Treatment of Hepatocellular Carcinoma by Multimodal In Situ Vaccination Using Cryoablation and a Plant Virus Immunostimulant.

PURPOSE: To test the hypothesis that cryoablation combined with intratumoral immunomodulating nanoparticles from cowpea mosaic virus (CPMV) as an in situ vaccination approach induces systemic antitumoral immunity in a murine model of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Mice with bilateral, subcutaneous RIL-175 cell-derived HCCs were randomized to 4 groups: (a) phosphate-buffered saline (control), (b) cryoablation only (Cryo), (c) CPMV-treated only (CPMV), and (d) cryoablation plus CPMV-treated (Cryo + CPMV) (N = 11-14 per group). Intratumoral CPMV was administered every 3 days for 4 doses, with cryoablation performed on the third day. Contralateral tumors were monitored. Tumor growth and systemic chemokine/cytokine levels were measured. A subset of tumors and spleens were harvested for immunohistochemistry (IHC) and flow cytometry. One- or 2-way analysis of variance was performed for statistical comparisons. A P value of <.05 was used as the threshold for statistical significance. RESULTS: At 2 weeks after treatment, the Cryo and CPMV groups, alone or combined, outperformed the control group in the treated tumor; however, the Cryo + CPMV group showed the strongest reduction and lowest variance (1.6-fold ± 0.9 vs 6.3-fold ± 0.5, P < .0001). For the untreated tumor, only Cryo + CPMV significantly reduced tumor growth compared with control (9.2-fold ± 0.9 vs 17.8-fold ± 2.1, P = .01). The Cryo + CPMV group exhibited a transient increase in interleukin-10 and persistently decreased CXCL1. Flow cytometry revealed natural killer cell enrichment in the untreated tumor and increased PD-1 expression in the spleen. Tumor-infiltrating lymphocytes increased in Cryo + CPMV-treated tumors by IHC. CONCLUSIONS: Cryoablation and intratumoral CPMV, alone or combined, demonstrated potent efficacy against treated HCC tumors; however, only cryoablation combined with CPMV slowed the growth of untreated tumors, consistent with an abscopal effect.

Patient Decision Aids Before Informed Consent Conversations for Image-Guided Procedures: Controlled Trials at Two Institutions.

BACKGROUND. Patient decision aids (PDAs) improve informed consent practices. Available PDAs for image-guided procedures are of limited quality. OBJECTIVE. The purpose of this article was to evaluate the impact of PDAs on understanding and satisfaction among patients undergoing informed consent conversations before outpatient image-guided procedures. METHODS. This prospective study included patients awaiting an interventional radiology clinic visit to discuss and obtain informed consent for an image-guided procedure. The study was conducted at two academic medical centers (site A, visits from August 2020 to July 2021; site B, visits from January 2021 to October 2021). Patients were assigned systematically at site A and randomly at site B to electronically receive or not receive a two-page PDA before the visit. PDAs described procedures and their benefits, risks, and alternatives at a sixth- to eighth-grade health literacy level and were vetted by diverse patient focus groups. Patients completed a postvisit survey (site A, by telephone; site B, online) assessing understanding of the procedure and satisfaction with the consent conversation using 5-point scales. Data were pooled between sites. RESULTS. The study included 105 patients (59 men, 46 women; median age, 67 years; 51 from site A, 54 from site B; 53 who received PDA, 52 who did not). Survey response rate was 100% (51/51) at site A and 67% (62/92) at site B. Patients who received, versus did not receive, a PDA reported greater understanding of benefits (4.5 vs 4.0, p < .001), risks (4.4 vs 3.6, p < .001), and alternatives (4.0 vs 3.3, p < .001), and of what procedures involved (4.4 vs 4.1, p = .02) and were more likely to feel that they were provided with enough time with the clinician (4.7 vs 4.5, p = .03), listened to carefully (4.8 vs 4.4, p < .001), free to choose any option including not to have the procedure (4.7 vs 4.3, p < .001), given enough time to make a decision (4.8 vs 4.3, p < .001), encouraged to ask questions (4.8 vs 4.5, p < .001), and had questions answered (4.8 vs 4.4, p = .001). CONCLUSION. Well-vetted plain-language PDAs provided before image-guided procedure consent conversations improve patients' self-perceived understanding of the procedure and satisfaction with the conversation. CLINICAL IMPACT. PDAs can be implemented effectively without requiring additional clinician time or effort.

