Pharmacological safety of dimethoxy curcumin-human serum albumin conjugate for potential therapeutic purpose.

Medicinal properties of curcumin are widely published. Previously, researchers used curcuminoid mixture comprising three chemical forms, out of which, the highest quantity is the most active molecule-dimethoxy curcumin (DMC). Reduced bioavailability, poor aqueous solubility, and quick hydrolytic degradation of DMC have projected challenges limiting its therapeutic value. However, selective conjugation of DMC with human serum albumin (HSA) enhances drug stability and solubility by several folds. Studies using animal models demonstrated potential anti-cancer/anti-inflammatory effects of DMCHSA; both studies showed results of local administration in peritoneal cavity and rabbit knee joint. DMC has prospects as intravenous therapeutic agent because carrier is HSA. However, before in vivo testing, important preclinical data required are toxicological safety and bioavailability of soluble forms of DMC. This study evaluated absorption, distribution, metabolism, and excretion of DMCHSA. Imaging technology and molecular analysis proved bio-distribution. The study also assessed the pharmacological safety of DMCHSA in mice in terms of its acute and sub-acute toxicity, complying with regulatory toxicology. Overall, the study demonstrated the safety pharmacology of DMCHSA upon intravenous infusion. This is a novel study establishing the safety of highly soluble and stable formulation of DMCHSA, qualifying it for intravenous administration and further efficacy evaluation in suitable disease models.

Enriched adipose stem cell secretome as an effective therapeutic strategy for in vivo wound repair and angiogenesis.

The therapeutic potential of adipose tissue-derived mesenchymal stem cells (ADMSCs) is well studied for use in non-healing wounds. However, concerns on the transplantable cell number requirement, cell expansion, cell viability, retained cell multipotency and the limited cell implantation time for efficient impact hinders cell therapy. Recent literature is much inclined to the superiority of the ADMSCs' secretome, pre-dominating its paracrine-mediated therapeutic impact. In this context, the possibility of attaining accelerated wound angiogenesis through non-viral mediated enrichment of the ADMSCs secretome with pro-angiogenic growth factors (AGF) seems promising. Accordingly, this study aimed to explore the effect of AGF-enriched ADMSCs secretome for accelerating wound angiogenesis and repair in acute large area full thickness excision rabbit wound model, as adopted from Salgado et al. (Chir Buchar Rom 108:706-710, 1990). Using sub-dermal single-dose injections along the margin of the dorsal wound, native ADMSCs secretome, AGF-enriched ADMSC secretome, allogenic rabbit ADMSCs and a combination of AGF-enriched ADMSC secretome with allogenic rabbit ADMSCs were transplanted independently. Twenty-eight days (28 days) post-transplantation, histopathological analysis was performed to assess the effect. Hematoxylin and eosin (H&E) staining showed enhanced epithelization, notable granulation tissue and collagen fiber deposition in AGF-enriched secretome transplanted groups. This was confirmed by elevated CD31 detection, faster wound closure time and collagen organization. The use of single-dose AGF-enriched ADMSCs' secretome for therapeutic angiogenesis and wound repair seems to be a promising cell-free therapeutic option. Further investigations using multiple doses on larger animal groups remains to be explored in order to ascertain the comparative potential of AGF-enriched ADMSCs' secretome.

In vitro and In vivo toxicity analysis of zinc selenium/zinc sulfide (ZnSe/ZnS) quantum dots.

Despite the versatility of quantum dots (QDs) in optoelectronics and biomedical field, their toxicity risks remain a considerable hindrance for clinical applications. Cytotoxicity of Cadmium containing QDs is well documented and reveals that they are toxic to cells. Reports suggest that the presence of toxic elements at the QD core (e.g., cadmium, selenium) is responsible for its toxicity in in vivo and in vitro levels. Hence, here the toxicity of heavy metal free ZnSe/ZnS QDs on two scenarios were assessed, (i) HEK cells as in vitro system and (ii) Swiss Albino mice as in vivo model. Before toxicity analysis, QDs subjected to various optical and physico-chemical characterization methods such as absorption and emission spectra analysis, observation under U.V light, TEM, DLS, Zeta potential, FTIR, Raman and XPS spectra, ICP-OES, TGA and DTG curve. It is very necessary to characterize the synthesized QDs because their toxicity greatly influenced by the physico-chemical properties. On checking the vulnerability of HEK cells on exposure to ZnSe/ZnS QDs, the obtained results disclose that ZnSe/ZnS QDs showed merest impact on cellular viability at a concentration less than 100 µg/ml. Acute toxicity of 10 mg/kg ZnSe/ZnS QDs was studied in mice and no clinical or behavioural changes were observed. It did not induce any changes in haematological parameters and any loss of body or organ weight. Moderate pathological changes were evident only in the liver, all others organs like kidney, spleen and brain did not show any manifestations of toxicity. Current work lays substantial bedrock for safe biomedical and environmental application of ZnSe/ZnS QDs in near future.

