Immunocytochemical characterization of in vitro PKH26-labelled and intracerebrally transplanted neonatal cells

Efficacy of stem cells versus microvesicles in ameliorating chronic renal injury in rats (histological and biochemical study)

Chronic exposure to heavy metals as aluminum chloride (AlCl3) could result in severe health hazards such as chronic renal injury. The present study aimed to evaluate the therapeutic potential of adipose tissue-derived stem cells (ASCs) in comparison to their microvesicles (MV) in AlCl3-induced chronic renal injury. Forty-eight adult male Wistar rats were divided into four groups: Control group, AlCl3-treated group, AlCl3/ASC-treated group, and AlCl3/MV-treated group. Biochemical studies included estimation of serum urea and creatinine levels, oxidative biomarkers assay, antioxidant biomarkers, serum cytokines (IL-1β, IL-8, IL-10, and IL-33), real time-PCR analysis of renal tissue MALT1, TNF-α, IL-6, and serum miR-150-5p expression levels. Histopathological studies included light and electron microscopes examination of renal tissue, Mallory trichrome stain for fibrosis, Periodic acid Schiff (PAS) stain for histochemical detection of carbohydrates, and immunohistochemical detection of Caspase-3 as apoptosis marker, IL-1B as a proinflammatory cytokine and CD40 as a marker of MVs. AlCl3 significantly deteriorated kidney function, enhanced renal MDA and TOS, and serum cytokines concentrations while decreased the antioxidant parameters (SOD, GSH, and TAC). Moreover, serum IL-10, TNF-α, miR-150-5p, and renal MALT1 expression values were significantly higher than other groups. Kidney sections showed marked histopathological damage in both renal cortex and medulla in addition to enhanced apoptosis and increased inflammatory cytokines immunoexpression than other groups. Both ASCs and MVs administration ameliorated the previous parameters levels with more improvement was detected in MVs-treated group. In conclusion: ASCs-derived MVs have a promising ameliorating effect on chronic kidney disease.

Electric field-directed migration of mesenchymal stem cells enhances their therapeutic potential on cisplatin-induced acute nephrotoxicity in rats

Cisplatin is widely used as an anti-neoplastic agent but is limited by its nephrotoxicity. The use of mesenchymal stem cells (MSCs) for the management of acute kidney injury (AKI) represents a new era in treatment but effective homing of administered cells is needed. This study aimed to investigate the effect of bone marrow-derived mesenchymal stem cells (BM-MSCs) on cisplatin-induced AKI in rats after directed migration by electric field (EF). Forty-eight adult male albino rats were equally classified into four groups: control, cisplatin-treated, cisplatin plus BM-MSCs, and cisplatin plus BM-MSCs exposed to EF. Serum levels of IL-10 and TNF-α were measured by ELISA. Quantitative real-time PCR analysis for gene expression of Bcl2, Bax, caspase-3, and caspase-8 was measured. Hematoxylin and eosin (H&E) staining, periodic acid Schiff staining, and immunohistochemical analysis were also done. MSC-treated groups showed improvement of kidney function; increased serum levels of IL-10 and decreased levels of TNF-α; and increased mRNA expression of Bcl2 and decreased expression of Bax, caspase-3, and caspase-8 proteins comparable to the cisplatin-injured group. EF application increased MSCs homing with significant decrease in serum urea level and caspase-3 gene expression together with significant increase in Bcl2 expression than occurred in the MSCs group. Restoration of normal kidney histomorphology with significant decrease in immunohistochemical expression of caspase-3 protein was observed in the BM-MSCs plus EF group compared to the BM-MSCs group. EF stimulation enhanced the MSCs homing and improved their therapeutic potential on acute cisplatin nephrotoxicity.

Therapeutic role of adipose tissue-derived stem cells versus microvesicles in a rat model of cerebellar injury

Monosodium glutamate (MSG) is a controversial food additive reported to cause negative effects on public health. Adipose stem cells (ASCs) and their derived vesicles (MVs) represent a promising cure for human diseases. This work was planned to compare the therapeutic effects of adipose stem cells and microvesicles in MSG-induced cerebellar damage. Forty adult healthy male Wister rats were equally divided into four groups: Group I (control group), group II (MSG-treated), group III (MSG/ASCs-treated), and group IV (MSG/MVs-treated). Motor behaviour of rats was assessed. Characterization of ASCs and MVs was done by flow cytometry. The cerebellum was processed for light and electron microscopic studies, and immunohistochemical localization of PCNA and GFAP. Morphometry was done for the number of Purkinje cells in H&E-stained sections, area per cent of GFAP immune reactivity and number of positive PCNA cells. Our results showed MSG-induced deterioration in the motor part. Moreover, MSG increases oxidant and apoptotic with decreases of antioxidant biomarkers. Structural changes in the cerebellar cortex as degeneration of nerve cells and gliosis were detected. There were also a decrease in the number of Purkinje cells, an increase in the area per cent of GFAP immune reactivity and a decrease in the number of positive PCNA cells, as compared to the control. Rats treated with ASCs showed marked functional and structural improvement in comparison with MV-treated rats. Thus, both ASCs and MVs had therapeutic potential for MSG-induced cerebellar damage with better results in case of ASCs.

Mesenchymal stem cells enhance AQP1 expression in the sublingual salivary gland of ovariectomized menopausal rat model

BACKGROUND

Ovariectomized menopausal rat model was used to investigate the effects of menopause on the sublingual salivary gland (SSG) and the potential therapeutic effect of human umbilical cord blood mesenchymal stem cells (hUCB-MSCs).

METHODS

Thirty rats were equally divided into three groups: sham-operated (SHAM), ovariectomized (OVX), and ovariectomized stem cells injected (OVX+ hUCB-MSCs). Expressions of α-SMA, AQP1, Sca-1, PCNA, ssDNA, and caspase-3 were determined. Homing of hUCB-MSCs was detected by fluorescence microscopy and examination of immunostained sections for human CD105 and CD34 was performed. Morphometric data were statistically analyzed using the Kruskal-Wallis test followed by Scheffé's method. Correlation of AQP1 with Sca-1-positive sublingual stem cells was also analyzed.

RESULTS

In the SSGs of the OVX group, ballooned mucus acinar cells, atrophied serous cells, and a decreased number and height of duct lining cells were observed. The interstitial spaces were edematous, and the blood vessels were congested. The significant decrease in the positive area % of α-SMA and AQP1, the number of Sca-1-positive sublingual stem cells, and proliferating cells was associated with a significant increase in apoptotic cells. The OVX+hUCB-MSCs group showed significant structural improvement, manifested by the normal appearance of mucus and serous acini, as well as the number and height of striated duct cells. A significant increase in the positive area % of α-SMA and AQP1 and the number of proliferating and Sca-1-positive sublingual stem cells was observed. Interestingly, a significantly positive Pearson's correlation between the area % of AQP1 and the number of Sca-1-positive sublingual stem cells was also recorded.

CONCLUSION

Our results indicated a positive effect of hUCB-MSCs therapy for SSG pathology in a post ovariectomy rat model as evidenced by an improvement in the histologic architecture, upregulation of the immunostained area % of α-SMA and AQP1, increase in the number of Sca-1-positive sublingual stem cells and proliferating cells, and downregulation of apoptotic cells.

