The Community Mentorship Program: Providing Community-Engagement Opportunities for Early-Stage Clinical and Translational Scientists to Facilitate Research Translation

PROBLEM

A goal of the Southern California Clinical and Translational Science Institute (SC-CTSI) at the University of Southern California and Children's Hospital Los Angeles is to train early-stage clinical and translational scientists (CTSs) to conduct research that improves the health of diverse communities. This goal aligns well with the Institute of Medicine's recommendations emphasizing community engagement in biomedical research that facilitates research translation. The Community Mentorship Program (CMP), created to complement community-engaged research didactics, matches CTSs with community mentors who help them identify and complete community-engaged experiences that inform their research.

APPROACH

The CMP was piloted in 2013-2015 by the SC-CTSI Workforce Development and Community Engagement cores. The CMP team matched three CTSs (assistant professors pursuing mentored career development awards) with mentors at community-based organizations (CBOs) aligned with their research interests. Each mentor-mentee pair signed a memorandum of understanding. The CMP team checked in regularly, monitoring progress and addressing challenges in CTSs' completion of their community-engaged experience.

OUTCOMES

Each pair completed at least one community-engaged activity informing the CTS's research. In exit interviews, the CTSs and CBO mentors expressed satisfaction with the program and stated that they would continue to work together. The CTSs reported that the program provided opportunities to develop networks outside academia, build trust within the community, and receive feedback and learn from individuals in communities affected by their research.

NEXT STEPS

The CMP will be expanded to include all eligible early-career CTSs and promoted for use in similar settings outside the SC-CTSI.

Changes in muscle mass, muscle strength, and power but not physical function are related to testosterone dose in healthy older men

OBJECTIVES

To examine the effect of graded doses of testosterone on physical function and muscle performance in healthy, older men.

DESIGN

Randomized, double-blind, placebo-controlled clinical trial.

SETTING

General clinical research center.

PARTICIPANTS

Community-dwelling healthy men aged 60 to 75 (N=44).

INTERVENTION

Monthly treatment with a gonadotropin-releasing hormone agonist plus 25, 50, 125, or 300 mg/wk of intramuscular injections of testosterone enanthate for 20 weeks.

MEASUREMENTS

Skeletal muscle mass (SMM) was estimated using dual-energy X-ray absorptiometry. Leg press strength was measured by one repetition maximum, leg power by Nottingham Leg Rig, and muscle fatigability by repetitions to failure in the leg press exercise. Stair climbing, 6-meter and 400-meter walking speed, and a timed-up-and-go (TUG) test were used to assess physical function.

RESULTS

Significant testosterone dose- and concentration-dependent increases were observed in SMM (P<.001) and maximal strength (P=.001) but not muscle fatigability. Leg power also increased dose-dependently (P=.048). In contrast, changes in self-selected normal and fast walking speed over 6 or 400 meters, stair climbing power, and time for the TUG were not significantly related to testosterone dose, testosterone concentrations, or changes in muscle strength or power, or SMM.

CONCLUSION

Testosterone administration was associated with dose-dependent increases in SMM, leg strength, and power but did not improve muscle fatigability or physical function. The observation that physical function scores did not improve linearly with strength suggests that these high-functioning older men were already in the asymptotic region of the curve describing the relationship between physical function and strength.

Effects of a supraphysiological dose of testosterone on physical function, muscle performance, mood, and fatigue in men with HIV-associated weight loss

Testosterone increases fat-free mass (FFM) in men infected with human immunodeficiency virus (HIV), but its effects on muscle performance, physical function, mood, and quality of life are poorly understood. Sixty-one HIV-infected men with weight loss were randomized to receive weekly intramuscular injections of 300 mg of testosterone enanthate or placebo for 16 wk. The primary outcome of interest was physical function (walking speed, stair-climbing power, and load-carrying ability). Secondary outcome measures included body weight and composition, muscle performance, sexual function, mood, and quality of life. Serum nadir free and total testosterone levels increased (+188.0 +/- 29.6 and +720 +/- 86 ng/dl) in the testosterone, but not placebo, group. Testosterone administration was associated with increased FFM (2.8 +/- 0.5 kg), which was significantly greater than in the placebo group (P < 0.0001). Leg press strength increased significantly in testosterone-treated (P = 0.027), but not placebo-treated, men; the difference between groups was not significant. Other measures of muscle performance and physical function did not change significantly in either group. Men receiving testosterone demonstrated significantly greater improvements in mental health and quality-of-life scores than those receiving placebo and improvements in fatigue/energy and mood scores that were not significantly different from those receiving placebo. Sexual function scores did not change in either group. In HIV-infected men with weight loss, a supraphysiological dose of testosterone significantly increased FFM but did not improve self-reported or performance-based measures of physical function. Improvements in mood, fatigue, and quality-of-life measures in the testosterone group, although clinically important, need further confirmation.

Dose-dependent effects of testosterone on sexual function, mood, and visuospatial cognition in older men

CONTEXT

The relationships between testosterone dose and its effects on sexual function, mood, and visuospatial cognition are poorly understood.

