Assessment of tobacco heating system 2.4 on osteogenic differentiation of mesenchymal stem cells and primary human osteoblasts compared to conventional cigarettes

A scoping review of the toxicity and health impact of IQOS

This work aims to summarize the current evidence on the toxicity and health impact of IQOS, taking into consideration the data source. On 1 June 2022, we searched PubMed, Web of Science, and Scopus databases using the terms: 'heated tobacco product', 'heat-not-burn', 'IQOS', and 'tobacco heating system'. The search was time-restricted to update a previous search conducted on 8 November 2021, on IQOS data from 2010-2021. The data source [independent, Philip Morris International (PMI), or other manufacturers] was retrieved from relevant sections of each publication. Publications were categorized into two general categories: 1) Toxicity assessments included in vitro, in vivo, and systems toxicology studies; and 2) The impact on human health included clinical studies assessing biomarkers of exposure and biomarkers of health effects. Generally, independent studies used classical in vitro and in vivo approaches, but PMI studies combined these with modeling of gene expression (i.e. systems toxicology). Toxicity assessment and health impact studies covered pulmonary, cardiovascular, and other systemic toxicity. PMI studies overall showed reduced toxicity and health risks of IQOS compared to cigarettes, but independent data did not always conform with this conclusion. This review highlights some discrepancies in IQOS risk assessment regarding methods, depth, and breadth of data collection, as well as conclusions based on the data source.

Heated Tobacco Products Have Detrimental Effects on Rotator Cuff Healing, Similar to Conventional Cigarettes

BACKGROUND

Cigarette smoking impairs rotator cuff healing, but no study, to our knowledge, has focused on the association between heated tobacco products and rotator cuff tears.

METHODS

This study retrospectively investigated 1,133 patients who underwent arthroscopic repair of symptomatic rotator cuff tears between March 2011 and April 2021. Patients were grouped on the basis of their smoking patterns as nonsmokers, cigarette smokers, and heated tobacco smokers. Propensity score matching was used to reduce selection bias, and 45 subjects were selected from each group via 1:1:1 matching. Functional scores and active range of motion were compared among the 3 groups preoperatively and at a 2-year follow-up. Postoperative magnetic resonance imaging was performed 6 months after the surgical procedure to assess structural integrity.

RESULTS

Except for sex, similar baseline characteristics were achieved after propensity score matching. There were no differences in the clinical scores or range of motion between the matched groups either preoperatively or at the 2-year follow-up. However, the retear rate for the matched nonsmoker group was significantly lower (8.9%) than those for the matched cigarette smoker group (31.1%) and the heated tobacco smoker group (28.9%) (p = 0.022). Multivariable logistic regression analysis revealed that the retear rates were 3.403 times higher for the cigarette smoker group and 3.397 times higher for the heated tobacco smoker group than that for the nonsmoker group.

CONCLUSIONS

Heated tobacco users, like conventional cigarette smokers, have worse clinical outcomes with respect to rotator cuff healing than nonsmokers. Regardless of the type of cigarette, abstinence from smoking is necessary for patients undergoing rotator cuff repair surgery.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Smoking and osteoimmunology: Understanding the interplay between bone metabolism and immune homeostasis

Smoking continues to pose a global threat to morbidity and mortality in populations. The detrimental impact of smoking on health and disease includes bone destruction and immune disruption in various diseases. Osteoimmunology, which explores the communication between bone metabolism and immune homeostasis, aims to reveal the interaction between the osteoimmune systems in disease development. Smoking impairs the differentiation of mesenchymal stem cells and osteoblasts in bone formation while promoting osteoclast differentiation in bone resorption. Furthermore, smoking stimulates the Th17 response to increase inflammatory and osteoclastogenic cytokines that promote the receptor activator of NF-κB ligand (RANKL) signaling in osteoclasts, thus exacerbating bone destruction in periodontitis and rheumatoid arthritis. The pro-inflammatory role of smoking is also evident in delayed bone fracture healing and osteoarthritis development. The osteoimmunological therapies are promising in treating periodontitis and rheumatoid arthritis, but further research is still required to block the smoking-induced aggravation in these diseases.

Translational potential

This review summarizes the adverse effect of smoking on mesenchymal stem cells, osteoblasts, and osteoclasts and elucidates the smoking-induced exacerbation of periodontitis, rheumatoid arthritis, bone fracture healing, and osteoarthritis from an osteoimmune perspective. We also propose the therapeutic potential of osteoimmunological therapies for bone destruction aggravated by smoking.

