Artemisia argyi exhibits anti-aging effects through decreasing the senescence in aging stem cells

Aging is accompanied by functional loss of many cellular pathways, creating an increased risk of many age-related complications (ARC). Aging causes stem cell exhaustion with a concomitant increase in cellular dysfunction. Recently, interest in senotherapeutics has been growing rapidly to promote healthy aging and as an intervention for ARCs. This research focused on screening the senomorphic properties of Artemisia argyi, as an emerging strategy for longevity, and prevention or treatment of ARCs. In this study, we aimed to find the clinical efficacy of daily consumption of Artemisia argyi water extract (AAW) on aging. In vitro 0.1μM Doxorubicin induced senescent human adipose derived mesenchymal stem cells was treated with different concentrations of AAW to show its anti-aging effect. 15 months old SHR rats (n=6) were treated with 7.9 mg/ml AAW for 4 weeks and anti-aging effect was evaluated. In vitro study showed the protective effect of AAW in telomere shortening and helps in maintaining a balance in the expression of anti-aging protein Klotho and TERT. AAW effectively reduced mitochondrial superoxide and also provided a protective shield against senescence markers like over-expression of p21 and formation of double strand breaks, which is known to cause premature aging. Moreover, animal studies indicated that AAW promoted the expression of Klotho in naturally aging rats. In addition, AAW successfully restored the decline cardiac function and improved the grip strength and memory of aging rat. These findings showed that therapeutic targeting of senescent stem cells by AAW restored stem cell homeostasis and improves overall health.

STEER: 3D Printed Guide for Nerve Regrowth Control and Neural Interface in Non-Human Primate Model

OBJECTIVE

Peripheral neural interface (PNI) with a stable integration of synthetic elements with neural tissue is key for successful neuro-prosthetic applications. An inevitable phenomenon of reactive fibrosis is a primary hurdle for long term functionality of PNIs. This proof-of-concept study aimed to fabricate and test a novel, stable PNI that harnesses fibro-axonal outgrowth at the nerve end and includes fibrosis in the design.

METHODS

Two non-human primates were implanted with Substrate-guided, Tissue-Electrode Encapsulation and Integration (STEER) PNIs. The implant included a 3D printed guide that strove to steer the regrowing nerve towards encapsulation of the electrodes into a fibro-axonal tissue. After four months from implantation, we performed electrophysiological measurements to test STEERs functionality and examined the macro and micro- morphology of the outgrowth tissue.

RESULTS

We observed a highly structured fibro-axonal composite within the STEER PNI. A conduction of intracranially generated action potentials was successfully recorded across the neural interface. Immunohistology demonstrated uniquely configured laminae of myelinated axons encasing the implant.

CONCLUSION

STEER PNI reconfigured the structure of the fibro-axonal tissue and facilitated long-term functionality and stability of the neural interface.

SIGNIFICANCE

The results point to the feasibility of our concept for creating a stable PNI with long-term electrophysiologic functionality by using simple design and materials.

Convolutional Neural Network for Freezing of Gait Detection Leveraging the Continuous Wavelet Transform on Lower Extremities Wearable Sensors Data

Freezing of Gait is the most disabling gait disturbance in Parkinson's disease. For the past decade, there has been a growing interest in applying machine learning and deep learning models to wearable sensor data to detect Freezing of Gait episodes. In our study, we recruited sixty-seven Parkinson's disease patients who have been suffering from Freezing of Gait, and conducted two clinical assessments while the patients wore two wireless Inertial Measurement Units on their ankles. We converted the recorded time-series sensor data into continuous wavelet transform scalograms and trained a Convolutional Neural Network to detect the freezing episodes. The proposed model achieved a generalisation accuracy of 89.2% and a geometric mean of 88.8%.

