Guidelines on retention of pathology records and materials (Version 2/2022)

No abstract available.

[Comparative study of decentration, tilt and visual quality after implantation of aspherical intraocular lenses]

Objective: To compare the difference of decentration and tilt among 4 kinds of aspherical intraocular lenses (IOLs), and to analyze their objective visual quality. Methods: Prospective non-randomized controlled clinical trial. Age-related cataract patients who planned to undergo phacoemulsification and IOL implantation in the Affiliated Hospital of North Sichuan Medical College from April to June in 2020 were divided into ZCB00 group, SN60WF group, A1-UV group, and AO group according to IOL types. Thirty right eyes and thirty left eyes were selected in each group. Before operation and at 1 day, 1 week and 1 month postoperatively, decentration and tilt values were measured by a new swept-source anterior-segment optical coherence tomography device (CASIA2), and wavefront aberrations, objective scatter index (OSI), modulation transfer function cut off frequency (MTF cut off) and Strehl ratio (SR) were also examined. Values of decentration, tilt and visual quality compared among 4 groups were took from the right eye. One-way analysis of variance was used for inter-group comparison, and repeated measurement one-way analysis of variance was used for intra-group comparison. Data between right eyes and left eyes from all the individuals were compared by independent sample t-test. Results: A total of 181 patients (240 eyes) were enrolled, and 169 patients (224 eyes) completed the follow-up (114 right eyes and 110 left eyes). There were 77 males and 92 females, with an age of (69±9) years. There was no significant difference in gender, age, axial length, decentration and tilt of crystalline lens and IOL power among 4 groups (all P>0.05). At 1 day, 1 week and 1 month postoperatively, there was significant difference in decentration value among 4 groups (F=7.11, 6.12, 4.66; all P<0.05). For further pairwise comparison, the decentration value of SN60WF group was higher than that of the other 3 groups at 1 day and 1 week postoperatively, and the decentration value of SN60WF group was (0.259±0.101) mm at 1 month postoperatively, which was higher than that of ZCB00 group (0.177±0.099) mm and AO group (0.163±0.122) mm, and the differences were statistically significant (using SNK-q test, both P<0.05). The IOL tilt value in the ZCB00 group, SN60WF group, A1-UV group, and AO group at 1 month postoperatively were (4.806±1.129)°, (5.080±1.309)°, (4.586±1.338)°, (5.112±1.406)°, respectively. No significant difference in tilt value among 4 groups was found at any time after surgery (all P>0.05). In each group, there was no significant difference in decentration and tilt value at different postoperative time points (all P>0.05). At 1 month postoperatively, there was no significant difference in decentration and tilt at horizontal and vertical directions respectively among 4 groups (all P>0.05), and in each group, there was no significant difference in decentration and tilt value between right eyes and left eyes (all P>0.05), and IOLs tended to tilt towards the inferonasal or inferotemporal direction in both eyes. With 4-mm and 6-mm pupil diameter, there was significant difference in internal (F=131.32, 85.17) and ocular (F=46.64, 47.55) spherical aberration among 4 groups (all P<0.01). For further pairwise comparison, the spherical aberration of AO group was higher than that of the other 3 groups, and the difference was statistically significant (using SNK-q test, all P<0.05). There was no significant difference in OSI, MTF cut off and SR among 4 groups (all P>0.05). Conclusions: The four types of IOLs show decentration and tilt in varying degrees after implantation in the capsular bag, but this difference do not lead to clinical significance. Human eyes have tolerance to mild decentration and tilt of aspheric IOLs, showing good visual quality.

[Effect of endoplasmic reticulum stress induced by all-trans retinoic acid on apoptosis of FLT3-ITD mutated leukemia cells by activating autophagy in FLT3-ITD mutated protein]

Objective: Endoplasmic reticulum stress(ERS)was used as the research emphasis to further investigate the mechanisms of apoptosis of FLT3-ITD-mutated leukemia cells and decreased expression of FLT3-ITD mutated protein induced by all-trans retinoic acid(ATRA). Methods: FLT3-ITD-mutated leukemia cell lines(MV4-11 and MOLM13)were treated with ATRA. Flow cytometry was conducted to assess cell apoptosis. Real-time fluorescent quantitative PCR(RT-qPCR)and Western blot were used to detect the expression of ERS-related and autophagy-related genes and protein, respectively. Results: A low-dose ATRA further increased FLT3-ITD cells and ERS levels. ATRA acted on the ERS-related PERK/eif2ɑ signaling pathway and continued to increase the ERS of FLT3-ITD cells, resulting in an upregulation of apoptotic gene CHOP expression. After the treatment with ATRA, FLT3-ITD protein in FLT3-ITD cells was decreased. Of the two main ERS-related protein degradation pathways, ER-associated degradation(ERAD)and ER-activated autophagy(ERAA), the expression of ERAD-related protein ATF6 in FLT3-ITD cells was not significantly changed on ATRA, whereas the expression of ERAA-related proteins Atg7 and Atg5 were significantly increased. Conclusions: ATRA further raises the ERS level of FLT3-ITD cells continuously by activating the ERS-related PERK/eif2ɑ signal pathway and induces FLT3-ITD protein autophagy degradation through ERAA pathway, which induces apoptosis of FLT3-ITD-mutated leukemia cells. These results provide preliminary evidence on the use of ATRA in the treatment of refractory leukemia with FLT3-ITD.

Polar meron lattice in strained oxide ferroelectrics

A topological meron features a non-coplanar structure, whose order parameters in the core region are perpendicular to those near the perimeter. A meron is half of a skyrmion, and both have potential applications for information carrying and storage. Although merons and skyrmions in ferromagnetic materials can be readily obtained via inter-spin interactions, their behaviour and even existence in ferroelectric materials are still elusive. Here we observe using electron microscopy not only the atomic morphology of merons with a topological charge of 1/2, but also a periodic meron lattice in ultrathin PbTiO₃ films under tensile epitaxial strain on a SmScO₃ substrate. Phase-field simulations rationalize the formation of merons for which an epitaxial strain, as a single alterable parameter, plays a critical role in the coupling of lattice and charge. This study suggests that by engineering strain at the nanoscale it should be possible to fabricate topological polar textures, which in turn could facilitate the development of nanoscale ferroelectric devices.

Extramedullary CD20-positive B-lymphoblastic lymphoma in a 5-year-old child: A diagnostic challenge

Lymphoblastic leukaemia/lymphoma may present as an isolated extramedullary mass, which includes the musculoskeletal region involvement with normal or near-normal blood counts. The tumour may be in the form of B or T-lymphoblastic leukaemia/lymphoma. The clinical features and histological morphology of extramedullary B-lymphoblastic lymphoma (B-LBL) may mimic mature B-cell neoplasms, thus posing a diagnostic challenge. Arriving at the right diagnosis is crucial because these two diseases differ in their prognosis and management. A high index of suspicion is therefore important so as not to miss the correct diagnosis. The diagnosis may be overlooked because the clinical presentation may not be typical of B-LBL or the blood counts do not show any abnormalities. In this report, we highlight one such case where the diagnosis of B-LBL was missed because of its atypical presentation.

Integrated sensing layer of bacterial cellulose and polyethyleneimine to achieve high sensitivity of ST-cut quartz surface acoustic wave formaldehyde gas sensor

Surface acoustic wave (SAW)-based formaldehyde gas sensor using bi-layer nanofilms of bacterial cellulose (BC) and polyethyleneimine (PEI) was developed on an ST-cut quartz substrate using sol-gel and spin coating processes. BC nanofilms significantly improve the sensitivity of PEI films to formaldehyde gas, and reduces response and recovery times. The BC films have superfine filamentary and fibrous network structures, which provide a large number of attachment sites for the PEI particles. Measurement results obtained using in situ diffuse reflectance Fourier transform infrared spectroscopy showed that the primary amino groups of PEI strongly adsorb formaldehyde molecules through nucleophilic reactions, thus resulting in a negative frequency shift of the SAW sensor due to the mass loading effect. In addition, experimental results showed that the frequency shifts of the SAW devices are determined by thickness of PEI film, concentration of formaldehyde and relative humidity. The PEI/BC sensor coated with three layers of PEI as the sensing layer showed the optimal sensing performance, which had a frequency shift of 35.6 kHz for 10 ppm formaldehyde gas, measured at room temperature and 30 % RH. The sensor also showed good selectivity and stability, with a low limit of detection down to 100 ppb.

