Assessing Muscular Pain and Ergonomics Among Robotic Surgeons in China: A Validation.

INTRODUCTION: Robotic surgery has transformed minimally invasive procedures, offering precision and efficiency. However, the ergonomic aspects of robotic consoles and their impact on surgeon health remain understudied. This review investigates the burden of ergonomics and muscle fatigue among robotic surgeons in China, comparing the findings to a multinational study. METHODOLOGY: A literature review identified themes related to physical discomfort in robotic surgery. A questionnaire was administered to Chinese robotic surgeons, yielding 40 responses. The study assessed demographic characteristics, surgeon experience, ergonomic practices, reported discomfort, and pain-relief mechanisms. RESULTS: The study revealed that most surgeons experienced shoulder and neck pain, with mixed opinions on whether robotic surgery was the primary cause. Stretching exercises were commonly used for pain relief. Surgeons believed that case volume and surgery duration contributed to discomfort. Comparisons with a multinational study suggested potential demographic and experience-related differences. CONCLUSION: While the study has limitations, including a small sample size and potential translation issues, it underscores the importance of addressing ergonomic concerns and providing proper training to robotic surgeons to ensure their well-being and longevity in the field. Further research with larger cohorts and platform-specific analyses is warranted.

Step-by-step Peritoneal Bladder Flap Bunching (PBFB) technique: an innovative approach following lymph node dissection in robotic radical prostatectomy.

INTRODUCTION: Robot-assisted radical prostatectomy (RARP) has become a popular surgical approach for localized prostate cancer due to its favorable oncological and functional outcomes, as well as lower morbidity. In cases of intermediate- and high-risk prostate cancer, bilateral pelvic lymphadenectomy (PLND) is recommended as an adjunct to RARP (1-3). Despite its benefits, PLND can lead to surgical complications, with postoperative lymphocele formation being the most common. Most postoperative lymphoceles are clinically insignificant with variable incidence, reaching up to 60% of cases 4. However, a small percentage of patients 2-8% may experience symptomatic lymphoceles (SL), which can cause significant morbidity (4, 5). SURGICAL TECHNIQUE: We perform our RARP technique with our standard approach in all patients (6). After vesicourethral anastomosis a modified PF created to prevent symptomatic lymphocele. We start by suturing the peritoneal fold on the right side, medially to the vas deferens, followed by a similar stitch on the left side to approximate the edges in the midline. A running suture bunches the bladder peritoneum from both sides, passing through the pubic bone periosteum to secure it in place (7). This approach keeps the lateral pelvic gutters open for lymphatic drainage, while allowing fluid drainage from the true pelvis into the abdomen. A pelvic ultrasound was done for all patients at 6 weeks post operative, and additional clinical follow-up was carried out at 3 months following surgery. CONSIDERATIONS: We have demonstrated a modified technique of peritoneal flap (PBFB) with an initial decrease in postoperative symptomatic lymphoceles, the technique is feasible, safe, does not add significant morbidity, and does not require a learning curve.

Examining the association between blood-based biomarkers and human post mortem neuropathology in the University of Kentucky Alzheimer's Disease Research Center autopsy cohort.

INTRODUCTION: Clinically, detection of disease-causing pathology associated with Alzheimer's disease (AD) and vascular contributions to cognitive impairment and dementia (VCID) is limited to magnetic resonance imaging and positron emission tomography scans, which are expensive and not widely accessible. Here, we assess angiogenic, inflammatory, and AD-related plasma biomarkers to determine their relationships with human post mortem neuropathology. METHOD: Plasma samples were analyzed using a digital immunoassay and pathological evaluation was performed by University of Kentucky Alzheimer's Disease Research Center neuropathologists. The association of plasma markers with neuropathology was estimated via proportional odds and logistic regressions adjusted for age. RESULTS: Included cases (N = 90) showed increased tau/amyloid beta (Aß)42 ratio, glial fibrillary acidic protein (GFAP), vascular endothelial growth factor A (VEGF-A), and placental growth factor (PlGF) were positively associated with higher level of AD neuropathological change, while higher Aß42/Aß40 ratio was inversely associated. Higher PlGF, VEGF-A, and interleukin 6 were inversely associated with chronic cerebrovascular disease, while Aß42/Aß40 ratio was positively associated. DISCUSSION: Our results provide support for the continued study of plasma biomarkers as a clinical screening tool for AD and VCID pathology.

