Understanding mechanisms of racial disparities in breast cancer: an assessment of screening and regular care in the Carolina Breast Cancer Study.

PURPOSE: Screening history influences stage at detection, but regular preventive care may also influence breast tumor diagnostic characteristics. Few studies have evaluated healthcare utilization (both screening and primary care) in racially diverse screening-eligible populations. METHODS: This analysis included 2,058 women age 45-74 (49% Black) from the Carolina Breast Cancer Study, a population-based cohort of women diagnosed with invasive breast cancer between 2008 and 2013. Screening history (threshold 0.5 mammograms per year) and pre-diagnostic healthcare utilization (i.e. regular care, based on responses to "During the past ten years, who did you usually see when you were sick or needed advice about your health?") were assessed as binary exposures. The relationship between healthcare utilization and tumor characteristics were evaluated overall and race-stratified. RESULTS: Among those lacking screening, Black participants had larger tumors (5 + cm) (frequency 19.6% vs 11.5%, relative frequency difference (RFD) = 8.1%, 95% CI 2.8-13.5), but race differences were attenuated among screening-adherent participants (10.2% vs 7.0%, RFD = 3.2%, 0.2-6.2). Similar trends were observed for tumor stage and mode of detection (mammogram vs lump). Among all participants, those lacking both screening and regular care had larger tumors (21% vs 8%, RR = 2.51, 1.76-3.56) and advanced (3B +) stage (19% vs 6%, RR = 3.15, 2.15-4.63) compared to the referent category (screening-adherent and regular care). Under-use of regular care and screening was more prevalent in socioeconomically disadvantaged areas of North Carolina. CONCLUSIONS: Access to regular care is an important safeguard for earlier detection. Our data suggest that health equity interventions should prioritize both primary care and screening.

Factors associated with HIV Testing within the National Health Interview Survey (2006-2018).

The Centers for Disease Control and Prevention recommends that individuals aged 13-64 test for HIV at least once during their lifetime. However, screening has been disproportionate among racial/ethnic populations. Using the National Health Interview Survey data (2006-2018), we examined HIV screening prevalence within racial/ethnic groups in the United States (US), and factors associated with testing among 301,191 individuals. This consisted of 195,696 White, 42,409 Black, 47,705 Hispanic and 15,381 Asian individuals. Logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI) to estimate the association between ever testing for HIV and demographic, socioeconomic and health-related factors. Approximately 36% of White, 61% of Black, 47% of Hispanic and 36% of Asian individuals reported ever testing for HIV. Hispanic (OR = 1.28, 95% CI [1.25-1.32]) and Black individuals (OR = 2.44, 95% CI [2.38-2.50]) had higher odds of HIV testing, whereas Asian individuals (OR = 0.74, 95% CI [0.71-0.77]) had lower odds of HIV testing compared to White individuals. Individuals who identified as males, married, between the ages of 18-26 years or greater than or equal to 50 years were less likely to ever test for HIV compared to their counterparts. Similarly, those with lower education, lower income, better self-reported health, no health professional visits or living in the midwestern US were less likely to ever test for HIV compared to their counterparts (OR range: 0.14-0.92). Understanding the factors associated with HIV testing opens opportunities to increase testing rates for all and reduce health disparities in HIV detection.

Body mass index and patient-reported function, quality of life and treatment toxicity in women receiving adjuvant chemotherapy for breast cancer.

