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Results for “Staining and Labeling”

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At least 163 records · Page 9Linked to original sources

PubMed2003

BETA2/NeuroD1 null mice: a new model for transcription factor-dependent photoreceptor degeneration.

BETA2/NeuroD1 is a basic helix-loop-helix transcription factor that is expressed widely throughout the developing nervous system. Previous studies have shown that BETA2/NeuroD1 influences the fate of retinal cells in culture. To analyze the effect of BETA2/NeuroD1 on the structure and function of the retina, we examined a line of BETA2/NeuroD1 knock-out mice that survives until adulthood. At 2-3 months of age, homozygous null mice showed a 50% reduction in rod-driven electroretinograms (ERGs) and a 65% reduction in cone-driven ERGs. ERGs measured from knock-out mice that were >9 months of age were undetectable. At 2-3 months, the number of photoreceptors in the outer nuclear layer was reduced by 50%. In addition, electron microscopy showed that the surviving photoreceptors had shortened outer segments. The number of cones labeled by peanut agglutinin was decreased 50-60%. By 18 months, retinas from null mice were completely devoid of photoreceptors. There appeared to be few changes in the inner retina, although BETA2/NeuroD1 is expressed in this area. Terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling staining revealed a dramatic increase in cell death, peaking at approximately postnatal day 3 and continuing into adulthood. No defects in cell birth were detected using bromodeoxyuridine staining. Our results reveal that BETA2/NeuroD1 not only plays an important role in terminal differentiation of photoreceptors but also serves as a potential survival factor. Loss of BETA2/NeuroD1 results in an age-related degeneration of both rods and cones.

Animals↗

PubMed2002

Interleukin-13 and -4 induce death of activated microglia.

When the brain suffers injury, microglia migrate to the damaged sites and become activated. These activated microglia are not detected several days later and the mechanisms underlying their disappearance are not well characterized. In this study, we demonstrate that interleukin (IL)-13, an anti-inflammatory cytokine, selectively induces cell death of activated microglia in vitro. Cell death was detected 4 days after the coaddition of IL-13 with any one of the microglial activators, lipopolysaccharide (LPS), ganglioside, or thrombin. This cell death occurred in a time-dependent manner. LPS, ganglioside, thrombin, or IL-13 alone did not induce cell death. Among anti-inflammatory cytokines, IL-4 mimicked the effect of IL-13, while TGF-beta did not. Cells treated with IL-13 plus LPS, or IL-13 plus ganglioside, showed the characteristics of apoptosis when analyzed by electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining. Electron micrographs also showed microglia engulfing neighboring dead cells. We propose that IL-13 and IL-4 induce death of activated microglia, and that this process is important for prevention of chronic inflammation that can cause tissue damage.

Animals↗

PubMed2003

TorsinA protects against oxidative stress in COS-1 and PC12 cells.

Dystonia is a highly frequent movement disorder, the pathogenesis of which remains unclear. The cloning of TorsinA, the gene responsible for early-onset dystonia, was a major breakthrough. However, the function of this protein remains unclear. By sequence homology, TorsinA belongs to the ATPases associated with diverse cellular activities-family, many of whose members are chaperones and/or proteases. We report here that in an in vitro model for oxidative stress, H2O2 treatment, overexpression of TorsinA was protective against cell death. COS-1 cells overexpressing TorsinA demonstrated drastically reduced terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling-staining following exposure to H2O2. Furthermore, transfection with TorsinA significantly increased survival of PC12 after H2O2 treatment. To our knowledge, this is the first demonstration that TorsinA protects against oxidative stress. We speculate that a loss of this cellular function in mutant TorsinA may be linked to the pathogenesis of early-onset dystonia.

Animals↗

PubMed2000

Antisense TRPM-2 oligodeoxynucleotides chemosensitize human androgen-independent PC-3 prostate cancer cells both in vitro and in vivo.