Impact of Prostate Size on the Functional and Oncological Outcomes of Robot-assisted Radical Prostatectomy.

BACKGROUND AND OBJECTIVE: Robot-assisted radical prostatectomy (RARP) is the main surgical approach for treatment of prostate cancer in the USA. Prostate size is always depicted as a factor affecting the outcomes of RARP as shown by many studies, but these studies are limited to a small number of patients. Our aim was to evaluate functional and oncologic outcomes of RARP across varying prostate size measured as prostate specimen weight. METHODS: A cohort of 14 481 patients who underwent RARP in a single center was divided into four groups according to prostate specimen weight: group 1, <50 g; group 2, 50-100 g; group 3, 100-150 g; and group 4, >150 g. Perioperative and postoperative variables and pathological and functional outcomes were compared among the four groups. Cumulative incidence functions were plotted to visualize the distribution of event-time variables among the groups, and differences were evaluated using the log-rank test. KEY FINDINGS AND LIMITATIONS: Patients with larger prostates (groups 3 and 4) were more likely to have higher prostate-specific antigen (PSA), lower biopsy grade group, and worse baseline urinary and sexual characteristics. Group 4 had lower rates of full nerve-sparing surgery (13.7% vs 38.3%) and lymph node dissection (51.3% vs 71.4%), more pT2 disease (69.8% vs 60.3%), less pT3 disease (30.2% vs 39.7%), and lower rates of positive surgical margins (12.8% vs 19.3%) and biochemical recurrence (5.9% vs 7.5%) than group 1. Finally, we observed differences in functional outcomes among the groups for greater prostate size, and patients in group 4 had worse rates of urinary continence (77.8% vs 89.5%) and recovery of sexual function (70.0% vs 84.1%) than group 1. Our study is limited by its retrospective design. CONCLUSIONS AND CLINICAL IMPLICATIONS: The results demonstrate that in this large cohort of patients, greater prostate size affects multiple outcomes, including the rate of nerve-sparing surgery, potency and continence recovery, and oncological and pathological outcomes. These data will be valuable when counseling patients regarding possible RARP outcomes and the timeline for recovery. PATIENT SUMMARY: Our study shows that prostate size can affect the outcomes of robot-assisted removal of the prostate for patients with prostate cancer. Larger prostate size can be associated with worse functional outcomes after surgery.

Technical and ethical considerations in telesurgery.

Telesurgery, a cutting-edge field at the intersection of medicine and technology, holds immense promise for enhancing surgical capabilities, extending medical care, and improving patient outcomes. In this scenario, this article explores the landscape of technical and ethical considerations that highlight the advancement and adoption of telesurgery. Network considerations are crucial for ensuring seamless and low-latency communication between remote surgeons and robotic systems, while technical challenges encompass system reliability, latency reduction, and the integration of emerging technologies like artificial intelligence and 5G networks. Therefore, this article also explores the critical role of network infrastructure, highlighting the necessity for low-latency, high-bandwidth, secure and private connections to ensure patient safety and surgical precision. Moreover, ethical considerations in telesurgery include patient consent, data security, and the potential for remote surgical interventions to distance surgeons from their patients. Legal and regulatory frameworks require refinement to accommodate the unique aspects of telesurgery, including liability, licensure, and reimbursement. Our article presents a comprehensive analysis of the current state of telesurgery technology and its potential while critically examining the challenges that must be navigated for its widespread adoption.

Peritoneal Flap Following Lymph Node Dissection in Robotic Radical Prostatectomy: A Novel "Bunching" Technique.