Virus-Like Particles as Positive Controls for COVID-19 RT-LAMP Diagnostic Assays.

Reverse transcription loop-mediated isothermal amplification (RT-LAMP) is a rapid and inexpensive isothermal alternative to the current gold standard reverse transcription quantitative polymerase chain reaction (RT-qPCR) for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, unlike RT-qPCR, there are no consensus detection regions or optimal RT-LAMP methods, and most protocols do not include internal controls to ensure reliability. Naked RNAs, plasmids, or even RNA from infectious COVID-19 patients have been used as external positive controls for RT-LAMP assays, but such reagents lack the stability required for full-process control. To overcome the lack of proper internal and external positive controls and the instability of the detection RNA, we developed virus-like particles (VLPs) using bacteriophage Qß and plant virus cowpea chlorotic mottle virus (CCMV) for the encapsidation of target RNA, namely a so-called SARS-CoV-2 LAMP detection module (SLDM). The target RNA is a truncated segment of the SARS-CoV-2 nucleocapsid (N) gene and human RNase P gene (internal control) as positive controls for RT-qPCR and RT-LAMP. Target RNAs stably encapsidated in Qß and CCMV VLPs were previously shown to function as full-process controls in RT-qPCR assays, and here we show that SLDMs can fulfill the same function for RT-LAMP and swab-to-test (direct RT-LAMP with heat lysis) assays. The SLDM was validated in a clinical setting, highlighting the promise of VLPs as positive controls for molecular assays.

Stress Conditions Induced by Locoregional Therapies Stimulate Enrichment and Proliferation of Liver Cancer Stem Cells.

PURPOSE: This study tested the hypothesis that stress conditions that simulated percutaneous thermal ablation (PTA), transarterial embolization (TAE), or transarterial chemoembolization stimulated enrichment of hepatocellular carcinoma (HCC) cancer stem cells (hCSCs) and that hCSC inhibitors can suppress this effect. MATERIALS AND METHODS: Human HCC cell lines HepG2 and PLC/PRF/5 were subjected to a 46.5°C heat bath for 10 minutes or to 1% hypoxia for 72 hours without fetal bovine serum and with or without doxorubicin. Cells were then treated with a ß-catenin inhibitor (FH535 or XAV939), a PI3 kinase inhibitor (Ly294002), or niclosamide, a US Food and Drug Administration-approved antihelminthic drug that acts as a mitochondrial decoupler and mixed inhibitor. Surviving cells were analyzed for hCSC markers by flow cytometry, for stemness by colony-forming assay or sphere-forming assay, and for proliferative capacity by MTT assay (where MTT is 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide). Expression of proteins related to CSC renewal and proliferation were analyzed by immunoblotting and immunostaining. RESULTS: Conditions that simulated PTA, TAE, and transarterial chemoembolization resulted in an enrichment of cells bearing hCSC markers (CD133, CD44, and EpCAM). Cells surviving heat stress exhibited higher colony- or sphere-forming capacity and a greater proliferative state. These effects could be suppressed by niclosamide and inhibitors of ß-catenin and PI3 kinase. CONCLUSIONS: Stress conditions induced by locoregional therapies stimulated hCSC enrichment and proliferation, which could be suppressed by niclosamide and inhibitors of pathways important for hCSC renewal. Future studies will determine whether combining locoregional therapies with adjuvant hCSC inhibitors reduces HCC recurrence.

Gender differences among medical students, house staff, and faculty physicians at high risk for suicide: A HEAR report.

