Predictive Value of Teratospermia During Initial Sperm Analysis on the Success of Intrauterine Insemination Cycles.

OBJECTIVE: To evaluate the predictive value of sperm morphology, specifically teratospermia, seen during initial semen analysis on the success of intrauterine insemination (IUI) cycles and pregnancy outcomes. METHODS: A retrospective cohort analysis on patients undergoing IUI at a large US fertility network. Baseline demographic characteristics, primary infertility diagnoses, and pregnancy outcomes were recorded. A total of 27,925 IUI cycles in 16,169 unique patients were analyzed. IUI cycles were grouped by a sperm morphology of 1% (n=3,799), 2% (n=5,506), 3% (n=4,857), or 4% or greater (n=13,763). The outcome measures were pregnancy rate (positive pregnancy test), clinical pregnancy rate (ultrasound confirmation of a gestational sac with a yolk sac around 5-6 weeks), live birth rate, and miscarriage rate. RESULTS: Sperm morphology is a significant predictor of pregnancy rate (p= <0.001), clinical pregnancy rate (p=0.011), and live birth rate (p=0.026) following IUI. In each of these outcome measures, patients with 1% normal forms had the lowest percentage of success, and patients with 4% or greater normal forms had the most success. Relative outcome percentages, however, were similar in each group. Live birth rates in the 1%, 2%, 3% and > 4% group were 12.3%, 13.1%, 12.7% and 13.9%, respectively. Sperm morphology is not a significant predictor of miscarriage rate per clinical pregnancy post IUI (p=0.054). CONCLUSIONS: Sperm morphology was a statistically significant predictor of pregnancy, clinical pregnancy, and live birth but not miscarriage rate after an IUI cycle. Higher morphology percentages were associated with increasingly favorable outcomes. However, the small observed differences did not demonstrate clinical significance.

An intense electrical stimulus can elicit a StartReact effect but with decreased incidence and later onset of the startle reflex.

Planned actions can be triggered involuntarily by a startling acoustic stimulus (SAS), resulting in very short reaction times (RT). This phenomenon, known as the StartReact effect, is thought to result from the startle-related activation of reticular structures. However, other sensory modalities also can elicit a reflexive startle response. Here, we assessed the effectiveness of an intense startling electric stimulus (SES) in eliciting the StartReact effect as compared to a SAS. We tested SES intensities at 15 and 25 times the perceptual threshold of each participant, as well as SAS intensities of 114 dB and 120 dB. The electrical stimulation electrodes were placed over short head of the biceps brachii on the arm not involved in the task. Intense electric and acoustic stimuli were presented on 20% of the trials in a simple RT paradigm requiring a targeted ballistic wrist extension movement. The proportion of trials showing short latency (≤ 120 ms) startle reflex-related activation in sternocleidomastoid was significantly lower on intense electrical stimulus trials compared to intense acoustic trials, and the startle response onset occurred significantly later on SES trials compared to SAS. However, when a startle reflex was observed, RTs related to the prepared movement were facilitated to a similar extent for both SES and SAS conditions, suggesting that the accelerated response latency associated with the StartReact effect is independent of stimulus type.

Switching between task control modes incurs greater reprogramming costs than programming the response de novo.

When performing synchronous hand and foot movements, the way the limbs are synchronized differs depending on the mode of control. When performed in a reaction time (RT) paradigm (reactive control), EMG onsets become synchronized resulting in asynchronous displacement onset. However, when the same movement is performed as an anticipation-timing task (predictive control), displacement onset is synchronized by unconsciously introducing a small delay between EMG onsets. The present experiment investigated the reprogramming costs associated with switching between predictive and reaction control modes. Participants (N = 12, 6F) were asked to simultaneously lift their right heel and right hand in an anticipation-timing task when a rotating clock hand reached a specified target. On some trials, an auditory stimulus was presented either 250 ms or 500 ms before the target and participants were instructed to execute the synchronous movement as quickly as possible after the signal (i.e., switch to reactive mode). Results showed that when the auditory stimulus was delivered 250 ms before the target, participants were unable to switch to a reactive control mode but did switch when the auditory stimulus was presented 500 ms before the target. As expected, the RT on switch trials was substantially longer (∼230 ms) than a simple RT control condition but was also significantly longer (∼130 ms) than a choice RT control condition. These results indicate that switching between control modes for a task involving the same musculature incurs reprogramming costs that are even greater than the time required to program the response de novo.