BACKGROUND: Pelvic lymph node dissection (PLND) is recommended while performing robot-assisted radical prostatectomy (RARP) for patients with localized intermediate or high-risk prostate cancer. However, symptomatic lymphoceles can occur after surgery, adding significant morbidity to patients. Our objective is to describe a novel Peritoneal Bladder Flap Bunching technique (PBFB) to reduce the risk of clinically significant lymphoceles in patients undergoing RARP and PLND. METHODS: We evaluated 2267 patients who underwent RARP with PLND, dividing them into two groups: Group 1, comprising 567 patients who had the peritoneal flap (PBFB), and Group 2, comprising 1700 patients without the flap; propensity score matching carried out at a 1:3 ratio. Variables analyzed included estimated blood loss (EBL), operative time, postoperative complications, lymphocele formation, and the development of symptomatic lymphocele. RESULTS: The two groups exhibited similar preoperative characteristics after matching. There was no statistically significant difference in the occurrence of lymphoceles between the flap group and the non-flap group, with rates of 24% and 20.9%, respectively (p = 0.14). However, none of the patients in the flap group (0%) developed symptomatic lymphoceles, whereas 2.2% of patients in the non-flap group experienced symptomatic lymphoceles (p = 0.01). CONCLUSION: We have demonstrated a modified technique for a peritoneal flap (PBFB) with the initial elimination of postoperative symptomatic lymphoceles and promising short-term outcomes.

Clinical applications of robotic surgery platforms: a comprehensive review.

Robotic surgery has expanded globally across various medical specialties since its inception more than 20 years ago. Accompanying this expansion were significant technological improvements, providing tremendous benefits to patients and allowing the surgeon to perform with more precision and accuracy. This review lists some of the different types of platforms available for use in various clinical applications. We performed a literature review of PubMed and Web of Science databases in May 2023, searching for all available articles describing surgical robotic platforms from January 2000 (the year of the first approved surgical robot, da Vinci® System, by Intuitive Surgical) until May 1st, 2023. All retrieved robotic platforms were then divided according to their clinical application into four distinct groups: soft tissue robotic platforms, orthopedic robotic platforms, neurosurgery and spine platforms, and endoluminal robotic platforms. Robotic surgical technology has undergone a rapid expansion over the last few years. Currently, multiple robotic platforms with specialty-specific applications are entering the market. Many of the fields of surgery are now embracing robotic surgical technology. We review some of the most important systems in clinical practice at this time.

Oncologic outcomes with and without amniotic membranes in robotic-assisted radical prostatectomy: A propensity score matched analysis.

Objective: Placement of human placenta derived grafts during robotic-assisted radical prostatectomy (RARP) hastens the return of continence and potency. The long-term impact on the oncologic outcomes remains to be investigated. Our objective was to determine the oncologic outcomes of patients with dehydrated human amnion chorion membrane (dHACM) at RARP compared to a matched cohort. Methods: In a referral centre, from August 2013 to October 2019, 599 patients used dHACM in bilateral nerve-sparing RARP. We excluded patients with less than 12 months follow-up, simple prostatectomy, and unilateral nerve-sparing. Patients with dHACM (amnio group) were 529, and were propensity score matched 1:1 to 2465 patients without dHACM (non-amnio group) and a minimum follow-up of 36 months. At the time of RARP, dHACM was placed around the neurovascular bundle in the amnio group. Continuous and categorical variables in matched groups was tested by two-sample Kolmogorov-Smirnov test and Fisher's exact test respectively. Outcomes measured were biochemical recurrence (BCR), adjuvant and salvage therapy rates. Results: Propensity score matching resulted in two groups of 444 patients. Cumulative incidence functions for BCR did not show a difference between the groups (p=0.3). Patients in the non-amnio group required salvage therapy more frequently than the amnio group, particularly after partial nerve-sparing RARP (6.3% vs. 2.3%, p=0.001). Limitations are the absence of prospective randomization. Conclusion: The data suggest that using dHACM does not have a negative impact on BCR in patients. Outcomes of cancer specific and overall survival will require follow-up study to increase our understanding of these grafts' impact on prostate cancer biology.

Muscle fatigue and physical discomfort reported by surgeons performing robotic-assisted surgery: a multinational survey.

Robotic surgery has revolutionized surgical procedures and has provided many advantages over traditional laparoscopic and open surgeries. Despite the benefits, there are concerns about the physical discomfort and injuries that may be experienced by surgeons during robotic surgeries. This study aimed to identify the most common muscle groups implicated in robotic surgeons' physical pain and discomfort. A questionnaire was created and sent to 1000 robotic surgeons worldwide, with a response rate of 30.9%. The questionnaire consisted of thirty-seven multiple-choice questions, three short answer questions, and one multiple-option question pertaining to the surgeon's workload as well as their level of discomfort while and after performing surgery. The primary endpoint was to identify the most common muscle groups implicated in robotic surgeons' physical pain and discomfort. Secondary endpoints were to highlight any correlation between age group, BMI, hours of operation, workout regimen, and significant pain levels. The results showed that the most common muscle groups implicated in physical pain and discomfort were the neck, shoulders, and back, with many of the surgeons attributing their muscular fatigue and discomfort to the ergonomic design of the surgeon console. Despite the level of surgeon comfort the robotic console provides when compared to other conventional forms of surgery, the findings suggest the need for better ergonomic practices during robotic surgeries to minimize physical discomfort and injuries for surgeons.