BACKGROUND: In comparison with the general population, physicians, and physicians-in-training are at greater risk for suicide. Although key gender differences in suicide risk factors and behaviors have been identified in the general population, the extent to which these differences apply to physicians and physicians-in-training is unclear. Here, we aimed to identify gender differences in risk factors, clinical presentation, and help-seeking behaviors of medical students, house staff, and physician faculty at high risk for suicide. METHODS: We explored gender differences among 450 physicians and trainees meeting criteria for high suicide risk on anonymous online questionnaires completed between 2009 and 2017. RESULTS: High-risk female trainees and physicians had higher mean Patient Health Questionnaire-9 (PHQ-9) scores compared with the males (11.1, standard deviation [SD] 5.1 vs. 9.8, SD 4.7) and were more likely to endorse feeling worried (73.8% vs. 61.2%), irritable (60.4% vs. 49.4%), and stressed (79.6% vs. 70%). High-risk male trainees and physicians were more likely than females to endorse suicidal thoughts (31.2% vs. 22.1%), intense anger (24.3% vs. 16.1%), drinking too much (31.2% vs. 22.3%), and recreational drug or prescription medication use without clinically appropriate follow-up (9.4% vs. 4.3%). There were no gender differences in help-seeking behaviors. CONCLUSIONS: This is the first study to report gender differences among risk factors, presentation, and help-seeking behaviors of physicians, and trainees at high risk for suicide. Our findings are mostly consistent with those of the general population and show that only a minority of at-risk men and women in healthcare sought treatment, highlighting the importance of intervention and suicide prevention in this population.

Quantification of Blood Pressure Changes in the Vascular Compartment When Using an Anti-Reflux Catheter during Chemoembolization versus Radioembolization: A Retrospective Case Series.

PURPOSE: To assess whether blood pressure changes in the downstream vascular compartment are greater with transarterial chemoembolization than transarterial radioembolization (TARE) when using an anti-reflux catheter. MATERIALS AND METHODS: The Surefire Infusion System (Surefire Medical, Inc, Westminster, Colorado) was used for lobar and sublobar administration in 51 drug-eluting embolic transarterial chemoembolization and 55 TARE procedures (22 with resin microspheres [TARE/resin] and 33 with glass microspheres [TARE/glass]). Of patients receiving transarterial chemoembolization and TARE/glass, 97% had hepatocellular carcinomas; 87% of patients receiving TARE/resin had metastases. The absolute (mm Hg) and relative (%) changes in the systemic-hepatic arterial pressure difference (SHAPD) were calculated from simultaneous blood pressure measurements obtained from the femoral artery vascular sheath and the antireflux catheter before, after, and, when feasible, during transarterial chemoembolization or TARE. RESULTS: Transarterial chemoembolization was associated with a significant reduction in SHAPD compared with TARE (13 mm Hg ± 1.7 vs -4.3 mm Hg ± 1.5; P < .001). A reduction in SHAPD led to early termination of 55.6% of lobar and 53.3% of sublobar transarterial chemoembolization procedures compared with only 5.5% of lobar TARE/resin and no TARE/glass procedures. TARE/resin procedures were associated with a significantly greater change in SHAPD compared with TARE/glass procedures (0.9 mm Hg ± 2.7 vs -8.0 mm Hg ± 1.5; P = .0035). CONCLUSIONS: Hepatic arterial pressures in the treated vascular compartment increased more after transarterial chemoembolization than after TARE, suggesting that transarterial chemoembolization resulted in more embolic obstruction of the targeted vascular compartment than TARE.

Radiation Protection for the Fluoroscopy Operator and Staff.

OBJECTIVE: The purposes of this article are to review available data regarding the range of protection devices and garments with a focus on eye protection and to summarize techniques for reducing scatter radiation exposure. CONCLUSION: Fluoroscopy operators and staff can greatly reduce their radiation exposure by wearing properly fitted protective garments, positioning protective devices to block scatter radiation, and adhering to good radiation practices. By understanding the essentials of radiation physics, protective equipment, and the features of each imaging system, operators and staff can capitalize on opportunities for radiation protection while minimizing ergonomic strain. Practicing and promoting a culture of radiation safety can help fluoroscopy operators and staff enjoy long, productive careers helping patients.

Radiation Risk to the Fluoroscopy Operator and Staff.

OBJECTIVE: Recent articles discussing cases of brain cancer in interventionalists have raised concerns regarding the hazards of occupational exposure to ionizing radiation. We review the basics of radiation dose and the potential radiation effects, particularly as they pertain to the operator. Then we present the data regarding the risk of each type of radiation effect to the fluoroscopy operator and staff, with special attention on cancer induction, radiation-induced cataracts, and the pregnant operator. CONCLUSION: Although the evidence overwhelmingly shows that exposure to higher doses of radiation carries a risk of cancer and tissue reactions, the risks of chronic exposure to low-level radiation are less clear. Many studies examining occupational exposure to radiation fail to show an increased risk of stochastic effects of radiation, but the positive results raise concern that the studies are underpowered to consistently detect the small risk. The lack of information in these studies about radiation doses and adherence to radiation protection further confound their interpretation. Large prospective studies of populations with occupational exposure to low-level radiation might clarify this issue. More clearly established are the risks of radiation to the fetus and the risk of cataracts in interventional cardiologists and interventional radiologists. Interventionalists can mitigate these risks by following established radiation safety practices.

