How to obtain an integrated picture of the molecular networks involved in adaptation to microgravity in different biological systems?

Periodically, the European Space Agency (ESA) updates scientific roadmaps in consultation with the scientific community. The ESA SciSpacE Science Community White Paper (SSCWP) 9, "Biology in Space and Analogue Environments", focusses in 5 main topic areas, aiming to address key community-identified knowledge gaps in Space Biology. Here we present one of the identified topic areas, which is also an unanswered question of life science research in Space: "How to Obtain an Integrated Picture of the Molecular Networks Involved in Adaptation to Microgravity in Different Biological Systems?" The manuscript reports the main gaps of knowledge which have been identified by the community in the above topic area as well as the approach the community indicates to address the gaps not yet bridged. Moreover, the relevance that these research activities might have for the space exploration programs and also for application in industrial and technological fields on Earth is briefly discussed.

How are cell and tissue structure and function influenced by gravity and what are the gravity perception mechanisms?

Progress in mechanobiology allowed us to better understand the important role of mechanical forces in the regulation of biological processes. Space research in the field of life sciences clearly showed that gravity plays a crucial role in biological processes. The space environment offers the unique opportunity to carry out experiments without gravity, helping us not only to understand the effects of gravitational alterations on biological systems but also the mechanisms underlying mechanoperception and cell/tissue response to mechanical and gravitational stresses. Despite the progress made so far, for future space exploration programs it is necessary to increase our knowledge on the mechanotransduction processes as well as on the molecular mechanisms underlying microgravity-induced cell and tissue alterations. This white paper reports the suggestions and recommendations of the SciSpacE Science Community for the elaboration of the section of the European Space Agency roadmap "Biology in Space and Analogue Environments" focusing on "How are cells and tissues influenced by gravity and what are the gravity perception mechanisms?" The knowledge gaps that prevent the Science Community from fully answering this question and the activities proposed to fill them are discussed.

Modeled microgravity unravels the roles of mechanical forces in renal progenitor cell physiology

BACKGROUND

The glomerulus is a highly complex system, composed of different interdependent cell types that are subjected to various mechanical stimuli. These stimuli regulate multiple cellular functions, and changes in these functions may contribute to tissue damage and disease progression. To date, our understanding of the mechanobiology of glomerular cells is limited, with most research focused on the adaptive response of podocytes. However, it is crucial to recognize the interdependence between podocytes and parietal epithelial cells, in particular with the progenitor subset, as it plays a critical role in various manifestations of glomerular diseases. This highlights the necessity to implement the analysis of the effects of mechanical stress on renal progenitor cells.

METHODS

Microgravity, modeled by Rotary Cell Culture System, has been employed as a system to investigate how renal progenitor cells respond to alterations in the mechanical cues within their microenvironment. Changes in cell phenotype, cytoskeleton organization, cell proliferation, cell adhesion and cell capacity for differentiation into podocytes were analyzed.

RESULTS

In modeled microgravity conditions, renal progenitor cells showed altered cytoskeleton and focal adhesion organization associated with a reduction in cell proliferation, cell adhesion and spreading capacity. Moreover, mechanical forces appeared to be essential for renal progenitor differentiation into podocytes. Indeed, when renal progenitors were exposed to a differentiative agent in modeled microgravity conditions, it impaired the acquisition of a complex podocyte-like F-actin cytoskeleton and the expression of specific podocyte markers, such as nephrin and nestin. Importantly, the stabilization of the cytoskeleton with a calcineurin inhibitor, cyclosporine A, rescued the differentiation of renal progenitor cells into podocytes in modeled microgravity conditions.

CONCLUSIONS

Alterations in the organization of the renal progenitor cytoskeleton due to unloading conditions negatively affect the regenerative capacity of these cells. These findings strengthen the concept that changes in mechanical cues can initiate a pathophysiological process in the glomerulus, not only altering podocyte actin cytoskeleton, but also extending the detrimental effect to the renal progenitor population. This underscores the significance of the cytoskeleton as a druggable target for kidney diseases.

How do gravity alterations affect animal and human systems at a cellular/tissue level?

