The characterisation of pluripotent and multipotent stem cells using Fourier transform infrared microspectroscopy

Synchrotron Infrared Microspectroscopy for Stem Cell Research

Stem cells have shown great potential functions for tissue regeneration and repair because of their unlimited self-renewal and differentiation. Stem cells reside in their niches, making them a hotspot for the development and diagnosis of diseases. Complex interactions between niches and stem cells create the balance between differentiation, self-renewal, maturation, and proliferation. However, the multi-facet applications of stem cells have been challenged since the complicated responses of stem cells to biological processes were explored along with the limitations of current systems or methods. Emerging evidence highlights that synchrotron infrared microspectroscopy, known as synchrotron radiation-based Fourier transform infrared microspectroscopy, has been investigated as a potentially attractive technology with its non-invasive and non-biological probes in stem cell research. With their unique vibration bands, the quantitative mapping of the content and distribution of biomolecules can be detected and characterized in cells or tissues. In this review, we focus on the potential applications of synchrotron infrared microspectroscopy for investigating the differentiation and fate determination of stem cells.

Utilization of Modified Induced Pluripotent Stem Cells as the Advance Therapy of Glaucoma: A Systematic Review

Glaucoma is an optic neuropathy disease that causes cupping of the optic disc and decreased visual field. Glaucoma is still the second leading cause of blindness globally, with a worldwide prevalence of more than 76 million people in 2020. However, no therapy can cure glaucoma completely, especially when optic nerve damage has occurred. Available treatments only play a role in keeping the intraocular pressure stable This research aims to determine the potential use of modified stem cell therapy to treat intraocular damage in glaucoma cases. Literature research was conducted by involving seven online databases, namely Pubmed, ScienceDirect^®, Proquest, EBSCOhost^®, SAGE^®, Clinicalkey^®, and Scopus, published between 2010–2020 with the keywords stem cells; therapy; glaucoma; optic nerve. Six articles were selected, and out of the six articles, all writings were experimental research. The entire literature states that modified stem cell therapy has the potential as a therapeutic option in treating intraocular damage in patients with glaucoma. Based on the systematic literature review that has been carried out, it is known that stem cell therapy has the potential to be a therapeutic option in treating glaucoma cases. Much more research is needed to assess the effectiveness of modified stem cell therapy in managing intraocular damage due to glaucoma.

Enhanced Magnetic Hyperthermia of Magnetoferritin through Synthesis at Elevated Temperature

Iron oxide nanoparticles have attracted a great deal of research interest in recent years for magnetic hyperthermia therapy owing to their biocompatibility and superior thermal conversion efficiency. Magnetoferritin is a type of biomimetic superparamagnetic iron oxide nanoparticle in a ferritin cage with good monodispersity, biocompatibility, and natural hydrophilicity. However, the magnetic hyperthermic efficiency of this kind of nanoparticle is limited by the small size of the mineral core as well as its low synthesis temperature. Here, we synthesized a novel magnetoferritin particle by using a recombinant ferritin from the hyperthermophilic archaeon Pyrococcus furiosus as a template with high iron atom loading of 9517 under a designated temperature of 90 °C. Compared with the magnetoferritins synthesized at 45 and 65 °C, the one synthesized at 90 °C displays a larger average magnetite and/or maghemite core size of 10.3 nm. This yields an increased saturation magnetization of up to 49.6 emu g⁻¹ and an enhanced specific absorption rate (SAR) of 805.3 W g⁻¹ in an alternating magnetic field of 485.7 kHz and 49 kA m⁻¹. The maximum intrinsic loss power (ILP) value is 1.36 nHm² kg⁻¹. These results provide new insights into the biomimetic synthesis of magnetoferritins with enhanced hyperthermic efficiency and demonstrate the potential application of magnetoferritin in the magnetic hyperthermia of tumors.

First Identification of the Effects of Low Frequency Electromagnetic Field on the Micromolecular Changes in Adipose Tissue-Derived Mesenchymal Stem Cells by Fourier Transform Infrared Spectroscopy

Purpose:

In this study, we hypothesize that exposure of adipose tissue-mesenchymal stem cells (AT-MSCs) to electromagnetic field (EMF) may impact adipose stem cells' micromolecular structure (analyzed using Fourier transform infrared spectroscopy [FTIR]).