Impact of thyroid hormone perturbations in adult mice: brain weight and blood vessel changes, gene expression variation, and neurobehavioral outcomes.

Mouse models of hyper- and hypothyroidism were used to examine the effects of thyroid hormone (TH) dyshomeostasis on the aging mammalian brain. 13-14 month-old mice were treated for 4months with either levothyroxine (hyperthyroid) or a propylthiouracil and methimazole combination (PTU/Met; hypothyroid). Hyperthyroid mice performed better on Morris Water Maze than control mice, while hypothyroid mice performed worse. Brain weight was increased in thyroxine-treated, and decreased in PTU/Met-treated animals. The brain weight change was strongly correlated with circulating and tissue T4. Quantitative measurements of microvessels were compared using digital neuropathologic methods. There was an increase in microvessel area in hyperthyroid mice. Hypothyroid mice showed a trend for elevated glial fibrillary acidic protein-immunoreactive astrocytes, indicating an increase in neuroinflammation. Gene expression alterations were associated with TH perturbation and astrocyte-expressed transcripts were particularly affected. For example, expression of Gli2 and Gli3, mediators in the Sonic Hedgehog signaling pathway, were strongly impacted by both treatments. We conclude that TH perturbations produce robust neurobehavioral, pathological, and brain gene expression changes in aging mouse models.

Impact of human placental derivative allografts on functional and oncological outcomes after radical prostatectomy: a literature review.

Post radical prostatectomy (RP) erectile dysfunction and incontinence impacts quality of life for patients. In an objective to hasten the recovery of these functional outcomes, human placental derived allografts laid on neurovascular bundles (NVB) have been investigated. These grafts include amniotic membranes (AM) chorionic membranes (CM) or umbilical cord (UC) allografts. A literature review performed using the MeSH terms "AMNION" OR "CHORION" OR "AMNIOTIC MEMBRANE" OR "UMBILICAL CORD" AND "PROSTATE CANCER" from no specified start date, to April 2022. 163 articles were retrieved, with 149 articles excluded. 14 articles were eligible and analysed. 5 articles were included in this review for an analysis on comparative outcomes. The average return to potency was statistically significant in the intervention groups. Positive surgical margin (PSM) rates showed a higher rate in the control groups. BCR was observed at a lower rate in the interventional group. This review reveals a benefit from human placental allograft's ability to hasten post RP functional recovery, without impacting oncological control.

Association between APOE genotype and microglial cell morphology.

APOE is the largest genetic risk factor for late-onset Alzheimer disease (AD) with E4 conferring an increased risk for AD compared to E3. The ApoE protein can impact diverse pathways in the brain including neuroinflammation but the precise impact of ApoE isoforms on inflammation remains unknown. As microglia are a primary source of neuroinflammation, this study determined whether ApoE isoforms have an impact on microglial morphology and activation using immunohistochemistry and digital analyses. Analysis of ionized calcium-binding adaptor molecule 1 (Iba1) immunoreactivity indicated greater microglial activation in both the hippocampus and superior and middle temporal gyrus (SMTG) in dementia participants versus non-demented controls. Further, only an increase in activation was seen in E3-Dementia participants in the entire SMTG, whereas in the grey matter of the SMTG, only a diagnosis of dementia impacted activation. Specific microglial morphologies showed a reduction in ramified microglia in the dementia group. For rod microglia, a reduction was seen in E4-Control patients in the hippocampus whereas in the SMTG an increase was seen in E4-Dementia patients. These findings suggest an association between ApoE isoforms and microglial morphologies and highlight the importance of considering ApoE isoforms in studies of AD pathology.

Hippocampal sclerosis in advanced age: clinical and pathological features.

