Sex differences in the impact of physical frailty on outcomes in heart failure

BACKGROUND

Physical frailty is strongly related to adverse outcomes in heart failure (HF), and women are more likely to be physically frail than men; however, it is unknown if this sex difference affects outcomes.

OBJECTIVES

To determine if there are sex differences in the associations between physical frailty and health-related quality of life (HRQOL) and clinical outcomes in HF.

METHODS

We conducted a prospective study of adults with HF. Physical frailty was assessed using the Frailty Phenotype Criteria. HRQOL was assessed using the Minnesota Living with HF Questionnaire. One-year clinical events (all-cause death or cardiovascular hospitalization or emergency department visit) were ascertained. We used generalized linear modeling to quantify associations between physical frailty and HRQOL, and Cox proportional hazards modeling to quantify associations between physical frailty and clinical events, adjusting for Seattle HF Model scores.

RESULTS

The sample (n = 115) was 63.5 ± 15.7 years old and 49% women. Physical frailty was associated with significantly worse total HRQOL among women (p = 0.005) but not men (p = 0.141). Physical frailty was associated with worse physical HRQOL among both women (p < 0.001) and men (p = 0.043). There was a 46% higher clinical event risk for every one-point increase in physical frailty score among men (p = 0.047) but not women (p = 0.361).

CONCLUSIONS

Physical frailty is associated with worse overall HRQOL among women and higher clinical event risk among men, indicating a need to better understand contributors to sex-specific health differences associated with physical frailty in HF.

Using Continuous Passive Assessment Technology to Describe Health and Behavior Patterns Preceding and Following a Cancer Diagnosis in Older Adults: Proof-of-Concept Case Series Study

BACKGROUND

Describing changes in health and behavior that precede and follow a sentinel health event, such as a cancer diagnosis, is challenging because of the lack of longitudinal, objective measurements that are collected frequently enough to capture varying trajectories of change leading up to and following the event. A continuous passive assessment system that continuously monitors older adults' physical activity, weight, medication-taking behavior, pain, health events, and mood could enable the identification of more specific health and behavior patterns leading up to a cancer diagnosis and whether and how patterns change thereafter.

OBJECTIVE

In this study, we conducted a proof-of-concept retrospective analysis, in which we identified new cancer diagnoses in older adults and compared trajectories of change in health and behaviors before and after cancer diagnosis.

METHODS

Participants were 10 older adults (mean age 71.8, SD 4.9 years; 3/10, 30% female) with various self-reported cancer types from a larger prospective cohort study of older adults. A technology-agnostic assessment platform using multiple devices provided continuous data on daily physical activity via wearable sensors (actigraphy); weight via a Wi-Fi-enabled digital scale; daily medication-taking behavior using electronic Bluetooth-enabled pillboxes; and weekly pain, health events, and mood with online, self-report surveys.

RESULTS

Longitudinal linear mixed-effects models revealed significant differences in the pre- and postcancer trajectories of step counts (P<.001), step count variability (P=.004), weight (P<.001), pain severity (P<.001), hospitalization or emergency room visits (P=.03), days away from home overnight (P=.01), and the number of pillbox door openings (P<.001). Over the year preceding a cancer diagnosis, there were gradual reductions in step counts and weight and gradual increases in pain severity, step count variability, hospitalization or emergency room visits, and days away from home overnight compared with 1 year after the cancer diagnosis. Across the year after the cancer diagnosis, there was a gradual increase in the number of pillbox door openings compared with 1 year before the cancer diagnosis. There was no significant trajectory change from the pre- to post-cancer diagnosis period in terms of low mood (P=.60) and loneliness (P=.22).

CONCLUSIONS

A home-based, technology-agnostic, and multidomain assessment platform could provide a unique approach to monitoring different types of behavior and health markers in parallel before and after a life-changing health event. Continuous passive monitoring that is ecologically valid, less prone to bias, and limits participant burden could greatly enhance research that aims to improve early detection efforts, clinical care, and outcomes for people with cancer.

Safety and tolerability of Pau d' Arco (Tabebuia avellanedae) for primary dysmenorrhea: A single-arm, open-label trial on adults ages 18-45

Objectives

To evaluate the safety and tolerability of encapsulated Tabebuia avellanedae in generally healthy women aged 18-45 with primary dysmenorrhea.

