فهرست مطالب saeed farzad-mohajeri

Bone-marrow derived stem cells (BMSCs) can differentiate into several mesenchymal cell lines and are suitable candidates for bone and dental tissue engineering. This study aimed to assess the efficacy of cell therapy in direct pulp capping (DPC) of canine teeth using autologous BMSCs along with collagen/hydroxyapatite hybrid scaffold in terms of the quantity and quality of calcified bridge formation. The teeth were randomly divided into three groups of DPC with mineral trioxide aggregate (MTA), hydroxyapatite/collagen hybrid scaffold alone and BMSCs with hydroxyapatite/collagen hybrid scaffold; DPC was performed under general anesthesia in cavities prepared on the buccal surfaces of mandibular and maxillary premolars of the same dogs from which, stem cells had been isolated. All cavities were then restored with light-cure resin modified glass ionomer cement. Histomorphometric assessments after 12 weeks showed formation of dentinal bridge following DPC with BMSCs and MTA. The efficacy of MTA for calcified bridge formation following DPC was significantly higher than that of BMSCs plus hybrid scaffold (P<0.0001). According to present study, we concluded DPC using BMSCs and hybrid scaffold does not provide clinically noticeable results in canine patients.

The application of various strategies, including heat stress, has been attempted to maintain and improve mesenchymal stem cells (MSCs) plasticity and efficiency for bone regeneration. Although cell responses to heat stress are one of the most examined cellular stress responses, most studies, in this context, investigated the effect of that for a short period. Hence, the current study aimed to investigate the properties of MSCs, derived from dental pulp stem cells (DPSCs) following long-term heat stress.

DPSCs was loaded on β-tricalcium phosphate scaffold blocks and cultivated at elevated temperature up to 39 ° C. In vitro, DPSC properties, including proliferation, osteogenic differentiation, and bone regeneration in vivo, have been evaluated.

The results of in vitro study showed that mild heat stress for a lengthy period could maintain and improve both the proliferative and differentiation potential of DPSCs during in vitro expansion and differentiation. Also, bone regeneration in vivo showed increased bone regeneration in the cells cultivated at a higher temperature.

This study provided evidence for the beneficial effects of the administration of mild heat stress for an extended period to maintain and improve DPSC properties, which may serve as a starting point for developing clinically compliant procedures for MSC treatment before transplantation.

Mesenchymal stem cells (MSCs) have been utilized as an aid in regeneration of bone defects however due to the poor homing ability via systemic injection, local administration, genetic manipulation has been used more. The present study aimed to compare the local and systemic application of MSCs in regeneration of bone defects.

Sixty Wistar male rats were used in this study. Circular 5×5 mm bone defects were created in the angle of the mandible. Autogenous bone marrow mesenchymal stem cells (BMMSCs) were obtained and culture expanded. Green fluorescent positive (GFP+) transfection has been performed for the possible detection of the cells in the healed bone. The rats were randomly treated in four groups; 1. Beta tricalcium phosphate (β-TCP) scaffold seeded with MSC (β-TCP+MSC), 2. Intravenous MSC injection with β-TCP scaffold in the defect (MSC), 3. β-TCP without cell therapy (β-TCP) and 4. Control defects that left empty. The rats were euthanized after 8 weeks. New bone formation (BF) were investigated by hematoxylin and eosin staining.

Localized cell therapy (β-TCP+MSC group) showed the highest healing rate (BF= 54.05±2.39%) followed by MSC systemic injection (BF= 22.69±3.87%) (P≤0.05). Inflammatory cells infiltration was evident dominantly in systemic injection cell group. Immunohistchemical analysis showed existence of the MSCs around the defects. GFP+ cells were mainly detected in the defect in β-TCP+MSC group while few GFP+ cells were detected in the MSC systemic group.

local application of the MSCs with synthetic scaffold showed better results than intravenous administration of MSCs in treatment of rat mandible bone defects.

Minimally invasive methods are desirable and important for therapeutic purposes and animal modeling of intervertebral disc disease. Most  therapeutics and models are delivered and induced invasively rather than minimally invasively. Application of minimally invasive approaches in intervertebral disc, which is closed to critical structures, would be advantageous.

The objective of this study is to introduce and evaluate a new approach for percutaneous needle placement using computed tomography for injection and aspiration of the canine lumbar intervertebral disc.

This study was performed on eighteen healthy dogs in two different intervals. In each interval, three intervertebral discs were chosen and a spinal needle with suitable gauge were inserted at the center of the disc through the annulus fibrosus into the nucleus pulposus using computed tomography.

Accuracy and agility of needle placement showed better results with progression of study. The number of needle placement in proper position was one time minimally and three times maximally. Only in 10.2% of cases was minor hemorrhage observed in needle puncture site. The average time for placement of every needle was 141 s. No unexpected complication was observed.

