Combinatorial model of amyloid ß and tau reveals synergy between amyloid deposits and tangle formation.

AIMS: To illuminate the pathological synergy between Aß and tau leading to emergence of neurofibrillary tangles (NFT) in Alzheimer's disease (AD), here, we have performed a comparative neuropathological study utilising three distinctive variants of human tau (WT tau, P301L mutant tau and S320F mutant tau). Previously, in non-transgenic mice, we showed that WT tau or P301L tau does not form NFT while S320F tau can spontaneously aggregate into NFT, allowing us to test the selective vulnerability of these different tau conformations to the presence of Aß plaques. METHODS: We injected recombinant AAV-tau constructs into neonatal APP transgenic TgCRND8 mice or into 3-month-old TgCRND8 mice; both cohorts were aged 3 months post injection. This allowed us to test how different tau variants synergise with soluble forms of Aß (pre-deposit cohort) or with frank Aß deposits (post-deposit cohort). RESULTS: Expression of WT tau did not produce NFT or altered Aß in either cohort. In the pre-deposit cohort, S320F tau induced Aß plaque deposition, neuroinflammation and synaptic abnormalities, suggesting that early tau tangles affect the amyloid cascade. In the post-deposit cohort, contemporaneous expression of S320F tau did not exacerbate amyloid pathology, showing a dichotomy in Aß-tau synergy based on the nature of Aß. P301L tau produced NFT-type inclusions in the post-deposit cohort, but not in the pre-deposit cohort, indicating pathological synergy with pre-existing Aß deposits. CONCLUSIONS: Our data show that different tau mutations representing specific folding variants of tau synergise with Aß to different extents, depending on the presence of cerebral deposits.

Combining P301L and S320F tau variants produces a novel accelerated model of tauopathy.

Understanding the biological functions of tau variants can illuminate differential etiologies of Alzheimer's disease (AD) and primary tauopathies. Though the end-stage neuropathological attributes of AD and primary tauopathies are similar, the etiology and behavioral outcomes of these diseases follow unique and divergent trajectories. To study the divergent physiological properties of tau variants on a uniform immunogenetic background, we created somatic transgenesis CNS models of tauopathy utilizing neonatal delivery of adeno-associated viruses expressing wild-type (WT) or mutant tau in non-transgenic mice. We selected four different tau variants-WT tau associated with AD, P301L mutant tau associated with frontotemporal dementia (FTD), S320F mutant tau associated with Pick's disease and a combinatorial approach using P301L/S320F mutant tau. CNS-targeted expression of WT and P301L mutant tau results in robust tau hyperphosphorylation without tangle pathology, gradually developing age-progressive memory deficits. In contrast, the S320F variant, especially in combination with P301L, produces an AD-type tangle pathology, focal neuroinflammation and memory impairment on an accelerated time scale. Using the doubly mutated P301L/S320F tau variant, we demonstrate that combining different mutations can have an additive effect on neuropathologies and associated co-morbidities, possibly hinting at involvement of unique functional pathways. Importantly, we also show that overexpression of wild-type tau as well as an FTD-associated tau variant can lead to cognitive deficits even in the absence of tangles. Together, our data highlights the synergistic neuropathologies and associated cognitive and synaptic alterations of the combinatorial tau variant leading to a robust model of tauopathy.

Neurite orientation dispersion and density imaging reveals white matter and hippocampal microstructure changes produced by Interleukin-6 in the TgCRND8 mouse model of amyloidosis.