Hippocampal sclerosis is a relatively common neuropathological finding (∼10% of individuals over the age of 85 years) characterized by cell loss and gliosis in the hippocampus that is not explained by Alzheimer's disease. Hippocampal sclerosis pathology can be associated with different underlying causes, and we refer to hippocampal sclerosis in the aged brain as hippocampal sclerosis associated with ageing. Much remains unknown about hippocampal sclerosis associated with ageing. We combined three different large autopsy cohorts: University of Kentucky Alzheimer's Disease Centre, the Nun Study and the Georgia Centenarian Study to obtain a pool of 1110 patients, all of whom were evaluated neuropathologically at the University of Kentucky. We focused on the subset of cases with neuropathology-confirmed hippocampal sclerosis (n=106). For individuals aged≥95 years at death (n=179 in our sample), each year of life beyond the age of 95 years correlated with increased prevalence of hippocampal sclerosis pathology and decreased prevalence of 'definite' Alzheimer's disease pathology. Aberrant TAR DNA protein 43 immunohistochemistry was seen in 89.9% of hippocampal sclerosis positive patients compared with 9.7% of hippocampal sclerosis negative patients. TAR DNA protein 43 immunohistochemistry can be used to demonstrate that the disease is usually bilateral even when hippocampal sclerosis pathology is not obvious by haematoxylin and eosin stains. TAR DNA protein 43 immunohistochemistry was negative on brain sections from younger individuals (n=10) after hippocampectomy due to seizures, who had pathologically confirmed hippocampal sclerosis. There was no association between cases with hippocampal sclerosis associated with ageing and apolipoprotein E genotype. Age of death and clinical features of hippocampal sclerosis associated with ageing (with or without aberrant TAR DNA protein 43) were distinct from previously published cases of frontotemporal lobar degeneration TAR DNA protein 43. To help sharpen our ability to discriminate patients with hippocampal sclerosis associated with ageing clinically, the longitudinal cognitive profile of 43 patients with hippocampal sclerosis associated with ageing was compared with the profiles of 75 controls matched for age, gender, education level and apolipoprotein E genotype. These individuals were followed from intake assessment, with 8.2 (average) longitudinal cognitive assessments. A neuropsychological profile with relatively high-verbal fluency but low word list recall distinguished the hippocampal sclerosis associated with ageing group at intake (P<0.015) and also 5.5-6.5 years before death (P<0.005). This may provide a first step in clinical differentiation of hippocampal sclerosis associated with ageing versus pure Alzheimer's disease in their earliest stages. In summary, in the largest series of autopsy-verified patients with hippocampal sclerosis to date, we characterized the clinical and pathological features associated with hippocampal sclerosis associated with ageing.

Evaluating the ability of students to learn and utilize a novel telepresence platform, Proximie.

Novice users of telesurgery could be limited by their experience and technical ability. The impact of the COVID-19 pandemic on health care systems is unprecedented, and telehealth allowed care providers and patients a safety margin. An indirect impact of redeployment of hospital staff during COVID-19 management has been on the reduced educational opportunities for residents. Proximie can be considered as a virtual teaching platform or classroom for any user. Twenty-one students voluntarily participated in utilizing a da Vinci® skills simulator (dVSS) to carry out surgical training simulation tasks. Our study focuses on digital native's adaptation to utilizing Proximie's augmented reality platform to direct task performance, to gauge its feasibility by this unique cohort.

Nerve spare robot assisted laparoscopic prostatectomy with amniotic membranes: medium term outcomes.