Bone Marrow-Derived Mesenchymal Stem Cells Ameliorate the Pancreatic Changes of Chemically Induced Hypothyroidism by Carbimazole in Male Rats

We induced hypothyroidism (HT) in male rats through chronic oral administration of carbimazole and then tested whether an i.v. injection of rat bone marrow-derived mesenchymal stem cells (BM-MSCs) could ameliorate the HT-induced changes in pancreatic structure and function. The thyroid and pancreatic function tests, as well as total antioxidant capacity (TAC) and malondialdehyde (MDA) were estimated. The pancreatic structure was evaluated by hematoxylin and eosin (H&E) stain. Insulin protein and cleaved caspase-3 were detected immunohistochemically. The degree of apoptosis was assessed by TUNEL assay. The morphometric measurements were done by an image analyzer system and the obtained data were statistically analyzed. HT rats showed hyperglycemia associated with insulin deficiency, decreased TAC and increased MDA levels. H&E-stained sections showed that the pancreatic septa were infiltrated with acidophilic material. Some acini were vacuolated while others showed depleted acidophilia and dilated lumina. Spindle-shaped cells were accumulated within deformed islets in HT rats. The positive reaction with anti-cleaved caspase-3 was exclusively noted in the cytoplasm of islet cells with no immunostaining reaction in the acinar and ductal cells, whereas the positively stained nuclei with TUNEL were demonstrated in the islet and acinar cells. A significant increase in the apoptotic index % of both markers was detected. Injection of BM-MSCs in HT rats restored all biochemical indicators of disturbed pancreatic function to normal level and improved pancreatic structure, resulting in a clear septa and normal appearance of acini and islets. In conclusion, many of the significant structural and func tional pancreatic alterations detected in HT rats were ameliorated after the injection of BM-MSCs. These data demonstrate the ability of BM-MSCs to repair pancreatic disturbances. Further studies on humans are necessary to determine the potential clinical applications of BM-MSCs.

Fluoxetine pretreatment enhances neurogenic, angiogenic and immunomodulatory effects of MSCs on experimentally induced diabetic neuropathy

Being one of the most debilitating complications among diabetic patients, diabetic polyneuropathy (DPN) is a paramount point of continuous research. Stem cell therapies have shown promising results. However, limited cell survival and paracrine activities hinder its transfer from bench to bedside. We designed this study to evaluate fluoxetine-pretreatment technique of mesenchymal stem cells (MSCs) as an approach to enhance their paracrine and immunomodulatory properties in DPN. Effects of fluoxetine treatment of MSCs were tested in vitro. Forty-two adult Wistar male albino rats were utilized, further subdivided into control, diabetic, MSC-treated and fluoxetine-pretreated MSC groups. Sciatic nerve sections were prepared for light and electron microscope examination and immunohistochemical detection of neurofilament (NF) protein. Also, we assessed in vitro survival and paracrine properties of fluoxetine-pretreated MSCs. Real time PCR of BDNF, VEGF, IL-1β, and IL-10 expression in tissue homogenate was performed. Our results showed restoration of normal neuronal histomorphology and ultrastructure, moreover, immunohistochemical expression of anti-neurofilament protein was significantly elevated in MSC-treated groups compared to the diabetic one. Fluoxetine enhanced the MSC survival and their paracrine properties of MSCs in vitro. Furthermore, the fluoxetine-pretreated MSC group revealed a significant elevation of mRNA expression of BDNF (neurotrophic factor) and VEGF (angiogenic factor), denoting ameliorated MSC paracrine properties. Similarly, improved immunomodulatory functions were evident by a significant reduction of interleukin-1β mRNA expression (pro-inflammatory) and a reciprocal significant increase of interleukin-10 (anti-inflammatory). We concluded that fluoxetine-pretreatment of MSCs boosts their survival, paracrine, and immunomodulatory traits and directly influenced neuronal histomorphology. Hence, it presents a promising intervention of diabetic polyneuropathy. Graphical Abstract.

Effect of Exosomes from Rat Adipose-Derived Mesenchymal Stem Cells on Neurite Outgrowth and Sciatic Nerve Regeneration After Crush Injury

Peripheral nerve injury requires optimal conditions in both macro-environment and microenvironment for promotion of axonal regeneration. However, most repair strategies of traumatic peripheral nerve injury often lead to dissatisfying results in clinical outcome. Though various strategies have been carried out to improve the macro-environment, the underlying molecular mechanism of axon regeneration in the microenvironment provided by nerve conduit remains unclear. In this study, we evaluate the effects of from adipose-derived mesenchymal stem cells (adMSCs) originating exosomes with respect to sciatic nerve regeneration and neurite growth. Molecular and immunohistochemical techniques were used to investigate the presence of characteristic exosome markers. A co-culture system was established to determine the effect of exosomes on neurite elongation in vitro. The in vivo walking behaviour of rats was evaluated by footprint analysis, and the nerve regeneration was assessed by immunocytochemistry. adMSCs secrete nano-vesicles known as exosomes, which increase neurite outgrowth in vitro and enhance regeneration after sciatic nerve injury in vivo. Furthermore, we showed the presence of neural growth factors transcripts in adMSC exosomes for the first time. Our results demonstrate that exosomes, constitutively produced by adMSCs, are involved in peripheral nerve regeneration and have the potential to be utilised as a therapeutic tool for effective tissue-engineered nerves.

[Construction of tissue engineered cartilage based on acellular cartilage extracellular matrix oriented scaffold and chondrocytes]

Objective

To observe the feasibility of acellular cartilage extracellular matrix (ACECM) oriented scaffold combined with chondrocytes to construct tissue engineered cartilage.

Methods

Chondrocytes from the healthy articular cartilage tissue of pig were isolated, cultured, and passaged. The 3rd passage chondrocytes were labeled by PKH26. After MTT demonstrated that PKH26 had no influence on the biological activity of chondrocytes, labeled and unlabeled chondrocytes were seeded on ACECM oriented scaffold and cultivated. The adhesion, growth, and distribution were evaluated by gross observation, inverted microscope, and fluorescence microscope. Scanning electron microscope was used to observe the cellular morphology after cultivation for 3 days. Type Ⅱ collagen immunofluorescent staining was used to check the secretion of extracellular matrix. In addition, the complex of labeled chondrocytes and ACECM oriented scaffold (cell-scaffold complex) was transplanted into the subcutaneous tissue of nude mouse. After transplantation, general physical conditions of nude mouse were observed, and the growth of cell-scaffold complex was observed by molecular fluorescent living imaging system. After 4 weeks, the neotissue was harvested to analyze the properties of articular cartilage tissue by gross morphology and histological staining (Safranin O staining, toluidine blue staining, and typeⅡcollagen immunohistochemical staining).

Results

After chondrocytes that were mainly polygon and cobblestone like shape were seeded and cultured on ACECM oriented scaffold for 7 days, the neotissue was translucency and tenacious and cells grew along the oriented scaffold well by inverted microscope and fluorescence microscope. In the subcutaneous microenvironment, the cell-scaffold complex was cartilage-like tissue and abundant cartilage extracellular matrix (typeⅡcollagen) was observed by histological staining and typeⅡcollagen immunohistochemical staining.

Conclusion

ACECM oriented scaffold is benefit to the cell adhesion, proliferation, and oriented growth and successfully constructes the tissue engineered cartilage in nude mouse model, which demonstrates that the ACECM oriented scaffold is promise to be applied in cartilage tissue engineering.

