorbent assays. KEY FINDINGS Both treadmill exercise and the mental stress task significantly increased participant HR; although, exercise resulted in a substantially greater increase in participant HR compared to mental stress (197.82±11.99 vs. 38.67±3.10% [p<0.001]). VCAM-1 (815.74±139.55 vs. 738.67±131.59ng/mL [p=0.002]) and fractalkine (1.032±0.33 vs. 0.59±0.20ng/mL [p<0.001]) were significantly elevated in participant serum POST maximal exercise before returning to values similar to baseline at POST30. The acute mental stress task did not significantly alter serum VCAM-1 or fractalkine at any time point. SIGNIFICANCE In conclusion, maximal aerobic exercise results in a significant elevation of the soluble adhesion molecules VCAM-1 and fractalkine in the serum of adult males that does not occur following laboratory-induced mental stress. The findings of the current investigation may suggest a novel protective role for acute aerobic exercise in vascular health via exercise-induced CAM proteolysis.

G protein-coupled receptor kinase-2 in peripheral blood mononuclear cells following acute mental stress.

AIMS This study investigated G-protein-coupled receptor kinase-2 (GRK2) density in peripheral blood mononuclear cells (PBMC) and its relationship to plasma pro-inflammatory cytokine concentrations following acute mental stress. MAIN METHODS Apparently healthy males (n=20; 21.3±0.55years) participated in an acute mental stress task. Heart rate was measured at baseline and throughout mental stress. Plasma epinephrine (EPI), norepinephrine (NE), tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) were assessed via enzyme-linked immunosorbent assays before, immediately following, and 30, 60 and 120min after the mental stress task. GRK2 density was measured by western blot technique at the same time points. KEY FINDINGS Acute mental stress elicited significant elevations in HR, and plasma EPI and NE. Additionally, GRK2 density increased significantly across time following the stress task. Post hoc analyses revealed that GRK2 density was significantly elevated at 30 and 60min following acute stress. A significant positive correlation was observed between GRK2 density and plasma EPI, while a significant negative correlation was revealed between GRK2 density and TNF-α across all time points. SIGNIFICANCE Acute mental stress significantly increased GRK2 density in PBMCs of young adult males. Furthermore, although plasma IL-6 and TNF-α did not change following mental stress, it remains unknown whether a longer time period was needed to observe a pro-inflammatory state associated with the desensitization of β-adrenergic receptor activity. Our findings that GRK2 expression is promptly increased in PBMC following an acute stress task, may suggest a link between stress and intracellular inflammatory signaling.

Sympathetic Activity Assessed during Exercise Recovery in Young Obese Females.

OBJECTIVE To evaluate differences in sympathetic activity, as assessed by an exercise recovery index (ERI; heart rate/oxygen consumption [VO2] plateau), between black and white obese female adolescents. An additional aim was to determine the association of ERI with insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR]), cardiovascular fitness per fat-free mass (VO2 per fat-free mass), systolic blood pressure (SBP), and percent body fat (%FAT) in both black and white obese adolescents. STUDY DESIGN Sixty-one females volunteered to participate in this study. HOMA-IR, SBP, and %FAT were assessed during resting conditions in black (n = 49, 13.7 ± 1.6 years, 38.1 ± 6.1 kg/m(2)) and white (n = 12, 13.3 ± 2.2 years, 34.3 ± 4.9 kg/m(2)) obese adolescents. An ERI was calculated during a 5-minute passive recovery period immediately following a graded treadmill exercise test to exhaustion. RESULTS The ERI was significantly greater in black compared with white obese adolescent females (29.8 ± 6.4 vs 24.1 ± 3.1 bpm·mLO2(-1)·min(-1), P = .004). Using multiple linear regression modeling, there was a significant independent association between ERI and VO2 per fat-free mass (r = -0.310, P = .027) and %FAT (r = 0.326, P = .020) in black obese adolescents after controlling for HOMA-IR and SBP. CONCLUSIONS These results suggest that black obese adolescent females have greater sympathetic activity, as assessed by an ERI, than white obese adolescent females. These findings support the need for weight management efforts aimed at both reducing %FAT and improving fitness in obese adolescents, specifically black females. TRIAL REGISTRATION Registered with Clinicaltrials.gov: NCT00562293.