Extracellular ß-amyloid (Aß) plaque deposits and inflammatory immune activation are thought to alter various aspects of tissue microstructure, such as extracellular free water, fractional anisotropy and diffusivity, as well as the density and geometric arrangement of axonal processes. Quantifying these microstructural changes in Alzheimer's disease and related neurodegenerative dementias could serve to monitor or predict disease course. In the present study we used high-field diffusion magnetic resonance imaging (dMRI) to investigate the effects of Aß and inflammatory interleukin-6 (IL6), alone or in combination, on in vivo tissue microstructure in the TgCRND8 mouse model of Alzheimer's-type Aß deposition. TgCRND8 and non-transgenic (nTg) mice expressing brain-targeted IL6 or enhanced glial fibrillary protein (EGFP controls) were scanned at 8 months of age using a 2-shell, 54-gradient direction dMRI sequence at 11.1 T. Images were processed using the diffusion tensor imaging (DTI) model or the neurite orientation dispersion and density imaging (NODDI) model. DTI and NODDI processing in TgCRND8 mice revealed a microstructure pattern in white matter (WM) and hippocampus consistent with radial and longitudinal diffusivity deficits along with an increase in density and geometric complexity of axonal and dendritic processes. This included reduced FA, mean, axial and radial diffusivity, and increased orientation dispersion (ODI) and intracellular volume fraction (ICVF) measured in WM and hippocampus. IL6 produced a 'protective-like' effect on WM FA in TgCRND8 mice, observed as an increased FA that counteracted a reduction in FA observed with endogenous Aß production and accumulation. In addition, we found that ICVF and ODI had an inverse relationship with the functional connectome clustering coefficient. The relationship between NODDI and graph theory metrics suggests that currently unknown microstructure alterations in WM and hippocampus are associated with diminished functional network organization in the brain.

Combination Therapy Approach to Overcome the Resistance to PI3K Pathway Inhibitors in Gynecological Cancers.

The PI3K signaling pathway plays an essential role in cancer cell proliferation and survival. PI3K pathway inhibitors are now FDA-approved as a single agent treatment or in combination for solid tumors such as renal cell carcinoma or breast cancer. However, despite the high prevalence of PI3K pathway alterations in gynecological cancers and promising preclinical activity in endometrial and ovarian cancer models, PI3K pathway inhibitors showed limited clinical activity in gynecological cancers. In this review, we provide an overview on resistance mechanisms against PI3K pathway inhibitors that limit their use in gynecological malignancies, including genetic alterations that reactivate the PI3K pathway such as PIK3CA mutations and PTEN loss, compensatory signaling pathway activation, and feedback loops causing the reactivation of the PI3K signaling pathway. We also discuss the successes and limitations of recent clinical trials aiming to address such resistance mechanisms through combination therapies.

Gynecologic Cancer InterGroup CA125 response has a high negative predictive value for CHK1 inhibitor RECIST response in recurrent ovarian cancer.

We investigated the association of CA125 response with prognosis and RECIST response/progressive disease (PD) criteria in recurrent high grade serous ovarian cancer (HGSOC) patients treated with a cell cycle checkpoint kinase 1 inhibitor (CHK1i), prexasertib. 81 patients had measurable disease per RECISTv1.1, of which 72 and 70 were measurable by Gynecologic Cancer InterGroup (GCIG) CA125 response and PD criteria, respectively. Univariate and multivariate analyses showed that GCIG CA125 response (n = 32) is associated with improved progression-free survival (PFS) and overall survival (OS) compared to no GCIG CA125 response (n = 40) (median PFS 8.0 vs. 3.5 months [HR: 0.30, 95% CI: 0.18-0.51, p < 0.0001]; median OS 19.8 vs. 10.0 months [HR: 0.38, 95% CI: 0.23-0.64, p < 0.001]) independent of BRCA mutation status, platinum-sensitivity, previous PARP inhibitor therapy, ECOG performance status, and FIGO stage. Notably, GCIG CA125 response had a high negative predictive value (NPV: 93%, 95% CI: 80-98), but poor positive predictive value (PPV: 53%, 95% CI: 35-71) in predicting RECIST response. CA125 PD criteria also showed poor concordance with RECIST PD (PPV 56%, 95% CI: 40-71; NPV 33%, 95% CI: 17-54). Therefore, serum CA125 may be useful as a highly accessible prognostic and predictive biomarker to CHK1i therapy in recurrent HGSOC.

Factors Affecting Holmium Laser Efficiency: Comparison of Laryngeal Mask Airway and Endotracheal Intubation During Ureteroscopy for Renal Stones.