Saccades and Subjective Time in Seconds Range Duration Reproduction

A transient suppression of visual perception during saccades ensures perceptual stability. In two experiments, we examined whether saccades affect time perception of visual and auditory stimuli in the seconds range. Specifically, participants completed a duration reproduction task in which they memorized the duration of a 6 s timing signal during the training phase and later reproduced that duration during the test phase. Four experimental conditions differed in saccade requirements and the presence or absence of a secondary discrimination task during the test phase. For both visual and auditory timing signals, participants reproduced longer durations when the secondary discrimination task required saccades to be made (i.e., overt attention shift) during reproduction as compared to when the discrimination task merely required fixation at screen center. Moreover, greater total saccade duration in a trial resulted in greater time distortion. However, in the visual modality, requiring participants to covertly shift attention (i.e., no saccade) to complete the discrimination task increased reproduced duration as much as making a saccade, whereas in the auditory modality making a saccade increased reproduced duration more than making a covert attention shift. In addition, we examined microsaccades in the conditions that did not require full saccades for both the visual and auditory experiments. Greater total microsaccade duration in a trial resulted in greater time distortion in both modalities. Taken together, the experiments suggest that saccades and microsaccades affect seconds range visual and auditory interval timing via attention and saccadic suppression mechanisms.

Singapore Tele-technology Aided Rehabilitation in Stroke (STARS) trial: protocol of a randomized clinical trial on tele-rehabilitation for stroke patients

Background

Most acute stroke patients with disabilities do not receive recommended rehabilitation following discharge to the community. Functional and social barriers are common reasons for non-adherence to post-discharge rehabilitation. Home rehabilitation is an alternative to centre-based rehabilitation but is costlier. Tele-rehabilitation is a possible solution, allowing for remote supervision of rehabilitation and eliminating access barriers. The objective of the Singapore Tele-technology Aided Rehabilitation in Stroke (STARS) trial is to determine if a novel tele-rehabilitation intervention for the first three months after stroke admission improves functional recovery compared to usual care.

Methods/design

This is a single blind (evaluator blinded), parallel, two-arm randomised controlled trial study design involving 100 recent stroke patients. The inclusion criteria are age ≥40 years, having caregiver support and recent stroke defined as stroke diagnosis within 4 weeks. Consenting participants will be randomized with varying block size of 4 or 6 assuming a 1:1 treatment allocation with the participating centre as the stratification factor. The baseline assessment will be done within 4 weeks of stroke onset, followed by follow-up assessments at 3 and 6 months. The tele-rehabilitation intervention lasts for 3 months and includes exercise 5-days-a-week using an iPad-based system that allows recording of daily exercise with video and sensor data and weekly video-conferencing with tele-therapists after data review. Those allocated to the control group will receive usual care. The primary outcome measure is improvement in life task’s social activity participation at three months as measured by the disability component of the Jette Late Life Functional and Disability Instrument (LLFDI). Secondary outcome variables consist of gait speed (Timed 5-Meter Walk Test) and endurance (Two-Minute Walk test), performance of basic activities of daily living (Shah-modified Barthel Index), balance confidence (Activities-Specific Balance Confidence Scale), patient self-reported health-related quality-of-life [Euro-QOL (EQ-5D)], health service utilization (Singapore Stroke Study Health Service Utilization Form) and caregiver reported stress (Zarit Caregiver Burden Inventory).

Discussion

The goal of this trial is to provide evidence on the potential benefit and cost-effectiveness of this novel tele-rehabilitation programme which will guide health care decision-making and potentially improve performance of post-stroke community-based rehabilitation.

Trial Registration

This trial protocol was registered under ClinicalTrials.gov on 18 July 2013 as study title “The Singapore Tele-technology Aided Rehabilitation in Stroke (STARS) Study” (ID: The STARS Study, ClinicalTrials.gov Identifier: NCT01905917).

