Transplantation of osteogenically differentiated mouse iPS cells for bone repair

Induced pluripotent stem (iPS) cells are a type of undifferentiated cell that can be obtained from differentiated cells and have the pluripotent potential to differentiate into the musculoskeletal system, the myocardium, vascular endothelial cells, neurons, and hepatocytes. We therefore cultured mouse iPS cells in a DMEM containing 15% FBS, 10(-7) M dexamethasone, 10 mM β-glycerophosphate, and 50 μg/ml ascorbic acid for 3 weeks, in order to induce bone differentiation, and studied the expression of the bone differentiation markers Runx2 and osteocalcin using RT-PCR in a time-dependent manner. Osteocalcin, a bone differentiation marker in bone formation, exhibited the highest expression in the third week. In addition, the deposition of calcium nodules was observed using Alizarin red S staining. iPS cells cultured for bone differentiation were transplanted into severe combined immunodeficiency (SCID) mice, and the osteogenic potential exhibited after 4 weeks was studied. When bone differentiation-induced iPS cells were transplanted into SCID mice, bone formation was confirmed in soft X-ray images and tissue specimens. However, teratoma formation was confirmed in 20% of the transplanted models. When mouse iPS cells were treated with irradiation of 2 Gray (Gy) prior to transplantation, teratoma formation was inhibited. When mouse iPS cells treated in a likewise manner were xenotransplanted into rats, bone formation was confirmed but teratoma formation was not observed. It is believed that irradiation before transplantation is an effective way to inhibit teratoma formation.     

Docosahexaenoic acid promotes dopaminergic differentiation in induced pluripotent stem cells and inhibits teratoma formation in rats with Parkinson-like pathology

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the degeneration of dopaminergic (DA) neurons in the midbrain. Induced pluripotent stem (iPS) cells have shown potential for differentiation and may become a resource of functional neurons for the treatment of PD. However, teratoma formation is a major concern for transplantation-based therapies. This study examined whether functional neurons could be efficiently generated from iPS cells using a five-step induction procedure combined with docosahexaenoic acid (DHA) treatment. We demonstrated that DHA, a ligand for the RXR/Nurr1 heterodimer, significantly activated expression of the Nurr1 gene and the Nurr1-related pathway in iPS cells. DHA treatment facilitated iPS differentiation into tyrosine hydroxylase (TH)-positive neurons in vitro and in vivo and functionally increased dopamine release in transplanted grafts in PD-like animals. Furthermore, DHA dramatically upregulated the endogenous expression levels of neuroprotective genes (Bcl-2, Bcl-xl, brain-derived neurotrophic factor, and glial cell-derived neurotrophic factor) and protected against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced apoptosis in iPS-derived neuronal precursor cells. DHA-treated iPS cells significantly improved the behavior of 6-hydroxydopamine (6-OHDA)-treated PD-like rats compared to control or eicosapentaenoic acid-treated group. Importantly, the in vivo experiment suggests that DHA induces the differentiation of functional dopaminergic precursors and improves the abnormal behavior of 6-OHDA-treated PD-like rats by 4 months after transplantation. Furthermore, we found that DHA treatment in iPS cell-grafted rats significantly downregulated the mRNA expression of embryonic stem cell-specific genes (Oct-4 and c-Myc) in the graft and effectively blocked teratoma formation. Importantly, 3 Tesla-magnetic resonance imaging and ex vivo green fluorescence protein imaging revealed that no teratomas were present in transplanted grafts of DHA-treated iPS-derived DA neurons 4 months after implantation. Therefore, our data suggest that DHA plays a crucial role in iPS differentiation into functional DA neurons and that this approach could provide a novel therapeutic approach for PD treatment.     

脂氧素A4对局灶性脑缺血再灌注大鼠血脑屏障通透性的影响

目的 探讨脂氧素A4对局灶性脑缺血再灌注大鼠血脑屏障通透性的影响.方法 健康成年雄性SD大鼠54只,体重200～250 g,随机分为3组(n=18):假手术组(S组)、局灶性脑缺血再灌注组(I/R组)和脂氧素A4组(L组).采用改良线栓法制备大鼠局灶性脑缺血再灌注损伤模型,阻断右侧大脑中动脉缺血2 h后行再灌注.L组缺血即刻右侧侧脑室注射脂氧素A4 100 ng,S组和I/R组右侧侧脑室注射等容量生理盐水5 μl.于再灌注24 h时行神经功能缺陷评分,静脉注射2%伊文斯蓝4 ml/kg,1 h后处死大鼠取脑,测定右侧脑水含量和伊文斯蓝含量,检测脑皮质基质金属蛋白酶9(MMP-9)的表达.结果 与S组比较,I/R组和L组神经功能缺陷评分、脑水含量和伊文斯蓝含量升高,脑皮质MMP-9表达上凋(P＜0.05或0.01);与I/R组比较,L组神经功能缺陷评分、脑水含量和伊文斯蓝含量降低,脑皮质MMP-9表达下调(P＜0.01).结论 脂氧素A4可降低血脑屏障通透性,减轻脑水肿,促进局灶性脑缺血再灌注损伤大鼠的神经功能恢复,其机制与抑制MMP-9表达上调有关.     

