Cryopreservation of cerebrospinal fluid cells preserves the transcriptional landscape for single-cell analysis.

Cerebrospinal fluid (CSF) matrix biomarkers have become increasingly valuable surrogate markers of neuropsychiatric diseases in research and clinical practice. In contrast, CSF cells have been rarely investigated due to their relative scarcity and fragility, and lack of common collection and cryopreservation protocols, with limited exceptions for neurooncology and primary immune-based diseases like multiple sclerosis. the advent of a microfluidics-based multi-omics approach to studying individual cells has allowed for the study of cellular phenotyping, intracellular dynamics, and intercellular relationships that provide multidimensionality unable to be obtained through acellular fluid-phase analyses. challenges to cell-based research include site-to-site differences in handling, storage, and thawing methods, which can lead to inaccuracy and inter-assay variability. In the present study, we performed single-cell RNA sequencing (10x Genomics) on fresh or previously cryopreserved human CSF samples from three alternative cryopreservation methods: Fetal Bovine Serum with Dimethyl sulfoxide (FBS/DMSO), FBS/DMSO after a DNase step (a step often included in epigenetic studies), and cryopreservation using commercially available Recovery© media. In comparing relative differences between fresh and cryopreserved samples, we found little effect of the cryopreservation method on being able to resolve donor-linked cell type proportions, markers of cellular stress, and overall gene expression at the single-cell level, whereas donor-specific differences were readily discernable. We further demonstrate the compatibility of fresh and cryopreserved CSF immune cell sequencing using biologically relevant sexually dimorphic gene expression differences by donor. Our findings support the utility and interchangeability of FBS/DMSO and Recovery cryopreservation with fresh sample analysis, providing a methodological grounding that will enable researchers to further expand our understanding of the CSF immune cell contributions to neurological and psychiatric disease.

Effect of Metformin on Plasma and Cerebrospinal Fluid Biomarkers in Non-Diabetic Older Adults with Mild Cognitive Impairment Related to Alzheimer's Disease.

Background: Alzheimer's disease (AD) is a complicated condition involving multiple metabolic and immunologic pathophysiological processes that can occur with the hallmark pathologies of amyloid-ß, tau, and neurodegeneration. Metformin, an anti-diabetes drug, targets several of these disease processes in in vitro and animal studies. However, the effects of metformin on human cerebrospinal fluid (CSF) and plasma proteins as potential biomarkers of treatment remain unexplored. Objective: Using proteomics data from a metformin clinical trial, identify the impact of metformin on plasma and CSF proteins. Methods: We analyzed plasma and CSF proteomics data collected previously (ClinicalTrials.gov identifier: NCT01965756, conducted between 2013 and 2015), and conduced bioinformatics analyses to compare the plasma and CSF protein levels after 8 weeks of metformin or placebo use to their baseline levels in 20 non-diabetic patients with mild cognitive impairment (MCI) and positive AD biomarkers participants. Results: 50 proteins were significantly (unadjusted p < 0.05) altered in plasma and 26 in CSF after 8 weeks of metformin use, with 7 proteins in common (AZU1, CASP-3, CCL11, CCL20, IL32, PRTN3, and REG1A). The correlation between changes in plasma and CSF levels of these 7 proteins after metformin use relative to baseline levels was high (r = 0.98). The proteins also demonstrated temporal stability. Conclusions: Our pilot study is the first to investigate the effect of metformin on plasma and CSF proteins in non-diabetic patients with MCI and positive AD biomarkers and identifies several candidate plasma biomarkers for future clinical trials after confirmatory studies.

Screening, Assessment, and Pharmacologic Treatment of Mild Cognitive Impairment and Early Alzheimer's Disease: The Role for Monoclonal Antibodies.