Nuclear Receptor Corepressors NCOR1 and SMRT Regulate Metabolism via Intestinal Regulation of Carbohydrate Transport.

Nuclear receptor action is mediated in part by the nuclear receptor corepressor 1 (NCOR1) and the silencing mediator of retinoic acid and thyroid hormone receptor (SMRT). NCOR1 and SMRT regulate metabolic pathways that govern body mass, insulin sensitivity and energy expenditure representing an understudied area in the realm of metabolic health and disease. Previously, we found that NCOR1 and SMRT are essential for maintaining metabolic homeostasis and their knockout (KO) leads to rapid weight loss and hypoglycemia, which is not survivable. Because of a potential defect in glucose absorption, we sought to determine the role of NCOR1 and SMRT specifically in intestinal epithelial cells (IECs). We used a post-natal strategy to disrupt NCOR1 and SMRT throughout IECs in adult mice. These mice were characterized metabolically and underwent metabolic phenotyping, body composition analysis and glucose tolerance testing. Jejunal IECs were isolated and profiled by bulk RNA sequencing. We found that the post-natal KO of NCOR1 and SMRT from IECs leads to rapid weight loss and hypoglycemia with a significant reduction in survival. This was accompanied by alterations in glucose metabolism and activation of fatty acid oxidation in IECs. Metabolic phenotyping confirmed a reduction in body mass driven by a loss of body fat without altered food intake. This appeared to be mediated by a reduction of key intestinal carbohydrate transporters, including SGLT1, GLUT2 and GLUT5. Intestinal NCOR1 and SMRT act in tandem to regulate glucose levels and body weight. This in part may be mediated by regulation of intestinal carbohydrate transporters.

Academic Productivity at Orthopedic Spine Surgery Fellowships is Positively Correlated With Nonresearch Lifetime Industry Earnings: A Retrospective Study.

STUDY DESIGN: Retrospective Analysis. OBJECTIVE: The objective of the study was to assess the impact of academic productivity at both individual and program levels on lifetime industry earnings within US orthopedic spine fellowships. SUMMARY OF BACKGROUND DATA: Physician-industry transparency was codified by the Physician Payments Sunshine Act (PSSA) in 2010. No study has explored the relationship between academic productivity and industry earnings at the fellowship level. METHODS: Inclusion criteria encompassed physicians with complete academic and industry data from orthopedic spine fellowship programs listed on the North American Spine Society (NASS) 2022-2023 fellowship directory. Academic productivity was defined via H-index on the Scopus website, and industry productivity by total lifetime earnings on the Open Payments Database (OPD). RESULTS: This analysis included 75 orthopedic spine fellowship programs with 320 individual physicians. Median individual physician lifetime earnings were $86,852.71 (mean: $666,580.23 ± $1,887,734.64; minimum-maximum: $10.86-$27,164,431.49) and the median individual physician (n=320 physicians) H-index was 17.0 (mean: 21.82 ± 19.28; minimum-maximum: 0-109). Median combined physician H-index per fellowship (n=75 fellowships) was 65.0 (mean: 93.08 ± 85.67; minimum-maximum: 3-434) and median combined physician lifetime earnings was $927,771.60 (mean: $2,844,075.64 ± $4,942,089.56; minimum-maximum: $1,112.32-$29,983,900.69). A positive correlation was observed between academic productivity and industry productivity at an individual level (P<0.001; Spearman's rho = 0.467). This correlation was stronger at the fellowship level (P<0.001; Spearman's rho = 0.734). There was no significant difference in total lifetime earnings (P=0.369) or H-index per fellowship (P=0.232) when stratified by region of the fellowship program in the United States. CONCLUSION: Orthopedic spine surgery fellowship programs in the United States exhibit a positive correlation between academic productivity and nonresearch industry lifetime earnings at both individual and program levels. This correlation is stronger at the program level, and regional differences among fellowship programs do not significantly impact academic or industry productivity.