Materials and Methods:

The AT-MSCs were exposed to continuous vertically applied sinusoidal EMF with a frequency of 50 Hz and a flux density of 1.5 mT for 24, 48, and 72 h. After an appropriate time (24, 48, 72 h) cells were washed with PBS, scrubbed, and immediately taken into FTIR analyses.

Results:

EMFs affect AT-MSCs. The greatest differences were in the range of nucleic acids and proteins in the fingerprint region which occurred after 24 and 48 h of EMF exposure. However, in the case of 72 h of EMF exposure, no significant differences were noticed in the FTIR spectra towards the control.

Conclusions:

FTIR spectra show differences between samples under the influence of EMF before they will be manifested at the morphological level. The largest differences in the range of nucleic acids and proteins in the fingerprint region occurred at 24 and 48 h of EMF exposure. That means it was during the first 48 h after EMF exposure a great number of dynamic changes occurred. However, in the case of AT-MSCs in 72 h EMF and 72 h control, no significant differences were noted in the FTIR spectra, which means that the chemical composition in these two cases is similar. EMF is not neutral for stem cells, especially in the in the first hours of interaction (24 h, 48 h).

The effect of extracellular matrix on the differentiation of mouse embryonic stem cells

Embryonic stem cells (ESCs) are promising research materials to investigate cell fate determination since they have the capability to differentiate. Stem cell differentiation has been extensively studied with various microenvironment mimicking structures to modify cellular dynamics associated with the cell-extracellular matrix (ECM) interactions and cell-cell communications. In the current study, our aim was to determine the effect of microenvironmental proteins with different concentrations on the capacity and differentiation capability of mouse ESCs (mESCs), combining the biochemical assays, imaging techniques, Fourier transform infrared (FTIR) spectroscopy, and unsupervised multivariate analysis. Based on our data, coating the surface of mESCs with Matrigel, used as an acellular matrix substrate, resulted in morphological and biochemical changes. mESCs exhibited alterations in their phenotype after growing on the Matrigel-coated surfaces, including their differentiation capacity, cell cycle phase pattern, membrane fluidity, and metabolic activities. In conclusion, mESCs can be stimulated physiologically, chemically, or mechanically to convert them a new phenotype. Thus, identification of ESCs' behavior in the acellular microenvironment could be vital to elucidate the mechanism of diseases. It might also be promising to control the cell fate in the field of tissue engineering.

The Effects of Cordyceps sinensis (Berk.) Sacc. and Gymnema inodorum (Lour.) Decne. Extracts on Adipogenesis and Lipase Activity In Vitro

This study aimed to investigate the effects of Cordyceps sinensis extract (CSE) and Gymnema inodorum extract (GIE), used alone and combined, on antiadipogenesis in 3T3-L1 cells. Oil Red O staining was used to examine the effects of these extracts on inhibition of intracellular lipid accumulation in 3T3-L1 adipocytes and on lipid droplet morphology. Fourier transform-infrared (FTIR) microspectroscopy was used to examine biomolecular changes in 3T3-L1 adipocytes. The pancreatic lipase assay was used to evaluate the inhibitory effects of CSE and GIE on pancreatic lipase activity. Taken together, the results indicated that CSE, GIE, and their combination suppressed lipid accumulation. The FTIR microspectroscopy results indicated that CSE, GIE, and their combination had inhibitory effects on lipid accumulation in the adipocytes. Compared with the untreated adipocytes, the signal intensity and integrated areas of glycogen and other carbohydrates, the acyl chain of phospholipids, and the lipid/protein ratios of the CSE, GIE, alone, and combined treated adipocytes were significantly lower (p < 0.05). Combination treatment resulted in a synergistic effect on lipid accumulation reduction in the adipocytes. Principal component analysis of the biomolecular changes revealed six distinct clusters in the FTIR spectra of the sample cells. The pancreatic lipase assay results indicated that CSE and GIE inhibited the pancreatic lipase activity in a dose-dependent manner (mean ± standard error of the mean IC₅₀ values, 2312.44 ± 176.55 μg mL⁻¹ and 982.24 ± 44.40 μg mL⁻¹, resp.). Our findings indicated that FTIR microspectroscopy has potential application for evaluation of the effectiveness of medicinal plants and for the development of infrared biochemical obesity markers useful for treating patients with obesity. These results suggested that use of CSE and GIE alone and in combination may be efficacious as a complementary therapy for hyperlipidemia and obesity management. However, clinical trials in animals and humans must first be completed.

