Mitigating inequity: ethically prioritizing patients for CAR T-cell therapy.

Manufacturing capacity and institutional infrastructure to deliver chimeric antigen receptor T-cell therapies (CAR-T) are pressured to keep pace with the growing number of approved products and expanding eligible patient population for this potentially life-saving therapy. Consequently, many cell therapy programs must make difficult decisions about which patient should get the next available treatment slot. This situation requires an ethical framework to ensure fair and equitable decision-making. In this perspective, we discuss the application of Accountability for Reasonableness (A4R), a priority-setting framework grounded in procedural justice, to the problem of limited CAR-T slots at our institution. We formed a multidisciplinary working group spanning several hematological malignancies. Through multiple rounds of partner engagement, we used A4R guiding principles to identify 4 main criteria to prioritize patients for CAR-T: medical benefit, safety/risk of complications, psychosocial factors, and medical urgency. Associated measures/tools and an implementation process were developed. We discuss further how ethical principles of fairness and equity demand a consistent approach within health systems that does not disadvantage medically underserved or underrepresented populations and supports overcoming barriers to care. In our commitment to transparency and collaboration, we make our tools available to others, ideally to be used to engage in their own A4R process, adapting the tools to their unique environments. Our hope is that our preliminary work will support the advancement of further study in this area globally, aiming for justice in resource allocation for all potential CAR-T candidates, wherever they may seek care.

Decision-making and autonomy among participants in early-phase cancer immunotherapy trials: a qualitative study.

BACKGROUND: Participants considering early-phase cancer clinical trials (CTs) need to understand the unique risks and benefits prior to providing informed consent. This qualitative study explored the factors that influence patients' decisions about participating in early-phase cancer immunotherapy CTs through the ethical lens of relational autonomy. METHODS: Using an interpretive descriptive design, interviews were conducted with 21 adult patients with advanced cancer who had enrolled in an early-phase CT. Data was analyzed using relational autonomy ethical theory and constant comparative analysis. RESULTS: The extent to which participants perceived themselves as having a choice to participate in early-phase cancer immunotherapy CTs was a central construct. Perceptions of choice varied according to whether participants characterized their experience as an act of desperation or as an opportunity to receive a novel treatment. Intersecting psychosocial and structural factors influenced participants' decision making about participating in early-phase cancer immunotherapy trials. These relational factors included: (1) being provided with hope; (2) having trust; (3) having the ability to withdraw; and (4) timing constraints. CONCLUSIONS: Findings highlight the continuum of perceived choice that exists among patients with cancer when considering participation in early-phase cancer immunotherapy CTs. All participants were interpreted as exhibiting some degree of relational autonomy within the psychosocial and structural context of early-phase CT decision making. This study offers insights into the intersection of cancer care delivery, personal beliefs and values, and established CT processes and structures that can inform future practices and policies associated with early-phase cancer immunotherapy CTs to better support patients in making informed decisions.

Biodistribution of lentiviral transduced adipose-derived stem cells for "ex-vivo" regional gene therapy for bone repair.

Ex-vivo gene therapy has been shown to be an effective method for treating bone defects in pre-clinical models. As gene therapy is explored as a potential treatment option in humans, an assessment of the safety profile becomes an important next step. The purpose of this study was to evaluate the biodistribution of viral particles at the defect site and various internal organs in a rat femoral defect model after implantation of human ASCs transduced with lentivirus (LV) with two-step transcriptional activation (TSTA) of bone morphogenetic protein-2 (LV-TSTA-BMP-2). Animals were sacrificed at 4-, 14-, 56-, and 84-days post implantation. The defects were treated with either a standard dose (SD) of 5 million cells or a high dose (HD) of 15 million cells to simulate a supratherapeutic dose. Treatment groups included (1) SD LV-TSTA-BMP-2 (2) HD LV-TSTA-BMP-2, (3) SD LV-TSTA-GFP (4) HD LV-TSTA-GFP and (5) SD nontransduced cells. The viral load at the defect site and ten organs was assessed at each timepoint. Histology of all organs, ipsilateral tibia, and femur were evaluated at each timepoint. There were nearly undetectable levels of LV-TSTA-BMP-2 transduced cells at the defect site at 84-days and no pathologic changes in any organ at all timepoints. In conclusion, human ASCs transduced with a lentiviral vector were both safe and effective in treating critical size bone defects in a pre-clinical model. These results suggest that regional gene therapy using lentiviral vector to treat bone defects has the potential to be a safe and effective treatment in humans.