Although numerous chemotherapeutic regimens have been evaluated for patients with hormone-refractory prostate cancer, none has improved survival. Testosterone-repressed prostate message-2 (TRPM-2), which is highly up-regulated after androgen withdrawal and during androgen-independent progression in prostate cancer, has been shown to inhibit apoptosis induced by various kinds of stimuli. The objectives in this study were to test whether antisense (AS) oligodeoxynucleotides (ODNs) targeted against TRPM-2 enhance chemosensitivity in human androgen-independent prostate cancer PC-3 cells both in vitro and in vivo. Initially, the potency of 10 AS ODNs targeting various regions of the TRPM-2 mRNA were evaluated, and the AS ODN targeted to the TRPM-2 translation initiation site (AS ODN#2) was found to be the most potent sequence for inhibiting TRPM-2 expression in PC-3 cells. Despite significant dose-dependent and sequence-specific suppression of TRPM-2 expression, AS ODN#2 had no effect on growth of PC-3 cells both in vitro and in vivo. However, pretreatment of PC-3 cells with AS ODN#2 significantly enhanced chemosensitivity of Taxol (paclitaxel) and mitoxantrone in vitro. Characteristic apoptotic DNA laddering and cleavage of poly(ADP-ribose) polymerase were observed after combined treatment with AS ODN#2 plus paclitaxel or mitoxantrone but not with either agent alone. In vivo administration of AS ODN#2 plus either paclitaxel or mitoxantrone significantly decreased PC-3 tumor volume by 80 or 60%, respectively, compared with mismatch control ODN plus either paclitaxel or mitoxantrone. In addition, terminal deoxynucleotidyl transferase-mediated nick end labeling staining revealed increased apoptotic cells in tumors treated with AS ODN#2 plus paclitaxel or mitoxantrone. These findings confirm that TRPM-2 overexpression confers resistance to cytotoxic chemotherapy in prostate cancer cells and illustrates the potential utility of combined treatment with AS TRPM-2 ODN plus chemotherapeutic agents for patients with hormone-refractory prostate cancer.

Androgens↗

PubMed2001

Smooth muscle cell changes during flow-related remodeling of rat mesenteric resistance arteries.

To obtain information on the molecular and cellular mechanisms of flow-induced arterial remodeling, we analyzed the morphology and smooth muscle cell (SMC) characteristics in rat mesenteric resistance arteries after interventions that decreased and increased flow. Juvenile male Wistar Kyoto rats were subjected to surgery that, compared with control arteries, provided arteries with chronic low flow and chronic high flow. Low flow resulted in a decreased passive lumen diameter, hypotrophy of the artery wall, and both loss and decreased size of SMCs. Time course studies, with intervention length ranging from 2 to 32 days of altered blood flow, showed that the narrowing of the lumen diameter in low-flow arteries appeared within 2 days and that an early dedifferentiation of SMC phenotype was indicated by markedly reduced levels of desmin mRNA. High flow resulted in an increased passive lumen diameter and in hypertrophy of the artery wall. The hypertrophy resulted from SMC proliferation because SMC number, measured by the 3D-dissector technique, was increased and immunohistochemical assessment of proliferating cell nuclear antigen also showed an increase. The widening of high-flow arteries required 16 days to become established, at which time desmin mRNA was reduced. This time was also required to establish changed wall mass in both low-flow and high-flow arteries. Apoptotic cells detected by TdT-mediated dUTP-biotin nick end labeling staining were mainly located in the medial layer, and evaluation of DNA fragmentation indicated that increased apoptosis occurred in both low flow and high flow. This study shows for the first time direct evidence that reduced and elevated blood flow in resistance arteries produce, respectively, decrease and increase in SMC number, with dedifferentiation of the SMCs in both cases.

Animals↗

PubMed2001

Transient massive DNA fragmentation in nervous system during the early course of a murine neurodegenerative disease.