Methods

A single arm, open-label trial was conducted in which 1050 mg/day of encapsulated Tabebuia avellanedae (Pau d'Arco) was administered to twelve healthy women aged 18-45 for eight weeks. The primary outcome was safety and tolerability as measured by standardized adverse events scales and serial collection of laboratory markers to assess general health, prothrombin times, and the presence or absence of anemia. Secondary outcomes included pain intensity, quality of life, and pain interference measured by the Visual Analog Scale (VAS), the Patient-Reported Outcomes Measurement Information System (PROMIS) 29 survey, and the PROMIS Visual Sexual Function and Satisfaction: Interfering Factors survey, respectively. Exploratory outcomes included serum concentration of high-sensitivity C-reactive protein as a marker of systemic inflammation.

Results

Seventy-five percent of participants (n = 9/12) completed the study. Seventy-five percent of study participants (n = 9/12) reported an adverse event, most of which were characterized as mild, and none were determined to be a Food and Drug Administration (FDA) serious adverse event. Most laboratory markers stayed within normal limits throughout the study period with a few clinically mild abnormalities. There was a significant decrease in pain intensity compared to baseline after the first dose (p < .01), after 4 weeks of treatment (p < .01), and after 8 weeks of treatment (p < .01). Over the 8-week intervention period, pain interference, quality of life, and sexual function and satisfaction scores improved nonsignificantly and hs-CRP decreased nonsignificantly.

Conclusions

Tabebuia avellanedae supplementation of 1050 mg/day dose for eight weeks in generally healthy women aged 18-45 with primary dysmenorrhea was generally safe, associated with moderate tolerability, and associated with significant improvements in pain intensity scores. Future studies examining the safety and efficacy of Tabebuia avellanedae on primary dysmenorrhea are warranted.

Characteristics of prostate cancer survivors exposed to ADT and enrolled in a fall prevention exercise trial: Comparison of men with confirmed fall history to men with fall risk factors

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Background: Androgen deprivation therapy (ADT) for prostate cancer may result in accelerated aging that increases the risk for falls. Falls are higher in men with a history of ADT use, even if treatment is discontinued, compared to men never on ADT. Less is known, however, about the specific patient characteristics that might be associated with falls. Methods: We analyzed data from prostate cancer survivors with a history of ADT and who had enrolled in an ongoing NIH-funded fall prevention exercise trial (NCT03741335). To be eligible for the trial, men were 1) currently or previously treated with ADT and 2) reported a fall in the previous 6 months or had evidence of fall risk. Fall risk was assessed through slow times on a 5 time sit-to-stand test (5XSTS; sec) or timed up and go walk test (TUG; sec). For this analysis we compared men with a positive fall history to men with no recent falls but evidence of fall risk. We compared age, ADT history (past vs current), body mass index (BMI), self-report comorbidities from the Charlson Comorbidity Index, physical function and disability from the LLFDI, pain from the BPI, anxiety from PROMIS, depressive symptoms from the CES-D, fear of falling and activity restrictions from the SAFFE, and physical activity from CHAMPS, as well as objective measures of strength and mobility using 5XSTS and TUG. Results: A total of 171 cases (mean age 73.1 +/- 7.1 years of age) were available for analysis, with 58 men (34%) reporting a fall in the 6 months prior to enrollment. Of reported falls, 11% were injurious falls, with 4% requiring medical attention. Injuries included fractures (n = 4), head injury (n = 2), joint injury (n = 3), and bruises/scrapes (n = 8). Fallers reported significantly lower levels of physical functioning (p < 0.001), greater levels of disability (p < 0.01), greater fear of falling (p < 0.001), more activity restrictions due to falls worry (p < 0.02) and slower TUG times (p < 0.03), than men who had not recently fallen. There were no significant differences between men with established fall history and men with fall risk only on age, ADT history, comorbidities, BMI, pain, anxiety, depressive symptoms, physical activity, or 5XSTS (p for all > 0.05). Conclusions: Among our preliminary sample of men with a history of ADT use and enrolled in an ongoing fall prevention trial, men with an established fall history functioned less independently, were more worried about falls and apt to restrict their activities accordingly, and had poorer mobility than men who hadn’t recently fallen. From our cross-sectional design we cannot determine whether poorer functioning and mobility and greater fear of falling were antecedents or consequences of a recent fall. Regardless, interventions designed to prevent falls in men exposed to ADT are critical to prevent potential injurious falls and to keep men functioning independently.

