Raman spectroscopy for postmortem interval estimation of human skeletal remains: A scoping review

Estimating postmortem intervals (PMI) is crucial in forensic investigations, providing insights into criminal cases and determining the time of death. PMI estimation relies on expert experience and a combination of thanatological data and environmental factors but is prone to errors. The lack of reliable methods for assessing PMI in bones and soft tissues necessitates a better understanding of bone decomposition. Several research groups have shown promise in PMI estimation in skeletal remains but lack valid data for forensic cases. Current methods are costly, time-consuming, and unreliable for PMIs over 5 years. Raman spectroscopy (RS) can potentially estimate PMI by studying chemical modifications in bones and teeth correlated with burial time. This review summarizes RS applications, highlighting its potential as an innovative, nondestructive, and fast technique for PMI estimation in forensic medicine.

The 'ForensOMICS' approach for postmortem interval estimation from human bone by integrating metabolomics, lipidomics, and proteomics

The combined use of multiple omics allows to study complex interrelated biological processes in their entirety. We applied a combination of metabolomics, lipidomics and proteomics to human bones to investigate their combined potential to estimate time elapsed since death (i.e., the postmortem interval [PMI]). This 'ForensOMICS' approach has the potential to improve accuracy and precision of PMI estimation of skeletonized human remains, thereby helping forensic investigators to establish the timeline of events surrounding death. Anterior midshaft tibial bone was collected from four female body donors before their placement at the Forensic Anthropology Research Facility owned by the Forensic Anthropological Center at Texas State (FACTS). Bone samples were again collected at selected PMIs (219-790-834-872days). Liquid chromatography mass spectrometry (LC-MS) was used to obtain untargeted metabolomic, lipidomic, and proteomic profiles from the pre- and post-placement bone samples. The three omics blocks were investigated independently by univariate and multivariate analyses, followed by Data Integration Analysis for Biomarker discovery using Latent variable approaches for Omics studies (DIABLO), to identify the reduced number of markers describing postmortem changes and discriminating the individuals based on their PMI. The resulting model showed that pre-placement metabolome, lipidome and proteome profiles were clearly distinguishable from post-placement ones. Metabolites in the pre-placement samples suggested an extinction of the energetic metabolism and a switch towards another source of fuelling (e.g., structural proteins). We were able to identify certain biomolecules with an excellent potential for PMI estimation, predominantly the biomolecules from the metabolomics block. Our findings suggest that, by targeting a combination of compounds with different postmortem stability, in the future we could be able to estimate both short PMIs, by using metabolites and lipids, and longer PMIs, by using proteins.

Analysis of Microbial Community Structure and Diversity in Burial Soil of Yangguanzhai Cemetery

As one of the common physical remains in archaeological discoveries, human bones are important bases for studying the history of human development, which is of great significance for exploring the evolution law of ancient human, reconstructing ancient human society, and tracking the development of human civilization. However, in the process of human bone burial, in addition to being affected by physical and chemical factors, it will also be affected by microorganisms in the buried soil, resulting in a variety of diseases. According to the determination and analysis of the microbial community structure and diversity in the burial soil of Yangguanzhai Site in Gaoling District in Xi’an city, Shaanxi Province, this paper attempts to explore the influence of microorganisms in the burial environment on human bones, in order to provide scientific proof for the microbial prevention and control of bone relics in the archaeological excavation site. For the first time, Illumina NovaSeq high-throughput sequencing technology was used to analyze the microbial community structure in the burial soil. At the phylum level, there were 8 dominant bacteria species in the soil samples of tombs, which were Firmicutes, Actinobacteriota, Actinobacteria, Proteobacteria, Acidobacteriota, Methylomirabilota, Chloroflexi, Bacteroidota. At the genus level, there were 12 dominant species in the soil samples of tombs, including MIZ17, MND1, Gaiella, oc32, Kroppenstedtia, Halomonas, Bacteroides, Dongia, Faecalibacterium, Nocardioides, Pseudomonas, Pseudonocardia. The overall microorganisms in the soil of Yangguanzhai Cemetery were relatively well-distributed, and the microbial community structure near human bones is the most abundant and diverse. Therefore, it is necessary to take some measures to control microorganisms and protect human bones.