Time-Restricted Feeding Attenuates Metabolic Dysfunction-Associated Steatohepatitis and Hepatocellular Carcinoma in Obese Male Mice.

Metabolic dysfunction-associated steatotic liver disease (MASLD) has surpassed the hepatitis B virus and hepatitis C virus as the leading cause of chronic liver disease in most parts of the Western world. MASLD (formerly known as NAFLD) encompasses both simple steatosis and more aggressive metabolic dysfunction-associated steatohepatitis (MASH), which is accompanied by inflammation, fibrosis, and cirrhosis, and ultimately can lead to hepatocellular carcinoma (HCC). There are currently very few approved therapies for MASH. Weight loss strategies such as caloric restriction can ameliorate the harmful metabolic effect of MASH and inhibit HCC; however, it is difficult to implement and maintain in daily life, especially in individuals diagnosed with HCC. In this study, we tested a time-restricted feeding (TRF) nutritional intervention in mouse models of MASH and HCC. We show that TRF abrogated metabolic dysregulation induced by a Western diet without any calorie restriction or weight loss. TRF improved insulin sensitivity and reduced hyperinsulinemia, liver steatosis, inflammation, and fibrosis. Importantly, TRF inhibited liver tumors in two mouse models of obesity-driven HCC. Our data suggest that TRF is likely to be effective in abrogating MASH and HCC and warrant further studies of time-restricted eating in humans with MASH who are at higher risk of developing HCC.

Change Management Strategies Toward Dismantling Race-Based Structural Barriers in Radiology.

Political momentum for antiracist policies grew out of the collective trauma highlighted during the COVID pandemic. This prompted discussions of root cause analyses for differences in health outcomes among historically underserved populations, including racial and ethnic minorities. Dismantling structural racism in medicine is an ambitious goal that requires widespread buy-in and transdisciplinary collaborations across institutions to establish systematic, rigorous approaches that enable sustainable change. Radiology is at the center of medical care and renewed focus on equity, diversity, and inclusion (EDI) provides an opportune window for radiologists to facilitate an open forum to address racialized medicine to catalyze real and lasting change. The framework of change management can help radiology practices create and maintain this change while minimizing disruption. This article discusses how change management principles can be leveraged by radiology to lead EDI interventions that will encourage honest dialogue, serve as a platform to support institutional EDI efforts, and lead to systemic change.

Glycogen synthase kinase 3beta missplicing contributes to leukemia stem cell generation.

Recent evidence suggests that a rare population of self-renewing cancer stem cells (CSC) is responsible for cancer progression and therapeutic resistance. Chronic myeloid leukemia (CML) represents an important paradigm for understanding the genetic and epigenetic events involved in CSC production. CML progresses from a chronic phase (CP) in hematopoietic stem cells (HSC) that harbor the BCR-ABL translocation, to blast crisis (BC), characterized by aberrant activation of beta-catenin within granulocyte-macrophage progenitors (GMP). A major barrier to predicting and inhibiting blast crisis transformation has been the identification of mechanisms driving beta-catenin activation. Here we show that BC CML myeloid progenitors, in particular GMP, serially transplant leukemia in immunocompromised mice and thus are enriched for leukemia stem cells (LSC). Notably, cDNA sequencing of Wnt/beta-catenin pathway regulatory genes, including adenomatous polyposis coli, GSK3beta, axin 1, beta-catenin, lymphoid enhancer factor-1, cyclin D1, and c-myc, revealed a novel in-frame splice deletion of the GSK3beta kinase domain in the GMP of BC samples that was not detectable by sequencing in blasts or normal progenitors. Moreover, BC CML progenitors with misspliced GSK3beta have enhanced beta-catenin expression as well as serial engraftment potential while reintroduction of full-length GSK3beta reduces both in vitro replating and leukemic engraftment. We propose that CP CML is initiated by BCR-ABL expression in an HSC clone but that progression to BC may include missplicing of GSK3beta in GMP LSC, enabling unphosphorylated beta-catenin to participate in LSC self-renewal. Missplicing of GSK3beta represents a unique mechanism for the emergence of BC CML LSC and might provide a novel diagnostic and therapeutic target.