In neurodegenerative diseases, such as Alzheimer's disease or HIV encephalitis, neuronal DNA fragmentation has been observed at unexpected high frequencies, without definitive evidence for activation of an irreversible apoptotic pathway. The wobbler mouse is a suggested genetic model of neurodegenerative disease. The mutant mouse develops normally until the fourth week of age when atrophy and weakness of forelimb muscles become apparent. There is a slow progression of the disease and wobbler mice may survive for several months. Spinal cord examination reveals the presence of several motoneurons with perikaryal vacuolar degeneration. In this study, we observed, using terminal dUTP nick-end-labelling staining in mutant spinal cord sections, a massive although very transient DNA fragmentation in different cell types, including glial cells and motoneurons, before the apparition of any clinical symptoms. In older wobbler mice, this DNA fragmentation had completely disappeared and the majority of motoneurons survived. To our knowledge, this is the first example of a massive and transient DNA fragmentation in the central nervous system during the early course of a neurodegenerative disease.

Aging↗

PubMed2001

2, 3, 7, 8-tetrachlorodibenzo-p-dioxin induces apoptosis in the dorsal midbrain of zebrafish embryos by activation of arylhydrocarbon receptor.

Neurotoxic effects of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) has not been fully elucidated, despite the known potent agonist of arylhydrocarbon receptor (AhR), which activation induces cytochrome P450 1A and several representative toxicities of halogenated aromatic hydrocarbons. In the present study, the effects of TCDD on cell death in zebrafish embryos (Danio rerio) during the early stage of development were investigated. As shown by terminal transferase-mediated nick-end-labeling staining, TCDD exposure significantly increased the occurrence of pycnotic cell death (PCD), especially in the dorsal midbrain (optic tectum). The ultrastructures of these pycnotic cells showed apoptotic features such as condensation and cleavage of chromatin. TCDD-induced PCD was mimicked by beta-naphthoflavone (AhR agonist), and inhibited by alpha-naphthoflavone (AhR antagonist). These results suggest that AhR activation can induce apoptosis in the central nervous system during development.

Animals↗

PubMed1988

Static and tetracycline-based bone histomorphometric data from 34 normal postmenopausal females.

Transilial bone biopsies were obtained from 34 healthy postmenopausal women following in vivo fluorochrome labeling. Stained and unstained undecalcified sections were evaluated using a Merz grid. Standard histomorphometric data from cancellous bone tissue were collected and the results were evaluated and presented as variables commonly used in bone histomorphometry. The normal ranges, medians, means, and standard deviations for the group of 34 are presented in tabular form for structural, surface, basic dynamic, and derived dynamic data. Similar data for individuals grouped by ages 45-54, 55-64, and 65-74 are also presented. Secular trends for the whole group are evaluated. The structural and surface data are not much different from previous reports of sudden-death accident victims, when methodologic differences are considered. The mineral apposition rate (MAR) was 0.53 +/- 0.08 micron/day, similar to previous reports in cancellous bone, but one-third less than in cortical bone. MAR showed a marked decline with age. In contrast, the extent of tetracycline-labeled surfaces varied widely without a secular trend. Double-label surface (dLS/BS) ranged from 0.5 to 8.0% and single-label surface (sLS/BS), from 0.5 to 10.5%. Mineralizing osteoid surface (MS/OS) varied from 2 to 64%. Using only double-label surface to represent mineralizing surface, volume-based bone formation rate (BFR/BV) ranged from 0.7 to 28%/yr, and the remodeling period (Rm.P) varied from 0.28 to 4.5 years. Calculations using other representations of mineralizing surface [double plus one-half single label (MS/BS"); all label (MS/BS')] are also presented. These bone histomorphometric data are important because: (1) they come from a cohort of living subjects that was recruited solely for the purpose of establishing normal bone histomorphometry; (2) they represent the age range of patients with postmenopausal osteoporosis; and (3) they markedly expand the bone histomorphometric database of healthy persons given in vivo fluorochrome labeling prior to transilial biopsy.