Qualitative Impressions of a Yoga Nidra Practice for Insomnia: An Exploratory Mixed-Methods Design

Introduction: Insomnia affects up to half of the U.S. population, and due to limitations of current treatments, there is a growing interest in mind-body practices to reduce insomnia. To understand how a guided meditation practice, Yoga Nidra, may affect relaxation and align with current descriptions of nonpharmaceutical practices that could improve sleep, qualitative and quantitative methods were used to explore participant experience of a single Yoga Nidra practice, administered in a group setting. Methods: Current insomnia (Insomnia Severity Index), sleep practices, and mood (positive and negative affect schedule [PANAS]) were measured at intake. After 30 min of Yoga Nidra practice, the PANAS was readministered. In a focus group that followed, participants discussed their experience before, during, and after the practice and the likelihood of repeating it. Six groups were conducted. All interested adults were welcome to join. Results: In the final sample of 33 individuals (79% female), 80% of participants reported insomnia at intake and 45% reported a regular mind-body practice, supporting the prevalence of insomnia in the society as well as the interest in mind-body practices. After the Yoga Nidra intervention, mean negative affect decreased 5.6 ± 4.5 points, a 31% decrease from baseline, and positive affect decreased 3.5 ± 9.7 points, a 13% decrease. Three major themes were identified from focus group discussions: response to the practice (relaxation, perceived sleep, and sense withdrawal); factors that affect engagement (delivery method and intrapersonal factors); and potential as a clinical intervention (for conditions including sleep, anxiety, and pain). Conclusion: Yoga Nidra appeared tolerable within the sample, and descriptions suggest it may be useful for enhancing relaxation, facilitating sleep, easing anxiety, and reducing pain. Results from this study will inform the design of future studies of Yoga Nidra for insomnia and related conditions.

Effects of Hydrastis Canadensis, Commiphora Habessinica, Phytolacca Americana, and Echinacea Purpurea on Bacterial Growth

CONTEXT

With the rise of antibiotic resistance, new strategies are needed to treat minor bacterial infections so that conventional antibiotics may be reserved for more serious conditions. One herbal formula, known as the HMPE formula, is often prescribed for minor infections. It includes Hydrastis canadensis (H. canadensis), Commiphora habessinica (C. habessinica), Phytolacca americana (P. americana), and Echinacea purpurea (E. purpurea). These herbs offer promise as treatments that may inhibit bacterial growth and stimulate the immune system.

OBJECTIVE

To investigate the antibacterial effects of the HMPE formula and its constituent herbs against two organisms, Staphylococcus epidermidis and Escherichia coli.

DESIGN

The research team performed an in-vitro study.

SETTING

The study occurred at the Helfgott Research Institute at the National University of Natural Medicine in Portland, OR, USA.

INTERVENTION

The study tested HMPE and each of its ingredients alone for antibacterial properties.

OUTCOME MEASURES

The outcome measure was a disc diffusion assay. Sterile paper discs were impregnated with 15 µl of E. purpurea, H. canadensis, C. habessinica , or P. americana as herbal tinctures; with the complete HMPE formula; or with 65% ethanol as the negative control, and dried at room temperature for 40 minutes. Commercially prepared 10 µg ampicillin discs were used as a positive control.

RESULTS

H. Canadensis and, to a lesser extent, the complete HMPE formula significantly inhibited the growth of the gram-positive bacteria Staphylococcus epidermidis, but not the gram-negative bacteria Escherichia coli. C. habessinica, P. americana, and E. purpurea alone did not inhibit growth of either bacterial strain.

CONCLUSIONS

The results demonstrated that H. canadensis had antibacterial activity against S. epidermidis, but the HMPE formula was not active against S. epidermidis, when a zone of inhibition threshold of 12 millimeters (mm) was used to determine antibiotic activity. Because the HMPE formula was shown to be less effective than H. canadensis alone, the formula might benefit from an increased percentage of H. canadensis.