The stage-dependent inhibitory effect of porcine follicular cells on the development of preantral follicles

The objective of this study was to examine the effects of follicular cells on the in vitro development of porcine preantral follicles. In Experiment 1, one preantral follicle alone (Trt 1) was cocultured with a follicle of the same size with oocytes (Trt 2) or without oocytes (Trt 3). Preantral follicles cultured alone in vitro for 12 days had greater follicle diameters (1017 +/- 96 microm versus 706 +/- 69 or 793 +/- 72 microm, P < 0.05), growth rates (201 +/- 0.3 versus 103 +/- 0.2 or 128 +/- 0.2, P < 0.05) and oocyte survival rates (73% versus 48, or 25%, P < 0.05) than other groups. The inhibitory effects of follicle cells on the growth of preantral follicles and oocyte survival rates were not enhanced by the addition of oocytectomized preantral follicles (Experiment 2). Follicles were cocultured with different sources of follicular cells in other experiments. Coculture with cumulus cells enhanced oocyte survival compared to the control (without coculture) and mural follicular cell groups (Experiment 3). The growth and survival rates of oocytes collected from the group of follicles cocultured with cumulus cells from large antral follicles (>3 mm) were greater (P < 0.05) than those from small antral follicles (<3 mm), or than the control group (without cumulus cells, experiment 4). No significant differences in the follicular diameters (674 +/- 30 microm versus 638 +/- 33 and 655 +/- 28 microm) and growth rate (105% versus 94 and 105%) were observed among the preantral follicles of the different treatments (P > 0.05). Taken together, coculture with the cells from large antral follicles (>3 mm) exerted a significant positive effect on oocyte survival. The growth and oocyte survival of preantral follicle cocultured with the same size of follicles (with or without oocyte) were inhibited. Growth and survival rates of preantral follicles and oocytes are improved by coculturing them with the cumulus cells derived from larger antral follicles.

Combination of a new composite biocampatible skin graft on the neodermis of artificial skin in an animal model

INTRODUCTION

There have been very limited and inconsistent attempts at combining the cultured epidermal autograft (CEA) with the neodermis of artificial skin (Integra). The reasons for this remain unknown. The basement membrane proteins of conventional CEA sheets are easily damaged by the dispase treatment during the harvesting of the CEA from the culture flask. The damage of the basement membrane proteins may affect the anchorage of CEA onto the neodermis of Integra. A new Composite Biocompatible Skin Graft (CBSG) was recently developed.

METHODS

Composite biocompatible skin graft consists of autologous keratinocytes cultivated on a pliable hyaluronate-derived membrane (Laserskin)which has been pre-seeded with allogenic dermal fibroblasts. Basement membrane proteins of CBSG are protected from the dispase treatment because the keratinocytes are directly seeded onto Laserskin. The engraftment of CBSG was evaluated on 20 wounds of 10 rats. Integrawas grafted on two freshly excised full-thickness wounds (3cm in diameter) in the dorsum of each animal. A polypropylene ring was applied to each wound to prevent the migration of epithelium from the edges. Composite Biocompatible Skin Graft was used to cover the neodermis of Integra after the silicone membrane was removed 14-21 days postgrafting.

RESULTS

Fourteen (70%) of 20 skin biopsies taken at day 21 from the centre of the grafted wounds revealed regenerated epithelium.

CONCLUSION

A feasible delivery system of cultured keratinocytes onto theneodermis of Integra is demonstrated in this animal -experiment.

The efficacy of collagen dermis membrane and fibrin on cultured epidermal graft using an athymic mouse model

A human skin substitute consisting of human cultured keratinocytes, collagen dermis, and fibrin was evaluated in athymic mice. Eighty athymic mice were divided randomly into four groups. A 1.5x1.5-cm full-thickness wound defect was created on the back of each athymic mouse under anesthesia. These wounds were covered by sheets of cultured epidermal graft (group A), cultured epidermal graft with collagen dermis and fibrin (group B), cultured epidermal graft with collagen dermis (group C), or cultured epidermal graft with fibrin (group D). The grafts were secured and kept moist by specially designed saline gauze chambers. The take rates of the cultured graft with more than 50% of the wound covered were 65%, 15%, 50%, and 45% respectively. Group B had a significantly lower graft take rate, however the difference was not significant among groups A, C, and D. Light microscopy of biopsies of the grafted sites at 12 days showed complete epithelialization. The incidence of discharge from wound beds in groups A, B, C, and D was 0%, 15%, 15%, and 10% respectively. The results suggest that cultured cells are best grafted directly onto the wound bed or in combination with either a thin layer of collagen or fibrin but not both because the collagen dermal membrane and the fibrin together may impose too great a diffusion barrier for the cultured cell graft to become vascularized.

