Transforming native exosomes to engineered drug vehicles: A smart solution to modern cancer theranostics.

Exosomes have been the hidden treasure of the cell in terms of cellular interactions, transportation and therapy. The native exosomes (NEx) secreted by the parent cells hold promising aspects in cancer diagnosis and therapy. NEx has low immunogenicity, high biocompatibility, low toxicity and high stability which enables them to be an ideal prognostic biomarker in cancer diagnosis. However, due to heterogeneity, NEx lacks specificity and accuracy to be used as therapeutic drug delivery vehicle in cancer therapy. Transforming these NEx with their innate structure and multiple receptors to engineered exosomes (EEx) can provide better opportunities in the field of cancer theranostics. The surface of the NEx exhibits numeric receptors which can be modified to pave the direction of its therapeutic drug delivery in cancer therapy. Through surface membrane, EEx can be modified with increased drug loading potentiality and higher target specificity to act as a therapeutic nanocarrier for drug delivery. This review provides insights into promising aspects of NEx as a prognostic biomarker and drug delivery tool along with its need for the transformation to EEx in cancer theranostics. We have also highlighted different methods associated with NEx transformations, their nano-bio interaction with recipient cells and major challenges of EEx for clinical application in cancer theranostics.

Recent Advances in Cardiac Tissue Engineering for the Management of Myocardium Infarction.

Myocardium Infarction (MI) is one of the foremost cardiovascular diseases (CVDs) causing death worldwide, and its case numbers are expected to continuously increase in the coming years. Pharmacological interventions have not been at the forefront in ameliorating MI-related morbidity and mortality. Stem cell-based tissue engineering approaches have been extensively explored for their regenerative potential in the infarcted myocardium. Recent studies on microfluidic devices employing stem cells under laboratory set-up have revealed meticulous events pertaining to the pathophysiology of MI occurring at the infarcted site. This discovery also underpins the appropriate conditions in the niche for differentiating stem cells into mature cardiomyocyte-like cells and leads to engineering of the scaffold via mimicking of native cardiac physiological conditions. However, the mode of stem cell-loaded engineered scaffolds delivered to the site of infarction is still a challenging mission, and yet to be translated to the clinical setting. In this review, we have elucidated the various strategies developed using a hydrogel-based system both as encapsulated stem cells and as biocompatible patches loaded with cells and applied at the site of infarction.

A critical appraisal of humanized alternatives to fetal bovine serum for clinical applications of umbilical cord derived mesenchymal stromal cells.

OBJECTIVE: The study is aimed to verify the possibility of using humanized alternatives to fetal bovine serum (FBS) such as umbilical cord blood plasma (CBP) and AB+ plasma to support the long-term growth of mesenchymal stromal cells (MSCs) derived from the umbilical cord. We hypothesized that umbilical CBP would be a potential substitute to FBS, especially for small scale autologous clinical transplantations. METHODS: The MSCs were cultured for six consecutive passages to evaluate xeno-free media's ability to support long-term growth. Cell proliferation rates, colony-forming-unit (CFU) efficiency and population doublings of expanded MSCs, were investigated. Ex vivo expanded MSCs were further characterized using flow cytometry and quantitative PCR. The impact of cryopreservation and composition of cryomedium on phenotype, viability of MSC was also assessed. RESULTS: Our results on cell proliferation, colony-forming unit efficiency suggested that the expansion of the cells was successfully carried out in media supplemented with humanized alternatives. MSCs showed lower CFU counts in FBS (~ 25) than humanized alternatives (~ 35). The gene expression analysis revealed that transcripts showed significant differential expression by two to three folds in the FBS group compared with MSCs grown in medium with humanized alternatives (p < 0.05). In addition, MSCs grown in a medium with FBS had more osteogenic activity, a signature of unwanted differentiation. The majority of ex vivo expanded MSCs at early and late passages expressed CD44+, CD73+, CD105+, CD90+, and CD166+ in all the experimental groups tested (~ 90%). In contrast to the other MSC surface markers, expression levels of STRO-1+ (~ 21-10%) and TNAP+ (~ 29-11%) decreased with the increase in passage number for MSCs cultured in a FBS-supplemented medium (p < 0.05). CONCLUSION: Our results established that CBP supported culture of umbilical cord tissue-derived MSCs and is a safer Xeno free replacement to FBS. The use of CBP also enables the storage of umbilical cord tissue derived MSCs in patient-specific conditions to minimize adverse events if cells are delivered directly to the patient.

Oncoplastic Breast Reconstruction in Breast Conservation Surgery: Improving the Oncological and Aesthetic Outcomes.