Characterization of CD133+/CD44+ human prostate cancer stem cells with ATR-FTIR spectroscopy

Current cancer treatments destroy the tumor mass but cannot prevent the recurrence of cancer. The heterogeneous structure of the tumor mass includes cancer stem cells that are responsible for tumor relapse, treatment resistance, invasion and metastasis. The biology of these cells is still not fully understood; therefore, effective treatments cannot be developed sufficiently. Herein, attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, combined with unsupervised multivariate analysis, was applied to prostate cancer stem cells (CSCs), non-stem cancer cells (non-CSCs) and normal prostate epithelial cells to elucidate the molecular mechanisms and features of CSCs, which are crucial to improving the target specific therapies. This work revealed the spectral differences in the cellular mechanisms and biochemical structures among three different cell types. Particularly, prostate CSCs exhibit differences in the lipid composition and dynamics when compared to other cell types. CSCs also harbor pronounced differences in their major cellular macromolecules, including differences in the protein amount and content (mainly α-helices), the abundance of nucleic acids (DNA/RNA), altered nucleic acid conformation and carbohydrate composition. Interestingly, macromolecules containing the C[double bond, length as m-dash]O groups and negatively charged molecules having the COO^- groups are abundant in prostate CSCs in comparison to prostate non-CSCs and normal prostate cells. Overall, this study demonstrates the potential use of ATR-FTIR spectroscopy as a powerful tool to obtain new insights into the understanding of the CSC features, which may provide new strategies for cancer treatment by selectively targeting the CSCs.

The Effect of Pluchea indica (L.) Less. Tea on Adipogenesis in 3T3-L1 Adipocytes and Lipase Activity

Obesity and hyperlipidemia are a major problem in the world. Pluchea indica (L.) Less. tea (PIT) is a beverage that has various indications. This study focused on the effect of the PIT on inhibiting adipogenesis of 3T3-L1 cells and pancreatic lipase enzyme activity. The viability of 3T3-L1 cells was not significantly decreased after exposure to 200 to 1000 μg mL-1 PIT compared to controls (p > 0.05). The PIT at 750 to 1000 μg mL-1 exhibited a significantly reduced lipid accumulation compared to the control (p < 0.05). The inhibitory effects of the PIT at 250 to 1000 μg mL-1 on lipase activity were significantly increased compared to control (p < 0.05). The FTIR results showed that the integrated areas of lipids, proteins, nucleic acids, glycogen, and carbohydrates of the PIT-treated 3T3-L1 adipocytes were significantly lower than the untreated 3T3-L1 adipocytes (p < 0.05). These findings may indicate that the PIT is not only capable of inhibiting lipids and carbohydrate accumulation in adipocytes but also has a potential to inhibit pancreatic lipase activity. So, the PIT may be further developed to the novel lipid-lowering herbal supplement for the management of overweight or obesity.

Oroxylum indicum (L.) Kurz extract inhibits adipogenesis and lipase activity in vitro

Background

Oroxylum indicum (L.) Kurz (O. indicum) is found in Thailand. It has been used for the treatment of obesity. This study aimed to investigate the effects of an O. indicum extract (OIE) on the adipogenic and biomolecular change in 3T3-L1 adipocytes.

Methods

Initial studies examined the chemical components of OIE. The cell line 3T3-L1 was used to establish potential toxic effects of OIE during the differentiation of pre-adipocytes to adipocytes. The inhibitory effect of OIE on lipid accumulation in 3T3-L1 cells was investigated. Moreover, the impact of OIE on pancreatic lipase activity was determined. In further experiments, Fourier Transform Infrared (FTIR) was used to monitor and discriminate biomolecular changes caused by the potential anti-adipogenic effect of OIE on 3T3-L1 cells.