Emerging factors affecting peri-implant bone metabolism

Implant dentistry has evolved to the point that standard implant osseointegration is predictable. This is attributed in part to the advancements in material sciences that have led toward improvements in implant surface technology and characteristics. Nonetheless, there remain several cases where implant therapy fails (specifically at early time points), most commonly attributed to factors affecting bone metabolism. Among these patients, smokers are known to have impaired bone metabolism and thus be subject to higher risks of early implant failure and/or late complications related to the stability of the peri-implant bone and mucosal tissues. Notably, however, emerging data have unveiled other critical factors affecting osseointegration, namely, those related to the metabolism of bone tissues. The aim of this review is to shed light on the effects of implant-related factors, like implant surface or titanium particle release; surgical-related factors, like osseodensification or implanted biomaterials; various drugs, like selective serotonin reuptake inhibitors, proton pump inhibitors, anti-hypertensives, nonsteroidal anti-inflammatory medication, and statins, and host-related factors, like smoking, diet, and metabolic syndrome on bone metabolism, and aseptic peri-implant bone loss. Despite the infectious nature of peri-implant biological complications, these factors must be surveyed for the effective prevention and management of peri-implantitis.

Tobacco heating system has less impact on bone metabolism than cigarette smoke

Cigarette smoking promotes osteoclast activity, thus increasing the risk of secondary osteoporosis, leading to osteoporosis-associated fracture and impaired fracture healing. Heated tobacco products (HTP) are considered potential reduced-risk alternatives to cigarettes. However, their impact on bone metabolism remains to be elucidated. We developed an in vitro model that mimics in vivo bone cell interactions to comparatively evaluate the effects of HTPs and cigarette smoke on bone cell functionality and viability. We generated an in vitro coculture system with SCP-1 and THP-1 cells (1:8 ratio) cultured on a decellularized Saos-2 matrix with an optimized coculture medium. We found that, following acute or chronic exposure, particulate matter extract from the aerosol of an HTP, the Tobacco Heating System (THS), was less harmful to the bone coculture system than reference cigarette (1R6F) smoke extract. In the fracture healing model, cultures exposed to the THS extract maintained similar osteoclast activity and calcium deposits as control cultures. Conversely, smoke extract exposure promoted osteoclast activity, resulting in an osteoporotic environment, whose formation could be prevented by bisphosphonate coadministration. Thus, THS is potentially less harmful than cigarette smoke to bone cell differentiation and bone mineralization - both being crucial aspects during the reparative phase of fracture healing.

Searching for the Optimal Donor for Allogenic Adipose-Derived Stem Cells: A Comprehensive Review

Adipose-derived stem cells comprise several clinically beneficial qualities that have been explored in basic research and have motivated several clinical studies with promising results. After being approved in the European Union, UK, Switzerland, Israel, and Japan, allogeneic adipose-derived stem cells (darvadstrocel) have been recently granted a regenerative medicine advanced therapy (RMAT) designation by US FDA for complex perianal fistulas in adults with Crohn's disease. This huge scientific step is likely to impact the future spread of the indications of allogeneic adipose-derived stem cell applications. The current knowledge on adipose stem cell harvest describes quantitative and qualitative differences that could be influenced by different donor conditions and donor sites. In this comprehensive review, we summarize the current knowledge on the topic and propose donor profiles that could provide the optimal initial quality of this living drug, as a starting point for further applications and studies in different pathological conditions.

Optimisation of the HepaRG cell line model for drug toxicity studies using two different cultivation conditions: advantages and limitations

The HepaRG cell line represents a successful model for hepatotoxicity studies. These cells are of human origin and are differentiated in vitro into mature and functional hepatocyte-like cells. The objective of this research was to compare two different culture protocols, Sison-Young et al. 2017 (hereinafter referred as Sison) and Gripon et al. 2002 (hereinafter referred as Biopredic) for HepaRG cells in order to optimise this model for drug metabolism and toxicity testing studies. HepaRG cells obtained from the same batch were cultured according to the described protocols. Using both protocols, differentiated HepaRG cells retained their drug metabolic capacity (major phase I/II enzymes) and transporters, as well as their morphological characteristics. Morphologically, HepaRG cells cultured after the Biopredic protocol formed more apical membranes and small ductular-like structures, than those cultivated using the Sison protocol. Also, the efflux activity of multidrug resistance protein 1 (MDR1) and multidrug resistance-associated protein 1 (MRP1) as well as the activity of uridine-glucuronosyltransferase (UGT) and glutathione S-transferase (GST) were significantly reduced in HepaRG cultured using the Sison protocol. Applying well-established drug cocktails to measure cytochrome P450 (CYPs) activity, we found that production of the corresponding metabolites was hampered in Sison-cultured HepaRG cells, indicating that the activity of CYP1A2, CYP2C9, CYP3A4, CYP2B6 and CYP2C19 was significantly reduced. Moreover, HepaRG sensitivity to well-known drugs, namely diclofenac, amiodarone, imipramine and paracetamol, revealed some differences between the two culture protocols. Furthermore, the HepaRG cells can be maintained with higher viability and sufficient CYPs activity and expression (i.e. CYP3A4, CYP1A2 and CYP2B6) as well as liver-specific functions, using Biopredic compared with the Sison culture protocol. These maintained liver-specific functions might be dependent on the prolongation of the culture conditions in the case of the Biopredic protocol. In conclusion, based on the metabolic activity of HepaRG cells using the standard protocol from Biopredic, we believe that this protocol is optimal for investigating drug metabolism and pharmacokinetic screening studies.