Introduction: Holmium laser lithotripsy is a standard energy source used for treatment of kidney stones during flexible ureteroscopy. Efficiency of laser surgery may be affected by patient and operator characteristics or perioperative management. Here, we sought to examine intraoperative data from patients undergoing high frequency dusting with high-powered holmium laser lithotripsy to evaluate surgical and demographic factors associated with lasing efficiency (LE). Methods: A total of 82 intraoperative reports were analyzed from an ongoing laser lithotripsy clinical trial evaluating the Lumenis Pulse™ 120H holmium laser with renal stones up to 20 mm in diameter with and without Moses 2.0 technology. For each case, the total pause time between lasing activations was corrected to remove lengthy pauses and divided by the total lasing time to calculate an efficiency percentage. This was then compared with patient demographics, anesthesia administration, stone burden, postoperative complications, and stone-free rates using both univariate and multivariate analyses. Results: Of the 82 included patients, 36 received endotracheal tube (ETT) intubation and 46 had a laryngeal mask airway (LMA). Patients with ETT had significantly higher LE (78.7%) compared to those with an LMA (73.3%) in our univariate analysis (p < 0.01) as well as in the multivariate model that adjusted for maximum stone size, number of stones, stone density, and patient body mass index (p < 0.05). There was also significantly higher mean LE in patients with no postoperative complications (76.3%) compared to those with any grade (I-V) Clavien-Dindo complication within 30 days after surgery (70.0%) (p < 0.05). Conclusions: Flexible ureteroscopy and laser lithotripsy cases with higher LE are associated with lower rates of postoperative complications. The data also support the use of ETT over LMA to improve overall LE; however, this remains one consideration among many for choosing anesthesia administration. Clinical Trial Registration number: NCT04505956.

Management of urachal anomalies in pediatric patients: A comparison of treatment strategies between pediatric urology and general surgery.

INTRODUCTION: Persistence of embryonic urachal structures due to a failure of the urachus to involute into the median umbilical ligament is known as a urachal anomaly (UA). UAs may remain asymptomatic or lead to abdominal pain and recurrent infections. Management of UAs in pediatric patients has historically lacked a clear consensus between conservative and surgical management. While both urologists and general surgeons manage this pathology, a comparison of management style and outcomes between these specialties has not been published to our knowledge. OBJECTIVE: To (1) evaluate trends in management of UAs among pediatric urologists and general surgeons across three tertiary care children's hospitals and (2) identify factors that place patients at higher risk for requiring surgery. STUDY DESIGN: All patients diagnosed with a UA from 2016 to 2020 at our multi-site institution were identified by ICD-10 code Q64.4 "malformation of the urachus" and retrospectively reviewed. Patient demographics, treatment specialty, remnant subtype, and management strategy were recorded. Data was dichotomized between both urology and general surgery as well as between surgical and nonsurgical intervention to identify and compare management strategies. RESULTS: Overall, 143 patients diagnosed with UAs were identified. Of these patients, 74 were treated by urology and 69 were treated by general surgery. Patients who were treated by urology were significantly more likely to receive conservative treatment (66.2% treated conservatively vs. 33.8% treated surgically), while patients treated by general surgery were significantly more likely to undergo surgery (84.1% treated surgically vs. 15.9% treated conservatively, p < .0001). Though, urology was more likely to treat patients who presented incidentally (p < .01), and general surgery was more likely to treat patients who presented with an infected remnant (p < .01). Patients of male sex were more likely overall to receive surgery compared to female patients (p < .01). DISCUSSION: Management of UAs by urologists was more conservative than general surgeons. However, both specialties treat distinctly different patient presentations, with urology managing more incidental remnants and general surgery operating on more emergent, infected urachi. Limitations of the study included its retrospective nature and the insufficient reporting of urachal remnant subtypes and presence of infection among patients. CONCLUSIONS: Management strategies of UAs differ among urology and general surgery, but surgical and conservative treatments are necessary to appropriately treat their distinct patient populations. This study provides valuable insight into current practices of UA management and may help to inform future treatment.

No Value Found With Routine Early Postoperative Radiographs after Implant Removal in Pediatric Patients.

