Vascularized Tissue Research Articles

An Arteriovenous Bioreactor Perfusion System for Physiological In Vitro Culture of Complex Vascularized Tissue Constructs

Background: The generation and perfusion of complex vascularized tissues in vitro requires sophisticated perfusion techniques. For multiscale arteriovenous networks, not only the arterial, but also the venous, biomechanical and biochemical conditions that physiologically exist in the human body must be accurately emulated. For this, we here present a modular arteriovenous perfusion system for the in vitro culture of a multi-scale bioartificial vascular network. Methods: The custom-built perfusion system consisted of two circuits: in the arterial circuit, physiological arterial biomechanical and biochemical conditions were simulated using a modular set-up with a pulsatile peristaltic pump, compliance chambers, and resistors. In the venous circuit, venous conditions were emulated accordingly. In the center of the system, a bioartificial multi-scale vascularized fibrin-based tissue was perfused by both circuits simultaneously under biomimetic arteriovenous conditions. Culture conditions were monitored continuously using a multi-sensor monitoring system. Results: The physiological arterial and venous pressure- and flow-curves, as well as the microvascular arteriovenous oxygen partial pressure gradient, were accurately emulated in the perfusion system. The multi-sensor monitoring system facilitated live monitoring of the respective parameters and data-logging. In a proof-of-concept experiment, vascularized three-dimensional fibrin tissues showed sustained cell viability and homogenous microvessel formation after culture in the perfusion system. Conclusions: The arteriovenous perfusion system facilitated the in vitro culture of a multiscale vascularized tissue under physiological pressure-, flow-, and oxygen-gradient conditions. With that, it presents a promising technique for the in vitro generation and culture of complex large-scale vascularized tissues.

Abstract 4124354: Transplantation of vascularized cardiac microtissue derived from human iPS cells improves impaired electrical conduction capacity in a porcine myocardial injury model

Background: To realize efficient regenerative medicine using human iPS cell (hiPSC)-derived cardiac tissue, it is necessary to achieve electrical synchronization between the graft and the host heart and to improve conduction disturbances in the impaired heart. In this study, we aimed to demonstrate that the transplantation of hiPSC-derived vascularized cardiac tissue can improve these conduction disturbances using a porcine myocardial injury model. Methods: We prepared cell sheet-shaped vascularized cardiac microtissue (VCM) by seeding cardiomyocytes, endothelial cells, and vascular mural cells differentiated from hiPSCs onto temperature-responsive culture plates and thickening them using dynamic rocking culture. We induced myocardial injury (MI) via epicardial cryoablation in immunosuppressed crown minipigs and transplanted the VCMs immediately after MI induction, covering the cryoinjury-induced MI area. The pigs underwent epicardial electroanatomic mapping under sinus rhythm and epicardial pacing, both immediately before and one week after MI induction, while using amiodarone. Differences in myocardial voltages and conduction velocities were assessed between VCM and sham groups (N=3 in each group). After electroanatomic analysis, the hearts were harvested and subjected to histological examination. Results: One week after MI induction, mean voltages at the MI site decreased in both groups during sinus rhythm, remote site pacing, and combined remote and MI site pacing (11.05 to 1.74 mV, 14.26 to 3.44 mV, and 15.61 to 3.67 mV, respectively, in the VCM group; and 8.72 to 2.70 mV, 19.64 to 3.64 mV, and 14.66 to 1.96 mV, respectively, in the Sham group). Mean voltages at the remote site also decreased in both groups during the same conditions (12.57 to 4.53 mV, 10.61 to 3.38 mV, and 19.56 to 5.85 mV, respectively, in the VCM group; and 8.75 to 6.03 mV, 14.15 to 5.79 mV, and 13.67 to 6.23 mV, respectively, in the Sham group). The mean conduction velocity between the remote and MI sites was numerically higher in the VCM group compared to the Sham group (2.84 m/s vs. 1.74 m/s, respectively). Histological examination confirmed that in the VCM transplantation group, the VCM remained intact, completely covering the MI area. Conclusions: The transplantation of VCM showed a tendency to improve conduction disturbances in the porcine MI model. This suggests that the graft may synchronize with the host and function mechanically after cell transplantation.