Skin color reporting in basal cell carcinoma-related randomized controlled trials in top dermatology journals: a systematic review.

OBJECTIVES: To determine the rate skin color is reported in randomized controlled trials (RCTs) involving basal cell carcinoma (BCC) identification and treatment in the top ten dermatology journals. METHODS: A systematic review was conducted of RCTs involving BCC among the top ten dermatology journals, determined by impact factor, from inception to July 11th, 2023. Studies were included if they reviewed the prevention, detection, and treatment of BCC, directly involved patients, and were classified as RCTs. Studies were classified as positive for reporting skin of color (SOC) if the demographic data in the methods or results included any of the following terms: Fitzpatrick scale, race, ethnicity, skin of color, or sunburn tendency. RESULTS: Of the 51 studies identified, only 23 articles reported data pertaining to skin color within the results section (45.1%); whereas 28 articles mentioned skin color somewhere within the text (54.9%). Subgroup analysis was performed, and no statistical significance was found for study location or year of publication. CONCLUSION: Dark skin color can make it more difficult to diagnose skin tumors and it is unknown if race affects response to treatment. Less than 50% of RCTs related to basal cell carcinoma in top international dermatology journals included skin color within the demographic portion of their results section pertaining to study participants. Subgroup analysis demonstrated that studies performed within the United States reported skin color less than half the time (40%). Additionally, there has been no statistically significant difference in reporting over the past 4 decades. Further research is necessary to determine whether low reporting rates of race/skin color in BCC-related RCTS could impact diagnostic or treatment recommendations for patient care in this group.

ACL Repair with Suture Tape Augmentation of Proximal Tears and Early ACL Reconstruction with Suture Tape Augmentation Result in Comparable Clinical Outcomes to ACL Reconstruction at 2-year Follow-up.

PURPOSE: The purpose of this study is to compare the post-operative side-to-side laxity and short-term clinical outcomes of patients who received primary ACL repair with suturetape augmentation, acute ACL reconstruction with suture tape augmentation performed within 8 weeks of injury (ACLRacute), or ACL reconstruction (ACLR) beyond 8 weeks of injury. METHODS: Following IRB approval, 100 patients were enrolled in this prospective trial: n=34 primary ACL repair with suture tape augmentation, n=33 ACL reconstruction performed within 8 weeks of injury (ACLRacute), and n=33 ACL Reconstruction (ACLR). Patients were allocated to ACL repair if a proximal avulsion was present with good tissue quality (Sherman type 1), confirmed by intraoperative diagnostic arthroscopy. Preoperative side-to-side AP knee laxity was assessed with KT-1000 arthrometer and patient-reported outcomes (PROs) including visual analog scale (VAS), Marx activity scale, Veterans RAND 12-item health survey (VR-12 physical & mental), Single Assessment Numeric Evaluation (SANE), Knee Injury and Osteoarthritis Outcome Score (KOOS) survey subscales, and range of motion (ROM) were collected. These objective and subjective measures were repeated at regular intervals post-operatively through 2 years. Minimal clinically important differences (MCID) calculations were performed assessing post-operative PRO changes at 2 years compared to preoperative. RESULTS: The average time from injury to surgery was 5.03±1.2 weeks for the ACL repair group, 5.09±0.74 weeks for the ACLRacute, and 43.22±33.5 weeks for the ACLR group. Postoperatively, the KT-1000 side-to-side laxity difference for 30lbs was determined to be 0.1±0.37, 95% CI: [-0.7,0.8] for ACL repair vs ACLR (p<0.0001), -0.8±0.35, 95% CI: [-1.5,-0.1] for ACLRacute vs ACLR (p<0.0001), and 0.8±0.40, 95% CI: [0.0,1.6] for ACL repair vs ACLRacute (p<0.0001). The data reveals ACL repair and ACLRacute are non-inferior to ACLR at 2-year follow-up. The post-operative difference from baseline for all PROs demonstrated improvement for all PROs. MRI at 1-year revealed tissue healing for the three ACL injury treatment groups. CONCLUSION: Patients who underwent ACL repair of proximal tears with suture tape augmentation or ACL reconstruction within 8 weeks from injury resulted in non-inferior side-to-side knee laxity, comparable PROs, and similar range of motion at 2-year follow-up, compared to ACL reconstruction.

