Long-term Outcomes of Peripheral Artery Disease In Veterans: Analysis of the PEripheral ARtery Disease Long-term Survival Study (PEARLS).

Background: Contemporary research in peripheral artery disease (PAD) remains limited due to lack of a national registry and low accuracy of diagnosis codes to identify PAD patients in electronic health records. Methods & Results: Leveraging a novel natural language processing (NLP) system that identifies PAD with high accuracy using ankle brachial index (ABI) and toe-brachial index (TBI) values, we created a registry of 103,748 patients with new onset PAD patients in the Veterans Health Administration (VHA). Study endpoints include mortality, cardiovascular (hospitalization for acute myocardial infarction or stroke) and limb events (hospitalization for critical limb ischemia or major amputation) and were identified using VA and non-VA encounters. The mean age was 70.6 years; 97.3% were males, and 18.5% self-identified as Black race. The mean ABI value was 0.78 (SD: 0.26) and the mean TBI value was 0.51 (SD: 0.19). Nearly one-third (32.4%) patients were currently smoking and 35.4% formerly smoked. Prevalence of hypertension (86.6%), heart failure (22.7%), diabetes (54.8%), renal failure (23.6%), and chronic obstructive pulmonary disease (35.4%) was high. At 1-year, 9.4% of patients had died. The 1-year incidence of cardiovascular events was 5.6 per 100 patient-years and limb events was 4.5 per 100 patient-years. Conclusions: We have successfully launched a registry of >100,000 patients with a new diagnosis of PAD in the VHA, the largest integrated health system in the U.S. The ncidence of death and clinical events in our cohort is high. Ongoing studies will yield important insights regarding improving care and outcomes in this high-risk group.

Deploying a national clinical text processing infrastructure.

OBJECTIVES: Clinical text processing offers a promising avenue for improving multiple aspects of healthcare, though operational deployment remains a substantial challenge. This case report details the implementation of a national clinical text processing infrastructure within the Department of Veterans Affairs (VA). METHODS: Two foundational use cases, cancer case management and suicide and overdose prevention, illustrate how text processing can be practically implemented at scale for diverse clinical applications using shared services. RESULTS: Insights from these use cases underline both commonalities and differences, providing a replicable model for future text processing applications. CONCLUSIONS: This project enables more efficient initiation, testing, and future deployment of text processing models, streamlining the integration of these use cases into healthcare operations. This project implementation is in a large integrated health delivery system in the United States, but we expect the lessons learned to be relevant to any health system, including smaller local and regional health systems in the United States.

Injection parameters affect cell viability and implant volumes in automated cell delivery for the brain.

The technique of central nervous system cell implantation can affect the outcome of preclinical or clinical studies. Our goal was to evaluate the impact of various injection parameters that may be of consequence during the delivery of solute-suspended cells. These parameters included (1) the type and concentration of cells used for implantation, (2) the rate at which cells are injected (flow rate), (3) the acceleration of the delivery device, (4) the period of time between cell loading and injection into the CNS (delay), and (5) the length and gauge of the needle used to deliver the cells. Neural progenitor cells (NPCs) and bone marrow stromal cells (BMSCs) were injected an automated device. These parameters were assessed in relation to their effect on the volume of cells injected and cell viability. Longer and thinner cannulae and higher cell concentrations were detrimental for cell delivery. Devices and techniques that optimize these parameters should be of benefit.

Manual vs automated delivery of cells for transplantation: accuracy, reproducibility, and impact on viability.

BACKGROUND: Cellular transplantation holds promise for the management of a variety of neurological disorders. However, there is great variability in cell type, preparation methods, and implantation technique, which are crucial to clinical outcomes. OBJECTIVE: We compared manual injection with automated injection using a prototype device to determine the possible value of a mechanized delivery system. METHODS: Neural progenitor cells and bone marrow stromal cells were injected using manual or automated methods. Consistency of injection volumes and cell number and viability were evaluated immediately or 1 day after injection. RESULTS: When cells were delivered as a series of 3 manual injections from the same syringe, the variation in fluid volume was greater than for single manual injections. Automated delivery of a series of 3 injections resulted in a lower variability in the amount of delivery than manual injection for both cell lines (1.2%-2.6% coefficient of variability for automated delivery vs 4.3%-24.0% for manual delivery). The amount delivered from injection 1 to injection 3 increased significantly with manual injections, whereas the amount injected did not vary over the 3 injections for the automated unit. Cell viability 1 day after injection was typically 30% to 40% of the value immediately after injection for the bone marrow stromal cells and 30% to 70% for the neural progenitor cells. There were no significant differences in viability attributed to the method of injection. CONCLUSION: The automated delivery device led to enhanced consistency of volumetric cell delivery but did not improve cell viability in the methods tested. Automated techniques could be useful in standardizing reproducible procedures for cell transplantation and improve both preclinical and clinical research.