BACKGROUND: This study investigates whether high body mass index (BMI) in women diagnosed with early breast cancer (BC) is associated with patient-reported symptom severity during chemotherapy. METHODS: Women with Stage I-III BC completed toxicity reports for 17 side effects throughout regularly scheduled chemotherapy infusions. Toxicity reports were compared in women with obesity (BMI > = 30) versus no obesity (BMI < 30). Fisher's exact tests and 2-sample t-tests compared baseline patient characteristics. Risk ratios (RR) for women with obesity as compared to no obesity were estimated for individual symptoms that were patient-rated as moderate, severe or very severe (MSVS) severity, adjusting for marital status and race. RESULTS: In a sample of 286 patients, Black women comprised 23% of the sample. The obesity rate was 76% among Black patients and 31% among White patients (p < .0001). Women with obesity rated an average of 6.9 side effects (standard deviation, SD 4.2) as MSVS vs 5.5 side effects (SD 3.7) among women with no obesity (p = .003). In adjusted analysis, women with obesity had significantly greater risk for MSVS fatigue (RR 1.18, 95% CI 1.01-1.36), dyspnea (RR 1.71, 95% CI 1.09-2.69), arthralgia (RR 1.47, 95% CI 1.10-1.97), peripheral neuropathy (RR 1.45, 95% CI 1.01-2.08), edema of limbs (RR 1.84, 95% CI 1.18-2.88), and abdominal pain (RR 1.75, 95% CI 1.07-2.87). There were no inter-group differences in BC stage or phenotype, chemotherapy treatment modifications, or hospitalizations. CONCLUSIONS: Among women with early BC, patients with obesity reported higher chemotherapy toxicity as compared to patients without obesity; however, this did not result in differences in treatment completion.

Prostate cancer aggressiveness and financial toxicity among prostate cancer patients.

INTRODUCTION: Financial toxicity (FT) is a growing concern among cancer survivors that adversely affects the quality of life and survival. Individuals diagnosed with aggressive cancers are often at a greater risk of experiencing FT. The objectives of this study were to estimate FT among prostate cancer (PCa) survivors after 10-15 years of diagnosis, assess the relationship between PCa aggressiveness at diagnosis and FT, and examine whether current cancer treatment status mediates the relationship between PCa aggressiveness and FT. METHODS: PCa patients enrolled in the North Carolina-Louisiana Prostate Cancer Project (PCaP) were recontacted for long-term follow-up. The prevalence of FT in the PCaP cohort was estimated. FT was estimated using the COmprehensive Score for Financial Toxicity, a validated measure of FT. The direct effect of PCa aggressiveness and an indirect effect through current cancer treatment on FT was examined using causal mediation analysis. RESULTS: More than one-third of PCa patients reported experiencing FT. PCa aggressiveness was significantly independently associated with high FT; high aggressive PCa at diagnosis had more than twice the risk of experiencing FT than those with low or intermediate aggressive PCa (adjusted odds ratio [aOR] = 2.13, 95% CI = 1.14-3.96). The proportion of the effect of PCa aggressiveness on FT, mediated by treatment status, was 10%, however, the adjusted odds ratio did not indicate significant evidence of mediation by treatment status (aOR = 1.05, 95% CI = 0.95-1.20). CONCLUSIONS: Aggressive PCa was associated with high FT. Future studies should collect more information about the characteristics of men with high FT and identify additional risk factors of FT.

Using health insurance claims data to assess long-term disease progression in a prostate cancer cohort.

BACKGROUND: Long-term population-based cohort studies of men diagnosed with prostate cancer are limited. However, adverse outcomes can occur many years after treatment. Herein, we aim to assess the utility of using claims data to identify prostate cancer progression 10-15 years after diagnosis. METHODS: The study population was derived from the North Carolina-Louisiana Prostate Cancer Project (PCaP). PCaP-North Carolina (NC) included 1031 men diagnosed with prostate cancer from 2004 to 2009. An initial follow-up with a survey and manual medical record abstraction occurred from 2008 to 2011 (Follow-up 1). Herein, we extended this follow-up with linkage to healthcare claims data from North Carolina (2011-2017) and a second, supplementary 10-year follow-up survey (2018-2020) (Follow-up 2). Vital statistics data also were utilized. Long-term oncological progression was determined using these data sources in combination with expert clinical input. RESULTS: Among the 1031 baseline PCaP-NC participants, 652 were linked to medical claims. Forty-two percent of the men had insurance coverage for the entire 72 months of follow-up. In addition, 275 baseline participants completed the supplementary 10-year follow-up survey. Using all sources of follow-up data, we identified a progression event in 259 of 1031 (25%) men with more than 10 years of follow-up data after diagnosis. CONCLUSIONS: Understanding long-term clinical outcomes is essential for improving the lives of prostate cancer survivors. However, access and utility of long-term clinical outcomes with claims alone remain a challenge due to individualized agreements required with each insurer for data access, lack of detailed clinical information, and gaps in insurance coverage. We were able to utilize claims data to determine long-term progression due to several unique advantages that included the availability of detailed baseline clinical characteristics and treatments, detailed manually abstracted clinical data at 5 years of follow-up, vital statistics data, and a supplementary 10-year follow-up survey.