Flp/FRT-mediated disruption of ptex150 and exp2 in Plasmodium falciparum sporozoites inhibits liver-stage development.

Plasmodium falciparum causes severe malaria and assembles a protein translocon (PTEX) complex at the parasitophorous vacuole membrane (PVM) of infected erythrocytes, through which several hundred proteins are exported to facilitate growth. The preceding liver stage of infection involves growth in a hepatocyte-derived PVM; however, the importance of protein export during P. falciparum liver infection remains unexplored. Here, we use the FlpL/FRT system to conditionally excise genes in P. falciparum sporozoites for functional liver-stage studies. Disruption of PTEX members ptex150 and exp2 did not affect sporozoite development in mosquitoes or infectivity for hepatocytes but attenuated liver-stage growth in humanized mice. While PTEX150 deficiency reduced fitness on day 6 postinfection by 40%, EXP2 deficiency caused 100% loss of liver parasites, demonstrating that PTEX components are required for growth in hepatocytes to differing degrees. To characterize PTEX loss-of-function mutations, we localized four liver-stage Plasmodium export element (PEXEL) proteins. P. falciparum liver specific protein 2 (LISP2), liver-stage antigen 3 (LSA3), circumsporozoite protein (CSP), and a Plasmodium berghei LISP2 reporter all localized to the periphery of P. falciparum liver stages but were not exported beyond the PVM. Expression of LISP2 and CSP but not LSA3 was reduced in ptex150-FRT and exp2-FRT liver stages, suggesting that expression of some PEXEL proteins is affected directly or indirectly by PTEX disruption. These results show that PTEX150 and EXP2 are important for P. falciparum development in hepatocytes and emphasize the emerging complexity of PEXEL protein trafficking.

The Association of Preoperative Bone Mineral Density and Outcomes after Anterior Cervical Discectomy and Fusion: A Systematic Review.

STUDY DESIGN: This is a systematic review. OBJECTIVE: To evaluate anterior cervical discectomy and fusion (ACDF) outcomes and complications as a function of preoperative bone mineral density (BMD). SUMMARY OF BACKGROUND DATA: Preoperative BMD optimization is commonly initiated before lumbar spinal fusion, but the effects of BMD on ACDF are less known. Consequently, it remains unclear whether preoperative BMD optimization is recommended before ACDF. METHODS: This systematic review included relevant clinical articles using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched PubMed, Web of Science, SCOPUS, and MEDLINE from database inception until October 1, 2023. Eligible studies included those evaluating low BMD and outcomes after ACDF. All articles were graded using the Methodological Index for Non-Randomized Studies (MINORS) scale and Critical Appraisal Skills Programme (CASP) assessment tools. RESULTS: The initial retrieval yielded 4271 articles for which 4 articles with 671 patients were included in the final analysis. The mean patient age was 56.4 ± 3.9 years, and 331 patients (49.3%) were female. A total of 265 (39.5%) patients had low BMD (T score<-1.0) before ACDF. Preoperative low BMD was associated with cage subsidence in single-level ACDF (odds ratio (OR) 2.57; P=0.063; 95% Confidence Interval (CI): 0.95-6.95), but this result did not reach statistical significance. Osteoporosis (T score<-2.5) was associated with the development of adjacent segment disease following ACDF (OR 4.41; P<0.01; 95% CI: 1.98-9.83). Low pre-operative BMD was associated with reoperation within 2 years (P<.05) and strongly associated with pseudarthrosis (OR: 11.01; P=0.002; 95% CI 2.4-49.9). CONCLUSIONS: Patients with low BMD who undergo ACDF have higher rates of subsidence, adjacent segment disease, and pseudarthrosis than those with normal BMD. Given the individual and system-wide burdens associated with these complications, some patients may benefit from preoperative BMD screening and optimization before undergoing ACDF.