Aged↗

PubMed2002

Glucagon-like peptide-1 promotes islet cell growth and inhibits apoptosis in Zucker diabetic rats.

A constant remodeling of islet cell mass mediated by proliferative and apoptotic stimuli ensures a dynamic response to a changing demand for insulin. In this study, we investigated the effect of glucagon-like peptide-1 (GLP-1) in Zucker diabetic rats, an animal model in which the onset of diabetes occurs when the proliferative potential and the rate of beta-cell apoptosis no longer compensate for the increased demand for insulin. We subjected diabetic rats to a 2-d infusion of GLP-1 and tested their response to an ip glucose tolerance test. GLP-1 produced a significant increase of insulin secretion, which was paralleled by a decrease in plasma glucose levels (P < 0.001 and P < 0.01, respectively). Four days after the removal of the infusion pumps, rats were killed and the pancreas harvested to study the mechanism by which GLP-1 ameliorated glucose tolerance. Ex vivo immunostaining with the marker of cell proliferation, Ki-67, showed that the metabolic changes observed in rats treated with GLP-1 were associated with an increase in cell proliferation of the endocrine and exocrine component of the pancreas. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling staining, a marker of cellular apoptosis, indicated a reduction of apoptotic cells within the islet as well in the exocrine pancreas in GLP-1-treated rats. Double immunostaining for the apoptotic marker caspase-3 and for insulin showed a significant reduction of caspase-3 expression and an increase in insulin content in GLP-1-treated animals. Finally, staining of pancreatic sections with the nuclear dye 4,6-Diaminidino-2-phenyl-dihydrochloride demonstrated a marked reduction of fragmented nuclei in the islet cells of rats treated with GLP-1. Our findings provide evidence that the beneficial effects of GLP-1 in Zucker diabetic rats is mediated by an increase in islet cell proliferation and a decrease of cellular apoptosis.

Animals↗

PubMed2002

Inhibition of the phosphatidylinositol 3'-kinase-AKT pathway induces apoptosis in pancreatic carcinoma cells in vitro and in vivo.

The phosphatidylinositol 3'-kinase (PI3k)-AKT survival pathway is activated in many malignancies. We observed constitutive AKT phosphorylation (on S473) consistent with pathway activation in seven of nine human pancreatic carcinoma cell lines in vitro. Exposure of the cells to two structurally distinct inhibitors of PI3k (worthmannin and LY294002) resulted in a dose-dependent induction of apoptosis in six of seven of the cell lines that displayed constitutive AKT phosphorylation but not in either of the cell lines that did not. The mitogen-activated protein/extracellular signal-regulated kinase kinase-mitogen-activated protein kinase inhibitor PD98059 also induced apoptosis in two of the cell lines, including one of the LY294002-insensitive lines (AsPC-1). Exposure of orthotopic L3.6pl pancreatic tumors to LY294002 resulted in dose-dependent inhibition of tumor growth, and decreased peritoneal and liver metastases, effects that were associated with an inhibition of AKT phosphorylation and increased terminal deoxynucleotidyl transferase-mediated nick end labeling staining characteristic of apoptosis. Furthermore, a suboptimal dose of LY294002 (25 mg/kg) produced additive inhibition of tumor growth when combined with a suboptimal dose of gemcitabine (62 mg/kg). Together, our results establish that the PI3k/AKT pathway is constitutively activated in a majority of human pancreatic cancer cell lines and establish that the pathway is a promising target for therapeutic intervention.

Androstadienes↗

PubMed2001

In situ demonstration of phosphorylated c-jun and p38 MAP kinase in epidermal keratinocytes following ultraviolet B irradiation of human skin.