OBJECTIVE

To elucidate testosterone dose-response relationships in older men, we examined the effects of graded testosterone doses on sexual function, mood, and visuospatial cognition in healthy, older men (age, 60-75 yr).

SETTING

This study was performed at the General Clinical Research Center.

INTERVENTION/METHODS

Subjects each received a long-acting GnRH agonist to suppress endogenous testosterone production and were randomized to receive one of five doses (25, 50, 125, 300, and 600 mg) of testosterone enanthate weekly for 20 wk. Questionnaires were used to evaluate sexual function. Scores for overall sexual function as well as subcomponents of sexual function (libido, sexual activity, and erectile function) were calculated.

RESULTS

Changes in overall sexual function (P = 0.003) and waking erections (P = 0.024) differed by dose. An interaction between libido and being sexually active was observed, such that libido changed by testosterone dose only among men who reported being sexually active at the beginning of the study (P = 0.009). Men's log-transformed free testosterone levels during treatment were positively correlated with overall sexual function (P = 0.001), waking erections (P = 0.040), spontaneous erections (P = 0.047), and libido (P = 0.027), but not with intercourse frequency (P = 0.428) or masturbation frequency (P = 0.814). No effects of testosterone dose were observed on two measures of mood: Hamilton's Depression Inventory (P = 0.359) and Young's Mania Scale (P = 0.851). The number of trials completed on a computer-based test of visuospatial cognition differed by dose (P = 0.042), but the number of squares correctly completed on this task did not differ by dose (P = 0.159).

CONCLUSIONS

Different aspects of male behavior respond differently to testosterone. When considered together with previous data from young men, these data indicate that testosterone dose-response relationships for sexual function and visuospatial cognition differ in older and young men.

Effects of testosterone replacement in human immunodeficiency virus-infected women with weight loss

The objective of this study was to determine whether physiological testosterone replacement increases fat-free mass (FFM) and muscle strength and contributes to weight maintenance in HIV-infected women with relative androgen deficiency and weight loss. Fifty-two HIV-infected, medically stable women, 18-50 yr of age, with more than 5% weight loss over 6 months and testosterone levels below 33 ng/dl were randomized into this double-blind, placebo-controlled trial of 24-wk duration. Subjects in the testosterone group applied testosterone patches twice weekly to achieve a nominal delivery of 300 mug testosterone over 24 h. Data were evaluable for 44 women. Serum average total and peak testosterone levels increased significantly in the testosterone group, but did not change in the placebo group. However, there were no significant changes in FFM (testosterone, 0.7 +/- 0.4 kg; placebo, 0.3 +/- 0.4 kg), fat mass (testosterone, 0.3 +/- 0.7 kg; placebo, 0.6 +/- 0.7 kg), or body weight (testosterone, 1.0 +/- 0.9 kg; placebo, 0.9 +/- 0.8 kg) between the two treatment groups. There were no significant changes in leg press strength, leg power, or muscle fatigability in either group. Changes in quality of life, sexual function, cognitive function, and Karnofsky performance scores did not differ significantly between the two groups. High-density lipoprotein cholesterol levels decreased significantly in the testosterone group. The patches were well tolerated. We conclude that physiological testosterone replacement was safe and effective in raising testosterone levels into the mid to high normal range, but did not significantly increase FFM, body weight, or muscle performance in HIV-infected women with low testosterone levels and mild weight loss. Additional studies are needed to fully explore the role of androgens in the regulation of body composition in women.

Older men are as responsive as young men to the anabolic effects of graded doses of testosterone on the skeletal muscle

Although testosterone levels and muscle mass decline with age, many older men have serum testosterone level in the normal range, leading to speculation about whether older men are less sensitive to testosterone. We determined the responsiveness of androgen-dependent outcomes to graded testosterone doses in older men and compared it to that in young men. The participants in this randomized, double-blind trial were 60 ambulatory, healthy, older men, 60-75 yr of age, who had normal serum testosterone levels. Their responses to graded doses of testosterone were compared with previous data in 61 men, 19-35 yr old. The participants received a long-acting GnRH agonist to suppress endogenous testosterone production and 25, 50, 125, 300, or 600 mg testosterone enanthate weekly for 20 wk. Fat-free mass, fat mass, muscle strength, sexual function, mood, visuospatial cognition, hormone levels, and safety measures were evaluated before, during, and after treatment. Of 60 older men who were randomized, 52 completed the study. After adjusting for testosterone dose, changes in serum total testosterone (change, -6.8, -1.9, +16.1, +49.5, and +101.9 nmol/liter at 25, 50, 125, 300, and 600 mg/wk, respectively) and hemoglobin (change, -3.6, +9.9, +20.9, +12.6, and +29.4 g/liter at 25, 50, 125, 300, and 600 mg/wk, respectively) levels were dose-related in older men and significantly greater in older men than young men (each P < 0.0001). The changes in FFM (-0.3, +1.7, +4.2, +5.6, and +7.3 kg, respectively, in five ascending dose groups) and muscle strength in older men were correlated with testosterone dose and concentrations and were not significantly different in young and older men. Changes in fat mass correlated inversely with testosterone dose (r = -0.54; P < 0.001) and were significantly different in young vs. older men (P < 0.0001); young men receiving 25- and 50-mg doses gained more fat mass than older men (P < 0.0001). Mood and visuospatial cognition did not change significantly in either group. Frequency of hematocrit greater than 54%, leg edema, and prostate events were numerically higher in older men than in young men. Older men are as responsive as young men to testosterone's anabolic effects; however, older men have lower testosterone clearance rates, higher increments in hemoglobin, and a higher frequency of adverse effects. Although substantial gains in muscle mass and strength can be realized in older men with supraphysiological testosterone doses, these high doses are associated with a high frequency of adverse effects. The best trade-off was achieved with a testosterone dose (125 mg) that was associated with high normal testosterone levels, low frequency of adverse events, and significant gains in fat-free mass and muscle strength.