Influence of donor age and comorbidities on transduced human adipose-derived stem cell in vitro osteogenic potential.

Human adipose-derived mesenchymal stem cells (ASCs) transduced with a lentiviral vector system to express bone morphogenetic protein 2 (LV-BMP-2) have been shown to reliably heal bone defects in animal models. However, the influence of donor characteristics such as age, sex, race, and medical co-morbidities on ASC yield, growth and bone regenerative capacity, while critical to the successful clinical translation of stem cell-based therapies, are not well understood. Human ASCs isolated from the infrapatellar fat pads in 122 ASC donors were evaluated for cell growth characteristics; 44 underwent additional analyses to evaluate in vitro osteogenic potential, with and without LV-BMP-2 transduction. We found that while female donors demonstrated significantly higher cell yield and ASC growth rates, age, race, and the presence of co-morbid conditions were not associated with differences in proliferation. Donor demographics or the presence of comorbidities were not associated with differences in in vitro osteogenic potential or stem cell differentiation, except that transduced ASCs from healthy donors produced more BMP-2 at day 2. Overall, donor age, sex, race, and the presence of co-morbid conditions had a limited influence on cell yield, proliferation, self-renewal capacity, and osteogenic potential for non-transduced and transduced (LV-BMP-2) ASCs. These results suggest that ASCs are a promising resource for both autologous and allogeneic cell-based gene therapy applications.

Neuro-oncology clinicians' perspectives on factors affecting brain cancer patients' access to medical assistance in dying: A qualitative study.

In most jurisdictions where medical assistance in dying (MAiD) is legal, patients must have decision-making capacity. Brain cancer often damages the cognitive networks required to maintain decision-making capacity. Using qualitative methodology guided by a relational ethics conceptual framework, this study explored neuro-oncology clinicians' perspectives on access to and eligibility for MAiD for patients diagnosed with brain cancer. We interviewed 24 neuro-oncology clinicians from 6 countries. Participants described the unique challenges facing brain cancer patients, potentially resulting in their inequitable access to MAiD. The findings highlight the importance of early end-of-life conversations, advance care planning, and access to end-of-life treatment options.

A Race to the End: Family Caregivers' Experience of Medical Assistance in Dying (MAiD)-a Qualitative Study.

BACKGROUND: The June 2016 legalization of medical assistance in dying (MAiD) provided an added layer of choice to end-of-life care in Canada. Family caregivers play an important role in patient end-of-life decision-making. They may experience unique psychological burden or distress associated with their role. However, we know little about the caregiver experience associated with patient MAiD requests and the nature of psychosocial supports caregivers require before, during, and following MAiD intervention. OBJECTIVE: The objective of this study is to better understand the caregiver experience of MAiD within the Canadian legal landscape following Bill C-14. DESIGN: Caregiver experience was examined based on qualitative, semi-structured interviews. PARTICIPANTS: A total of 22 caregivers of patients who had requested MAiD were interviewed. APPROACH: Transcripts were recorded, transcribed, and analyzed based on grounded theory methodology. KEY RESULTS: The caregiver experience of MAiD within the legal framework was found to be understood as a "race to the end," with the ultimate goal of creating an ideal dying experience for the patient while balancing a threat to capacity that would undermine their access to MAiD. Caregivers can be described within the overarching framework as either co-runners or onlookers. Sources of caregiver distress were linked to these roles. CONCLUSIONS: The "race to the end" theoretical model contributes new knowledge and understanding that can inform the development of tailored support services for caregivers, the impact of legislative changes on this population, and future research examining decision-making near end of life and the caregiver experience.

