Mark Praetorius

Transsynaptic delivery of nanoparticles to the central auditory nervous system

Conclusion. Silica nanoparticles may serve as a nonviral delivery system to the sensory hair cells, spiral ganglion cells within the cochlea, and the vestibular organ, as well as the cochlear nucleus. Objectives. At present there are no targeted therapeutics for inner ear disease. A variety of viral vector systems have been tested in the inner ear with variable efficacy but they are still not regarded as safe systems for inner ear delivery. Nanoparticles are a nonviral method of delivering a variety of macromolecules that potentially can be used for delivery within the auditory system. In this study, we evaluated the distribution and safety of nanoparticles in the inner ear. Materials and methods. Cy3-labeled silica nanoparticles were placed on the round window membrane of adult mice. Hearing thresholds were determined after nanoparticle delivery by auditory brainstem responses (ABRs). Distribution of particles was determined by histological evaluation of the cochlea, vestibular organs, and brain stem. Results. Fluorescent microscopy demonstrated Cy3-labeled nanoparticles signals in the sensory hair cells and the spiral ganglion neurons of both the treated and contralateral inner ears. Additionally, the distal part of the central auditory pathway (dorsal cochlear nucleus, superior olivary complex) was found to be labeled with the Cy3-linked silica nanoparticles, indicating a retrograde axonal transport. No hearing loss or inflammation was noted in the treated cochlea.

General and disease-specific quality of life in patients with chronic suppurative otitis media - a prospective study

BackgroundChronic suppurative otitis media (CSOM) is frequently associated with symptoms of inflammation like discharge from the ear or pain. In many cases, patients suffer from hearing loss causing communication problems and social withdrawal. The objective of this work was to collect prospective audiological data and data on general and disease-specific quality of life with validated quality of life measurement instruments to assess the impact of the disease on health-related quality of life (HR-QOL).Methods121 patients were included in the study. Patients were clinically examined in the hospital before and 6 months after surgery including audiological testing. They filled in the quality of life questionnaires SF-36 and Chronic Otitis Media Outcome Test 15 (COMOT-15) pre-operatively and 6 and 12 months post-operatively, respectively.ResultsComplete data records from 90 patients were available for statistical analysis. Disease-specific HR-QOL in patients with CSOM improved after tympanoplasty in all the scales of the COMOT-15. There was no difference in HR-QOL assessment between patients with mesotympanic respectively epitympanic CSOM. However, we did find the outcome to be worse in patients who received revision surgery compared with those receiving primary surgery. Audiometric findings correlated very well with the subscale hearing function from the COMOT-15 questionnaire. General HR-QOL measured with the SF-36 was not significantly changed by tympanoplasty.ConclusionsTympanoplasty did lead to a significant improvement of disease-specific HR-QOL in patients with CSOM while general HR-QOL did not change. Very well correlations were found between the subscale hearing function from the COMOT-15 questionnaire and audiological findings. Revision surgery seems to be a predictor for a worse outcome.

Bcl-2 Gene Therapy Prevents Aminoglycoside-Induced Degeneration of Auditory and Vestibular Hair Cells

To evaluate the protective effects of bcl-2, we have developed an in vivo model of gentamicin ototoxicity in C57BL/6 mice using intratympanic delivery of gentamicin. Hair cell survival was evaluated using myosin VIIa immunohistochemistry, cytocochleogram and auditory brainstem response (ABR) testing. At 10 days after gentamicin application, a consistent loss of outer hair cells was seen. Mice were pretreated with an adenovector expressing human bcl-2 (Ad.11D.bcl-2) or a control vector (Ad.11D). Seventy-two hours after vector delivery mice were treated with intratympanic gentamicin and evaluated at 10 days after ototoxin delivery. Pretreatment with Ad.11D.bcl-2 resulted in morphologic protection of hair cells and preservation of hearing thresholds measured by ABR.

Otorhinolaryngologic disorders and diving accidents: an analysis of 306 divers.