Bone marrow-derived mesenchymal stem cells ameliorate parotid injury in ovariectomized rats

BACKGROUND AIMS

Parotid hypofunction causes life-disrupting effects, and there are no effective medications for xerostomia. We hypothesized that mesenchymal stem cells (MSCs) have repairing effects on parotid glands of ovariectomized (OVX) rats.

METHODS

Forty-five adult female rats were divided into three equal groups: group I (Control group), group II (OVX-group) and group III (OVX rats that received MSCs at 4 and 8 weeks post-ovariectomy). At 12 weeks post-ovariectomy, histological (Masson's trichrome and periodic acid-Schiff with alcian blue stains), immunohistochemical (caspase-3 and CD44) and morphometric studies and salivary flow rate and saliva pH determination were carried out.

RESULTS

Histologically, the OVX group displayed numerous irregular vacuolated acini, thickened septa with marked cellular infiltration and vascular congestion. Degenerated organelles and few or irregular secretory granules with a different density were observed. Caspase-3-positive cells were highly expressed. MSC-treated glands exhibited a considerable degree of preservation of glandular architecture with numerous CD44-expressing and few caspase-3-expressing cells. Significant decrease of the salivary flow rate in the OVX group was detected, which reverted to normal levels in group III.

CONCLUSIONS

MSCs ameliorated the damaging effects of ovariectomy on the parotid glands.

In vivo imaging system for explants analysis-A new approach for assessment of cell transplantation effects in large animal models

Introduction

Despite spectacular progress in cellular transplantology, there are still many concerns about the fate of transplanted cells. More preclinical studies are needed, especially on large animal models, to bridge the translational gap between basic research and the clinic. Herein, we propose a novel approach in analysis of cell transplantation effects in large animals explants using in vivo imaging system (IVIS®) or similar equipment.

Material and methods

In the in vitro experiment cells labeled with fluorescent membrane dyes: DID (far red) or PKH26 (orange) were visualized with IVIS®. The correlation between the fluorescence signal and cell number with or without addition of minced muscle tissue was calculated. In the ex vivo study urethras obtained from goats after intraurethral cells (n = 9) or PBS (n = 4) injections were divided into 0.5 cm cross-slices and analyzed by using IVIS®. Automatic algorithm followed or not by manual setup was used to separate specific dye signal from tissue autofluorescence. The results were verified by systematic microscopic analysis of standard 10 μm specimens prepared from slices before and after immunohistochemical staining. Comparison of obtained data was performed using diagnostic test function.

Results

Fluorescence signal strength in IVIS® was directly proportional to the number of cells regardless of the dye used and detectable for minimum 0.25x10⁶ of cells. DID-derived signal was much less affected by the background signal in comparison to PKH26 in in vitro test. Using the IVIS® to scan explants in defined arrangement resulted in precise localization of DID but not PKH26 positive spots. Microscopic analysis of histological specimens confirmed the specificity (89%) and sensitivity (80%) of IVIS® assessment relative to DID dye. The procedure enabled successful immunohistochemical staining of specimens derived from analyzed slices.

Conclusions

The IVIS® system under appropriate conditions of visualization and analysis can be used as a method for ex vivo evaluation of cell transplantation effects. Presented protocol allows for evaluation of cell delivery precision rate, enables semi-quantitative assessment of signal, preselects material for further analysis without interfering with the tissue properties. Far red dyes are appropriate fluorophores to cell labeling for this application.

Therapeutic efficacy of bone marrow derived mesenchymal stromal cells versus losartan on adriamycin-induced renal cortical injury in adult albino rats

BACKGROUND

Renal disease is a major health problem. Recent studies have reported the efficacy of stem cell therapy in nephropathy animal models.

AIM OF THE WORK

This study was designed to investigate the therapeutic effectiveness of bone marrow-derived mesenchymal stromal cells (MSCs) versus losartan in the treatment of renal alterations induced by adriamycin (ADR).

MATERIALS AND METHODS

Thirty-five adult male albino rats were divided into four groups. Group I was the control group. Group II (adriamycin-treated group),which included ten rats that were injected with a single dose of adriamycin (15 mg/kg) intraperitoneally, was subdivided into subgroup IIa and IIb and they were sacrificed 1 week and 5 weeks after adriamycin injection, respectively. Group III was the adriamycin + losartan-treated group and 1 week after adriamycin injection five rats received 10 mg/kg of losartan orally and daily for 4 weeks. Group IV was the adriamycin + MSC-treated group); five rats were injected with adriamycin as group II then supplied with MSCs at a dose of 1 × 10(6) cells suspended in 0.5 mL of phosphate-buffered saline (PBS) per rat in the tail vein 1 week after adriamycin injection. Rats of this group were sacrificed 4 weeks after the stem cell injection. Blood urea nitrogen and serum creatinine were measured. Samples from renal cortex were processed for light and electron microscope examination. As regards light microscope, sections were stained with hematoxylin and eosin (H-E), periodic acid-Schiff (PAS), masson trichrome, proliferating cell nuclear antigen (PCNA) and Caspase-3 immunohistochemical stains. Morphometrical and statistical analyses were also conducted.

RESULTS

Examination of adriamycin-treated group revealed deterioration of renal functions and various degrees of renal structural alterations as vacuolated cytoplasm, dark nuclei and detached epithelial lining. Administration of losartan partially improved ADR-induced kidney dysfunction, whereas MSCs denoted a more ameliorative role evidenced by structural and functional recovery.

CONCLUSION

MSCs have a relevant therapeutic potential against ADR-induced renal damage. MSCs may accomplish this role by decreasing caspase-3 expression and increasing proliferating cell nuclear antigen staining which influence the regeneration of the kidney.

Therapeutic potentials of mesenchymal stem cells on the renal cortex of experimentally induced hypertensive albino rats: Relevant role of Nrf2

Bone marrow derived-mesenchymal stem cells (BM-MSCs) have brought great attention in regenerative medicine field, various experimental & clinical trials were held to investigate their therapeutic effects in different disorders. We designed a histological & immunohistochemical study to evaluate effectiveness of MSCs therapy in withhold of end-stage renal disease (ESRD) secondary to hypertension which has become a growing & striking public health problem. 30 adult male albino rats were utilized, 20 of them were exposed to experimental induction of hypertension, then divided equally to MSCs treated group (injected with 1×10⁶ fluorescent labeled cell i.v./rat), while the second one was left without treatment. Renal specimens were subjected to histopathological, ultrastructural and immunohistochemical examination for Nrf2 in addition to biochemical estimation of serum urea & creatinine. Our results documented that BM-derived MSCs exerts considerable reversing effect of histopathologic and ultrastructural hypertensive nephropathy. Moreover, immunohistochemical results clearly pointed to relevant role of Nrf2 pathway in MSCs related renal therapeutic effects.

