Sox9 conditional knockdown reduces chondroitin sulphate proteoglycan expression, increases neuroplasticity, and improves motor function in a mouse model of spinal cord injury

This thesis investigates the effect of Sox9 knockdown on anti-regenerative scar gene expression, neuroplasticity, and hind limb functional recovery following mouse spinal cord injury. We hypothesized that Sox9 knockdown would reduce expression of anti-regenerative chondroitin sulfate proteoglycans both at the lesion site and at sites distant to the injury, thus providing an avenue for increased neuroplasticity and locomotor recovery after spinal cord injury. The first chapter provides a general introduction to the biological problem of spinal cord injury. The development of the glial scar and expression of the anti-regenerative chondroitin sulfate proteoglycan extracellular matrix is introduced, and Sox9 is identified as a transcription factor that may control expression of these anti-regenerative genes. The second chapter is a manuscript that describes the molecular changes and improved locomotor function seen when Sox9 knockdown is carried out just prior to spinal cord injury. The third chapter is more clinically relevant as it is a manuscript detailing the effects of Sox9 knockdown after spinal cord injury on the recovery of hind limb motor function. The fourth chapter is a manuscript investigating the neuro-anatomical mechanism of the improved functional recovery seen in Sox9 knockdown mice after spinal cord injury. The fifth chapter reflects on the findings presented herein, and suggests possible future plans of study. This dissertation demonstrates that inhibition of Sox9 leads to reduced CSPG expression, improved hind limb function, and increased total locomotion. It further provides compelling evidence that increased neuroplasticity as evidenced by increased reactive sprouting and increased expression of the presynaptic markers synaptophysin and VGLUT1 caudal to the injury site underlies the improved neurological recovery observed in spinal cord injured Sox9 conditional knockdown mice

Conditional Sox9 ablation reduces chondroitin sulfate proteoglycan levels and improves motor function following spinal cord injury

Chondroitin sulfate proteoglycans (CSPGs) found in perineuronal nets and in the glial scar after spinal cord injury have been shown to inhibit axonal growth and plasticity. Since we have previously identified SOX9 as a transcription factor that upregulates the expression of a battery of genes associated with glial scar formation in primary astrocyte cultures, we predicted that conditional Sox9 ablation would result in reduced CSPG expression after spinal cord injury and that this would lead to increased neuroplasticity and improved locomotor recovery. Control and Sox9 conditional knock-out mice were subject to a 70 kdyne contusion spinal cord injury at thoracic level 9. One week after injury, Sox9 conditional knock-out mice expressed reduced levels of CSPG biosynthetic enzymes (Xt-1 and C4st), CSPG core proteins (brevican, neurocan, and aggrecan), collagens 2a1 and 4a1, and Gfap, a marker of astrocyte activation, in the injured spinal cord compared with controls. These changes in gene expression were accompanied by improved hind limb function and locomotor recovery as evaluated by the Basso Mouse Scale (BMS) and rodent activity boxes. Histological assessments confirmed reduced CSPG deposition and collagenous scarring at the lesion of Sox9 conditional knock-out mice, and demonstrated increased neurofilament-positive fibers in the lesion penumbra and increased serotonin immunoreactivity caudal to the site of injury. These results suggest that SOX9 inhibition is a potential strategy for the treatment of SCI. © 2012 Wiley Periodicals, Inc

Syncope and Early Repolarization: A Benign or Dangerous ECG Finding?

Early repolarization is a well-described, common electrocardiographic variant. It was initially felt to be benign, but in the last twenty years a suggested a link between specific types of early repolarization and sudden cardiac death has emerged. This association was has been termed the J wave syndrome and includes both the high risk early repolarization and Brugada ECG patterns. The odds of early repolarization change being associated with poor outcomes are still exceedingly small. Nevertheless, the association of a fairly ubiquitous ECG finding with fatal or near fatal clinical outcomes has raised concern. How can we identify the truly high-risk patients? If a patient has a significant clinical event with a concerning ECG repolarization pattern, what should be done next? The authors of this review present current information regarding the Early Repolarization and Brugada Syndromes and how to proceed with diagnosis, management, and risk stratification when early repolarization change is observed on ECG

His Bundle Pacing: Rebirth of an Important Technique for Pacing the Intrinsic Conduction System

Permanent pacemaker implant is a commonly performed cardiac procedure for treatment of bradycardia or conduction system abnormality. With conventional right ventricular (RV) pacing a lead is implanted at the RV apex or on the RV septum. However, RV apical or RV septal pacing causes iatrogenic left bundle-branch block and ventricular dyssynchrony and can lead to adverse cardiac remodeling, a pacing-mediated cardiomyopathy, and congestive heart failure. Alternatively, permanent His-bundle pacing uses the intrinsic rapidly-conducting His-Purkinje system to activate the ventricle, thereby maintaining (or sometimes even restoring) ventricular synchrony. Many patients may derive benefit from permanent His-bundle pacing