Evaluation of coagulation factor activity and sterility of thawed fresh frozen plasma during storage up to 5 days at 4°C

INTRODUCTION

Fresh frozen plasma (FFP) is a blood component containing functional quantities of all coagulation factors stored at -18°C or below. FFP has to be thawed and transfused as soon as possible to prevent the loss of certain coagulation factor activities and to minimise microbial contamination.

MATERIALS AND METHODS

Thirty units of FFP kept at -20°C were thawed using a 37°C water bath and immediately sampled for baseline Factor II (FII), Factor VIII (FVIII) and fibrinogen activity levels and sterility testing. Each unit was then divided into two smaller bags (i.e. Bag I and Bag II) and kept at 4°C. At 6 hours and Day 3, representative samples were taken from Bag I for coagulation factor activity assays, while at Day 5 representative samples were taken from Bag II for coagulation factor activity assays and sterility testing.

RESULTS

FII activities at the four time points were 73.43%, 73.73%, 71% and 69.8%, respectively, while FVIII activities were 177.63%, 144.37%, 80.8% and 70.97%, respectively. Fibrinogen levels at the four time points were 3.24 g/L, 3.24 g/L, 3.21 g/L and 3.20 g/L, respectively. All samples were free from microbial contamination even at Day 5.

CONCLUSION

The mean reduction in FII and fibrinogen activities on Day 5 was 5% and 1%, respectively. However, FVIII activity declined significantly by approximately 60% at Day 5. Despite these reductions, thawed plasma stored for up to 5 days at 4°C is still suitable for use as the coagulation factor activity levels still exceed the minimum release criteria recommended in quality assurance regulations.

Convergences of Life Sciences and Engineering in Understanding and Treating Heart Failure

On March 1 and 2, 2018, the National Institutes of Health 2018 Progenitor Cell Translational Consortium, Cardiovascular Bioengineering Symposium, was held at the University of Alabama at Birmingham. Convergence of life sciences and engineering to advance the understanding and treatment of heart failure was the theme of the meeting. Over 150 attendees were present, and >40 scientists presented their latest work on engineering human functional myocardium for disease modeling, drug development, and heart failure research. The scientists, engineers, and physicians in the field of cardiovascular sciences met and discussed the most recent advances in their work and proposed future strategies for overcoming the major roadblocks of cardiovascular bioengineering and therapy. Particular emphasis was given for manipulation and using of stem/progenitor cells, biomaterials, and methods to provide molecular, chemical, and mechanical cues to cells to influence their identity and fate in vitro and in vivo. Collectively, these works are profoundly impacting and progressing toward deciphering the mechanisms and developing novel treatments for left ventricular dysfunction of failing hearts. Here, we present some important perspectives that emerged from this meeting.

An Audit on Overnight Transfusion Practice in A Teaching Hospital in Malaysia

INTRODUCTION

Overnight transfusion (OT) is the blood transfusion taking place from 9pm to 8am. During this period, patients are exposed to increased risk of errors. This cross-sectional study aims to determine the incidence and practice of OT in Universiti Kebangsaan Malaysia Medical Centre.

MATERIALS & METHODS

Data from all OT in June and mid-July 2017 were collected from recipients' cards, transfusion request forms and patient's case files, regarding discipline involved, indications, time intervals from request of blood transfusion to the completion of OT on patients, monitoring of patients and adverse reactions.

RESULTS

A total of 1285 transfusion cases were identified during the study period. 216 (16.8%) cases were OT while the 1069 (83.2%) cases were non-OT. Surgery discipline has the highest (30.1%) OT. The indications of OT were acute clinical need: 82.9%, less acute clinical need: 13.9% and no clinical need: 3.2%. A huge delay (average: 5 hours 40 minutes) in starting transfusion after grouping and crossmatching (GXM) completion was noted. Besides, 25.9% cases took <4 hours to complete OT; 83.4% cases did not have proper transfusion monitoring and three transfusion reactions were reported.

DISCUSSION

Although most of the OT cases had appropriate clinical indications, the transfusion can be commenced earlier at day time rather than overnight. Cases without absolute indication should avoid OT. The poor monitoring of patient during OT had posed risks to patients' life if an adverse transfusion reaction happened. The major reason for OTs was a huge delay in starting transfusion after the GXM completion. The contravention of 4-hour infusion rule increased the patients' risk of developing bacterial sepsis. The practice of OT should be discouraged wherever possible except for clinically indicated cases.

Enhancer of zeste homolog 2 (EZH2) regulates adipocyte lipid metabolism independent of adipogenic differentiation: Role of apolipoprotein E

Enhancer of zeste homolog 2 (EZH2), an epigenetic regulator that plays a key role in cell differentiation and oncogenesis, was reported to promote adipogenic differentiation in vitro by catalyzing trimethylation of histone 3 lysine 27. However, inhibition of EZH2 induced lipid accumulation in certain cancer and hepatocyte cell lines. To address this discrepancy, we investigated the role of EZH2 in adipogenic differentiation and lipid metabolism using primary human and mouse preadipocytes and adipose-specific EZH2 knockout (KO) mice. We found that the EZH2-selective inhibitor GSK126 induced lipid accumulation in human adipocytes, without altering adipocyte differentiation marker gene expression. Moreover, adipocyte-specific EZH2 KO mice, generated by crossing EZH2 floxed mice with adiponectin-Cre mice, displayed significantly increased body weight, adipose tissue mass, and adipocyte cell size and reduced very low-density lipoprotein (VLDL) levels, as compared with littermate controls. These phenotypic alterations could not be explained by differences in feeding behavior, locomotor activity, metabolic energy expenditure, or adipose lipolysis. In addition, human adipocytes treated with either GSK126 or vehicle exhibited comparable rates of glucose-stimulated triglyceride accumulation and fatty acid uptake. Mechanistically, lipid accumulation induced by GSK126 in adipocytes was lipoprotein-dependent, and EZH2 inhibition or gene deletion promoted lipoprotein-dependent lipid uptake in vitro concomitant with up-regulated apolipoprotein E (ApoE) gene expression. Deletion of ApoE blocked the effects of GSK126 to promote lipoprotein-dependent lipid uptake in murine adipocytes. Collectively, these results indicate that EZH2 inhibition promotes lipoprotein-dependent lipid accumulation via inducing ApoE expression in adipocytes, suggesting a novel mechanism of lipid regulation by EZH2.

[Application of self-made stretch pants in patients with burn in special sites]

The change and fixation of dressing are difficult in patients with burn in special sites of perineum, buttocks, and bilateral thighs. Therefore, we designed and made stretch pants by ourselves for dressing fixation after dressing change in patients with burns in abdomen, buttocks, and bilateral thighs. The stretch pants are made by cutting and splicing elastic fabric according to perimeters of abdomen and legs. The stretch pants are used after wound dressing change, which can fix the dressing stably, accelerate wound healing, and reduce the medical workers' labor intensity of dressing change and economic burden of patients. And patients can walk out of bed early. It's especially suitable for dressing fixation of infants and other patients who are unwilling to cooperate. Besides, it's easy to make with low cost and suitable for clinical promotion.