BACKGROUND: Implants are routinely removed in pediatric patients. Fracture through the prior implant site is a common worry after implant removal. Early post-implant removal radiographs are routinely used to evaluate the prior implant removal sites and to assess when a patient may return to normal activities. To our knowledge, the value of early, routine postoperative radiographs after elective implant removal in pediatric patients has not been studied. METHODS: A retrospective patient cohort of pediatric patients who had implant removal from an extremity from 2017 to 2019 was used in this study. Data were collected for patient demographics, implant site, reason for primary surgery, complications, number of postoperative radiographs, radiation exposure, cost of imaging, and whether the postoperative plan was changed by imaging. RESULTS: Two hundred ninety patients were included in the study. Postoperative plans were changed only in 0.69% of patients (n = 2) because of abnormal 2-week radiographs and 1.72% (n = 5) because of abnormal 6-week radiographs. However, the event's proportion difference (change of management) was not statically significant ( P = 0.182) between those who had a radiograph obtained and those who did not. The mean follow-up time was 16 months. The mean number of postoperative radiographs obtained was 3.74, the mean cost per radiograph was $103, and the mean postoperative radiation exposure was 1.34 mSv. No fractures were observed after implant removal. DISCUSSION: A retrospective review of the value of early, postoperative radiographs after routine orthopaedic implant removal found that postoperative radiographs at 2 and 6 weeks did not change the postoperative plan for most of the patients. Postoperative radiographs have an average cost of $103, and radiation exposure equal to approximately 6 months of natural background radiation. LEVEL OF EVIDENCE: Level III.

The CHK1 inhibitor prexasertib in BRCA wild-type platinum-resistant recurrent high-grade serous ovarian carcinoma: a phase 2 trial.

The multi-cohort phase 2 trial NCT02203513 was designed to evaluate the clinical activity of the CHK1 inhibitor (CHK1i) prexasertib in patients with breast or ovarian cancer. Here we report the activity of CHK1i in platinum-resistant high-grade serous ovarian carcinoma (HGSOC) with measurable and biopsiable disease (cohort 5), or without biopsiable disease (cohort 6). The primary endpoint was objective response rate (ORR). Secondary outcomes were safety and progression-free survival (PFS). 49 heavily pretreated patients were enrolled (24 in cohort 5, 25 in cohort 6). Among the 39 RECISTv1.1-evaluable patients, ORR was 33.3% in cohort 5 and 28.6% in cohort 6. Primary endpoint was not evaluable due to early stop of the trial. The median PFS was 4 months in cohort 5 and 6 months in cohort 6. Toxicity was manageable. Translational research was an exploratory endpoint. Potential biomarkers were investigated using pre-treatment fresh biopsies and serial blood samples. Transcriptomic analysis revealed high levels of DNA replication-related genes (POLA1, POLE, GINS3) associated with lack of clinical benefit [defined post-hoc as PFS < 6 months]. Subsequent preclinical experiments demonstrated significant cytotoxicity of POLA1 silencing in combination with CHK1i in platinum-resistant HGSOC cell line models. Therefore, POLA1 expression may be predictive for CHK1i resistance, and the concurrent POLA1 inhibition may improve the efficacy of CHK1i monotherapy in this hard-to-treat population, deserving further investigation.

Low-Dose Naltrexone (LDN) for Chronic Pain at a Single Institution: A Case Series.

Purpose: Low-dose naltrexone (LDN) has increased in popularity as a non-opioid medication that may decrease chronic pain symptoms. LDN is most commonly used to treat fibromyalgia, complex regional pain syndrome (CRPS), and painful diabetic neuropathy. Other studies suggest that LDN provides general symptom reduction in inflammatory conditions such as Crohn's disease and multiple sclerosis. We reviewed our experience with patients to whom we have prescribed LDN to see what types of painful conditions were most responsive to LDN in our patient population. Patients and Methods: Charts from patients who came to the Pain Center between 2014 and 2021 were reviewed. Results: Of the n = 137 patients who were prescribed LDN, 44% had no evidence of ever filling the prescription, and 4.4% of the responses were not charted. Of the remaining who took LDN (n = 70), 64% had some relief and were designated as 'Responders'. The most common pain diagnosis was neuropathic pain which, when added to the diagnosis of complex regional pain syndrome, accounted for 51% of responders to LDN. Patients who experienced greater than 50% pain relief from LDN were more likely to have the diagnosis of neuropathic pain or complex regional pain syndrome (p = 0.038, Fisher's Exact Test). There was a significant difference in the diagnosis of patients who responded to LDN. Patients with spondylosis were much less likely to respond to LDN when compared with other diagnoses (p = 0.00435, Chi-Square Test). Conclusion: Patients with all types of neuropathic pain, including CRPS, were significantly more likely to have pain relief from LDN than patients with spondylosis (p=0.018). The diagnosis of spondylosis was more often associated with a lack of response to LDN than any other diagnosis. Patients may need to have a trial of several weeks before analgesic effects are seen with LDN.