Better Than You Think—Appropriate Use of Implantable Cardioverter-Defibrillators at a Single Academic Center: A Retrospective Review

Background: Implantable cardioverter-defibrillators (ICDs) can be life-saving devices, although they are expensive and may cause complications. In 2013, several professional societies published joint appropriate use criteria (AUC) assessing indications for ICD implantation. Data evaluating the clinical application of AUC are limited. Previous registry-based studies estimated that 22.5% of primary prevention ICD implantations were “non-evidence-based” implantations. On the basis of AUC, we aimed to determine the prevalence of “rarely appropriate” ICD implantation at our institution for comparison with previous estimates. Methods: We reviewed 286 patients who underwent ICD implantation between 2013 and 2016. Appropriateness of each ICD implantation was assessed by independent review and rated on the basis of AUC. Results: Of 286 ICD implantations, two independent reviewers found that 89.5% and 89.2%, respectively, were appropriate, 5.6% and 7.3% may be appropriate, and 1.8% and 2.1% were rarely appropriate. No AUC indication was found for 3.5% and 3.4% of ICD implantations, respectively. Secondary prevention ICD implantations were more likely rarely appropriate (2.6% vs. 1.2% and 3.6% vs. 1.1%) or unrated (6.0% vs. 1.2% and 2.7% vs. 0.6%). The reviewers found 3.5% and 3.4% of ICD implantations, respectively, were non-evidence-based implantations. The difference in rates between reviewers was not statistically significant. Conclusion: Compared with prior reports, our prevalence of rarely appropriate ICD implantation was very low. The high appropriate use rate could be explained by the fact that AUC are based on current clinical practice. The AUC could benefit from additional secondary prevention indications. Most importantly, clinical judgement and individualized care should determine which patients receive ICDs irrespective of guidelines or criteria. </p

Lentivirus-mediated gene therapy for Fabry disease

Enzyme and chaperone therapies are used to treat Fabry disease. Such treatments are expensive and require intrusive biweekly infusions; they are also not particularly efficacious. In this pilot, single-arm study (NCT02800070), five adult males with Type 1 (classical) phenotype Fabry disease were infused with autologous lentivirus-transduced, CD34+-selected, hematopoietic stem/progenitor cells engineered to express alpha-galactosidase A (α-gal A). Safety and toxicity are the primary endpoints. The non-myeloablative preparative regimen consisted of intravenous melphalan. No serious adverse events (AEs) are attributable to the investigational product. All patients produced α-gal A to near normal levels within one week. Vector is detected in peripheral blood and bone marrow cells, plasma and leukocytes demonstrate α-gal A activity within or above the reference range, and reductions in plasma and urine globotriaosylceramide (Gb3) and globotriaosylsphingosine (lyso-Gb3) are seen. While the study and evaluations are still ongoing, the first patient is nearly three years post-infusion. Three patients have elected to discontinue enzyme therapy

Binding of Human Milk to Pathogen Receptor DC-SIGN Varies with Bile Salt-Stimulated Lipase (BSSL) Gene Polymorphism

OBJECTIVE: Dendritic cells bind an array of antigens and DC-SIGN has been postulated to act as a receptor for mucosal pathogen transmission. Bile salt-stimulated lipase (BSSL) from human milk potently binds DC-SIGN and blocks DC-SIGN mediated trans-infection of CD4(+) T-lymphocytes with HIV-1. Objective was to study variation in DC-SIGN binding properties and the relation between DC-SIGN binding capacity of milk and BSSL gene polymorphisms. STUDY DESIGN: ELISA and PCR were used to study DC-SIGN binding properties and BSSL exon 11 size variation for human milk derived from 269 different mothers distributed over 4 geographical regions. RESULTS: DC-SIGN binding properties were highly variable for milks derived from different mothers and between samplings from different geographical regions. Differences in DC-SIGN binding were correlated with a genetic polymorphism in BSSL which is related to the number of 11 amino acid repeats at the C-terminus of the protein. CONCLUSION: The observed variation in DC-SIGN binding properties among milk samples may have implications for the risk of mucosal transmission of pathogens during breastfeeding

Novel anti-CD30/CD3 bispecific antibodies activate human T cells and mediate potent anti-tumor activity