Breast conservation surgery (BCS) is now the standard of care for patients with early breast cancer. The main contraindications for BCS besides the presence of multicentricity and diffuse microcalcifications are inadequate tumour size to breast size ratio. With the advent of oncoplastic techniques, the indications of BCS may be further extended to patient with larger tumour size and or small volume breast. We prospectively assessed 42 patients undergoing oncoplastic breast conservation surgery for cosmetic and oncologic outcomes. Cosmetic outcome assessment was done by comparison of operated breast to contralateral breast by an independent surgeon, nurse and patient's attendant at 6 months post-surgery. Risk factors for compromised oncologic outcomes included grades II/III tumours and non-ductal histology. Intraoperative margin assessment with frozen section analysis proved to be important in order to achieve negative surgical margins on final histopathology. By univariate analysis, tumours located in central quadrant and medial half of the breast had similar cosmetic outcomes comparable to tumours located in other quadrants. Majority of our patients (90%) had overall good to excellent cosmetic outcomes on Harvard scale. Oncoplastic breast conservation surgery techniques allow for larger parenchymal resections without compromising oncologic and cosmetic results. It further allows extension of BCS to patients otherwise denied for the same based on earlier recommendations for mastectomy. Oncoplastic techniques and intraoperative margin assessment with frozen section are vital in attaining adequate margins and also decrease chance of local recurrence and revision surgery for positive margins.

A Patient-Inspired Ex Vivo Liver Tissue Engineering Approach with Autologous Mesenchymal Stem Cells and Hepatogenic Serum.

Design and development of ex vivo bioengineered liver tissue substitutes intended for subsequent in vivo implantation has been considered therapeutically relevant to treat many liver diseases that require whole-organ replacement on a long-term basis. The present study focus on patient-inspired ex vivo liver tissue engineering strategy to generate hepatocyte-scaffold composite by combining bone marrow mesenchymal stem cells (BMSCs) derived from cardiac failure patients with secondary hyperbilirubinemia as primers of hepatic differentiation and hepatocyte growth factor (HGF)-enriched sera from same individuals as hepatic inducer. A biodegradable and implantable electrospun fibrous mesh of poly-l-lactic acid (PLLA) and gelatin is used as supporting matrix (average fiber diameter = 285 ± 64 nm, porosity = 81 ± 4%, and average pore size = 1.65 ± 0.77 µm). The fibrous mesh supports adhesion, proliferation, and hepatic commitment of patient-derived BMSCs of adequate stemness using HGF-enriched sera generating metabolically competent hepatocyte-like cells, which is comparable to the hepatic induction with defined recombinant growth factor cocktail. The observed results confirm the combinatorial effects of nanofiber topography and biochemical cues in guiding hepatic specification of BMSCs. The fibrous mesh-hepatocyte construct developed in this study using natural growth factors and BMSCs of same individual is promising for future therapeutic applications in treating damaged livers.

Nanofibers coated on acellular tissue-engineered bovine pericardium supports differentiation of mesenchymal stem cells into endothelial cells for tissue engineering.

AIM: This study aimed to develop biodegradable, polymer-based nanofibers coated on acellular tissue-engineered bovine pericardium (ATEBP) for cell interfaces, enabling more exquisite functionality, such as mesenchymal stem cell (MSC) adhesion, proliferation and differentiation into endothelial cells for tissue engineering. MATERIALS & METHODS: ATEBP coated with nanofibers of poly(L-lactic acid)-co-poly(ε-caprolactone) (PLACL) and a blend of PLACL and gelatin were analyzed for human bone marrow-derived MSC adhesion, proliferation and differentiation into endothelial cells. RESULTS: The cell culture-based approach showed an increase in human bone marrow-derived MSC adhesion, proliferation and differentiation into endothelial cells on ATEBP coated with PLACL/gelatin nanofibers compared with ATEBP and PLACL nanofibers coated on ATEBP. CONCLUSION: ATEBP coated with PLACL/gelatin nanofibrous scaffolds, along with human bone marrow-derived MSCs differentiated into endothelial cells, might improve the scaffolds' functionality for tissue engineering.

Nanofiber-reinforced myocardial tissue-construct as ventricular assist device.

OBJECTIVES: This study aimed to create a myocardial tissue construct by tissue engineering to repair, replace, and regenerate damaged cardiac tissue. METHODS AND RESULTS: Human cardiac muscles harvested from a homograft heart retrieval system were decellularized followed by coating with electrospun nanofibers to make them amenable to scaffolding. These processed cardiac tissues were nourished in modified media having ischemic cardiac tissue conditioned media in 6 separate experimental variants, and cord blood mononuclear cells were injected into 4 of them. On the 17th day of culture, the nanofiber-coated scaffolds injected with mononuclear cells and/or reinforced by electrical and mechanical forces, started contracting spontaneously at varying rates, while the control remain noncontractile. Histological staining confirmed the pre-culture acellularity as well as post-culture stem cell viability, and revealed expression of troponin I and cardiac myosin. The acellular processed scaffold when implanted into sheep ischemic myocardial apex revealed transformation into sheep myocardium after 4 months of implantation. CONCLUSION: These results provide direct evidence for the re-cellularization of decellularized cardiac tissue grafts reinforced with a polymer nanofiber coating, by human mononuclear cells injection, leading to generation of a tissue-engineered myocardial construct.

