Mesenchymal stem cells (MSC) comprise a heterogeneous population of rapidly proliferating cells that can be isolated from adult  as well as fetal  tissues (termed bone marrow (BM)-, adipose tissue (AT)-, and umbilical cord (UC)-MSC, respectively) and are capable of differentiation into a wide range of non-hematopoietic cell types. An additional, unique attribute of MSC is their ability to home to tumor sites and to interact with the local supportive microenvironment which rapidly conceptualized into MSC-based experimental cancer cytotherapy at the turn of the century. Towards this purpose, both naïve (unmodified) and genetically modified MSC  have been employed using well-established in vitro and in vivo cancer models, albeit with variable success. The first approach is hampered by contradictory findings regarding the effects of naïve MSC of different origins on tumor growth and metastasis, largely attributed to inherent biological heterogeneity of MSC as well as experimental discrepancies. In the second case, although the anti-cancer effect of GM-MSC is markedly improved over that of naïve cells, it is yet apparent that some protocols are more efficient against some types of cancer than others. Regardless, in order to maximize therapeutic consistency and efficacy, a deeper understanding of the complex interaction between MSC and the tumor microenvironment is required, as well as examination of the role of key experimental parameters in shaping the final cytotherapy outcome. This systematic review represents, to the best of our knowledge, the first thorough evaluation of the impact of experimental anti-cancer therapies based on MSC of human origin . Importantly, we dissect the commonalities and differences as well as address the shortcomings of work accumulated over the last two decades and discuss how this information can serve as a guide map for optimal experimental design implementation ultimately aiding the effective transition into clinical trials.The online version of this article (10.1186/s13287-018-1078-8) contains supplementary material, which is available to authorized users. In the turn of the millennium after over four decades of intensive research in the genetics of cancer, an important paradigm shift has occurred, in which instrumental for the development of the disease is not only the link between cumulative instability of key genes and the rise of aberrant cell cycle control, but also the orchestration of a heterogeneous cell-based stromal network supportive of tumor invasion and metastasis. This switch in focus has led to the elucidation of the composition of this microenvironmental niche and of the interaction dynamics of its multiple cellular and extracellular components. Concomitant have been the emergence of the epithelial-to-mesenchymal transition (EMT) process as a key cellular mechanism in tumorigenesis, as well as the important discovery that stem cells of mesenchymal origin ) can home towards tumor sites. The latter has formed the basis of an exciting new anti-cancer strategy, namely cancer cytotherapy, in which allogeneic MSC can be used to specifically target and deregulate the local tumor microenvironment, as an answer to modern oncology’s desperate need for a promising alternative to the current gold-standard therapy of combined chemotherapy , as well as by multi-parameter variability relating to the methods, processes and manipulation steps mediating transformation of lab findings to clinical-grade products.With a mortality rate of nearly 60% for the over 14 million people diagnosed with cancer yearly worldwide, it is imperative that any novel therapeutic regime should be optimized to its full potential. Obviously, experimental cancer cytotherapy is at a nodal point, where the critical mass of information accumulated by the series of studies performed over the last two decades needs to be thoroughly revised, carefully analyzed, and properly evaluated in the context of immunobiology of the tumor microenvironment. With the first-in-human clinical trials assessing genetically modified MSC in gastrointestinal and lung cancer settings only very recently and more to follow, this task has become an essential one more than ever before [With all the above in mind, we present here a systematic review of the advances in the MSC-based cancer cytotherapy field from its inception onwards, including the state-of-the art of the biology and relationship between the effectors (MSC populations) and targets (tumor niche components) implicated , infiltrating inflammatory and immune cells, extracellular matrix (ECM), (myo) fibroblastic cells ), mesenchymal stromal/stem cells, and sometimes adipocytes , as wellAmong the immune cells that infiltrate the tumor stroma and are present within the tumor microenvironment, selective T and B lymphocyte populations favor or suppress tumor growth and their detection has been associated with subsequent clinical outcomes –7. TumorPerivascular stromal cells, known as pericytes, are another essential component of the tumor stroma that secures vasculature maintenance by providing structural support to blood vessels . AlthougFibroblastic stromal cells within the tumor stroma, known as TAFs, have been linked to several processes that promote cancer metastasis and growth, including angiogenesis , EMT 1313, and pECM is another key regulator of tumor development and progression by providing both a structural scaffold for the tumor stroma and also active soluble factors including growth and angiogenic factors, cytokines, and chemokines that regulate tumor behavior. During tumor development, the ECM is usually disorganized and collagen deposition as well as cross-linking with other matrix proteins such as elastins, laminins, or fibronectin has been associated with cancer invasion and metastasis . Among tΕΜΤ is the process by which epithelial cells reduce the expression or function of proteins that promote cell-cell and cell-basement-membrane adhesion and thus obtain a mesenchymal-like phenotype. Except for the regulation of metastatic properties, the EMT has been also associated with acquired drug resistance . FurtherStem cells possess a unique capacity of self-renewal, differentiation into multiple cell types and in vivo tissue repopulation . These fAnother common feature of MSC is that they are able to localize to sites of hematopoiesis, inflammation, or injury as well as to solid tumors, by a mechanism characterized as homing. Tumor tropism distinguishes MSC from other mesenchymal cells, such as differentiated fibroblasts . This hoTumor tropism of MSC and the dynamic interaction between MSC and the tumor microenvironment, due to their complexity as well as their significance for cancer therapy, require a deeper understanding and merit further investigation and hence are discussed in more detail in the following sections of this review.Homing is the process by which cells migrate to, and engraft in, the tissue in which they can exert local functional effects. It is well established that MSC are recruited to sites of injury to support tissue repair, stem cell homeostasis, and immunomodulation. Tumors can be considered as chronic wounds and, thus, attract MSC in similar ways as injured tissues . The homIt is believed that the mechanisms orchestrating MSC homing to sites of injury, and consequently to tumors, resemble the migration of leukocytes towards sites of injury and inflammation, which is well studied. It has been demonstrated that bone marrow stroma-derived MSC (BM-MSC) express high levels of adhesion molecules, including integrins β1 and a4, which can mediate the engraftment of MSC to the bone marrow , 45. TheOnce in the tumor, attracted MSC interact with the tumor microenvironment leading to its remodeling and promoting cancer progression. It has been reported that MSC that home to tumor sites are transformed into TAFs  and promAnother way of communication between MSC and cancer cells includes the exchange of microparticles, like exosomes. MSC-derived exosomes can modulate the function of tumor cells through induction of MMP-2 and ecto-5′-nucleotidase activity, thus enhancing the heterogeneity within the tumor microenvironment , while tThe tumor microenvironment is a highly dynamic, plastic, and heterogeneous welter of cells and cellular factors that provide support and protection to the developing tumor and thus its therapeutic targeting constitutes a popular anti-cancer approach , 53. TheThe unique homing property of MSC has been exploited in cancer cytotherapy protocols using various MSC populations (mainly of adult origin), either naïve or engineered to carry genes with antitumorigenic properties. But whilst genetically modified adult MSC have shown good efficacy in ex vivo and animal cancer models, naïve cells, on the contrary, have produced largely conflicting results by either promoting or suppressing tumor development. For a long period of time, mainly between 2000 and 2006, the research involving MSC-based cancer cytotherapy was limited only in the use of BM-MSC, with, in most cases, lack of encouraging results –58. On tBesides conflicting results observed within specific MSC (effector) and tumor (target) combinations, contradictory findings have also been obtained with regard to the effect of different MSC populations on the same tumor target, strongly suggesting a close association between the antitumorigenic properties of the former and their developmental origin. With respect to breast cancer, for example, a great number of studies (mainly in vitro) have quite convincingly showed a robust tumor-promoting effect of both BM-MSC , 74–78 aFinally, apart from the cases where the dubious efficacy of certain MSC against some tumors arises from contrasting reports in the literature, there are also cases where questions are raised over the therapeutic value of those naïve MSC that have been shown to possess strong onco-suppressive characteristics, albeit by yet unconfirmed reports. Such examples are the cases of AT-MSC vs. pancreatic cancer , BM-MSC Clearly, more focused work will lead to data accumulation, analysis of which will help in identifying trends and will fill in knowledge gaps regarding effectiveness of experimental cancer cytotherapy, at the same time shedding more light on the underlying biological mechanisms.In the following sections, we discuss some of these mechanisms that may attribute to the complexity and adversity of experimental cancer cytotherapy outcomes and next present our meta-analysis strategy for decoding all available data from the field at its current state of maturity.Once MSC migrate to the sites of tumor development, they interact with components of the neoplastic parenchyma as well as with supportive stroma. The exact dynamics of this crosstalk is dependent on the developmental stage and origin of the MSC as well as the type and site of tumor targeted. Nevertheless, the final outcome, tumor support or suppression, is most likely determined by the resulting tilt in balance between the respective mediating mechanisms (reviewed in ). In theΑ significant amount of in vivo experimental data, including labeled MSC