Development and characterization of islet-derived mesenchymal stem cells from clinical grade neonatal porcine cryopreserved islets.

BACKGROUND: Porcine tissues display a great potential as donor tissues in xenotransplantation, including cell therapy. Cryopreserving clinical grade porcine tissue and using it as a source for establishing therapeutic cells should be advantageous for transportation and scheduled manufacturing of MSCs. Of note, we previously performed encapsulated porcine islet transplantation for the treatment of unstable type 1 diabetes mellitus in the clinical setting. It has been reported that co-transplantation of islets and Mesenchymal stem cells (MSCs) enhanced efficacy. We assume that co-transplantation of porcine islets and porcine islet-derived MSCs could improve the efficacy of clinical islet xenotransplantation. METHODS: MSCs were established from fresh and cryopreserved non-clinical grade neonatal porcine islets and bone marrow (termed non-clinical grade npISLET-MSCs and npBM-MSCs, respectively), as well as from cryopreserved clinical grade neonatal porcine islets (termed clinical grade npISLET-MSCs). Subsequently, the cell proliferation rate and diameter, surface marker expression, adipogenesis, osteogenesis, and colony-forming efficiency of the MSCs were assessed. RESULTS: Cell proliferation rate and diameter did not differ between clinical grade and non-clinical grade npISLET-MSCs. However, non-clinical grade npBM-MSCs were significantly shorter and smaller than both npISLET-MSCs (p < 0.05). MSC markers (CD29, CD44, and CD90) were strongly expressed in clinical grade npISLET-MSCs and non-clinical grade npISLET-MSCs and npBM-MSCs. The expression of MSC-negative markers CD31, CD34, and SLA-DR was low in all MSCs. Clinical grade npISLET-MSCs derived from adipose and osteoid tissues were positive for Oil Red and alkaline phosphatase staining. The results of colony-forming assay were not significantly different between clinical grade npISLET-MSCs and non-clinical grade npBM-MSCs. CONCLUSION: The method described herein was successful in of developing clinical grade npISLET-MSCs from cryopreserved islets. Cryopreserved clinical grade porcine islets could be an excellent stable source of MSCs for cell therapy.

Ascorbic acid enhances the cold preservation period of human adipose tissue-derived mesenchymal stromal cells.

Introduction: We previously developed 3% trehalose-added lactated Ringer's solution (LR-3T) and 3% trehalose- and 5% dextran-40-added lactated Ringer's solution (LR-3T-5D), which can be used to preserve adipose-derived mesenchymal stem cells (hADSCs) for 24 h at 5 and 25 °C. However, it is necessary to further extend the storage duration of cells to expand transportation zones and ensure time for quality control testing of final cell products. Therefore, we attempted to prolong the preservation duration of hADSCs by adding supplements to LR-3T-5D. We focused on ascorbic acid as an antioxidant because it is widely clinically as a nutrient. Methods: We added the antioxidant ascorbic acid to LR-3T-5D and evaluated the viability, colony formation rate, proliferative capacity, and surface markers of hADSCs before and after preservation at 5 °C. Results: Analysis of the concentration of ascorbic acid added to LR-3T-5D indicated that 1000 mg/L was the optimal concentration for maintaining the viability of hADSCs after 72 h of cold preservation. No changes were observed in the expression of specific cell surface markers or in the potential of hADSCs to differentiate into adipocytes, osteoblasts, or chondrocytes before and after cold preservation. Discussion: These results suggest that cold preservation of hADSCs in LR-3T-5D supplemented with ascorbic acid helps maintain the quality of cells for use in cell therapy.

Relationship between oxygen partial pressure and inhibition of cell aggregation of human adipose tissue-derived mesenchymal stem cells stored in cell preservation solutions.