Deciphering core proteins of osteoporosis with iron accumulation by proteomics in human bone

Iron accumulation is an independent risk factor for postmenopausal osteoporosis, but mechanistic studies of this phenomenon are still focusing on molecular and genetic researches in model animal. Osteoporosis with iron accumulation is a distinct endocrine disease with complicated pathogenesis regulated by several proteins. However, the comprehensive proteome-wide analysis of human bone is lacking. Using multiplex quantitative tandem mass tag-based proteomics, we detected 2900 and quantified 1150 proteins from bone of 10 postmenopausal patients undergoing hip replacement. Comparing with non-osteoporosis patients, a total of 75 differentially expressed proteins were identified, comprising 53 downregulated proteins and 22 upregulated proteins. These proteins primarily affect oxidoreductase activity, GTPase activity, GTP binding, and neural nucleus development, were mainly enriched in neural, angiogenesis and energy-related pathways, and formed complex regulatory networks with strong interconnections. We ultimately identified 4 core proteins (GSTP1, LAMP2, COPB1, RAB5B) that were significantly differentially expressed in the bone of osteoporosis patients with iron accumulation, and validated the changed protein level in the serum of the medical examination population. Our systemic analysis uncovers molecular insights for revealing underlying mechanism and clinical therapeutics in osteoporosis with iron accumulation.

Osteoinductive effect of soluble transforming growth factor beta receptor 3 on human osteoblast lineage

The development of bone requires carefully choregraphed signaling to bone progenitors to form bone. Our group recently described the requirement of transforming growth factor beta receptor 3 (TGFβR3), a receptor involved in TGFβ pathway signaling, during osteoblast lineage commitment in mice. The TGFβ pathway is known to play multiple osteo-inductive and osteo-inhibitory roles during osteoblast development and TGFβR3 human mutations are associated with reduced bone mineral density, making TGFβR3 a unique target for bone inductive therapy. In this article, we demonstrated increased mineralization of human pediatric bone-derived osteoblast-like cells (HBO) when treated with soluble TGFβR3 (sR3) using Alizarin Red staining. Osteogenic commitment of HBO cells was demonstrated by induction of osteogenic genes RUNX2, osteocalcin, osteopontin, and osterix. Evaluation of the canonical TGFβ pathway signaling demonstrated that sR3 was able to induce bone formation in HBO cells, mainly through activation of noncanonical targets of TGFβ pathway signaling including AKT, ERK, and p38 MAP kinases. Inhibition of these osteogenic noncanonical pathways in the HBO cells also inhibited mineralization, suggesting they are each required. Although no induction of SMAD1, 5, and 9 was observed, there was the activation of SMAD2 and 3 suggesting that sR3 is primarily signaling via the noncanonical pathways during osteogenic induction of the HBO. Our results highlight the important role of TGFβR3 in osteoblast induction of mineralization in human bone cells through noncanonical targets of TGFβ signaling. Future studies will focus on the ability of sR3 to induce bone regeneration in vivo using animal models.

Effects of rotary ultrasonic bone drilling on cutting force and temperature in the human bones

Efficacy and outcomes of osteosynthesis depend on various factors including types of injury and repair, host factors, characteristics of implant materials and type of implantation. One of the most important host factors appears to be the extent of bone damage due to the mechanical force and thermal injury which are produced at cutting site during bone drilling. The temperature above the critical temperature (47 °C) produces thermal osteonecrosis in the bones. In the present work, experimental investigations were performed to determine the effect of drilling parameters (rotational speed, feed rate and drill diameter) and techniques (conventional surgical bone drilling and rotary ultrasonic bone drilling) on cutting force and temperature generated during bone drilling. The drilling experiments were performed by a newly developed bone drilling machine on different types of human bones (femur, tibia and fibula) having different biological structure and mechanical behaviour. The bone samples were procured from male cadavers with the age of second to fourth decades. The results revealed that there was a significant difference (p < 0.05) in cutting force and temperature rise for rotary ultrasonic bone drilling and conventional surgical bone drilling. The cutting force obtained in rotary ultrasonic bone drilling was 30%-40%, whereas temperature generated was 50%-55% lesser than conventional surgical bone drilling process for drilling in all types of bones. It was also found that the cutting force increased with increasing feed rate, drill diameter and decrease in rotational speed, whereas increasing rotational speed, drill diameter and feed rate resulted in higher heat generation during bone drilling. Both the techniques revealed that the axial cutting force and the temperature rise were significantly higher in femur and tibia compared with the fibula for all combinations of process parameters.