tracking, support the contribution of MSC to the tumor vascular and fibrovascular network, either directly by differentiating into pericytes, fibroblasts, and myofibrobasts that transform into TAFs , 85 or iOnce in the tumor microenvironment, MSC acquire expression of TAF antigens, such as a-smooth muscle actin (a-SMA), fibroblast-specific protein, vimentin, and SDF-1 in vivo and in vitro following co-culture with tumor cells or using tumor-conditioned media , 89. In MSC also secrete various pro-angiogenic factors, such as VEGF, fibroblast-derived growth factor, PDGF, and stromal-derived factor-1 (SDF-1), that facilitate angiogenesis through promotion of endothelial and smooth muscle migration and proliferation towards the tumor site . MSC-expOn the other hand, a number of studies support the involvement of MSC in suppression of the tumor angiogenic network. MSC were found to migrate towards and inhibit growth of endothelial cell-derived capillaries in vitro through production of reactive oxygen species. The growth-suppressing effect of MSC was also observed in vivo, where established melanoma tumors injected with MSC exhibited lower vascular density .MSC are thought to promote tumorigenesis through their immunomodulatory behavior, which is characterized mainly by immunosuppressive effects that can be beneficial for cancer cells to escape the immune system surveillance . MSC actThe in vivo immunomodulatory effects of MSC are still poorly studied within tumors. In a study by Djouad et al., the reported immunosuppressive action of MSC led to a higher incidence of melanoma formation in an allogeneic mouse model . Based oThe contribution of MSC to the establishment of distant metastases is rather controversial, ranging from promotion to suppression in a number of studies. For example, intravenous injection of MSCs derived from umbilical cord blood or adipose tissue reduced the formation of lung metastases in mice with established mammary tumors . In contMSC may also modulate EMT, a developmental process that is subverted by tumor cells, resulting in a more invasive phenotype. Co-culture of breast cancer cells with MSC resulted in upregulation of EMT-specific markers  and a decrease in E-cadherin . AnotherIn many cases, the tumoricidal action of MSC on tumors has been associated with suppressive effects on signaling pathways crucial for cancer progression, proliferation, and survival, mainly involving the PI3K/AKT and Wnt pathways. Inhibition of AKT was reported in a Kaposi’s sarcoma model, where intravenously injected MSC migrated to tumors and effectively inhibited tumor proliferation . MSC canMany studies have concentrated on the anti-cancer functions of neonatal MSC, highlighting the primitive characteristics that render them non-tumorigenic. Among these, WJ-MSC show modest expression of pluripotency genes and high levels of several tumor suppressor genes, while they secrete a variety of growth factors and cytokines that inhibit tumor growth , 117.Studies investigating the effects of MSC on tumors have shown that they either promote or inhibit apoptosis, leading to tumor attenuation or progression, respectively. Interactions between MSC and cancer cells in the bone marrow have been shown to promote survival of acute myelogenous leukemia through upregulation of anti-apoptotic bcl-2 with reduced rates of apoptosis in response to cytotoxic chemotherapy . FurtherOn the other hand, Lu et al. demonstrated that MSC had an inhibitory effect on mouse tumor cells and ascitogenic hepatoma cells in a cell-dependent manner involving Caspase 3, an apoptotic protein, and p21, a negative regulator of cell cycle, implying that MSC exert tumor inhibitory effects in the absence of host immunosuppression, by inducing G0/G1 phase arrest and apoptosis of cancer cells . G1 phasUnquestionably over the last quarter of the century, the explosion of research in molecular cell biology and immunobiology of stem cells and cancer have shed light on the composition and establishment of the tumor microenvironment, on mechanisms governing MSC homing to tumor sites and interaction with components therein, as well as on signaling cascades and molecular events mediating the pro- or antitumorigenic effects. In its majority, this bulk of knowledge has stemmed from applied work using MSC in variety of in vitro/in vivo tumor models. However, the complexity of the field and the heterogeneity and diversity of the outcomes have inevitably led to new elementary questions that remain to be resolved. Some of these are: Have research work efforts so far been correctly prioritized or have they been prone to partiality and duplication? What are the crucial areas that we may need to focus on both experimentally and conceptually in order to maximize clinical relevance/impact? To what extent is the discrepancy in results attributed to technical rather than biological heterogeneity? What are the mechanisms mediating anti-cancer efficacy in different MSC populations? Can we improve consistency and efficiency of primary outcome by optimization of experimental parameters? Is there an MSC type/source bearing “universally” consistent tumor suppressive action against a wider range of tumor targets and with fewer adverse effects in comparison to others? If so, what are the properties that give it an advantage, are they uniquely inherent, or can they be mimicked by specific experimental interventions/adaptations? Are there some MSC/tumor combinations which decisively give better results than others in experimental research work and should therefore be given priority in clinical trials? To what extent does genetic modification of MSC ameliorate the anti-cancer behavior of naïve MSC? Are specific genetic modification methodologies applied on MSC effector cells more efficient than others against tumor targets? Given the uncertainty of naïve MSC-based tumor cytotherapy and on the other hand the more robust performance of genetically modified MSC, should bench research and clinical trials focus primarily on the latter?In the following sections of this review, we present a strategy for identifying the sources of heterogeneity, for evaluating their relative impact on cytotherapy outcome, and we summarize trends and patterns ultimately using our findings to address the aforementioned issues.Until this day, several reviews have focused on summarizing the aforementioned conflicting results involving the efficacy of MSC in cancer treatment and have, in some cases and to a limited extent, tried to dissect the causal relationship to those discrepancies , 121. Thn = 55) and (b) relevant to experimental cytotherapy models utilizing genetically modified human MSC . Subsequently, detailed information available in the methodology and results sections of the manuscripts were extracted and recorded in spreadsheets using Microsoft Excel. Strings of information were classified into five broad categories, namely type of stem cells used (effectors) and type of their tumor target (tissue/ cell lines), characteristics of effector-target interface , methodology applied for cell modification/labeling and endpoint analyses/assays, and key findings and primary outcome , thus populating a preliminary descriptive database. In the following step, this compartmentalized information was further fragmented and reassigned into over 20 categories (fields) designated “experimental parameters” , belonging to the first category of articles above, (2) experiments of the second article category which refer to the use of naïve MSC as controls for evaluating GM-MSC anti-cancer efficacy (n = 43), (3) experiments (again included in the second article category) that describe the anti-cancer efficacy of GM-MSC without a direct comparison with naïve MSC (n = 24). The primary outcomes of these experiments were flagged as tumor promotion or suppression  depending on the results of the in vitro/in vivo assays as described in the respective publications. In the final step, the experimental parameters were used to derive database queries and to perform statistical analyses, the outcome of which is discussed in the following section.As part of this effort to elucidate the conditions and factors that could possibly affect the behavior of MSC against tumors, we conducted a small-scale meta-analysis based on information extracted from the literature using a four-step strategy: (1) compilation of a relevant publication library, 2) deconstruction of literature methodology and reported findings, 3) classification and organization of extracted experimental data, and (4) data consolidation and statistical analysis , which have failed to produce patient-beneficial results, as it is discussed below.Following on from addressing the frequency, distribution and clinical relevance of cancers targeted in naïve MSC-based cancer cytotherapy, we set on to evaluate the anti-cancer behavior and efficiencies of the three MSC types relative to each other. Our meta-analysis showed a differential pattern of anti-carcinogenic behavior, with BM-MSC generally being pro-tumorigenic, and UC-MSC having a more clear onco-suppressive character Fig. c. More sSwitching the focus to the specific types of tumors with markedly affected progression—either positively or negatively—by MSC administration, our meta-analysis revealed the following associations Fig. . First, Obviously, the origin of the MSC population used for administration in animal tumor models plays an instrumental role in determining the fate of the treatment. Our analysis has shown that, in terms of anti-cancer efficacy, naïve BM-MSC despite the plethora of studies referring to their use in cytotherapy protocols, perform rather inefficiently. This is supported by the fact that they present the worst in vitro anti-cancer performance as discussed further on, they are frequently associated with tumor promotion both in vivo and in vitro Fig. , and theAs discussed earlier, one of our main hypotheses was that the experimental conditions could be determining factors for the pro- or antitumorigenic behavior of MSC. Thus, technical variation can supplement biological heterogeneity as a co-founding factor for the discrepancies observed in tumor modulation by naïve MSC in cancer cytotherapy protocols. The propensity of MSC to either support or suppress tumor growth is the outcome of the combination of multiple parameters, such as donor-to-donor (epi-) genetic variability, heterogeneity in the isolation of the original MSC population, heterogeneity due to in vitro cell propagation, differences in the characteristics of the in vivo tumor model adopted, divergence in the choice of cell dosing (MSC: cancer cell infusion ratios), and timing of administration (co-infusion vs. MSC administration at early or advanced stage pre-established tumors).Consequently, the classification of data extracted from studies in the literature as experimental parameters in our database was integral to our meta-analysis methodology approach. The parameters examined included choice of cell culture format/ animal model, cancer cell lines, in vivo cell administration scheme (route and timing), and MSC to cancer cell