Real‐Time Trafficking of PEGylated Liposomes in the Rodent Focal Brain Ischemia Analyzed by Positron Emission Tomography

A liposomal drug delivery system was previously applied to ischemic brain model rats for the treatment of brain ischemia, and we observed that 100‐nm‐sized liposomes could extravasate and accumulate in the ischemic brain region even when cerebral blood flow was markedly reduced in permanent middle cerebral artery occlusion (p‐MCAO) model rats. In the present study, we investigated the real‐time cerebral distribution of polyethylene glycol (PEG)‐modified liposomes (PEG‐liposomes) labeled with 1‐[¹⁸F]fluoro‐3,6‐dioxatetracosane in p‐MCAO rats by positron emission tomography (PET). [¹⁸F]‐Labeled PEG‐liposomes were intravenously injected into p‐MCAO rats 1 h after the onset of occlusion, and then a PET scan was performed for 2 h. The PET scan showed that the signal intensity of [¹⁸F] gradually increased in the ischemic region despite the drastic reduction in cerebral perfusion, suggesting that PEG‐liposomes had accumulated in and around the ischemic region. Therefore, drug delivery to the ischemic region by use of liposomes would be possible under ischemic conditions, and a liposomal drug delivery system could be a promising strategy for protecting the ischemic brain from damage before recovery from ischemia.     

Increased expression of serum matrix metalloproteinase-9 in patients with moyamoya disease

Background

Moyamoya disease is a chronic occlusive cerebrovascular disease with unknown etiology characterized by an abnormal vascular network at the base of the brain, which can manifest both as ischemic stroke and as cerebral hemorrhage. It was also reported that the patients with moyamoya disease are more vulnerable to cerebral hyperperfusion such as postoperative hemorrhagic complication after extracranial-intracranial bypass surgery despite its low flow revascularization. However, the underlying mechanisms of its pathologic angiogenesis and the occurrence of hemorrhage are undetermined. Excessive degradation of the vascular matrix by MMPs, proteolytic enzymes that degrade all the components of extracellular matrix, can lead to instability of the vascular structure and can thereby cause bleeding. The MMPs also play an important role in tissue remodeling including angiogenesis in both physiologic and pathologic condition.

Methods

We examined the serum levels of MMP-2 and MMP-9 in 16 cases with definitive moyamoya disease by enzyme-linked immunosorbent assay and compared them with those from healthy controls.

Results

The serum MMP-9 level was significantly higher in moyamoya disease (40.18 ng/mL) than in healthy controls (13.75 ng/mL, P = .0372). There was no difference in serum MMP-2 level between moyamoya disease (646.65 ng/mL) and healthy control (677.60 ng/mL). Immunohistochemistry on the surgical specimens showed significant increase in MMP-9 expression within the arachnoid membrane of moyamoya disease.

Conclusion

The increased expression of MMP-9 may contribute to pathologic angiogenesis and/or to the instability of the vascular structure and could thereby cause hemorrhage in moyamoya disease.     

诱导的多潜能干细胞类胚体分化过程中残留未分化细胞的研究

目的：探讨诱导的多潜能干细胞（induced pluri potent stem cells,iPS cells）通过类胚体长期分化后残留未分化细胞的特性。方法：小鼠iPS细胞株,体外类胚体分化20天后消化打散,重新给予i PS细胞常规培养液培养。观察扩增的残留细胞形态;流式细胞仪和免疫荧光染色检测和观察残留细胞表面标志物及体外再次分化能力。将残留细胞扩增后注射入裸鼠背部皮下,6周后注射部位取材进行大体和组织学检查。结果：分化20天的类胚体中存在残留未分化的细胞,呈克隆样生长,高度表达SSEA-1、CD-9和OCT-4等多潜能性标志。残留细胞能反复传代,并可在体外再次分化和残留。残留细胞注射部位形成畸胎瘤,瘤体组织中存在成熟的内胚层、中胚层和外胚层组织。结论：iPS细胞分化为类胚体后残留部分未分化细胞,残留细胞在体内、外可再次分化,并能在体外分化中再次残留。     