Comparing DCE-MRI and DSA: Understanding the embolization of hypervascular spinal metastases.

This study aims to examine and compare the effectiveness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and Digital Subtraction Angiography (DSA) in evaluating hypervascular spinal metastases. A comprehensive literature review was conducted, utilizing top-tier databases such as PubMed, Scopus and Google Scholar, to compile an authoritative and up-to-date overview of the current advancements in the field. We synthesized key studies focusing on the advantages, limitations and efficacy of both imaging techniques. DCE-MRI provides a non-invasive method for evaluating tissue morphology, perfusion and vascularity, offering valuable information for cancer diagnosis and treatment monitoring. In contrast, DSA is an invasive procedure primarily used for embolization and diagnosing cerebrovascular events. Both modalities have distinct features regarding image acquisition, contrast agents, resolution and accessibility. DCE-MRI shows promise for cancer-related applications, offering advantages over conventional MRI by incorporating anatomical and hemodynamic parameters. While DSA remains important for cases requiring critical vascular information, further research is necessary to explore its potential therapeutic benefits in assessing vessel patency. Continued investigations are crucial to uncover additional insights and therapeutic applications for both DCE-MRI and DSA in medical imaging.

ADVANCES IN ORTHOPEDIC SURGERY

Orthopaedic surgery has undergone significant evolution with the development of minimally invasive techniques (MIT) for the treatment of complex lower limb fractures. These innovations have transformed orthopaedic management, offering less traumatic and more effective alternatives to traditional procedures. IMTs are designed to reduce tissue damage, speed up recovery and minimize post-operative complications, making them increasingly relevant in today’s orthopaedic scenario. The aim of this study is to discuss recent advances in minimally invasive techniques in orthopaedic surgery for complex lower limb fractures. The research explores the benefits of these techniques, the challenges faced in clinical practice and the future prospects for their widespread adoption. The research was based on a literature review, with a qualitative approach, using the PubMed, Google Scholar, and Scielo databases. For a comprehensive and relevant analysis of the advances and challenges of minimally invasive techniques in orthopaedic surgery, specific descriptors reflecting the area of study were applied, with a time frame covering publications from 2018 to 2023. The analysis is based on a review of up-to-date literature, including clinical studies and meta-analyses that demonstrate the efficacy and safety of minimally invasive techniques. Innovations such as the use of external fixators, locked intramedullary rods and surgical navigation systems are highlighted. These approaches allow for precise stabilization of fractures with smaller incisions and less impairment of soft tissue vascularization. In addition, advances in intraoperative imaging and surgical instrumentation are discussed, which have improved the precision of procedures and reduced operative time. Challenges such as the learning curve and the cost of the technologies are also addressed. Thus, advances in minimally invasive techniques have revolutionized orthopaedic surgery, offering effective solutions for the treatment of complex lower limb fractures. Despite the challenges, such as the need for specialized training and investment in new technologies, the benefits for patients, including shorter recovery times and better functional results, are undeniable. The future of orthopaedic surgery will continue to benefit from these innovations, with the potential to further increase access and the quality of treatments.