Assessment of Strength and Power Capacities in Elite Male Soccer: A Systematic Review of Test Protocols Used in Practice and Research.

BACKGROUND: Strength and power represent two crucial physical qualities for the attainment of a high level of performance considering the frequency and the importance of explosive actions occurring during elite soccer match-play. Evaluation of strength and power is a multifaceted concept involving a vast array of tests and outcome variables. Nevertheless, a comprehensive and systematic search of strength and power assessment procedures in elite soccer has yet to be undertaken. OBJECTIVES: The aims of this systematic review were to: (1) identify the tests and outcome variables used to assess strength and power of elite male soccer players; (2) provide normative values for the most common tests of strength and power across different playing levels; and (3) report the reliability values of these strength and power tests. METHODS: A systematic review of the academic databases MEDLINE, CINAHL, SPORTDiscus, Web of Science and OVID for studies published until August 2023 was conducted, following the Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were eligible for inclusion if they: (1) were original research studies, published in a peer-reviewed journal, and written in English language; (2) had the primary aim to assess strength and/or power; (3) players were male and older than 17 years of age (i.e., mean age of the group); and (4) their playing level was defined as "professional", "international" or "elite". RESULTS: Regarding strength testing, 115 studies and 29 different tests were identified. The three most frequent strength tests were the knee extensor isokinetic strength test (58 studies), the knee flexor isokinetic strength test (55 studies) and the Nordic hamstring strength test (13 studies). In terms of power testing, 127 studies with 31 different tests were included. The three most frequent power tests were the countermovement jump with hands fixed on hips (99 studies), the squat jump (48 studies) and the vertical jump with arm swing (29 studies). CONCLUSIONS: The wide range of different tests and outcome variables identified in this systematic review highlights the large diversity in the employed testing procedures. The establishment of a hybrid testing approach, combining standardised and widely accepted tests for establishing normative standards and enabling comparisons across different contexts, with flexible context-specific testing batteries, has the potential to maximise the impact of testing information for practitioners. In addition, the limited reporting of reliability data across studies highlights the need for practitioners to establish their own reliability measure within their specific contexts, informing the selection of certain tests and outcome variables.

Assessing extremely negative online patient reviews and complaints of musculoskeletal oncology surgeons in the United States: a retrospective analysis.

INTRODUCTION: Physician-review websites (PRWs) are commonly used by patients while searching for a surgeon. There is no current literature investigating the factors that contribute to online one-star reviews of musculoskeletal oncology surgeons. This retrospective study aims to identify these factors to determine areas of care affecting patient's subjective reviews. METHODS: Patient ratings and comments regarding musculoskeletal oncology surgeons from the Musculoskeletal Tumor Society (MSTS) were collected from Vitals.com. One-star reviews with comments were then classified as either operative or nonoperative. These complaints were then further classified based on content including wait time, uncontrolled pain, time spent with the physician, surgical outcomes, medical staff/institutional complaints, and bedside manner. RESULTS: A total of 169 reviews (375 complaints) from 181 physicians were included. Of these complaints, 198 were from patients in the operative category while 177 were from patients in the nonoperative category. Bedside manner was the most common complaint. Operative patients reported higher instances of uncontrolled pain in their reviews, whereas nonoperative patients more frequently cited wait time. No significant difference in the complaints that mentioned the amount of time spent with the physician, bedside manner, a disagreement with the plan, or the medical staff or institution was found. CONCLUSION: Online one-star reviews of musculoskeletal oncology surgeons on Vitals.com referenced both surgical and non-surgical aspects of patient encounters, with bedside manner being the most popular complaint overall. Surgical patients were more likely to complain of uncontrolled pain whereas non-operative patients were more likely to complain of wait time. TYPE OF STUDY: Outcomes 2c.