Clinical ethics consultations: a scoping review of reported outcomes.

BACKGROUND: Clinical ethics consultations (CEC) can be complex interventions, involving multiple methods, stakeholders, and competing ethical values. Despite longstanding calls for rigorous evaluation in the field, progress has been limited. The Medical Research Council (MRC) proposed guidelines for evaluating the effectiveness of complex interventions. The evaluation of CEC may benefit from application of the MRC framework to advance the transparency and methodological rigor of this field. A first step is to understand the outcomes measured in evaluations of CEC in healthcare settings. OBJECTIVE: The primary objective of this review was to identify and map the outcomes reported in primary studies of CEC. The secondary objective was to provide a comprehensive overview of CEC structures, processes, and roles to enhance understanding and to inform standardization. METHODS: We searched electronic databases to identify primary studies of CEC involving patients, substitute decision-makers and/or family members, clinicians, healthcare staff and leaders. Outcomes were mapped across five conceptual domains as identified a priori based on our clinical ethics experience and preliminary literature searches and revised based on our emerging interpretation of the data. These domains included personal factors, process factors, clinical factors, quality, and resource factors. RESULTS: Forty-eight studies were included in the review. Studies were highly heterogeneous and varied considerably regarding format and process of ethical intervention, credentials of interventionist, population of study, outcomes reported, and measures employed. In addition, few studies used validated measurement tools. The top three outcome domains that studies reported on were quality (n = 31), process factors (n = 23), and clinical factors (n = 19). The majority of studies examined multiple outcome domains. All five outcome domains were multidimensional and included a variety of subthemes. CONCLUSIONS: This scoping review represents the initial phase of mapping the outcomes reported in primary studies of CEC and identifying gaps in the evidence. The confirmed lack of standardization represents a hindrance to the provision of high quality intervention and CEC scientific progress. Insights gained can inform the development of a core outcome set to standardize outcome measures in CEC evaluation research and enable scientifically rigorous efficacy trials of CEC.

Nonarthroplasty Management of Shoulder Arthritis in the Aging Athlete: Biologics and Arthroscopy.

Glenohumeral arthritis in athletes or young and active individuals constitutes a challenging clinical problem, and multiple factors should be taken into consideration when deciding on nonsurgical or surgical treatment in this patient cohort. Selection of therapy should be based on clinical evidence, but the therapeutic strategy should align with patient expectations. Patient education on the nature and progression of shoulder osteoarthritis may facilitate the decision-making process regarding the selection of treatment. The orthopaedic surgeon should be knowledgeable about the nonarthroplasty options for the management of shoulder osteoarthritis in the aging athlete, with special focus on nonsurgical treatment options and shoulder arthroscopy.

Shoulder Arthroplasty in the Aging Athlete: Considerations in the Younger Patient.

Shoulder arthroplasty has become an increasingly common option for the management of glenohumeral osteoarthritis in younger, higher demand, and athletic individuals. Patients with shoulder arthritis in whom nonsurgical measures fail and who are not candidates for arthroscopic treatment may be evaluated for shoulder arthroplasty. Available options include shoulder hemiarthroplasty, with or without biologic glenoid resurfacing, total shoulder arthroplasty, and less commonly reverse total shoulder arthroplasty. The orthopaedic surgeon should be aware of the evolution and current use of the different shoulder replacement techniques in young active patients with glenohumeral osteoarthritis. In addition, it is important to review practical guidelines and issues with the implementation of those techniques when treating patients with shoulder arthritis who want to return to sport activity postoperatively.

Neuro-Oncology Clinicians' Attitudes and Perspectives on Medical Assistance in Dying.