Conjunctival squamous metaplasia on amniotic membrane in Stevens-Johnson syndrome: a case report

BackgroundTo present a case of conjunctival growth on the amniotic membrane and subsequent pathology revealing conjunctival squamous metaplasia in a patient with Stevens-Johnson syndrome.Case presentationA 21-year-old female presented with painful, blurred vision in both eyes for two weeks. She was diagnosed with Stevens-Johnson syndrome 5 weeks before. Due to bilateral corneal epithelial defects, ProKera®, an amniotic membrane corneal bandage with a polycarbonate ring, was placed in both eyes. However, three weeks later, a slit-lamp examination revealed vascularized tissue growth from the palpebral conjunctiva to the amniotic membrane, along with symblepharon formation in the left eye. The patient underwent conjunctival biopsy, amniotic membrane removal, and symblepharon release. Pathology report showed the growth of squamous epithelium on the acellular amniotic membrane. Immunohistochemistry further supported the diagnosis, revealing squamous markers through p40 staining and highlighting the presence of the amniotic membrane using trichrome stain. Three months later, the patient’s visual acuity had improved to 20/25 and no symblepharon was noted.ConclusionsThis is the first case of conjunctival squamous metaplasia on amniotic membrane associated with Stevens-Johnson syndrome. Our case indicates that, despite the anti-inflammatory properties of amniotic membrane, conjunctival squamous metaplasia may arise after amniotic membrane grafting due to intense inflammation in Stevens-Johnson syndrome. Clinicians should conduct regular monitoring before amniotic membrane dissolution to preclude the development of conjunctival squamous metaplasia on the membrane and potential invasion into the cornea.

Ultrasound and magnetic resonance imaging (MRI) features of angioleiomyoma.

Vascular leiomyoma or angioleiomyoma is a rare benign tumor which belongs to the group of benign smooth muscle tumors. They are commonly located at the extremities, usually presented as a painful solitary lesion in the subcutaneous tissue. To date, very few reports describe its characteristics from an imaging point of view, especially their ultrasound characteristics, making it difficult to do a pre-surgical diagnosis. Our purpose is to describe the clinical, pathologic and imaging features of angioleiomyoma [ultrasound, Doppler ultrasound and magnetic resonance imaging (MRI) findings]. We retrospectively reviewed from the pathology database from Hospital Universitario Fundación Alcorcón, Madrid, Spain, the clinical histories of 139 patients who had surgical excision and histologic diagnosis of angioleiomyoma during the last 17 years, from May 31st 2006 to April 17th 2023. Of those patients, we focused on 50 who had soft tissue angioleiomyoma with imaging study [ultrasonography (US) and/or MRI] performed in our institution, making a descriptive cross-sectional study. In our series, a very characteristic ultrasonographic and US Doppler pattern was found. It consists in the presence of a well defined, homogeneous and highly vascularized soft tissue tumor, sometimes with the presence of a feeding vessel. When the described US features appear in a mobile and elastic subcutaneous slow growing tumor on an extremity, the diagnosis of angioleiomyoma should be considered as highly probable.

In Vitro Vascularization Improves In Vivo Functionality of Human Engineered Cardiac Tissues

Engineered human cardiac tissues hold great promise for disease modeling, drug development, and regenerative therapy. For regenerative applications, successful engineered tissue engraftment in vivo requires rapid vascularization and blood perfusion post-implantation. In the present study, we engineered highly functional, vascularized cardiac tissues (“cardiopatches”) by co-culturing human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and endothelial cells (hiPSC-ECs) in optimized serum-free media. The vascularized cardiopatches displayed stable capillary networks over 4 weeks of culture, the longest reported in the field, while maintaining high contractile stress (>15 mN/mm2) and fast conduction velocity (>20 cm/s). Robustness of the method was confirmed using two distinct hiPSC-EC sources. Upon implantation into dorsal-skinfold chambers in immunocompromised mice, in vitro vascularized cardiopatches exhibited improved angiogenesis compared to avascular implants. Significant lumenization of the engineered human vasculature and anastomosis with host mouse vessels yielded the formation of hybrid human-mouse capillaries and robust cardiopatch perfusion by blood. Moreover, compared to avascular tissues, the implanted vascularized cardiopatches exhibited significantly higher conduction velocity and Ca2+ transient amplitude, longitudinally monitored in live mice for the first time. Overall, we demonstrate successful 4-week vascularization of engineered human cardiac tissues without loss of function in vitro, which promotes tissue functionality upon implantation in vivo. Statement of SignificanceComplex interactions between cardiac muscle fibers and surrounding capillaries are critical for everyday function of the heart. Tissue engineering is a powerful method to recreate functional cardiac muscle and its vascular network, which are both lost during a heart attack. Our study demonstrates in vitro engineering of dense capillary networks within highly functional engineered heart tissues that successfully maintain the structure, electrical, and mechanical function long-term. In mice, human capillaries from these engineered tissues integrate with host mouse capillaries to allow blood perfusion and support improved implant function. In the future, the developed vascularized engineered heart tissues will be used for in vitro studies of cardiac development and disease and as a potential regenerative therapy for heart attack.