Evidence for thyroid hormone regulation of amygdala-dependent fear-relevant memory and plasticity.

The amygdala is an established site for fear memory formation, and clinical studies suggest involvement of hormone signaling cascades in development of trauma-related disorders. While an association of thyroid hormone (TH) status and mood disorders is established, the related brain-based mechanisms and the role of TH in anxiety disorders are unknown. Here we examine the role that TH receptor (TR, a nuclear transcriptional repressor when unbound and a transcriptional activator when bound to TH) may have in mediating the initial formation of fear memories in the amygdala. We identified mRNA levels of TR and other TH pathway regulatory genes, including thyrotropin-releasing hormone (Trh), transthyretin (Ttr), thyrotropin-releasing hormone receptor (Trhr), type 2 iodothyronine deiodinase (Dio2), mediator complex subunit 12 (Med12/Trap230) and retinoid X receptor gamma (Rxrg) to be altered in the amygdala following Pavlovian fear conditioning. Using TH agonist and antagonist infusion into the amygdala, we demonstrated that this pathway is both necessary and sufficient for fear memory consolidation. Inhibition of TH signaling with the TR antagonist 1-850 decreased fear memory consolidation; while activation of TR with T3 (triiodothyronine) resulted in increased memory formation. Using a systemic hypothyroid mouse model, we found that intra-amygdala infusions of T3 were sufficient to rescue deficits in fear memory. Finally, we demonstrated that T3 was sufficient to activate TR-specific gene pathways in the amygdala. These findings on the role of activity-dependent TR modulation support a model in which local TH is a critical regulator of fear memory-related plasticity in the amygdala.

Experimental observation of cavity-free ice-free isochoric vitrification via combined pressure measurements and photon counting x-ray computed tomography.

Isochoric (constant-volume or volumetrically confined) vitrification has shown potential as an alternative cryopreservation-by-vitrification technique, but the complex processes at play within the chamber are yet poorly characterized, and recent investigations have prompted significant debate around whether a truly isochoric vitrification process (in which the liquid remains completely confined by solid boundaries) is indeed feasible. Based on a recent thermomechanical simulation of a high-concentration Me2SO solution, Solanki and Rabin (Cryobiology, 2023, 111, 9-15.) argue that isochoric vitrification is not feasible, because differential thermal contraction of the solution and container will necessarily drive generation of a cavity, corrupting the rigid confinement of the liquid. Here, we provide direct experimental evidence to the contrary, demonstrating cavity-free isochoric vitrification of a ∼3.5 M vitrification solution by combined isochoric pressure measurement (IPM) and photon-counting x-ray computed tomography (PC-CT). We hypothesize that the absence of a cavity is due to the minimal thermal contraction of the solution, which we support with additional volumetric analysis of the PC-CT reconstructions. In total, this study provides experimental evidence both demonstrating the feasibility of isochoric vitrification and highlighting the potential of designing vitrification solutions that exhibit minimal thermal contraction.

Neuropathological features of pediatric laryngomalacia.