ratio. This was done in order to investigate the influence of each parameter alone or in combination in shaping cytotherapy outcomes and contributing to heterogeneity Fig.  and 3.TaAlthough we are anything but close to identifying the unequivocally ideal conditions under which MSC will be able to diminish tumor growth, findings that stemmed from analyses of core parameters in our study combined with the state-of-the-art knowledge could help build some generalizations regarding optimal conditions; these are discussed in the following lines and summarized in Table xenograft models included in our analyses provide excellent representation of human disease allowing the engraftment, growth, and interaction of human MSC and human cancer cells, the majority (two thirds) of the studies were conducted on athymic mice. The latter bear the advantage of being less immunodeficient than SCID variants, therefore more convincingly recapitulate immune system- affiliated antitumor therapeutic responses and disease progression [With regard to the experimental model adopted, our analysis showed that the animal model employed in in vivo cytotherapy protocols, and, in parallel, the cultivation conditions (culture format) of effector and target cells in vitro, could be decisive factors for the fate of MSC-based treatments Fig. . At thisgression . As showgression –99. Moregression . Furthergression . From thIn vitro cancer cytotherapy experimental models comprise two main types: (a) co-cultures of MSC and cancer cells, where cells communicate (two-way interaction) either directly through physical contact and the formation of gap junctions, or indirectly via exchange of soluble factors , and (b) monocultures of target (tumor) cells, which are grown in and react to culture media in which the effector cells (MSC) have been grown for 24–48 h (conditioned media (CM)). This second culture model basically allows only unilateral signal communication (from the effector to the target/responder cell). In both experimental settings, BM-MSC had mainly pro-tumorigenic effects on cancer cells, while on the contrary, UC-MSC were mostly antitumorigenic . Nevertheless, it is interesting that only 12% of the studies used two or more representative cell lines to describe and confirm the observed effects on the tumor tested. In an effort to test whether MSC exhibit distinct behavioral imprints on different cell lines of the same cancer tissue, we focused on breast cancers, since not only they were the most popular tumor target, but also the one represented by a large number of cell lines, as stated above. We compared data from two of the most commonly used cell lines, MDA-MB-231 and MCF-7, vs. all eight available breast cancer cell lines  as one of the key factors influencing cancer cytotherapy outcome. Cross-examination of the data in Tables Our analysis has also highlighted the cell dosing, MSC-to-cancer cells ratios lower than one (< 1)  seem overall to be better associated with tumor inhibition in vivo (45.8% vs. 30% for ratios > = 1) (Table In terms of 1) Table . Interes1) Table  and 3. Iconsensus of experimental parameters affiliated to either tumor suppression or promotion by recording the frequently observed (> 50% frequency) value in each case. Although the data did not allow a consensus to be built in the first case, a set of parameters were identified that could be regarded, either alone or in combination, as “tumor promotion-statistically associated experimental parameters” in preclinical cytotherapy studies. Such factors are listed in Table As a final step in our analysis, we attempted to derive a The process of in vitro/ex vivo MSC expansion is necessary in order to obtain clinically significant cell numbers. This procedure is nevertheless time-consuming, costly, and poses cell contamination and loss risks, thus ideally the MSC source should allow the relatively easy, high-yield isolation of populations with propagation characteristics that minimize sub-cultivation time.A large number of studies have unequivocally demonstrated that variations in ex vivo manipulation conditions, such as age and anatomical origin of donor tissue , 135 harThe contribution of MSC expansion on the discrepancies observed regarding their antitumor behavior can only be speculated, since astonishingly, no preclinical cancer cytotherapy study so far has focused on evaluating the effect of variations in sub-cultivation characteristics of a given MSC type on specific cancer types. This would be particularly interesting as it would not only pinpoint the impact of this source of variation on cytotherapy efficacy but also on adequacy and would aid towards the establishment of some rudimentary good manufacturing practice (GMP) standards in light of the clinical trials .With regard to the differences in ex vivo expansion between various MSC types, a significant amount of studies show that they are ontogeny-related, with many underlining the superiority of MSC isolated from fetal umbilical cord tissue, over those derived from adult tissues (bone marrow and adipose tissue) –145. Mor17 UC-MSC (40 PD) over a 2-month culture period have been reported (in sharp contrast to only 5 × 107 (8PD) for BM-MSC) [2 environment (5%) [With respect to ex vivo growth kinetics, UC-MSC bear three distinct advantages over adult MSC. First, the isolation procedure results in larger pool of adherent, clonogenic cells (MSC), especially compared to BM-derived MSC. There are various studies reporting a yield of 10,000–15,000 MSC per cm of umbilical cord tissue in the starting culture , 154, wh BM-MSC) . Interesent (5%) , 172 or ent (5%) , 174 furent (5%) . On the ent (5%) , 168. A ent (5%) , 176. Inent (5%) , 178.With regard to the role of MSC expansion in cancer cytotherapy in specific, we could not draw any conclusions, since no detailed information/experimental data were available  regarding status of cells utilized . However, taking into consideration the growth kinetics and bearing in mind that the optimal MSC: cancer cell ratio should be 1:1 to 1:2 Table , one couIn the introductory section, we gave a brief account of the characteristics that MSC share and form the basis of their adoption as valuable cytotherapy tools. Nevertheless, our literature meta-analysis has revealed that with respect to anti-cancer efficacy it is their differences in genotypic and phenotypic attributes that are more important. This notion is based on the observation that the most prominent disparity in the outcome of cancer cytotherapy is MSC (effector)-related. Some naïve MSC populations are more effective against specific tumor targets, where others underperform and may even prove deleterious for cancer treatment. A prime example of the latter case is the pro-tumorigenic effect of BM-MSC and AT-MSC on metastatic breast cancer. On the contrary, UC-MSC show an anti-carcinogenic response that is both strong and robust, i.e., less sensitive to experimental conditions such as choice of ex vivo model and cell dosing. According to our findings, based on the data available so far, fetal-derived UC-MSC are safer to use and more frequently associated with suppression of tumor growth than MSC derived from human adult tissues. This is backed up by comparative studies evaluating the anti-cancer effects of MSC of different developmental origin , 129, alpluripotency and self-renewal markers such as Oct-4, NANOG, LIF, SSEA-1, SSEA-4, Tra-1–60, and Tra-1–81 [spontaneous transformation [There is sufficient evidence in the literature suggesting that the unique combination of the biological traits suited for giving UC-MSC their special role in human development actually allows them to serve a second purpose as naturally anti-cancer capable cytotherapy agents. UC-MSC are primitive cells falling in the developmental map between hESC and adult stem cells . They shTra-1–81 , 183. InTra-1–81 , 154. Moormation , 185. Inormation , 187. Thormation . Furtherormation , 89, 189ormation , 191. Neormation . Apparenormation . Similarormation . Last, aormation . Althougsecretome scores very low in terms of tumor suppression . MSC-derived EV (MSC-EV), which mainly comprise the nano-scale, endosome-derived exosomes, and the larger microvesicles, are considered as potent regulators of intercellular communication. The main biological potency of MSC-EV is maintenance of tissue homeostasis and mainly involves targeting housekeeping biochemical activities; however, they are also believed to play an important role in the dissemination of cancer phenotype. Data so far suggest that MSC-EV are an integral part of autocrine and paracrine signaling events modulating expansion of the tumor microenvironment, angiogenesis, and metastasis. Little is known about the exact mechanisms but data so far are indicative of complex regulation involving antagonistic effects [Lately, it has become evident that MSC secretome-mediated effects on cancer cells implicate the delivery of bio-molecular cargo  packaged into membrane structures called  effects , 204. Th effects , but eve effects , 206.With respect to the immune system-affiliated antitumor effect of MSC, our meta-analysis did not allow us to make any clear deductions regarding the differences between fetal and adult MSC, since for the reasons explained earlier we chose to exclude data derived from syngeneic models which have proper antitumor responses ) and better represent the contribution of the host microenvironment to the triadic interaction of MSC: cancer cells: stromal supportive cells. Nevertheless, the immunomodulatory properties of fetal and adult MSC have been quite well documented in comparison , 208; moimmunomodulation are believed to be directly linked to the duality of results in experimental cytotherapy of cancer. For example, polarization of BM-MSC (through specific priming of Toll-like receptors (TLR)) into proinflammatory or immunosuppressive phenotype directly correlates to tumor suppressive or tumor-promoting effects, respectively [Differences in ectively , 212. Thectively . With reectively . Primingectively . Last, wectively .The differences in immunomodulatory function between adult MSC and UC-MSC are not restricted to adaptive immune responses. Raicevic and colleagues have demonstrated a lower reactivity to bacterial or viral infections involving innate immunity mechanisms. In MLR containing CD3+ T cells, UC-MSC resist the neutralizing effect of inflammation or TLR ligation on their immunosuppressive properties by lacking TLR4 expression and by overproduction of HGF  .low immunogenicity, which is a key requirement for allogeneic transplantation. UC-MSC/WJ-MSC, like their adult counterparts, evade immune recognition by lacking co-stimulatory molecule expression  which are normally implicated in activation of both T and B cell responses. However, crucially, UC-MSC distinguish themselves from adult MSC with respect to expression of major histocompatibility complex (MHC) molecules. UC-MSC express significantly lower levels of MHC class I (HLA-ABC) both at rest and following stimulation with IFN-γ, while MHC class II (HLA-DR) induction with IFN-γ treatment is substantially augmented in BM-MSC