Ultraviolet B (UVB) irradiation is known to induce activation of cellular stress response pathways in cultured cells or intact human skin, as demonstrated by phosphorylation of MAP kinase family members and up- or down-stream targets, using biochemical assays. This study demonstrates by immunohistochemistry that low-dose UVB irradiation of normal human skin induces rapid and reversible phosphorylation of c-jun (a target of c-jun N-terminal kinase) and p38 mitogen activated protein kinase (p38 MAP kinase). Phosphorylation was maximal at 4-8 h and returned to normal levels at 48 h after irradiation. Nuclear localization of these phosphorylated substrates was found using antisera against the epitope containing the phosphorylated serine-73 of c-jun, and the dually phosphorylated epitope (threonine-180 and tyrosine-182) of p38 MAP kinase. Nearly all epidermal cells were positive for c-jun phosphorylation, whereas p38 phosphorylation was seen predominantly in the differentiated layers. In contrast to the massive activation of c-jun and p38, only a small population of the suprabasal cells showed nuclear translocation of nuclear factor kappa B (NFkappaB), and a few scattered cells became apoptotic, as determined by TUNEL (TdT mediated dUTP nick end labelling) staining. The expression of involucrin and skin-derived anti-leukoproteinase (SKALP)/elafin, two genes putatively under control of the c-jun and p38 pathways, was found to be increased. These findings establish the first cellular localization of UVB-induced protein phosphorylation of stress response proteins in human epidermis, thereby providing a link between cellular activation and gene expression in defined cell populations.

Adolescent↗

PubMed2002

Tumor necrosis factor alpha, but not Fas, mediates hepatocellular apoptosis in the murine ischemic liver.

BACKGROUND & AIMS: Apoptosis of hepatocytes is a central feature of ischemic injury in the liver. The aim of this study was to identify extracellular inducers of apoptosis in the murine ischemic liver. METHODS: Involvement of tumor necrosis factor (TNF)-alpha and Fas signaling was evaluated using various knockout mice (TNF-receptor 1 [TNF-R1]-/-, Fas[lpr]-/-, and Fas ligand[gld]-/-) and wild-type mice pretreated with pentoxifylline, an inhibitor of TNF-alpha synthesis. RESULTS: Expression of TNF-alpha was increased after ischemia and reperfusion in wild-type mice and TNF-R1-deficient mice when compared with sham-operated animals. Pentoxifylline prevented up-regulation of TNF-alpha expression. Inhibition of TNF-alpha resulted in significant decrease of serum aspartate aminotransferase levels and prolonged animal survival. Markers of apoptosis (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining, cytochrome C release, and caspase 3 activity) were consistently decreased, and animal survival was prolonged after blocking TNF-alpha. In contrast, inhibition of Fas signaling did not alter parameters of tissue injury or apoptosis, and animal survival remained unchanged. CONCLUSIONS: We identify TNF-alpha as a crucial inducer of apoptotic cell death in the ischemic liver. A role for Fas could not be identified. These findings may lead to novel strategies to prevent ischemic injury of the liver.

Animals↗

PubMed2002

Neuroprotective effect of eicosapentaenoic acid in hippocampus of rats exposed to gamma-irradiation.

Exposure to irradiation leads to detrimental changes in several cell types. In this study we assessed the changes induced in hippocampus by exposure of rats to whole body irradiation; the findings reveal that irradiation leads to apoptotic cell death in hippocampus, and as a consequence, long term potentiation in perforant path-granule cell synapses is markedly impaired. The evidence is consistent with the view that irradiation induced an increase in reactive oxygen species and that this leads to stimulation of the stress-activated protein kinase, JNK, and activation of the transcription factor, c-Jun. Consequent upon activation of JNK, a cascade of cell signaling events was stimulated that ultimately resulted in apoptosis, as suggested by parallel increases in cytochrome c translocation, caspase-3 activation, poly(ADP-ribose) polymerase cleavage, and terminal dUTP nick-end labeling staining. Treatment of rats with eicosapentaenoic acid inhibited the irradiation-induced increase in reactive oxygen species production and the subsequent cellular signaling events, suggesting that oxidative stress triggered apoptotic cell death in the hippocampus of rats exposed to irradiation. Significantly, when the compromise in cell viability induced by irradiation was prevented by eicosapentaenoic acid, long term potentiation was sustained in a manner similar to that in the sham-treated control group.