Optimization of Mesenchymal Stromal Cell (MSC) Manufacturing Processes for a Better Therapeutic Outcome

MSCs products as well as their derived extracellular vesicles, are currently being explored as advanced biologics in cell-based therapies with high expectations for their clinical use in the next few years. In recent years, various strategies designed for improving the therapeutic potential of mesenchymal stromal cells (MSCs), including pre-conditioning for enhanced cytokine production, improved cell homing and strengthening of immunomodulatory properties, have been developed but the manufacture and handling of these cells for their use as advanced therapy medicinal products (ATMPs) remains insufficiently studied, and available data are mainly related to non-industrial processes. In the present article, we will review this topic, analyzing current information on the specific regulations, the selection of living donors as well as MSCs from different sources (bone marrow, adipose tissue, umbilical cord, etc.), in-process quality controls for ensuring cell efficiency and safety during all stages of the manual and automatic (bioreactors) manufacturing process, including cryopreservation, the use of cell banks, handling medicines, transport systems of ATMPs, among other related aspects, according to European and US legislation. Our aim is to provide a guide for a better, homogeneous manufacturing of therapeutic cellular products with special reference to MSCs.

An Overlooked Bone Metabolic Disorder: Cigarette Smoking-Induced Osteoporosis

Cigarette smoking (CS) leads to significant bone loss, which is recognized as an independent risk factor for osteoporosis. The number of smokers is continuously increasing due to the addictive nature of smoking. Therefore it is of great value to effectively prevent CS-induced osteoporosis. However, there are currently no effective interventions to specifically counteract CS-induced osteoporosis, owing to the fact that the specific mechanisms by which CS affects bone metabolism are still elusive. This review summarizes the latest research findings of important pathways between CS exposure and bone metabolism, with the aim of providing new targets and ideas for the prevention of CS-induced osteoporosis, as well as providing theoretical directions for further research in the future.

Direct Current Electrical Fields Improve Experimental Wound Healing by Activation of Cytokine Secretion and Erk1/2 Pathway Stimulation

There is growing evidence that cell behaviors can be influenced by the direct current electric fields (EFs). Some behaviors may influence wound healing directly. This study aimed to investigate the effects of EF (200 mV/mm) on immortalized nontumorigenic human epidermal (HaCaT) cells. We established a setup that can transmit an EF and maintain a stable cell culture environment. An EF was applied to HaCaT cells, and scratch-assays were performed as a model of wound healing to observe cell migration. Proliferation was evaluated by mitochondrial activity, total protein, and DNA content. Secretion of healing-associated cytokines was evaluated via cytokine arrays, and Western blot was applied to investigate signaling pathway alterations. Compared with the control group, the migration of cells exposed to EFs significantly increased (p < 0.01). After 7 days, the changes in proliferation also increased significantly (p < 0.05). The cytokine arrays revealed that granulocyte-macrophage colony-stimulating factor (GM-CSF) was the most abundant factor secreted by HaCaT following EF exposure. The signals for phospho-Erk1/2 showed a significant (p < 0.0001) increase following EF exposure. The results demonstrate that exposure of HaCaT cells to EFs has positive effects on migration, proliferation, and cytokine secretion—three important steps in wound healing—and these effects may be partially mediated by activation of the Erk1/2 signaling pathway.

Heat-not-burn tobacco (IQOS), oral fibroblasts and keratinocytes: cytotoxicity, morphological analysis, apoptosis and cellular cycle. An in vitro study

OBJECTIVES

The aim of this work is to investigate the biological effects of IQOS smoking on human gingival fibroblasts and human keratinocytes analysing cell viability, morphology, migration, apoptosis and cell cycle.

BACKGROUND

Electronic cigarettes and tobacco heating systems have been marketed to reduce smoking damages caused by combustion.