[A family with Allan-Herndon-Dudley syndrome due to SLC16A2 gene mutation]

Objective: To report a family diagnosed with Allan-Herndon-Dudley syndrome (AHDS) due to SLC16A2 gene mutation and to summarize the phenotypes, genotypes, diagnosis, treatment, and prognosis. Methods: The clinical features of a family of AHDS diagnosed in Xiangya Hospital of Central South University in November 2017 were analyzed. Related literature was searched at Online Mendelian Inheritance in Man (OMIM), PubMed, CNKI and Wanfang database (from the establishment of databases to June 2018) by using "Allan-Herndon-Dudley syndrome" , and "AHDS" as keywords and the case reports from April 2013 to June 2018 were reviewed. Results: The proband was a boy aged 8 months who presented with global developmental retardation, inability to hold up the head, disability to sit independently or grab, no language development, elongated face, big ears, esotropia, scoliosis, hypotonia in the trunk, hypertonia in extremities, and hyperreflexia. Brain magnetic resonance imaging (MRI) showed widening of the extracerebral space and delayed myelination. Thyroid function tests revealed increased FT3, decreased FT4 and normal TSH. Whole exome sequencing (WES) revealed the SLC16A2 gene c.431-1 (IVS1) G>C hemizygous mutation. The infant's mother and grandmother are carriers, but whose father had no related mutation. One uncle from maternal side had severe psychomotor retardation as well as dystonia and died at one year of age with unknown etiology. A total of 97 articles were retrieved in which 19 case reports were reviewed. Forty-two cases (22 from 8 families and 20 sporadic) were reported. Among these 42 cases (all males), all of them presented with moderate to severe cognitive dysfunction, 15 with seizures; 36 were bedridden, only 4 could walk; 31 had no language development, 2 could speak sentences, 4 could speak few words, 1 had babbling sounds. Furthermore,16 had microcephaly, 18 had facial dysmorphism, 6 had esotropia, 2 had hearing loss,14 had scoliosis, 11 had joint contracture, 30 had low body weight/muscle wasting, 37 had hypotonia in trunk or extremities, 32 had progressive spastic paraplegia or hypertonia. In terms of thyroid function, 33 had abnormal results, within whom 30 had increased T3, 25 had decreased T4 and 3 had increased TSH. Brain MRI showed delayed myelination in 22 cases, within which one normalized with development. Genetic tests showed that 31 had missense mutation (14 sporadic), 5 had deletion mutation (3 sporadic, and 1 due to frameshift mutation), 5 had insertion mutation (2 sporadic), and 1 had repeated mutation. The prognosis was poor as patients often died of recurrent respiratory tract infection. Conclusions: The main clinical manifestations of AHDS are severe global developmental retardation, hypotonia, spastic paraplegia, abnormal serum levels of thyroid hormone and delayed brain myelination. SLC16A2 c. 431-1 (IVS1) G > C mutation is accountable for this disease.

Myelodysplastic syndrome with fibrosis and complex karyotype arising in a patient with essential thrombocythaemia

INTRODUCTION

Essential thrombocythaemia (ET) is a chronic myeloproliferative neoplasm (MPN) characterised by persistent thombocytosis. It is an indolent disorder but transformation to myelofibrosis (MF), acute myeloid leukaemia (AML) or myelodyplastic syndrome (MDS) has been reported.

CASE REPORT

We described a patient with ET whose disease evolved into MDS with fibrosis and complex karyotype after 15 years of stable disease. She was asymptomatic and was on hydroxyurea (HU) treatment until recently when she presented with worsening anaemia. Physical examination showed mild splenomegaly. Full blood picture showed leukoerythroblastic picture with presence of 3% circulating blasts and background of dysplastic features such as hypogranular cytoplasm and nuclear hyposegmentation of neutrophils. The bone marrow aspiration was haemodiluted but revealed presence of 6% blast cells, trilineage dysplasia and predominant erythroid precursors (60%). Trephine biopsy showed no excess of blast cells and normal quantity of erythroid precursors, but there was increased in fibrosis (WHO grade 2) and presence of dysmegakaryopoeisis such as nuclear hypolobation, multinucleation and micromegakaryocytes. Cytogenetic study showed complex karyotype; monosomy of chromosome 2, chromosome 5, chromosome 18 and presence of a marker chromosome (42~44, XX,-2,-5,-18,+mar). Fluorescence in situ hybridisation (FISH) showed 5q deletion (CSF1R and EGR1).

CONCLUSION

The findings were consistent with transformation of ET to MDS with fibrosis and complex karyotype. ET progression to MDS is considered rare. The presence of complex karyotype and fibrosis in MDS are associated with unfavourable outcome.

Multiple strains and polar states in PbZr0.52Ti0.48O3/PbTiO3 superlattices revealed by aberration-corrected HAADF-STEM imaging

Tuning multiple strain and polar states of ferroelectrics by using strain engineering is an essential approach for designing multifunctional electric devices such as multiple state memories. However, integrating multiple strain states is still a challenge, and in addition, revealing such strains and the resultant polar behaviors on the atomic level remains difficult. In this work we prepare PbZr_0.52Ti_0.48O₃/PbTiO₃ (PZT/PTO) superlattices on SrRuO₃-buffered SrTiO₃(001) substrates. Aberration-corrected high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) reveals that the superlattice is coherent in both c (out-of-plane polar direction) and a (in-plane polar direction) domains. We find that the strain states of both PZT and PTO in c and a domains are variant, leading to four special strain states. For example, the tetragonality for PTO in c and a domains is 1.061 and 1.045, respectively. In contrast, PZT in c domains displays a tetragonality as giant as 1.107, which corresponds to 110 µC cm^-2 spontaneous polarization, much larger than the bulk PZT; while PZT in a domains exhibits 1.010 tetragonality with about 70 µC cm^-2 polarization. This study reveals a practical way to integrate multiple strain states and enhanced polarizations in ferroelectric films, which could be used as multifunctional electric elements.

The crucial role of molecular testing to facilitate the diagnosis of pneumocystis pneumonia during pregnancy

Pneumocystis pneumonia is an important human immunodeficiency virus (HIV)-associated opportunistic infection, and especially so in pregnant HIV-positive patients. We report a case of a 40-year-old woman in her first trimester of pregnancy who initially presented with acute gastroenteritis symptoms but due to a history of high-risk behaviour and the observation of oral thrush, she was worked up for HIV infection. Her retroviral status was positive and her CD4+ T cell count was only 8 cells/µL. She was also worked up for pneumocystis pneumonia due to the presence of mild resting tachypnoea and a notable drop in oxygen saturation (from 100% to 88%) following brief ambulation. Her chest radiograph revealed bilaterally symmetrical lower zone reticular opacities and Giemsa staining of her bronchoalveolar lavage (BAL) was negative for Pneumocystis jirovecii cysts. However, real-time P. jirovecii polymerase chain reaction (PCR) testing on the same BAL specimen revealed the presence of the organism. A course of oral co-trimoxazole plus prednisolone was commenced and her clinical condition improved.

Emerging role of extracellular vesicles in musculoskeletal diseases

Research into the biology of extracellular vesicles (EVs), including exosomes and microvesicles, has expanded significantly with advances in EV isolation techniques, a better understanding of the surface markers that characterize exosomes and microvesicles, and greater information derived from -omics approaches on the proteins, lipids, mRNAs, and microRNAs (miRNAs) transported by EVs. We have recently discovered a role for exosome-derived miRNAs in age-related bone loss and osteoarthritis, two conditions that impose a significant public health burden on the aging global population. Previous work has also revealed multiple roles for EVs and their miRNAs in muscle regeneration and congenital myopathies. Thus, EVs appear to be involved in a number of degenerative conditions that impact the musculoskeletal system, indicating that the musculoskeletal system is an excellent model for investigating the role of EVs in tissue maintenance and repair. This review highlights the role of EVs in bone, skeletal muscle, and joint health, including both normal tissue metabolism as well as tissue injury repair and regeneration. A consistent theme that emerges from study of musculoskeletal EVs is that various miRNAs appear to mediate a number of key pathological processes. These findings point to a potential therapeutic opportunity to target EV-derived miRNAs as a strategy for improving musculoskeletal function.