Testosterone dose-dependently increases maximal voluntary strength and leg power, but does not affect fatigability or specific tension

Testosterone supplementation in men increases fat-free mass, but whether measures of muscle performance, such as maximal voluntary strength, power, fatigability, or specific tension, are improved has not been determined. Furthermore, the extent to which these measures of muscle performance are related to testosterone dose or circulating concentration is unknown. To examine the relationship between testosterone dose and muscle performance, 61 healthy, eugonadal young men (aged 18-35 yr) were randomized to 1 of 5 groups, each receiving a long-acting GnRH agonist to suppress endogenous testosterone production plus weekly injections of 25, 50, 125, 300, or 600 mg testosterone enanthate for 20 wk. These doses produced mean nadir testosterone concentrations of 253, 306, 542, 1345, and 2370 ng/dl, respectively. Maximal voluntary muscle strength and fatigability were determined by a seated leg press exercise. Leg power was measured using a validated leg power instrument. Specific tension was estimated by the ratio of one repetition maximum muscle strength to thigh muscle volume determined by magnetic resonance imaging. Testosterone administration was associated with a dose-dependent increase in leg press strength and leg power, but muscle fatigability did not change significantly during treatment. Changes in leg press strength were significantly correlated with total (r = 0.46; P = 0.0005) and free (r = 0.38; P = 0.006) testosterone as was leg power (total testosterone: r = 0.38; P = 0.007; free testosterone: r = 0.35; P = 0.015), but not muscle fatigability. Serum IGF-I concentrations were not significantly correlated with leg strength, power, or fatigability. Specific tension did not change significantly at any dose. We conclude that the effects of testosterone on muscle performance are specific; it increases maximal voluntary strength and leg power, but does not affect fatigability or specific tension. The changes in leg strength and power are dependent on testosterone dose and circulating testosterone concentrations and exhibit a log-linear relationship with serum total and free testosterone. Failure to observe a significant testosterone dose relationship with fatigability suggests that testosterone does not affect this component of muscle performance and that different components of muscle performance are regulated by different mechanisms.

Testosterone dose-response relationships in healthy young men

Testosterone increases muscle mass and strength and regulates other physiological processes, but we do not know whether testosterone effects are dose dependent and whether dose requirements for maintaining various androgen-dependent processes are similar. To determine the effects of graded doses of testosterone on body composition, muscle size, strength, power, sexual and cognitive functions, prostate-specific antigen (PSA), plasma lipids, hemoglobin, and insulin-like growth factor I (IGF-I) levels, 61 eugonadal men, 18-35 yr, were randomized to one of five groups to receive monthly injections of a long-acting gonadotropin-releasing hormone (GnRH) agonist, to suppress endogenous testosterone secretion, and weekly injections of 25, 50, 125, 300, or 600 mg of testosterone enanthate for 20 wk. Energy and protein intakes were standardized. The administration of the GnRH agonist plus graded doses of testosterone resulted in mean nadir testosterone concentrations of 253, 306, 542, 1,345, and 2,370 ng/dl at the 25-, 50-, 125-, 300-, and 600-mg doses, respectively. Fat-free mass increased dose dependently in men receiving 125, 300, or 600 mg of testosterone weekly (change +3.4, 5.2, and 7.9 kg, respectively). The changes in fat-free mass were highly dependent on testosterone dose (P = 0.0001) and correlated with log testosterone concentrations (r = 0.73, P = 0.0001). Changes in leg press strength, leg power, thigh and quadriceps muscle volumes, hemoglobin, and IGF-I were positively correlated with testosterone concentrations, whereas changes in fat mass and plasma high-density lipoprotein (HDL) cholesterol were negatively correlated. Sexual function, visual-spatial cognition and mood, and PSA levels did not change significantly at any dose. We conclude that changes in circulating testosterone concentrations, induced by GnRH agonist and testosterone administration, are associated with testosterone dose- and concentration-dependent changes in fat-free mass, muscle size, strength and power, fat mass, hemoglobin, HDL cholesterol, and IGF-I levels, in conformity with a single linear dose-response relationship. However, different androgen-dependent processes have different testosterone dose-response relationships.