Modified salpingopharyngeus myomucosal flap: a novel technique for skull base reconstruction.

Advancements in endoscopic skull base surgery have enabled complex tumor resections, necessitating a variety of reliable reconstructive techniques to repair resultant defects. Vascularized flaps represent optimal options, but frequently used local pedicled intranasal flaps may be unavailable due to tumor invasion or prior surgery. This study applies a modification to the previously described salpingopharyngeus myomucosal flap (Dicle flap) with potential for its use in extensive endoscopic skull base surgery defect's repair. Cadaveric dissections (n = 5) were performed utilizing endoscopic visualization to access the skull base via endonasal and transoral routes. A superiorly based posterior pharyngeal myomucosal flap along the salpingopharyngeus muscle was elevated off the superior pharyngeal constrictors, preserving their vascular pedicles. This combined flap could be 180 degrees transposed to reconstruct clival defects up to the sella turcica. The modified salpingopharyngeus myomucosal flap (Modified Dicle flap) provided approximately 40 cm2 of robust vascularized tissue based on the ascending pharyngeal artery and random posterior pharyngeal vessels. It was sufficiently mobilized to cover extensive skull base defects in the craniocervical junction, sella turcica, and protecting the exposed internal carotid artery segments. The modified Dicle flap offers a viable reconstructive option for extensive endoscopic endonasal skull base defects when commonly utilized vascularized flaps are unavailable. Further research on clinical cases is warranted to investigate postoperative function and refine techniques to minimize donor site morbidity. Not applicable.

Bone Destruction-Chemotactic Osteoprogenitor Cells Deliver Liposome Nanomedicines for the Treatment of Osteosarcoma and Osteoporosis.

Therapeutic efficacy of skeletal diseases is usually limited by unfavorable drug delivery due to incapable bone targeting and low bone affinity of conventional drug carriers, as well as relatively reduced vascularization and dense structure of bone tissues. Due to CXC chemokine receptor 4 (CXCR4)/CXC chemokine ligand 12 (CXCL12) signal axis-guided recruitment, osteoprogenitor cells (OPCs) can actively migrate to bone disease nidus. Here, drugs-loaded nanoliposomes are prepared and decorated onto OPCs by biotin-streptavidin linkage for precise bone disease targeting and effective drug delivery. In mouse models of tibia defect and orthotopic osteosarcoma, superior targeting property of OPCs-based drug delivery systems toward diseased bone niduses is verified. By encapsulating antitumor and antiosteoporosis drugs into nanoliposomes, OPCs-based drug delivery systems effectively inhibit disease development and restore bone destruction in mouse models of orthotopic osteosarcoma and ovariectomized osteoporosis. This study reveals a cell-based drug delivery system for precise bone disease targeting and highly effective drug delivery, which will find great potential as a universal drug delivery platform for targeting treatment of various bone diseases.