The Psychiatric Consultation Service at Massachusetts General Hospital sees medical and surgical inpatients with comorbid psychiatric symptoms and conditions. During their twice-weekly rounds, Dr Stern and other members of the Consultation Service discuss diagnosis and management of hospitalized patients with complex medical or surgical problems who also demonstrate psychiatric symptoms or conditions. These discussions have given rise to rounds reports that will prove useful for clinicians practicing at the interface of medicine and psychiatry.Prim Care Companion CNS Disord. 2023;25(6):23f03544. Author affiliations are listed at the end of this article.

Association of BCG Vaccine Treatment With Death and Dementia in Patients With Non-Muscle-Invasive Bladder Cancer.

Importance: The BCG vaccine-used worldwide to prevent tuberculosis-confers multiple nonspecific beneficial effects, and intravesical BCG vaccine is currently the recommended treatment for non-muscle-invasive bladder cancer (NMIBC). Moreover, BCG vaccine has been hypothesized to reduce the risk of Alzheimer disease and related dementias (ADRD), but previous studies have been limited by sample size, study design, or analyses. Objective: To evaluate whether intravesical BCG vaccine exposure is associated with a decreased incidence of ADRD in a cohort of patients with NMIBC while accounting for death as a competing event. Design, Setting, and Participants: This cohort study was performed in patients aged 50 years or older initially diagnosed with NMIBC between May 28, 1987, and May 6, 2021, treated within the Mass General Brigham health care system. The study included a 15-year follow-up of individuals (BCG vaccine treated or controls) whose condition did not clinically progress to muscle-invasive cancer within 8 weeks and did not have an ADRD diagnosis within the first year after the NMIBC diagnosis. Data analysis was conducted from April 18, 2021, to March 28, 2023. Main Outcomes and Measures: The main outcome was time to ADRD onset identified using diagnosis codes and medications. Cause-specific hazard ratios (HRs) were estimated using Cox proportional hazards regression after adjusting for confounders (age, sex, and Charlson Comorbidity Index) using inverse probability scores weighting. Results: In this cohort study including 6467 individuals initially diagnosed with NMIBC between 1987 and 2021, 3388 patients underwent BCG vaccine treatment (mean [SD] age, 69.89 [9.28] years; 2605 [76.9%] men) and 3079 served as controls (mean [SD] age, 70.73 [10.00] years; 2176 [70.7%] men). Treatment with BCG vaccine was associated with a lower rate of ADRD (HR, 0.80; 95% CI, 0.69-0.99), with an even lower rate of ADRD in patients aged 70 years or older at the time of BCG vaccine treatment (HR, 0.74; 95% CI, 0.60-0.91). In competing risks analysis, BCG vaccine was associated with a lower risk of ADRD (5-year risk difference, -0.011; 95% CI, -0.019 to -0.003) and a decreased risk of death in patients without an earlier diagnosis of ADRD (5-year risk difference, -0.056; 95% CI, -0.075 to -0.037). Conclusions and Relevance: In this study, BCG vaccine was associated with a significantly lower rate and risk of ADRD in a cohort of patients with bladder cancer when accounting for death as a competing event. However, the risk differences varied with time.

Non-uniform dystrophin re-expression after CRISPR-mediated exon excision in the dystrophin/utrophin double-knockout mouse model of DMD.

Duchenne muscular dystrophy (DMD) is the most prevalent inherited myopathy affecting children, caused by genetic loss of the gene encoding the dystrophin protein. Here we have investigated the use of the Staphylococcus aureus CRISPR-Cas9 system and a double-cut strategy, delivered using a pair of adeno-associated virus serotype 9 (AAV9) vectors, for dystrophin restoration in the severely affected dystrophin/utrophin double-knockout (dKO) mouse. Single guide RNAs were designed to excise Dmd exon 23, with flanking intronic regions repaired by non-homologous end joining. Exon 23 deletion was confirmed at the DNA level by PCR and Sanger sequencing, and at the RNA level by RT-qPCR. Restoration of dystrophin protein expression was demonstrated by western blot and immunofluorescence staining in mice treated via either intraperitoneal or intravenous routes of delivery. Dystrophin restoration was most effective in the diaphragm, where a maximum of 5.7% of wild-type dystrophin expression was observed. CRISPR treatment was insufficient to extend lifespan in the dKO mouse, and dystrophin was expressed in a within-fiber patchy manner in skeletal muscle tissues. Further analysis revealed a plethora of non-productive DNA repair events, including AAV genome integration at the CRISPR cut sites. This study highlights potential challenges for the successful development of CRISPR therapies in the context of DMD.