Continuous unobtrusive assessment of meaningful change in older adults with cancer: The Pacific Aging & Cancer Study Collaborative—PACS collaborative

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Background: Knowledge of changes in health that precede a cancer diagnosis is challenging because of a lack of longitudinal, objective measurement techniques. Current approaches rely on periodic assessment via self-report which may miss when and how health changes, particularly when changes may appear subtly over time. Remote-monitoring technologies provide a mechanism to continuously, passively, and unobtrusively monitor changes in health so that trajectories of change in relation to a life event (i.e., cancer diagnosis, treatment) can be detected and described. We examined the changes in digital indicators of health and life events 1 year before and after a self-reported cancer diagnosis in community-dwelling adults aged 65 and older. Methods: This is a secondary, retrospective data analysis of older adults who self-reported a new cancer diagnosis in the Oregon Center for Aging & Technology (ORCATECH) cohort. Ten older adults (age = 71.8±4.9 years, 30% women) were included with various cancer types (esophageal, prostate, uterine, pancreatic, b-cell follicular lymphoma, multiple myeloma, basal cell melanoma, basal and/or squamous cell carcinoma). Daily physical activity was measured using step counts derived from an actigraph watch. Weekly health and life events (pain severity, loneliness, hospitalization/emergency room (ER) visits, days away from home overnight) were self-reported from weekly online surveys. Results: A total of 3,624 days of actigraphy data (210 ± 88 days pre-cancer; 153 ± 81 days post-cancer) and 750 weeks of self-reported online survey data (36 ± 12 weeks pre-cancer; 39 ± 14 weeks post-cancer) were collected. Longitudinal linear mixed-effects models revealed that the trajectory of step counts was different pre- and post-cancer (β = -1.52, p <.001), with a gradual decrease in step counts before a cancer diagnosis. The trajectory of pain severity was different pre- and post-cancer (β = 0.01, p <.001), with a gradual increase in pain severity before a cancer diagnosis. There was a gradual increase in the occurrence of hospitalization/ER visits (OR = 1.07, p = 0.02) and days away from home overnight (OR = 1.04, p = 0.01) before a cancer diagnosis. Feelings of loneliness increased over time, regardless of pre- or post-cancer (OR = 1.04, p <.001). Conclusions: Changes in health and life events 1-year before a cancer diagnosis in older adults with varying cancer types and severity were unobtrusively observed. This study suggests that a remote-monitoring technology platform deployed in homes can detect meaningful intra-individual changes before and after a cancer diagnosis. Future studies can employ this technology as a pathway for improving the timeliness of detection and more effective therapeutic follow-up for older adults.

Predictors of falls after starting an exercise program: A secondary analysis in inactive, female cancer survivors participating in the GET FIT trial

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Background: Women treated for cancer are more likely to fall than women without a cancer history. Exercise is a fall prevention strategy for older adults that we are testing in the GET FIT trial as a fall prevention approach in women cancer survivors. Increasing physical activity, though, could acutely increase the risk of falls in inactive survivors with known fall risk related to treatment. Knowing who might be at risk prior to beginning an exercise program would inform additional safety precautions during exercise. Methods: We conducted a secondary analysis of baseline data from the GET FIT trial that enrolled inactive, older women who had completed chemotherapy for cancer. Women completed objective (muscle strength, static postural control, range of motion, physical functioning) and self-report (fall history, comorbidities, presence of neuropathy symptoms, pain severity, depressive symptoms, cognitive functioning, perceptions of lower extremity functioning, disability, fear of falling, demographic, and clinical characteristics) measures at baseline. Falls were prospectively collected during the 6 month intervention using monthly self report. Potential predictors of falls were included if univariate tests revealed significant differences between fallers and non-fallers. To identify the strongest predictors of falls, we used an automated model selection and multimodel inference approach to perform an exhaustive model search. Results: Baseline data were available for 415 participants with known faller status at the end of the intervention, of whom 31.3% (n = 130) reported at least one fall. The average age of the sample was 62.1±6.4 years and consisted mostly of non-Hispanic white, married, highly educated, overweight or obese women treated for breast cancer. Fallers (1+ falls) and non-fallers significantly differed on measures of fall history, comorbidities, pain, neuropathy, fear of falling, disability, perceived lower extremity functioning, cognitive functioning, depression, and postural control. The best model of faller status (per BIC) included postural control (p = 0.004), perceived lower extremity functioning (p = 0.072), and fear of falling (p = 0.030). Odds of ≥1 fall during the intervention increased by 1.72 (95% CI: 1.05-2.83) times for a 0.1-point decrease in postural control, 1.11 (1.04-1.19) times for a 0.1-point increase in fear of falling, and 1.02 (1.00-1.03) times for a 1-point decrease in perceived lower extremity functioning. Conclusions: Women cancer survivors with poor balance, poor self-rated functioning, and a fear of falling may need to take additional fall precautions when starting an exercise program. Clinical trial information: NCT01635413.