Advances of natural hydrogel-based vascularization strategies for soft tissue repair

Regeneration of soft tissues, especially those requiring complex vascularization, is a major challenge in the field of tissue engineering. The current types of tissue engineering scaffolds include sponges, electric spinning silk, hydrogels, and 3D printed biomaterials. Among them, hydrogels have the unique property of mimicking extracellular matrix (ECM), which can provide a relatively stable microenvironment for cellular activities and facilitate cell adhesion, proliferation, and differentiation; thus, have become a promising scaffold. In this paper, we present a review of the commonly used types of natural hydrogels and their applications as scaffolds in tissue vascularization. First, we enumerate the importance and advantages of several types of commonly used hydrogels of natural origin in terms of fabricating vascularized tissues or organs. Second, we discuss two different formation modalities of blood vessels, as well as natural hydrogel-based vascularization strategies, including carrying growth factors, stem cell delivery, special scaffold structures and pharmaceutical-enhanced strategy. In addition, we describe the crosslinking strategies of hydrogels as scaffolds for regeneration of vascularized soft tissues, as well as the factors affecting it. Finally, new insights are provided for the development of natural hydrogel-based vascularized soft tissue regeneration research.

Light and scanning electron microscope characterization of mandibular symphysis tissue as a functional adaptation in the mandible development of human fetuses.

When developing, the mandible presents great plasticity and contains condensed mesenchymal cells that develops into Meckel's cartilage, of which the anterior part forms the mandibular symphysis. Mandible human development studies focus on investigating whether the beginning of mandibular fusion in fetal period is related to symphysis ossification and the tensions imposed on it, considering that tongue movements, mouth opening, and closing can be seen in fetuses. This research analyses tissue modifications during human mandibular symphysis growth using light and scanning electron microscopy to relate them to its functional structure. The study sample consisted of 12 human fetuses distributed into two groups: Group I (GI) of 10-14 weeks old and Group II (GII) of 20-24 weeks old. Fragments of mandibular symphysis were removed en bloc together with the surrounding tissues to preserve the relation with adjacent structures. Decalcified specimens were prepared in semi-serial coronal sections 5-μm-thick and stained with hematoxylin and eosin, Masson՚s trichrome, Verhoeff, and Sirius red for histological analysis with light microscopy. Collagen fibers Type I or III and elastic fibers were quantified by volume fraction (Vv). Coronal sections of the GI and GII symphyseal region were submitted to scanning electron microscopy. Comparison between groups used independent t-test. Our study presents the different endochondral ossification stages in the anterior part of Meckel's cartilage in GI. Both groups showed abundantly vascularized mesenchymal tissue with intense cellular activity forming the mandibular symphysis, such as a source of new osteoblasts adjacent to the newly deposited bone matrix. Scanning electron microscopy analysis revealed an invasion of the bony trabecula in the transverse direction from the hemimandible, rectilinear in GI and sinuous in GII due to interdigitating bone process, promoting its ossification. In collagen Vv analysis was verified a prevalence of type I in GII and type III in GI, indicating a proportional relation between maturation and tissue arrangement. Functionally, the collagen and elastic fibers in the mandibular symphysis were arranged in a pantographic network, and the fibrillar interconnectivity clearly contributes to resilience capacity and efficiency of the force transfer. This study inferred the functional significance of the knowledge about the tissue composition of mandibular symphysis, and the importance of this tissue for surrounding structures. The mesenchymal tissue of mandibular symphysis participates in bone growth process, revealing an adaptation mechanism of mandibular symphysis in the fetal period investigated.

Hydrogel-Based Vascularized Organ Tissue Engineering: A Systematized Review on Abdominal Organs.

Biomedical engineering, especially tissue engineering, is trying to provide an alternative solution to generate functional organs/tissues for use in various applications. These include beyond the final goal of transplantation, disease modeling and drug discovery as well. The aim of this study is to comprehensively review the existing literature on hydrogel-based vascularized organ (i.e., liver, pancreas, kidneys, intestine, stomach and spleen) tissue engineering of the abdominal organs. A comprehensive literature search was conducted on the Scopus database (latest search 1 September 2024). The research studies including hydrogel-based vascularized organ tissue engineering in the organs examined here were eligible for the review. Herein, 18 studies were included. Specifically, 10 studies included the liver or hepatic tissue, 5 studies included the pancreas or pancreatic islet tissue, 3 studies included the kidney or renal tissue, 1 study included the intestine or intestinal or bowel tissue, 1 study included the stomach or gastric tissue, and 0 studies included spleen tissue. Hydrogels are biocompatible materials with ideal characteristics for use as scaffolds. Even though organ tissue engineering is a rapidly growing field, there are still many obstacles to overcome to create a fully functional and long-lasting organ.