Nuclear microRNA-466c regulates Vegfa expression in response to hypoxia.

MicroRNAs are well characterized in their role in silencing gene expression by targeting 3´-UTR of mRNAs in cytoplasm. However, recent studies have shown that miRNAs have a role in the regulation of genes in the nucleus, where they are abundantly located. We show here that in mouse endothelial cell line (C166), nuclear microRNA miR-466c participates in the regulation of vascular endothelial growth factor a (Vegfa) gene expression in hypoxia. Upregulation of Vegfa expression in response to hypoxia was significantly compromised after removal of miR-466c with CRISPR-Cas9 genomic deletion. We identified a promoter-associated long non-coding RNA on mouse Vegfa promoter and show that miR-466c directly binds to this transcript to modulate Vegfa expression. Collectively, these observations suggest that miR-466c regulates Vegfa gene transcription in the nucleus by targeting the promoter, and expands on our understanding of the role of miRNAs well beyond their canonical role.

Cost-effectiveness of Aducanumab and Donanemab for Early Alzheimer Disease in the US.

Importance: Several anti-amyloid monoclonal antibodies have been developed for slowing the progression of Alzheimer disease (AD). Among the furthest developed are aducanumab, which received accelerated approval from the US Food and Drug Administration in 2021, and donanemab, which is currently undergoing phase 3 trials. The cost-effectiveness of these treatments has not been established. Objectives: To estimate the cost-effectiveness of aducanumab and donanemab relative to standard care for early AD in the US. Design, Setting, and Participants: A decision analytic model was used to estimate the lifetime health and economic outcomes of adults with early AD, from US healthcare sector and societal perspectives. Simulated patients had a mean (SD) age of 75.2 (5.5) years; 65% had mild cognitive impairment and 35% had mild dementia. Analyses were conducted from April 6, 2021, to January 20, 2022. Interventions: Standard care, aducanumab (selected inputs including disease progression hazard ratio [HR] of 0.89 [95% CI, 0.63-1.15], annual price of $28 000, and twice-yearly monitoring with magnetic resonance imaging [MRI] of the brain), or donanemab (selected inputs including disease progression HR of 0.68 [95% CI, 0.44-0.99], annual price of $28 000, and twice-yearly monitoring with MRI of the brain and amyloid positron emission tomography [PET] monitoring). Donanemab was switched to placebo after substantial amyloid reduction on PET imaging, which occurred in 27% of patients at 6 months and 55% of patients at 12 months. Main Outcomes and Measures: Quality-adjusted life-years (QALYs); costs, in 2020 US dollars; incremental cost-effectiveness ratios (ICERs); and value-based prices, defined as the maximum price at which a treatment would be cost-effective given a cost-effectiveness threshold of ICER of $150 000/QALY. Results: Lifetime QALYs increased by 0.133 with aducanumab and 0.408 with donanemab. Total health care sector and societal costs increased by $130 100 and $127 800, respectively, with aducanumab and by $78 700 and $71 600, respectively, with donanemab, driven largely by drug costs ($119 000 for aducanumab and $44 600 for donanemab). Health care sector and societal ICERs relative to standard care were $981 000/QALY and $964 000/QALY, respectively, for aducanumab and $193 000/QALY and $176 000/QALY, respectively, for donanemab. In sensitivity analysis, aducanumab's value-based price remained less than $50 000/y, even when assuming a 90% reduction in disease progression. Donanemab's value-based price surpassed $50 000/y once its efficacy exceeded 50%. Conclusions and Relevance: These findings suggest that at current expected prices, neither aducanumab nor donanemab would be cost-effective for early AD in the US. Donanemab's dosing scheme, in which patients suspend treatment on achieving substantial amyloid reductions, may provide a rubric by which sufficiently effective anti-amyloid antibody treatments could be cost-effective even when priced comparably to other biologics.