Cellular transplantation for the nervous system: impact of time after preparation on cell viability and survival.

OBJECT: Cell transplantation has shown promise for the treatment of various neurological disorders, but the factors that influence cell survival and integration following transplantation are poorly understood. In fact, little is known regarding how simple but potentially critical variables, including the method of cellular preparation and administration, might affect transplant success. The goal of the present study was to determine the impact of time between tissue preparation and implantation on cellular viability. Time can vary with cell preparation, delivery to the operating room, and surgical technique. This study was also designed to evaluate the sensitivity of various methods of assessing implant viability. METHODS: Cell lines of neural progenitor cells and bone marrow stromal cells were generated from healthy adult mice. On the day of experimentation, the cells were collected, suspended in a balanced salt solution, and sequentially assessed for viability for up to 3.5 hours based on their appearance under phase-contrast microscopy, their ability to retain a fluorescent dye, and their attachment to a cultivation surface for 24 hours. RESULTS: When viability was measured based on the ability of cells to retain a fluorescent dye, there was a decrease in viability of 10-15% each hour. Based on the ability of the cells to attach to a culture surface and grow for 24 hours, viability decreased more rapidly at approximately 20% per hour. In addition, only about one-third of the cells judged viable based on phase-contrast microscopy or acute dye retention were found to be viable based on plating, and only 10% of the cells initially judged as viable were still capable of survival after 3 hours in suspension. CONCLUSIONS: The authors' results indicate that that there can be significant losses in viability between preparation and implantation and that more sophisticated methods of evaluation, such as the ability of cells to attach to a substrate and grow, may be required to detect decreases in viability. The time between preparation and implantation will be an important factor in clinical trial design.

Survival of transplanted neural progenitor cells enhanced by brain irradiation.

OBJECT: Authors of previous studies have reported that adult transplanted neural progenitor cells (NPCs) are suitable for brain cell replacement or gene delivery. In this study, the authors evaluated survival and integration of adult rat-derived NPCs after transplantation and explored the potential impact on transplant survival of various mechanical and biological factors of clinical importance. METHODS: Adult female Fischer 344 rats were used both as a source and recipient of transplanted NPCs. Both 9L and RG2 rat glioma cells were used to generate in vivo brain tumor models. On the 5th day after tumor implantation, NPCs expressing green fluorescent protein (GFP) were administered either intravenously (3.5 x 10(7) cells) or by stereotactic injection (1 x 10(4)-1 x 10(6) cells) into normal or tumor-bearing brain. The authors evaluated the effect of delivery method (sharp compared with blunt needles, normal compared with zero-volume needles, phosphate-buffered saline compared with medium as vehicle), delivery sites (intravenous compared with intratumoral compared with intraparenchymal), and pretreatment with an immunosuppressive agent (cyclosporin) or brain irradiation (20-40 Gy) on survival and integration of transplanted NPCs. RESULTS: Very few cells survived when less than 10(5) cells were transplanted. When 10(5) cells or more were transplanted, only previously administered brain irradiation significantly affected survival and integration of NPCs. Although GFP-containing NPCs could be readily detected 1 day after injection, few cells survived 4 days to 1 week unless preceded by whole-brain radiation (20 or 40 Gy in a single fraction), which increased the number of GFP-containing NPCs within the tissue more than fivefold. CONCLUSIONS: The authors' findings indicate that most NPCs, including those from a syngeneic autologous source, do not survive at the site of implantation, but that brain irradiation can facilitate subsequent survival in both normal and tumor-bearing brain. An understanding of the mechanisms of this effect could lead to improved survival and clinical utility of transplanted NPCs.

