Use of the MicroSiM (µSiM) Barrier Tissue Platform for Modeling the Blood-Brain Barrier

The microSiM (µSiM) is a membrane-based culture platform for modeling the blood-brain barrier (BBB). Unlike conventional membrane-based platforms, the µSiM provides experimentalists with new capabilities, including live cell imaging, unhindered paracrine signaling between 'blood' and 'brain' chambers, and the ability to directly image immunofluorescence without the need for the extraction/remounting of membranes. Here we demonstrate the basic use of the platform to establish monoculture (endothelial cells) and co-culture (endothelial cells and pericytes) models of the BBB using ultrathin nanoporous silicon-nitride membranes. We demonstrate compatibility with both primary cell cultures and human induced pluripotent stem cell (hiPSC) cultures. We provide methods for qualitative analysis of BBB models via immunofluorescence staining and demonstrate the use of the µSiM for the quantitative assessment of barrier function in a small molecule permeability assay. The methods provided should enable users to establish their barrier models on the platform, advancing the use of tissue chip technology for studying human tissues.

Regnase-1 overexpression as a novel gene therapy approach for pulmonary hypertension

Introduction

Pulmonary hypertension (PH) is a chronic disease characterized by persistently increases pulmonary arterial pressure, leading on the long term to right ventricular overload and ultimately right heart failure. Until now, therapy focuses on alleviating symptoms and hence the development of a novel strategy for the treatment of this disease remains highly relevant.

Purpose

The importance of pro-inflammatory cytokines in progression of PH has already been established. Interestingly, patients with increased plasma levels of inflammatory markers present with more severe disease. Regnase-1 is a newly identified endoribonuclease cleaving the mRNA of pro-inflammatory cytokines therefore diminishing their levels of expression. Hence, we hypothesize that regnase-1 overexpression in lung tissue can be translated into a novel therapeutic approach for PH.

Methods

In vitro experiments were performed in human lung endothelial cells (HUVECs). For our in vivo study, mice were subjected to hypoxic conditions (10% O2) for 3 weeks. Regnase-1 overexpression was achieved in lung endothelial cells by transduction with targeted adeno-associated virus serotype 2 (AAV2-ESGHGYF), administered systemically by tail vein injection 3 days after exposure to hypoxia (early therapy approach). AAV2-EGFP treated mice served as controls. Right ventricular function was monitored by echocardiography and right ventricular systolic pressure was measured by right heart catheterization. The degree of pro-inflammatory cell infiltration was monitored by immunohistochemistry. Induction of fetal gene programme in the right ventricle was measured by real time qPCR. Fibrosis deposition in lung tissue was determined by Sirius Red staining of frozen sections.

Results

Regnase-1 overexpression led to a significantly decreased level of hypoxia-induced pro-inflammatory cytokines in HUVECs. Importantly, we could show decreased regnase-1 levels in lung endothelial cells of mice subjected to hypoxia for 3 weeks. On the other hand, regnase-1 reintroduction led to a significant improvement in right ventricular function and decreased pulmonary pressure in mice placed under hypoxic conditions. Moreover, the described gene therapy approach induced normalization of fetal gene programme in the cardiac tissue and reduced pro-inflammatory cell infiltration in lungs. Additionally, we could determine mitigation of pulmonary extracellular matrix deposition and fibrosis development in mice receiving AAV2-regnase1 as compared to controls.

Conclusion

AAV-mediated regnase-1 overexpression in lung endothelial cells results in amelioration of pathological events leading to PH in mice subjected to hypoxia, when the therapeutic AAV is delivered 3 days after disease induction. Further experiments will determine whether this method can be successful used for reversing already established PH.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DZHK

The Modular µSiM: A Mass Produced, Rapidly Assembled, and Reconfigurable Platform for the Study of Barrier Tissue Models In Vitro

Advanced in vitro tissue chip models can reduce and replace animal experimentation and may eventually support "on-chip" clinical trials. To realize this potential, however, tissue chip platforms must be both mass-produced and reconfigurable to allow for customized design. To address these unmet needs, an extension of the µSiM (microdevice featuring a silicon-nitride membrane) platform is introduced. The modular µSiM (m-µSiM) uses mass-produced components to enable rapid assembly and reconfiguration by laboratories without knowledge of microfabrication. The utility of the m-µSiM is demonstrated by establishing an hiPSC-derived blood-brain barrier (BBB) in bioengineering and nonengineering, brain barriers focused laboratories. In situ and sampling-based assays of small molecule diffusion are developed and validated as a measure of barrier function. BBB properties show excellent interlaboratory agreement and match expectations from literature, validating the m-µSiM as a platform for barrier models and demonstrating successful dissemination of components and protocols. The ability to quickly reconfigure the m-µSiM for coculture and immune cell transmigration studies through addition of accessories and/or quick exchange of components is then demonstrated. Because the development of modified components and accessories is easily achieved, custom designs of the m-µSiM shall be accessible to any laboratory desiring a barrier-style tissue chip platform.