Diving is a very popular leasure activity with an increasing number of participants. As more than 80% of the diving related problems involve the head and neck region, every otorhinolaryngologist should be familiar with diving medical standards. We here present an analysis of more than 300 patients we have treated in the past four years. Between January 2002 and October 2005, 306 patients presented in our department with otorhinological disorders after diving, or after diving accidents. We collected the following data: name, sex, age, date of treatment, date of accident, diagnosis, special aspects of the diagnosis, number of dives, diving certification, whether and which surgery had been performed, history of acute diving accidents or follow up treatment, assessment of fitness to dive and special remarks. The study setting was a retrospective cohort study. The distribution of the disorders was as follows: 24 divers (8%) with external ear disorders, 140 divers (46%) with middle ear disorders, 56 divers (18%) with inner ear disorders, 53 divers (17%) with disorders of the nose and sinuses, 24 divers (8%) with decompression illness (DCI) and 9 divers (3%) who complained of various symptoms. Only 18% of the divers presented with acute disorders. The most common disorder (24%) was Eustachian tube dysfunction. Female divers were significantly more often affected. Chronic sinusitis was found to be associated with a significantly higher number of performed dives. Conservative treatment failed in 30% of the patients but sinus surgery relieved symptoms in all patients of this group. The middle ear is the main problem area for divers. Middle ear ventilation problems due to Eustachian tube dysfunction can be treated conservatively with excellent results whereas pathology of the tympanic membrane and ossicular chain often require surgery. More than four out of five patients visited our department to re-establish their fitness to dive. Although the treatment of acute diving-related disorders is an important field for the treatment of divers, the main need of divers seems to be assessment and recovery of their fitness to dive.

Development of gene therapy for inner ear disease: Using bilateral vestibular hypofunction as a vehicle for translational research

Despite the significant impact of hearing and balance disorders on the general population there are currently no dedicated pharmaceuticals that target the inner ear. Advances in molecular biology and neuroscience have improved our understanding of the inner ear allowing the development of a range of molecular targets that have the potential to treat both hearing and balance disorders. One of the principal advantages of the inner ear is that it is accessible through a variety of approaches that would allow a potential to be delivered locally rather than systemically. This significantly broadens the potential medications that can be developed and opens the possibility of local gene delivery as a therapeutic intervention. Several potential clinical targets have been identified including delivery of neurotrophin expressing genes as an adjunct to cochlear implantation, delivery of protective genes to prevent trauma and the development of strategies for regenerating inner ear sensory cells. In order to translate these potential therapeutics into humans we will want to optimize the gene delivery methodology, dosing and activity of the drug for therapeutic value. To this end we have developed a series of adenovectors that efficiently transduce the inner ear. The use of these gene delivery approaches are attractive for the potential of hair cell regeneration after loss induced by trauma or ototoxins. This approach is particularly suited for the development of molecular therapies targeted at the vestibular system given that no device based therapeutic such a cochlear implant available for vestibular loss.

Adenovector-mediated hair cell regeneration is affected by promoter type

Abstract Conclusion: Replacement of vestibular hair cells induced by atoh1 driven by the tissue-specific GFAP promoter was significantly more efficient than use of the cBA or hCMV promoter. Objective: To test whether expression level, persistence, or selectivity from adenovirus vectors delivered in the inner ear can be altered by changing the adenovector backbone or by using different cellular and viral promoters. Materials and methods: Adenovector and promoter modifications were tested for differences in transgene expression in adult macular organs. The effect of using an E1/E3 deleted vector was compared to E1/E3/E4 deleted vectors. The effect of using viral and cellular promoters to modify transgene expression was tested in explanted adult mouse macular organs. Based on these results three different promoters were tested for efficacy of atonal gene. Results: Use of adenovectors containing human CMV, the hybrid cBA and ubiquitin promoters driving transgene expression resulted in different types of transgene expression. While several viral and cellular promoters provided broad cell type expression, expression driven by the GFAP promoter was limited to vestibular supporting cells, demonstrating the specificity of this promoter.