Broadly active zinc finger protein-guided transcriptional activation of HIV-1.

Human immunodeficiency virus type 1 (HIV-1) causes a persistent viral infection resulting in the demise of immune regulatory cells. Clearance of HIV-1 infection results in integration of proviral DNA into the genome of host cells, which provides a means for evasion and long-term persistence. A therapeutic compound that specifically targets and sustainably activates a latent HIV-1 provirus could be transformative and is the goal for the "shock-and-kill" approach to a functional cure for HIV-1. Substantial progress has been made toward the development of recombinant proteins that target specific genomic loci for gene activation, repression, or inactivation by directed mutations. However, most of these modalities are too large or too complex for efficient therapeutic application. We describe here the development and testing of a novel recombinant zinc finger protein transactivator, ZFP-362-VPR, which specifically and potently enhances proviral HIV-1 transcription both in established latency models and activity across different viral clades. Additionally, ZFP-362-VPR-activated HIV-1 reporter gene expression in a well-established primary human CD4+ T cell latency model and off-target pathways were determined by transcriptome analyses. This study provides clear proof of concept for the application of a novel, therapeutically relevant, protein transactivator to purge cellular reservoirs of HIV-1.

Saving cognitive outcome data in Alzheimer's disease clinical trials during the COVID-19 pandemic: Commentary on the virtual administration of the ADAS-Cog.

Elderly participants in Alzheimer's disease (AD) clinical trials are at high risk of morbidity and mortality with interpersonal exposure to COVID-19, a situation that is likely to continue for the foreseeable future. Yet, in-person neuropsychological assessments remain the mainstay primary outcomes for clinical trials seeking prevention and cure for AD. The Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) is among the most commonly used cognitive assessment in AD clinical trials, and though currently lacking specific guidelines for virtual administrations, it can be used remotely with appropriate modifications and considerations. Here we propose a novel method of virtual administration of the ADAS-Cog, which considers workarounds for technological and human limitations imposed when the participant is no longer sitting across from the test administrator.

An MXD1-derived repressor peptide identifies noncoding mediators of MYC-driven cell proliferation.

MYC controls the transcription of large numbers of long noncoding RNAs (lncRNAs). Since MYC is a ubiquitous oncoprotein, some of these lncRNAs probably play a significant role in cancer. We applied CRISPR interference (CRISPRi) to the identification of MYC-regulated lncRNAs that are required for MYC-driven cell proliferation in the P493-6 and RAMOS human lymphoid cell lines. We identified 320 noncoding loci that play positive roles in cell growth. Transcriptional repression of any one of these lncRNAs reduces the proliferative capacity of the cells. Selected hits were validated by RT-qPCR and in CRISPRi competition assays with individual GFP-expressing sgRNA constructs. We also showed binding of MYC to the promoter of two candidate genes by chromatin immunoprecipitation. In the course of our studies, we discovered that the repressor domain SID (SIN3-interacting domain) derived from the MXD1 protein is highly effective in P493-6 and RAMOS cells in terms of the number of guides depleted in library screening and the extent of the induced transcriptional repression. In the cell lines used, SID is superior to the KRAB repressor domain, which serves routinely as a transcriptional repressor domain in CRISPRi. The SID transcriptional repressor domain is effective as a fusion to the MS2 aptamer binding protein MCP, allowing the construction of a doxycycline-regulatable CRISPRi system that allows controlled repression of targeted genes and will facilitate the functional analysis of growth-promoting lncRNAs.

Neutralization Breadth and Potency of Single-Chain Variable Fragments Derived from Broadly Neutralizing Antibodies Targeting Multiple Epitopes on the HIV-1 Envelope.