Secretion of matrix metalloproteinase-2 and -9 after mechanical trauma injury in rat cortical cultures and involvement of MAP kinase

Matrix metalloproteinases (MMP) are involved in the pathophysiology of brain injury. We recently showed that knockout mice deficient in MMP-9 expression were protected against traumatic brain injury. However, the cellular sources of MMP activity after trauma remain to be fully defined. In this study, we investigated the hypothesis that resident brain cells secrete MMP after mechanical trauma injury in vitro, and mitogen-activated protein (MAP) kinase signal transduction pathways are involved in this response. Rat primary cortical neurons, astrocytes, and co-cultures were subjected to needle scratch mechanical injury, and levels of MMP-2 and MMP-9 in conditioned media were assayed by zymography. MMP-2 and MMP-9 were increased in cortical astrocytes and co-cultures, whereas only MMP-2 was increased in neurons. Western blots showed that phosphorylated extracellular signal regulated kinase (ERK1/2) and p38 were rapidly upregulated in co-cultures after mechanical injury. No change in phosphorylated c-jun N-terminal kinase (JNK) was observed. In-gel kinase assays confirmed this lack of response in the JNK pathway. Treatment with either 10 microM of U0126 (a MAP kinase/ERK1/2 kinase inhibitor) or 10 microM of SB203580 (a p38 inhibitor) had no detectable effect on MMP-2 and MMP-9 levels after mechanical injury. However, combination treatment with both inhibitors significantly reduced secretion of MMP-9. Herein, we demonstrate that (1) resident brain cells secrete MMP after mechanical injury, (2) astrocytes are the main source of MMP-9 activity, and (3) ERK and p38 MAP kinases are upregulated after mechanical injury, and mediate the secretion of MMP-9.     

Aggravation of infarct formation by brain swelling in a large territorial stroke: a target for neuroprotection?

OBJECT: In territorial stroke vasogenic edema formation leads to elevated intracranial pressure (ICP) and can cause herniation and death. Brain swelling further impairs collateral blood flow to the ischemic penumbra and causes mechanical damage to adjacent brain structures. In the present study the authors sought to quantify the impact of this space-occupying effect on ischemic lesion formation. METHODS: Wistar rats were assigned to undergo bilateral craniectomy or a sham operation and then were subjected to temporary middle cerebral artery occlusion (MCAO) for 90 minutes. A clinical evaluation and 7-T MR imaging studies were performed 5 and 24 hours after MCAO. The absolute brain water content was determined at 24 hours by using the wet/dry method. RESULTS: Bilateral craniectomy before MCAO led to a drastic reduction in lesion volume at both imaging time points (p < 0.0001). Ischemic lesion volume was 2.7- and 2.3-fold larger in sham-operated animals after 5 and 24 hours, respectively. Clinical scores were likewise better in rats that had undergone craniectomy (p < 0.05). After 24 hours the midline shift differed significantly between the 2 groups (p < 0.001), but not after 5 hours. The relation between brain water content and ischemic lesion volume as well as the T2 relaxation time within the infarcted area was not different between the groups (p > 0.05). CONCLUSIONS: The data indicated that collateral damage caused by the space-occupying effect of a large MCA territory stroke contributes seriously to ischemic lesion formation. The elimination of increased ICP thus must be regarded as a highly neuroprotective measure, rather than only a life-saving procedure to prevent cerebral herniation. Further clinical trials should reveal the neuroprotective potential of surgical and pharmacological ICP-lowering therapeutic approaches.     

Expression of matrix metalloproteinases 2 and 9 in meningiomas associated with different degrees of brain invasiveness and edema.