Remodelling of human bone on the chorioallantoic membrane of the chicken egg: De novo bone formation and resorption

Traditionally used as an angiogenic assay, the chorioallantoic membrane (CAM) assay of the chick embryo offers significant potential as an in vivo model for xenograft organ culture. Viable human bone can be cultivated on the CAM and increases in bone volume are evident; however, it remains unclear by what mechanism this change occurs and whether this reflects the physiological process of bone remodelling. In this study we tested the hypothesis that CAM-induced bone remodelling is a consequence of host and graft mediated processes. Bone cylinders harvested from femoral heads post surgery were placed on the CAM of green fluorescent protein (GFP)-chick embryos for 9 days, followed by micro computed tomography (μCT) and histological analysis. Three-dimensional registration of consecutive μCT-scans showed newly mineralised tissue in CAM-implanted bone cylinders, as well as new osteoid deposition histologically. Immunohistochemistry demonstrated the presence of bone resorption and formation markers (Cathepsin K, SOX9 and RUNX2) co-localising with GFP staining, expressed by avian cells only. To investigate the role of the human cells in the process of bone formation, decellularised bone cylinders were implanted on the CAM and comparable increases in bone volume were observed, indicating that avian cells were responsible for the bone mineralisation process. Finally, CAM-implantation of acellular collagen sponges, containing bone morphogenetic protein 2, resulted in the deposition of extracellular matrix and tissue mineralisation. These studies indicate that the CAM can respond to osteogenic stimuli and support formation or resorption of implanted human bone, providing a humanised CAM model for regenerative medicine research and a novel short-term in vivo model for tissue engineering and biomaterial testing.

Development and Validation of a Method for the Analysis of Bisoprolol and Atenolol in Human Bone

A method based on gas chromatography–mass spectrometry (GC–MS) is described for the determination of bisoprolol and atenolol in human bone. After the addition of lobivolol as internal standard, pulverized samples were incubated in acetonitrile for 1 h under ultrasounds. After adjusting the pH of the samples to 6, they were centrifuged, and the supernatants were subjected to solid phase extraction. Elution was achieved by using 3 mL of 2% ammonium hydroxide in 80:20 dichloromethane:isopropanol solution. Eluted samples were evaporated and derivatized. Chromatography was performed on a fused silica capillary column and analytes were determined in the selected-ion-monitoring (SIM) mode. The assay was validated in the range 0.1–0.3 ng/mg (depending on the drug) to 150 ng/mg, the mean absolute recoveries were 60% for bisoprolol and 106% for atenolol, the matrix effect was 69% for bisoprolol and 70% for atenolol and process efficiency was 41% for bisoprolol and 80% for atenolol. The intra- and inter-assay accuracy values were always better than 12%. The validated method was then applied to bone samples from two real forensic cases in which toxicological analysis in blood were positive for atenolol in the first case (0.65 µg/mL) and bisoprolol in the second case (0.06 µg/mL). Atenolol was found in bone samples from the corresponding case at the approximate concentration of 148 ng/mg and bisoprolol was found at 8 ng/mg.

Dental pulp stem cells and Bonelike® for bone regeneration in ovine model

Development of synthetic bone substitutes has arisen as a major research interest in the need to find an alternative to autologous bone grafts. Using an ovine model, the present pre-clinical study presents a synthetic bone graft (Bonelike^®) in combination with a cellular system as an alternative for the regeneration of non-critical defects. The association of biomaterials and cell-based therapies is a promising strategy for bone tissue engineering. Mesenchymal stem cells (MSCs) from human dental pulp have demonstrated both in vitro and in vivo to interact with diverse biomaterial systems and promote mineral deposition, aiming at the reconstruction of osseous defects. Moreover, these cells can be found and isolated from many species. Non-critical bone defects were treated with Bonelike^® with or without MSCs obtained from the human dental pulp. Results showed that Bonelike^® and MSCs treated defects showed improved bone regeneration compared with the defects treated with Bonelike^® alone. Also, it was observed that the biomaterial matrix was reabsorbed and gradually replaced by new bone during the healing process. We therefore propose this combination as an efficient binomial strategy that promotes bone growth and vascularization in non-critical bone defects.