Results

Chemical screening methods indicated that OIE was composed of flavonoids, alkaloids, steroids, glycosides, and tannins. The percentage viability of 3T3-L1 cells was not significantly decreased after exposure to either 200 or 150 μg/mL of OIE for 2 and 10 days, respectively compared to control cells. The OIE exhibited a dose-dependent reduction of lipid accumulation compared to the control (p < 0.05). The extract also demonstrated a dose-dependent inhibitory effect upon lipase activity compared to the control. The inhibitory effect of the OIE on lipid accumulation in 3T3-L1 cells was also confirmed using FTIR microspectroscopy. The signal intensity and the integrated areas relating to lipids, lipid esters, nucleic acids, glycogen and carbohydrates of the OIE-treated 3T3-L1 adipocytes were significantly lower than the non-treated 3T3-L1 adipocytes (p < 0.05). Principal component analysis (PCA) indicated four distinct clusters for the FTIR spectra of 3T3-L1 adipocytes based on biomolecular changes (lipids, proteins, nucleic acids, and carbohydrates). This observation was confirmed using Unsupervised hierarchical cluster analysis (UHCA).

Conclusions

These novel findings provide evidence that the OIE derived from the fruit pods of the plant is capable of inhibiting lipid and carbohydrate accumulation in adipocytes and also has the potential to inhibit an enzyme associated with fat absorption. The initial observations indicate that OIE may have important properties which in the future may be exploited for the management of the overweight or obese.

Biochemical profiling of rat embryonic stem cells grown on electrospun polyester fibers using synchrotron infrared microspectroscopy

Therapeutic options for spinal cord injuries are severely limited; current treatments only offer symptomatic relief and rehabilitation focused on educating the individual on how to adapt to their new situation to make best possible use of their remaining function. Thus, new approaches are needed, and interest in the development of effective strategies to promote the repair of neural tracts in the central nervous system inspired us to prepare functional and highly anisotropic polymer scaffolds. In this work, an initial assessment of the behavior of rat neural progenitor cells (NPCs) seeded on poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) fiber scaffolds using synchrotron-based infrared microspectroscopy (SIRMS) is described. Combined with a modified touch imprint cytology sample preparation method, this application of SIRMS enabled the biochemical profiles of NPCs on the coated polymer fibers to be determined. The results showed that changes in the lipid and amide I–II spectral regions are modulated by the type and coating of the substrate used and the culture time. SIRMS studies can provide valuable insight into the early-stage response of NPCs to the morphology and surface chemistry of a biomaterial, and could therefore be a useful tool in the preparation and optimization of cellular scaffolds.

Graphical abstract

Morphological, molecular and FTIR spectroscopic analysis during the differentiation of kidney cells from pluripotent stem cells

Background

Kidney diseases are a global health problem. Currently, over 2 million people require dialysis or transplant which are associated with high morbidity and mortality; therefore, new researches focused on regenerative medicine have been developed, including the use of stem cells.

Results

In this research, we generate differentiated kidney cells (DKCs) from mouse pluripotent stem cells (mPSCs) analyzing their morphological, genetic, phenotypic, and spectroscopic characteristics along differentiation, highlighting that there are no reports of the use of Fourier transform infrared (FTIR) spectroscopy to characterize the directed differentiation of mPSCs to DKCs. The genetic and protein experiments proved the obtention of DKCs that passed through the chronological stages of embryonic kidney development. Regarding vibrational spectroscopy analysis by FTIR, bands related with biomolecules were shown on mPSCs and DKCs spectra, observing distinct differences between cell lineages and maturation stages. The second derivative of DKCs spectra showed changes in the protein bands compared to mPSCs. Finally, the principal components analysis obtained from FTIR spectra allowed to characterize chemical and structurally mPSCs and their differentiation process to DKCs in a rapid and non-invasive way.