Introduction: This study investigated the storage conditions under which cell aggregation occurs and the conditions that inhibit cell aggregation when human adipose tissue-derived mesenchymal stem cells (hADSCs) are stored in lactated Ringer's solution (LR) supplemented with 3% trehalose and 5% dextran 40 (LR-3T-5D). Methods: We first examined the effects of storage temperature and time on the aggregation and viability of hADSCs stored in LR and LR-3T-5D. The cells were stored at 5 °C or 25 °C for various times up to 24 h. We then evaluated the effects of storage volume (250-2,000 µL), cell density (2.5-20 × 105 cells/mL), and nitrogen gas replacement on aggregation, oxygen partial pressure (pO2), and viability of hADSCs stored for 24 h at 25 °C in LR-3T-5D. Results: When stored in LR-3T-5D, viability did not change under either condition compared with pre-storage, but the cell aggregation rate increased significantly with storage at 25 °C for 24 h (p<0.001). In LR, the aggregation rate did not change under either condition, but cell viability decreased significantly after 24 h at both 5 °C and 25 °C (p < 0.05). The cell aggregation rates and pO2 tended to decrease with increasing solution volume and cell density. Nitrogen gas replacement significantly decreased the cell aggregation rate and pO2 (p < 0.05). However, there were no differences in viability among cells stored under conditions of different storage volumes, densities, and nitrogen gas replacement. Conclusions: Aggregation of cells after storage at 25 °C in LR-3T-5D may be suppressed by increasing the storage volume and cell density as well as by incorporating nitrogen replacement, which lowers the pO2 in the solution.

Dimethyl sulfoxide-free cryopreservation solution containing trehalose, dextran 40, and propylene glycol for therapy with human adipose tissue-derived mesenchymal stromal cells.

We evaluated a dimethyl sulfoxide (Me2SO)-free cryopreservation solution to freeze human adipose-derived mesenchymal stromal cells (hADSCs). In the first experiment, we compared the combined effects of 3% trehalose (3 T) and 5% dextran (5D) in lactated Ringer's solution (LR) as a cryopreservation base solution containing 10% propylene glycol (PG). The cell viability of hADSCs immediately after thawing was significantly higher (p < 0.05) in LR supplemented with 3 T (LR-3 T) and with 3 T and 5D (LR-3 T-5D) than in LR. In the second experiment, we compared the cell characteristics of hADSCs freeze-thawed in LR-3 T-5D containing either 10% Me2SO or 10% PG. The cell viability, annexin V-positive ratio, colony-forming capacity, cell proliferation, cell surface antigen positivity, adipogenic differentiation, osteogenic differentiation, and genetic response to cytokine stimulation of hADSCs immediately after thawing were similar between the LR-3 T-5D containing 10% Me2SO and 10% PG. In the third experiment, we examined various concentrations of PG on the cell proliferative capacity of freeze-thawed hADSCs. The cell proliferative capacity of hADSCs frozen with LR-3 T-5D containing 2.5% to 5% PG was significantly higher (p < 0.05) than LR-3 T-5D containing 10% PG. Furthermore, the cell proliferative capacity of hADSCs frozen with LR-3 T-5D containing 4% PG was similar to that of fresh hADSCs. These results indicate that the combination of 3 T-5D in an LR solution as a basic solution is effective for post-thaw cell viability, and that the optimal concentration of PG to maintain the cell characteristics of hADSCs frozen with LR-3 T-5D is 2.5% to 5%, which is promising for cell therapy applications.

Xenotransplantation of neonatal porcine bone marrow-derived mesenchymal stem cells improves diabetic wound healing by promoting angiogenesis and lymphangiogenesis.