The present white paper concerns the indications and recommendations of the SciSpacE Science Community to make progress in filling the gaps of knowledge that prevent us from answering the question: "How Do Gravity Alterations Affect Animal and Human Systems at a Cellular/Tissue Level?" This is one of the five major scientific issues of the ESA roadmap "Biology in Space and Analogue Environments". Despite the many studies conducted so far on spaceflight adaptation mechanisms and related pathophysiological alterations observed in astronauts, we are not yet able to elaborate a synthetic integrated model of the many changes occurring at different system and functional levels. Consequently, it is difficult to develop credible models for predicting long-term consequences of human adaptation to the space environment, as well as to implement medical support plans for long-term missions and a strategy for preventing the possible health risks due to prolonged exposure to spaceflight beyond the low Earth orbit (LEO). The research activities suggested by the scientific community have the aim to overcome these problems by striving to connect biological and physiological aspects in a more holistic view of space adaptation effects.

Optimization of an Ex-Vivo Human Skin/Vein Model for Long-Term Wound Healing Studies: Ground Preparatory Activities for the 'Suture in Space' Experiment Onboard the International Space Station

This study is preliminary to an experiment to be performed onboard the International Space Station (ISS) and on Earth to investigate how low gravity influences the healing of sutured human skin and vein wounds. Its objective was to ascertain whether these tissue explants could be maintained to be viable ex vivo for long periods of time, mimicking the experimental conditions onboard the ISS. We developed an automated tissue culture chamber, reproducing and monitoring the physiological tensile forces over time, and a culture medium enriched with serelaxin (60 ng/mL) and (Zn(PipNONO)Cl) (28 ng/mL), known to extend viability of explanted organs for transplantation. The results show that the human skin and vein specimens remained viable for more than 4 weeks, with no substantial signs of damage in their tissues and cells. As a further clue about cell viability, some typical events associated with wound repair were observed in the tissue areas close to the wound, namely remodeling of collagen fibers in the papillary dermis and of elastic fibers in the vein wall, proliferation of keratinocyte stem cells, and expression of the endothelial functional markers eNOS and FGF-2. These findings validate the suitability of this new ex vivo organ culture system for wound healing studies, not only for the scheduled space experiment but also for applications on Earth, such as drug discovery purposes.

Role of fibroblasts in wound healing and tissue remodeling on Earth and in space

Wound healing (WH) and the role fibroblasts play in the process, as well as healing impairment and fibroblast dysfunction, have been thoroughly reviewed by other authors. We treat these topics briefly, with the only aim of contextualizing the true focus of this review, namely, the microgravity-induced changes in fibroblast functions involved in WH. Microgravity is a condition typical of spaceflight. Studying its possible effects on fibroblasts and WH is useful not only for the safety of astronauts who will face future interplanetary space missions, but also to help improve the management of WH impairment on Earth. The interesting similarity between microgravity-induced alterations of fibroblast behavior and fibroblast dysfunction in WH impairment on Earth is highlighted. The possibility of using microgravity-exposed fibroblasts and WH in space as models of healing impairment on Earth is suggested. The gaps in knowledge on fibroblast functions in WH are analyzed. The contribution that studies on fibroblast behavior in weightlessness can make to fill these gaps and, consequently, improve therapeutic strategies is considered.

Space Flight-Promoted Insulin Resistance as a Possible Disruptor of Wound Healing

During space flight, especially when prolonged, exposure to microgravity results in a number of pathophysiological changes such as bone loss, muscle atrophy, cardiovascular and metabolic changes and impaired wound healing, among others. Interestingly, chronic low-grade inflammation and insulin resistance appear to be pivotal events linking many of them. Interestingly, real and experimental microgravity is also associated to altered wound repair, a process that is becoming increasingly important in view of prolonged space flights. The association of insulin resistance and wound healing impairment may be hypothesized from some dysmetabolic conditions, like the metabolic syndrome, type 2 diabetes mellitus and abdominal/visceral obesity, where derangement of glucose and lipid metabolism, greater low-grade inflammation, altered adipokine secretion and adipocyte dysfunction converge to produce systemic effects that also negatively involve wound healing. Indeed, wound healing impairment after traumatic events and surgery in space remains a relevant concern for space agencies. Further studies are required to clarify the molecular connection between insulin resistance and wound healing during space flight, addressing the ability of physical, endocrine/metabolic, and pharmacological countermeasures, as well as nutritional strategies to prevent long-term detrimental effects on tissue repair linked to insulin resistance. Based on these considerations, this paper discusses the pathophysiological links between microgravity-associated insulin resistance and impaired wound healing.