Combined targeting of SET and tyrosine kinases provides an effective therapeutic approach in human T-cell acute lymphoblastic leukemia

Recent evidence suggests that inhibition of protein phosphatase 2A (PP2A) tumor suppressor activity via the SET oncoprotein contributes to the pathogenesis of various cancers. Here we demonstrate that both SET and c-MYC expression are frequently elevated in T-ALL cell lines and primary samples compared to healthy T cells. Treatment of T-ALL cells with the SET antagonist OP449 restored the activity of PP2A and reduced SET interaction with the PP2A catalytic subunit, resulting in a decrease in cell viability and c-MYC expression in a dose-dependent manner. Since a tight balance between phosphatases and kinases is required for the growth of both normal and malignant cells, we sought to identify a kinase inhibitor that would synergize with SET antagonism. We tested various T-ALL cell lines against a small-molecule inhibitor screen of 66 compounds targeting two-thirds of the tyrosine kinome and found that combined treatment of T-ALL cells with dovitinib, an orally active multi-targeted small-molecule receptor tyrosine kinase inhibitor, and OP449 synergistically reduced the viability of all tested T-ALL cell lines. Mechanistically, combined treatment with OP449 and dovitinib decreased total and phospho c-MYC levels and reduced ERK1/2, AKT, and p70S6 kinase activity in both NOTCH-dependent and independent T-ALL cell lines. Overall, these results suggest that combined targeting of tyrosine kinases and activation of serine/threonine phosphatases may offer novel therapeutic strategies for the treatment of T-ALL.

Effects of Methylsulfonylmethane (MSM) on exercise-induced oxidative stress, muscle damage, and pain following a half-marathon: a double-blind, randomized, placebo-controlled trial

Background

Oxidative stress and muscle damage occur during exhaustive bouts of exercise, and many runners report pain and soreness as major influences on changes or breaks in training regimens, creating a barrier to training persistence. Methylsulfonylmethane (MSM) is a sulfur-based nutritional supplement that is purported to have pain and inflammation-reducing effects. To investigate the effects of MSM in attenuating damage associated with physical exertion, this randomized, double-blind, placebo-controlled study evaluated the effects of MSM supplementation on exercise-induced pain, oxidative stress and muscle damage.

Methods

Twenty-two healthy females (n = 17) and males (n = 5) (age 33.7 ± 6.9 yrs.) were recruited from the 2014 Portland Half-Marathon registrant pool. Participants were randomized to take either MSM (OptiMSM®) (n = 11), or a placebo (n = 11) at 3 g/day for 21 days prior to the race and for two days after (23 total). Participants provided blood samples for measurement of markers of oxidative stress, and completed VAS surveys for pain approximately one month prior to the race (T₀), and at 15 min (T₁), 90 min (T₂), 1 Day (T₃), and 2 days (T₄) after race finish. The primary outcome measure 8-hydroxy-2-deoxyguanine (8-OHdG) measured oxidative stress. Secondary outcomes included malondialdehyde (MDA) for oxidative stress, creatine kinase (CK) and lactate dehydrogenase (LDH) as measures of muscle damage, and muscle (MP) and joint pain (JP) recorded using a 100 mm Visual Analogue Scale (VAS). Data were analyzed using repeated and multivariate ANOVAs, and simple contrasts compared post-race time points to baseline, presented as mean (SD) or mean change (95% CI) where appropriate.