Designing of metallic nanocrystals embedded in non-stoichiometric perovskite nanomaterial and its surface-electronic characteristics

Engineering of novel functional nanocomposite as like as the metallic nanocrystals supported non-stoichiometric perovskite nanomaterial in controlled parameters (size, shape and ratio of chemical characteristics) is a challengeable task. In this context, we present a facile route to fabricate and study its physicochemical property at real time mode in this report. Nanoscale pure Pb crystals surfaced on non-stoichiometric A-site deficient Pb_1-xTiO_3-y nanoparticle were fabricated when a precursor lead titanate (PbTiO₃) nanoparticle was exposed to an electron beam irradiation (EBI) in a transmission electron microscope (TEM) at ambient temperature. In the state of the art, the chemical states and electronic structure of non-irradiated and irradiated PbTiO₃ were studied by X-ray photoelectron spectroscopy (XPS). Electron bombardment resulted in a new visible feature at low binding energy in the Pb 4f core level, while Ti 2p and O 1s line shape showed slight changes. The Fermi level of the corresponding materials was determined to be 1.65 ± 0.1 eV and 2.05 ± 0.1 eV above the valence band maximum, respectively. The normal, weakly p-type PTO exhibits peculiar n-type feature after EBI process (The Fermi level moves near to the conduction band). A feasible mechanism is proposed involving the electron-stimulated local bond-breaking phenomenon in PbTiO₃.

Targeted ultrasound molecular imaging in mouse atherosclerotic plaque model

This study aims to assess the early diagnosis of mouse atherosclerotic plaque through targeted ultrasound molecular imaging. Forty Apolipoprotein E-deficient (ApoE-/-) mice and 40 C57BL/6 wild type mice were randomly divided into 4 groups, 20 mice per group. Mice included in the study group were fed with high cholesterol diet for 20 weeks, after which the targeted ultrasound microbubbles were prepared. The mice with atherosclerotic plaque were studied with targeted ultrasound molecular imaging in comparison with red oil O staining. The results of targeted ultrasound molecular imaging of atherosclerotic plaque indicate that the GP Ib and GP IIb/IIIa are viable biomarkers for early diagnosis of vulnerable atherosclerotic plaque. The targeted ultrasound molecular imaging is worth studying in order to identify the atherosclerotic progress as a noninvasive effective identification method which could be used widely.

Giant linear strain gradient with extremely low elastic energy in a perovskite nanostructure array

Although elastic strains, particularly inhomogeneous strains, are able to tune, enhance or create novel properties of some nanoscale functional materials, potential devices dominated by inhomogeneous strains have not been achieved so far. Here we report a fabrication of inhomogeneous strains with a linear gradient as giant as 10⁶ per metre, featuring an extremely lower elastic energy cost compared with a uniformly strained state. The present strain gradient, resulting from the disclinations in the BiFeO₃ nanostructures array grown on LaAlO₃ substrates via a high deposition flux, induces a polarization of several microcoulomb per square centimetre. It leads to a large built-in electric field of several megavoltage per metre, and gives rise to a large enhancement of solar absorption. Our results indicate that it is possible to build up large-scale strain-dominated nanostructures with exotic properties, which in turn could be useful in the development of novel devices for electromechanical and photoelectric applications.

[Clinical effects of Joint Active System on the treatment of joint dysfunction after deep burn]

Objective: To observe the clinical effects of the Joint Active System on the treatment of joint dysfunction after deep burn. Methods: Twenty-two patients with joint dysfunction after deep burn were hospitalized in Institute of Burns of Tongren Hospital of Wuhan University & Wuhan Third Hospital from January 2015 to October 2016, involving 18 elbow joints with flexion disorder, 10 wrist joints with dorsal extension disorder, and 12 ankle joints with dorsal extension disorder. They were treated with the elbow joint activity training device, the wrist joint activity training device, and the ankle joint activity training device of the Joint Active System, respectively. The treatment was carried out 3 times each day with interval of 6 h, 30 minutes each time, and it lasted for four to seven months, with one month as a course of treatment. Before treatment and 1, 2, 3, 4 month (s) after, active motion range of each joint was measured by joint goniometer. Function improvement of each joint was evaluated, and the total effective ratio was calculated 4 months after treatment. Satisfaction degree of patients was assessed by the modified Likert Scale 1, 2, 3, 4 month (s) after treatment. Data were processed with one-way analysis of variance for repeated measurement and LSD test. Results: Before treatment and 1, 2, 3, 4 month (s) after, flexion active motion range of elbow joints were (61±23), (78±22), (89±20), (96±20), and (103±19)°; dorsal extension active motion range of wrist joints were (23±7), (31±6), (38±9), (44±5), and (49±8)°; dorsal extension active motion range of ankle joints were (-31±12), (-23±10), (-16±7), (-12±6), and (-8±4)°, respectively. The active motion range of each joint was obviously higher 1, 2, 3, 4 month (s) after treatment than the previous time point of the same joint (with P values below 0.01). Four months after treatment, the total effective ratios of function improvement of elbow joints, wrist joints, and ankle joints were 5/6, 9/10, and 2/3, respectively. Scores of satisfaction degree of the patients 1, 2, 3, 4 month (s) after treatment were (1.3±0.7), (2.2±1.0), (2.8±0.8), and (3.3±0.6) points, respectively. Scores of satisfaction degree of the patients were obviously higher 2, 3, 4 months after treatment than the previous time point (with P values below 0.05). Conclusions: Joint Active System can improve the active range of motion of each joint obviously in treating joint dysfunction after deep burn, with total effective ratio of function improvement of each joint surpassing 0.66, and the majority of patients are quite satisfied with the curative effects.

A novel role for the Wnt inhibitor APCDD1 in adipocyte differentiation: Implications for diet-induced obesity

Impaired adipogenic differentiation during diet-induced obesity (DIO) promotes adipocyte hypertrophy and inflammation, thereby contributing to metabolic disease. Adenomatosis polyposis coli down-regulated 1 (APCDD1) has recently been identified as an inhibitor of Wnt signaling, a key regulator of adipogenic differentiation. Here we report a novel role for APCDD1 in adipogenic differentiation via repression of Wnt signaling and an epigenetic linkage between miR-130 and APCDD1 in DIO. APCDD1 expression was significantly up-regulated in mature adipocytes compared with undifferentiated preadipocytes in both human and mouse subcutaneous adipose tissues. siRNA-based silencing of APCDD1 in 3T3-L1 preadipocytes markedly increased the expression of Wnt signaling proteins (Wnt3a, Wnt5a, Wnt10b, LRP5, and β-catenin) and inhibited the expression of adipocyte differentiation markers (CCAAT/enhancer-binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ)) and lipid droplet accumulation, whereas adenovirus-mediated overexpression of APCDD1 enhanced adipogenic differentiation. Notably, DIO mice exhibited reduced APCDD1 expression and increased Wnt expression in both subcutaneous and visceral adipose tissues and impaired adipogenic differentiation in vitro Mechanistically, we found that miR-130, whose expression is up-regulated in adipose tissues of DIO mice, could directly target the 3'-untranslated region of the APCDD1 gene. Furthermore, transfection of an miR-130 inhibitor in preadipocytes enhanced, whereas an miR-130 mimic blunted, adipogenic differentiation, suggesting that miR-130 contributes to impaired adipogenic differentiation during DIO by repressing APCDD1 expression. Finally, human subcutaneous adipose tissues isolated from obese individuals exhibited reduced expression of APCDD1, C/EBPα, and PPARγ compared with those from non-obese subjects. Taken together, these novel findings suggest that APCDD1 positively regulates adipogenic differentiation and that its down-regulation by miR-130 during DIO may contribute to impaired adipogenic differentiation and obesity-related metabolic disease.

Dismal outcome of therapy-related myeloid neoplasm associated with complex aberrant karyotypes and monosomal karyotype: a case report

INTRODUCTION

Individuals who are exposed to cytotoxic agents are at risk of developing therapyrelated myeloid neoplasms (t-MN). Cytogenetic findings of a neoplasm play an important role in stratifying patients into different risk groups and thus predict the response to treatment and overall survival.