In vitro hepatic trans-differentiation of human mesenchymal stem cells using sera from congestive/ischemic liver during cardiac failure.

Cellular therapy for end-stage liver failures using human mesenchymal stem cells (hMSCs)-derived hepatocytes is a potential alternative to liver transplantation. Hepatic trans-differentiation of hMSCs is routinely accomplished by induction with commercially available recombinant growth factors, which is of limited clinical applications. In the present study, we have evaluated the potential of sera from cardiac-failure-associated congestive/ischemic liver patients for hepatic trans-differentiation of hMSCs. Results from such experiments were confirmed through morphological changes and expression of hepatocyte-specific markers at molecular and cellular level. Furthermore, the process of mesenchymal-to-epithelial transition during hepatic trans-differentiation of hMSCs was confirmed by elevated expression of E-Cadherin and down-regulation of Snail. The functionality of hMSCs-derived hepatocytes was validated by various liver function tests such as albumin synthesis, urea release, glycogen accumulation and presence of a drug inducible cytochrome P450 system. Based on these findings, we conclude that sera from congestive/ischemic liver during cardiac failure support a liver specific microenvironment for effective hepatic trans-differentiation of hMSCs in vitro.

Polypropelene mesh eroding transverse colon following laparoscopic ventral hernia repair.

Polypropylene mesh when used in laparoscopic ventral hernia repair can produce the worst complication such as enterocutaneous fistula. We report an interesting case of incisional hernia operated with laparoscopic polypropylene mesh hernioplasty who subsequently developed an enterocutaneous fistula 1 month after surgery. A fistulogram showed dye entering into the transverse colon. On exploration, the culprit polypropylene mesh was found to have eroded into the mid-transverse colon causing the fistula. Resection and end-to-end anastomosis of the colon were done with the removal of the mesh. On literature review, polypropylene mesh erosion in to transverse colon is rare.

Inflammatory responses of tissue-engineered xenografts in a clinical scenario.

Acellular tissue-engineered (ATE) xenografts and homografts are used in clinical cardiovascular surgery. The present study examined the specific role of carbohydrate antigen (α-Gal and T-antigen) in immune response after decellularisation in tissue-engineered xenografts (porcine pulmonary artery and bovine jugular vein). An enzyme-linked immunosorbent assay (ELISA) was used to ascertain whether implantation of bioprostheses, ATE xenografts and mechanical valve replacement result in augmentation of anti-α-Gal IgM antibodies within eight days of surgery (each group, n=6). Kinetics of host inflammatory response on surgically explanted ATE xenografts was also studied. Immunostaining for α-Gal and T-antigen detected the presence of them in the native tissue but they were absent in processed ATE xenografts from the same tissue. A significant increase in the concentration of anti-α-Gal IgM antibodies was observed in the serum of bioprosthetic valve recipients as compared to ATE xenograft recipients (P<0.05). Organised collagen, and decreased inflammatory response with increase in endothelisation and vascularisation was evident beyond one year of surgery as compared to early periods in ATE xenografts. This study demonstrates that decellularisation of xenografts and further processing of these tissues enabled reduction of inflammatory stimulus with autologous recellularisation with no calcification.

High cholesterol diet increases MMP9 and CD40 immunopositivity in early atherosclerotic plaque in rabbits.

Inflammation is one of the important contributing factors for the development of atherosclerosis and heart disease. Inflammation leads to the mobilization of various cells in developing atherosclerotic plaque and simultaneously triggers the up-regulation of various cytokine secretions from effector cells. To understand early molecular events during atherosclerosis we developed a rabbit model in which male New Zealand White rabbits were fed high cholesterol diets for 12 weeks. Total cholesterol (TC), triglycerides (TG), low density lipoprotein-cholesterol (LDL-C) and high sensitivity C-reactive protein (hs-CRP) were significantly increased in the high cholesterol diet group when compared to the control group during the experimental period (P<0.05). In parallel, the immunolocalization of CD40, MMP9, S100, CD68, α-smooth muscle actin and von Willebrand factor (vWF) in developing atherosclerotic plaque of the aorta and carotid artery was increased in comparison with the controls fed with a regular diet (P<0.05). From the present study, we conclude that a high cholesterol diet up-regulates CD68 and CD40, which may play a possible role in the remodelling and destabilization of the atherosclerotic plaque of arteries with the up-regulation of MMP9 and hsCRP.