Physical Function, Psychosocial Status, and Symptom Burden Among Adults with Plasma Cell Disorders and Associations with Quality of Life.

BACKGROUND: The plasma cell disorders (PCDs), multiple myeloma (MM), and light-chain amyloidosis (AL) are disproportionately diseases of older adults, whose care may be complicated by frailty associated with advancing age. We sought to evaluate the prevalence of functional deficits and symptoms in a cohort of persons with PCDs and associations of demographic, disease-related, functional, and psychosocial measures with quality of life (QoL). PATIENTS AND METHODS: Adults with PCDs were recruited into an observational registry in 2018-2020. Patients completed a functional assessment and European Organization for Research and Treatment of Cancer QoL questionnaire (QLQ-C30). Associations of covariates of interest with QoL were evaluated via univariate linear regression. RESULTS: Among 121 adults, the mean age was 68.6. Diagnoses were 74% MM, 14% AL, 7% both MM and AL, and 5% other PCDs. The median time from diagnosis was 34.9 months. Median lines of therapy were 2, with 11% having received ≥4th-line therapy.Patients with functional deficits had lower mean QoL scores: dependence in IADLs (66.3 vs. 79.9, P = .001) and recent falls (56.7 vs. 76.8, P = .001). Patients ≤6 months from diagnosis had lower QoL (66.7) than those ≥2 years from diagnosis (77.3, P = .03). However, patients on later lines of therapy (≥4th-line) had lower QoL (62.2) than those on 1st-line treatment (76.0, P = .04). CONCLUSIONS: Patients with physical impairments and more advanced PCDs had lower QoL than those without deficits or earlier in their disease course. Early identification of physical impairments may facilitate interventions that mitigate these deficits and thereby improve QoL for patients with PCDs.

Age and competing concerns in treatment selection for women with non-metastatic HR+ and HER2- breast cancer: Current clinical practice.

BACKGROUND: Newer adjuvant treatment options for non-metastatic breast cancer have increased survival. There is a need to investigate whether demographic and clinical characteristics of women with hormone receptor-positive, human epidermal growth receptor 2-negative non-metastatic breast cancer (stages I-III) differentially influence treatment decisions in older (age 65 or older) versus younger patients (under age 65). METHODS: In a retrospective electronic medical record review, prevalence ratio with 95% confidence interval for treatment decisions in older vs younger patients was calculated using log binomial regression adjusted for race, stage, and total number of comorbidities. RESULTS: In a sample of 537 patients, 66% were age < 65 and 34% age ≥ 65. Older patients included a higher proportion of White women (85% vs 75%, P = .02), higher number of comorbidities (P ≤0.0001), and lower stage tumors (P = .0004). In multivariable analysis, age ≥ 65 was independently associated with fewer mastectomies (95% CI 0.65-0.96, P = .02), more lumpectomies (95% CI 1.05-1.42, P = .01), and less receipt of radiation treatment (95% CI 0.78-0.97, P = .01) and/or chemotherapy (95% CI 0.73-0.95, P = .006). In multivariate analysis, stage was independently significant for all treatment modalities, except endocrine therapy, and race was not. CONCLUSIONS: This study suggests that age, in addition to breast cancer stage, is a predictor of treatment modality, independent of race and number of comorbidities. Treatment modality reflects a combination of patient preference and clinician assessment of fitness for current standard of care.

Prevalence and clinical correlates of cognitive impairment in adults with plasma cell disorders.