Animals↗

PubMed2002

Group B streptococcal beta-hemolysin induces mortality and liver injury in experimental sepsis.

New Zealand White rabbits were challenged with the wild-type (wt) group B streptococci (GBS) serotype III strain (COH1) and its isogenic nonhemolytic (NH) and hyperhemolytic (HH) mutants. Mortality differed significantly between rabbits infected with the HH mutant IN40 (67%), compared with rabbits infected with the wt COH1 strain (27%) and the NH strains COH1-20 and COH1:cylEDeltacat (13% and 0%, respectively; P<.05). Histopathologically, disseminated septic microabscesses surrounded by necrotic foci were found exclusively in the livers of HH mutant IN40-infected animals. Serum transaminase levels were 20-fold higher in the HH-infected group, compared with rabbits infected with the other strains. Positive TUNEL (in situ terminal deoxynucleotide transferase-mediated dUTP nick end labeling) staining and activation of caspase-3 in hepatocytes were more frequent in HH-infected than in wt-infected animals and absent in the NH mutant COH1-20-infected group, indicating that GBS beta-hemolysin triggers apoptotic pathways in hepatocytes. This work provides the first evidence that GBS beta-hemolysin plays a crucial role in the pathophysiology of GBS sepsis by inducing liver failure and high mortality.

Animals↗

PubMed2006

Altered tapetal PCD and pollen wall development in the Arabidopsis ms1 mutant.

The Arabidopsis male sterility1 mutation results in mature anthers that are devoid of pollen. Meiosis and early development progress normally; however, after microspore release, the microspore cytoplasm and tapetum become abnormally granular and vacuolated, and degeneration occurs. Pollen wall development is seriously affected; primexine formation within the callose wall appears to occur normally, however, once the callose is degraded, abnormal deposits of electrodense material are detected which result in irregular spike-shaped structures, rather than the characteristic rod-like shape of the wild-type bacula. The internal intine wall is also reduced compared with wild type. TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling) staining and ultrastructural analysis have indicated that programmed cell death (PCD) occurs in the wild-type tapetum after microspore mitosis I. However, no signs of PCD are seen in the ms1 tapetum, where large autophagic vacuoles and mitochondrial swelling suggest that necrotic-based breakdown of the tapetum is occurring in the ms1 mutant rather than the normal, regulated PCD process. After the formation of the large, autophagic vacuole in the tapetum, TUNEL staining is detected in the mutant microspores, indicating that they may go through a PCD-based breakdown as a secondary consequence of the observed tapetal aberrations. Based on these observations, two possible roles for MS1 can be hypothesized; MS1 may function by modifying the transcription of tapetal-specific genes implicated in pollen wall development, which then regulate pollen wall material secretion and in turn wall development and tapetal PCD. Alternatively, the MS1 gene may control tapetal development by directly regulating tapetal PCD and breakdown.

Apoptosis↗

PubMed2000

Pulmonary hypoplasia in the myogenin null mouse embryo.