Characterization of a submicro-X-ray fluorescence setup on the B16 beamline at Diamond Light Source

An X-ray fluorescence setup has been tested on the B16 beamline at the Diamond Light Source synchrotron with two different excitation energies (12.7 and 17 keV). This setup allows the scanning of thin samples (thicknesses up to several micrometers) with a sub-micrometer resolution (beam size of 500 nm × 600 nm determined with a 50 µm Au wire). Sensitivities and detection limits reaching values of 249 counts s^-1 fg^-1 and 4 ag in 1000 s, respectively (for As Kα excited with 17 keV), are presented in order to demonstrate the capabilities of this setup. Sample measurements of a human bone and a single cell performed at B16 are presented in order to illustrate the suitability of the setup in biological applications.

Evaluation of RNA from human trabecular bone and identification of stable reference genes

The isolation of good quality RNA from tissues is an essential prerequisite for gene expression analysis to study pathophysiological processes. This study evaluated the RNA isolated from human trabecular bone and defined a set of stable reference genes. After pulverization, RNA was extracted with a phenol/chloroform method and then purified using silica columns. The A260/280 ratio, A260/230 ratio, RIN, and ribosomal ratio were measured to evaluate RNA quality and integrity. Moreover, the expression of six candidates was analyzed by qPCR and different algorithms were applied to assess reference gene stability. A good purity and quality of RNA was achieved according to A260/280 and A260/230 ratios, and RIN values. TBP, YWHAZ, and PGK1 were the most stable reference genes that should be used for gene expression analysis. In summary, the method proposed is suitable for gene expression evaluation in human bone and a set of reliable reference genes has been identified.

A microbeam grazing-incidence approach to L-shell x-ray fluorescence measurements of lead concentration in bone and soft tissue phantoms

OBJECTIVE

L-shell x-ray fluorescence (LXRF) is a non-invasive approach to lead (Pb) concentration measurements in the human bone. The first studies were published in the early 1980s. In the same period the K-shell x-ray fluorescence (KXRF) method using a Cd-109 radionuclide source was developed and later improved and refined. Lower sensitivity and calibration difficulties associated with the LXRF method led the KXRF to be the most adopted method for in vivo human bone Pb studies. In the present study a microbeam-based grazing-incidence approach to Pb LXRF measurements was investigated.

APPROACH

The microbeam produced by an integrated x-ray tube and polycapillary x-ray lens (PXL) unit was used to excite cylindrical plaster-of-Paris (poP) bone phantoms doped with Pb in seven concentrations: 0, 8, 16, 29, 44, 59, and 74 µg g-1. Two 1 mm- and 3 mm-thick cylindrical shell soft tissue phantoms were made out of polyoxymethylene (POM) plastic. Three bone-soft tissue phantom sets corresponding to the 0, 1, and 3 mm POM thickness values resulted. Each phantom was placed between the microbeam and the detector; its position was controlled using a positioning stage. Small steps (0.1-0.5 mm) and short 30 s x-ray spectra acquisitions were used to find the optimal phantom position according to the maximum observed Sr Kα peak height. At the optimal geometry, five 180 s x-ray spectra were acquired for each phantom set. Calibration lines were obtained using the fitted peak heights of the two observed Pb Lα and Pb Lβ peaks.

MAIN RESULTS

The lowest detection limit (DL) values were (2.9  ±  0.2), (4.9  ±  0.3), and (23  ±  3) µg g-1, respectively. The order of magnitude of the absorbed radiation dose in the POM plastic for the 180 s irradiation was estimated to be  <1 mGy.

SIGNIFICANCE

The results are superior to a relatively recently published LXRF phantom study and show promise for future designs of in vivo LXRF measurements.