INTRODUCTION: Older adults with plasma cell disorders (PCDs) experience cognitive dysfunction that may be attributable to the disease and associated therapies. Yet, this has seldom been reported in the literature. Our objectives were to describe cognitive function (objective and patient-reported) in adults with PCDs and to explore clinical correlates of cognitive impairment. MATERIALS AND METHODS: Participants completed a geriatric assessment between March 2018 and February 2020. Cognitive function was evaluated using two objective measures - Montreal Cognitive Assessment (MoCA, cutpoint <26) and Blessed Orientation Memory Concentration Test (BOMC, cutpoint >4) - and two patient-reported outcome (PRO) measures - Patient-Reported Outcomes Measurement Information System Cognitive Function (PROMIS-CF, cutpoint <45) and European Organization for Research and Treatment of Cancer Cognitive Functioning subscale (EORTC-CF, cutpoint <75). Spearman correlations examined relationships among these measures and log binomial regression was used to examine characteristics associated with cognitive impairment, as defined by the MoCA and PROMIS-CF measures. RESULTS: Among 86 participants with a mean age of 69 (range: 46-91), the prevalence of cognitive dysfunction was between 20% (BOMC) and 63% (MoCA). There was moderate correlation among objective measures (r = 0.51, p < 0.0001), moderate to high correlation among PRO measures (r = 0.69, p < 0.0001), but no correlation between objective and PRO measures. Factors associated with objective impairment included ≤ high school education (RR 1.46, p = 0.009), living alone (RR 1.42, p = 0.02), relapsed/refractory disease (RR 1.39, p = 0.04), empirically de-intensified induction therapy (RR 1.62, p = 0.008), frailty (RR 1.49, p = 0.04), and peripheral vascular disease (RR 1.54, p = 0.002). Factors associated with PRO impairment included social isolation (RR 3.43, p = 0.003), depression (RR 3.30, p = 0.004) and anxiety (RR 4.43, p = 0.0002), frailty (RR 3.60, p = 0.02), falls in the previous 6 months (RR 2.53, p = 0.02), and deficits in physical function (RR 4.44, p = 0.01). Older age was not associated with either objective or PRO impairment. DISCUSSION: Cognitive impairment, using objective and PRO screening measures, was relatively common in adults with PCDs. Cancer-related factors and medical comorbidities were associated with objective cognitive impairment whereas psychosocial and functional factors were associated with PRO impairment.

Breast cancer treatment patterns by age and time since last pregnancy in the Carolina Breast Cancer Study Phase III.

PURPOSE: To describe breast cancer treatment patterns among premenopausal women by age and time since last pregnancy. METHODS: Data were analyzed from 1179 women diagnosed with premenopausal breast cancer in the Carolina Breast Cancer Study. Of these, 160 had a recent pregnancy (within 5 years of cancer diagnosis). Relative frequency differences (RFDs) and 95% confidence intervals (CIs) were used to compare cancer stage, treatment modality received, treatment initiation delay (> 30 days), and prolonged treatment duration (> 2 to > 8 months depending on the treatment received) by age and recency of pregnancy. RESULTS: Recently postpartum women were significantly more likely to have stage III disease [RFD (95% CI) 12.2% (3.6%, 20.8%)] and to receive more aggressive treatment compared to nulliparous women. After adjustment for age, race and standard clinical tumor characteristics, recently postpartum women were significantly less likely to have delayed treatment initiation [RFD (95% CI) - 11.2% (- 21.4%, - 1.0%)] and prolonged treatment duration [RFD (95% CI) - 17.5% (- 28.0%, - 7.1%)] and were more likely to have mastectomy [RFD (95% CI) 14.9% (4.8%, 25.0%)] compared to nulliparous. Similarly, younger women (< 40 years of age) were significantly less likely to experience prolonged treatment duration [RFD (95% CI) - 5.6% (- 11.1%, - 0.0%)] and more likely to undergo mastectomy [RFD (95% CI) 10.6% (5.2%, 16.0%)] compared to the study population as a whole. CONCLUSION: These results suggest that recently postpartum and younger women often received prompt and aggressive breast cancer treatment. Higher mortality and recurrence among recently pregnant women are unlikely to be related to undertreatment.

Phase Ib trial of lenalidomide as post-remission therapy for older adults with acute myeloid leukemia: Safety and longitudinal assessment of geriatric functional domains.