Differentiation of human pluripotent stem cells to brain microvascular endothelial cell-like cells suitable to study immune cell interactions

We describe the extended endothelial cell culture method (EECM) for the differentiation of human pluripotent stem cells (hPSCs) into brain microvascular endothelial cell (BMEC)-like cells. EECM-BMEC-like cells resemble primary human BMECs in morphology, molecular junctional architecture, and diffusion barrier characteristics. A mature immune phenotype with proper endothelial adhesion molecule expression makes this model distinct from any other hPSC-derived in vitro blood-brain barrier (BBB) model and suitable to study immune cell migration across the BBB in a disease relevant and personalized fashion. For complete details on the use and execution of this protocol, please refer to Lian et al. (2014), Nishihara et al. (2020a).

The Radiological Evaluation of Posterior Superior Alveolar Artery by Using CBCT

BACKGROUND

Evaluation of the maxillary sinus anatomy prior to sinus lift procedures is important to avoid surgical complications due to the close anatomical relationship between the posterior maxillary region and the maxillary sinüs.

INTRODUCTION

In order to avoid traumatizing the posterior superior alveolar artery and to prevent perioperative bleeding, locating the exact position of the artery is imperative before the surgical procedures.

METHODS

150 CBCT scans were evaluated. The distance from the inferior border of the PSAA to the alveolar crest (the vertical line from the artery to the crest) and floor of the maxillary sinus, the distance from PSAA to medial sinus wall, nasal septum, zygomatic arch, position, the distance from the floor of maxillary sinüs to the alveolar crest and diameter of the PSAA were assessed. Locations of the artery were classified.

RESULTS

The artery diameters were mostly ≥ 1 mm. The artery was mostly intraosseous (59.7%), 21.7% was superficial and only 18.7% was intra-sinuscular.

CONCLUSION

The location of PSAA is intraosseous in most patients. The artery diameters were mostly ≥ 1 mm and we can say that increasing the size also increases the risk of complications.

Investigation the anterior mandibular lingual concavity by using cone-beam computed tomography

BACKGROUND

In the presence of lingual concavity in the mandible, the cortical perforation and consequently the life-threatening intraoral haemorrhages obstructing the upper respiratory tract may be seen during the surgical intervention. The present study was aimed to determine the prevalence of lingual concavity in the interforaminal region and its relationship with gender and dentate status.

MATERIALS AND METHODS

The images of 106 patients who underwent cone-beam computed tomography (CBCT) between 2016 and 2017 in Department of Dental and Maxillofacial Radiology Department of Faculty of Dentistry of Ondokuz Mayıs University were retrospectively examined. The images were obtained using a Galileos device (98 kVp, 15-30 mA). The bone height and width in interforaminal region and the frequency of lingual concavity were analysed.

RESULTS

Of patients involved in the present study, 42.5% were male and 57.5% were female After the examinations performed, the bone was morphologically classified into four classes as type I lingual concavity, type II inclined to lingual, type III enlarging towards labiolingual and type IV buccal concavity. Type III (77.9%) was the most common type in the anterior region, followed by type II (16.5%), type I (4.7%) and type IV (0.9%). The lingual concavity angle was 76.5 ± 3.69º and the concavity depth was 2.09 ± 0.34 mm.

CONCLUSIONS

The lingual concavity can be detected by using the cross-sectional CBCT images and the complications related with lingual cortical perforation can be prevented.

A retrospective evaluation of traumatic dental injury in children who applied to the dental hospital, Turkey

OBJECTIVE

The purpose of this study was to analyze traumatic dental injuries in children visiting the dental hospital emergency department in Samsun of Turkey, in the period from 2007 to 2011.

MATERIALS AND METHODS

Data of age, gender, causes of dental trauma, injured teeth, type of dental injuries, the application period, the dental treatments, and traumatic dental injuries according to the seasons were obtained from the records at dental hospital.

RESULTS

Of all 320 patients with traumatic dental injury, 205 were boys and 115 were girls with a boys/girls ratio 1.78:1. Traumatic dental injury was observed more frequently in the 7-12 age groups: 52.5% in girls and 67.8% in boys. Falls are the major cause of traumatic dental injury in the age group 6-12 (51.4%). Sport activities are a common cause of traumatic dental injury in the 7-12 age group (34.2%). Patients visited a dentist within approximately 2 h (57.1%). The upper anterior teeth were subjected to trauma more frequently than the lower anterior teeth. The maxillary central incisors were the most commonly affected teeth, and the mandibular canins were the least affected teeth. In primary teeth, avulsion was the most common type of dental injury (23%); on the other hand, enamel fractures were the most common type of dental injury (30.6%) observed in permanent teeth. In the primary dentition, the most commonly performed treatments were dental examination and prescribing (70%). The most common treatment choices in permanent teeth were restoration and dental examination (49.7 and 15.8%, respectively).

CONCLUSION

The results of the study show that the emergency intervention to traumatized teeth is important for good prognosis of teeth and oral tissues. Therefore, the parents should be informed about dental trauma in schools, and dental hospital physicians should be subjected to postgraduate training.