Conclusion

Our results indicated that we obtained DKCs from mPSCs, which passed through the chronological stages of embryonic kidney development. Moreover, FTIR spectroscopy resulted in a non-invasive, rapid and precise technic that together with principal component analysis allows to characterize chemical and structurally both kind of cells and also discriminate and determine different stages along the cell differentiation process.

Classification of Gemcitabine resistant Cholangiocarcinoma cell lines using synchrotron FTIR microspectroscopy

Cholangiocarcinoma (CCA), a cancer of bile duct epithelium, is a major health problem in Thailand especially in the northeast. Overall treatment outcomes have not shown much improvement because the disease is usually detected at an advanced stage and often shows chemotherapeutic resistance. High-throughput Fourier Transform Infrared (FTIR) microspectroscopy can be used for cell classification and has the potential to diagnose cancer and possibly predict chemo-response. This study was aimed to differentiate gemcitabine-sensitive and gemcitabine-resistant induction in two CCA cell lines (KKU-M139 and KKU-M214) and xenograft tissues using synchrotron-FTIR microspectroscopy. Partial Least Squares Discriminant Analysis (PLS-DA) could discriminate between chemo-sensitive and chemo-resistant cells in the FTIR fingerprint spectral region (1800-1000 cm^-1 ) with more than 90% sensitivity and specificity. The chemo-resistant and chemo-sensitive phenotypes were different in protein (amide I, amide II), lipids (carbonyl group and CH₃ deformation) and phosphodiester from nucleic acids. Additionally, spectra from xenograft tissues showed similar results to the cell line study with marked differences between chemo-resistant and chemo-sensitive CCA tissues, and PLS-DA could discriminate the chemotherapeutic response with 98% sensitivity and specificity. This is the first study to demonstrate the use of FTIR microspectroscopy to assess chemo-response both in vitro and in vivo.

Characterization of postmortem biochemical changes in rabbit plasma using ATR-FTIR combined with chemometrics: A preliminary study

Postmortem interval (PMI) determination is one of the most challenging tasks in forensic medicine due to a lack of accurate and reliable methods. It is especially difficult for late PMI determination. Although many attempts with various types of body fluids based on chemical methods have been made to solve this problem, few investigations are focused on blood samples. In this study, we employed an attenuated total reflection (ATR)-Fourier transform infrared (FTIR) technique coupled with principle component analysis (PCA) to monitor biochemical changes in rabbit plasma with increasing PMI. Partial least square (PLS) model was used based on the spectral data for PMI prediction in an independent sample set. Our results revealed that postmortem chemical changes in compositions of the plasma were time-dependent, and various components including proteins, lipids and nucleic acids contributed to the discrimination of the samples at different time points. A satisfactory prediction within 48h postmortem was performed by the combined PLS model with a good fitting between actual and predicted PMI of 0.984 and with an error of ±1.92h. In consideration of the simplicity and portability of ATR-FTIR, our preliminary study provides an experimental and theoretical basis for application of this technique in forensic practice.

FTIR Spectroscopic and Molecular Analysis during Differentiation of Pluripotent Stem Cells to Pancreatic Cells

Some of the greatest challenges in stem cells (SCs) biology and regenerative medicine are differentiation control of SCs and ensuring the purity of differentiated cells. In this work, we differentiated mouse pluripotent stem cells (mPSCs) toward pancreatic cells characterizing this differentiation process by molecular and spectroscopic technics. Both mPSCs and Differentiated Pancreatic Cells (DPCs) were subjected to a genetic, phenotypic, and biochemical analysis by real-time quantitative PCR (RT-qPCR), immunocytochemistry, and Fourier Transform Infrared (FTIR) spectroscopy. Cultured mPCSs expressed pluripotent genes and proteins (Nanog and SOX2). DPCs expressed endodermal genes (SOX17 and Pdx1) at day 11, an inductor gene of embryonic pancreas development (Pdx1) at day 17 and pancreas genes and proteins (Insulin and Glucagon) at day 21 of differentiation. Likewise, FTIR spectra of mPSCs and DPCs at different maturation stages (11, 17, and 21 days) were obtained and showed absorption bands related with different types of biomolecules. These FTIR spectra exhibited significant spectral changes agreeing with the differentiation process, particularly in proteins and nucleic acids bands. In conclusion, the obtained DPCs passed through the chronological stages of embryonic pancreas development and FTIR spectra provide a new biophysical parameter based on molecular markers indicating the differentiation process of mPSCs to specialized cells.