TGF-β Signaling Accelerates Senescence of Human Bone-Derived CD271 and SSEA-4 Double-Positive Mesenchymal Stromal Cells

It is generally thought that the proliferative capacity and differentiation potential of somatic stem cells, including mesenchymal stromal/stem cells (MSCs) and hematopoietic stem cells, decline with age. We investigated the effects of aging on human bone-derived MSCs expressing CD271 and SSEA-4 (double-positive MSCs [DPMSCs]). The percentages of DPMSCs in bone tissue decreased significantly with age. The DPMSCs from elderly patients (old DPMSCs) showed cellular senescence, which was evidenced by low growth potential, high senescence-associated β-galactosidase activity, and elevated p16 and p21 CDK inhibitor levels. Moreover, old DPMSCs showed weak osteogenic differentiation potential and less hematopoiesis-supporting activity in comparison with young DPMSCs. Interestingly, the addition of transforming growth factor β2 (TGF-β2) induced cellular senescence in young DPMSCs. With the exception of the adipogenic differentiation potential, all of the aging phenomena observed in old DPMSCs were reversed by the addition of anti-TGF-β antibodies. These results suggest that, in part, old DPMSCs accelerate cellular senescence through TGF-β signaling.

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The percentages of CD271⁺SSEA-4⁺ MSCs (DPMSCs) in bone tissue decline with age

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DPMSCs may accelerate cellular senescence through TGF-β2

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TGF-β can change the balance of adipogenesis and osteogenesis of DPMSCs

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The aging phenomena can possibly be reversed by anti-TGF-β antibodies

Scanning Electron Microscope (SEM) Evaluation of the Interface between a Nanostructured Calcium-Incorporated Dental Implant Surface and the Human Bone

Purpose. The aim of this scanning electron microscope (SEM) study was to investigate the interface between the bone and a novel nanostructured calcium-incorporated dental implant surface in humans. Methods. A dental implant (Anyridge^®, Megagen Implant Co., Gyeongbuk, South Korea) with a nanostructured calcium-incorporated surface (Xpeed^®, Megagen Implant Co., Gyeongbuk, South Korea), which had been placed a month earlier in a fully healed site of the posterior maxilla (#14) of a 48-year-old female patient, and which had been subjected to immediate functional loading, was removed after a traumatic injury. Despite the violent trauma that caused mobilization of the fixture, its surface appeared to be covered by a firmly attached, intact tissue; therefore, it was subjected to SEM examination. The implant surface of an unused nanostructured calcium-incorporated implant was also observed under SEM, as control. Results. The surface of the unused implant showed a highly-structured texture, carved by irregular, multi-scale hollows reminiscent of a fractal structure. It appeared perfectly clean and devoid of any contamination. The human specimen showed trabecular bone firmly anchored to the implant surface, bridging the screw threads and filling the spaces among them. Conclusions. Within the limits of this human histological report, the sample analyzed showed that the nanostructured calcium-incorporated surface was covered by new bone, one month after placement in the posterior maxilla, under an immediate functional loading protocol.

Synchrotron radiation micro X-ray fluorescence spectroscopy of thin structures in bone samples: comparison of confocal and color X-ray camera setups

In the quest for finding the ideal synchrotron-radiation-induced imaging method for the investigation of trace element distributions in human bone samples, experiments were performed using both a scanning confocal synchrotron radiation micro X-ray fluorescence (SR-µXRF) (FLUO beamline at ANKA) setup and a full-field color X-ray camera (BAMline at BESSY-II) setup. As zinc is a trace element of special interest in bone, the setups were optimized for its detection. The setups were compared with respect to count rate, required measurement time and spatial resolution. It was demonstrated that the ideal method depends on the element of interest. Although for Ca (a major constituent of the bone with a low energy of 3.69 keV for its Kα XRF line) the color X-ray camera provided a higher resolution in the plane, for Zn (a trace element in bone) only the confocal SR-µXRF setup was able to sufficiently image the distribution.