BACKGROUND: Medical assistance in dying (MAiD), also known as physician-assisted death, is currently legal in several locations across the globe. Brain cancer or its treatments can lead to cognitive impairment, which can impact decision-making capacity for MAiD. OBJECTIVE: We sought to explore neuro-oncology clinicians' attitudes and perspectives on MAiD, including interpretation of decision-making capacity for patient MAiD eligibility. METHODS: An online survey was distributed to members of national and international neuro-oncology societies. We asked questions about decision-making capacity and MAiD, in part using hypothetical patient scenarios. Multiple choice and free-text responses were captured. RESULTS: There were 125 survey respondents. Impaired cognition was identified as the most important factor that would signal a decline in patient capacity. At least 26% of survey respondents had moral objections to MAiD. Respondents thought that different hypothetical patients had capacity to make a decision about MAiD (range 18%-58%). In other hypothetical scenarios, fewer clinicians were willing to support a MAiD decision for a patient with an oligodendroglioma (26%) vs. glioblastoma (41%-70%, depending on the scenario). Time since diagnosis, performance status, and patient age seemed to affect support for MAiD decisions (Fisher's exact P-values 0.007, < 0.001, and 0.049, respectively). CONCLUSION: While there are differing opinions on the moral permissibility of MAiD in general and for neuro-oncology patients, most clinicians agree that capacity must be assessed carefully before a decision is made. End-of-life discussions should happen early, before the capacity is lost. Our results can inform assessments of patient capacity in jurisdictions where MAiD is legal.

Medical Assistance in Dying in patients with advanced cancer and their caregivers: a mixed methods longitudinal study protocol.

BACKGROUND: The legal criteria for medical assistance in dying (MAiD) for adults with a grievous and irremediable medical condition were established in Canada in 2016. There has been concern that potentially reversible states of depression or demoralization may contribute to the desire for death (DD) and requests for MAiD. However, little is known about the emergence of the DD in patients, its impact on caregivers, and to what extent supportive care interventions affect the DD and requests for MAiD. The present observational study is designed to determine the prevalence, predictors, and experience of the DD, requests for MAiD and MAiD completion in patients with advanced or metastatic cancer and the impact of these outcomes on their primary caregivers. METHODS: A cohort of patients with advanced or metastatic solid tumour cancers and their primary caregivers will be recruited from a large tertiary cancer centre in Toronto, Ontario, Canada, to a longitudinal, mixed methods study. Participants will be assessed at baseline for diagnostic information, sociodemographic characteristics, medical history, quality of life, physical and psychological distress, attitudes about the DD and MAiD, communication with physicians, advance care planning, and use of psychosocial and palliative care interventions. Measures will subsequently be completed every six months and at the time of MAiD requests. Quantitative assessments will be supplemented by qualitative interviews in a subset of participants, selected using quota sampling methods. DISCUSSION: This study has the potential to add importantly to our understanding of the prevalence and determinants of the DD, MAiD requests and completions in patients with advanced or metastatic cancer and of the experience of both patients and caregivers in this circumstance. The findings from this study may also assist healthcare providers in their conversations about MAiD and the DD with patients and caregivers, inform healthcare providers to ensure appropriate access to MAiD, and guide modifications being considered to broaden MAiD legislation and policy.

Perceptions of and decision making about clinical trials in adolescent and young adults with Cancer: a qualitative analysis.