OBJECTIVE: Laryngomalacia is the most common pediatric laryngeal anomaly. The pathophysiology of laryngomalacia is not well defined; the leading hypothesis suggests weak laryngeal tone and neuromuscular discoordination. Only a few studies explored the histopathology of the laryngeal submucosal nerves, with reported nerve hypertrophy. Our study aims to describe the histopathology of submucosal nerves in specimens obtained from children with severe laryngomalacia compared to pediatric cadaveric controls. STUDY DESIGN: Prospective study. SETTINGS: Tertiary care children's hospital. METHODS: Histologic and immunohistochemical sections of supraglottic tissue from 26 children with severe laryngomalacia and six pediatric autopsies were digitally scanned and assessed with image analysis software (QuPath), resulting in the identification and measurement of 4561 peripheral nerves and over 100,000 foci of neurofilaments. RESULTS: Chronic inflammation was noted in all patients. Eosinophils were rare. The mean nerve area and perimeter were significantly smaller for patients with laryngomalacia compared to the control group (1594.0 ± 593.2 µm^2 vs. 2612.1 ± 2824.0 µm^2, p < 0.0001, and 158.8 ± 30.3 µm vs. 217.6 ± 165.0 µm, p < 0.0001). Nerve-per-area unit was significantly greater for patients with laryngomalacia compared to controls (1.39E-05 vs. 6.19 E-06, p = 0.009). The mean area and the number of neurofilaments per total nerve area were similar. Immunohistochemistry for calretinin, a marker for intestinal ganglion cells in Hirschsprung disease, was absent from all specimens. CONCLUSIONS: This series includes a comparison of all identifiable nerve fibers obtained from children with severe laryngomalacia and shows that the mucosal nerves are smaller on average than controls. These findings fail to provide support for significant morphologic peripheral nerve pathology in laryngomalacia.

Advances and challenges in modeling inherited peripheral neuropathies using iPSCs.

Inherited peripheral neuropathies (IPNs) are a group of diseases associated with mutations in various genes with fundamental roles in the development and function of peripheral nerves. Over the past 10 years, significant advances in identifying molecular disease mechanisms underlying axonal and myelin degeneration, acquired from cellular biology studies and transgenic fly and rodent models, have facilitated the development of promising treatment strategies. However, no clinical treatment has emerged to date. This lack of treatment highlights the urgent need for more biologically and clinically relevant models recapitulating IPNs. For both neurodevelopmental and neurodegenerative diseases, patient-specific induced pluripotent stem cells (iPSCs) are a particularly powerful platform for disease modeling and preclinical studies. In this review, we provide an update on different in vitro human cellular IPN models, including traditional two-dimensional monoculture iPSC derivatives, and recent advances in more complex human iPSC-based systems using microfluidic chips, organoids, and assembloids.

Muscle-specific pyruvate kinase isoforms, PKM1 and PKM2, regulate mammalian SWI/SNF proteins and histone 3 phosphorylation during myoblast differentiation.

Pyruvate kinase is a glycolytic enzyme that converts phosphoenolpyruvate and ADP into pyruvate and ATP. There are two genes that encode pyruvate kinase in vertebrates; Pkm and Pkl encode muscle- and liver/erythrocyte-specific forms, respectively. Each gene encodes two isoenzymes due to alternative splicing. Both muscle-specific enzymes, PKM1 and PKM2, function in glycolysis, but PKM2 also has been implicated in gene regulation due to its ability to phosphorylate histone 3 threonine 11 (H3T11) in cancer cells. Here, we examined the roles of PKM1 and PKM2 during myoblast differentiation. RNA-seq analysis revealed that PKM2 promotes the expression of Dpf2/Baf45d and Baf250a/Arid1A. DPF2 and BAF250a are subunits that identify a specific sub-family of the mammalian SWI/SNF (mSWI/SNF) of chromatin remodeling enzymes that is required for the activation of myogenic gene expression during differentiation. PKM2 also mediated the incorporation of DPF2 and BAF250a into the regulatory sequences controlling myogenic gene expression. PKM1 did not affect expression but was required for nuclear localization of DPF2. Additionally, PKM2 was required not only for the incorporation of phosphorylated H3T11 in myogenic promoters but also for the incorporation of phosphorylated H3T6 and H3T45 at myogenic promoters via regulation of AKT and protein kinase C isoforms that phosphorylate those amino acids. Our results identify multiple unique roles for PKM2 and a novel function for PKM1 in gene expression and chromatin regulation during myoblast differentiation.