Exploring Cadaver Skin For Standardization Of Rabbit And Porcine Burn Models In Research.

Burn animal models provide substantial insights into burn pathophysiology. Choice of the apt model is important for determining the clinical efficacy of new medicines. Therefore, standardization of burn models is crucial for scientific research. Use of common techniques like hot water, electricity and incandescent instruments to generate animal burn models is widely reported. However, great discrepancy in employed temperature and exposure times demands user-dependent standardization of the animal model prior to research. Establishment of custom generated in vivo burn models giving consideration to reduced use, suffering and risk of the experimental animal is equally crucial. Accordingly, this pilot study demonstrates a novel approach using rabbit and porcine cadaver skin for standardization of burn parameters prior to use in live animal models. Using a custom-made soldering iron coupled to a 16cm2 surface area copper plate, burns at randomly chosen temperatures of 80˚C and 120˚C, with exposure times ranging from 60s to 180s, were produced on rabbit and porcine cadaver skins. On gross and histopathological analysis, parameters required to generate characteristic changes for deep partial and full thickness burn involvement were established. The identified temperature and exposure time parameters were further validated in live animal models. In vivo validation established the success of this approach, highlighting reduced animal use, ease, reproducibility and efficacy in burn model standardization. The findings of this study will hopefully encourage researchers to opt for cadaver skin to determine parameters required to generate a specific degree of burn prior to its use in live animals for burn research.

Les modèles animaux permettent des avancées substantielles dans la compréhension de la physiopathologie des brûlures. Le choix du modèle est important pour évaluer l'efficacité de nouvelles thérapeutiques, donc la standardisation de ces modèles est cruciale. Les utilisations de l'eau chaude, de l'électricité et de solides chauds est couramment décrite. Cependant, la grande variabilité des températures et des temps de contact nécessite une calibration avant chaque étude expérimentale. Il est en outre nécessaire de développer des modèles in vivo à façon tout en réduisant le risque d'erreur et la souffrance animale. Cette étude décrit l'utilisation de peaux de lapins et de porcs morts pour la standardisation des modèles de brûlure les utilisant. Nous utilisons un fer à souder couplé à une plaque de cuivre de 16 cm², pouvant délivrer une température réglable entre 80 et 120°C pendant 60 à 180 s sur de la peau de lapin ou de porc morts. Nous avons défini les paramètres permettant de réaliser des brûlures intermédiaires ou profondes, objectivées par études macro- et microscopiques, validés ensuite chez l'animal vivant. Cette étape a permis de confirmer l'efficacité de cette approche qui réduit le nombre d'animaux d'expérience, est aisée et reproductible et bien corrélée à l'approche in vivo. Cette étude devrait conduire les équipes a réaliser une calibration ex vivo avant de réaliser une étude in vivo de brûlure expérimentale.

Organ distribution and biological compatibility of surface-functionalized reduced graphene oxide.

Graphene is an sp2 hybridized allotrope of carbon with a honeycomb lattice structure that has many applications in biomedicine owing to its unique physico-chemical properties. Graphene has attracted much interest from scientists for its biomedical potential, including in drug/gene delivery, fluorescent labeling of target analytes, tissue engineering, regenerative medicine and MRI contrast enhancement. However, there are very limited data available concerning the toxicity of graphene, and efforts have been made to study the bio-nano interactions of Pluronic functionalized reduced graphene oxide (rGO-P) in animal models. The present study aimed to evaluate the systemic toxicity of rGO-P and its ability to cross the blood-brain barrier in Swiss Albino mice subject to acute exposure to 10 mg kg-1 body weight of rGO-P. Prolonged exposure was evaluated in female Wistar rats by analyzing feto-placental transmission and any associated developmental neurotoxicity after intravenous administration of 5 mg kg-1 and 10 mg kg-1 body weight of rGO-P. Biodistribution analysis using confocal Raman mapping indicated that tiny amounts of rGO-P accumulated in major organs of both dams and pups, with no evident toxic response. The accumulation of rGO-P in various tissues of rat pups born to treated dams is ample evidence of feto-placental transmission. The present study clearly suggests that rGO-P is not toxic under any of the experimental conditions. These findings can therefore be carried forward for application of rGO-P in drug/gene delivery, early diagnosis and treatment of various diseases in neonates and adults. The results of the study show that rGO-P is an auspicious and promising material for future healthcare applications.