BACKGROUND: Some clinical trials have shown the usefulness of stem cell therapy for diabetic foot ulcers. However, the donor supply is limited, and the process is time consuming and expensive. This study assessed the therapeutic effects of neonatal porcine bone marrow-derived mesenchymal stem cell (npBM-MSC) xenotransplantation using diabetic wound model mice. METHODS: All layers of back skin were removed from streptozotocin-induced diabetic mice. In the npBM-MSCs group, npBM-MSCs were transplanted to the wound, and syngeneic mouse bone marrow-derived mesenchymal stem cells (mBM-MSCs) were transplanted to the wound in the mBM-MSCs group. The control group comprised diabetic mice that did not receive cellular therapy. The therapeutic effects of the transplantation were evaluated according to the rate of wound closure and the promotion of neovascularization in the wound. RESULTS: The wound closure rate was significantly improved in the npBM-MSCs group compared with the control group (p < .001 at postoperative day [POD] 4 and p < .01 at POD 7) and mBM-MSCs groups (p < .05 at POD 4). Prominent promotion of both angiogenesis and lymphangiogenesis was observed in the npBM-MSCs group. Furthermore, the expression of murine Prox1 and both porcine and murine Vegfs and Tgfb1 in the wounds was enhanced until POD 4 by npBM-MSCs transplantation. The amounts of vascular endothelial growth factor (VEGF) A, VEGFC, and transforming growth factor ß1 secreted from npBM-MSCs were higher than those from mBM-MSCs (p < .05). CONCLUSION: Xenotransplantation of npBM-MSCs improved diabetic wound healing by promoting both angiogenesis and lymphangiogenesis.

Development and characterization of Gal KO porcine bone marrow-derived mesenchymal stem cells.

BACKGROUND: We demonstrated that neonatal porcine bone marrow-derived mesenchymal stem cell (npBM-MSCs) could improve a critical ischemic limb disease in rat model more efficiently compared with human MSCs. However, since porcine MSC presents galactosyl-alpha 1,3-galactose antigen (Gal antigen), MSC could be eliminated by the xenogeneic rejection. Recently, we established Gal knockout (KO) pigs by a technique of the electroporation of the CRISPR/Cas9 system into vitro-fertilized zygotes. In this study, we hypothesized that MSC from the established Gal KO pigs could further improve the efficacy. Before examining the hypothesis, in this study, we have established and characterized bone marrow-derived MSC from the Gal KO adult pigs (apBM-MSCs). METHODS: Mononuclear cells (MNCs) were isolated from bone marrow cells of both Gal KO adult pigs and wild-type (WT) adult pigs. MNCs were further manipulated to create Gal KO apBM-MSCs and WT apBM-MSCs. Both MSCs were assessed by their surface markers, the capability of differentiation into adipocytes, osteocytes and chondrocytes, grow speed and colony-forming assay. To assess the efficacy of Gal KO apBM-MSCs, angiogenesis-related genes and immunosuppression-related genes were assessed by cytokine stimulation. RESULTS: Gal KO apBM-MSC showed no Gal antigen on their cell surfaces. Both Gal KO apBM-MSCs and WT apBM-MSCs, presented little or no negative surface markers of MSCs, while they presented positive surface markers of MSCs. Furthermore, Gal KO apBM-MSCs were able to differentiate into adipocytes, osteocytes, and chondrocytes as well as WT apBM-MSCs. There was no difference in doubling time between Gal KO apBM-MSCs and WT apBM-MSCs. Interestingly, the colony-forming efficiency of Gal KO apBM-MSCs was about half that of WT apBM-MSC. However, angiogenesis and immunosuppression-related genes were equally upregulated in both Gal KO apBM-MSCs and WT apBM-MSCs by cytokine stimulation. CONCLUSION: We created and characterized Gal KO apBM-MSCs which showed similar characteristics and cytokine-induced gene upregulation to the WT apBM-MSCs.

Xenotransplantation of neonatal porcine bone marrow-derived mesenchymal stem cells improves murine hind limb ischemia through lymphangiogenesis and angiogenesis.