Effect of mesenchymal stem cells on induced skeletal muscle chemodenervation atrophy in adult male albino rats

The present research was conducted to evaluate the effect of bone marrow derived mesenchymal stem cells (BM-MSCs) as a potential therapeutic tool for improvement of skeletal muscle recovery after induced chemodenervation atrophy by repeated local injection of botulinum toxin-A in the right tibialis anterior muscle of adult male albino rats. Forty five adult Wistar male albino rats were classified into control and experimental groups. Experimental group was further subdivided into 3 equal subgroups; induced atrophy, BM-MSCs treated and recovery groups. Biochemical analysis of serum LDH, CK and Real-time PCR for Bcl-2, caspase 3 and caspase 9 was measured. Skeletal muscle sections were stained with H and E, Mallory trichrome, and Immunohistochemical reaction for Bax and CD34. Improvement in the skeletal muscle histological structure was noticed in BM-MSCs treated group, however, in the recovery group, some sections showed apparent transverse striations and others still affected. Immunohistochemical reaction of Bax protein showed strong positive immunoreaction in the cytoplasm of muscle fibers in the induced atrophy group. BM-MSCs treated group showed weak positive reaction while the recovery group showed moderate reaction in the cytoplasm of muscle fibers. Immunohistochemical reaction for CD34 revealed occasional positive CD34 stained cells in the induced atrophy group. In BM-MSCs treated group, multiple positive CD34 stained cells were detected. However, recovery group showed some positive CD34 stained cells at the periphery of the muscle fibers. Marked improvement in the regenerative capacity of skeletal muscles after BM-MSCs therapy. Hence, stem cell therapy provides a new hope for patients suffering from myopathies and severe injuries.

Therapeutic effect of mesenchymal stem cells on experimentally induced hypertensive cardiomyopathy in adult albino rats

Hypertensive heart diseases affect millions of people worldwide. We aimed to investigate the hypertensive left ventricular histological changes and assess the effectiveness of bone marrow derived mesenchymal stem cells (MSCs) therapy in the treatment of hypertensive cardiomyopathy. Adult male albino rats were assigned into two groups: group I (control), group II (Experimental) subdivided into subgroup IIa (hypertensive) and subgroup IIb (stem cell therapy). Left ventricles (LVs) were processed for light and electron microscope. Mallory's trichrome and immunostaining for caspase-3 and desmin were carried out. Hypertension caused left ventricular histological and immunohistochemical changes that had been effectively improved by MSCs therapy.

A Comparison of Exogenous Labels for the Histological Identification of Transplanted Neural Stem Cells

The interpretation of cell transplantation experiments is often dependent on the presence of an exogenous label for the identification of implanted cells. The exogenous labels Hoechst 33342, 5-bromo-2'-deoxyuridine (BrdU), PKH26, and Qtracker were compared for their labeling efficiency, cellular effects, and reliability to identify a human neural stem cell (hNSC) line implanted intracerebrally into the rat brain. Hoechst 33342 (2 mg/ml) exhibited a delayed cytotoxicity that killed all cells within 7 days. This label was hence not progressed to in vivo studies. PKH26 (5 μM), Qtracker (15 nM), and BrdU (0.2 μM) labeled 100% of the cell population at day 1, although BrdU labeling declined by day 7. BrdU and Qtracker exerted effects on proliferation and differentiation. PKH26 reduced viability and proliferation at day 1, but this normalized by day 7. In an in vitro coculture assay, all labels transferred to unlabeled cells. After transplantation, the reliability of exogenous labels was assessed against the gold standard of a human-specific nuclear antigen (HNA) antibody. BrdU, PKH26, and Qtracker resulted in a very small proportion (<2%) of false positives, but a significant amount of false negatives (∼30%), with little change between 1 and 7 days. Exogenous labels can therefore be reliable to identify transplanted cells without exerting major cellular effects, but validation is required. The interpretation of cell transplantation experiments should be presented in the context of the label's limitations.

Differentiation of UC-MSCs into hepatocyte-like cells in partially hepatectomized model rats

The aim of the study was to investigate the possibility of human umbilical cord mesenchymal stem cells (UC-MSCs) surviving and differentiating into hepatocyte-like cells in partially hepatectomized model rats. MSCs were isolated from human umbilical cord and cultured with collagenase digestion. Cell surface markers were detected and fifth generation UC-MSCs were labeled with PKH26. The partially hepatectomized model rats were injected with the labeled human umbilical cord MSCs and transplanted through the portal vein. The survival of the labeled cells, in differentiation conditions and the expression of hepatic marker albumin were observed at post-transplantation 1, 2 and 3 weeks under a fluorescence microscope. It was found that the human umbilical cord MSCs could be cultured and amplified in vitro. Following transplantation to the partially hepatectomized liver of the model rat, the cells survived and expresses the hepatic marker albumin in vivo. After being labeled with PKH26, the cells were visualized as red fluorescence under a fluorescence microscope. In the frozen sections of the liver, the marked cells scattered around and most of them expressed albumin with green fluorescence under the fluorescence microscope. In conclusion, the transplanted human umbilical cord MSCs survived and differentiated into hepatocyte-like cells. The human umbilical cord MSCs may therefore be a main source of hepatocytes in transplantation.

Human embryonic mesenchymal stem cells participate in differentiation of renal tubular cells in newborn mice

Stem cells are used with increasing success in the treatment of renal tubular injury. However, whether mesenchymal stem cells (MSC) differentiate into renal tubular epithelial cells remains controversial. The aims of the present study were to observe the localization of human embryonic MSCs (hMSCs) in the kidneys of newborn mice, and to investigate hMSC differentiation into tubular epithelium. Primary culture hMSCs were derived from 4–7-week-old embryos and labeled with the cell membrane fluorescent dye PKH-26. The degree of apoptosis, cell growth, differentiation and localization of hMSCs with and without this label were then determined using immunohistochemical methods and flow cytometry. hMSCs and PKH26-labeled hMSCs were revealed to differentiate into chondrocytes and adipocytes, and were demonstrated to have similar proliferative capability. In the two cell types, the antigens CD34 and CD45, indicative of hematopoietic lineages, were not expressed; however, the expression of the mesenchymal markers CD29 and CD90 in MSCs, was significantly increased. During a 4-week culture period, laser confocal microscopy revealed that PKH26-labeled hMSCs in the kidneys of newborn mice gradually dispersed. Two weeks after the injection of the PKH26-labeled cells, the percentage of PKH26-labeled hMSCs localized to the renal tubules was 10±2.1%. In conclusion, PKH26 labeling has no effect on hMSC differentiation, proliferation and mesenchymal cell surface features, and hMSCs injected into the kidneys of newborn mice may transform to renal tubule epithelium.

Histological study on effect of mesenchymal stem cell therapy on experimental renal injury induced by ischemia/reperfusion in male albino rat

BACKGROUND AND OBJECTIVES

Acute kidney injury (AKI) represents a major clinical problem with high mortality and limited treatment protocols. This study was planned to evaluate the therapeutic effectiveness of bone marrow - derived mesenchymal stem cells (BM-MSCs) in a rat model of ischemia/reperfusion (I/R) AKI.

METHODS AND RESULTS

This study was carried out on thirty adult male albino rats. Animals were divided equally into three groups. Group I (control sham-operated group) (n=10), were subdivided equally into two subgroups; Ia and Ib. The experimental group (n=20) were all subjected to I/R injury by clamping both renal pedicles for 40 minutes. Half of the I/R animals did not receive MSC therapy (group II) [non-MSC treated group]. The other half of the I/R animals received single intravenous injection of PKH26 labelled BM-MSCs immediately after removal of the clamps and visual confirmation of reflow (group III) [MSC treated group]. Animals were sacrificed 24 hrs (subgroups IIa & IIIa) and 72 hrs (subgroups IIb & IIIb) after intervention. Serological measurements included serum urea and creatinine. Kidney specimens were processed for H&E, PAS and PCNA. Mean % of renal corpuscles with affected glomeruli, mean % of affected tubules, mean area % of PAS-positive reaction and mean area % of PCNA immunoreactivity were measured by histomorphometric studies and statistically compared. MSCs-treated group exhibited protection against renal injury serologically and histologically.