Needle placement into the canine intervertebral disc could be applied in a simple and fast procedure for therapeutic and research purposes without any complication.

Minimally invasive methods are desirable and important for therapeutic purposes and animal modeling of intervertebral disc disease. Most  therapeutics and models are delivered and induced invasively rather than minimally invasively. Application of minimally invasive approaches in intervertebral disc, which is closed to critical structures, would be advantageous.

The objective of this study is to introduce and evaluate a new approach for percutaneous needle placement using computed tomography for injection and aspiration of the canine lumbar intervertebral disc.

This study was performed on eighteen healthy dogs in two different intervals. In each interval, three intervertebral discs were chosen and a spinal needle with suitable gauge were inserted at the center of the disc through the annulus fibrosus into the nucleus pulposus using computed tomography.

Accuracy and agility of needle placement showed better results with progression of study. The number of needle placement in proper position was one time minimally and three times maximally. Only in 10.2% of cases was minor hemorrhage observed in needle puncture site. The average time for placement of every needle was 141 s. No unexpected complication was observed.

Needle placement into the canine intervertebral disc could be applied in a simple and fast procedure for therapeutic and research purposes without any complication.

Stem cells have great effects in clinical cell-based therapy. Accordingly, controlling the behavior and directing the fate of stem cells cultured in the laboratory is an important issue.

The aim of this study was to evaluate osteogenic properties of adipose derived mesenchymal stem cells (ADSCs) which differentiated toward osteogenic linage by osteoblast-imprinted substrate.

Rat ADSCs seeded on osteoblast-imprinted substrates, alkaline phosphatase (ALP) were measured in cellular supernatant of days 7 and 14. Alizarin Red staining of mineral matrix production in day 17 was performed. In order for in vivo evaluation, after seeding differentiated cells on a simple collagen scaffold, samples were implanted in an 8mm critical size calvarial defect. After 4 weeks defect site was harvested and prepared for histopathological examination.

ALP in both time points was significantly more than in undifferentiated ADSCs. (p<0.05). Alizarin red staining of differentiated cells showed a great production of mineral matrix nodules in cell culture plate. Histopathological investigations revealed greater amount of new bone formation and mostly in the center of defect, indicate osteoinductive effect of differentiated cells in vivo.

The osteoblast-imprinted substrate can mimic the topography and shape of natural osteoblast, which can mechanically direct ADSCs toward osteogenesis.

Wound healing has been a major medical challenge in recent decades and it increase motivation of researchers to develop various therapeutic approaches. Along with the latest developments in science and technology, diverse approaches have been created and improved. Although Traditional management, including wound dressings and skin grafts, is still commonly used in current practice but newer technologies found their roles in wound management, such as using stem cells in skin grafts or combining traditional treatments with anti-bacterial nanoparticles. Various upcoming technologies, such as nanotechnology, biotechnology, stem cell therapy and telemedicine have emerged in recent years and are being used to assist wound healing, or even to replace traditional methods. However, many of these methods still lack assessment by large-scale studies and extensive application. Also, studies should design to explore cost-effectiveness, conveniency and efficacy of them. In this review, authors focus on and summarize recent developments involving hi-tech therapeutic methods that lead to both rapid healing and better cosmetic results.

Optimum healing of a cutaneous wound involves a cascade of biologic cellular and molecular processes. When the normal biological process fails for any reason, healing process can cease resulting in chronic wounds. In Addition, the body cannot repair some extensive wounds without problem. These Issues surrounding wound healing as well as increased medical healthcare in this field, developed novel wound therapies. Regardless of the type of these specific advanced wound care methods, the ideal goal would be to regenerate tissues such that both the structural and functional properties of the wounded tissue are restored to the levels before injury. Tissue engineering and stem cells may be the solution. A range of cell based therapies and tissue engineered scaffolds have begun to cross the rift from bench to bedside. These therapies have been heralded as a promising means by which to surpass current limitations in wound management. The wide differentiation potential of stem cells allows for the possibility of regenerating lost or damaged skin, while their ability to immunomodulate the wound bed from afar suggests that their clinical applications need not be restricted to direct tissue formation. The data suggests that the appropriate application of stem cells and scaffolds can accelerate wound healing. The clinical utility of stem cells and tissue engineering has been demonstrated across dozens of clinical trials in wound therapy.

Wound healing is an important concern in clinical medicine. Wound healing including skin wounds is a dynamic complicated procedure which involves many different molecular and cellular agents that occur after a tissue lesion in order to repair the injured tissue. Poor wound healing after trauma, surgery, or chronic disease such as diabetes affects human and animal life. Well understanding this process is necessary for developing therapeutic strategies and wound management to help treatment of normal healing procedure. The repair of wounded skin is included hemostasis and inflammation, proliferation, and maturation and remodeling. These steps have considerable overlaps with each other.