Combining nanomedicine and immune checkpoint therapy for cancer immunotherapy.

Cancer immunotherapy has emerged as a pillar of the cancer therapy armamentarium. Immune checkpoint therapy (ICT) is a mainstay of modern immunotherapy. Although ICT monotherapy has demonstrated remarkable clinical efficacy in some patients, the majority do not respond to treatment. In addition, many patients eventually develop resistance to ICT, disease recurrence, and toxicity from off-target effects. Combination therapy is a keystone strategy to overcome the limitations of monotherapy. With the integration of ICT and any therapy that induces tumor cell lysis and release of tumor-associated antigens (TAAs), ICT is expected to strengthen the coordinated innate and adaptive immune responses to TAA release and promote systemic, cellular antitumor immunity. Nanomedicine is well poised to facilitate combination ICT. Nanoparticles with delivery and/or immunomodulation capacities have been successfully combined with ICT in preclinical applications. Delivery nanoparticles protect and control the targeted release of their cargo. Inherently immunomodulatory nanoparticles can facilitate immunogenic cell death, modification of the tumor microenvironment, immune cell mimicry and modulation, and/or in situ vaccination. Nanoparticles are frequently multifunctional, combining multiple treatment strategies into a single platform with ICT. Nanomedicine and ICT combinations have great potential to yield novel, powerful treatments for patients with cancer. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

The Roots of Structural Racism in the United States and their Manifestations During the COVID-19 Pandemic.

During the COVID-19 pandemic, the disproportionate morbidity and mortality borne by racial minorities, patients of lower socioeconomic status, and patients lacking health insurance reflect pre-existing structural inequities. Structural racism is racial discrimination rooted in history, perpetuated through policies, and manifested in disparities in healthcare, housing, education, employment, and wealth. Although these disparities exert greater impacts on health outcomes than do genetics or behavior, scientists, and policy makers are only beginning to name structural racism as a key determinant of population health and take the necessary steps to dismantle it. In radiology, structural racism impacts how imaging services are utilized. Here we review the history and policies that contribute to structural racism and predispose minority and disadvantaged communities to inferior outcomes during the COVID-19 pandemic in order to identify policy changes that could promote more equitable access to radiologic services.

Reducing Health Disparities in Radiology Through Social Determinants of Health: Lessons From the COVID-19 Pandemic.

During the COVID-19 pandemic, the disproportionate morbidity and mortality borne by racial minorities, patients of lower socioeconomic status, and patients lacking health insurance reflect the critical role of social determinants of health, which are manifestations of entrenched structural inequities. In radiology, social determinants of health lead to disparate use of imaging services through multiple intersecting contributors, on both the provider and patient side, affecting diagnosis and treatment. Disparities on the provider side include ordering of initial or follow-up imaging studies and providing standard-of-care interventional procedures, while patient factors include differences in awareness of screening exams and confidence in the healthcare system. Disparate utilization of mammography and lung cancer screening lead to delayed diagnosis, while differential provision of minimally invasive interventional procedures contributes to differential outcomes related to treatment. Interventions designed to mitigate social determinants of health could help to equalize the healthcare system. Here we review disparities in access and health outcomes in radiology. We investigate underlying contributing factors in order to identify potential policy changes that could promote more equitable health in radiology.

Biomimetic Virus-Like Particles as Severe Acute Respiratory Syndrome Coronavirus 2 Diagnostic Tools.

Coronavirus disease 2019 (COVID-19) is a highly transmissible disease that has affected more than 90% of the countries worldwide. At least 17 million individuals have been infected, and some countries are still battling first or second waves of the pandemic. Nucleic acid tests, especially reverse transcription polymerase chain reaction (RT-PCR), have become the workhorse for early detection of COVID-19 infection. Positive controls for the molecular assays have been developed to validate each test and to provide high accuracy. However, most available positive controls require cold-chain distribution and cannot serve as full-process control. To overcome these shortcomings, we report the production of biomimetic virus-like particles (VLPs) as SARS-CoV-2 positive controls. A SARS-CoV-2 detection module for RT-PCR was encapsidated into VLPs from a bacteriophage and a plant virus. The chimeric VLPs were obtained either by in vivo reconstitution and coexpression of the target detection module and coat proteins or by in vitro assembly of purified detection module RNA sequences and coat proteins. These VLP-based positive controls mimic SARS-CoV-2 packaged ribonucleic acid (RNA) while being noninfectious. Most importantly, we demonstrated that the positive controls are scalable, stable, and can serve broadly as controls, from RNA extraction to PCR in clinical settings.