Passive administration of HIV-directed broadly neutralizing antibodies (bNAbs) can prevent infection in animal models, and human efficacy trials are under way. Single-chain variable fragments (scFv), comprised of only the variable regions of antibody heavy and light chains, are smaller molecules that may offer advantages over full-length IgG. We designed and expressed scFv of HIV bNAbs prioritized for clinical testing that target the V2-apex (CAP256-VRC26.25), V3-glycan supersite (PGT121), CD4 binding site (3BNC117), and MPER (10E8v4). The use of either a 15- or 18-amino-acid glycine-serine linker between the heavy- and light-chain fragments provided adequate levels of scFv expression. When tested against a 45-multisubtype virus panel, all four scFv retained good neutralizing activity, although there was variable loss of function compared to the parental IgG antibodies. For CAP256-VRC26.25, there was a significant 138-fold loss of potency that was in part related to differential interaction with charged amino acids at positions 169 and 170 in the V2 epitope. Potency was reduced for the 3BNC117 (13-fold) and PGT121 (4-fold) scFv among viruses lacking the N276 and N332 glycans, respectively, and in viruses with a longer V1 loop for PGT121. This suggested that scFv interacted with their epitopes in subtly different ways, with variation at key residues affecting scFv neutralization more than the matched IgGs. Remarkably, the scFv of 10E8v4 maintained breadth of 100% with only a minor reduction in potency. Overall, scFv of clinically relevant bNAbs had significant neutralizing activity, indicating that they are suitable for passive immunization to prevent HIV-1 infection.IMPORTANCE Monoclonal antibodies have been isolated against conserved epitopes on the HIV trimer and are being investigated for passive immunization. Some of the challenges associated with full-sized antibody proteins may be overcome by using single-chain variable fragments (scFv). These smaller forms of antibodies can be produced more efficiently, may show fewer off-target effects with increased tissue penetration, and are more adaptable to vectored-mediated expression than IgG. Here, we demonstrate that scFv of four HIV-directed bNAbs (CAP256-VRC26.25, PGT121, 3BNC117, and 10E8v4) had significant neutralizing activity against diverse global strains of HIV. Loss of potency and/or breadth was shown to be due to increased dependence of the scFv on key residues within the epitope. These smaller antibody molecules with functional activity in the therapeutic range may be suitable for further development as passive immunity for HIV prevention.

AAV-Mediated Expression of Broadly Neutralizing and Vaccine-like Antibodies Targeting the HIV-1 Envelope V2 Region.

HIV-1 infection continues to be a global health challenge and a vaccine is urgently needed. Broadly neutralizing antibodies (bNAbs) are considered essential as they inhibit multiple HIV-1 strains, but they are difficult to elicit by conventional immunization. In contrast, non-neutralizing antibodies that correlated with reduced risk of infection in the RV144 HIV vaccine trial are relatively easy to induce, but responses are not durable. To overcome these obstacles, adeno-associated virus (AAV) vectors were used to provide long-term expression of antibodies targeting the V2 region of the HIV-1 envelope protein, including the potent CAP256-VRC26.25 bNAb, as well as non-neutralizing CAP228 antibodies that resemble those elicited by vaccination. AAVs mediated effective antibody expression in cell culture and immunocompetent mice. Mean concentrations of human immunoglobulin G (IgG) in mouse sera increased rapidly following a single AAV injection, reaching 8-60 µg/mL for CAP256 antibodies and 44-220 µg/mL for CAP228 antibodies over 24 weeks, but antibody concentrations varied for individual mice. Secreted antibodies collected from serum retained the expected binding and neutralizing activity. The vectors generated here are, therefore, suitable for the delivery of V2-targeting HIV antibodies, and they could be used in a vectored immunoprophylaxis (VIP) approach to sustain the level of antibody expression required to prevent HIV infection.

Effect of transcription inhibition and generation of suppressive viral non-coding RNAs.