BACKGROUND AND OBJECTIVES: Novel, non-cytotoxic agents are driving a paradigm shift for treatment of older adults with acute myeloid leukemia (AML). Older patients who initially receive intensive cytotoxic induction may choose to not proceed with cytotoxic consolidation therapy. Lenalidomide is an orally-administered immunomodulatory small molecule with activity in AML and a favorable safety profile in older adults with active leukemia. We conducted a phase Ib study of lenalidomide as post-remission therapy in older adults and assessed its impact on geriatric functional domains. MATERIALS AND METHODS: Participants were patients with AML over age 60 years who had undergone induction therapy and were poor candidates for cytotoxic consolidation. Lenalidomide was administered for 28 days in three dose cohorts. A Bayesian dose-escalation method determined cohort assignment and maximum tolerated dose (MTD). Geriatric assessment (GA) was performed before and after the cycle of lenalidomide. RESULTS: Nineteen patients with median age 68 were treated with at least one 28-day course of lenalidomide. Dose-limiting toxicities were observed in three participants at 25 mg, zero participants at 35 mg, and one participant at 50 mg. MTD was 35 mg. Median relapse-free survival was 4.3 months. GA was completed before and after treatment in fifteen patients, demonstrating improved cognitive function and no changes in physical, psychological, or social function after lenalidomide. CONCLUSION: Lenalidomide can be safely administered to older adults with AML with preservation of functional domains important to older patients. Serial GA can be performed in a novel drug study as a tool to characterize treatment tolerability.

Geriatric-assessment-identified functional deficits among adults with multiple myeloma with normal performance status.

OBJECTIVES: Findings from a brief geriatric assessment (GA) in a cohort of adults with multiple myeloma (MM) are presented, with particular attention to the utility of the GA in identifying important deficits in adults judged to have a normal Karnofsky Performance Status (KPS ≥ 80). MATERIALS AND METHODS: Adults age 18 and older with MM were recruited into an observational study from 2018 to 2020. A modified Cancer and Aging Research Group (CARG) GA was administered at enrollment. Enrollees also completed the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life of Cancer Patients Core 30 questionnaire (QLQ-C30), with subscales of physical, social, role, and cognitive functioning (range 0-100; higher values indicate better function). Data were analyzed using descriptive statistics for the full cohort and stratified by concurrent KPS (score < 80 vs ≥ 80). RESULTS: Among 89 adults, the mean age was 69.1 years, 68% were aged ≥65 years, and 70% were white. In this cohort, 78% had KPS ≥ 80. Among those with KPS ≥ 80, functional impairments (Timed Up and Go ≥14 s and dependence in ≥1 instrumental activity of daily living) were seen in 30% and 21%, respectively, with 11% reporting ≥1 fall in the prior 6 months. At least two GA-identified deficits were detected in 50% of the overall cohort and in 41% of those with KPS ≥ 80. Among those with KPS ≥ 80, self-reported physical impairment on EORTC QLQ-C30 was noted by 34%. CONCLUSION: Using a modified CARG GA and EORTC questionnaire, functional impairments were identified among adults considered to have a good performance status based on a KPS (≥ 80). Future studies should focus on using GA measures for therapy assignment and identifying opportunities for intervening upon GA-identified deficits.

Molecular and Clinical Characterization of Postpartum-Associated Breast Cancer in the Carolina Breast Cancer Study Phase I-III, 1993-2013.