Inducible gene expression of IκB-kinase ε is dependent on nuclear factor-κB in human pulmonary epithelial cells.

While IκB-kinase-ε (IKKε) induces immunomodulatory genes following viral stimuli, its up-regulation by inflammatory cytokines remains under-explored. Since airway epithelial cells respond to airborne insults and potentiate inflammation, IKKε expression was characterized in pulmonary epithelial cell lines (A549, BEAS-2B) and primary human bronchial epithelial cells grown as submersion or differentiated air-liquid interface cultures. IKKε expression was up-regulated by the pro-inflammatory cytokines, interleukin-1ß (IL-1ß) and tumour necrosis factor-α (TNFα). Thus, mechanistic interrogations in A549 cells were used to demonstrate the NF-κB dependence of cytokine-induced IKKε. Furthermore, chromatin immunoprecipitation in A549 and BEAS-2B cells revealed robust recruitment of the NF-κB subunit, p65, to one 5' and two intronic regions within the IKKε locus (IKBKE). In addition, IL-1ß and TNFα induced strong RNA polymerase 2 recruitment to the 5' region, the first intron, and the transcription start site. Stable transfection of the p65-binding regions into A549 cells revealed IL-1ß- and TNFα-inducible reporter activity that required NF-κB, but was not repressed by glucocorticoid. While critical NF-κB motifs were identified in the 5' and downstream intronic regions, the first intronic region did not contain functional NF-κB motifs. Thus, IL-1ß- and TNFα-induced IKKε expression involves three NF-κB-binding regions, containing multiple functional NF-κB motifs, and potentially other mechanisms of p65 binding through non-classical NF-κB binding motifs. By enhancing IKKε expression, IL-1ß may prime, or potentiate, responses to alternative stimuli, as modelled by IKKε phosphorylation induced by phorbol 12-myristate 13-acetate. However, since IKKε expression was only partially repressed by glucocorticoid, IKKε-dependent responses could contribute to glucocorticoid-resistant disease.

Spinal cord injury-induced metabolic impairment and steatohepatitis develops in non-obese rats and is exacerbated by premorbid obesity.

Impaired sensorimotor functions are prominent complications of spinal cord injury (SCI). A clinically important but less obvious consequence is development of metabolic syndrome (MetS), including increased adiposity, hyperglycemia/insulin resistance, and hyperlipidemia. MetS predisposes SCI individuals to earlier and more severe diabetes and cardiovascular disease compared to the general population, which trigger life-threatening complications (e.g., stroke, myocardial infarcts). Although each comorbidity is known to be a risk factor for diabetes and other health problems in obese individuals, their relative contribution or perceived importance in propagating systemic pathology after SCI has received less attention. This could be explained by an incomplete understanding of MetS promoted by SCI compared with that from the canonical trigger diet-induced obesity (DIO). Thus, here we compared metabolic-related outcomes after SCI in lean rats to those of uninjured rats with DIO. Surprisingly, SCI-induced MetS features were equal to or greater than those in obese uninjured rats, including insulin resistance, endotoxemia, hyperlipidemia, liver inflammation and steatosis. Considering the endemic nature of obesity, we also evaluated the effect of premorbid obesity in rats receiving SCI; the combination of DIO + SCI exacerbated MetS and liver pathology compared to either alone, suggesting that obese individuals that sustain a SCI are especially vulnerable to metabolic dysfunction. Notably, premorbid obesity also exacerbated intraspinal lesion pathology and worsened locomotor recovery after SCI. Overall, these results highlight that normal metabolic function requires intact spinal circuitry and that SCI is not just a sensory-motor disorder, but also has significant metabolic consequences.