CASE REPORT

A 59-year-old man was diagnosed with acute promyelocytic leukaemia. Following this, he underwent all-trans retinoic acid (ATRA) based chemotherapy and achieved remission. Four years later, the disease relapsed and he was given idarubicin, mitoxantrone and ATRA followed by maintenance chemotherapy (ATRA, mercaptopurine and methotrexate). He achieved a second remission for the next 11 years. During a follow-up later, his full blood picture showed leucocytosis, anaemia and leucoerythroblastic picture. Bone marrow examination showed hypercellular marrow with trilineage dysplasia, 3% blasts but no abnormal promyelocyte. Fluorescence in-situ hybridisation (FISH) study of the PML/RARA gene was negative. Karyotyping result revealed complex abnormalities and monosomal karyotype (MK). A diagnosis of therapy-related myelodysplastic syndrome/myeloproliferative neoplasm with unfavourable karyotypes and MK was made. The disease progressed rapidly and transformed into therapy-related acute myeloid leukaemia in less than four months, complicated with severe pneumonia. Despite aggressive treatment with antibiotics and chemotherapy, the patient succumbed to the illness two weeks after the diagnosis.

DISCUSSION AND CONCLUSION

Diagnosis of t-MN should be suspected in patients with a history of receiving cytotoxic agents. Karyotyping analysis is crucial for risk stratification as MK in addition to complex aberrant karyotypes predicts unfavourable outcome. Further studies are required to address the optimal management for patients with t-MN.

Misfit Strain Relaxation of Ferroelectric PbTiO3/LaAlO3 (111) Thin Film System

Ferroelectric thin films grown on high index substrates show unusual structural and switching dynamics due to their special strain states. Understanding the misfit relaxation behavior is crucial to facilitate the high index thin film growth with improved quality. In this paper, ferroelectric PbTiO₃ thin films were grown on LaAlO₃ (111) substrates by pulsed laser deposition technique. The microstructures were investigated by combinations of conventional and aberration-corrected transmission electron microscopy. Diffraction contrast analysis and high resolution imaging reveal that high density interfacial dislocations were distributed at the interfaces. These dislocations have mixed character with Burgers vectors of a <110> and line directions of <112>. The edge components of the dislocations, with the Burgers vectors parallel to the interface, accommodate the lattice mismatch and are the main contributor to the misfit relaxation of this system. The formation mechanism of these dislocations is proposed and discussed to elucidate the novel mismatch relaxation behavior of <111> oriented perovskite films.

Perceptions of public attitudes towards persons with mental illness in Beijing, China: results from a representative survey

OBJECTIVES

Many studies have examined the general public's attitudes towards people with mental illness, but such studies are scarce in China. This study examined the perceptions of the Beijing population regarding their society's prevalent attitudes towards people with mental illness.

METHODS

A total of 5000 individuals aged 18 or above living in Beijing were selected using a multistage, stratified, cluster and random sampling method. This was followed by a face-to-face interview which used a standardized questionnaire asking about societal attitudes towards individuals with mental illness.

RESULTS

4602 out of 5000 eligible individuals met the inclusion criteria and participated in the interview. 4596 questionnaires were deemed valid and included in the analyses. A large proportion of respondents believed that most individuals within their society held negative attitudes and had a strong desire to distance themselves from people with mental illness. Respondents aged 60 or older, who lived farther to downtown Beijing, or with higher education tended to believe that most individuals have relatively positive and tolerant attitudes towards people with mental illness.

CONCLUSIONS

Many people in Beijing perceive that most members of their society have negative beliefs towards people with mental illness. Further efforts are needed to determine if these perceptions are accurate and to reduce the stigma that is reinforced by these perceptions.

Electrical stimulation to optimize cardioprotective exosomes from cardiac stem cells

Injured or ischemic cardiac tissue has limited intrinsic capacity for regeneration. While stem cell transplantation is a promising approach to stimulating cardiac repair, its success in humans has thus far been limited. Harnessing the therapeutic benefits of stem cells requires a better understanding of their mechanisms of action and methods to optimize their function. Cardiac stem cells (CSC) represent a particularly effective cellular source for cardiac repair, and pre-conditioning CSC with electrical stimulation (EleS) was demonstrated to further enhance their function, although the mechanisms are unknown. Recent studies suggest that transplanted stem cells primarily exert their effects through communicating with endogenous tissues via the release of exosomes containing cardioprotective molecules such as miRNAs, which upon uptake by recipient cells may stimulate survival, proliferation, and angiogenesis. Exosomes are also effective therapeutic agents in isolation and may provide a feasible alternative to stem cell transplantation. We hypothesize that EleS enhances CSC-mediated cardiac repair through its beneficial effects on production of cardioprotective exosomes. Moreover, we hypothesize that the beneficial effects of biventricular pacing in patients with heart failure may in part result from EleS-induced preconditioning of endogenous CSC to promote cardiac repair. With future research, our hypothesis may provide applications to optimize stem cell therapy and augment current pacing protocols, which may significantly advance the treatment of patients with heart disease.

Label-free aptasensor for adenosine deaminase sensing based on fluorescence turn-on

A label-free and fluorescence turn-on aptamer biosensor has been developed for the detection of adenosine deaminase (ADA) activity with simplicity and selectivity. Adenosine aptamer will form a tight stem-loop structure upon binding with adenosine. In the absence of ADA, only a small quantity of picagreen intercalates into the stem section of aptamer, resulting in a low fluorescence of picagreen when excited at 490 nm. Interestingly, after the addition of ADA, adenosine is hydrolyzed to inosine, and the released aptamer forms double-stranded DNA (dsDNA) with its complementary single-stranded DNAc, followed by the intercalation of picagreen to dsDNA. When the solution is excited, picagreen emits strong green fluorescence. The increased fluorescence intensity of picagreen is dependent on the concentration of ADA. The detection limit of the ADA is determined to be 2 U L(-1), which is lower than ADA cutoff value (4 U L(-1)) in the clinical requirement and more sensitive than most of the reported methods. Compared to other previous ADA sensors, the assay is not only label-free but also a turn-on signal, and possesses properties of lower cost and simpler detection system. Furthermore, this label-free strategy is also applicable to the assay of other enzymes and screening of corresponding inhibitors.

Removal of titanium dioxide nanoparticles by coagulation: effects of coagulants, typical ions, alkalinity and natural organic matters

To investigate the possibility of removing titanium dioxide nanoparticles (TiO2 NPs) from water by coagulation, as well as to find the optimal coagulant and experimental conditions for TiO2 NP removal, four types of coagulant were adopted: polyferric sulfate (PFS), ferric chloride (FeCl3), polyaluminum chloride (PACl), and alum (Al2(SO4)3). It was found that the removal of TiO2 NPs by coagulation was affected by ionic strength, alkalinity, as well as types and dosages of coagulants. PFS and FeCl3 achieved much higher removal efficiency of TiO2 NPs than PACl and Al2(SO4)3 did. For 30 mg/L TiO2 NPs, a dosage of 0.3 mM PFS (as Fe) achieved 84% removal after coagulation followed by 30 min settlement. Optimal ionic strength (0.1 M NaCl or 0.03 M CaCl2) is of vital importance for the performance of PFS. Na2SO4 is unfavorable for the performance of PFS. Optimal alkalinity (0.01-0.03 M NaHCO3) is necessary for FeCl3 to remove TiO2 NPs. Natural organic matter, as represented by humic acid (HA) up to 11 mg/L, reduces the removal of TiO2 NPs by coagulation. These findings indicate that coagulation is a good option for the removal of TiO2 NPs from water, and more attention should be paid to the effects of water quality when using coagulation to remove TiO2 NPs from aqueous matrices. This provides a possible solution to alleviate the potential hazard caused by TiO2 NPs.