Results

Running a half-marathon induced significant increases in all outcome measures (p < 0.001). From baseline, 8-OHdG increased significantly at T₁ by 1.53 ng/mL (0.86–2.20 ng/mL CI, p < 0.001) and T₂ by 1.19 ng/mL (0.37–2.01 ng/mL CI, p < 0.01), and fell below baseline levels at T₃ by −0.46 ng/mL (−1.18–0.26 CI, p > 0.05) and T₄ by −0.57 ng/mL (−1.27–0.13 CI, p > 0.05). MDA increased significantly at T₁ by 7.3 μM (3.9–10.7 CI, p < 0.001). Muscle damage markers CK and LDH saw significant increases from baseline at all time-points (p < 0.01). Muscle and joint pain increased significantly from baseline at T₁, T₂, and T₃ (p < 0.01) and returned to baseline levels at T₄. Time-by-treatment results did not reach statistical significance for any outcome measure, however, the MSM group saw clinically significant (Δ > 10 mm) reductions in both muscle and joint pain.

Conclusion

Participation in a half-marathon was associated with increased markers of oxidative stress, muscle damage, and pain. MSM supplementation was not associated with a decrease from pre-training levels of oxidative stress or muscle damage associated with an acute bout of exercise. MSM supplementation attenuated post-exercise muscle and joint pain at clinically, but not statistically significant levels.

Curriculum Development of a Research Laboratory Methodology Course for Complementary and Integrative Medicine Students

Training in fundamental laboratory methodologies is valuable to medical students because it enables them to understand the published literature, critically evaluate clinical studies, and make informed decisions regarding patient care. It also prepares them for research opportunities that may complement their medical practice. The National College of Natural Medicine's (NCNM) Master of Science in Integrative Medicine Research (MSiMR) program has developed an Introduction to Laboratory Methods course. The objective of the course it to train clinical students how to perform basic laboratory skills, analyze and manage data, and judiciously assess biomedical studies. Here we describe the course development and implementation as it applies to complementary and integrative medicine students.

The Axin1 scaffold protein promotes formation of a degradation complex for c-Myc

Expression of the c-Myc proto-oncoprotein is tightly regulated in normal cells. Phosphorylation at two conserved residues, threonine58 (T58) and serine62 (S62), regulates c-Myc protein stability. In cancer cells, c-Myc can become aberrantly stabilized associated with altered T58 and S62 phosphorylation. A complex signalling cascade involving GSK3beta kinase, the Pin1 prolyl isomerase, and the PP2A-B56alpha phosphatase controls phosphorylation at these sites. We report here a novel role for the tumour suppressor scaffold protein Axin1 in facilitating the formation of a degradation complex for c-Myc containing GSK3beta, Pin1, and PP2A-B56alpha. Although knockdown of Axin1 decreases the association of c-Myc with these proteins, reduces T58 and enhances S62 phosphorylation, and increases c-Myc stability, acute expression of Axin1 reduces c-Myc levels and suppresses c-Myc transcriptional activity. Moreover, the regulation of c-Myc by Axin1 is impaired in several tested cancer cell lines with known stabilization of c-Myc or loss of Axin1. This study provides critical insight into the regulation of c-Myc expression, how this can be disrupted in three cancer types, and adds to our knowledge of the tumour suppressor activity of Axin1.

FBW7 mutations in leukemic cells mediate NOTCH pathway activation and resistance to gamma-secretase inhibitors

γ-secretase inhibitors (GSIs) can block NOTCH receptor signaling in vitro and therefore offer an attractive targeted therapy for tumors dependent on deregulated NOTCH activity. To clarify the basis for GSI resistance in T cell acute lymphoblastic leukemia (T-ALL), we studied T-ALL cell lines with constitutive expression of the NOTCH intracellular domain (NICD), but that lacked C-terminal truncating mutations in NOTCH1. Each of the seven cell lines examined and 7 of 81 (8.6%) primary T-ALL samples harbored either a mutation or homozygous deletion of the gene FBW7, a ubiquitin ligase implicated in NICD turnover. Indeed, we show that FBW7 mutants cannot bind to the NICD and define the phosphodegron region of the NICD required for FBW7 binding. Although the mutant forms of FBW7 were still able to bind to MYC, they do not target it for degradation, suggesting that stabilization of both NICD and its principle downstream target, MYC, may contribute to transformation in leukemias with FBW7 mutations. In addition, we show that all seven leukemic cell lines with FBW7 mutations were resistant to the MRK-003 GSI. Most of these resistant lines also failed to down-regulate the mRNA levels of the NOTCH targets MYC and DELTEX1 after treatment with MRK-003, implying that residual NOTCH signaling in T-ALLs with FBW7 mutations contributes to GSI resistance.