BACKGROUND: The clinical utility of stem cell therapy for peripheral artery disease has not been fully discussed, and one obstacle is limited donor supplies. In this study, we attempted to rescue mouse ischemic hind limb by xenotransplantation of neonatal porcine bone marrow-derived mesenchymal stem cells (npBM-MSCs). METHODS: Neonatal porcine bone marrow-derived mesenchymal stem cells were transplanted to ischemic hind limbs of male C57BL/6J mice (npBM-MSCs group). Mice with syngeneic transplantation of mouse BM-MSCs (mBM-MSCs group) were also prepared for comparison. The angiogenic effects were evaluated by recovery of blood flow on laser Doppler imaging, histologic findings, and genetic and protein levels of angiogenic factors. RESULTS: Regarding laser Doppler assessments, blood flow in the hind limb was rapidly recovered in the npBM-MSCs group, compared with that in the mBM-MSCs group (P = .016). Compared with the mBM-MSCs group, the npBM-MSCs group had early and prominent lymphangiogenesis [P < .05 on both post-operative days (PODs) 3 and 7] but had similar angiogenesis. Regarding genomic assessments, xenotransplantation of npBM-MSCs enhanced the expressions of both porcine and murine Vegfc in the hind limbs by POD 3. Interestingly, the level of murine Vegfc expression was significantly higher in the npBM-MSCs group than in the mBM-MSCs group on PODs 3 and 7 (P < .001 for both). Furthermore, the secreted VEGFC protein level was higher from npBM-MSCs than from mBM-MSCs (P < .001). CONCLUSION: Xenotransplantation of npBM-MSCs contributed to the improvement of hind limb ischemia by both angiogenesis and lymphangiogenesis, especially promotion of the latter. npBM-MSCs may provide an alternative to autologous and allogeneic MSCs for stem cell therapy of critical limb ischemia.

Protein-free solution containing trehalose and dextran 40 for cryopreservation of human adipose tissue-derived mesenchymal stromal cells.

We tested the efficacy of lactated Ringer's solution with 3% trehalose and 5% dextran 40 (LR-3T-5D) as a vehicle solution for cryopreservation using human adipose-derived mesenchymal stromal cells (hADSCs) with dimethyl sulfoxide (Me2SO). We also tested the effect of the Me2SO concentration in the cryopreservation solution, and the effect of washing with lactated Ringer's solution with 3% trehalose (LR-3T) and replacement with LR-3T or LR-3T-5D. LR-3T-5D was more effective for cell viability, viable cell recovery ratio, annexin V-positive ratio, and colony-forming capacity as a vehicle solution for cryopreservation with 10% Me2SO than LR. The additive effects as cryoprotectants of trehalose and dextran 40 were confirmed to be dose dependent. The cell viability, cell proliferation ability, cell differentiation ability, and the ratio of cell surface positive/negative markers of hADSCs were well maintained after cryopreservation with LR-3T-5D containing 10% Me2SO in liquid nitrogen or in a -80 °C freezer. The cell viability and the proliferation curve in LR-3T-5D with 5% Me2SO were comparable to those with 10% Me2SO. LR-3T-5D was superior to LR-3T as a replacement solution in terms of viability and annexin V positivity. Our data showed that LR-3T-5D is effective as a vehicle solution for cryopreservation. Reducing Me2SO concentration to 5%, and washing and replacement with fresh LR-3T and LR-3T-5D after thawing, are feasible approaches to maintain cryopreservation efficacy.

A pair of cell preservation solutions for therapy with human adipose tissue-derived mesenchymal stromal cells.