Molecular cloning and characterization of gene coding for γ-tocopherol methyltransferase from lettuce (Lactuca sativa)

γ-tocopherol methyltransferase is an important rate-limiting enzyme involved in tocopherol biosynthesis. The full-length cDNA encoding γ-tocopherol methyltransferase (designated as LsTMT) was cloned from Lactuca sativa for the first time by rapid amplification of cDNA ends and characterized by means of quantitative RT-PCR. The full-length cDNA of LsTMT was 1131 bp, with an open reading frame of 897 bp encoding a γ-tocopherol methyltransferase protein of 298 amino acids, with a calculated molecular mass of 33.06 kDa and an isoelectric point of 5.86. Comparative analysis revealed that LsTMT has a close similarity with γ-TMTs from other plant species. Bioinformatic analysis indicated that LsTMT shares a common evolutionary origin based on sequence similarity and has the closest relationship to γ-TMT from the sunflower, Helianthus annuus. Based on quantitative RT-PCR analysis, we found that expression of LsTMT is induced and strengthened by oxidative stresses such as strong light and drought. The cloning and characterization of LsTMT will be helpful to further understanding its role in the tocopherol biosynthesis pathway. We consider it to be a candidate gene for metabolic engineering of vitamin E in vegetable crops.

Combinatorial treatment of bone marrow stem cells and stromal cell-derived factor 1 improves glycemia and insulin production in diabetic mice

Transdifferentiation of stem cells into insulin-producing cells for the treatment of diabetes have shown promising but inconsistent results. We examined the potential for attracting bone marrow stem cells (BMSCs) to the pancreas using a chemokine, stromal cell-derived factor 1 (SDF-1). SDF-1 treatment markedly increased the number of GFP labeled BMSCs in the pancreas, but surprisingly, the majority was observed in liver. The liver cells had typical pancreatic endocrine cell gene expression including insulin I, insulin II, PDX-1, somatostatin, and glucagon. Combined treatment with SDF-1 and BMSC transplant reduced hyperglycemia and prolonged the long-term survival of diabetic mice, and a sub group had complete normoglycemia (<150 mg/dl), restored blood insulin levels, and normal glucose tolerance. Our results suggest that SDF-1 could potentially be used to improve the homing of stem cells and β-cell regeneration. The mechanism appears to involve an increase in insulin producing cells mainly in the liver.

Molecular cloning and characterization of a tocopherol cyclase gene from Lactuca sativa (Asteraceae)

Tocopherol cyclase is a rate-limiting enzyme involved in tocopherol biosynthesis. The full-length cDNA encoding tocopherol cyclase (designated as LsTC) was cloned from lettuce (Lactuca sativa) for the first time by rapid amplification of cDNA ends (RACE) and characterized by means of quantitative RT-PCR. The full-length cDNA of LsTC was 1675 bp, with an open reading frame of 1521 bp, encoding a tocopherol cyclase protein of 506 amino acids, with a calculated molecular mass of 56.76 kD and an isoelectric point of 6.49. Comparative analysis revealed that LsTC has a close similarity with tocopherol cyclases from other plant species. Bioinformatic analysis indicated that LsTC shares a common evolutionary origin based on sequence and has the closest relationship to tocopherol cyclase from Helianthus annuus. Quantitative RT-PCR analysis suggested that expression of LsTC is induced and strengthened by oxidative stresses, such as strong light and drought. This cloning and characterization of LsTC will be helpful for further understanding of its role in the tocopherol biosynthesis pathway and provide a candidate gene for metabolic engineering of vitamin E.

CXCR4-mediated bone marrow progenitor cell maintenance and mobilization are modulated by c-kit activity

RATIONALE

The mobilization of bone marrow (BM) progenitor cells (PCs) is largely governed by interactions between stromal cell-derived factor (SDF)-1 and CXC chemokine receptor (CXCR)4. Ischemic injury disrupts the SDF-1-CXCR4 interaction and releases BM PCs into the peripheral circulation, where the mobilized cells are recruited to the injured tissue and contribute to vessel growth. BM PCs can also be mobilized by the pharmacological CXCR4 antagonist AMD3100, but the other components of the SDF-1-CXCR4 signaling pathway are largely unknown. c-kit, a membrane-bound tyrosine kinase and the receptor for stem cell factor, has also been shown to play a critical role in BM PC mobilization and ischemic tissue repair.

OBJECTIVE

To investigate the functional interaction between SDF-1-CXCR4 signaling and c-kit activity in BM PC mobilization.

METHODS AND RESULTS

AMD3100 administration failed to mobilize BM PCs in mice defective in c-kit kinase activity or in mice transplanted with BM cells that expressed a constitutively active c-kit mutant. Furthermore, BM levels of phosphorylated (phospho)-c-kit declined after AMD3100 administration and after CXCR4 deletion. In cells adhering to culture plates coated with vascular cell adhesion molecule 1, SDF-1 and stem cell factor increased phospho-c-kit levels, and AMD3100 treatment suppressed SDF-1-induced, but not SCF-induced, c-kit phosphorylation. SDF-1-induced c-kit phosphorylation also required the activation of Src nonreceptor tyrosine kinase: pretreatment of cells with a selective Src inhibitor blocked both c-kit phosphorylation and the interaction between c-kit and phospho-Src.

CONCLUSIONS

These findings indicate that the regulation of BM PC trafficking by SDF-1 and CXCR4 is dependent on Src-mediated c-kit phosphorylation.

Regulation of vascular contractility and blood pressure by the E2F2 transcription factor

BACKGROUND

Recent studies have identified a polymorphism in the endothelin-converting enzyme (ECE)-1b promoter (-338C/A) that is strongly associated with hypertension in women. The polymorphism is located in a consensus binding sequence for the E2F family of transcription factors. E2F proteins are crucially involved in cell-cycle regulation, but their roles in cardiovascular function are poorly understood. Here, we investigated the potential role of E2F2 in blood pressure regulation.

METHODS AND RESULTS

Tail-cuff measurements of systolic and diastolic blood pressures were significantly higher in E2F2-null (E2F2(-/-)) mice than in their wild-type littermates, and in ex vivo ring assays, aortas from the E2F2(-/-) mice exhibited significantly greater contractility in response to big endothelin-1. Big endothelin-1 is activated by ECE-1, and mRNA levels of ECE-1b, the repressive ECE-1 isoform, were significantly lower in E2F2(-/-) mice than in wild-type mice. In endothelial cells, chromatin immunoprecipitation assays confirmed that E2F2 binds the ECE-1b promoter, and promoter-reporter assays indicated that E2F2 activates ECE-1b transcription. Furthermore, loss or downregulation of E2F2 led to a decline in ECE-1b levels, to higher levels of the membranous ECE-1 isoforms (ie, ECE-1a, -1c, and -1d), and to deregulated ECE-1 activity. Finally, Sam68 coimmunoprecipitated with E2F2, occupied the ECE-1b promoter (chromatin immunoprecipitation), and repressed E2F2-mediated ECE-1b promoter activity (promoter-reporter assays).

CONCLUSIONS

Our results identify a cell-cycle-independent mechanism by which E2F2 regulates endothelial function, arterial contractility, and blood pressure.

Hypoxic preconditioning enhances the benefit of cardiac progenitor cell therapy for treatment of myocardial infarction by inducing CXCR4 expression

Myocardial infarction rapidly depletes the endogenous cardiac progenitor cell pool, and the inefficient recruitment of exogenously administered progenitor cells limits the effectiveness of cardiac cell therapy. Recent reports indicate that interactions between the CXC chemokine stromal cell-derived factor 1 and its receptor CXC chemokine receptor 4 (CXCR4) critically mediate the ischemia-induced recruitment of bone marrow-derived circulating stem/progenitor cells, but the expression of CXCR4 in cardiac progenitor cells is very low. Here, we studied the influence of hypoxia on CXCR4 expression in cardiac progenitor cells, on the recruitment of intravenously administered cells to ischemic heart tissue, and on the preservation of heart function in a murine myocardial infarction model. We found that hypoxic preconditioning increased CXCR4 expression in CLK (cardiosphere-derived, Lin(-)c-kit(+) progenitor) cells and markedly augmented CLK cell migration (in vitro) and recruitment (in vivo) to the ischemic myocardium. Four weeks after surgically induced myocardial infarction, infarct size and heart function were significantly better in mice administered hypoxia-preconditioned CLK cells than in mice treated with cells cultured under normoxic conditions. Furthermore, these effects were largely abolished by the addition of a CXCR4 inhibitor, indicating that the benefits of hypoxic preconditioning are mediated by the stromal cell-derived factor 1/CXCR4 axis, and that therapies targeting this axis may enhance cardiac-progenitor cell-based regenerative therapy.