The role of the collaborative functions of the composite structure of organic and inorganic constituents and their influence on the electrical properties of human bone

BACKGROUND

The electrical potential, which is generated in bone by collagen displacement, has been well documented. However, the role of mineral crystals in bone piezoelectricity has not yet been elucidated.

OBJECTIVE

We examined the mechanism that the composite structure of organic and inorganic constituents and their collaborative functions play an important role in the electrical properties of human bone.

METHODS

The electrical potential and bone structure were evaluated using thermally stimulated depolarized current (TSDC) and micro computed tomography, respectively. After electrical polarization of bone specimens, the stored electrical charge was calculated using TSDC measurements. The CO3/PO4 peak ratio was calculated using attenuated total reflection to compare the content of carbonate ion in the bone specimens.

RESULTS

The TSDC curve contained 3 peaks at 100, 300 and 500°C, which were classified into 4 patterns. The CO3/PO4 peak ratio positively correlated with the stored charges at approximately 300°C in the polarized bone. There was a positive correlation between the stored bone charge and the bone mineral density only.

CONCLUSIONS

It is suggested that the peak at 300°C is attributed to carbonate apatite and the total bone mass of human bone, not the three-dimensional structure, affects the stored charge.

Assessment of chemical species of lead accumulated in tidemarks of human articular cartilage by X-ray absorption near-edge structure analysis

A highly specific accumulation of the toxic element lead was recently measured in the transition zone between non-calcified and calcified normal human articular cartilage. This transition zone, the so-called `tidemark', is considered to be an active calcification front of great clinical importance. However, little is known about the mechanisms of accumulation and the chemical form of Pb in calcified cartilage and bone. Using spatially resolved X-ray absorption near-edge structure analysis (µ-XANES) at the Pb L(3)-edge, the chemical state of Pb in the osteochondral region was investigated. The feasibility of the µ-XANES set-up at the SUL-X beamline (ANKA synchrotron light source) was tested and confirmed by comparing XANES spectra of bulk Pb-reference compounds recorded at both the XAS and the SUL-X beamline at ANKA. The µ-XANES set-up was then used to investigate the tidemark region of human bone (two patella samples and one femoral head sample). The spectra recorded at the tidemark and at the trabecular bone were found to be highly correlated with the spectra of synthetic Pb-doped carbonated hydroxyapatite, suggesting that in both of these very different tissues Pb is incorporated into the hydroxyapatite structure.

The influence of mechanical stimulation on osteocyte apoptosis and bone viability in human trabecular bone

It has been shown previously using in vivo and ex vivo animal models, that cyclical mechanical stimulation is capable of maintaining osteocyte viability through the control of apoptotic cell death. Here we have studied the effect of mechanical stimulation on osteocyte viability in human trabecular bone maintained in a 3-D bioreactor system. Bone samples, maintained in the bioreactor system for periods of 3, 7 and 27 days, were subjected to either cyclical mechanical stimulation which engendered a maximum of 3,000 microstrain in a waveform corresponding to physiological jumping exercise for 5 minutes daily or control unloading. Unloading resulted in a decrease in osteocyte viability within 3 days that was accompanied by increased levels of cellular apoptosis. Mechanical stimulation significantly reduced apoptosis (p< or =0.032) and improved the maintenance of osteocyte viability in bone from all patient samples. The percentage Alkaline Phosphatase (ALP) labelled bone surface was significantly increased (p< or =0.05) in response to mechanical stimulation in all samples as was the Bone Formation Rate (BFR/BS) (p=0.005) as determined by calcein label incorporation in the 27-day experiment. These data indicate that in this model system, mechanical stimulation is capable of maintaining osteocyte viability in human bone.

Genetic Markers in Human Bone Tissue

The use of genetic markers in bone and tissues as a method of human identification is reviewed in detail. Methods for the identification of human remains and the case situations requiring them are described. Some of the previous work on tissue and bone ABO grouping from both anthropological and medicolegal perspectives is reviewed; and some results from our own studies that have produced a highly reliable bone grouping procedure are presented. Some of our work and that of others on the typing of other classical genetic marker systems in bone is included. Recent work on DNA polymorphism typing and some actual and potential forensic applications of bone (and tissue) deoxyribonucleic acid (DNA) typing are discussed.