Regulation of Bone Marrow Stem Cells through Oscillatory Shear Stresses - A Heart Valve Tissue Engineering Perspective

Heart valve disease occurs in adults as well as in pediatric population due to age-related changes, rheumatic fever, infection or congenital condition. Current treatment options are limited to mechanical heart valve (MHV) or bio-prosthetic heart valve (BHV) replacements. Lifelong anti-coagulant medication in case of MHV and calcification, durability in case of BHV are major setbacks for both treatments. Lack of somatic growth of these implants require multiple surgical interventions in case of pediatric patients. Advent of stem cell research and regenerative therapy propose an alternative and potential tissue engineered heart valves (TEHV) treatment approach to treat this life threatening condition. TEHV has the potential to promote tissue growth by replacing and regenerating a functional native valve. Hemodynamics play a crucial role in heart valve tissue formation and sustained performance. The focus of this study was to understand the role of physiological shear stress and flexure effects on de novo HV tissue formation as well as resulting gene and protein expression. A bioreactor system was used to generate physiological shear stress and cyclic flexure. Human bone marrow mesenchymal stem cell derived tissue constructs were exposed to native valve-like physiological condition. Responses of these tissue constructs to the valve-relevant stress states along with gene and protein expression were investigated after 22 days of tissue culture. We conclude that the combination of steady flow and cyclic flexure helps support engineered tissue formation by the co-existence of both OSS and appreciable shear stress magnitudes, and potentially augment valvular gene and protein expression when both parameters are in the physiological range

Differentiation and Distribution of Marrow Stem Cells in Flex-Flow Environments Demonstrate Support of the Valvular Phenotype

For treatment of critical heart valve diseases, prosthetic valves perform fairly well in most adults; however, for pediatric patients, there is the added requirement that the replacement valve grows with the child, thus extremely limiting current treatment options. Tissue engineered heart valves (TEHV), such as those derived from autologous bone marrow stem cells (BMSCs), have the potential to recapitulate native valve architecture and accommodate somatic growth. However, a fundamental pre-cursor in promoting directed integration with native tissues rather than random, uncontrolled growth requires an understanding of BMSC mechanobiological responses to valve-relevant mechanical environments. Here, we report on the responses of human BMSC-seeded polymer constructs to the valve-relevant stress states of: (i) steady flow alone, (ii) cyclic flexure alone, and (iii) the combination of cyclic flexure and steady flow (flex-flow). BMSCs were seeded onto a PGA: PLLA polymer scaffold and cultured in static culture for 8 days. Subsequently, the aforementioned mechanical conditions, (groups consisting of steady flow alone-850ml/min, cyclic flexure alone-1 Hz, and flex-flow-850ml/min and 1 Hz) were applied for an additional two weeks. We found samples from the flex-flow group exhibited a valve-like distribution of cells that expressed endothelial (preference to the surfaces) and myofibroblast (preference to the intermediate region) phenotypes. We interpret that this was likely due to the presence of both appreciable fluid-induced shear stress magnitudes and oscillatory shear stresses, which were concomitantly imparted onto the samples. These results indicate that flex-flow mechanical environments support directed in vitro differentiation of BMSCs uniquely towards a heart valve phenotype, as evident by cellular distribution and expression of specific gene markers. A priori guidance of BMSC-derived, engineered tissue growth under flex-flow conditions may serve to subsequently promote controlled, engineered to native tissue integration processes in vivo necessary for successful long-term valve remodeling

Effect of Valsalva Maneuver on Pain Perception During Blood Sample Collection Among Patients

Background: Blood sample collection is the most frequent intrusive practise that hurts patients in hospital settings. A non-pharmacological and economical way to lessen pain during blood sample collection is the Valsalva Maneuver. Objectives; The aim of this study was to evaluate the effect of Valsalva Maneuver during blood sample collection. Methods: A quasi-experimental design (post-test only control group design). Self-structured questionnaire on Socio demographic information, clinical parameter and Wong baker face pain scale was used to observe the pain score of participants. The research population includes all the adult patients between the ages of 18 and 50 admitted in IPD. The sample size for the study comprises of 500 Participants who met the inclusion criteria. Purposive sampling technique was used to identify adult patients between the ages of 18 and 50 who were having blood sample collection admitted in IPD in IMS & SUM hospital, Bhubaneswar, Odisha. Results: The results revealed that there is significant reduction in pain during blood sample collection in experimental group with (p=0.000). No association was found between level pain and socio-demographic and clinical parameters. Discussion: The Valsalva manoeuvre is a non-invasive, non-pharmacological, and efficient way to lessen pain related to drawing blood samples. During the collection of blood samples, nurses should demonstrate the Valsalva manoeuvre to patients. In-service education programmes for nurses and students should be included by hospital administration in order to promote the non-pharmacological technique of pain alleviation during blood sample collection