INTRODUCTION: dHACM is a source of factors including cytokines that allow anti-inflammatory and proliferative elements to be utilized for wound and ulcer management. We present our experience of using dHACM in a cohort of patients undergoing nerve-sparing (NS) robot-assisted laparoscopic prostatectomy (RALP). Our objective is to investigate the functional and oncological outcomes of NS after placing amniotic or dehydrated human amnion/chorion membrane (dHACM) on preserved neurovascular bundles (NVBs). From 2013 to 2019, our institution performed transperitoneal multi-port da Vinci robotic prostatectomy. The NVBs are spared by releasing their fascial planes posteriorly, followed by an anterior release of the plane at a similar level. Once the retrograde release of the NVB is performed then 599 patients underwent placement of dHACM graft (AmnioFix by MiMedx, Marietta, GA, USA). The graft was cut into two 4 × 1 cm pieces and laid over the NVB as a wrap. In order to inform the urological community of oncological and functional outcomes, we excluded patients with less than 12 months follow up (n = 64), benign prostatic hyperplasia (n = 5), and unilateral NS (n = 1). 529 (88%) patients were included in this study who underwent a partial or full bilateral NS with dHACM. 529 patients were followed-up for a median (IQR) of 42 months (25-89). Demographics include median (IQR) age 57 years (52-62), median preoperative SHIM score of 24 (21-15), and AUASS of 5 (2-11). Full NS was performed in 74% (391/529). Pathological staging was pT2 = 399 (75%), pT3a = 107 (20%), pT3b = 19 (4%) and pT4 = 4 (1%) with N1 = 3 (0.6%). The number of patients with PSM was 86 (16%), and the overall BCR in the entire cohort was 10%. Postoperatively, 434 (82%) were sexually active. Median time to potency was 119 (37-420) days and time to continence was 42 (23-91) days. Regarding full vs partial NS: median post op SHIM score 18 (13-20) vs 15 (6-20), median time to potency 92 (35-365) days vs 184 (42-560) days, and median time to continence 42 (23-91) days vs 44 (30-92) days. Age > 55 vs ≤ 55 years: median post op SHIM score 18 (12-20) vs 15 (10-20), median time to potency 167 days (42-549) vs 80 (35-288) days, and median time to continence 42 (25-116) days vs 42 (29-76) days. In our series the application of amniotic membrane/dHACM has led to acceptable post RALP outcomes. The BCR rate of 10% in addition to the recovery of potency at a median time of 3 months and continence at 6 weeks is an encouraging result of dHACM. Our findings indicate that dHACM allowed for an even faster period for continence recovery which was independent of grade of NS. Future comparative studies may further assess the impact of new amniotic membrane types on the functional and oncological outcomes after RALP.

Genetic expression changes and pathologic findings associated with hyperhomocysteinemia in human autopsy brain tissue.

Introduction: Vascular contributions to cognitive impairment and dementia (VCID) are a leading cause of dementia. An underappreciated, modifiable risk factor for VCID is hyperhomocysteinemia (HHcy), defined by elevated levels of plasma homocysteine, most often due to impaired B vitamin absorption in aged persons. Studies aimed at identifying neuropathologic features and gene expression profiles associated with HHcy have been lacking. Methods: A subset of research volunteers from the University of Kentucky Alzheimer's Disease Research Center longitudinal cohort came to autopsy and had ante mortem plasma homocysteine levels available. Brain tissue and blood plasma drawn closest to death were used to measure homocysteine and related metabolites in the current pilot study. Genetic expression profiles of inflammatory markers were evaluated using the Human Neuroinflammation NanoString panel. Further analyses included an evaluation of plasma homocysteine effects on amyloid beta, tau, ionized calcium-binding adaptor molecule 1, and glial fibrillary acidic protein immunohistochemistry in the frontal and occipital cortices. Analytes and other study outcomes were evaluated in relation to ante mortem HHcy status: We identified 13 persons with normal ante mortem plasma homocysteine levels (<14 µmol/L) and 18 who had high plasma homocysteine levels (≥14 µmol/L). Results: Participants with HHcy demonstrated increased levels of several plasma homocysteine cycle metabolites such as total cysteine, S-adenosyl-homocysteine, cystathionine, and choline. Inflammatory gene expression profiles showed a general downregulation in the setting of elevated plasma homocysteine. HHcy was associated with more and longer microglial processes, but smaller and fewer astrocytes, especially in participants of older age at death. HHcy in older participants was also associated with occipital cortex microhemorrhages and increased severity of atherosclerosis throughout the cerebral vasculature. Conclusions: Increased plasma homocysteine and older age were associated with the downregulation of inflammatory gene expression markers in association with significant glial and vascular pathology changes. Impaired immune function is a plausible mechanism by which HHcy increases cerebrovascular damage leading to impaired cognitive function.

Inflammatory Pathways Are Impaired in Alzheimer Disease and Differentially Associated With Apolipoprotein E Status.