but is very negligible in WJ-MSC [Recently, the unique immunomodulatory properties of UC-MSC have been linked to secreted components of their ECM. In a study involving a mouse corneal transplantation model, Coulson-Thomas and colleagues showed that UC-MSC actively suppress inflammatory immune response of the host microenvironment by favoring M2 macrophage phenotype (anti-inflammatory) over M1 (proinflammatory) and by inducing maturation of T-regs and inflammatory cell death. They do this by secreting components of their unique glycocalyx which constitutes the characteristic matrix in which the cells naturally reside and function . One of n WJ-MSC , 218. Thn WJ-MSC . BM-MSC n WJ-MSC . The expn WJ-MSC . Interesn WJ-MSC .Human UC-MSC have been also found to differ from adult MSC with respect to the expression of HLA-G, a non-classical HLA class I molecule which plays a key role in maternal tolerance for the developing fetus . UC-MSC,Despite their immunosuppressive properties and low immunogenicity, under certain circumstances, UC-MSC can elicit an immune response which should be taken into consideration when establishing a cytotherapy protocol . In a clinically relevant miniature swine model, while a single injection of MHC-mismatched inactivated UC-MSC did not elicit a detectable immune response, repeated injections in the same region caused the opposite effect, as evidenced by the production of alloantibodies within 1 week . TherefoOverall, ontogeny-related differences in the pattern of expression of HLA molecules , as well as in the cytokine secretion profile  between adult MSC and UC-MSC are largely responsible for the course of direct or indirect interaction with cellular components and bioactive factors of the tumor microenvironment driving the adoption of a tolerogenic/immunosuppressive or a more immunoreactive/proinflammatory phenotype, which ultimately determines the impact on tumor progression. With this in mind, the optimal dose, frequency, and timing of MSC administration need to be carefully considered for each cancer target.Tumor specificity is the major obstacle hampering the effectiveness of current cancer treatment therapies, such as combination chemotherapy. Advanced drug targeting of tumor cells is particularly hard when treating highly invasive and/or metastatic tumors such as glioblastoma or pulmonary cancer. Uncontrolled drug distribution in the patient’s body, i.e., insufficient concentration at the tumor site and toxic concentration in normal cells, which is attributed to inefficacy of anti-cancer therapy, is often the direct cause not only of severe side effects but also, ironically, of life-threatening complications. MSC tropism towards primary and metastatic tumor locations, which occurs independent of tumor type, MSC immunocompetence and route of delivery, combined with their relatively ease of in vitro manipulation to express molecules with anti-cancer action, naturally provides a solution to drug specificity, bypassing the main issues of stability , dosing , and off-target toxicity (side effects) associated with their systemic administration. Historically, the therapeutic value of this unique “Trojan horse/smart bomb” approach for the controlled release of potent antitumorigenic agents in situ has been rather convincingly demonstrated in a large number of studies with genetically modified MSC (GM-MSC) targeting an extensive range of cancers in various experimental animal models [reviewed recently by , 225.In this review, we have concentrated on studies referring to human tumor cells specifically targeted by human GM-MSC of adult bone marrow, adipose tissue, and fetal umbilical cord matrix tissue origin, herein termed GM-BM-MSC, GM-AT-MSC, and GM-UC-MSC, respectively -target (tumor) components, the choice of transgene (anti-cancer agent) that is incorporated into the MSC carrier, as well as the enabling genetic modification technology, complete the list of methodological components. The two main strategies adopted are (a) the rather straightforward overexpression of molecules with known antitumorigenic action or (b) gene-directed enzyme/prodrug treatment (GDEPT) Table . In the (TRAIL) is a type II transmembrane protein of the tumor necrosis factor (TNF) family of ligands that is expressed by a variety of immune cells and is capable of initiating apoptosis through engagement of its receptors which are differentially expressed in normal and cancer cells [Tumor necrosis factor-related apoptosis-inducing ligand er cells . The atter cells . And siner cells . Again, er cells , glioma/er cells , 235, luer cells , 253, lier cells , 252, coer cells , and cerer cells  cancers.er cells , 234 ander cells ). Set toer cells .GDEPT , GM-MSC act as carriers of genes encoding for specific enzymes that convert non-toxic prodrugs into active derivatives [HSV-tk)/ganciclovir (GSV) and Escherichia coli cytosine deaminase (CD)/5-fluorocytosine (5-FC), with suicide genes introduced into the stem cell carriers via viral vectors (most often retroviruses)  due to indirect effects caused by their neighboring transfected cells (MSC), causing more widespread cell death than if transfected cells alone were killed [In the second strategy, ivatives . The pros) Table . One obve killed , 265. A e killed , 267, ene killed , or parae killed , 270.E. coli, the CD gene can be used for the activation of 5-FC, although the bifunctional fusion protein cytosine deaminase to uracil phosphoribosyltransferase (CD::UPRT) is preferred due to the higher bystander effect achieved in vitro and in vivo. CD::UPRT chimeric protein not only exhibits an enzymatic activity 10-fold greater than that of wild type CD and increases sensitivity to 5-FC by at least 100-fold, but also alleviates cytotoxicity resistance exhibited by some tumors [The two main GDEPT systems differ to the mechanism by which they accomplish bystander effects and consequently diverge in terms of their tumor growth suppression efficiency. In the case of CD/5-FC system, activated (deaminated) 5-FU rapidly crosses the plasma membrane by passive diffusion and exerts its cytotoxic effects by interfering with both DNA and RNA synthesis. In contrast, the active phosphorylated form of GCV is a charged metabolite unable to readily diffuse out of the cell and thus relies on physical contact and gap junctional intercellular communication (GJIC) between therapeutic and tumor cell to exert its cytotoxic action by interfering with DNA polymerase function. In the case of CD/5-FC system, yeast or e tumors , 272.Various studies have attempted to compare the efficacy of CD::UPRT/5-FC and HSVtk-MSC/GCV systems (in the absence or presence of MSC carriers). Whereas in the first case, CD::UPRT/5-FC proves superior due to its greater bystander effect, the effect on tumors targeted by CD::UPRT-MSC/5-FC or HSVtk-MSC/GCV differs depending on the expression status of enzymes of nucleotide metabolism and ATP-binding cassette (ABC) transporters, irrespective of GJIC status , 274. ThTK/GCV and CD/5-FC GDEPT comprise the minority of GM-MSC-based strategies, almost exclusively using adult MSC as cellular vehicles (with AT-MSC used in three out of four cases). Cancer types targeted include melanomas , sarcomacombination of strategies is employed as evidenced for example in the case of UC-MSC-IFN-β plus 5-FU (cytokine-transduced MSC + chemotherapy drug) for the treatment of breast cancer [It is worth highlighting that in some cases, in an effort to maximize tumor suppression efficiency, a t cancer , UC-MSC-t cancer , BM-MSC t cancer , and HSVt cancer  or breast cancer . These at cancer .Obviously, the multitude of combinations of antitumorigenic molecular cargo, cellular vehicle, tumor model, gene incorporation, and expression technology and method of administration enables the generation of a large number of individual GM-MSC-based anti-cancer strategies laying the basis for personalized cancer cytotherapy. Interestingly, a comparison of the different strategies applied in relation to a specific cancer model frequently used in experimental cytotherapy studies reveals substantial accordance in the results obtained. For example, with respect to the popular xenograft lung metastasis model, administration of human GM-MSC in mice suppressed the metastases of human MBA-MB-231 breast cells to the lung  by 62%, 81%, and 73% 72 ± 9.5%) for BM-MSC-IFN-β , BM-MSC- ± 9.5% fgene delivery system. So far all GM efforts have relied on the heavy use of viral vectors . Generally, viral vectors are more efficient at transferring genes than non-viral vectors; however, clinical studies have revealed that the efficacy of virus-mediated suicide gene therapy was limited due to adverse effects, such as toxicity, oncogenicity, and the possibility of invoking an excessive antiviral host immune response [Regardless of the strategy followed, successfully marrying high efficacy with safety is the primary challenge in developing a response . For exaresponse , 284. LVresponse . Accordiresponse . Lately,response , 288.As mentioned earlier, GM-MSC-based cancer cytotherapy has shown greater consistency in successfully suppressing tumorigenesis. Nevertheless, the difference in tumor suppression efficiency in comparison to n-MSC has been largely discussed on a qualitative, rather than a quantitative basis. Our meta-analysis approach gives for the first time, to the best of our knowledge, a quantitative dimension to the advantage of GM-MSC over n-MSC-based cancer cytotherapy. With respect to the studies using GM-MSC, they all report attenuation of tumor growth, irrespective of the type of MSC effector, tumor target, GM strategy, or animal/culture model applied. On the contrary, as previously discussed, the frequency of n-MSC studies showing a significant onco-suppressive effect varies greatly  depending on the type of MSC employed Fig. c. In othTaking all the above into consideration, it can be deduced that GM-MSC exhibit greater antitumor efficiency when used as delivery vehicles in comparison with non-modified cells. For GM-BM-MSC, there is enough preclinical evidence showing the efficacy of IFN-β on solid tumor suppression to warrant the move to clinical trials. Indeed, by mid-2019 a trial involving up to 21 patients with advanced ovarian cancer is expected to provide the first ever data on the maximum tolerability and safety of MSC-IFN-β in humans . With rIn our effort to decode the diversity of MSC-based cancer cytotherapy outcomes, we methodically recorded and analyzed experimental data reported in the relevant literature. Our approach, although carefully designed, is far from perfect as it is based on a relatively limited number of observations that restrict the statistical resolution to the descriptive statistics level. Nevertheless, the trends obtained are representative and agree with the literature. In summary, our findings allow the following conclusions to be drawn: (a) more studies focusing on frequently occurring tumors are needed. This holds truth for both naïve and GM-MSC-based research work. For example, experimental data on naïve MSC targeting cancers such as hepatic, gastric and lung are rare, rendering