CD30 is expressed on Hodgkin lymphomas (HL), many non-Hodgkin lymphomas (NHLs), and non-lymphoid malignancies in children and adults. Tumor expression, combined with restricted expression in healthy tissues, identifies CD30 as a promising immunotherapy target. An anti-CD30 antibody-drug conjugate (ADC) has been approved by the FDA for HL. While anti-CD30 ADCs and chimeric antigen receptors (CARs) have shown promise, their shortcomings and toxicities suggest that alternative treatments are needed. We developed novel anti-CD30 x anti-CD3 bispecific antibodies (biAbs) to coat activated patient T cells (ATCs) ex vivo prior to autologous re-infusions. Our goal is to harness the dual specificity of the biAb, the power of cellular therapy, and the safety of non-genetically modified autologous T cell infusions. We present a comprehensive characterization of the CD30 binding and tumor cell killing properties of these biAbs. Five unique murine monoclonal antibodies (mAbs) were generated against the extracellular domain of human CD30. Resultant anti-CD30 mAbs were purified and screened for binding specificity, affinity, and epitope recognition. Two lead mAb candidates with unique sequences and CD30 binding clusters that differ from the ADC in clinical use were identified. These mAbs were chemically conjugated with OKT3 (an anti-CD3 mAb). ATCs were armed and evaluated in vitro for binding, cytokine production, and cytotoxicity against tumor lines and then in vivo for tumor cell killing. Our lead mAb was subcloned to make a Master Cell Bank (MCB) and screened for binding against a library of human cell surface proteins. Only huCD30 was bound. These studies support a clinical trial in development employing ex vivo-loading of autologous T cells with this novel biAb

HIV-1 Disease Progression Is Associated with Bile-Salt Stimulated Lipase (BSSL) Gene Polymorphism

Background: DC-SIGN expressed by dendritic cells captures HIV-1 resulting in trans-infection of CD4+ T-lymphocytes. However, BSSL (bile-salt stimulated lipase) binding to DC-SIGN interferes with HIV-1 capture. DC-SIGN binding properties of BSSL associate with the polymorphic repeated motif of BSSL exon 11. Furthermore, BSSL binds to HIV-1 co-receptor CXCR4. We hypothesized that BSSL modulates HIV-1 disease progression and emergence of CXCR4 using HIV-1 (X4) variants. Results: The relation between BSSL genotype and HIV-1 disease progression and emergence of X4 variants was studied using Kaplan Meier and multivariate Cox proportional hazard analysis in a cohort of HIV-1 infected men having sex with men (n = 334, with n = 130 seroconverters). We analyzed the association of BSSL genotype with set-point viral load and CD4 cell count, both pre-infection and post-infection at viral set-point. The number of repeats in BSSL exon 11 were highly variable ranging from 10 to 18 in seropositive individuals and from 5-17 in HRSN with 16 repeats being dominant (>80% carry at least one allele with 16 repeats). We defined 16 to 18 repeats as high (H) and less than 16 repeats as low (L) repeat numbers. Homozygosity for the high (H) repeat number BSSL genotype (HH) correlated with high CD4 cell numbers prior to infection (p = 0.007). In HIV-1 patients, delayed disease progression was linked to the HH BSSL genotype (RH = 0.462 CI = 0.282-0.757, p = 0.002) as was delayed emergence of X4 variants (RH = 0.525, 95% CI = 0.290-0.953, p = 0.034). The LH BSSL genotype, previously found to be associated with enhanced DC-SIGN binding of human milk, was identified to correlate with accelerated disease progression in our cohort of HIV-1 infected MSM (RH = 0.517, 95% CI = 0.328-0.818, p = 0.005). Conclusion: We identify BSSL as a marker for HIV-1 disease progression and emergence of X4 variants. Additionally, we identified a relation between BSSL genotype and CD4 cell counts prior to infectio

Syncope and Early Repolarization: A Benign or Dangerous ECG Finding?

Early repolarization is a well-described, common electrocardiographic variant. It was initially felt to be benign, but in the last twenty years a suggested a link between specific types of early repolarization and sudden cardiac death has emerged. This association was has been termed the J wave syndrome and includes both the high risk early repolarization and Brugada ECG patterns. The odds of early repolarization change being associated with poor outcomes are still exceedingly small. Nevertheless, the association of a fairly ubiquitous ECG finding with fatal or near fatal clinical outcomes has raised concern. How can we identify the truly high-risk patients? If a patient has a significant clinical event with a concerning ECG repolarization pattern, what should be done next? The authors of this review present current information regarding the Early Repolarization and Brugada Syndromes and how to proceed with diagnosis, management, and risk stratification when early repolarization change is observed on ECG