INTRODUCTION: Stem cells for therapy are often suspended in a preservation solution, such as normal saline or lactated Ringer's solution, for a short time before intravenous infusion. However, these solutions are not necessarily ideal for maintaining cell viability and preventing the sedimentation of cells during storage and infusion. In this study, we attempted to optimize the compositions of preservation solutions, which could affect the efficacy and safety of stem cell therapy. METHODS: We determined the characteristics of a preservation solution that would optimize cell viability and the percentage of cells in the supernatant using human adipose-derived mesenchymal stromal cells (hADSCs). We compared solutions that differed by electrolytes (e.g., normal saline and Ringer's solution) and the concentrations of dextran 40 and trehalose. The effects of the solutions on hADSCs were evaluated by assessing cell surface markers, colony-forming capacity, differentiation potential, and cell concentrations in the infusion line. RESULTS: Optimized preservation solutions consisted of lactated Ringer's solution with 3% trehalose without or with 5% dextran 40 (LR-3T and LR-3T-5D, respectively). The cell viabilities after 24 h of storage at 5 °C in LR-3T and LR-3T-5D were 94.9% ± 2.4% and 97.6% ± 2.4%, respectively. The percentage of cells in the supernatant after 1 h of storage at room temperature in LR-3T-5D was 83.5% ± 7.6%. These solutions preserved the percentage of cell surface marker-positive cells, the colony-forming capacity, and the adipogenic and osteogenic differentiation ability in hADSCs for at least 24 h after preservation at 5 °C and 25 °C. DISCUSSION: We determined the optimal composition of preservation solutions for hADSCs and confirmed the effects of these solutions on cell viability and the stability of cell characteristics in vitro. Our results suggest that LR-3T and LR-3T-5D can help maintain the quality of stem cells for therapy during preservation and infusion. However, further in vivo research is needed on the efficacy and safety of the solutions in different therapeutic cell lines before clinical use.

The pharmacokinetics of porcine C-peptide after intraperitoneal injection.

BACKGROUND: Previously, we have demonstrated that there were very low C-Peptide concentrations and normal blood glucose levels when we transplanted encapsulated islets in the abdominal cavity of diabetic nude mice. In addition, the C-peptide concentration in the ascites fluid of the peritoneal cavity was 40 times higher than in the peripheral blood. In this study, we investigated the pharmacokinetics of intraperitoneal porcine C-peptide. METHODS: To assess the pharmacokinetics of porcine C-peptide, a synthesized porcine C-peptide solution was injected into the peripheral circulation through the tail vein or into the peritoneal cavity in rats at low or high doses of either 200 or 2000 pmol/kg, respectively. Arterial blood samples were collected at time intervals of 1-120 minutes after injection to calculate the terminal elimination half-life (t1/2 ) and area under the time-concentration curve (AUC0-t ). RESULTS: After intraperitoneal C-peptide injection, the highest porcine C-peptide concentration in peripheral blood was only one-fortieth compared to after intravenous injection. The AUC0-t for the intraperitoneal injection was 78% at the low dose and only 39% at the high dose compared to the intravenous injection. This finding indicates that C-peptide remains in the abdominal cavity when intraperitoneally transplanted islets release C-peptide via high glucose stimulation. CONCLUSIONS: Porcine C-peptide injected into a peritoneal cavity slowly and incompletely entered peripheral circulation, which resulted in very low concentration in peripheral blood.

Development and characterization of novel clinical grade neonatal porcine bone marrow-derived mesenchymal stem cells.

Due to recent advances in research on mesenchymal stem cells (MSCs), MSCs are expected to be used in various clinical applications. However, securing adequate cadaveric donors and safety of living donors are major issues. To solve such issues, we have examined to develop clinical grade neonatal porcine bone marrow-derived MSCs (npBM-MSCs). Clinical grade neonatal porcine bone marrow cells were collected, frozen, and sent to our laboratory by air. The npBM-MSCs were isolated from thawed bone marrow cells, then frozen. The thawed npBM-MSCs were examined for CD markers and differentiated into chondrocytes, osteocytes, and adipocytes. They were compared with human bone marrow-derived MSCs (hBM-MSCs) for growth rate and size. To assess the robustness of proliferation, we compared culture medium with or without gelatin. The npBM-MSCs expressed positive MSC markers CD29, CD44, and CD90 and were differentiated into chondrocytes, osteocytes, and adipocytes. The doubling time of npBM-MSCs was significantly shorter than that of hBM-MSCs (17.3 ± 0.8 vs 62.0 ± 19.6 hours, P < 0.01). The size of npBM-MSCs was also significantly smaller than that of hBM-MSCs (13.1 ± 0.3 vs 17.5 ± 0.4 µm, P < 0.001). The npBM-MSCs showed similar proliferation characters irrespective of with or without gelatin coating. The npBM-MSCs secreted VEGF-A, VEGF-C, and TGF-ß1. We have established npBM-MSCs which show super-rapid growth, small size, and robust proliferation profile. The np-MSCs might be able to solve the donor issues for MSC therapy.