BACKGROUND: HIV-1 patients receiving combination antiretroviral therapy (cART) survive infection but require life-long adherence at high expense. In chronic cART-treated patients with undetectable viral titers, cell-associated viral RNA is still detectable, pointing to low-level viral transcriptional leakiness. To date, there are no FDA-approved drugs against HIV-1 transcription. We have previously shown that F07#13, a third generation Tat peptide mimetic with competitive activity against Cdk9/T1-Tat binding sites, inhibits HIV-1 transcription in vitro and in vivo. RESULTS: Here, we demonstrate that increasing concentrations of F07#13 (0.01, 0.1, 1 µM) cause a decrease in Tat levels in a dose-dependent manner by inhibiting the Cdk9/T1-Tat complex formation and subsequent ubiquitin-mediated Tat sequestration and degradation. Our data indicate that complexes I and IV contain distinct patterns of ubiquitinated Tat and that transcriptional inhibition induced by F07#13 causes an overall reduction in Tat levels. This reduction may be triggered by F07#13 but ultimately is mediated by TAR-gag viral RNAs that bind suppressive transcription factors (similar to 7SK, NRON, HOTAIR, and Xist lncRNAs) to enhance transcriptional gene silencing and latency. These RNAs complex with PRC2, Sin3A, and Cul4B, resulting in epigenetic modifications. Finally, we observed an F07#13-mediated decrease of viral burden by targeting the R region of the long terminal repeat (HIV-1 promoter region, LTR), promoting both paused polymerases and increased efficiency of CRISPR/Cas9 editing in infected cells. This implies that gene editing may be best performed under a repressed transcriptional state. CONCLUSIONS: Collectively, our results indicate that F07#13, which can terminate RNA Polymerase II at distinct sites, can generate scaffold RNAs, which may assemble into specific sets of "RNA Machines" that contribute to gene regulation. It remains to be seen whether these effects can also be seen in various clades that have varying promoter strength, mutant LTRs, and in patient samples.

Acute Pharmacological Management of Behavioral and Emotional Dysregulation Following a Traumatic Brain Injury: A Systematic Review of the Literature.

BACKGROUND: Traumatic brain injury (TBI) is an increasingly common cause of behavioral and emotional dysregulation among hospitalized patients. While consultation-liaison psychiatrists are often called to help manage these behaviors, acute pharmacological management guidelines are limited. OBJECTIVE: Conduct a systematic review to determine which pharmacological measures are supported by the literature for targeting agitation and aggression in the acute time period following a TBI. METHODS: In a systematic review of MEDLINE, Embase, PsycInfo, ClinicalTrials.gov and the Cochrane Library, we identified and then analyzed publications that investigated the pharmacological management of behavioral and emotional dysregulation following a TBI during the acute time period following injury. RESULTS: There were a limited number of high quality studies that met our inclusion criteria, including only five randomized controlled trials. The majority of the literature identified consisted of case reports or case series. Trends identified in the literature reviewed suggested that amantadine, propranolol, and anti-epileptics were the best supported medications to consider. For many medication classes, the time of medication initiation and duration of treatment, relative to the time of injury, may impact the effect observed. CONCLUSIONS: The pharmacological management of agitated patients immediately following a TBI is still an area of much-needed research, as there is limited data-driven guidance in the literature.

Stable Transcriptional Repression and Parasitism of HIV-1.

Gene-based therapies represent a promising treatment for HIV-1 infection, as they offer the potential for sustained viral inhibition and reduced treatment interventions. One approach developed here involves using conditionally replicating vectors (CR-vectors). CR-vectors utilize HIV-expressed proteins to replicate and disseminate along with HIV into the budding viral particles, thereby co-infecting target cellular reservoirs. We generated and characterized several CR-vectors carrying various therapeutic payloads of non-coding RNAs targeted to HIV-1, both transcriptionally and post-transcriptionally. Both virus and vector expression was followed in cell culture systems and T cells in the presence and absence of mycophenolic acid (MPA) selection. We find here that CR-vectors functionally suppress HIV expression in a long-term stable manner and that transcriptional targeting of and epigenetic silencing of HIV can be passaged to newly infected cells by the action of the CR-vector, ultimately establishing a sustained parasitism of HIV. Our findings suggest that CR-vectors with modulatory non-coding RNAs may be a viable approach to achieving long-term sustained suppression of HIV-1, leading ultimately to a functional cure.