Vibrational spectroscopic methods for cytology and cellular research

The use of vibrational spectroscopy, FTIR and Raman, for cytology and cellular research has the potential to revolutionise the approach to cellular analysis. Vibrational spectroscopy is non-destructive, simple to operate and provides direct information. Importantly it does not require expensive exogenous labels that may affect the chemistry of the cell under analysis. In addition, the advent of spectroscopic microscopes provides the ability to image cells and acquire spectra with a subcellular resolution. This introductory review focuses on recent developments within this fast paced field and highlights potential for the future use of FTIR and Raman spectroscopy. We particularly focus on the development of live cell research and the new technologies and methodologies that have enabled this.

Cellular injury evidenced by impedance technology and infrared microspectroscopy

Fourier Transform Infrared (FTIR) spectroscopy is finding increasing biological application, for example in the analysis of diseased tissues and cells, cell cycle studies and investigating the mechanisms of action of anticancer drugs. Cancer treatment studies routinely define the types of cell-drug responses as either total cell destruction by the drug (all cells die), moderate damage (cell deterioration where some cells survive) or reversible cell cycle arrest (cytostasis). In this study the loss of viability and related chemical stress experienced by cells treated with the medicinal plant, Plectranthus ciliatus, was investigated using real time cell electronic sensing (RT-CES) technology and FTIR microspectroscopy. The use of plants as medicines is well established and ethnobotany has proven that crude extracts can serve as treatments against various ailments. The aim of this study was to determine whether FTIR microspectroscopy would successfully distinguish between different types of cellular injury induced by a potentially anticancerous plant extract. Cervical adenocarcinoma (HeLa) cells were treated with a crude extract of Pciliatus and cells monitored using RT-CES to characterize the type of cellular responses induced. Cell populations were then investigated using FTIR microspectroscopy and statistically analysed using One-way Analysis of Variance (ANOVA) and Principal Component Analysis (PCA). The plant extract and a cancer drug control (actinomycin D) induced concentration dependent cellular responses ranging from nontoxic, cytostatic or cytotoxic. Thirteen spectral peaks (915cm(-)(1), 933cm(-)(1), 989cm(-)(1), 1192cm(-)(1), 1369cm(-)(1), 1437cm(-)(1), 1450cm(-)(1), 1546cm(-)(1), 1634cm(-)(1), 1679cm(-)(1) 1772cm(-)(1), 2874cm(-)(1) and 2962cm(-)(1)) associated with cytotoxicity were significantly (p value<0.05, one way ANOVA, Tukey test, Bonferroni) altered, while two of the bands were also indicative of early stress related responses. In PCA, poor separation between nontoxic and cytostatic responses was evident while clear separation was linked to cytotoxicity. RT-CES detected morphological changes as indicators of cell injury and could distinguish between viable, cytostatic and cytotoxic responses. FTIR microspectroscopy confirmed that cytostatic cells were viable and could still recover while also describing early cellular stress related responses on a molecular level.

FTIR metabolomic fingerprint reveals different modes of action exerted by structural variants of N-alkyltropinium bromide surfactants on Escherichia coli and Listeria innocua cells

Surfactants are extremely important agents to clean and sanitize various environments. Their biocidal activity is a key factor determined by the interactions between amphiphile structure and the target microbial cells. The object of this study was to analyze the interactions between four structural variants of N-alkyltropinium bromide surfactants with the Gram negative Escherichia coli and the Gram positive Listeria innocua bacteria. Microbiological and conductometric methods with a previously described FTIR bioassay were used to assess the metabolomic damage exerted by these compounds. All surfactants tested showed more biocidal activity in L. innocua than in E. coli. N-tetradecyltropinium bromide was the most effective compound against both species, while all the other variants had a reduced efficacy as biocides, mainly against E. coli cells. In general, the most prominent metabolomic response was observed for the constituents of the cell envelope in the fatty acids (W1) and amides (W2) regions and at the wavenumbers referred to peptidoglycan (W2 and W3 regions). This response was particularly strong and negative in L. innocua, when cells were challenged by N-tetradecyltropinium bromide, and by the variant with a smaller head and a 12C tail (N-dodecylquinuclidinium bromide). Tail length was critical for microbial inhibition especially when acting against E. coli, maybe due the complex nature of Gram negative cell envelope. Statistical analysis allowed us to correlate the induced mortality with the metabolomic cell response, highlighting two different modes of action. In general, gaining insights in the interactions between fine structural properties of surfactants and the microbial diversity can allow tailoring these compounds for the various operative conditions.