OBJECT: Meningiomas display clinical characteristics that vary from very benign to clearly malignant with rapid invasive growth and metastasis. Benign meningiomas differ in their invasiveness and concomitant edema. This study was undertaken to analyze the expression of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9, respectively) in meningiomas associated with different degrees of brain invasion and edema. METHODS: Tissue samples from 16 meningiomas were selected according to tumor invasiveness from a consecutive series of patients. Samples were analyzed for expression of both MMP-2 and MMP-9 by using in situ hybridization. The meningiomas consisted of three types: Group I, benign meningiomas that did not interfere with the arachnoid plane and exhibited no edema; Group II, benign meningiomas that invaded the arachnoid plane and caused edema; and Group III, aggressive and malignant meningiomas that caused edema and displayed brain invasion. In all 16 tumors analyzed, MMP-2 mRNA was identified. Levels of expression of MMP-2 mRNA were similar in all samples, and no correlation with increasing tumor invasiveness or associated edema could be detected. Expression of MMP-9 mRNA was identified in 14 of the 16 tumors, and a clear correlation with increasing tumor invasion into the brain was noted. CONCLUSIONS: Meningiomas express both MMP-2 and MMP-9. Tumor invasiveness, which ranged from minor with respect to the arachnoid membrane and progressed to frank brain invasion, correlated with the extent of MMP-9 expression. The findings indicate that MMP-9 expression and brain invasion are relevant mechanisms that must be interfered with in the treatment of aggressive and malignant meningiomas. No such correlation with MMP-2 was found.     

TIMP-1/MMP-9 imbalance in brain edema in rats with fulminant hepatic failure

BACKGROUND: Fulminant hepatic failure (FHF) is a devastating disease. When coma sets in, brain edema develops, changing FHF into a lethal condition. Liver transplantation is the definitive treatment. However, a third of these patients die as the result of brain edema before a donor becomes available. Tissue inhibitor of matrix metalloproteinase (MMP), or TIMP, and MMP-9 are implicated in ischemic brain edema. We thus hypothesized that an imbalance in TIMP-1/MMP-9 relationship plays a role in the development of increased brain extravasation and edema in FHF. MATERIALS AND METHODS: FHF was induced with a single intraperitoneal injection of D-galactosamine (250 mg/kg). Control rats received saline. GM6001, a synthetic MMP inhibitor, was administered (30 mg/kg) every 12 h for 3 doses starting at 12 h after D-galactosamine injection. MMP-9 was assayed with standard gelatin zymography. Brain extravasation, a measurement of the blood-brain barrier permeability, was determined with Evans blue. Brain edema was determined using specific gravity method. RESULTS: The active MMP-9 in the systemic circulation was significantly increased in the comatose FHF as compared to the precoma FHF and control animals (6.5 +/- 0.7 versus 4.6 +/- 0.4 versus 2.6 +/- 0.5 pg/microg, respectively; P < 0.05). Conversely, TIMP-1 was steadily decreased in precoma and coma FHF rats by 35% and 45%, respectively. Blocking MMP-9 activity with GM6001 significantly attenuated brain extravasation and edema in rats with FHF. CONCLUSIONS: Our study strongly supports that the perturbation of decreased TIMP-1 and increased MMP-9 contributes to the pathogenesis of brain edema in FHF. Our findings present a potential therapeutic approach to effectively increase the window of opportunity for life-saving liver transplantation.     

Teratoma formation and hepatocyte differentiation in mouse liver transplanted with mouse embryonic stem cell-derived embryoid bodies

We previously reported that mouse embryonic stem (ES) cells are capable of differentiating into hepatocytes in cultured embryoid bodies (EBs) and that hepatocytes generate in the recipient liver injected with cultured day-9 EB cells via spleen without the formation of a teratoma. Because ES cells frequently form teratomas in recipient mice, we investigated incidence of teratoma formation when day-9 EBs derived from ES cells were transplanted directly into the subcapsule of mouse liver. In contrast to injection of day-9 EB cells through the portal vein via the spleen, direct subcapsular injection of cultured day-9 EB cells into liver, and even of cultured day-15 EBs, resulted in an high incidence of teratoma in the liver. In teratomas of livers injected directly with day-15 EBs, hepatocytes were detected singly and in clusters. These results imply that undifferentiated cells capable of developing into teratomas exist in cultured EBs, and even in cultured day-15 EBs containing differentiated hepatocytes.     

Phospholipase C-γ Immunostaining in Human Breast Carcinoma: Clinical Significance and Correlations with Protease and Growth-Factor Receptor Species