ESOMA-DM1, a Maytansinoid-Based Theranostic Small-Molecule Drug Conjugate for Neuroendocrine Tumors.

Background: The main challenges of conventional chemotherapy lie in its lack of selectivity and specificity, leading to significant side effects. Using a small-molecule drug conjugate (SMDC) ensures specific delivery of a cytotoxic drug to the tumor site by coupling it to a targeting vector. This promising strategy can be applied to neuroendocrine tumors (NETs) by choosing a targeting vector that binds specifically to somatostatin receptor subtype 2 (SSTR2). Additionally, incorporation of a bifunctional chelate into the molecule enables complexation of both diagnostic and therapeutic radionuclides. Thus, it facilitates monitoring of the distribution of the SMDC in the body and allows for the implementation of combination therapy. In our study, we designed eSOMA-DM1, a SMDC combining the SSTR2-targeted octreotate peptide and the cytotoxic agent DM1 via a chelate-bridged linker (N3-Py-DOTAGA). This approach warrants conjugation of the targeting vector and the drug at opposite sites to avoid undesired steric hindrance effects. Methods: Synthesis of the DM1 moiety (4) involved a three-step synthetic route, followed by the conjugation to the cyclic peptide, N3-Py-DOTAGA-d-Phe-cyclo[Cys-Tyr-d-Trp-Lys-Thr-Cys]-Thr-OH, through a copper-free click reaction, resulting in eSOMA-DM1. Subsequent labeling with [111In]InCl3 gave a high radiochemical yield and purity. In vitro assessments of eSOMA-DM1 binding, uptake, and internalization were conducted in SSTR2-transfected U2OS cells. Ex vivo biodistribution and fluorescence imaging were performed in H69-tumor bearing mice. Results: eSOMA-DM1 exhibited an IC50 value for SSTR2 similar to the gold standard DOTA-TATE. The uptake of [111In]In-eSOMA-DM1 in U2OS.SSTR2 cells was 1.2-fold lower than that of [111In]In-DOTA-TATE. Tumor uptake in H69-xenografted mice was higher for [111In]In-eSOMA-DM1 at all-time points compared to [111In]In-DOTA-TATE. Prolonged blood circulation led to increased accumulation of [111In]In-eSOMA-DM1 in highly vascularized tissues, such as the lungs, skin, and heart. Excretion through the kidneys, liver, and spleen was also observed. Conclusion: eSOMA-DM1 is a SMDC developed for NET showing promising characteristics in vitro. However, the in vivo results obtained with [111In]In-eSOMA-DM1 suggest the need for adjustments to optimize its distribution.

Transvaginal double-layer parallel in-situ suturing for early complex vesicovaginal fistula repair: Case report.

Complex vesicovaginal fistulas (VVFs) with large defects pose significant surgical challenges. Traditional repair methods often require extensive tissue separation and multilayer suturing, risking local blood supply and healing. This study introduces a novel modified transvaginal repair technique that simplifies the procedure while preserving tissue vascularity. It employs double-layer parallel in situ suturing for early repair of complex VVF. A 50-year-old woman was admitted with continuous vaginal urine leakage for 4 days following trauma. Speculum examination revealed a 3-cm longitudinal oval laceration at the 11 o'clock position in the dorsal lithotomy site, with continuous fluid leakage through the fistula. Self-inflicted complex VVF. The patient underwent prophylactic placement of bilateral double-J stents and continuous catheterization, followed by surgical repair using a modified transvaginal technique involving double-layer parallel in situ suturing. Postoperative evaluations showed successful healing with no urinary leakage. The vaginal sutures were removed on day 24, and follow-up at 1 year confirmed no recurrence of the fistula or lower urinary tract symptoms, significantly improving the patient's quality of life. The modified transvaginal repair technique using double-layer parallel in situ suturing is a simple and effective approach for early repair of complex VVF, highlighting its potential for broader clinical application. Future studies with larger cohorts are needed to validate these findings.