Heritage of radiosurgical research, current trends and future perspective.

Advances in neuroimaging, stereotactic techniques, and robotic technology in the last decade have significantly expanded the applications of radiosurgery. Radiosurgery has become a preferred management modality for many intracranial tumors such as schwannomas, menigiomas and metastatic tumors. While indications of radiosurgery continue to expand, further investigations are critical to understand the mechanism of biological response of CNS tissues to radiation as well as the potential of long-term adverse effects. The effects and the pathogenesis of biologic effects following radiosurgery may be unique. The need for basic research concerning the radiobiology of high-dose single-fraction ionizing radiation on nervous system tissue is crucial. The development of future applications of radiosurgery will depend upon our understanding of radiobiology of radiosurgery. The present review examines the state of radiobiological investigations into the nature of CNS effects, the newer techniques developed, and the use of radiosurgery as a tool for understanding basic CNS biology.

Glycolytic glioma cells with active glycogen synthase are sensitive to PTEN and inhibitors of PI3K and gluconeogenesis.

Increased glycolysis is characteristic of malignancy. Previously, with a mitochondrial inhibitor, we demonstrated that glycolytic ATP production was sufficient to support migration of melanoma cells. Recently, we found that glycolytic enzymes were abundant and some were increased in pseudopodia formed by U87 glioma (astrocytoma) cells. In this study, we examined cell migration, adhesion (a step in migration), and Matrigel invasion of U87 and LN229 glioma cells when their mitochondria were inhibited with sodium azide or limited by 1% O(2). Cell migration, adhesion, and invasion were comparable, with and without mitochondrial inhibition. Upon discovering that glycolysis alone can support glioma cell migration, unique features of glucose metabolism in astrocytic cells were investigated. The ability of astrocytic cells to remove lactate, the inhibitor of glycolysis, via gluconeogenesis and incorporation into glycogen led to consideration of supportive genetic mutations. Loss of phosphatase and tensin homolog (PTEN) releases glycogenesis from constitutive inhibition by glycogen synthase kinase-3 (GSK3). We hypothesize that glycolysis in gliomas can support invasive migration, especially when aided by loss of PTEN's regulation on the phosphatidylinositol-3 kinase (PI3K)/Akt pathway leading to inhibition of GSK3. Migration of PTEN-mutated U87 cells was studied for release of extracellular lactic acid and support by gluconeogenesis, loss of PTEN, and active PI3K. Lactic acid levels plateaued and phosphorylation changes confirmed activation of the PI3K/Akt pathway and glycogen synthase when cells relied only on glycolysis. Glycolytic U87 cell migration and phosphorylation of GSK3 were inhibited by PTEN transfection. Glycolytic migration was also suppressed by inhibiting PI3K and gluconeogenesis with wortmannin and metformin, respectively. These findings confirm that glycolytic glioma cells can migrate invasively and that the loss of PTEN is supportive, with activated glycogenic potential included among the relevant downstream effects.

Experimental radiobiological investigations into radiosurgery: present understanding and future directions.

LARS LEKSELL BEGAN radiobiological investigations to study the effect of high-dose focused radiation on the central nervous system more than 5 decades ago. Although the effects of radiosurgery on the brain tumor microenvironment are still under investigation, radiosurgery has become a preferred management modality for many intracranial tumors and vascular malformations. The effects and the pathogenesis of biological effects after radiosurgery may be unique. The need for basic research concerning the radiobiological effects of high-dose, single-fraction, ionizing radiation on nervous system tissue is crucial. Information from those studies would be useful in devising strategies to avoid, prevent, or ameliorate damage to normal tissue without compromising treatment efficacy. The development of future applications of radiosurgery will depend on an increase in our understanding of the radiobiology of radiosurgery, which in turn will affect the efficacy of treatment. This article analyzes the current state of radiosurgery research with regard to the nature of central nervous system effects, the techniques developed to increase therapeutic efficacy, investigations into the use of radiosurgery for functional disorders, radiosurgery as a tool for investigations into basic central nervous system biology, and the additional areas that require further investigation.