BACKGROUND: Adolescent and young adults (AYA) enrolment rates into cancer clinical trials (CCT) are the lowest of any age group globally. As AYA have distinct biological, psychosocial and relational needs, we aimed to explore any unique factors influencing their CCT decision-making process, including AYA-specific perceptions or attitudes towards CCT. METHODS: Qualitative interpretive descriptive methodology was used to explore AYA perceptions and decision-making related to CCT. An analytic approach conducive to inductive imagining and exploratory questioning was used in order to generate insights and interpret data. RESULTS: A total of 21 AYA were interviewed (median age: 31 (18-39)). Twelve (57%) participants had previously been approached to participate in CCT. Major themes influencing trial enrolment decisions were: 1) severity of illness/urgency for new treatment 2) side effect profile of investigational drug in the short and long term (e.g., impact on future quality of life) 3) who approached patient for trial participation (oncologist vs. other) 4) additional information found on-line about the trial and investigators, and 5) family, friends and peer group opinion regarding the CCT. CONCLUSIONS: Several psychosocial and relational factors were identified as influencing AYA CCT decisions, some of which are unique to this demographic. Specific strategies to address barriers to CCT and enable supportive decision-making include: 1) involving family in decision-making and 2) helping AYA appreciate short- and long-term implications of trial participation. Finally, exploring social networking and general education about CCT that AYA can independently access may increase participation.

Cancer patient decision making related to clinical trial participation: an integrative review with implications for patients' relational autonomy.

PURPOSE: Oncology clinical trials are necessary for the improvement of patient care as they have the ability to confirm the efficacy and safety of novel cancer treatments and in so doing, contribute to a solid evidence base on which practitioners and patients can make informed treatment decisions. However, only 3-5 % of adult cancer patients enroll in clinical trials. Lack of participation compromises the success of clinical trials and squanders an opportunity for improving patient outcomes. This literature review summarizes the factors and contexts that influence cancer patient decision making related to clinical trial participation. METHODS: An integrative review was undertaken within PubMed, CINAHL, and EMBASE databases for articles written between 1995 and 2012 and archived under relevant keywords. Articles selected were data-based, written in English, and limited to adult cancer patients. RESULTS: In the 51 articles reviewed, three main types of factors were identified that influence cancer patients' decision making about participation in clinical trials: personal, social, and system factors. Subthemes included patients' trust in their physician and the research process, undue influence within the patient-physician relationship, and systemic social inequalities. How these factors interact and influence patients' decision-making process and relational autonomy, however, is insufficiently understood. CONCLUSIONS: Future research is needed to further elucidate the sociopolitical barriers and facilitators of clinical trial participation and to enhance ethical practice within clinical trial enrolment. This research will inform targeted education and support interventions to foster patients' relational autonomy in the decision-making process and potentially improve clinical trial participation rates.

A risk screening tool for ethical appraisal of evidence-generating initiatives.

BACKGROUND: The boundaries between health-related research and practice have become blurred as initiatives traditionally considered to be practice (e.g., quality improvement, program evaluation) increasingly use the same methodology as research. Further, the application of different ethical requirements based on this distinction raises concerns because many initiatives commonly labelled as "non-research" are associated with risks to patients, participants, and other stakeholders, yet may not be subject to any ethical oversight. Accordingly, we sought to develop a tool to facilitate the systematic identification of risks to human participants and determination of risk level across a broad range of projects (e.g., clinical research, laboratory-based projects, population-based surveillance, and program evaluation) and health-related contexts. This paper describes the development of the Public Health Ontario (PHO) Risk Screening Tool. METHOD: Development of the PHO Risk Screening Tool included: (1) preparation of a draft risk tool (n = 47 items); (2) expert appraisal; (3) internal stakeholder validation; (4) external validation; (5) pilot testing and evalution of the draft tool; and (6) revision after 1 year of testing. RESULTS: A risk screening tool was generated consisting of 20 items organized into five risk domains: Sensitivity; Participant Selection, Recruitment and Consent; Data/Sample Collection; Identifiability and Privacy Risk; and Commercial Interests. The PHO Risk Screening Tool is an electronic tool, designed to identify potential project-associated risks to participants and communities and to determine what level of ethics review is required, if any. The tool features an easy to use checklist format that generates a risk score (0-3) associated with a suggested level of ethics review once all items have been completed. The final score is based on a threshold approach to ensure that the final score represents the highest level of risk identified in any of the domains of the tool. CONCLUSIONS: The PHO Risk Screening Tool offers a practical solution to the problem of how to maintain accountability and appropriate risk oversight that transcends the boundaries of research and practice. We hope that the PHO Risk Screening Tool will prove useful in minimizing the problems of over and under protection across a wide range of disciplines and jurisdictions.