Abstract: Cryostat sections of 73 invasive breast carcinomas were immunostained with a rabbit polyclonal antibody to phosphoinositide-specific phospholipase C-γ (PLC-γ), an enzyme that mediates signal transduction in tyrosine kinase growth-factor pathways. Degree of immunoreactivity was then correlated with clinicopathologic data (stage, ER status, recurrence) and immunostaining for tyrosine kinase growth-factor receptors (EGFR, ERBB-2) as well as selected "invasion-associated" proteases (cathepsin D, urokinase plasminogen activator, matrix metalloproteinases 2 and 9 [MMP-2, MMP-9]). Neoplastic epithelial populations were PLC-γ immunoreactive in 95% of tumors although staining was focally distributed (in <50% of cells) in 51% of positive cases. Forty-four percent also exhibited immunostaining of peritumoral, spindle-shaped cells (i.e., fibroblasts, endothelium, inflammatory cells). The degree of PLC-γ immunoreactivity in neoplastic epithelium was not significantly correlated with clinicopathologic features, growth factor receptor overexpression, or protease immunostaining. Stromal cell PLC-γ staining, however, was significantly associated with stromal cell immunoreactivity for cathepsin D (p = 0.03), urokinase plasminogen activator (p = 0.01), and MMP-2 (p = 0.04). Disease recurrences were also more frequent in tumors with stroma/spindle cell PLC-γ immunoreactivity (66% vs. 41%, p = 0.04). We conclude that PLC-γ immunostaining, compatible with increased tyrosine kinase pathway signaling activity, is observed not only in a high proportion of neoplastic breast epithelial populations but also in accompanying stromal cell populations in a significant number of cases. Concordance with protease immunoreactivity among peritumoral stromal cells suggests that tyrosine kinase signaling may participate in protease elaboration in vivo, possibly conferring aggressive clinical behavior.     

Noninvasive diagnosis of bladder cancer by detection of matrix metalloproteinases (MMP-2 and MMP-9) and their inhibitor (TIMP-2) in urine

OBJECTIVES: TIMPs control the activity of MMPs, one of the key molecules for tumor invasion and metastasis. The aim of this study was to assess the usefulness of MMP-2 and MMP-9 in relation to their inhibitor (TIMP2) as noninvasive diagnostic tests for bilharzial bladder cancer. MATERIAL AND METHODS: Voided urine samples were provided from 244 subjects (154 bladder cancer [136 bilharzial]; 60 benign urologic disorders; 30 healthy volunteers). Urine sediment was used for cytology, and the supernatant for estimation of MMPs and TIMP-2 by ELISA and gelatin zymography. RESULTS: The best cut-off values for the investigated markers were determined by ROC curve. Positivity rates and median levels for MMP-2, MMP-9, TIMP-2, MMP-2/TIMP-2, and MMP-9/TIMP-2 showed significant difference among the three investigated groups (p<0.001). MMP-9 and MMP-2/TIMP-2 were related to pathologic type, MMP-2/TIMP-2 was inversely related to the grade, and MMP-9/TIMP-2 was related to bilharziasis (p<0.05). MMP zymography results were comparable to those from ELISA. CONCLUSION: The sensitivity and specificity of MMP zymography, MMP-9/TIMP-2 ratio, and MMP-2/TIMP2 ratio were superior among all investigated parameters; furthermore, combined testing of cytology with them improves the sensitivity even in superficial and low-grade tumors.     

基质金属蛋白酶2,9及金属蛋白酶组织抑制剂1在肾盂移行细胞癌中的表达及意义

目的 探讨基质金属蛋白酶2（MMP-2），9（MMP-9）及金属蛋白酶组织抑制剂1（TIMP-1）表达与肾盂移行细胞癌分级、分期及预后的关系。方法 采用免疫组化SP法检测117例肾盂移行细胞癌标本MMP-2，MMP-9发TIMP-1表达水平。患者中男97例，女20例。平均年龄59岁。肿瘤病理分级：G123例、G273例、G321例；TNM病理分期：Ta22例、T127例、T221例、T325例、T422例。结果 肾盂癌组织MMP-2表达阳性率81．2％（95例），MMP-9表达阳性率72．6％（85例），TIMP1表达阳性率72．6％（85例），阳性表达强度和阳性细胞分布不均匀，主要位于肿瘤细胞的胞质，随肿瘤分级、分期增加，MMP-2、MMP-9阳性表达率呈递增趋势，FL与预后相关，差异有统计学意义（P〈0．05）。TIMP-1阳性表达率随分级、分期增加呈递减趋势，但其差异无统计学意义（P〉0．05），TIMP-1表达强度与患者的生存时间无明显相关性。单因素方差分析发现MMP-9／TIMP-1比值与肿瘤临床病理分级、分期密切相关，随着分级、分期增加呈递增趋势（P〈0．05）。结论 MMP-2及MMP-9检测在肾盂癌病理分级、分期中有重要价值。MMP-2、MMP-9及MMP-9／TIMP-1比值在肾盂癌的预后判断中有重要意义。