Adenoviral vectors for improved gene delivery to the inner ear

An important requirement for gene therapy in the inner ear is to achieve efficient gene delivery without damaging residual inner ear function. This can be achieved by delivering a high concentration of vector in a minimal volume. Adenovectors are well suited to meet these requirements since high quality concentrated vector with a high capacity for a gene payload can be produced. To reduce the number of vector particles and volume of delivery to the inner ear, we tested vectors with enhancements in cell binding and cell entry properties. We compared delivery of a marker gene to the inner ear using two different advanced generation serotype 5 adenovector designs. The first adenovector tested, AdRGD, has a restricted tropism of entry into cells. AdRGD is an Ad5 capsid vector with an arg-gly-asp (RGD) motif built into the adenovector fiber that has also been modified to abolish the fiber-CAR and penton-integrin interactions that provide the normal well characterized two-step entry pathway for adenovirus. The AdRGD vector has enhanced binding to alphanu integrins. The second vector, AdF2K, contains 7 lysine residues within the fiber knob and has been shown to have expanded tropism for cells in vitro and in vivo. AdF2K maintains its normal CAR and integrin receptors interactions and has an additional mechanism of entry via its ability to interact with heparan sulfate. Both vectors demonstrated effective delivery to the inner ear and more uniform labeling of the inner ear sensory epithelia than native capsid vector, when tested in vivo. Analysis of expression efficiency using quantitative PCR was tested in vitro on cultured macular organs and demonstrated that vector delivery with the AdF2K vector design yielded optimal delivery. The present study demonstrates that retargeting strategies can improve delivery to the inner ear.

Pharmacodynamics of adenovector distribution within the inner ear tissues of the mouse.

Recent studies have demonstrated that delivery of genes to the inner ear can achieve a variety of effects ranging from support of auditory neuron survival to protection and restoration of hair cells, demonstrating the utility of vector based gene delivery. Translation of these findings to useful experimental systems or even clinical applications requires a detailed understanding of the pharmacokinetics of gene delivery in the inner ear. Ideal gene delivery systems will employ a well tolerated vector which efficiently transduces the appropriate target cells within a tissue, but spare non-target structures. Adenovectors based on serotype 5 (Ad 5) are commonly used vectors, are easy to construct and have a long track record of efficacious gene transfer in the inner ear. In this study we demonstrate that distribution of Ad5 vector occurs in a basal to apical gradient with rapid distribution of vector to the vestibule after delivery via a round window cochleostomy. Transduction of the vector and expression of the delivered transgene occurs by 10 min post vector delivery. At 24 h post delivery only 16% of vector that was initially detectable within the inner ear by quantitative PCR remained. Perilymph sampling was used to determine that vector concentrations in perilymph peaked at 30 min post delivery and then declined rapidly. Understanding these basic distribution patterns and parameters for delivery are important for the design of gene delivery vectors and vital for modeling dose responses to achieve safe efficacious delivery of a therapeutic agent.

[Patients with chronic rhinosinusitis: disease-specific and general health-related quality of life].