any attempt to evaluate the MSC performance against the latter unsuccessful. Prioritizing these targets will provide more information towards a deeper understanding of the biology of MSC: tumor interactions, at the same time setting a solid basis for the development of more efficient MSC engineering protocols. Special emphasis should also be given on cancers for which there are preliminary studies with encouraging data that need confirmation, or there are no studies evaluating the anti-cancer performance of specific MSC types. These are pancreatic (naïve AT-/BM-MSC), colon and prostate (naïve and GM-UC-MSC), and brain cancers (GM-UC-MSC). (b) More attention should be paid to experimental design and implementation to minimize the technical heterogeneity, which comprises a major contributor for inconsistencies and erratic outcomes observed in experimental tumor cytotherapy. Experimental parameters such as the use of multiple cell lines to represent each tumor target, the MSC to cancer cell ratio, timing and mode of cell administration used, and, last but not least, the type of animal model adopted are of particular importance. (c) Genetic modification of MSC offers a significant advantage in anti-cancer efficacy over naïve MSC, successfully alleviating the bimodal effects of some MSC populations against certain tumors shifting the balance robustly toward tumor suppression and can become the new standard once the enabling technologies become safer. More focused clinical trials are needed towards this end. (d) Despite the omissions and inconsistencies, a critical mass of data from available studies so far suggest that the primary outcome of experimental cytotherapy is largely dictated by the biology of the interaction of the specific effector MSC with its target, with some MSC populations  generating a strong and robust tumoricidal response against specific tumors , while others (BM-MSC) are clearly unsuitable for use on the same target, since they display pro-tumorigenic behavior Tables  and 6. D.At this stage, any attempt to give a detailed account of the mediating mechanisms would be largely speculative, given the lack of studies focusing on the in vivo immunomodulatory effects of administered MSC within tumors, and the inadequacy of the present experimental models to recapitulate the multitude of highly plastic and bidirectional interactions that take place. Nevertheless, data patterns emerging from this meta-analysis  and safety , compared to their adult counterparts highlights UC-MSC as instrumental tools in cancer cytotherapy Table . ClearlyAdditional file 1:Figure S1. Comparison of research activity  on selected cancer treatment options over the last two decades. The four graphs (solid lines) depict the evolution of publication rates of journal articles reporting research work in PubMed on four types of therapies relative to cancer treatment  over a period of 20 years. Graphs are based on reported rates over seven 3-year periods, with a forward projection of one period (dashed trend line). In all four cases, the rates increase exponentially (y = a eb x); nevertheless, the growth for cancer cytotherapy publications (purple) occurs at a relatively higher rate as shown by the steeper trend line and higher value of b constant in the respective equation. This publication rate for MSC-based cancer cytotherapy studies has grown over sixfold faster, compared to that for combined chemotherapy, for example, rising from 1:100 to 1:15 over the last decade. This trend is suggestive of increased interest in this field that will most likely be sustained in the near future. PubMed search filters: English only, research articles only. (TIF 30030 kb)Additional file 2:Figure S2. Overview of meta-analysis methodology (TIF 12282 kb)Additional file 3:Figure S3. Example of a database form used to record experimental data used in the meta-analysis. Field titles correspond to the parameters comprising each of the in vitro and in vivo experiments as described in the methodology and results sections of the relevant articles. (TIF 9196 kb)Additional file 4:Figure S4. Distribution of the three most frequently associated tumors in relation to MSC effectors. Sample sizes: adipose-derived MSC (AT-MSC) = 32, bone marrow-derived MSC (BM-MSC) = 56, umbilical cord-derived MSC (UC-MSC) = 34. (TIF 4256 kb)Additional file 5:Figure S5. Comparison of distribution of anti-cancer effects for naïve MSC vs. naïve MSC used as control cells for genetically modified MSC-based cancer cytotherapy studies (Naïve + GM). Each of the 100% stacked columns shows the relative distribution of anti-cancer effect observed  (TIF 103676 kb)Additional file 6:Figure S6. List and frequency distribution of studies employing the use of genetically modified stem cells (GM-MSC) of human adipose tissue (AT), bone marrow (BM), and fetal umbilical cord (UC) matrix origin. In each row of the table, the length of black-gradient filled horizontal bars is proportional to the total number of studies  relevant to specific GM-MSC/tumor combinations; the list of respective citations is shown under the bars. Cancer types are ranked in descending order of world incidence (see also Fig.


S-nitrosation has been recognized as an important mechanism of protein posttranslational regulations, based on the attachment of a nitroso group to cysteine thiols. Reversible S-nitrosation, similarly to other redox-base modifications of protein thiols, has a profound effect on protein structure and activity and is considered as a convergence of signaling pathways of reactive nitrogen and oxygen species. In plant, S-nitrosation is involved in a wide array of cellular processes during normal development and stress responses. This review summarizes current knowledge on S-nitrosoglutathione reductase (GSNOR), a key enzyme which regulates intracellular levels of S-nitrosoglutathione (GSNO) and indirectly also of protein S-nitrosothiols. GSNOR functions are mediated by its enzymatic activity, which catalyzes irreversible GSNO conversion to oxidized glutathione within the cellular catabolism of nitric oxide. GSNOR is involved in the maintenance of balanced levels of reactive nitrogen species and in the control of cellular redox state. Multiple functions of GSNOR in plant development via NO-dependent and -independent signaling mechanisms and in plant defense responses to abiotic and biotic stress conditions have been uncovered. Extensive studies of plants with down- and upregulated GSNOR, together with application of transcriptomics and proteomics approaches, seem promising for new insights into plant S-nitrosothiol metabolism and its regulation. Nitric oxide (NO) is an important messenger included in many physiological processes. It is an uncharged, relatively stable free radical with unpaired electrons allowing diverse chemistry. Rapid reactions with other radicals including reactive oxygen species (ROSs)  lead to In general, the biosynthesis of NO in plants can proceed by pathways either oxidative or reductive, either enzymatic or non-enzymatic reactions, anyway depending on the site and the nature of stimulus for NO production ,4,5. TheS-nitrosothiols (SNOs) represent relatively a stable reserve and transport form of NO in vivo ,11. They2-dependent reaction of NO-derived RNSs and the major antioxidant tripeptide glutathione . GSNO is regarded to be an intracellular reservoir of NO bioactivity and a transport form of NO as well, even though NO and GSNO do not always interact with the same target proteins -2-oxoethyl)-1H-indole 2-carboxylicacid caused a significant increase in total RNSs and reduced germination propanoic acid further increases the level of antioxidant enzymes S-nitrosation and reverses seed germination inhibited by desiccation [The role of GSNOR and the regulation of intracellular SNO levels were studied in an NO accumulation mutant ( sativa) . NOE1 waiccation . Exposuriccation .A. thaliana and tobacco. The gene expression in both mentioned plant species is induced by salicylic acid (SA), a mediator of biotic stress. The following experiments with A. thaliana transgenic plants [Peronospora parasitica. Systemic acquired resistance (SAR) was demonstrated to be enhanced in plants under-expressing GSNOR and decreased in overexpressing plants; in agreement with the rate of GSNOR expression, the level of S-nitrosothiols changed in local and systemic leaves. The SAR signal transmission might be regulated by GSNOR through the vascular system, as the enzyme was found to be localized in the phloem. Taken together with the previous published data [NO and S-nitrosylated proteins are important signal molecules activating an immune response of plants to microbial pathogens. Thus, plant defense response to the pathogen is expected to be controlled by GSNOR, which manages NO/S-nitrosothiol homeostasis (reviewed in ). Díaz ec plants  describehed data , downreghed data . The hyphed data , where GA. thaliana plants exposed to diverse microbial pathogens, e.g., bacteria Pseudomonas syringae, powdery mildew Blumeria graminis, and downy mildew Hyaloperonospora parasitica. Basal disease resistance was strongly reduced in the absence of GSNOR, accompanied with reduced and delayed expression of SA-dependent genes, while non-host resistance was increased in A. thaliana mutants overexpressing GSNOR, accompanied with accelerated expression of SA-dependent genes [Helianthus annuus L.) cultivars with different sensitivity to the pathogen Plasmopara halstedii, susceptible and resistant ones [Cucumis spp. varying in susceptibility to biotrophic pathogen Golovinomyces cichoracearum [Rather opposing results, when GSNOR was proposed to be a positive regulator of plant immune responses suppressing pathogen growth early in the infection process, were described earlier by Feechan et al.  in A. thnt genes . The conant ones . After iracearum . SignifiPhytophthora infestans. Potato leaf treatment with SAR inducers β-aminobutyric acid (BABA) and laminarin decreased GSNOR activity and provoked accumulation of NO and ROSs. Pre-treatment with mentioned SAR inducers before inoculation with P. infestans by contrast increased GSNOR activity significantly, the S-nitrosothiol pool was depleted, and potato defense responses to the pathogen were enhanced, while non-inducer pre-treated plants showed unaltered enzymatic activity, a high level of S-nitrosothiols, and lower defense responses [Medicago truncatula after infection with Aphanomyces euteiches [M. truncatula against A. euteiches is connected with NO homeostasis, which is closely related with N nutrition.GSNOR might have an important role in NO-mediated biochemical modifications that subsequently lead to the more effective defense responses of potato plants to an attack of esponses . Interesuteiches . Data inNicotiana tabacum overexpressing γ-glutamylcysteine synthetase with higher glutathione levels, which have increased tolerance to biotrophic Pseudomonas syringae pv. tabaci [A. thaliana plants to Pseudomonas syringae pv. tomato [Nox1, a NO-overproducing mutant of A. thaliana [Nox1 and atgsnor1-1 (plant overexpressing GSNOR) or atgsnor1-3 (plant under-expressing