Histologic and spectroscopic study of pluripotent stem cells after implant in ocular traumatic injuries in a murine model

Introduction

Ocular trauma is defined as a trauma caused by blunt or penetrating mechanisms on the eyeball and its peripheral structures, causing damage with different degrees of affection with temporary or permanent visual function compromise. Ocular trauma is a major cause of preventable blindness worldwide; it constitutes 7% of all corporal injury and 10% to 15% of all eye diseases. Regenerative medicine research has opened up the possibility to use stem cells as a source of cell replacement, so that experimental studies on embryonic stem cells and bone marrow stem cells have been carried out. In this study, we analyzed the histopathological and spectroscopic changes in ocular tissue with trauma, treated with mouse pluripotent stem cells.

Methods

Firstly, mouse embryonic stem cells were seeded. Subsequently, the obtained cells were implanted in a murine model of scleral and retinal damage at the first, second, and fourth weeks post-trauma. At week 12 post-trauma, the eyes were enucleated for histopathologic study (inflammatory response and histological integrity) and spectroscopic analysis by Fourier transform infrared spectroscopy in the attenuated total reflection configuration. Data were analyzed by one-way analysis of variance.

Results

Histopathological results showed that the experimental groups treated with stem cells presented a decrease in the inflammatory response, and the histological integrity was restored, which contrasted with the experimental group treated with saline solution. Moreover, in the spectroscopic analysis, characteristic bands of biological samples were observed in all tissues, highlighting in healthy tissues the presence of C = O bond at 1,745 cm^-1, which was not observed in the injured and treated tissues. Also, the absorption spectrum of the tissues treated with embryonic stem cells showed bands whose intensity was high at around 1,080 to 1,070 cm^-1. It has been reported that these bands are characteristic of pluripotent stem cells.

Conclusions

The implant of embryonic stem cells could be a useful therapeutic treatment after traumatic eye injuries or many other eye diseases to reduce the inflammatory response and restore histological integrity. Furthermore, the spectroscopic technique could be used as a complementary technique for detecting stem cell incorporation into various tissues.

Label-free identification of the glioma stem-like cell fraction using Fourier-transform infrared spectroscopy

PURPOSE

Vibrational spectroscopy enables the label-free characterization of cells and tissue by probing the biochemical composition. Here, we evaluated these techniques to identify glioblastoma stem cells.

MATERIALS AND METHODS

The biochemical fingerprints of glioblastoma cells were established in human cell lines with high and low content of CD133 (cluster of differentiation 133)-positive cells using attenuated total reflection Fourier-transform infrared (ATR FT-IR) on vital cells and FT-IR mapping, which delivers spatially resolved spectroscopic datasets. After data preprocessing, unsupervised cluster analysis was applied. CD133 was addressed with flow cytometry and immunohistochemistry and used as a stemness marker.

RESULTS

In all preparations, the algorithm was able to correctly classify the spectra, differentiating CD133-rich and -poor populations. The main spectral differences were found in the region of 1000 cm(- 1) to 1150 cm(- 1) that can be assigned to vibrations of chemical bonds of DNA, RNA, carbohydrates and phospholipids. Interestingly, this spectral region is a key feature to discern glioblastoma from normal brain parenchyma, as FT-IR spectroscopic mapping of experimental brain tumors demonstrated.

CONCLUSIONS

We were able to show biochemical differences between glioblastoma cell populations with high and low content of cancer stem cells that are presumably related to changes in the RNA/DNA content.