Investigation of chronic toxicity of hydroxyapatite nanoparticles administered orally for one year in wistar rats.

Although the toxicity/biocompatibility of hydroxyapatite nanoparticles (nano HA), a prospective nano biomaterial is extensively studied, its interaction on biological systems following chronic exposure is less exploited. In the present study, Wistar rats were given various concentrations of nano HA in the diet to determine the chronic toxicity and potential carcinogenicity. Altogether 140 rats were used for the study under various administration dosages along with control. The animals were sacrificed after 12months of controlled continuous dosing. All in-life parameters, including body weight, food consumption, clinical observations, survival, biochemical and hematology, were unaffected by the chronic exposure of nano HA orally. Similarly, gross and histopathological evaluation was also unchanged following exposure to nano HA. No evidence of nano HA-related lesions or Nano HA-induced neoplasia was suggested in this rodent bioassay study.

Chitosan-hyaluronic acid hydrogel for cartilage repair.

The current study investigates the potential of chitosan-hyaluronic acid dialdehyde hydrogels for in vivo cartilage regeneration following two different approaches: Gel alone for cartilage regeneration or combination of chondrocytes and gel for cartilage repair. Critical size osteochondral defects were created in knee joints of Newzealand White rabbits. Allogenic rabbit chondrocytes were encapsulated in hydrogels and gel or gel+cells were implanted in defects aseptically. The regenerated cartilage was analyzed after 12 weeks of implantation. The morphological scoring indicates that repair tissue was formed in all the animals by 12 weeks irrespective of whether they were sham, received gel, or gel with cells as implant. However the repair tissue formed in sham appeared fibrous and opaque, where as those that received gel had texture similar to the surrounding native cartilage and animals with gel+cells showed varied response. Histology staining, score distribution and immunostaining for collagen Type II showed animals that received gel alone as the implant had a mixture of hyaline and fibro cartilage. The animals with cell encapsulated gels had more fibrous cells with weak staining for collagen type II. There was no significant enhancement in the quality of regenerated cartilage in presence of encapsulated chondrocytes.

Preclinical evaluation of hydrogel sealed fluropassivated indigenous vascular prosthesis.

Background & objectives: Polyethylene terephthalate (PET) graft, designed and developed at our institute for vascular reconstruction, is porous to promote optimal incorporation and neointima formation, requiring pre-clotting or biomodification by sealing the pores before implantation. The objective of this study was to characterize, test and perform preclinical evaluation of hydrogel (alginate dialdehyde cross-linked gelatin) sealed fluoropassivated PET vascular prosthesis in pig model, so as to avoid pre-clotting, for its safety and efficacy before employing the indigenous and less expensive graft for clinical use. Methods: Hydrogel sealed, fluoropassivated PET vascular prosthesis were tested for haemocompatibility and toxicity followed by small animal toxicology tests and in vivo experiments in pigs receiving implantation at thoracic aorta. All 33 animals received test as well as control grafts with a plan for phased explantation at 2, 12 and 26 weeks. All animals underwent completion angiogram at the end of procedure as well as before graft explantation. Results: Haemocompatibility tests for haemolysis and toxicity tests showed no adverse events in tested mice and rabbits. Completion angiogram showed intact anastamosis and patent graft in each animal in post-operative period and at explantation. Gross and histopathological examination showed well-encapsulated grafts, clean glistening neointima and no evidence of thrombus in both test and control grafts. Interpretation & conclusions: Hydrogel sealed, fluoropassivated PET vascular prosthesis was found non-toxic, haemocompatible and remained patent in in vivo studies at planned intervals.

Long-term healing of mildly cross-linked decellularized bovine pericardial aortic patch.

Glutaraldehyde treated bovine pericardium is extensively used in cardiovascular surgery. However, frequent occurrence of failure modes, such as calcification and structural failure, has hard pressed the need for finding an alternate technology. Decellularized bovine pericardium is an emerging technology. Mildly cross-linked decellularized bovine pericardium promotes positive remodeling with insignificant calcification and acute inflammation. In the present study, mildly cross-linked decellularized bovine pericardium was evaluated as a cardiovascular patch by studying mechanical strength as well as graft remodeling, resistance to calcific degeneration and inflammatory response using long duration porcine aortic implantation. It was observed that decellularized bovine pericardium, although thinner and less elastic had equivalent tensile properties such as tensile strength and stiffness when compared to commercially available glutaraldehyde-treated bovine pericardium. It showed the potential for site appropriate remodeling evidenced by host cell incorporation, thinner neointima, graft degradation, and neocollagenisation making it suitable for vascular patch application, whereas glutaraldehyde-treated pericardium failed to integrate with host tissue through timely degradation and host cell incorporation or neocollagenization. Conversely, it elicited persistent acute inflammation and produced calcification. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2145-2152, 2017.