BACKGROUND: Breast cancers in recently postpartum women may have worse outcomes, but studies examining tumor molecular features by pregnancy recency have shown conflicting results. METHODS: This analysis used Carolina Breast Cancer Study data to examine clinical and molecular tumor features among women less than 50 years of age who were recently (≤10 years prior) or remotely (>10 years prior) postpartum, or nulliparous. Prevalence odds ratios (POR) and 95% confidence intervals (CI) were estimated using multivariable models. RESULTS: Recently postpartum women (N = 618) were more frequently lymph node-positive [POR (95% CI): 1.66 (1.26-2.19)], estrogen receptor (ER)-negative [1.37 (1.02-1.83)], and IHC-based triple negative [1.57 (1.00-2.47)] compared with nulliparous (N = 360) women. Some differences were identified between recent versus remotely postpartum; smaller tumor size [0.67 (0.52-0.86)], p53 wildtype [0.53 (0.36-0.77)], and non-basal-like phenotype [0.53 (0.33-0.84)] were more common among recently postpartum. Recently postpartum (vs. nulliparous) had significant enrichment for adaptive immunity, T cells, B cells, CD8 T cells, activated CD8 T cells/natural killer (NK) cells, and T follicular helper (Tfh) cells and higher overall immune cell scores. These differences were attenuated in remotely (compared with recently) postpartum women. CONCLUSIONS: These results suggest a dominant effect of parity (vs. nulliparity) and a lesser effect of pregnancy recency on tumor molecular features, although tumor immune microenvironments were altered in association with pregnancy recency. IMPACT: Our study is unique in examining tumor immune microenvironment and RNA-based markers according to time since last childbirth. Future studies should examine the interplay between tumor features, postdiagnostic treatment, and outcomes among recently postpartum women. See related commentary by McDonald et al., p. 518.

Genetically Engineered Human Kidney Cells for Real-Time Cytotoxicity Testing In Vitro.

Classic toxicology studies often utilize in vivo animal models. Newer approaches employing in vitro organ-specific cellular models have been developed in recent years to help accelerate the speed and reduce the cost of traditional toxicology testing. Toward the goal of supporting in vitro cellular model research with a regulatory application in mind, we have developed a 'designer' human kidney cell line called HK2-Vi that can fluorescently measure the cytotoxicity of potential toxins on proximal tubule cell viability in a direct exposure in vitro model. HK2-Vi was designed to be a reagent-less kinetic assay that can yield data on short- or long-term cell viability after toxin exposure. To generate HK2-Vi, we used monocistronic lentiviral transduction methods to genetically engineer a human kidney cell line called HK-2 to stably co-express two transgenes. The first is Perceval HR, which encodes a fluorescent biosensor of both cytosolic ATP and ADP and the second is pHRed, which encodes a biosensor of cytosolic pH. Relative levels of cellular ATP and ADP effectively serve as a reliable and robust indicator of cell viability. Because the fluorescence Perceval HR is pH-dependent, we co-expressed the pHRed genetic biosensor to correct for variations in pH if necessary. Heterogenous populations of transduced renal cells were enriched by flow cytometry before monoclonal cellular populations were isolated by cell culture methods. A single clonal population of co-transduced cells expressing both Perceval HR and pHRed was selected to be HK2-Vi. This established cell line can now serve as a tool for in vitro toxicology testing and the methods described herein serve as a model for developing designer cell lines derived from other organs.

Reproductive and Hormonal Factors in Relation to Lung Cancer Among Nepali Women.

Background: Of the 1.8 million global incident lung cancer cases estimated in 2012, approximately 60% occurred in less developed regions. Prior studies suggest sex differences in lung cancer risk and a potential role for reproductive and hormonal factors in lung cancer among women. However, the majority of these studies were conducted in developed regions. No prior study has assessed these relationships among Nepali women. Methods: Using data from a hospital-based case-control study conducted in B. P. Koirala Memorial Cancer Hospital (Nepal, 2009-2012), relationships between reproductive and hormonal factors and lung cancer were examined among women aged 23-85 years. Lung cancer cases (n = 268) were frequency-matched to controls (n = 226) based on age (±5 years), ethnicity and residential area. The main exposures in this analysis included menopausal status, age at menarche, age at menopause, menstrual duration, gravidity, and age at first live-birth. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression. Results: Among postmenopausal women, those with a younger age at menopause (<45 years; 45-49 years) had an increased odds of lung cancer compared to those with an older (≥50 years) age at menopause [OR (95%CI): 2.14 (1.09, 4.17); OR (95% CI): 1.93 (1.07, 3.51)], after adjusting for age and cumulative active smoking years. No statistically significant associations were observed with the other reproductive and hormonal factors examined. Conclusion: These results suggest that Nepali women with prolonged exposure to endogenous ovarian hormones, via later age at menopause, may have a lower odds of lung cancer.

Diglycolic acid induces HepG2/C3A liver cell toxicity in vitro.