Deletion of Abi3/Gngt2 influences age-progressive amyloid ß and tau pathologies in distinctive ways.

BACKGROUND: The S209F variant of Abelson Interactor Protein 3 (ABI3) increases risk for Alzheimer's disease (AD), but little is known about its function in relation to AD pathogenesis. METHODS: Here, we use a mouse model that is deficient in Abi3 locus to study how the loss of function of Abi3 impacts two cardinal neuropathological hallmarks of AD-amyloid ß plaques and tau pathology. Our study employs extensive neuropathological and transcriptomic characterization using transgenic mouse models and adeno-associated virus-mediated gene targeting strategies. RESULTS: Analysis of bulk RNAseq data confirmed age-progressive increase in Abi3 levels in rodent models of AD-type amyloidosis and upregulation in AD patients relative to healthy controls. Using RNAscope in situ hybridization, we localized the cellular distribution of Abi3 in mouse and human brains, finding that Abi3 is expressed in both microglial and non-microglial cells. Next, we evaluated Abi3-/- mice and document that both Abi3 and its overlapping gene, Gngt2, are disrupted in these mice. Using multiple transcriptomic datasets, we show that expression of Abi3 and Gngt2 are tightly correlated in rodent models of AD and human brains, suggesting a tight co-expression relationship. RNAseq of the Abi3-Gngt2-/- mice revealed upregulation of Trem2, Plcg2, and Tyrobp, concomitant with induction of an AD-associated neurodegenerative signature, even in the absence of AD-typical neuropathology. In APP mice, loss of Abi3-Gngt2 resulted in a gene dose- and age-dependent reduction in Aß deposition. Additionally, in Abi3-Gngt2-/- mice, expression of a pro-aggregant form of human tau exacerbated tauopathy and astrocytosis. Further, using in vitro culture assays, we show that the AD-associated S209F mutation alters the extent of ABI3 phosphorylation. CONCLUSIONS: These data provide an important experimental framework for understanding the role of Abi3-Gngt2 function and early inflammatory gliosis in AD. Our studies also demonstrate that inflammatory gliosis could have opposing effects on amyloid and tau pathology, highlighting the unpredictability of targeting immune pathways in AD.

IL-10 based immunomodulation initiated at birth extends lifespan in a familial mouse model of amyotrophic lateral sclerosis.

Inflammatory signaling is thought to modulate the neurodegenerative cascade in amyotrophic lateral sclerosis (ALS). We have previously shown that expression of Interleukin-10 (IL-10), a classical anti-inflammatory cytokine, extends lifespan in the SOD1-G93A mouse model of familial ALS. Here we test whether co-expression of the decoy chemokine receptor M3, that can scavenge inflammatory chemokines, augments the efficacy of IL-10. We found that recombinant adeno-associated virus (AAV)-mediated expression of IL-10, alone, or in combination with M3, resulted in modest extension of lifespan relative to control SOD1-G93A cohort. Interestingly neither AAV-M3 alone nor AAV-IL-10 + AAV-M3 extend survival beyond that of the AAV-IL-10 alone cohort. Focused transcriptomic analysis revealed induction of innate immunity and phagocytotic pathways in presymptomatic SOD1-G93A mice expressing IL-10 + M3 or IL-10 alone. Further, while IL-10 expression increased microglial burden, the IL-10 + M3 group showed lower microglial burden, suggesting that M3 can successfully lower microgliosis before disease onset. Our data demonstrates that over-expression of an anti-inflammatory cytokine and a decoy chemokine receptor can modulate inflammatory processes in SOD1-G93A mice, modestly delaying the age to paralysis. This suggests that multiple inflammatory pathways can be targeted simultaneously in neurodegenerative disease and supports consideration of adapting these approaches to treatment of ALS and related disorders.