Development and Biocompatibility Assessment of Decellularized Porcine Uterine Extracellular Matrix-Derived Grafts.

Biomaterials derived from biological matrices have been widely investigated due to their great therapeutic potential in regenerative medicine, since they are able to induce cell proliferation, tissue remodeling, and angiogenesis in situ. In this context, highly vascularized and proliferative tissues, such as the uterine wall, present an interesting source to produce acellular matrices that can be used as bioactive materials to induce tissue regeneration. Therefore, this study aimed to establish an optimized protocol to generate decellularized uterine scaffolds (dUT), characterizing their structural, compositional, and biomechanical properties. In addition, in vitro performance and invivo biocompatibility were also evaluated to verify their potential applications for tissue repair. Results showed that the protocol was efficient to promote cell removal, and dUT general structure and extracellular matrix composition remained preserved compared with native tissue. In addition, the scaffolds were cytocompatible, allowing cell growth and survival. In terms of biocompatibility, the matrices did not induce any signs of immune rejection invivo in a model of subcutaneous implantation in immunocompetent rats, demonstrating an indication of tissue integration after 30 days of implantation. In summary, these findings suggest that dUT scaffolds could be explored as a biomaterial for regenerative purposes, which is beyond the studies in the reproductive field.

Nanofat Improves Vascularization and Tissue Integration of Dermal Substitutes without Affecting Their Biocompatibility.

Dermal substitutes require sufficient tissue integration and vascularization to be successfully covered with split-thickness skin grafts. To rapidly achieve this, we provide the proof of principle for a novel vascularization strategy with high translational potential. Nanofat was generated from subcutaneous adipose tissue of green fluorescence protein (GFP)+ C57BL/6J donor mice and seeded onto small samples (4 mm in diameter) of the clinically approved dermal substitute Integra®. These samples and non-seeded controls were then implanted into full-thickness skin defects in the dorsal skinfold chamber of C57BL/6J wild-type mice and analyzed by intravital fluorescence microscopy, histology and immunohistochemistry over a 14-day period. Nanofat-seeded dermal substitutes exhibited an accelerated vascularization, as indicated by a significantly higher functional microvessel density on days 10 and 14 when compared to controls. This was primarily caused by the reassembly of GFP+ microvascular fragments inside the nanofat into microvascular networks. The improved vascularization promoted integration of the implants into the surrounding host tissue, which finally exhibited an increased formation of a collagen-rich granulation tissue. There were no marked differences in the inflammatory host tissue reaction to nanofat-seeded and control implants. These findings demonstrate that nanofat significantly improves the in vivo performance of dermal substitutes without affecting their biocompatibility.

Barrier-free, open-top microfluidic chip for generating two distinct, interconnected 3D microvascular networks

Developing microphysiological cell culture platforms with a three-dimensional (3D) microenvironment has been a significant advancement from traditional monolayer cultures. Still, most of the current microphysiological platforms are limited in closed designs, i.e. are not accessible after 3D cell culture loading. Here, we report an open-top microfluidic chip which enables the generation of two sequentially loaded 3D cell cultures without physical barriers restricting the nurture, gas exchange and cellular communication. As a proof-of-concept, we demonstrated the formation of two 3D vasculatures, one in the upper and the other in the lower compartment, under three distinct flow conditions: asymmetric side-to-center, symmetric side-to-center and symmetric center-to-side. We used computational modelling to characterize initial flow pressures in cell culture compartments. We showed prominent vessel formation and branched vasculatures in upper and lower cell culture compartments with interconnecting, lumenized vessels with in vivo-relevant diameter in all flow conditions. With advanced image processing, we quantified and compared the overall vascular network volume and the total length formed in asymmetric side-to-center, symmetric side-to-center and symmetric center-to-side flow conditions. Our results indicate that the developed chip can house two distinct 3D cell cultures with merging vessels between compartments and by providing asymmetric side-to-center or symmetric center-to-side flow vascular morphogenesis is enhanced in terms of overall network length. The developed open-top microfluidic chip may find various applications in generation of tissue-specific 3D-3D co-cultures for studying cellular interactions in vascularized tissues and organs.