Carboxymethyl starches are added to food products for thickening or tablet binding/filling purposes. Although they lack toxicity, their synthesis creates the chemical byproduct diglycolic acid (DGA), which is difficult to eliminate and whose toxicity is in question. A rare case of an accidental direct exposure to extremely high concentrations of DGA in a person revealed that DGA has the potential to be toxic to several organs, with the kidneys and liver being the most affected organs. Given that DGA is present in our food supply as a chemical byproduct of carboxymethyl starch food additives, we sought to perform in vitro testing of its potential hepatotoxicity to help complement a recent in vivo rat acute dose-response study that also tested for the potential hepatotoxic effects of daily DGA ingestion by oral gavage over a period of 28 days. Using the HepG2/C3A cellular in vitro model, we tested how escalating doses of DGA exposure over 24 h could induce hepatotoxicity. Both in vitro and in vivo testing systems revealed that DGA is indeed a hepatotoxin once a certain exposure threshold is reached. The concordance of these models highlights the utility of in vitro testing to support and help predict in vivo findings.

Simultaneous determination of intestinal permeability and potential drug interactions of complex mixtures using Caco-2 cells and high-resolution mass spectrometry: Studies with Rauwolfia serpentina extract.

Caco-2 cells are a commonly used model for estimating the intestinal bioavailability of single chemical entity pharmaceuticals. Caco-2 cells, when induced with calcitriol, also express other biological functions such as phase I (CYP) and phase II (glucuronosyltransferases) drug metabolizing enzymes which are relevant to drug-supplement interactions. Intestinal bioavailability is an important factor in the overall safety assessment of products consumed orally. Foods, including herbal dietary supplements, are complex substances with multiple chemical components. Because of potential interactions between components of complex mixtures, more reliable safety assessments can be obtained by studying the commercial products "as consumed" rather than by testing individual chemical components one at a time. The present study evaluated the apparent intestinal permeability (Papp) of a model herbal extract, Rauwolfia serpentina, using both whole plant extracts and the individual purified Rauwolfia alkaloids. All test compounds, endpoint substrates, and their metabolites were quantified using liquid chromatography and high-resolution mass spectrometry. The Papp values for individual Rauwolfia alkaloids were comparable whether measured individually or as components of the complete extract. Both Rauwolfia extract and all individual Rauwolfia alkaloids except yohimbine inhibited CYP3A4 activity (midazolam 1'-hydroxylation). Both Rauwolfia extract and all individual Rauwolfia alkaloids except corynanthine and reserpic acid significantly increased glucuronosyltransferase activity (glucuronidation of 4-methylumbelliferone). The positive control, ketoconazole, significantly inhibited both CYP3A4 and glucuronosyltransferase activities. These findings suggest that the Caco-2 assay is capable of simultaneously identifying both bioavailability and potentially hazardous intestinal drug-supplement interactions in complex mixtures.

Comparison of diglycolic acid exposure to human proximal tubule cells in vitro and rat kidneys in vivo.

Diglycolic acid (DGA) is present in trace amounts in our food supply and is classified as an indirect food additive linked with the primary GRAS food additive carboxymethyl cellulose (CMC). Carboxymethyl starches are used as a filler/binder excipient in dietary supplement tablets and a thickening ingredient in many other processed foods. We sought to utilize the human proximal tubule HK-2 cell line as an in vitro cellular model system to evaluate its acute nephrotoxicity of DGA. We found that DGA was indeed toxic to HK-2 cells in all in vitro assays in our study, including a highly sensitive Luminex assay that measures levels of an in vitro biomarker of kidney-specific toxicity, Kidney Injury Molecule 1 (KIM-1). Interestingly, in vitro KIM-1 levels also correlated with in vivo KIM-1 levels in urine collected from rats treated with DGA by daily oral gavage. The use of in vitro and in vivo models towards understanding the effectiveness of an established in vitro system to predict in vivo outcomes would be particularly useful in rapidly screening compounds that are suspected to be unsafe to consumers. The merit of the HK-2 cell model in predicting human toxicity and accelerating the process of food toxicant screening would be especially important for regulatory purposes. Overall, our study not only revealed the value of HK-2 in vitro cell model for nephrotoxicity evaluation, but also uncovered some of the mechanistic aspects of the human proximal tubule injury that DGA may cause.