Alzheimer disease (AD) is a neurodegenerative disease characterized by a cognitive decline leading to dementia. The most impactful genetic risk factor is apolipoprotein E (APOE). APOE-ε4 significantly increases AD risk, APOE-ε3 is the most common gene variant, and APOE-ε2 protects against AD. However, the underlying mechanisms of APOE-ε4 on AD risk remains unclear, with APOE-ε4 impacting many pathways. We investigated how the APOE isoforms associated with the neuroinflammatory state of the brain with and without AD pathology. Frozen brain tissue from the superior and middle temporal gyrus was analyzed from APOE-ε3/3 (n = 9) or APOE-ε4/4 (n = 10) participants with AD pathology and APOE-ε3/3 (n = 9) participants without AD pathology. We determined transcript levels of 757 inflammatory related genes using the NanoString Human Neuroinflammation Panel. We found significant pathways impaired in APOE-ε4/4-AD individuals compared to APOE-ε3/3-AD. Of interest, expression of genes related to microglial activation (SALL1), motility (FSCN1), epigenetics (DNMT1), and others showed altered expression. Additionally, we performed immunohistochemistry of P2RY12 to confirm reduced microglial activation. Our results suggest APOE-ε3 responds to AD pathology while potentially having a harmful long-term inflammatory response, while APOE-ε4 shows a weakened response to pathology. Overall, APOE isoforms appear to modulate the brain immune response to AD-type pathology.

Dystrophic microglia are associated with neurodegenerative disease and not healthy aging in the human brain.

Loss of physiological microglial function may increase the propagation of neurodegenerative diseases. Cellular senescence is a hallmark of aging; thus, we hypothesized age could be a cause of dystrophic microglia. Stereological counts were performed for total microglia, 2 microglia morphologies (hypertrophic and dystrophic) across the human lifespan. An age-associated increase in the number of dystrophic microglia was found in the hippocampus and frontal cortex. However, the increase in dystrophic microglia was proportional to the age-related increase in the total number of microglia. Thus, aging alone does not explain the presence of dystrophic microglia. We next tested if dystrophic microglia could be a disease-associated microglia morphology. Compared with controls, the number of dystrophic microglia was greater in cases with either Alzheimer's disease, dementia with Lewy bodies, or limbic-predominant age-related TDP-43 encephalopathy. These results demonstrate that microglia dystrophy, and not hypertrophic microglia, are the disease-associated microglia morphology. Finally, we found strong evidence for iron homeostasis changes in dystrophic microglia, providing a possible molecular mechanism driving the degeneration of microglia in neurodegenerative disease.

Cognitive decline in Alzheimer's disease is associated with selective changes in calcineurin/NFAT signaling.

Upon activation by calcineurin, the nuclear factor of activated T-cells (NFAT) translocates to the nucleus and guides the transcription of numerous molecules involved in inflammation and Ca(2+) dysregulation, both of which are prominent features of Alzheimer's disease (AD). However, NFAT signaling in AD remains relatively uninvestigated. Using isolated cytosolic and nuclear fractions prepared from rapid-autopsy postmortem human brain tissue, we show that NFATs 1 and 3 shifted to nuclear compartments in the hippocampus at different stages of neuropathology and cognitive decline, whereas NFAT2 remained unchanged. NFAT1 exhibited greater association with isolated nuclear fractions in subjects with mild cognitive impairment (MCI), whereas NFAT3 showed a strong nuclear bias in subjects with severe dementia and AD. Similar to NFAT1, calcineurin-Aalpha also exhibited a nuclear bias in the early stages of cognitive decline. But, unlike NFAT1 and similar to NFAT3, the nuclear bias for calcineurin became more pronounced as cognition worsened. Changes in calcineurin/NFAT3 were directly correlated to soluble amyloid-beta (Abeta((1-42))) levels in postmortem hippocampus, and oligomeric Abeta, in particular, robustly stimulated NFAT activation in primary rat astrocyte cultures. Oligomeric Abeta also caused a significant reduction in excitatory amino acid transporter 2 (EAAT2) protein levels in astrocyte cultures, which was blocked by NFAT inhibition. Moreover, inhibition of astrocytic NFAT activity in mixed cultures ameliorated Abeta-dependent elevations in glutamate and neuronal death. The results suggest that NFAT signaling is selectively altered in AD and may play an important role in driving Abeta-mediated neurodegeneration.