CONCLUSIONS

Results of the present study suggest a potential reno-protective capacity of MSCs which could be of considerable therapeutic promise for cell-based management of clinical AKI.

Biologic properties of gadolinium diethylenetriaminepentaacetic acid-labeled and PKH26-labeled human umbilical cord mesenchymal stromal cells

BACKGROUND AIMS

This study was conducted to characterize gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA)-labeled and PKH26-labeled human umbilical cord mesenchymal stromal cells (HuMSCs) and to track them with magnetic resonance imaging (MRI) in vitro and in vivo.

METHODS

HuMSCs were isolated from umbilical cords and expanded in vitro. Cells were sequentially labeled with Gd-DTPA and PKH26. The labeling efficiency was determined by spectrophotometry measurements, and the longevity of Gd-DTPA maintenance was measured with MRI. The influence of double labeling on cellular biologic properties was assessed by cell proliferation, viability, differentiation, cycle and apoptosis. Transplantation of double-labeled HuMSCs or placebo was performed in 39 female Sprague-Dawley rats. Leak point pressure and maximal bladder capacity were measured in animals 6 weeks after injection.

RESULTS

The T1 values and signal intensity on T1-weighted imaging of labeled cells were significantly higher than the control group (P < 0.05). The signal intensity on T1-weighted imaging of labeled cells was retained >14 days in vitro and in vivo. There was no significant difference in the cell cycle, cell apoptosis, cell proliferation and cell viability between labeled and unlabeled HuMSCs (P > 0.05). After double labeling, HuMSCs were still capable of differentiating into osteoblasts and adipocytes. Periurethrally injected HuMSCs in the rats significantly improved leak point pressure and maximal bladder capacity.

CONCLUSIONS

HuMSCs were successfully labeled with Gd-DTPA and PKH26. This labeling method is reliable and efficient and can be applied for tracking cells in vitro and in vivo without altering cellular biologic properties.

Simulated microgravity facilitates cell migration and neuroprotection after bone marrow stromal cell transplantation in spinal cord injury

Introduction

Recently, cell-based therapy has gained significant attention for the treatment of central nervous system diseases. Although bone marrow stromal cells (BMSCs) are considered to have good engraftment potential, challenges due to in vitro culturing, such as a decline in their functional potency, have been reported. Here, we investigated the efficacy of rat BMSCs (rBMSCs) cultured under simulated microgravity conditions, for transplantation into a rat model of spinal cord injury (SCI).

Methods

rBMSCs were cultured under two different conditions: standard gravity (1G) and simulated microgravity attained by using the 3D-clinostat. After 7 days of culture, the rBMSCs were analyzed morphologically, with RT-PCR and immunostaining, and were used for grafting. Adult rats were used for constructing SCI models by using a weight-dropping method and were grouped into three experimental groups for comparison. rBMSCs cultured under 1 g and simulated microgravity were transplanted intravenously immediately after SCI. We evaluated the hindlimb functional improvement for 3 weeks. Tissue repair after SCI was examined by calculating the cavity area ratio and immunohistochemistry.

Results

rBMSCs cultured under simulated microgravity expressed Oct-4 and CXCR4, in contrast to those cultured under 1 g conditions. Therefore, rBMSCs cultured under simulated microgravity were considered to be in an undifferentiated state and thus to possess high migration ability. After transplantation, grafted rBMSCs cultured under microgravity exhibited greater survival at the periphery of the lesion, and the motor functions of the rats that received these grafts improved significantly compared with the rats that received rBMSCs cultured in 1 g. In addition, rBMSCs cultured under microgravity were thought to have greater trophic effects on reestablishment and survival of host spinal neural tissues because cavity formations were reduced, and apoptosis-inhibiting factor expression was high at the periphery of the SCI lesion.

Conclusions

Here we show that transplantation of rBMSCs cultured under simulated microgravity facilitates functional recovery from SCI rather than those cultured under 1 g conditions.

Labeling of olfactory ensheathing glial cells with fluorescent tracers for neurotransplantation

Development of cell-based treatment strategies for repair of the injured nervous system requires cell tracing techniques to follow the fate of transplanted cells and their interaction with the host tissue. The present study investigates the efficacy of fluorescent cell tracers Fast Blue, PKH26, DiO and CMFDA for long-term labeling of olfactory ensheathing glial cells (OEC) in culture and following transplantation into the rat spinal cord. All tested dyes produced very efficient initial labeling of p75-positive OEC in culture. The number of Fast Blue-positive cells remained largely unchanged during the first 4 weeks but only about 21% of the cells retained tracer 6 weeks after labeling. In contrast, the number of cells labeled with PKH26 and DiO was reduced to 51-55% after 2 weeks in culture and reached 8-12% after 4-6 weeks. CMFDA had completely disappeared from the cells 2 weeks after labeling. AlamarBlue assay showed that among four tested tracers only CMFDA reduced proliferation rate of the OEC. After transplantation into spinal cord, Fast Blue-labeled OEC survived for at least 8 weeks but demonstrated very limited migration from the injection sites. Additional immunostaining with glial and neuronal markers revealed signs of dye leakage from the transplanted cells resulted in weak labeling of microglia and spinal neurons. The results show that Fast Blue is an efficient cell marker for cultured OEC. However, transfer of the dye from the transplanted cells to the host tissue should be considered and correctly interpreted.

Human umbilical cord blood-derived mesenchymal stem cells do not differentiate into neural cell types or integrate into the retina after intravitreal grafting in neonatal rats

This study investigated the ability of mesenchymal stem cells (MSCs) derived from full-term human umbilical cord blood to survive, integrate and differentiate after intravitreal grafting to the degenerating neonatal rat retina following intracranial optic tract lesion. MSCs survived for 1 week in the absence of immunosuppression. When host animals were treated with cyclosporin A and dexamethasone to suppress inflammatory and immune responses, donor cells survived for at least 3 weeks, and were able to spread and cover the entire vitreal surface of the host retina. However, MSCs did not significantly integrate into or migrate through the retina. They also maintained their human antigenicity, and no indication of neural differentiation was observed in retinas where retinal ganglion cells either underwent severe degeneration or were lost. These results have provided the first in vivo evidence that MSCs derived from human umbilical cord blood can survive for a significant period of time when the host rat response is suppressed even for a short period. These results, together with the observation of a lack of neuronal differentiation and integration of MSCs after intravitreal grafting, has raised an important question as to the potential use of MSCs for neural repair through the replacement of lost neurons in the mammalian retina and central nervous system.

Efficient in vitro labeling rabbit neural stem cell with paramagnetic Gd-DTPA and fluorescent substance

OBJECTIVES

The aim of this study is to label rabbit neural stem cells (NSCs) by using standard contrast agents (Gd-DTPA) in combination with PKH26 and in vitro track them with MR imaging.