28-day repeated dose response study of diglycolic acid: Renal and hepatic effects.

The acute oral toxicity of diglycolic acid (DGA) was evaluated. Groups of female rats (n = 8 rats/group) received 28 consecutive daily single doses of 0.3, 1.0, 3.0, 10.0, 30.0, 100.0 or 300.0 mg DGA/kg body weight by gastric intubation. One group of animals served as vehicle control. Tissues and blood serum were collected at necropsy on day 29. Select organs were weighed and fixed in formalin for histopathological analysis. Animals from the 300 mg/kg bw dose group were removed from the study after 5 consecutive days of treatment as a consequence of adverse treatment related effects. The animals in the remaining treatment groups survived the exposure period. No adverse clinical signs were observed throughout the exposure period in the surviving animals. No significant differences from controls were observed for feed and fluid consumption or body weight gain in the surviving animals. Lesions were observed in the kidneys, liver, stomach, intestine, thymus, spleen and bone marrow in rats from the 300 mg/kg dose group and signs of renal tubular regeneration were observed only in the 100 mg/kg dose group. These results suggest that high levels of pure DGA would need to be consumed before renal and other forms of organ toxicity are observed.

Evaluation of "Dream Herb," Calea zacatechichi, for Nephrotoxicity Using Human Kidney Proximal Tubule Cells.

A recent surge in the use of dietary supplements, including herbal remedies, necessitates investigations into their safety profiles. "Dream herb," Calea zacatechichi, has long been used in traditional folk medicine for a variety of purposes and is currently being marketed in the US for medicinal purposes, including diabetes treatment. Despite the inherent vulnerability of the renal system to xenobiotic toxicity, there is a lack of safety studies on the nephrotoxic potential of this herb. Additionally, the high frequency of diabetes-associated kidney disease makes safety screening of C. zacatechichi for safety especially important. We exposed human proximal tubule HK-2 cells to increasing doses of this herb alongside known toxicant and protectant control compounds to examine potential toxicity effects of C. zacatechichi relative to control compounds. We evaluated both cellular and mitochondrial functional changes related to toxicity of this dietary supplement and found that even at low doses evidence of cellular toxicity was significant. Moreover, these findings correlated with significantly elevated levels of nephrotoxicity biomarkers, lending further support for the need to further scrutinize the safety of this herbal dietary supplement.

The local expression and trafficking of tyrosine hydroxylase mRNA in the axons of sympathetic neurons.

Synthesis and regulation of catecholamine neurotransmitters in the central nervous system are implicated in the pathogenesis of a number of neuropsychiatric disorders. To identify factors that regulate the presynaptic synthesis of catecholamines, we tested the hypothesis that the rate-limiting enzyme of the catecholamine biosynthetic pathway, tyrosine hydroxylase (TH), is locally synthesized in axons and presynaptic nerve terminals of noradrenergic neurons. To isolate pure axonal mRNA and protein, rat superior cervical ganglion sympathetic neurons were cultured in compartmentalized Campenot chambers. qRT-PCR and RNA in situ hybridization analyses showed that TH mRNA is present in distal axons. Colocalization experiments with nerve terminal marker proteins suggested that both TH mRNA and protein localize in regions of the axon that resemble nerve terminals (i.e., synaptic boutons). Analysis of polysome-bound RNA showed that TH mRNA is present in polysomes isolated from distal axons. Metabolic labeling of axonally synthesized proteins labeled with the methionine analog, L-azidohomoalanine, showed that TH is locally synthesized in axons. Moreover, the local transfection and translation of exogenous TH mRNA into distal axons facilitated axonal dopamine synthesis. Finally, using chimeric td-Tomato-tagged constructs, we identified a sequence element within the TH 3'UTR that is required for the axonal localization of the reporter mRNA. Taken together, our results provide the first direct evidence that TH mRNA is trafficked to the axon and that the mRNA is locally translated. These findings raise the interesting possibility that the biosynthesis of the catecholamine neurotransmitters is locally regulated in the axon and/or presynaptic nerve terminal.