Receptor-targeted aptamer-siRNA conjugate-directed transcriptional regulation of HIV-1.

Gene-based therapies represent a promising therapeutic paradigm for the treatment of HIV-1, as they have the potential to maintain sustained viral inhibition with reduced treatment interventions. Such an option may represent a long-term treatment alternative to highly active antiretroviral therapy. Methods: We previously described a therapeutic approach, referred to as transcriptional gene silencing (TGS), whereby small noncoding RNAs directly inhibit the transcriptional activity of HIV-1 by targeting sites within the viral promoter, specifically the 5' long terminal repeat (LTR). TGS differs from traditional RNA interference (RNAi) in that it is characterized by concomitant silent-state epigenetic marks on histones and DNA. To deliver TGS-inducing RNAs, we developed functional RNA conjugates based on the previously reported dual function of the gp120 (A-1) aptamer conjugated to 27-mer Dicer-substrate anti-HIV-1 siRNA (dsiRNA), LTR-362. Results: We demonstrate here that high levels of processed guide RNAs localize to the nucleus in infected T lymphoblastoid CEM cell line and primary human CD4+ T-cells. Treatment of the aptamer-siRNA conjugates induced TGS with an ~10-fold suppression of viral p24 levels as measured at day 12 post infection. To explore the silencing efficacy of aptamer-siRNA conjugates in vivo, HIV-1-infected humanized NOD/SCID/IL2 rγnull mice (hu-NSG) were treated with the aptamer-siRNA conjugates. Systemic delivery of the A-1-stick-LTR-362 27-mer siRNA conjugates suppressed HIV-1 infection and protected CD4+ T cell levels in viremia hu-NSG mice. Principle conclusions: Collectively these data suggest that the gp120 aptamer-dsiRNA conjugate design is suitable for systemic delivery of small RNAs that can be used to suppress HIV-1.

The impact of skeletal muscle on the pharmacokinetics and toxicity of 5-fluorouracil in colorectal cancer.

PURPOSE: Great heterogeneity exists in the ability of adults with cancer to tolerate chemotherapy. Variability in body composition may affect rates of metabolism of cytotoxic agents and contribute to the variable chemotherapy toxicity observed. The objective of this exploratory study was to examine the association of low skeletal muscle, commonly known as sarcopenia, on the pharmacokinetics (PKs) of 5-fluorouracil (5FU) in patients receiving FOLFOX for colorectal cancer. METHODS: We performed a secondary analysis of a completed multicenter trial that investigated PK-guided 5FU dosing in patients receiving mFOLFOX6 +/- bevacizumab for colorectal cancer. Cycle 1 PK samples were obtained 2-44 h after the start of the 5FU infusion (steady state). RESULTS: No significant differences in first cycle 5FU area-under-the-concentration-time-curve (AUC) were found between sarcopenic and non-sarcopenic patients (17.3 vs. 19.3 AUC, p = 0.43). Patients with grade 3/4 toxicity had a higher dose of 5FU per kg lean body mass (LBM) (105 vs. 93 mg/kg, p = 0.06), most notably for hematological toxicities (110 vs. 94 mg/kg, p = 0.002); however, no correlation between the dose/LBM and 5FU AUC was found. CONCLUSIONS: Although our results did not confirm the impact of low skeletal muscle on PKs of 5FU, further research exploring the impact of body composition on chemotherapy PKs and related toxicities is warranted with the potential for alternative dosing strategies in sarcopenic patients to reduce unnecessary toxicities while maintaining efficacy.