GSNOR), the authors suggest that NO and GSNO control cellular processes in different ways via distinct or overlapping molecular targets.In the plant immune response, oxidoreductase TRXh5 was found to be an effective protein-SNO reductase, providing reversibility and specificity to signaling via protein-SNO . The dat. tabaci . GSNOR, . tomato . NO induthaliana . Those pInonotus obliquus and Phellinus morii might be, in future, employed for medicinal applications. Zhao et al. [Understanding of GSNOR, thioredoxin (TRX), and their roles during biosynthesis of phenylpropanoid-derived styrylpyrone polyphenols, components inhibiting tumor proliferation and reducing hypertension and various neurodegenerative disorders , in co-co et al.  describeA. thaliana to important agricultural crops is expected to be exploited through genetic manipulation of GSNOR levels to eventually achieve desired improvements in crop yields and stress tolerance.S-nitrosation has emerged among the key components of redox-based NO signaling that regulate the structure and activity of proteins through reversible post-translational modification of cysteine thiols. Despite the important advances in the understanding of the functions of S-nitrosation and S-nitrosothiols in plant metabolism and stress responses, major gaps in the picture of S-nitrosation on the intersection of signaling pathways of NO and ROSs still remain. Among them, the identification of NO sources and their localization contributing to S-nitrosation reactions in distinct tissues, cells, and subcellular compartments continues to be crucial in plant NO research in general. On the other hand, the mechanisms of in vivo regulations regarding the activity of GSNOR, and potentially of other more specific denitrosylases acting directly on proteins S-nitrosothiol, are still poorly described. Moreover, the development of highly specific and sensitive analytical tools to evaluate levels of both low molecular- and protein S-nitrosothiols will certainly contribute to advancement in the plant S-nitrosation field. Finally, the transfer of the knowledge obtained with model plants such as


Studies have reported relationships between psychological well-being and physical health in Western cultural contexts. However, longitudinal associations between well-being and health have not been examined in other cultures where different values and beliefs about well-being exist. This paper examined whether longitudinal profiles of well-being predict prospective health among Japanese adults. Data came from 654 people who completed two waves of the Midlife in Japan (MIDJA) Study collected 4–5 years apart. Health outcomes were assessed with subjective health, chronic conditions, physical symptoms, and functional health. The results showed that persistently high well-being predicted better health over time. High-arousal positive affect, which is relatively less valued in Japanese culture, was also associated with better health. The findings add cross-cultural evidence to the cross-time link between well-being and health. Psychological well-being is multifaceted including both eudaimonic  and hedonic  aspects. Psychological well-being has been shown to predict a wide array of health outcomes such as better subjective health , fewer cNotably missing in this literature is research from non-Western cultural contexts. This omission is important because psychological well-being is known to be shaped by cultural values and beliefs . Thus, iikigai, which refers to what makes life worth living. Ikigai is believed to be the most common indicator of psychological well-being in Japanese culture , and social and benevolent contribution. These elaborated ideas suggest possible overlap with other aspects of well-being such as personal growth and positive relations with others1. Pertinent to health, ikigai has repeatedly predicted better health in Japan, including lower mortality and incidence of functional disability . Individuals in Western cultures tend to experience self as an independent entity from their social surroundings, whereas self-concept in East Asian cultures is defined via one’s interdependent relations to other people . Within Such thinking converges with prior work showing cultural differences in associations between autonomy and positive affect with health. Another aspect of psychological well-being, self-acceptance, includes awareness of not only personal strengths but also weaknesses, which may parallel ideas of self-criticism emphasized in Japanese Confucianism as routes to self-improvement . SimilarEnvironmental mastery, another aspect of psychological well-being studied in the West, may be part of Japanese well-being, although for somewhat different reasons. Being in charge of one’s situation may be valued in Japan not so much in terms of having individual power to influence outcomes, but because of the aim of minimizing difficulties for others . Thus, tGuided by the above ideas, the purpose of this study was to investigate links between longitudinal profiles of differing aspects of psychological well-being among Japanese adults with distinct aspects of health, also studied across time. Drawing on previous findings with a United States sample , we focu2, autonomy, self-acceptance, environmental mastery), and two dimensions of hedonic wellbeing . Four separate measures of self-reported physical health were included: subjective health, chronic conditions, physical health symptoms, and functional health. The objective was to examine whether distinct dimensions of well-being mattered for all, or only some, aspects of cross-time health, thereby offering a comprehensive understanding of how persistently high versus persistently low well-being matters for unfolding profiles of physical health in Japanese adults.The indicators of well-being encompassed six dimensions of eudaimonic well-being  would be associated with health improvement across time in Japan. This prediction draws from prior literature suggesting cultural similarities in these areas of well-being, along with earlier evidence on their associations with health in Japan. Second, we hypothesized that persistently high autonomy and high-arousal positive affect would show weaker links to cross-time health, thus reflecting their reduced salience in the Japanese cultural context. Finally, two other aspects of well-being  did not include specific predictions, given the lack of theoretical or empirical guidelines from prior work.https://doi.org/10.3886/ICPSR30822.v3.Participants were from a large longitudinal survey Midlife in Japan (MIDJA), conducted in 2008 and 2012. The first wave  sampled 1,027 randomly selected adults residing in Tokyo metropolitan areas, aged 30–80. The second wave (MIDJA 2) was conducted in 2012–2013. Of the original 1,027 participants, 657 participants (70%) completed the longitudinal follow-up and are included in the following analyses. Details of the study protocol and data files are available on Eudaimonic well-being  includedHedonic well-being was measured by two types of positive affect. General/low-arousal positive affect was measured by We used four measures of physical health: (1) subjective health, measured by one item asking participants to rate their current health on a scale, ranging from 0 (worst) to 10 (best); (2) number of chronic conditions experienced in the past 12 months . The score was constructed by taking the total number of “Yes” responses (ranging from 0 to 30). (3) Frequency of health symptoms measured by aggregating the frequency of nine different symptoms  for the past 30 days  The alphas were 0.7 (Time 1) and 0.72 (Time 2). (4) Instrumental activities of daily living scale (IADL) measured functional health. Participants rated the extent to which their health limited various activities of daily living, ranging from basic activities  to vigorous activities  on a 4-point scale . Thus, higher scores indicated more functional limitations. The alphas were 0.89 for both time points.Demographic variables included age, gender , and level of education  were included. Consistent with findings from the United States , most MIThe core aim was to test whether persistently high versus low levels of psychological well-being would predict better physical health over 4–5 years. We conducted hierarchical linear regression analyses in which each measure of well-being predicted each measure of health outcome in a separate model. In the first step of the model, demographic variables and Time 1 baseline health were entered to predict Time 2 health. By including Time 1 health, the coefficients represent the associations between predictors and residualized changes in health from Time 1 to Time 2. In the next step, dummy-coded well-being was entered, in which stable high was used as a reference group compared to four other groups .The summary of results is displayed in R2Δ = 0.008, compared to other dimensions of eudaimonic well-being, R2Δ = 0.018–0.042.For all six scales of eudaimonic well-being, respondents with stable low profiles had worse subjective health at Time 2 compared to those with stable high profiles. For environmental mastery, personal growth, and positive relations with others, those with stable mid well-being also had worse health compared to those with stable high well-being. Autonomy explained smaller variances, R2Δ = 0.032, than high-arousal positive affect, R2Δ = 0.028.For both measures of hedonic well-being, those with stable low profiles showed worse health than those with stable high profiles. In addition, for general/low-arousal positive affect, those with stable mid profiles had worse health than those with stable high profiles. The effect size of general/low-arousal positive affect was slightly larger, R2Δ = 0.017, comparable with other dimensions .For all scales of eudaimonic well-being except for positive relations with others, those with stable low well-being reported more chronic conditions in 5 years compared to those with stable high well-being. Unlike subjective health, the effect size of autonomy was, R2Δ = 0.023, compared to high-arousal positive affect, R2Δ = 0.010.For both measures of hedonic well-being, those with stable low profiles reported greater increments in chronic conditions than those with stable high profiles. General/low-arousal positive affect explained more variance of the chronic conditions, The increase in health symptoms was greater for those with stable low well-being than those with stable high well-being, across all dimensions of eudaimonic well-being except personal growth. In additions, those with stable mid-levels of positive relations with others and autonomy had more health symptoms compared to those with the stable high-levels. Consistent with the results for chronic conditions, the effect size of autonomy was comparable to other dimensions of eudaimonic well-being. For hedonic well-being, neither general/low-arousal nor high-arousal positive affect predicted changes in health symptoms.Those with stable low well-being reported more physical limitations in daily activities than those with stable high well-being across all dimensions of eudaimonic