In vivo effects of cell seeding technique in an ex vivo regional gene therapy model for bone regeneration.

When delivering cells on a scaffold to treat a bone defect, the cell seeding technique determines the number and distribution of cells within a scaffold, however the optimal technique has not been established. This study investigated if human adipose-derived stem cells (ASCs) transduced with a lentiviral vector to overexpress bone morphogenetic protein 2 (BMP-2) and loaded on a scaffold using dynamic orbital shaker could reduce the total cell dose required to heal a critical sized bone defect when compared with static seeding. Human ASCs were loaded onto a collagen/biphasic ceramic scaffold using static loading and dynamic orbital shaker techniques, compared with our labs standard loading technique, and implanted into femoral defects of nude rats. Both a low dose and standard dose of transduced cells were evaluated. Outcomes investigated included BMP-2 production, radiographic healing, micro-computerized tomography, histologic assessment, and biomechanical torsional testing. BMP-2 production was higher in the orbital shaker cohort compared with the static seeding cohort. No statistically significant differences were noted in radiographic, histomorphometric, and biomechanical outcomes between the low-dose static and dynamic seeding groups, however the standard-dose static seeding cohort had superior biomechanical properties. The standard-dose 5 million cell dose standard loading cohort had superior maximum torque and torsional stiffness on biomechanical testing. The use of orbital shaker technique was labor intensive and did not provide equivalent biomechanical results with the use of fewer cells.

Access to cancer clinical trials for racialised older adults: an equity-focused rapid scoping review protocol.

BACKGROUND: The intersection of race and older age compounds existing health disparities experienced by historically marginalised communities. Therefore, racialised older adults with cancer are more disadvantaged in their access to cancer clinical trials compared with age-matched counterparts. To determine what has already been published in this area, the rapid scoping review question are: what are the barriers, facilitators and potential solutions for enhancing access to cancer clinical trials among racialised older adults? METHODS: We will use a rapid scoping review methodology in which we follow the six-step framework of Arksey and O'Malley, including a systematic search of the literature with abstract and full-text screening to be conducted by two independent reviewers, data abstraction by one reviewer and verification by a second reviewer using an Excel data abstraction sheet. Articles focusing on persons aged 18 and over who identify as a racialised person with cancer, that describe therapies/therapeutic interventions/prevention/outcomes related to barriers, facilitators and solutions to enhancing access to and equity in cancer clinical trials will be eligible for inclusion in this rapid scoping review. ETHICS AND DISSEMINATION: All data will be extracted from published literature. Hence, ethical approval and patient informed consent are not required. The findings of the scoping review will be submitted for publication in a peer-reviewed journal and presentation at international conferences.

Neuroma Treatment With the Acellular Nerve Allograft Reconstruction Technique.

Treatment of a painful neuroma is a challenging problem for both the patient and the providers. Current surgical treatment options typically include excision of the neuroma and stump relation. However, with both treatment options, patients have high rates of persistent pain and rates of neuroma recurrence. We describe two patients with neuromas treated with our acellular nerve allograft reconstruction technique. This technique involves the excision of the neuroma and bridging the proximal nerve end to the surrounding tissue with an acellular nerve allograft. Both patients had immediate resolution of their neuropathic pain that was maintained at their final follow-up. Acellular nerve allograft reconstruction is a promising treatment option for the treatment of painful neuromas.

Complication Rates and Utilization Trends of 3-Level Posterior Column Osteotomy Compared to Single-Level Pedicle Subtraction Osteotomy.