MATERIALS AND METHODS

NSCs from prenatal brains of rabbits were cultured and propagated. Intracellular uptake of Gd-DTPA was achieved by using a non-liposomal lipid transfection reagent (Effectene) as the transfection agent. After labeling with Gd-DTPA, cells were incubated with cellular membrane fluorescent dye PKH26. The labeling effectiveness and the longevity of Gd-DTPA maintenance were measured on a 1.5T MR scanner. The influence of labeling on the cellular biological behaviors was assessed by cellular viability, proliferation and differentiation assessment.

RESULTS

The labeling efficiency of Gd-DTPA was up to 90%. The signal intensity on T1-weighted imaging and T1 values of labeled cells were significantly higher than those of unlabeled cells (P<0.05). The minimal number of detectable cells for T1-weighted imaging was 5×10(3). Cellular uptake of Gd-DTPA was maintained until 15 days after initially labeling. There was no significant difference in the cellular viability and proliferation between the labeled and unlabeled NSCs (P>0.05). Normal glial and neuronal differentiation remained in labeled NSCs like unlabeled NSCs.

CONCLUSION

Highly efficient labeling NSCs with Gd-DTPA could be achieved by using Effectene. This method of labeling NSCs allows for tracking cells with MR imaging, and without alterations of cellular biological behaviors.

Primate adult brain cell autotransplantation, a pilot study in asymptomatic MPTP-treated monkeys

Autologous brain cell transplantation might be useful for repairing lesions and restoring function of the central nervous system. We have demonstrated that adult monkey brain cells, obtained from cortical biopsy and kept in culture for a few weeks, exhibit neural progenitor characteristics that make them useful for brain repair. Following MPTP treatment, primates were dopamine depleted but asymptomatic. Autologous cultured cells were reimplanted into the right caudate nucleus of the donor monkey. Four months after reimplantation, histological analysis by stereology and TH immunolabeling showed that the reimplanted cells successfully survived, bilaterally migrated in the whole striatum, and seemed to have a neuroprotection effect over time. These results may add a new strategy to the field of brain neuroprotection or regeneration and could possibly lead to future clinical applications.

Orthotopic transplantation of immortalized mesencephalic progenitors (CSM14.1 cells) into the substantia nigra of hemiparkinsonian rats induces neuronal differentiation and motoric improvement

Neural progenitor cell grafting is a promising therapeutic option in the treatment of Parkinson's disease. In previous experiments we grafted temperature-sensitive immortalized CSM14.1 cells, derived from the ventral mesencephalon of E14-rats, bilaterally in the caudate putamen of adult hemiparkinsonian rats. In these studies we were not able to demonstrate either a therapeutic improvement or neuronal differentiation of transplanted cells. Here we examined whether CSM14.1 cells grafted bilaterally orthotopically in the substantia nigra of hemiparkinsonian rats have the potential to differentiate into dopaminergic neurons. Adult male rats received 6-hydroxydopamine into the right medial forebrain bundle, and successful lesions were evaluated with apomorphine-induced rotations 12 days after surgery. Two weeks after a successful lesion the animals received bilateral intranigral grafts consisting of either about 50 000 PKH26-labelled undifferentiated CSM14.1 cells (n = 16) or a sham-graft (n = 9). Rotations were evaluated 3, 6, 9 and 12 weeks post-grafting. Animals were finally perfused with 4% paraformaldehyde. Cryoprotected brain slices were prepared for immunohistochemistry using the freeze-thaw technique to preserve PKH26-labelling. Slices were immunostained against neuronal epitopes (NeuN, tyrosine hydroxylase) or glial fibrillary acidic protein. The CSM14.1-cell grafts significantly reduced the apomorphine-induced rotations 12 weeks post-grafting compared to the sham-grafts (P < 0.05). There was an extensive mediolateral migration (400-700 microm) of the PKH26-labelled cells within the host substantia nigra. Colocalization with NeuN or glial fibrillary acidic protein in transplanted cells was confirmed with confocal microscopy. No tyrosine hydroxylase-immunoreactive grafted cells were detectable. The therapeutic effect of the CSM14.1 cells could be explained either by their glial cell-derived neurotrophic factor-expression or their neural differentiation with positive effects on the basal ganglia neuronal networks.

Transplantation of immortalized mesencephalic progenitors (CSM14.1 cells) into the neonatal parkinsonian rat caudate putamen

The present study analyzed whether grafts of the mesencephalic progenitor cell line CSM14.1 into the neonatal rat caudate putamen (CPu) differentiate into neurons and whether this is accompanied by a functional improvement in 6-hydroxydopamine (6-OHDA)-lesioned animals. As in previous studies, a neuronal differentiation of CSM14.1 cells transplanted into the CPu of adult animals could not be observed, so we here used neonatal rats, because graft location and host age seemingly are crucial parameters for neural transplant differentiation and integration. Rats bilaterally lesioned at postnatal day 1 by intraventricular 6-OHDA-injections 2 days later received 100,000 CSM14.1 cells prelabelled with the fluorescent dye PKH26 into the right CPu. Five weeks after grafting, the cylinder test was performed, and the data compared with data from age-matched intact controls and bilaterally lesioned-only animals. Brain slices immunostained for tyrosine hydroxylase (TH) were quantified by optical densitometry. We observed a significant preference of left forelimb use exclusively in transplanted animals. In these rats, TH-containing perikarya were found in the grafted CPu, presumedly leading to the significant increase of TH-immunoreactive fibers in this region. Moreover, confocal laser microscopy revealed a differentiation of transplanted PKH26-labelled CSM14.1 cells into neuronal nuclei antigen or TH-immunoreactive cells. Thus, CSM14.1 cells differentiate into TH-containing neurons, which most probably contribute to the preferred forelimb use, indicating a functional integration of CSM14.1 cells into the host basal ganglia loops during early postnatal development. These findings that are in contrast to observations in adult rats suggest instructive cues for neuronal differentiation and integration given by the neonatal microenvironment.

Generation of bone marrow-derived neural cells in serum-free monolayer culture

Bone marrow-derived cells (BMCs) are reported to trans-differentiate into neural lineages, and are expected to offer a valuable resource for treating severe diseases of the central nervous system. BMCs that show neural differentiation may differ morphologically from typical marrow stromal cells. The present study aimed to obtain efficient generation of cells with neural features from bone marrow. Serum-free culture was applied to BMCs to prevent the growth of differentiated cells. Using basic fibroblast growth factor and extracellular matrix, rodent BMCs capable of proliferation and neural differentiation expanded in monolayer form. Cultured cells were small, round or spindle-shaped, and expressed nestin. Under neural differentiation conditions, cells developed long, thin cellular processes with branches, and expressed neuronal and glial phenotypes. Intracerebrally transplanted BMCs survived and migrated into the subcortex of syngenic animals.