Stem cell therapy for heart failure: the science and current progress

Cell therapy, particularly with stem cells, has created great interest as a solution to the fact that there are limited treatments for postischemic heart disease and none that can regenerate damaged heart cells to strengthen cardiac performance. From the first efforts with myoblasts to recent clinical trials with bone marrow-derived stem cells, early reports of cell therapy suggest improvement in cardiac performance as well as other clinical end points. Based on these exciting but tentative results, other stem cell types are being explored for their particular advantages as a source of adult stem cells. Autologous adipose-derived stem cells are multilinear and can be obtained relatively easily in large quantities from patients; cardiac-derived stem cells are highly appropriate for engraftment in their natural niche, the heart. Human umbilical cord blood cells are potentially forever young and allogenic adult mesenchymal stem cells appear not to evoke the graft versus host reaction. Human embryonic stem cells are effective and can be scaled up for supply purposes. The recent discovery of induced pluripotentcy in human adult stem cells, with only three transcription factor genes, opens a whole new approach to making autologous human pluripotent stem cells from skin or other available tissues. Despite the excitement, stem cells may have to be genetically modified with heme oxygenase, Akt or other genes to survive transplantation in a hypoxic environment. Homing factors and hormones secreted from transplanted stem cells may be more important than cells if they provide the necessary stimulus to trigger cardiac regrowth to replace scar tissue. As we await results from larger and more prolonged clinical trials, the science of stem cell therapy in cardiac disease keeps progressing.

Genetic modification of stem cells for transplantation

Gene modification of cells prior to their transplantation, especially stem cells, enhances their survival and increases their function in cell therapy. Like the Trojan horse, the gene-modified cell has to gain entrance inside the host's walls and survive and deliver its transgene products. Using cellular, molecular and gene manipulation techniques the transplanted cell can be protected in a hostile environment from immune rejection, inflammation, hypoxia and apoptosis. Genetic engineering to modify cells involves constructing modules of functional gene sequences. They can be simple reporter genes or complex cassettes with gene switches, cell specific promoters and multiple transgenes. We discuss methods to deliver and construct gene cassettes with viral and non-viral delivery, siRNA, and conditional Cre/Lox P. We review the current uses of gene-modified stem cells in cardiovascular disease, diabetes, neurological diseases, (including Parkinson's, Alzheimer's and spinal cord injury repair), bone defects, hemophilia, and cancer.

A novel two-step procedure to expand cardiac Sca-1+ cells clonally

Resident cardiac stem cells (CSCs) are characterized by their capacity to self-renew in culture, and are multipotent for forming normal cell types in hearts. CSCs were originally isolated directly from enzymatically digested hearts using stem cell markers. However, long exposure to enzymatic digestion can affect the integrity of stem cell markers on the cell surface, and also compromise stem cell function. Alternatively resident CSCs can migrate from tissue explant and form cardiospheres in culture. However, fibroblast contamination can easily occur during CSC culture. To avoid these problems, we developed a two-step procedure by growing the cells before selecting the Sca-1+ cells and culturing in cardiac fibroblast conditioned medium, they avoid fibroblast overgrowth.

Specific beta1-adrenergic receptor silencing with small interfering RNA lowers high blood pressure and improves cardiac function in myocardial ischemia

OBJECTIVES

Beta-blockers are widely used and effective for treating hypertension, acute myocardial infarction (MI) and heart failure, but they present side-effects mainly due to antagonism of beta2-adrenergic receptor (AR). Currently available beta-blockers are at best selective but not specific for beta1 or beta2-AR.

METHODS

To specifically inhibit the expression of the beta1-AR, we developed a small interfering RNA (siRNA) targeted to beta1-AR. Three different sequences of beta1 siRNA were delivered into C6-2B cells with 90% efficiency.

RESULTS

One of the three sequences reduced the level of beta1-AR mRNA by 70%. The siRNA was highly specific for beta1-AR inhibition with no overlap with beta2-AR. To test this in vivo, systemic injection of beta1 siRNA complexed with liposomes resulted in efficient delivery into the heart, lung, kidney and liver, and effectively reduced beta1-AR expression in the heart without altering beta2-AR. beta1 siRNA significantly lowered blood pressure of spontaneously hypertensive rats (SHR) for at least 12 days and reduced cardiac hypertrophy following a single injection. Pretreatment with beta1 siRNA 3 days before induction of MI in Wistar rats significantly improved cardiac function, as demonstrated by dP/dt and electrocardiogram following the MI. The protective mechanism involved reduction of cardiomyocyte apoptosis in the beta1 siRNA-treated hearts.

CONCLUSIONS

The present study demonstrates the possibility of using siRNA for treating cardiovascular diseases and may represent a novel beta-blocker specific for beta1-AR.

Paracrine action enhances the effects of autologous mesenchymal stem cell transplantation on vascular regeneration in rat model of myocardial infarction

BACKGROUND

There are several reports that engrafted mesenchymal stem cells (MSCs) stimulate angiogenesis in the ischemic heart, but the mechanism remains controversial. We hypothesize that transplantation of MSCs enhances vascular regeneration through a paracrine action.

METHODS

A transmural myocardial infarction was created by ligation of the left anterior descending coronary artery in rats. Those with an ejection fraction less than 0.70 1 week after myocardial infarction were included. Autologous MSCs (1 x 10(7); 0.2 mL) or culture medium (0.2 mL) was injected intramyocardially into the periinfarct zone (50 microL/injection at four sites; n = 20/group). At 2 weeks after transplantation, Western blot analysis was used to assay the paracrine factors and proapoptotic proteins. Echocardiography to assess heart function was performed on additional groups at 8 weeks after implantation.

RESULTS

The angiogenic factors basic fibroblast growth factor, vascular endothelial growth factor, and stem cell homing factor (stromal cell-derived factor -1alpha) increased in the MSC-treated hearts compared with medium-treated hearts. This was accompanied by a downregulation of proapoptotic protein Bax in ischemic myocardium. Similarly, capillary density increased about 40% in MSC-treated hearts compared with medium-treated hearts (p = 0.001). Left ventricular contractility, indicated by fractional shortening, improved in MSC-treated hearts at 2 months after implantation (MSCs: 48.6% +/- 19.9%; medium: 18.7% +/- 6.4%; p = 0.004).

CONCLUSIONS

Autologous MSC transplantation attenuates left ventricular remodeling and improves cardiac performance. The major mechanism appears to be paracrine action of the engrafted cells, increasing angiogenesis and cytoprotection.

A vigilant, hypoxia-regulated heme oxygenase-1 gene vector in the heart limits cardiac injury after ischemia-reperfusion in vivo

OBJECTIVES

The effect of a cardiac specific, hypoxia-regulated, human heme oxygenase-1 (hHO-1) vector to provide cardioprotection from ischemia-reperfusion injury was assessed.

BACKGROUND

When myocardial ischemia and reperfusion is asymptomatic, the damaging effects are cumulative and patients miss timely treatment. A gene therapy approach that expresses therapeutic genes only when ischemia is experienced is a desirable strategy. We have developed a cardiac-specific, hypoxia-regulated gene therapy "vigilant vector'' system that amplifies cardioprotective gene expression.

METHODS

Vigilant hHO-1 plasmids, LacZ plasmids, or saline (n = 40 per group) were injected into mouse heart 2 days in advance of ischemia-reperfusion injury. Animals were exposed to 60 minutes of ischemia followed by 24 hours of reperfusion. For that term (24 hours) effects, the protein levels of HO-1, inflammatory responses, apoptosis, and infarct size were determined. For long-term (3 week) effects, the left ventricular remodeling and recovery of cardiac function were assessed.