OBJECTIVE: The objective of this study is to assess differences in complication profiles between 3-level posterior column osteotomy (PCO) and single-level pedicle subtraction osteotomy (PSO) as both are reported to provide similar degrees of sagittal correction. METHODS: The PearlDiver database was queried retrospectively using International Classification of Disease, 9th and 10th edition and Current Procedural Terminology codes to identify patients who underwent PCO or PSO for degenerative spine disease. Patients under age 18 or with history of spinal malignancy, infection, or trauma were excluded. Patients were separated into 2 cohorts, 3-level PCO or single-level PSO, matched at a 1:1 ratio based on age, sex, Elixhauser comorbidity index, and number of fused posterior segments. Thirtyday systemic and procedure-related complications were compared. RESULTS: Matching resulted in 631 patients for each cohort. PCO patients had decreased odds of respiratory (odds ratio [OR], 0.58; 95% confidence interval [CI], 0.43-0.82; p = 0.001) and renal complications (OR, 0.59; 95% CI, 0.40-0.88; p = 0.009) compared to PSO patients. There was no significant difference in cardiac complications, sepsis, pressure ulcer, dural tear, delirium, neurologic injuries, postoperative hematoma, postoperative anemia, or overall complications. CONCLUSION: Patients who undergo 3-level PCO have decreased respiratory and renal complications compared to single-level PSO. No differences were found in the other complications studied. Considering both procedures achieve similar sagittal correction, surgeons should be aware that 3-level PCO offers an improved safety profile compared to single-level PSO.

Effects of cell seeding technique and cell density on BMP-2 production in transduced human mesenchymal stem cells.

Small animal models have demonstrated the efficacy of ex vivo regional gene therapy using scaffolds loaded with BMP-2-expressing mesenchymal stem cells (MSCs). Prior to clinical translation, optimization of seeding techniques of the transduced cells will be important to minimize time and resource expenditure, while maximizing cell delivery and BMP-2 production. No prior studies have investigated cell-seeding techniques in the setting of transduced cells for gene therapy applications. Using BMP-2-expressing transduced adipose-derived MSCs and a porous ceramic scaffold, this study compared previously described static and dynamic seeding techniques with respect to cell seeding efficiency, uniformity of cell distribution, and in vitro BMP-2 production. Static and negative pressure seeding techniques demonstrated the highest seeding efficiency, while orbital shaking was associated with the greatest increases in BMP-2 production per cell. Low density cell suspensions were associated with the highest seeding efficiency and uniformity of cell distribution, and the greatest increases in BMP-2 production from 2 to 7 days after seeding. Our results highlight the potential for development of an optimized cell density and seeding technique that could greatly reduce the number of MSCs needed to produce therapeutic BMP-2 levels in clinical situations. Further studies are needed to investigate in vivo effects of cell seeding techniques on bone healing.

Improving Lentiviral Transduction of Human Adipose-Derived Mesenchymal Stem Cells.

Lentiviral transduction of human mesenchymal stem cells (MSCs) induces long-term transgene expression and holds great promise for multiple gene therapy applications. Polybrene is the most commonly used reagent to improve viral gene transfer efficiency in laboratory research; however, it is not approved for human use and has also been shown to impair MSC proliferation and differentiation. Therefore, there is a need for optimized transduction protocols that can also be adapted to clinical settings. LentiBOOST (LB) and protamine sulfate are alternative transduction enhancers (TEs) that can be manufactured to current Good Manufacturing Practice standards, are easily applied to existing protocols, and have been previously studied for the transduction of human CD34+ hematopoietic stem cells. In this study, we investigated these reagents for the enhancement of lentiviral transduction of adipose-derived MSCs. We found that the combination of LB and protamine sulfate could yield comparable or even superior transduction efficiency to polybrene, with no dose-dependent adverse effects on cell viability or stem cell characteristics. This combination of TEs represents a valuable clinically compatible alternative to polybrene with the potential to significantly improve the efficiency of lentiviral transduction of MSCs for gene therapy applications.