Successful treatment of ureteric calculi with constitutional homoeopathic medicine Lycopodium clavatum: A Case report

Introduction Formation of stone in the urinary tract, kidney, ureter and bladder is called as Urolithiasis. Formation of urinary stones is very common. About 5-15% population are affected with urinary stone, and, therefore, causes high morbidity in comparison to the above types of stone formation. Shock wave lithotripsy and ureteroscopy along with conservative treatments are the most common approaches for the treatment of calculi, although considered as expressive in one hand, and on the other hand, such interventions may lead to complications. Therefore, alternative medicines give a second thought for the treatment of urolithiasis because it avoids surgical interventions. Here we present a case study for the successful treatment of urolithiasis by a homoeopathic medicine Lycopodium clavatum in a 43 years old male. Case Profile A 43-year-old male patient with intense pain in the right loin for 5-6 days, increased frequency of urination, ineffectual urination, severe pain during urination, and finally with the pain score was 9, was considered for treatment in the present study. Based on his complete case history, Lycopodium clavatum at potencies of 0/1 to 0/6 was prescribed to him. Conclusion Correct homoeopathic organ specific or constitutional formulation(s) selected based on specific important symptoms can also be efficacious in diseases such as ureteric stone. Constitutional medicine Lycopodium clavatum is usually prescribed when the patient is with right side pain with ureteric stone and it is justified in the present case report. Randomized control trial is suggested to ascertain the results obtained in the present study i.e. successful treatment of urolithiasis with the constitutional homeopathic formulation Lycopodium clavatum

Marrow Stem Cell Differentiation for Valvulogenesis via Oscillatory Flow and Nicotine Agonists: Unusual Suspects?

Fluid-induced oscillatory shear stress (OSS) and nicotine are known antagonists in cardiovascular disease. However, from a regenerative medicine standpoint, we hypothesized that these parameters may support the cell differentiation of bone marrow mesenchymal stem cells (BMMSCs) for engineering heart valves. In this study, OSS and nicotine (10-6M) were applied individually to BMMSCs in monolayer culture. In both cases, a significantly higher expression of CD31 was detected compared to corresponding controls (p\u3c0.05). We interpret our findings to indicate that both OSS and nicotine independently support mesenchymal to endothelial transformation; however, the underlying mechanism for this transformation in terms of the cell cytoskeletal structure was entirely different between the two stimulants. In the case of OSS, F-actin filaments exhibited a stretching response and formed a preferential alignment with each other. However, in the nicotine-treated group, a clear increase was observed in the number of actin filaments present, which led to the maximum expression of CD31 in comparison to the OSS and control groups. From our findings, we speculate that while nicotine may stimulate an increase in the differentiation of BMMSCs to endothelial cells, OSS may play a greater role in cellular distribution and the eventual creation of a tissue engineered heart valve (TEHV) endothelium

Impact of COVID-19 Lockdown on Continuation of Treatment among the OPD Geriatric Patients

The aim of the study was to identify the impact of COVID-19 lockdown on continuation of treatment among the OPD geriatric patients. Quantitative research study has been conducted. A descriptive research design and convenience sampling technique were used to pick a total of 100 samples, (n=100). Self-structured socio demographic questionnaire and self structured interview method were used to collect the data in November 2020 at tertiary care hospitals, Bhubaneswar, Odisha, India. The collected data were analyzed through descriptive and inferential statistics. Comparison of three categories of COVID-19 pandemic factors affecting in availing OPD services reveals that the psychological factor has more effect (73%) followed by hospital related factors (68%) and the availability of public transportation and resources (62%) has less effect in availing OPD services among patients during COVID-19 pandemic. Application of chi square test reveals that there is no significant relationship of intensity of COVID-19 pandemic factors affecting in availing OPD services among patients with selected socio demographic variables. These findings suggest that facility for sanitization of hospital premises, facility for social distancing in registration counter, waiting area and other areas of hospital are not quite satisfactory. Factors like availability of public transport, availability of healthcare personnel’s in OPD, adequacy of treatment facility, cost of medical services, availability of diagnostic services, are highly affecting geriatric patients in availing OPD services during COVID-19 pandemic and need to be taken care