METHODS

Human gingival fibroblasts and human keratinocytes viability was determined by a colorimetric assay measuring mitochondrial dehydrogenase activity (MTT assay); after an in vitro exposure of 24 h, cell morphology was analysed with scanning electron microscope and cell migration was tested by Scratch assay, a method to mimic the migration of the cells during wound healing in vivo. Apoptosis and cell cycle were analysed with flow cytometry, and the expression of related genes (p53, Bcl2, p16 and p21) was indagated using real-time polymerase chain reaction.

RESULTS

IQOS extracts increased both cell viability (23%-41% with fibroblasts and 30%-79% with keratinocytes) and migration. No morphological alterations were observed. IQOS extracts did not induced an increase in cell death, but rose the number of S- and G2/M-phase cells. IQOS extracts also significantly increased p53 expression by fibroblasts (undiluted and 6.25% dilution, 2- and 3.6-fold higher, respectively) and reduced both Bcl2 (about two- and fivefold, respectively) and p21 expressions (about twofold with both extracts), while on keratinocytes both undiluted and 6.25% dilution extracts increased Bcl2 expression (about four- and threefold higher, respectively) and reduced p53 expression (about two- and fivefold, respectively).

CONCLUSION

IQOS smoke seemed to induce proliferation as highlighted by a viability assay, and migration and cell cycle analysis. The increased cell proliferation induced by IQOS devices must be carefully investigated for its possible clinical effects on oral cell populations.

A simple method for decellularizing a cell-derived matrix for bone cell cultivation and differentiation

The extracellular matrix regulates cell survival, proliferation, and differentiation. In vitro two-dimensional cell experiments are typically performed on a plastic plate or a substrate of a single extracellular matrix constituent such as collagen or calcium phosphate. As these approaches do not include extracellular matrix proteins or growth factors, they fail to mimic a complex cell microenvironment. The cell-derived matrix is an alternative platform for better representing the in vivo microenvironment in vitro. Standard decellularization of a cell-derived matrix is achieved by combining chemical and physical methods. In this study, we compared the decellularization efficacy of several methods: ammonium hydroxide, sodium dodecyl sulfate (SDS), or Triton X-100 with cold or heat treatment on a matrix of Saos-2 cells. We found that the protocols containing SDS were cytotoxic during recellularization. Heat treatment at 47 °C was not cytotoxic, removed cellular constituents, inactivated alkaline phosphatase activity, and maintained the levels of calcium deposition. Subsequently, we investigated the differentiation efficiency of a direct bone coculture system in the established decellularized Saos-2 matrix, an inorganic matrix of calcium phosphate, and a plastic plate as a control. We found that the decellularized Saos-2 cell matrix obtained by heat treatment at 47 °C enhanced osteoclast differentiation and matrix mineralization better than the inorganic matrix and the control. This simple and low-cost method allows us to create a Saos-2 decellularized matrix that can be used as an in vivo-like support for the growth and differentiation of bone cells.

Cigarette smoke-associated inflammation impairs bone remodeling through NFκB activation

Background

Cigarette smoking constitutes a major lifestyle risk factor for osteoporosis and hip fracture. It is reported to impair the outcome of many clinical procedures, such as wound infection treatment and fracture healing. Importantly, although several studies have already demonstrated the negative correlation between cigarette consume and impaired bone homeostasis, there is still a poor understanding of how does smoking affect bone health, due to the lack of an adequately designed animal model. Our goal was to determine that cigarette smoke exposure impairs the dynamic bone remodeling process through induction of bone resorption and inhibition of bone formation.

Methods

We developed cigarette smoke exposure protocols exposing mice to environmental smoking for 10 days or 3 months to determine acute and chronic smoke exposure effects. We used these models, to demonstrate the effect of smoking exposure on the cellular and molecular changes of bone remodeling and correlate these early alterations with subsequent bone structure changes measured by microCT and pQCT. We examined the bone phenotype alterations in vivo and ex vivo in the acute and chronic smoke exposure mice by measuring bone mineral density and bone histomorphometry. Further, we measured osteoclast and osteoblast differentiation gene expression levels in each group. The function changes of osteoclast or osteoblast were evaluated.

Results

Smoke exposure caused a significant imbalance between bone resorption and bone formation. A 10-day exposure to cigarette smoke sufficiently and effectively induced osteoclast activity, leading to the inhibition of osteoblast differentiation, although it did not immediately alter bone structure as demonstrated in mice exposed to smoke for 3 months. Cigarette smoke exposure also induced DNA-binding activity of nuclear factor kappaB (NFκB) in osteoclasts, which subsequently gave rise to changes in bone remodeling-related gene expression.

Conclusions

Our findings suggest that smoke exposure induces RANKL activation-mediated by NFκB, which could be a “smoke sensor” for bone remodeling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02836-z.