Development and evaluation of a new composite Laserskin graft

BACKGROUND

Tremendous effort has been made to improve the graft take rate of cultured epidermal autograph. The purpose of this study is to develop and evaluate a new composite Laserskin graft (CLSG) as a human skin substitute for wound resurfacing.

METHODS

The seeding efficacy of cultured keratinocytes on plain Laserskin was compared with the 3T3 cell-seeded Laserskin and allogenic fibroblast-populated Laserskin. Three different types of CLSG, 2 cm in diameter each, were prepared and tested in rats. Type A CLSG consisted of proliferative allogenic rat fibroblasts on both sides of the Laserskin with autologous keratinocytes also on the upper side. Fibroblasts and keratinocytes were seeded only on the upper side of the Laserskin in type B CLSG. Keratinocytes alone were seeded on plain Laserskin in type C CLSG. Type B CLSG consisting of autologous keratinocytes and autologous dermal fibroblasts was tested on five selected wounds (5x5 cm each) of a patient with full-thickness burn. In another burn patient, type B CLSG consisting of autologous keratinocytes and allogenic dermal fibroblasts was grafted onto three wounds (5x5 cm each).

RESULTS

The seeding efficacy of human keratinocytes on plain Laserskin increased from 75% to 95% when proliferative allogenic fibroblasts were grown as a feeder layer on the Laserskin. The seeding efficacy of rat keratinocytes increased from 36% to 88% in the presence of a proliferative allogenic fibroblast feeder layer, whereas human/rat keratinocytes had respective seeding efficacy of 98%/91% on Laserskin preseeded with mitomycin C-treated 3T3 cells. Skin biopsies of grafted type A CLSG on day 14 after grafting showed complete epithelialization without severe inflammation in 16 of 20 (80%) grafted surgical wounds in rats. There were eight (40%) and seven (35%) "takes" of the CLSG in types B and C, respectively. The infection rate in type B CLSG was two (10%). There was one (5%) infection in types A and C. The respective take rates on the two patients grafted with type B CLSG were 60% and 100%.

CONCLUSION

The animal experiment and the preliminary clinical data showed that the CSLGs consisting of autologous keratinocytes and of autologous/allogenic fibroblasts are good human skin substitutes in terms of durability, biocompatibility, high seeding efficacy for keratinocytes, high graft take rate, and low infection rate.

PAK promotes morphological changes by acting upstream of Rac

The serine/threonine kinase p21-activated kinase (PAK) has been implicated as a downstream effector of the small GTPases Rac and Cdc42. While these GTPases evidently induce a variety of morphological changes, the role(s) of PAK remains elusive. Here we report that overexpression of betaPAK in PC12 cells induces a Rac phenotype, including cell spreading/membrane ruffling, and increased lamellipodia formation at growth cones and shafts of nerve growth factor-induced neurites. These effects are still observed in cells expressing kinase-negative or Rac/Cdc42 binding-deficient PAK mutants, indicating that kinase- and p21-binding domains are not involved. Furthermore, lamellipodia formation in all cell lines, including those expressing Rac binding-deficient PAK, is inhibited significantly by dominant-negative RacN17. Equal inhibition is achieved by blocking PAK interaction with the guanine nucleotide exchange factor PIX using a specific N-terminal PAK fragment. We conclude that PAK, via its N-terminal non-catalytic domain, acts upstream of Rac mediating lamellipodia formation through interaction with PIX.