Effects of encapsulated porcine islets on glucose and C-peptide concentrations in diabetic nude mice 6 months after intraperitoneal transplantation.

BACKGROUND: In patients with type 1 diabetes, allogeneic islet transplantation can provide normal HbA1c concentrations, but it requires immunosuppression. Transplanting encapsulated islets into the peritoneal cavity could reduce or eliminate the need for immunosuppression. One of the uncertain features of intraperitoneal islet transplantation is the difficulty of measuring C-peptide concentrations in peripheral blood, which is often used for the marker of islet function. We hypothesized that secreted C-peptide from intraperitoneally transplanted islets was mostly consumed in the peritoneal cavity, which resulted in low C-peptide concentrations in peripheral blood. METHODS: In each of two experiments, encapsulated neonatal porcine islets were intraperitoneally transplanted into four nude mice with streptozotocin-induced diabetes. Three diabetic nude mice without transplanted islets were used as diabetic controls, and three untreated healthy nude mice were used as normal controls. Islet functions were monitored for 2 months in the first experiment and 6 months in the second experiment. Encapsulated islets were retrieved after each experiment and evaluated by fluorescein diacetate/propidium iodide tests for the viability and static glucose-stimulated insulin release tests for the function. C-peptide concentrations from the blood and from the intraperitoneal cavity at 6 months were compared. RESULTS: In both experiments, diabetes was reversed in all transplanted mice, and oral glucose tolerance test showed improved profiles. In general, retrieved islets were viable and functional. However, blood porcine C-peptide concentrations were low at both 2 and 6 months, and concentrations in the ascites of peritoneal cavity were 40 times as high as those in blood. CONCLUSIONS: The peripheral blood sampling for c-peptide, though highly informative in vascularized grafts, may not be the primary tool for monitoring the health and function of encapsulated products when transplanted into intraperitoneal cavity. Our results might explain the clinical feature of the low C-peptide blood concentrations after successful intraperitoneal encapsulated islet transplantation.

Intrathecal disposition of ARTCEREB® irrigation and perfusion solution for cerebrospinal surgery in rats.

We investigated the disposition of ARTCEREB® irrigation and perfusion solution (Artcereb) during intrathecal perfusion in a lateral ventricle-cisternal perfusion model in conscious rats. In this perfusion model, the perfusion rate was set at 0.35 ml/kg/h, taking into consideration the clinical perfusion rate (500 ml/60 kg/d). The influence of Artcereb on electrolytes in cerebrospinal fluid (CSF) and blood were then investigated. After 24 h of ventriculocisternal perfusion with Artcereb using the push-pull method, output of K(+), Na(+) and Cl(-) to the cistern magna was very similar to input of these electrolytes in Artcereb infused intraventricularly. Recovery rates of K(+), Na(+) and Cl(-) after perfusion were 102%, 105% and 100% when calculated using the recovered perfusion solution. In addition, concentrations of K(+), Na(+) and Cl(-) in blood remained almost constant at near baseline levels throughout perfusion. Thus, intrathecally perfused Artcereb did not affect electrolyte balance in the CSF and blood. To confirm the dynamics of Artcereb distribution, a whole body autoradiography study was performed at 1 and 6 h after perfusion with ¹4C-inulin-added Artcereb. Radioactivity was detected in the entire CSF space of the brain, and the cribriform plate in the nasal cavity, and the cerebrospinal cavity. Radioactivity was observed in the bladder, thus suggesting that some ¹4C-inulin was transferred to the bloodstream via a physiological route, and was excreted renally.