Incidence And Risk Factors Of Retinopathy Of Prematurity: An Observational Study

Background: Retinopathy of prematurity is a condition where development of abnormal retinal vessels is secondary to an incomplete vascularization of retinal tissue due to hyperoxia, causing feedback inhibition of VEGF and destruction of endothelial cells. The risk factors of ROP should be identified to prevent disease development, and the knowledge of its etiology may help neonatologists and ophthalmologists perform careful screening and executive accurate diagnosis. In view of less literature on ROP in India, the current study was undertaken. Methods: This is a hospital-based observational study done on Neonates born at our tertiary care center- ASRAM Medical College, Eluru, Andhra Pradesh. The study was done for 6 months. Preterm infants having birth weight ≤ 1500g or gestational age ≤ 32 weeks or BW > 1500g or GA between 32 to 37 weeks with either respiratory distress syndrome, or sepsis, blood transfusions, and intraventricular hemorrhage were included. Results: ROP found in 21% infants. There is no significant difference in gender, mean gestational age between two grroups. Among 21 infants with ROP, 11 had stage 1 ROP, 8 had stage 2 and 2 had stage 3 ROP. There is significant difference in mean birth weight in between two groups. Conclusion: Impaired lung function (indicating the need for usage of surfactant) which may be, caused by pneumonia, bronchopulmonary dysplasia, or hyaline membrane disease, is an important risk factor for the development of ROP. ROP needs prompt therapeutic interventions to maintain high interest at this stage

A novel diode laser intervention in the management of external invasive cervical resorption

Abstract “Invasive cervical resorption (ICR)” is a rare category of “external root resorption.” It is a progressive and destructive condition with an unclear cause. Managing external “ICR” presents a significant challenge, even to the most seasoned dental professionals. The removal of excessively vascularized granulation tissue is viewed as a pivotal step. This case report highlights the use of a diode laser to excise granulation tissue, by achieving optimal tissue ablation, promoting better healing, and subsequently restoring the severely damaged crown of the external ICR tooth with an intracanal fiber post.

In vitro vascularization of 3D cell aggregates in microwells with integrated vascular beds

Most human tissues possess vascular networks supplying oxygen and nutrients. Engineering of functional tissue and organ models or equivalents often require the integration of artificial vascular networks. Several approaches, such as organs on chips and three-dimensional (3D) bioprinting, have been pursued to obtain vasculature and vascularized tissues in vitro. This technical feasibility study proposes a new approach for the in vitro vascularization of 3D microtissues. For this, we thermoform arrays of round-bottom microwells into thin non-porous and porous polymer films/membranes and culture vascular beds on them from which endothelial sprouting occurs in a Matrigel-based 3D extra cellular matrix. We present two possible culture configurations for the microwell-integrated vascular beds. In the first configuration, human umbilical vein endothelial cells (HUVECs) grow on and sprout from the inner wall of the non-porous microwells. In the second one, HUVECs grow on the outer surface of the porous microwells and sprout through the pores toward the inside. These approaches are extended to lymphatic endothelial cells. As a proof of concept, we demonstrate the in vitro vascularization of spheroids from human mesenchymal stem cells and MG-63 human osteosarcoma cells. Our results show the potential of this approach to provide the spheroids with an abundant outer vascular network and the indication of an inner vasculature.