well-being. For environmental mastery, autonomy, and self-acceptance, those with stable mid well-being had worse functional health compared to those with stable high well-being. Again, the effect size of autonomy was comparable to other dimensions of eudaimonic well-being.The association between hedonic well-being and functional health for daily activities showed a different pattern from other health outcomes. Cumulative profiles of high-arousal positive affect predicted greater increments in functional health whereas the profiles of general/low-arousal positive affect did not predict functional health. Those with stable high high-arousal positive affect reported relative improvement in functional health compared to those with stable low and stable mid high-arousal positive affect.The study yielded consistent patterns of results across dynamic measures of health that were predicted by cumulative profiles of diverse aspects of psychological well-being in Japanese adults. Specifically, persistently high levels of psychological well-being predicted improved subjective health, fewer chronic conditions, fewer health symptoms, and fewer functional health problems over 4–5 years compared to persistently low levels of psychological well-being. Persistently high levels of psychological well-being also predicted better subjective health, fewer health symptoms, and fewer functional limitations compared to persistently moderate levels of psychological well-being, suggesting that health improvement associated with higher psychological well-being may not be limited to those with extreme levels of psychological well-being. Together, the findings extend a prior literature focused on longitudinal associations between psychological well-being and health in United States adults to another cultural context, namely, Japan.For all six dimensions of eudaimonic well-being, Japanese adults with persistently high profiles of well-being showed greater health improvement  than those with stable low profiles of well-being. This was true even for autonomy, which is less culturally valued in in Japan compared to the United States It is notable that such effects were evident despite a notably shorter follow-up period in Japan (4–5 years) compared to the longer period (9–10 years) found for United States adults . Overallr = 0.68), it can be speculated that the effect of hedonic well-being on change in health may be more contingent on the stability of health measures than eudaimonic well-being.For hedonic well-being, persistently high levels of both low- and high-arousal positive affect predicted improved subjective health and fewer chronic conditions than persistently low levels of hedonic well-being. The results partially supported our hypotheses that high-arousal positive affect would show weaker association with health than general/low-arousal positive affect in Japan, except for functional health. These are consistent with prior research showing that low-arousal positive affect was more strongly associated with health than high-arousal positive affect in Japan . CumulatLastly, change in functional health was associated with only high-arousal positive affect. The different results for functional health could be attributed to that its measure included engagement in high-arousal activities . To investigate this possibility, we ran three separate models testing whether high-arousal positive affect measured at Time 1, Time 2, or the change between the two time points would predict Time 2 functional health . The only significant predictor was Time 2 high-arousal positive affect, indicating that the findings are accounted by the concurrent association between high-arousal positive affect and functional health, rather than the effect of high-arousal positive affect on health over time.Overall, psychological well-being accounted for small variances in Time 2 health. These small effect sizes were expected because the models predicted Time 2 health adjusted for Time 1 health; the residual changes in health were small between the relatively short interval . Nonetheless, the small effect sizes were comparable to prior studies with Western samples that examined the associations between psychological well-being and prospective health outcomes such as mortality and longevity , suggestThe key limitation of the study is that the analyses cannot rule out the reversed causality between well-being and health. Cumulative profiles of well-being were created based on Time 2 as well as baseline measure, which do not temporally precede Time 2 health. Thus, the associations between health and persistent levels of well-being could be partly due to the effect of health improvement on well-being. With the exception of the result for functional health and high arousal positive affect, however, the variance of Time 2 health  explained by cross-time well-being was greater than the variance of Time 2 well-being (net of Time 1 well-being) explained by cross-time health. This suggests that the observed associations were likely derived by the influence of cross-time well-being on health, though the alternative explanation cannot be rejected.In addition, the findings are based on single-sourced, self-reported measures of health. Although prior studies have shown that self-reported health including subjective health and chronic conditions are valid indicators of physical health e.g., , future Although comprehensive measures of well-being were employed, all were developed based on the theories formulated in the Western cultures. It is possible that these measures miss certain aspects of well-being specific to Japanese cultures. For instance, the study did not have an adequate measure of harmonious social relationships that receives a great emphasis in Japanese cultures. Although positive relations with others was included as an aspect of well-being, this measure focuses on perceptions of warm and trusting relationships  whereas Despite the limitations, the study is unique in that it examined multiple dimensions of psychological well-being to test longitudinal relationships between cumulative well-being and change in health in a different culture. The use of multi-dimensional approach is particularly important in considering cultural contexts, given that some dimensions have more cultural variation than others. Furthermore, by focusing on the stable levels of well-being, the study was able to examine health implications of well-being for which most people do not show reliable changes. The findings showed health predictability of persistent level of psychological well-being even when controlling for baseline health in Japan, highlighting the importance of cumulative psychological well-being in health benefits in diverse cultural contexts.The datasets generated for this study are available on request to the corresponding author.The studies involving human participants were reviewed and approved by the University of Wisconsin–Madison Institutional Review Board. The patients/participants provided their written informed consent to participate in this study.JY carried out the data analysis and drafted the manuscript under the supervision of CR. Both authors developed the study concept and approved the final version of the manuscript for submission.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Self-control is the ability to comply with a request, to postpone acting upon a desire object or goal, and to generate socially approved behavior in the absence of external monitors. Overeating is actually the failure in self-control while feeding. However, little is known about the brain function that allows individuals to consciously control their behavior in the context of food choice. To address this issue, we used functional MRI to measure brain activity among undergraduate young females. Forty-one undergraduate female students participated in the current study. Subjects underwent the food rating task, during which they rated each food item according to their subjective perception of its taste (from Dislike it very much to Like it very much), its long term effect on health  and decision strength to eat it (from Strong no to Strong yes). Behavioral results indicate the positive correlation between taste rating and its corresponding decision strength to eat, no matter the food is high caloric or low. Moreover, health ratings of high caloric food was negatively correlated with DEBQ-emotional eating, and taste ratings of high caloric food was positively correlated with DEBQ-external eating. Whole brain analysis of fMRI data indicates that BOLD responses in dlPFC were positively correlated with successful self-control; BOLD responses in midcingulate cortex were positively correlated with failed self-control. This study provided direct evidence that dlPFC was involved in self-control in food-related choice. We are living in an environment which promotes over-consumption of palatably high-energy food, and the obesity epidemic shows no signs of abating . IndividSelf-control has been variously defined as the ability to comply with a request, to initiate and cease activities according to situational demands, to modulate the intensity, frequency, and duration of verbal and motor acts in social and educational settings, to postpone acting upon a desire object or goal, and to generate socially approved behavior in the absence of external monitors . Self-coOvereating is actually the failure in self-control while feeding. High-sugar/high-fat food induce appetite-food reward, which drives food intake. Food reward is so strong that defect in self-control will, apparently, lead to overeating. Neuroimaging studies, using positron emission tomography (PET) and magnetic resonance imaging (MRI), which focused on food intake, yield valuable insights into the neurobiology underlying variation in regulation of food intake in human . RegulatNeuroimaging studies focusing on self-control found that cognitive control is the highest level of cognitive activity, and prefrontal lobe plays as the central role in cognitive control system –13. DiffContrary to the activity of self-control system, the brain reward system, containing vmPFC, lPFC, OFC, striatum, insula, anterior cingulum gyrus cortex, hippocampus, amygdale, and midbrain structures, encodes the subjective value of rewards and the subsequent impulse system, and it consistent with a role for this neuronal network in general hedonic representation , 19. RewAlong with previous literature, there is, apparently, an antagonistic effect between the self-control system represented by prefrontal area and the impulsive system represented by striatum. In a particular situation, intense activities in the prefrontal system indicate much weaker activities in the stratum system, and vice versa. It can be summarized that the balance between these two brain systems are vital to regulate feed behavior. Overeating and obesity will happen very likely if the balance is broken. We speculate that delicious high-fat food, which is difficult to resist and reject, may disturb the balance between the self-control system and the impulsive system. Previous studies mainly