Extraction of perceptually salient contours by striate cortical networks

We present a cortical-based model for computing the perceptual salience of contours embedded in noisy images. It has been suggested that horizontal intra-cortical connections in primary visual cortex may modulate contrast detection thresholds and pre-attentive "pop-out". In our model, horizontal connections mediate context-dependent facilitatory and inhibitory interactions among oriented cells. Strongly facilitated cells undergo temporal synchronization; and perceptual salience is determined by the level of synchronized activity. The model accounts for a range of reported psychophysical and physiological effects of contour salience. In particular, the model proposes that intrinsic properties of synchronization account for the increased salience of smooth, closed contours. Application of the model to real images is demonstrated.

Coarse-grain parallel computing for very large scale neural simulations in the NEXUS simulation environment

We describe a neural simulator designed for simulating very large scale models of cortical architectures. This simulator, NEXUS, uses coarse-grain parallel computing by distributing computation and data onto multiple conventional workstations connected via a local area network. Coarse-grain parallel computing offers natural advantages in simulating functionally segregated neural processes. We partition a complete model into modules with locally dense connections--a module may represent a cortical area, column, layer, or functional entity. Asynchronous data communications among workstations are established through the Network File System, which, together with the implicit modularity, decreases communications overhead, and increases overall performance. Coarse-grain parallelism also benefits from the standardization of conventional workstations and LAN, including portability between generations and vendors.

Regulation of insulin-like growth factor binding protein-1 during the 24-hour metabolic clock and in response to hypoinsulinemia induced by fasting and Sandostatin in normal women

OBJECTIVE

To establish the relation of insulin-like growth factor-I (IGF-I) and IGF-binding protein-1 (IGFBP-1) with 24-hour metabolic excursions in normal healthy women and in response to acute interruption of metabolic homeostasis by hypoinsulinemia.

METHODS

Hourly blood samples during the 24-hour metabolic clock were obtained from seven normally cycling women. Uniform dietary composition (50% carbohydrate, 35% fat, and 15% protein) and timing of meals (8 AM, 12 PM, and 6 PM) were prescribed. Daytime hypoinsulinemia was induced by omitting meals and by Sandostatin (100 micrograms) administration. Changes in serum levels of glucose, insulin, cortisol, IGF-I, and IGFBP-1 were measured.

RESULTS

The diurnal pattern of serum IGFBP-1 levels during the 24-hour metabolic clock was characterized by a rapid fall during the feeding phase of the day and a progressive 3.5-fold rise during nocturnal fasting; IGF-I levels were unchanged. Changes in IGFBP-1 levels were in parallel to those of cortisol and were inversely related to increases in glucose (80%) and insulin (tenfold) levels after each meal and to their decline during nocturnal fasting. Daytime fasting and administration of Sandostatin were accompanied by rapid and sustained increases in IGFBP-1 when insulin levels declined to 54 +/- 20 pmol/L.

CONCLUSIONS

With constant levels of IGF-I, the diurnal rhythm of IGFBP-1 may subserve a physiologic function by coordinating insulin and IGF-I action with substrate availability. Fluctuations of insulin levels during the 24-hour metabolic clock in normal women appear to serve as a signal, with an inhibitory effect on IGFBP-1 production when levels are above 70 pmol/L and a stimulatory effect at levels below 70 pmol/L. These findings provide a basis for future investigations in women with nutritionally related reproductive disorders.

The premenstrual syndrome. Effects of "medical ovariectomy"

In a crossover study conducted over a six-month period in eight patients with well-characterized premenstrual syndrome, physical and behavioral symptoms were relieved by daily administration of an agonist of gonadotropin-releasing hormone. The reversible "medical ovariectomy" attained with this agonist suggests that it may be an effective and rational treatment for this distressing syndrome in the short term. Whether prolonged therapy would be safe and effective, or even necessary, remains to be determined.