Time-restricted feeding normalizes hyperinsulinemia to inhibit breast cancer in obese postmenopausal mouse models.

Accumulating evidence indicates that obesity with its associated metabolic dysregulation, including hyperinsulinemia and aberrant circadian rhythms, increases the risk for a variety of cancers including postmenopausal breast cancer. Caloric restriction can ameliorate the harmful metabolic effects of obesity and inhibit cancer progression but is difficult to implement and maintain outside of the clinic. In this study, we aim to test a time-restricted feeding (TRF) approach on mouse models of obesity-driven postmenopausal breast cancer. We show that TRF abrogates the obesity-enhanced mammary tumor growth in two orthotopic models in the absence of calorie restriction or weight loss. TRF also reduces breast cancer metastasis to the lung. Furthermore, TRF delays tumor initiation in a transgenic model of mammary tumorigenesis prior to the onset of obesity. Notably, TRF increases whole-body insulin sensitivity, reduces hyperinsulinemia, restores diurnal gene expression rhythms in the tumor, and attenuates tumor growth and insulin signaling. Importantly, inhibition of insulin secretion with diazoxide mimics TRF whereas artificial elevation of insulin through insulin pumps implantation reverses the effect of TRF, suggesting that TRF acts through modulating hyperinsulinemia. Our data suggest that TRF is likely to be effective in breast cancer prevention and therapy.

Normal human lymph node T follicular helper cells and germinal center B cells accessed via fine needle aspirations.

Germinal centers (GC) are critically important for maturation of the antibody response and generation of memory B cells, processes that form the basis for long-term protection from pathogens. GCs only occur in lymphoid tissue, such as lymph nodes, and are not present in blood. Therefore, GC B cells and GC T follicular helper (TFH) cells are not well-studied in humans under normal healthy conditions, due to the limited availability of healthy lymph node samples. We used a minimally invasive, routine clinical procedure, lymph node fine needle aspirations (LN FNAs), to obtain LN cells from healthy human subjects. This study of 73 LNs demonstrates that human LN FNAs are a safe and feasible technique for immunological research, and suggests benchmarks for human GC biology under noninflammatory conditions. The findings indicate that assessment of the GC response via LN FNAs will have application to the study of human vaccination, allergy, and autoimmune disease.

Liver-directed therapy for hepatocellular carcinoma.

Liver-directed therapy is a critical component of treatment strategies for hepatocellular carcinoma. These therapies included percutaneous image-guided ablation, transarterial chemoembolization, and transarterial radioembolization, and are administered by interventional radiologists. Depending on the stage of disease, a particular treatment modality, or a combination thereof, is expected to be most efficacious in achieving the goals of treatment for a particular patient. This article seeks to review the various liver-directed treatment modalities for treatment of hepatocellular carcinoma, with attention to their efficacy and patient selection criteria.

Caloric restriction does not reverse aging-related changes in hippocampal BDNF.

Caloric restriction (CR) can attenuate the aging-related decline in learning and memory in rats. Understanding the mechanisms underlying this effect could lead to therapies for human memory impairment. We tested the hypotheses that aging is associated with a decline in hippocampal brain-derived neurotrophic factor (BDNF), a growth factor that enhances learning and memory, and that CR increases hippocampal BDNF. We compared BDNF protein levels in hippocampal subregions of young, middle-aged and old rats fed CR or ad libitum (AL) diets. Mean BDNF levels in the dentate gyrus and CA3 did not differ with diet but increased with age. In CA1, BDNF levels were slightly higher in CR than AL rats at middle and old age but did not change across lifespan. These data suggest that mnemonic impairments with age do not reflect a decrease in hippocampal BDNF. Furthermore, if CRs attenuation of aging-related memory changes is mediated by BDNF, then it must be through a small, CA1-specific increase and does not involve reversal of an aging-related decline in BDNF.