focused on the activities in stratum system while watching food pictures or the anticipating to intake food. Evidence in prefrontal control mechanism of feeding behavior is scarce. Hence, the current study, based on the activities of the prefrontal system while watching various food pictures, aimed to investigate the intrinsic mechanism underlying the self-control function in food-related decision-making. We employed three food rating tasks in the current study. In these tasks, subjects were required to indicate their decision intensity to consume the food items based on balancing the immediate pleasure from their taste and its long-term effect on health. We categorize subjects as high self-control group or low self-control group according to their score in food rating tasks. We hypothesized that: (1) increased dlPFC function would associate with self-control; (2) food picture would activate numbers of related areas, such as somatosensory cortex , visual cortex , primary taste cortex (insular), rewarding areas ; (3) activity differences would be observed between food-acceptation and food-rejection.Forty-three subjects participated in the current experiment . The demographic information of subjects was presented in Table Subjects completed a demographics questionnaire, including age, current and historic medications, and phase of menstrual cycle.not at all hungry”) to 4 (“very hungry”).Subjects rated current feelings of hunger on a 5-point Likert scale, ranging from 0  palatable food  and 85 picturing low-caloric (LC) food  were used in the current study. All of the stimuli were adopted from Chinese Food Picture Database . The fooDislike it very much, 2 = Dislike it, 3 = Like it, to 4 = Like it very much. And all health ratings were made on a 4-Likert scale from 1 = Very unhealthy, 2 = Unhealthy, 3 = Healthy, to 4 = Very healthy. Subjects were instructed to rate the taste without regard for its healthiness before the taste-rating block. Similarly, before the health-rating block they were instructed to rate the healthiness of each food item without regard for its taste. After the two rating blocks, subjects were presented with another food picture gallery including 10 food items , and they were asked to choose one food item as a reference item, which was relatively neutral on their taste and health perception.The food rating and decision-making task was similar with the task used in previous study . The tasStrong No (choose reference food), 2 = No (choose reference food), 3 = Yes (choose shown food), 4 = Strong Yes (choose shown food)  .The taste-rating task and decision-making task was done in the fMRI scanner and the health-rating task was done out of the scanner.2). Specifically, after the removal of shoes and coats, height was measured to the nearest millimeter using a stadiometer and weight was assessed to the nearest 0.1 kg using a digital scale. During the intake session, subjects signed the consent inform after reading a general overview of the study. Anthropometric measurements were then taken.Following approval from the Human Research Ethics Committee at School of Psychology, Southwest University, subjects were recruited via on-campus advertisements. Subsequently, 43 female undergraduate students engaged in the current study. All of the subjects took part in an intake session and one fMRI scanning session. Two sessions were conducted on separate days. Body weight and height was measured during the intake session. BMI was calculated as weight (in kilograms) divided by the squared height (in meters) of the subject  run was conducted. Then subjects completed the food taste rating runs and decision-making runs in the scanner, sequentially. Only the results from the decision-making task were reported here and the resting state fMRI data were reported in another study . Each su2, acquisition matrix = 64 × 64, in-plane resolution = 3 × 3mm2, 32 interleaved 3-mm-thick slices, inter-slice skip = 0.99 mm. Two volumes were discarded before the beginning of data collection in each run to allow for equilibration of the magnetic field.fMRI data were acquired using a 3-T Siemens Trio scanner in the SWU Imaging Center for Brain Research. Foam pads were used to reduce head movements and scanner noise. Scans were performed by an echo-planar imaging (EPI) sequence with the following scan parameters: repetition time = 2,000 ms, echo time = 30 ms, flip angle = 90°, field of view = 192 × 192 mm3, respectively. Functional time-series data were then detrended.Neuroimaging data were preprocessed using the SPM12 software  on the Matlab platform. For each subject, the first 10 volumes were discarded to account for signal equilibrium and subjects' adaptation to their immediate environment. Then, the fMRI images were corrected for the acquisition delay between slices and for the head motion. Two subjects were excluded because their head motion exceeded 2 mm in translation or 2° in rotation. Then, anatomical and functional images were normalized to the standard MNI template brain implemented in SPM12, resulting in voxel sizes of 1 and 3 mmFirstly, descriptive analysis was conducted with the demographic variables, DEBQ and behavioral ratings of the taste, health and decision making. Then, correlation analysis was conducted between decision strength of HC food or LC food, DEBQ-EM, and DEBQ-EX, respectively. We expected that decision strength-HC would positively correlate with DEBQ-EM and DEBQ-EX, while decision strength-LC would show no such correlation with these variables. According to behavior scores in both the food rating task and decision making task, we divided subjects into three groups: success in self-control (SSC), failure in self-control (FSC) and no self-control (NSC). SSC means rejection to like/healthy food and acceptation to dislike/healthy food; FSC means rejection to unlike/healthy food and acceptation to like/unhealthy food; NSC means rejection to unlike/unhealthy food and acceptation to like/healthy food.p < 0.05 and a minimum cluster size of 5 voxels.Analysis was performed with SPM12. Individual level whole brain general linear models (GLMs) and SPM12's standard hemodynamic response function was estimated in three steps. Firstly, we estimated the model separately for each individual. Three events were defined: (1) success in self-control (SSC) including choosing healthy-disliked food and rejecting unhealthy-liked food; (2) failure in self-control (FSC) including rejecting healthy-disliked food and choosing unhealthy-liked food; and (3) no self-control (NSC) including trials with healthy-liked food and unhealthy-disliked food. Secondly, we calculated contrast statistics at the individual level. Two main contrasts were specified for subject-level analysis: (1) SSC vs. FSC and (2) FSC vs. SSC. Thirdly, a general linear model was used to generate the statistical parametric maps for the second-level analysis, while BMI was introduced as a covariate variable in the analysis in the original manuscript. We expected that increased dlPFC function would associate with self-control. Main effects were considered significant using a whole-brain family wise error (FWE) of r = −0.32, p = 0.05); taste-likeness for high caloric food positively correlated with DEBQ-EX ; there is positive correlation between food liking and its corresponding eating choice, no matter the food is high caloric or low; health assessment of high caloric food negatively correlated with DEBQ-EM ; likeness assessment of high caloric food positively correlated with DEBQ-EX .The results of descriptive statistical analysis on three rating tasks were shown in Table We estimated a general linear model of brain responses in which activity during the entire evaluation period was modulated by self-control. Whole brain analysis showed that SSC vs. FSC significantly activated BOLD responses in DLPFC, whereas FSC vs. SSC significantly activated BOLD responses in midcingulate cortex (MCC) Table .Correlation analysis was performed with the SSC vs. FSC and FSC vs. SSC maps against individual's scores of three DEBQ subscales. However, no significant finding was obtained.Then, we divided SSC into two events at individual level: (1) choosing healthy-disliked food (SSC-C) and 2) rejecting unhealthy-liked food (SSC-R). Meanwhile, FSC were divided into two events at individual level: (1) choosing unhealthy-liked food (FSC-C) and (2) rejecting healthy-disliked food (FSC-R). Four main contrasts were specified for subject-level analysis: (1) SSC-R vs. FSC-R, (2) FSC-R vs. SSC-R, (3) SSC-C vs. FSC-C and 4) FSC-C vs. SSC-C. Correlational analysis were performed with the four contrast maps against individual's scores of three DEBQ subscales. Results showed that BOLD responses in bilateral putamen were positively correlated with DEBQ-R on SSC-R vs. FSC-R contrast. Meanwhile, BOLD responses in left MCC were positively correlated with DEBQ-R on FSC-C vs. SSC-C (Table  FSC-C vs rejectinBased on the reinforcement learning hypothesis of self-control and food decision making, this study provides an approach to characterize the association between self-control on food-related choice.As expected, self-control, which was indexed by the food choice between two food items, was positively correlated with BOLD responses in dlPFC. This is direct evidence showing the importance of dlPFC on self-control. Meanwhile, BOLD responses in MCC were positively correlated with unsuccessful self-control. These findings were in line with previous observations of the positive association between dlPFC with inhibition to energy intake , or smokUnder the “rejection” conditions, BOLD responses in bilateral putamen were positively correlated with DEBQ-R, no matter it's successful or unsuccessful self-control; Under the “acceptation” conditions, responses in MCC, unilaterally, were positively correlated with DEBQ-R, no matter it's successful or unsuccessful self-control. Although activities can be observed under both condition, we speculate there may exist difference between them, which implying different neuromechanisms between “accepting” food and “rejecting” food. Cingulate gyrus is crucial structure functioning in the regulation system . NeuroimInterestingly, fMRI results in the current study also confirmed that DEBQ scores had positive correlation with BOLD responses in putamen, bilaterally, no matter self-control is successful or unsuccessful. Studies concerning restrained eating verify that high score of DEBQ reveals stronger cognitive control while in feeding environment, which, consequently, lead to restricted eating behavior . BesidesThis study was carried out in accordance with the recommendations of The Regulations of Ethical Reviews of Biomedical Research Involving Human, Ministry of Health, China. The protocol was approved by the Ethic Committee of Faculty of Psychology, Southwest University. All subjects gave written informed consent in accordance with the Declaration of Helsinki.FC: wrote this manuscript. YZ and YH: analyzed the data. QH: edited the manuscript and did the proof reading. XG: designed this study and got the funding.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.