Cultured human and rat tooth papilla cells induce hair follicle regeneration and fiber growth

The mesenchymal-epithelial interactions that characterize the early stages of tooth and hair follicle morphogenesis share certain similarities, and there is increasing evidence that mesenchymal cells derived from both mature structures retain interactive and stem cell-like properties. This study aimed to gauge the cross-appendage inductive capabilities of cultured tooth dental papilla (or pulp) cells from different species and ages of donor. Adult human and juvenile rat tooth papilla cells were implanted into surgically inactivated hair follicles within two different microenvironments. The human cells interacted with follicle epithelium to regenerate new end bulbs and create multiple differentiated hair fibers. Rodent tooth dental cells also induced new epithelial matrix structures and stimulated de novo hair formation. However, in many instances they also elicited mineralization and bone formation, a phenomenon that appeared to relate to their donor's age; the type of tooth of origin; and the host environment. Taken together, this study reveals that cultured dental papilla cells from postnatal mammals (adult, juvenile, and newborn) retain inductive molecular signals that must be common to both hair and teeth follicles. It highlights the stem cell-like qualities and morphogenetic abilities of tooth and hair follicle cells from mature humans, and their capacity for cross-appendage and interspecies communication and interaction. Besides the developmental implications, the present findings have relevance for stem cell biology, hair growth, tissue repair, and other biotechnologies. Moreover, the critical importance of considering the local microenvironment in which different cells/tissues are naturally or experimentally engineered is firmly demonstrated.

Adrenomedullin enhances therapeutic potency of mesenchymal stem cells after experimental stroke in rats

BACKGROUND AND PURPOSE

Adrenomedullin (AM) induces angiogenesis and inhibits cell apoptosis through the phosphatidylinositol 3-kinase/Akt pathway. Transplantation of mesenchymal stem cells (MSCs) has been shown to improve neurological deficits after stroke in rats. We investigated whether AM enhances the therapeutic potency of MSC transplantation.

METHODS

Male Lewis rats (n=100) were subjected to 2-hour middle cerebral artery occlusion. Immediately after reperfusion, rats were assigned randomly to receive intravenous transplantation of MSCs plus subcutaneous infusion of AM for 7 days (MSC+AM group), AM infusion alone (AM group), MSC transplantation alone (MSC group), or vehicle infusion (control group). Neurological and immunohistological assessments were performed to examine the effects of these treatments.

RESULTS

Some engrafted MSCs were positive for neuronal and endothelial cell markers, although the number of differentiated MSCs did not differ significantly between the MSC and MSC+AM groups. The neurological score significantly improved in the MSC, AM, and MSC+AM groups compared with the control group. Importantly, improvement in the MSC+AM group was significantly greater than that in the MSC and AM groups. There was marked induction of angiogenesis in the ischemic penumbra in the MSC+AM group, followed by the AM, MSC, and control groups. AM infusion significantly inhibited apoptosis of transplanted MSCs. As a result, the number of engrafted MSCs in the MSC+AM group was significantly higher than that in the MSC group.

CONCLUSIONS

AM enhanced the therapeutic potency of MSCs, including neurological improvement, possibly through inhibition of MSC apoptosis and induction of angiogenesis.

Intravoxel distribution of DWI decay rates reveals C6 glioma invasion in rat brain

The hypothesis was tested that the intravoxel distribution of water diffusion rates, as measured with a stretched-exponential model of diffusion-weighted imaging (DWI), is a marker of brain tumor invasion. Eight rats underwent intracerebral inoculation of C6 glioma cells. In three rats, cells were labeled with a fluorescent dye for microscopy. One rat was inoculated with a saline solution, and five more rats were imaged without inoculation as controls. Five healthy uninoculated rats were also imaged. DWI was performed 14-15 days after inoculation, with diffusion-weighting factor b = 500 to 6500 sec/mm2, and the resulting signal attenuation was fitted with the stretched-exponential model. The heterogeneity index values were significantly lower (P < 0.05) in the peritumor ROI than in normal gray matter and significantly higher than in normal white matter. The distributed diffusion coefficient values were significantly lower than in normal white matter or normal gray matter. Fluorescence microscopy confirmed the presence of tumors in the peritumor region that could be histologically distinguished from the main tumor mass. There was no change in proton density or T2-weighted images in the peritumor region, making vasogenic edema unlikely as a source of contrast. It is therefore thought that the heterogeneity parameter alpha is a marker of brain tumor invasion.

Quinolinic acid lesions of the caudate putamen in the rat lead to a local increase of ciliary neurotrophic factor

When applied prior to excitotoxic lesions, ciliary neurotrophic factor (CNTF) has been shown to be neuroprotective. However, data concerning the endogenous CNTF content of the intact rat striatum are rare and have not until now been available for the quinolinic acid (QA)-lesioned striatum. Therefore, we investigated the CNTF content in the QA-lesioned rat striatum for at least 1 month using immunohistochemistry and Western blot analysis. In lesioned striata a neuronal loss was observed by Nissl staining and by a reduction of NeuN-immunoreactive cells, whereas increased glial fibrillary acidic protein immunoreactivity showed a gliotic reaction. With CNTF immunohistochemistry we found that in the QA-lesioned striatum CNTF was increased over time, whereas it was not detectable in intact and sham-lesioned striata. CNTF-immunoreactive cells had the morphology of protoplasmatic astrocytes. Furthermore, quantitative Western blotting demonstrated that the content of CNTF protein from striatal lysates containing 1 mg of whole protein 1 month after QA lesioning (2.76 +/- 1.71 ng) was significantly increased (P < 0.05, U-test) compared with sham-lesioned hemispheres (0.68 +/- 0.25 ng) and intact controls (0.55 +/- 0.25 ng). We conclude that CNTF content is correlated with glial scar formation and suggest that our results may be of relevance to cell grafting strategies for the treatment of Huntington's disease.

Pharmacological Characteristics of Rotational Behavior in Hemiparkinsonian Rats Transplanted With Mouse Embryonic Stem Cell-Derived Neurons

Embryonic stem (ES) cells have many of the characteristics of an optimal cell source for cell-replacement therapy. Although the usefulness of the in vitro generation of dopamine (DA)-neural precursors from ES cells has been widely discussed, functional recovery in animal models of Parkinson's disease is not fully understood. In 6-hydroxydopamine-lesioned rats, apomorphine markedly induced contralateral rotation. Apomorphine-induced rotation was significantly reduced by transplantation of neuron-like cells that had differentiated from mouse ES cells using nicotinamide, but not L-lysine. In addition, methamphetamine-induced ipsilateral rotation was significantly reduced. On the other hand, picrotoxin did not inhibit apomorphine-induced rotational asymmetry. Fluoxetine alone and fenfluramine alone induced slight contralateral rotation and rotation in both directions, respectively, and these effects were similar in transplanted rats. Although immunoreactivity for tyrosine hydroxylase (TH) was almost completely lost in the ipsilateral striatum in hemiparkinsonian rats, TH immunoreactivity was detected in transplanted cells and sprouting fibers. In contrast, immunoreactivities for gamma-aminobutyric acid (GABA) and serotonin (5-HT) neurons were not changed. These results suggest that improvement of rotational behavior may be induced predominantly by transplantation of nicotinamide-treated ES cell-derived DA neurons, rather than by changes in the activities of GABA or 5-HT neural systems, in hemiparkinsonian rats.

Intracerebroventricular Injection of Microglia Protects Against Focal Brain Ischemia

Microglia are macrophage-like phagocytic cells in the brain parenchyma. However, microglial function after neurodegeneration is not fully understood. In this study, occlusion of the middle cerebral artery (MCA) and reperfusion caused massive neuronal loss in the rat cerebral cortex and striatum after 3 days. When exogenous microglia were microinjected into the intracerebroventricle during MCA occlusion, neurodegenerative areas significantly decreased. At that time, migrated microglia were detected in the ischemic lesion. These results suggest that exogenous microglia can migrate into brain parenchyma and then protect against neurodegeneration induced by MCA occlusion and reperfusion.