ZusammenfassungHintergrundDer ausgeprägt negative Effekt der chronischen Rhinosinusitis auf die gesundheitsbezogene Lebensqualität der Patienten wird häufig unterschätzt. Bisher existieren nur wenige Studien, die an deutschsprachigen Patientenkollektiven die gesundheitsbezogene Lebensqualität mit validierten Messinstrumenten erheben.Patienten und MethodenPräoperativ wurden 163xa0Patienten in die Studie einbezogen. Davon nahmen nach 3xa0Monaten 123xa0Patienten und nach einem Jahr 82xa0Patienten an der Befragung teil. Als Lebensqualitätsmessinstrumente wurden der Sino-Nasal Outcome Test 20 German Adapted Version und der Short Form 36 Health Survey (SF-36) eingesetzt. Die Daten des deutschen Normkollektives des SF-36 wurden für die Auswertung herangezogen.ErgebnissePostoperativ konnte in allen Skalen beider Messinstrumente eine signifikante Verbesserung der gesundheitsbezogenen Lebensqualität festgestellt werden. Im Vergleich mit dem deutschen Normkollektiv konnte in 7 von 8 Skalen des SF-36 eine dauerhafte Angleichung an das durchschnittliche Bewertungsniveau erreicht werden.SchlussfolgerungenDie funktionelle endonasale Nasennebenhöhlenchirurgie bei Patienten mit chronischer Rhinosinusitis führt zu einer umfassenden signifikanten Verbesserung der krankheitsspezifischen und allgemeinen gesundheitsbezogenen Lebensqualität.AbstractBackgroundThe negative effect of chronic rhinosinusitis on patient quality of life has been generally underappreciated and undervalued. So far, only a few studies have examined health-related quality of life at German language patient collectives with validated measuring instruments.Patients and methodsPreoperatively, 163xa0patients were included into the study. Three months and 1xa0year after functional endonasal sinus surgery 123 and 82 patients, respectively, participated in the questioning. To measure health-related quality of life, we used version 20 of the German Adapted Version of the Sinonasal Outcome Test and the Short Form 36 Health Survey (SF-36). The German normative values of the SF-36 were used for analysis.ResultsPostoperatively, a significant improvement in health-related quality of life was determined on all scales of both measuring instruments. Comparing our data with the German normative values of the SF-36, we found a lasting approximation of the average assessment levels in seven of eight scales.ConclusionFunctional endonasal sinus surgery leads to significant improvements in disease-specific and general quality of life in patients with chronic rhinosinusitis.

Patienten mit chronischer Rhinosinusitis

ZusammenfassungHintergrundDer ausgeprägt negative Effekt der chronischen Rhinosinusitis auf die gesundheitsbezogene Lebensqualität der Patienten wird häufig unterschätzt. Bisher existieren nur wenige Studien, die an deutschsprachigen Patientenkollektiven die gesundheitsbezogene Lebensqualität mit validierten Messinstrumenten erheben.Patienten und MethodenPräoperativ wurden 163xa0Patienten in die Studie einbezogen. Davon nahmen nach 3xa0Monaten 123xa0Patienten und nach einem Jahr 82xa0Patienten an der Befragung teil. Als Lebensqualitätsmessinstrumente wurden der Sino-Nasal Outcome Test 20 German Adapted Version und der Short Form 36 Health Survey (SF-36) eingesetzt. Die Daten des deutschen Normkollektives des SF-36 wurden für die Auswertung herangezogen.ErgebnissePostoperativ konnte in allen Skalen beider Messinstrumente eine signifikante Verbesserung der gesundheitsbezogenen Lebensqualität festgestellt werden. Im Vergleich mit dem deutschen Normkollektiv konnte in 7 von 8 Skalen des SF-36 eine dauerhafte Angleichung an das durchschnittliche Bewertungsniveau erreicht werden.SchlussfolgerungenDie funktionelle endonasale Nasennebenhöhlenchirurgie bei Patienten mit chronischer Rhinosinusitis führt zu einer umfassenden signifikanten Verbesserung der krankheitsspezifischen und allgemeinen gesundheitsbezogenen Lebensqualität.AbstractBackgroundThe negative effect of chronic rhinosinusitis on patient quality of life has been generally underappreciated and undervalued. So far, only a few studies have examined health-related quality of life at German language patient collectives with validated measuring instruments.Patients and methodsPreoperatively, 163xa0patients were included into the study. Three months and 1xa0year after functional endonasal sinus surgery 123 and 82 patients, respectively, participated in the questioning. To measure health-related quality of life, we used version 20 of the German Adapted Version of the Sinonasal Outcome Test and the Short Form 36 Health Survey (SF-36). The German normative values of the SF-36 were used for analysis.ResultsPostoperatively, a significant improvement in health-related quality of life was determined on all scales of both measuring instruments. Comparing our data with the German normative values of the SF-36, we found a lasting approximation of the average assessment levels in seven of eight scales.ConclusionFunctional endonasal sinus surgery leads to significant improvements in disease-specific and general quality of life in patients with chronic rhinosinusitis.