RESULTS

Ischemia-reperfusion resulted in a timely overexpression of HO-1 protein. Infarct size at 24 hours after ischemia-reperfusion was significantly reduced in the HO-1-treated animals compared with the LacZ-treated group or saline-treated group (P < .001). The reduction of infarct size was accompanied by a decrease in lipid peroxidant activity, inflammatory cell infiltration, and proapoptotic protein level in ischemia-reperfusion-injured myocardium. The long-term study demonstrated that timely, hypoxia-induced HO-1 overexpression is beneficial in conserving cardiac function and attenuating left ventricle remodelling.

CONCLUSIONS

The vigilant HO-1 vector provides a protective therapy in the heart for reducing cellular damage during ischemia-reperfusion injury and preserving heart function.

A hypoxia-inducible vigilant vector system for activating therapeutic genes in ischemia

Hypoxia represents an endogenous pathophysiological signal underlying cell growth, adaptation and death in a variety of diseases, including ischemic heart diseases, stroke and solid tumors. A vigilant vector system depends on a gene switch which can sense the hypoxia signal occurring in ischemic events and turn on/off protective gene expressions when necessary. This system uses the oxygen-dependent degradation domain derived from hypoxia-inducible factor 1alpha as the hypoxia sensor and a double-vector system as signal amplifier. For treating ischemic heart diseases, a cardiac-specific MLC-2v promoter is used to deliver transgenes specifically to the heart. When tested in cardiomyocyte cultures, it produced a rapid and robust gene induction upon exposure to low oxygen. In a mouse model for myocardial infarction, the vigilant vectors turned on therapeutic genes such as heme oxygenase-1 in response to ischemia, significantly reduced apoptosis in the infarct area and improved cardiac functions. The hypoxia-regulated gene transfer afforded by the vigilant vectors may provide a powerful tool for delivering therapeutic proteins specifically to ischemic tissues with optimal physiological control.

Improved graft mesenchymal stem cell survival in ischemic heart with a hypoxia-regulated heme oxygenase-1 vector

OBJECTIVES

The goal of this study was to modify mesenchymal stem cells (MSCs) cells with a hypoxia-regulated heme oxygenase-1 (HO-1) plasmid to enhance the survival of MSCs in acute myocardial infarction (MI) heart.

BACKGROUND

Although stem cells are being tested clinically for cardiac repair, graft cells die in the ischemic heart because of the effects of hypoxia/reoxygenation, inflammatory cytokines, and proapoptotic factors. Heme oxygenase-1 is a key component in inhibiting most of these factors.

METHODS

Mesenchymal stem cells from bone marrow were transfected with either HO-1 or LacZ plasmids. Cell apoptosis was assayed in vitro after hypoxia-reoxygen treatment. In vivo, 1 x 10(6) of male MSC(HO-1), MSC(LacZ), MSCs, or medium was injected into mouse hearts 1 h after MI (n = 16/group). Cell survival was assessed in a gender-mismatched transplantation model. Apoptosis, left ventricular remodeling, and cardiac function were tested in a gender-matched model.

RESULTS

In the ischemic myocardium, the MSC(HO-1) group had greater expression of HO-1 and a 2-fold reduction in the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick end labeling-positive cells compared with the MSC(LacZ) group. At seven days after implantation, the survival MSC(HO-1) was five-fold greater than the MSC(LacZ) group; MSC(HO-1) also attenuated left ventricular remodeling and enhanced the functional recovery of infarcted hearts two weeks after MI.

CONCLUSIONS

A hypoxia-regulated HO-1 vector modification of MSCs enhances the tolerance of engrafted MSCs to hypoxia-reoxygen injury in vitro and improves their viability in ischemic hearts. This demonstration is the first showing that a physiologically inducible vector expressing of HO-1 genes improves the survival of stem cells in myocardial ischemia.

Autologous mesenchymal stem cells for post-ischemic myocardial repair

Cell transplantation is a novel therapy for patients with postinfarction ventricular dysfunction and congestive heart failure. The potential of mesenchymal stem cells (MSCs) to be used in the injured myocardium is unlimited because of their ability to self-renew and differentiate into cardiomyocytes in vitro and in vivo. In addition, MSCs are easy to harvest and have a high proliferation capability. Finally, autologous MSCs can survive permanently and integrate with healthy host tissue to form new myocardium after implantation in vivo. We have used autologous cultured MSCs grafts for mouse and rat myocardial infarction in more than 500 cases. From these grafting experiments, it has been shown that cultured autologous MSCs grafting is a useful approach in the treatment of ischemic heart failure. This chapter offers a step-by-step guide for successful research on cultured MSCs for the treatment of myocardial infarction, as well as a set of techniques for evaluating postimplantation myocardial repair.

Cellular therapy with autologous skeletal myoblasts for ischemic heart disease and heart failure

Cardiomyocytes are final differentiated cells that lose the ability to regenerate. Autologous cellular transplantation for cardiac repair has recently emerged as a promising new approach for end-stage heart failure that avoids the risk of immune rejection and ethical problems. Skeletal myoblasts (or satellite cells) are committed progenitor cells located under the basal lamina of adult skeletal muscle; they are committed to multiply after injury. They are highly resistant to ischemia and possess a considerable potential for division in culture. The cardiac milieu might alter the developmental program of grafted myoblast and facilitate their conversion to the slow-twitch phenotype, which is capable of performing cardiac work. We have used autologous cultured myoblast grafts for mouse and rat myocardial infarction in more than 200 cases. From these grafting experiments, it has been shown that cultured autologous myoblast grafting is a useful technique in the treatment of ischemic heart failure. This chapter offers a step-by-step guide to a successful research project on cultured myoblasts for the treatment of myocardial infarction, as well as a set of special techniques for yielding large numbers of skeletal myoblasts and studying postimplantation myocardial repair.

Mobilizing of haematopoietic stem cells to ischemic myocardium by plasmid mediated stromal-cell-derived factor-1alpha (SDF-1alpha) treatment

A concentration gradient of stromal-cell-derived factor-1alpha (SDF-1alpha) is the major mechanism for homing of haematopoietic stem cells (HSCs) in bone marrow. We tested the hypothesis that a gene therapy using SDF-1alpha can enhance HSCs recruiting to the heart upon myocardial infarction (MI). Adult mice with surgically induced myocardial ischemia were injected intramyocardially with either saline (n=12) or SDF-1alpha plasmid (n=12) in 50 microl volume in the ischemic border zone of the infarcted heart 2 weeks after myocardial infarction. Donor Lin-c-kit+ HSCs from isogenic BalB/c mice were harvested, sorted through magnetic cell sorting (MACS) and labeled with PKH26 Red. Three days after plasmid or saline injection, 1x10(5) labeled cells were injected intravenously (i.v.) into saline mice (n=4) and SDF-1alpha plasmid mice (n=4). The hearts and other tissue were removed for Western blot assay 2 weeks after plasmid or saline treatment. The labeled Lin-c-kit+ cells were identified with immunofluoresent staining and endogenous c-kit+ cells were identified by immunohistochemical staining. In mice killed at 1 month postinfarct, Western blot showed higher levels of SDF-1alpha expression in SDF-1alpha-treated mouse ischemic hearts compared to saline-treated hearts and other tissues. In the SDF-1alpha plasmid-treated hearts, SDF-1alpha is overexpressed in the periinfarct zone. The labeled stem cells engrafted to the SDF-1alpha positive site in the myocardium. There was also evidence for endogenous stem cell recruiting. The density of c-kit+ cells in border zone, an index of endogenous stem cell mobilization, was significantly higher in the SDF-1alpha-treated group than in the saline group (14.63+/-1.068 cells/hpf vs. 11.31+/-0.65 cells/hpf, P=0.013) at 2 weeks after SDF-1alpha or saline treatment. Following myocardial infarction, treatment with SDF-1alpha recruits stem cells to damaged heart where they may have a role in repairing and regeneration. The gene therapy with an SDF-1alpha vector offers a promising therapeutic strategy for mobilizing stem cells to the ischemic myocardium.