Although fetal breathing movements are required for normal lung development, there is uncertainty concerning the specific effect of absent fetal breathing movements on pulmonary cell maturation. We set out to evaluate pulmonary development in a genetically defined mouse model, the myogenin null mouse, in which there is a lack of normal skeletal muscle fibers and thus skeletal muscle movements are absent in utero. Significant decreases were observed in lung:body weight ratio and lung total DNA at embryonic days (E)14, E17, and E20. Reverse transcriptase/polymerase chain reaction, in situ immunofluorescence, and electron microscopy revealed early lung cell differentiation in both null and wild-type lungs as early as E14. However at E14, myogenin null lungs had decreased 5'-bromo-2-deoxyuridine incorporation compared with that of wild-type littermates, whereas at E17 and E20, increased Bax immunolabeling and terminal deoxyribonucleotidyl transferase-mediated dUTP-biotin nick-end labeling staining were detected in the myogenin null mice but not in the wild-type littermates. These observations highlight the importance of skeletal muscle contractile activity in utero for normal lung organogenesis. Null mice lacking the muscle-specific transcription factor myogenin exhibit a secondary effect on lung development such that decreased lung cell proliferation and increased programmed cell death are associated with lung hypoplasia.

Animals↗

PubMed2003

Cellular mechanism of thymic involution.

Involution of the thymus and alterations in the development of thymocytes are the most prominent features of age-related immune senescence. We have carried out a comparative analysis of thymocyte and stroma in rapid thymic involution DBA/2 (D2) strain of mice compared with slow involution C57BL/6 (B6) strain of mice. Analysis of mice at 15 months of age suggested an age-related decrease in the thymocyte cell count, a block in the development of T cells and cortical involution in D2 mice compared with 3-month-old mice. TUNEL (terminal-deoxynucleotidyl-transferase-mediated dUTP-digoxigenin nick end labelling) staining and fluorescence-activated cell sorter (FACS) analysis showed that there was a significant increase in apoptotic cells in the cortex region of thymus in 15-month-old D2 mice compared with the same aged B6 mice. The thymocyte proliferation rate, as assessed by bromodeoxyuridine (BrdU) staining and [3H]-thymidine incorporation assay, was lower in 3-month-old D2 mice compared with the same age B6 mice. Immunohistochemical staining showed that the arrangement of MTS (mouse thymus stromal)-10+ epithelial cells and MTS-16+ connective tissue staining pattern had become disorganized in 15-month-old D2 mice but remained intact in B6 mice of the same age. These results suggest that, in D2 mice, both the thymocytes and stromal cells exhibit age-related defects, and that the genetic background of mice plays an important role in determining age-related alterations in thymic involution.

Aging↗

PubMed2006

Chronic recurrent myocardial ischemic injury is significantly attenuated by pre-emptive adeno-associated virus heme oxygenase-1 gene delivery.

OBJECTIVES: We assessed the hypothesis that overexpression of the antioxidant enzyme heme oxygenase (HO)-1 may protect against chronic recurrent ischemia/reperfusion injury. BACKGROUND: Multiple and recurring episodes of myocardial ischemia can result in significant myocardial damage, including myocyte death, fibrosis, and wall thinning, leading to impaired ventricular function and cardiac failure. METHODS: In this study we used a closed-chest rodent model of chronic recurring myocardial ischemia and reperfusion to investigate the efficacy of pre-emptive gene therapy in overexpressing the antioxidant enzyme HO-1, using adeno-associated virus (AAV)-2 as the delivery vector. RESULTS: We show that constitutive overexpression of HO-1 can prevent myocardial wall thinning, inflammation, fibrosis, and deterioration of cardiac function (as measured by echocardiography, histology, and immunohistochemistry) induced by repeated transient myocardial ischemia and reperfusion injury. With HO-1 therapy, there was a significant reduction in apoptosis as determined by levels of markers of survival proteins and terminal deoxynucleotidyltransferase dUTP nick end-labeling staining. This prevention of tissue damage was also associated with reduction in superoxide generation. CONCLUSIONS: Taken together we provide the first evidence of the therapeutic efficacy of pre-emptive AAV-HO-1 delivery for prevention against multiple ischemic injury. This approach protects myocytes by simultaneously activating protective response and inhibiting pathological left ventricular remodeling and, therefore, may be a useful cardio-protective strategy for patients with coronary artery disease at a high risk for recurrent myocardial ischemia.

Animals↗