Objectives- The purpose of the study was to observe whether PRP, Mesenchymal Stem Cells (MSCs) and combining them could help make improvements the healing of Achilles tendons in rabbits.
Design- Experimental study.
Animals-Sixteen male, healthy and mature white New Zealand rabbits.
Procedures- The animals were randomiaed into 4 groups: Control, PRP, MSCs with fibrin glue and MSCs PRP therapy. A 3 mm diameter defect was created in the midsubstance of the medial M. gastrocnemius tendon in all rabbits. After 4 and 8 weeks, animals were euthanized (each time point, 2 rabbits of the each group) and samples were examined in term of histologic scoring with H & E and Masson's Trichrome.
Results- Histologic investigations confirmed that all 3 methods of treatment in Achilles tendon defect had suitable reparative effects. Final histologic scoring for control group at 4th week after operation was 4.5 in contrast to treatment groups (PRP =6, MSCs = 5.5 and MSCs PRP= 8). Final histologic scoring in all 4 groups improved at 8th week after operation (control=6.5, PRP =9.5, MSCs = 8.5 and MSCs PRP= 14.5).
Conclusion and Clinical Relevance- This study indicated that using PRP or MSCs treatment alone and combination of them in injured tendon improved healing process and decreased time of repair. Reparative effect of PRP in tendon defect was better than use of allogenic MSCs treatment. However, the combination of them caused the best results.

Objective- Investigate myocardial performance after autologous adipose-derived (ASCs) mesenchymal stem cell differentiated under equiaxial cyclic strain, transplantation in rabbits with acute myocardial infarction (AMI).
Design- Prospective, randomized experimental study
Animals- 20 New Zealand White rabbits (2-3 kg)
Procedure- ASCs were studied in four distinct groups of mechanical (ADM), chemical (ADC), undifferentiated (AD) and control (C) groups. According to this categorization, the cells were exposed to cyclic mechanical loading or 5-azacytidine as the chemical factor. 10 6 ASC cells were transplanted intramyocardially in rabbits with AMI (Acute Myocardial Infarction). Echocardiographic study was used to evaluate effects of cells on cardiac function.
Results- Left ventricle ejection fraction (LVEF) was significantly increased in the ADM (mechanically-differentiated adipose-derived mesenchymal stem cell) group at 2 months follow-up. Fractional shortening (FS) also showed a similar pattern as LVEF and increased in ADM group in compare to control and AD (undifferentiated adipose-derived mesenchymal stem cell) group.
Conclusion and clinical prevalence- The results indicate that intramyocardial transplantation of mechanically-differentiated ASCs improves cardiac function of ischemic myocardium. Transplantation of mechanically-differentiated ASCs for myocardial regeneration may become the future therapy for acute myocardial infarction.

Healing of Critical-Sized Defects (CSDs) is one of the major challenges facing orthopedic surgeons. To assess the bone healing process usually plain radiography is used. Serial radiography results in certain side effects and recent findings are indicating the early detection of bone healing via ultrasonography. The purpose of current study is to compare the diagnostic accuracy of radiography and ultrasonography in healing process of radial CSDs in rabbit. Sixteen New Zealand White Rabbits were used in this study. The radial CSDs of 15 mm size were created in a routine surgical procedure described previously and the two diagnostic tools were compared 12 weeks post-surgery. In case of obtaining different results from radiology and ultrasonography, to determine which diagnostic imaging method is of more accuracy, the histopathologic results of samples from the same day were used. In 15 cases of 16, ultrasonography findings were confirmed by radiography and only in one case they were in contradiction, in which radiographs showed an Atrophic Nonunion while Ultrasound detected an outstanding filled defect with a reverberation artifact underneath. In histopathology, the defect was filled with an osteoid matrix of high cellularity and calcification was obvious in some regions, confirming the ultrasound results. This study indicates that in diagnostic imaging of CSDs, the ultrasonography and radiography are usually consonant and even ultrasound is more accurate than radiology. In addition, in case of detection of a reverberation artifact and lack of any healing-related finding in radiography, this artifact may be an indication of osteoid matrix formation.

Case Description: Two female domestic short-hair cats Clinical The cats with clinical signs of regurgitation, dysphagia and respiratory distress were presented. Symptomatic sliding hiatal hernia was diagnosed by radiography in these cats. Treatment and Outcome: The hernias were corrected surgically by only left-sided fundic gastropexy in one, and by reduction of hiatal opening and gatropexy in the other. Both animals were asymptomatic on re-examination and follow-up studies two, six and twelve months post surgery. Clinical Relevance: This study revealed radiography and gastropexy as good diagnostic and treatment techniques, respectively in sliding hiatal hernia in cats.