Expression levels of drug-metabolizing enzyme, transporter, and nuclear receptor mRNAs in a novel three-dimensional culture system for human hepatocytes using micro-space plates.

We evaluated a novel three-dimensional primary culture system using micro-space plates to determine the expression levels of 61 target (drug-metabolizing enzymes, transporters, and nuclear receptors) mRNAs in human hepatocytes. We measured mRNA expression levels of many target genes in four lots of cryopreserved human hepatocyte primary cells after 120 h of culture and compared differences in mRNA expression levels between cultures using traditional plates and those using micro-space plates. In this study, we show that the mRNA levels of many experimental targets in human hepatocytes before inoculation resemble the levels inside the human liver. Furthermore, we show that the rate of change of expression levels of many target mRNAs relative to the value before inoculation of the hepatocytes into micro-space plates was relatively smaller than the rate of change in hepatocytes inoculated into traditional plates. Pharmacokinetics-related examinations using this system are possible within a time frame of 120 h. We report that this novel three-dimensional culture system reproduces mRNA expression levels that are nearer to those in the liver in vivo and is an excellent platform for maintaining mRNA expression levels of drug-metabolizing enzymes and transporters when compared to common monolayer cultures.

Pharmacological assessment of ARTCEREB irrigation and perfusion solution for cerebrospinal surgery using primary cultures of rat brain cells.

ARTCEREB irrigation and perfusion solution (Artcereb), an ethical pharmaceutical, is typically applied inside the skull and spinal cavity as artificial fluid. Artcereb is composed of glucose and electrolytes (Na+, K+, Mg2+, Ca2+, Cl-, HCO3- and P) and has a pH of 7.3. An in vitro assessment of the effects of Artcereb on cell culture of rat fetal astrocytes or rat fetal brain cells was performed in comparison with normal saline and lactated Ringer's solutions. Furthermore, the effects of Artcereb on cell culture of rat fetal brain cells were also assessed in comparison with Krebs bicarbonate solution. Cell function after exposure to Artcereb was assessed based on 3H-thymidine incorporation activity. Cell function after exposure to Artcereb and lactated Ringer's solution in primary cultures of rat fetal astrocytes remained unaffected when compared to that after exposure to normal saline. Cell function after exposure to Artcereb in a primary culture of rat brain cells remained unaffected as compared to that after exposure to normal saline and lactated Ringer's solution. However, function decreased after exposure to a modified Artcereb formulation lacking bicarbonate, thus confirming that the presence of bicarbonate is essential for the Artcereb formulation.

Secretion of albumin and induction of CYP1A2 and CYP3A4 in novel three-dimensional culture system for human hepatocytes using micro-space plate.

We evaluated a novel primary three-dimensional culture system for human hepatocytes using micro-space plates. The functional activity of human hepatocytes in primary culture was determined by measuring albumin secretion from hepatocytes to medium and measuring expression levels of albumin, CYP1A2 and CYP3A4 mRNA. Albumin secretion was higher in micro-space plates compared with traditional plates after 72 h of culture; the levels of albumin secretion from hepatocytes to medium in culture using micro-space plates after 96 h of culture were 2.7-fold higher than those in culture using traditional plates, and secretion of albumin in micro-space plate culture subsequently remained constant. Expression levels of albumin, CYP1A2 and CYP3A4 mRNA in the culture of hepatocytes were significantly higher using micro-space plates than using traditional plates. The inducibility of CYP1A2 and CYP3A4 mRNA after exposure to inducers in hepatocyte culture on micro-space plates was comparable to that in culture on traditional plates, while expression of CYP1A2 and CYP3A4 mRNA after exposure to inducers was higher on micro-space plates than on traditional plates. The present study demonstrates that a novel primary three-dimensional culture system of cryopreserved human hepatocytes using micro-space plates could be used for evaluating the induction of drug-metabolizing enzymes in humans. This in vitro method may thus be useful for screening the induction potency of new drug candidates.