Relative Effects of Fluid Oscillations and Nutrient Transport in the In Vitro Growth of Valvular Tissues

Engineered valvular tissues are cultured dynamically, and involve specimen movement. We previously demonstrated that oscillatory shear stresses (OSS) under combined steady flow and specimen cyclic flexure (flex-flow) promote tissue formation. However, localized efficiency of specimen mass transport is also important in the context of cell viability within the growing tissues. Here, we investigated the delivery of two essential species for cell survival, glucose and oxygen, to 3-dimensional (3D) engineered valvular tissues. We applied a convective-diffusive model to characterize glucose and oxygen mass transport with and without valve-like specimen flexural movement. We found the mass transport effects for glucose and oxygen to be negligible for scaffold porosities typically present during in vitro experiments and non-essential unless the porosity was unusually low (0.05). Based on this result, we conducted an experiment using bone marrow stem cell (BMSC)-seeded scaffolds under Pulsatile flow-alone states to permit OSS without any specimen movement. BMSC-seeded specimen collagen from the pulsatile flow and flex-flow environments were subsequently found to be comparable (p \u3e 0.05) and exhibited some gene expression similarities. We conclude that a critical magnitude of fluid-induced, OSS created by either pulsatile flow or flex-flow conditions, particularly when the oscillations are physiologically-relevant, is the direct, principal stimulus that promotes engineered valvular tissues and its phenotype, whereas mass transport benefits derived from specimen movement are minimal

Stem Cell Cytoskeletal Responses to Pulsatile Flow in Heart Valve Tissue Engineering Studies

Heart valve replacement options remain exceedingly limited for pediatric patients because they cannot accommodate somatic growth. To overcome this shortcoming, heart valve tissue engineering using human bone marrow stem cells (HBMSCs) has been considered a potential solution to the treatment of critical congenital valvular defects. The mechanical environments during in vitro culture are key regulators of progenitor cell fate. Here, we report on alterations in HBMSCs, specifically in their actin cytoskeleton and their nucleus under fluid-induced shear stresses of relevance to heart valves. HBMSCs were seeded in microfluidic channels and were exposed to the following conditions: pulsatile shear stress (PSS), steady shear stress (SS), and no flow controls (n = 4/group). Changes to the actin filament structure were monitored and subsequent gene expression was evaluated. A significant increase (p < 0.05) in the number of actin filaments, filament density and angle (between 30° and 84°), and conversely a significant decrease (p < 0.05) in the length of the filaments were observed when the HBMSCs were exposed to PSS for 48 h compared to SS and no flow conditions. No significant differences in nuclear shape were observed among the groups (p > 0.05). Of particular relevance to valvulogenesis, klf2a, a critical gene in valve development, was significantly expressed only by the PSS group (p < 0.05). We conclude that HBMSCs respond to PSS by alterations to their actin filament structure that are distinct from SS and no flow conditions. These changes coupled with the subsequent gene expression findings suggest that at the cellular level, the immediate effect of PSS is to initiate a unique set of quantifiable cytoskeletal events (increased actin filament number, density and angle, but decrease in filament length) in stem cells, which could be useful in the fine-tuning of in vitro protocols in heart valve tissue engineering

Immunofluorescence staining of CD31, an EC marker, on both surface layers (~90μm thickness on each side), middle core sections (~400 μm thickness) of the valve tissue; 1^st row: Static Controls; 2^nd row: Flex; 3^rd row: Flow; 4^th row: Flex-Flow conditioning; 5^th row: porcine heart valve as Positive control.

<p>Among the experimental groups, CD31-expressing cells were visible within the superficial layers (top and bottom layers) of the engineered tissues, in solely the flex flow group. b) Quantification of positive staining (green; from images in part a) for CD31signal-intensity in four experimental groups; Samples exposed to flex-flow expressed a significantly higher level of positive CD31 (p < 0.05) in comparison to the control group. PHV was treated as the positive control.</p