Aberrant stabilization of c-Myc protein in some lymphoblastic leukemias

Overexpression of the c-Myc oncoprotein is observed in a large number of hematopoietic malignancies, and transgenic animal models have revealed a potent role for c-Myc in the generation of leukemias and lymphomas. However, the reason for high c-Myc protein levels in most cases is unknown. We examined whether aberrant protein stabilization could be a mechanism of c-Myc overexpression in leukemia cell lines and in primary bone marrow samples from pediatric acute lymphoblastic leukemia (ALL) patients. We found that c-Myc protein half-life was prolonged in the majority of leukemia cell lines and bone marrow samples tested. There were no mutations in the c-myc gene in any of the leukemia cell lines that could account for increased c-Myc stability. However, abnormal phosphorylation at two conserved sites, Threonine 58 and Serine 62, was observed in leukemia cell lines with stabilized c-Myc. Moreover, stabilized c-Myc from the ALL cell lines showed decreased affinity for glycogen synthase kinase3beta, the kinase that phosphorylates c-Myc at Threonine 58 and facilitates its degradation. These findings reveal that deregulation of the c-Myc degradation pathway controlled by Serine 62 and Threonine 58 phosphorylation is a novel mechanism for increased expression of a potent oncoprotein known to be involved in hematopoietic malignancies.

Uniform Adherent Neural Progenitor Populations from Rhesus Embryonic Stem Cells

Rhesus and human embryonic stem cells (ESCs) are similar, making rhesus ESCs an appropriate preclinical allograft model for refining stem cell therapies. Use of rhesus ESC-derived neural progenitors (NPs) in preclinical applications will be enhanced if the neural derivation process is scalable and free from contaminating ESCs or nonneural cells. In this study, we have quantified temporal gene expression changes of rhesus ESC differentiated to uniform NPs using simple feeder-free adherent cultures. NPs exhibited a significant up-regulation of neural-specific genes and a downregulation of pluripotency genes. Additionally, expression of Hu, MAP2, and Tuj1, shows that NPs can form post-mitotic neurons. This study represents a simple and scalable means of producing adherent primate NPs for preclinical testing of neural cell-based therapy.

Long-Term Proliferation of Human Embryonic Stem Cell-Derived Neuroepithelial Cells Using Defined Adherent Culture Conditions

Research on the cell fate determination of embryonic stem cells is of enormous interest given the therapeutic potential in regenerative cell therapy. Human embryonic stem cells (hESCs) have the ability to renew themselves and differentiate into all three germ layers. The main focus of this study was to examine factors affecting derivation and further proliferation of multipotent neuroepithelial (NEP) cells from hESCs. hESCs cultured in serum-deprived defined medium developed distinct tube structures and could be isolated either by dissociation or adherently. Dissociated cells survived to form colonies of cells characterized as NEP when conditioned medium from human hepatocellular carcinoma HepG2 cell line (MEDII) was added. However, cells isolated adherently developed an enriched population of NEP cells independent of MEDII medium. Further characterization suggested that they were NEP cells because they had a similar phenotype profile to in vivo NEP cells and expression SOX1, SOX2, and SOX3 genes. They were positive for Nestin, a neural intermediate filament protein, and Musashi-1, a neural RNA-binding protein, but few cells expressed further differentiation markers, such as PSNCAM, A2B5, MAPII, GFAP, or O4, or other lineage markers, such as muscle actin, alpha fetoprotein, or the pluripotent marker Oct4. Further differentiation of these putative NEP cells gave rise to a mixed population of progenitors that included A2B5-positive and PSNCAM-positive cells and postmitotic neurons and astrocytes. To proliferate and culture these derived NEP cells, ideal conditions were obtained using neurobasal medium supplemented with B27 and basic fibroblast growth factor in 5% oxygen. NEP cells were continuously propagated for longer than 6 months without losing their multipotent cell characteristics and maintained a stable chromosome number.