Germ cell transplantation in goats

Transplantation of spermatogonial stem cells provides a unique approach for the study of spermatogenesis and manipulation of the male germ line. This technique may also offer an alternative to the currently inefficient methods of producing transgenic domestic animals. We have recently established the technique of spermatogonial transplantation, originally developed in laboratory rodents, in pigs, and this study was aimed to extend the technique to the goat. Isolated donor testis cells were infused into the seminiferous tubules of anesthetized recipient goats through an ultrasonographically-guided catheter inserted into the rete testis. Donor cells were obtained by enzymatic digestion of freshly collected testes from immature goats (either from the recipients' contralateral testis or from unrelated donors). Prior to transplantation, testis cells were labeled with a fluorescent marker to allow identification after transplantation. Recipient testes were examined for the presence and localization of labeled donor cells at 3-week intervals up to 12 weeks after transplantation. Labeled donor cells were found in the seminiferous tubules of all testes, comprising 10-35% of the examined tubules. Histological examination of the recipient testes did not reveal evident tissue damage, except for limited fibrotic changes at the site of needle insertion. Likewise there were no detectable local or systemic signs of immunologic reactions to the transplantations. These results indicate that germ cell transplantation is technically feasible in immature male goats and that donor-derived cells are retained in the recipient testis for at least three months and through puberty. This study represents the first report of germ cell transplantation in goats.

Germ cell transplantation in goats

Transplantation of spermatogonial stem cells provides a unique approach for the study of spermatogenesis and manipulation of the male germ line. This technique may also offer an alternative to the currently inefficient methods of producing transgenic domestic animals. We have recently established the technique of spermatogonial transplantation, originally developed in laboratory rodents, in pigs, and this study was aimed to extend the technique to the goat. Isolated donor testis cells were infused into the seminiferous tubules of anesthetized recipient goats through an ultrasonographically-guided catheter inserted into the rete testis. Donor cells were obtained by enzymatic digestion of freshly collected testes from immature goats (either from the recipients' contralateral testis or from unrelated donors). Prior to transplantation, testis cells were labeled with a fluorescent marker to allow identification after transplantation. Recipient testes were examined for the presence and localization of labeled donor cells at 3-week intervals up to 12 weeks after transplantation. Labeled donor cells were found in the seminiferous tubules of all testes, comprising 10-35% of the examined tubules. Histological examination of the recipient testes did not reveal evident tissue damage, except for limited fibrotic changes at the site of needle insertion. Likewise there were no detectable local or systemic signs of immunologic reactions to the transplantations. These results indicate that germ cell transplantation is technically feasible in immature male goats and that donor-derived cells are retained in the recipient testis for at least three months and through puberty. This study represents the first report of germ cell transplantation in goats.

Transplantation of neural stem cells in a rat model of stroke: assessment of short-term graft survival and acute host immunological response

The use of progenitors and stem cells for neural grafting is promising, as these not only have the potential to be maintained in vitro until use, but may also prove less likely to evoke an immunogenic response in the host, when compared to primary (fetal) grafts. We investigated whether the short-term survival of a grafted conditionally immortalised murine neuroepithelial stem cell line (MHP36) (2 weeks post-implantation, 4 weeks post-ischaemia) is influenced by: (i) immunosuppression (cyclosporin A (CSA) vs. no CSA), (ii) the local (intact vs. lesioned hemisphere), or (iii) global (lesioned vs. sham) brain environment. MHP36 cells were transplanted ipsi- and contralateral to the lesion in rats with middle cerebral artery occlusion (MCAo) or sham controls. Animals were either administered CSA or received no immunosuppressive treatment. A proliferation assay of lymphocytes dissociated from cervical lymph nodes, grading of the survival of the grafted cells, and histological evaluation of the immune response revealed no significant difference between animals treated with or without CSA. There was no difference in survival or immunological response to cells grafted ipsi- or contralateral to the lesion. Although a local upregulation of immunological markers (MHC class I, MHC class II, CD45, CD11b) was detected around the injection site and the ischaemic lesion, these were not specifically upregulated in response to transplanted cells. These results provide evidence for the low immunogenic properties of MHP36 cells during the initial period following implantation, known to be associated with an acute host immune response and ensuing graft rejection.

Effects of implantation site of stem cell grafts on behavioral recovery from stroke damage

BACKGROUND AND PURPOSE

Findings that MHP36 stem cells grafted into intact parenchyma contralateral to the lesion induced by middle cerebral artery occlusion promoted recovery from stroke deficits led us to investigate whether implantation site of stem cells affects the functional efficacy of MHP36 grafts.

METHODS

MHP36 cells (200 000/8 microL) were implanted in the left (n=8) or right (n=9) parenchyma or infused into the right ventricle (intraventricular; n=7) 2 to 3 weeks after stroke induced by 60 minutes of intraluminal right middle cerebral artery occlusion. Additionally, intact (n=11) and stroke (n=7) control groups were tested for 14 weeks in bilateral asymmetry, rotation bias, and spatial learning tasks before histological investigation of cell distribution and differentiation.

RESULTS

Rats with left and right parenchymal grafts showed reduced bilateral asymmetry but no improvement in spatial learning. Conversely, spatial learning improved in rats with intraventricular grafts, but marked asymmetry persisted. No grafted group showed reduced amphetamine-induced rotation bias or reduced lesion volume relative to stroke controls. In all grafted groups, cells occupied both sides of the brain. A third of cells grafted in the striatum crossed the midline to occupy homologous regions in intact and lesioned hemispheres and differentiated into site-appropriate phenotypes.

CONCLUSIONS

After stroke, both the intact and lesioned hemispheres attract grafted stem cells, suggesting repair processes that utilize cells both for local repair and to augment plastic changes in contralateral motor pathways. However, differential effects of parenchymal and intraventricular grafts suggest that different mechanisms are implicated in recovery from cognitive and sensorimotor deficits induced by stroke.

Germ cell transplantation in pigs

Spermatogonial stem cells form the foundation of spermatogenesis, and their transplantation provides a unique opportunity to study spermatogenesis and may offer an alternative approach for animal transgenesis. This study was designed to extend the technique of spermatogonial transplantation to an economically important, large-animal model. Isolated immature pig testes were used to develop the intratesticular injection technique. Best results of intratubular germ cell transfer were obtained when a catheter was inserted into the rete testis under ultrasound guidance. The presence of infused dye or labeled cells was confirmed in the seminiferous tubules from 70 of 89 injected isolated testes. Infusion of 3-6 ml of dye solution or cell suspension could fill the rete and up to 50% of seminiferous tubules. The technique was subsequently applied in vivo. Donor cells included testis cells from 1- or 10-wk-old boars (from the recipients' contralateral testis or unrelated donors) and those from mice carrying a marker gene. Porcine testis cells were labeled with a fluorescent marker before transplantation. Testes were examined for the presence and localization of labeled donor cells immediately after transplantation or every week for 4 wk. Labeled porcine donor cells were found in numerous seminiferous tubules from 10 of 11 testes receiving pig cells. These results indicate that germ cell transplantation is feasible in immature pigs, and that porcine transplanted cells are retained in the recipient testis for at least 1 mo. This study represents a first step toward successful spermatogonial transplantation in a farm animal species.