[Pharmacological assessment of ARTCEREB irrigation and perfusion solution for cerebrospinal surgery based on glucose incorporation activity in primary cultures of rat brain cells].

ARTCEREB irrigation and perfusion solution (Artcereb) is typically used as an artificial fluid for applications inside the skull and spinal cavity. This in vitro study was conducted to assess the effects of Artcereb in cultures of rat fetal brain cells. Cell function following exposure to Artcereb was evaluated by measuring (3)H-deoxy-D-glucose incorporation activity. Cell function was significantly reduced in primary cultures of rat fetal brain cells at 0 h and 24 h after 1-h or 3-h exposure to normal saline as compared with Artcereb. Cell function was also significantly reduced at 24 h after 3-h exposure to lactated Ringer's solution as compared with Artcereb. Furthermore, cell function was significantly reduced at 24 h after 3-h exposure to a modified Artcereb formulation lacking either HCO(3)(-) or Mg(2+) as compared with Artcereb, while cell function was unaffected at 24 h after exposure to lactated Ringer's solution with HCO(3)(-) or normal saline with HCO(3)(-) as compared with Artcereb. These findings suggest the importance of the presence of HCO(3)(-) and Mg(2+) in the formulation of Artcereb.

Evaluation of induction potency of new drug candidates on CYP1A2 and CYP3A4 using real-time one-step RT-PCR in primary cultures of cryopreserved human hepatocytes.

SUMMARY: This study evaluates the induction potency of new drug candidates on mRNA levels of CYP1A2 and CYP3A4 in primary cultures of cryopreserved human hepatocytes. Analysis was performed by quantitative real-time RT-PCR using primers and TaqMan probes. Positive controls for CYP1A2 and CYP3A4 used beta-naphthoflavone (beta-NF) and rifampicin (Rif), respectively. In the first stage of the study, the lot showing the best induction of mRNA expression CYP1A2 and CYP3A4 from among eight lots of hepatocytes was selected. In the second stage, we evaluated the levels of CYP1A2 and CYP3A4 gene expression in hepatocytes after exposure to eight NO-1886 (ibrolipim) derivatives. A combination of real-time one-step RT-PCR and primary culture of cryopreserved human hepatocytes is suitable for evaluating of induction potency of a large number of new drug candidates.

Perfusion fluids used in neurosurgery affect cerebrospinal fluid and surrounding brain parenchyma in the rat ventriculocisternal perfusion model.

ARTCEREB, an irrigation and perfusion solution (Artcereb), is a preparation intended for the irrigation and perfusion of the cerebral ventricles, and it is therefore important to evaluate its effects on cerebrospinal fluid (CSF) and on the surrounding cerebrospinal parenchyma. To confirm the kinetics of the perfusion fluid component, we performed whole body autoradiography and examined glucose balance during ventriculocisternal perfusion with (14)C-glucose labeled Artcereb in the rat model, which simulates ventricular irrigation or ventriculocisternal perfusion in clinical neurosurgery. We also performed ventriculocisternal perfusion with Artcereb, lactated Ringer's solution, or normal saline, and observed the effect of these solutions on animal condition and on brain tissue morphology. In the kinetic study, diffusion of (14)C-glucose from the perfused Artcereb to the cerebrospinal tissue was seen on whole body autoradiography, and almost 90% of the glucose in the perfusion fluid was distributed to the cerebrospinal tissue and the systemic circulation. These data indicated that the perfusion fluid interacted actively with the CSF, surrounding parenchyma and the systemic circulation, and suggested that the formation of perfusion fluid affected CSF composition and cerebrospinal tissue functions. Animals perfused with normal saline were associated with serious symptoms including tonic convulsions and death, and exhibited neuronal death in the cerebrum. However, these severe changes were not observed in animals perfused with Artcereb or lactated Ringer's solution. We therefore propose that during neurosurgery, it is extremely important to use a physiological solution like Artcereb which closely resembles normal human CSF, in order to maintain cerebrospinal function and to alleviate postoperative adverse events.