Toxicity, toxicokinetics and biodistribution of dextran stabilized Iron oxide Nanoparticles for biomedical applications.

Advancement in the field of nanoscience and technology has alarmingly raised the call for comprehending the potential health effects caused by deliberate or unintentional exposure to nanoparticles. Iron oxide magnetic nanoparticles have an increasing number of biomedical applications and hence a complete toxicological profile of the nanomaterial is therefore a mandatory requirement prior to its intended usage to ensure safety and to minimize potential health hazards upon its exposure. The present study elucidates the toxicity of in house synthesized Dextran stabilized iron oxide nanoparticles (DINP) in a regulatory perspective through various routes of exposure, its associated molecular, immune, genotoxic, carcinogenic effects and bio distribution profile. Synthesized ferrite nanomaterials were successfully coated with dextran (<25nm) and were physicochemically characterized and subjected to in vitro and in vivo toxicity evaluations. The results suggest that surface coating of ferrite nanoparticles with dextran helps in improvising particle stability in biological environments. The nanoparticles do not seem to induce oxidative stress mediated toxicological effects, nor altered physiological process or behavior changes or visible pathological lesions. Furthermore no anticipated health hazards are likely to be associated with the use of DINP and could be concluded that the synthesized DINP is nontoxic/safe to be used for biomedical applications.

Biocompatibility property of 100% strontium-substituted SiO2 -Al2 O3 -P2 O5 -CaO-CaF2 glass ceramics over 26 weeks implantation in rabbit model: Histology and micro-Computed Tomography analysis.

One of the desired properties for any new biomaterial composition is its long-term stability in a suitable animal model and such property cannot be appropriately assessed by performing short-term implantation studies. While hydroxyapatite (HA) or bioglass coated metallic biomaterials are being investigated for in vivo biocompatibility properties, such study is not extensively being pursued for bulk glass ceramics. In view of their inherent brittle nature, the implant stability as well as impact of long-term release of metallic ions on bone regeneration have been a major concern. In this perspective, the present article reports the results of the in vivo implantation experiments carried out using 100% strontium (Sr)-substituted glass ceramics with the nominal composition of 4.5 SiO2 -3Al2 O3 -1.5P2 O5 -3SrO-2SrF2 for 26 weeks in cylindrical bone defects in rabbit model. The combination of histological and micro-computed tomography analysis provided a qualitative and quantitative understanding of the bone regeneration around the glass ceramic implants in comparison to the highly bioactive HA bioglass implants (control). The sequential polychrome labeling of bone during in vivo osseointegration using three fluorochromes followed by fluorescence microscopy observation confirmed homogeneous bone formation around the test implants. The results of the present study unequivocally confirm the long-term implant stability as well as osteoconductive property of 100% Sr-substituted glass ceramics, which is comparable to that of a known bioactive implant, that is, HA-based bioglass.

Pre-clinical evaluation of titanium nitride coated titanium material.

The titanium nitride coated titanium is a material intended for the fabrication of left ventricular assist device. As per International standards, a material is subjected to pre-clinical evaluation before fabrication of a device. Toxicity/biocompatibility studies such as acute systemic toxicity, intracutaneous irritation, in vitro haemolysis and implantation in muscle were studied as per international standards for the titanium nitride coated titanium. Acute systemic toxicity was studied in mice using physiological saline and cotton seed oil extracts of the material. Intracutaneous irritation was done by injecting the extracts of the test material and control intradermally into rabbits. Grading of erythema and oedema of test and control animals were recorded at 24, 48 and 72 h. In vitro haemolysis was carried out with material and extract of the material with rabbit blood. The muscle implantation was carried out in nine anesthetized rabbits. The implanted animals were sacrificed at the end of 1, 4 and 12 weeks, the tissue with the implanted materials were collected and subjected to histopathological analysis. The results of the study did not show any significant irritation or systemic toxicity with physiological saline and cotton seed oil extracts of the material. The percentage of hemolysis induced by the material and extract was under acceptable range. Results of the histopathological evaluation suggest that the test material did not produce any cellular changes. Hence the present study concluded that the test material is non-toxic, non-irritant, non-haemolytic and biocompatible.