Exploitation of Skin Microbiota in Wound Healing: Perspectives During Space Missions

Wound healing is slowed in Space. Microgravity and possible physical factors associated with Space affect alterations in fibroblast, matrix formation, dysregulation in apoptosis and inflammation. The microbial populations settled on skin, space modules, in space suits, are also playing a pivotal role, as wound healing is also affected by the microbial community. We propose a perspective that includes four domines for the application of human skin microbiota for wound healing in Space: The natural antimicrobial properties of the skin microbiota, the crosstalk of the skin microbiota with the immune system during wound healing, the contribution of the microbiota in precision medicine, and the role of gut-skin and gut-brain axes. A stronger understanding of the connections and metabolic network among bacteria, fungi, the host’s immune system and the host metabolism will support the basis for a better wound healing in Space.

Physiological adaptations affecting drug pharmacokinetics in space: what do we really know? A critical review of the literature

As human spaceflight progresses with extended mission durations, the demand for effective and safe drugs will necessarily increase. To date, the accepted medications used during missions (for space motion sickness, sleep disturbances, allergies, pain, and sinus congestion) are administered under the assumption that they act as safely and efficaciously as on Earth. However, physiological changes have been documented in human subjects in spaceflight involving fluid shifts, muscle and bone loss, immune system dysregulation, and adjustments in the gastrointestinal tract and metabolism. These alterations may change the pharmacokinetics (PK) and pharmacodynamics of commonly used medications. Frustratingly, the information gained from bed rest studies and from in‐flight observations is incomplete and also demonstrates a high variability in drug PK. Therefore, the objectives of this review are to report (i) the impact of the space environmental stressors on human physiology in relation to PK; (ii) the state‐of‐the‐art on experimental data in space and/or in ground‐based models; (iii) the validation of ground‐based models for PK studies; and (iv) the identification of research gaps.

The Future of Personalized Medicine in Space: From Observations to Countermeasures

The aim of personalized medicine is to detach from a “one-size fits all approach” and improve patient health by individualization to achieve the best outcomes in disease prevention, diagnosis and treatment. Technological advances in sequencing, improved knowledge of omics, integration with bioinformatics and new in vitro testing formats, have enabled personalized medicine to become a reality. Individual variation in response to environmental factors can affect susceptibility to disease and response to treatments. Space travel exposes humans to environmental stressors that lead to physiological adaptations, from altered cell behavior to abnormal tissue responses, including immune system impairment. In the context of human space flight research, human health studies have shown a significant inter-individual variability in response to space analogue conditions. A substantial degree of variability has been noticed in response to medications (from both an efficacy and toxicity perspective) as well as in susceptibility to damage from radiation exposure and in physiological changes such as loss of bone mineral density and muscle mass in response to deconditioning. At present, personalized medicine for astronauts is limited. With the advent of longer duration missions beyond low Earth orbit, it is imperative that space agencies adopt a personalized strategy for each astronaut, starting from pre-emptive personalized pre-clinical approaches through to individualized countermeasures to minimize harmful physiological changes and find targeted treatment for disease. Advances in space medicine can also be translated to terrestrial applications, and vice versa. This review places the astronaut at the center of personalized medicine, will appraise existing evidence and future preclinical tools as well as clinical, ethical and legal considerations for future space travel.

Effect of space flight on the behavior of human retinal pigment epithelial ARPE-19 cells and evaluation of coenzyme Q10 treatment

Astronauts on board the International Space Station (ISS) are exposed to the damaging effects of microgravity and cosmic radiation. One of the most critical and sensitive districts of an organism is the eye, particularly the retina, and > 50% of astronauts develop a complex of alterations designated as spaceflight-associated neuro-ocular syndrome. However, the pathogenesis of this condition is not clearly understood. In the current study, we aimed to explore the cellular and molecular effects induced in the human retinal pigment ARPE-19 cell line by their transfer to and 3-day stay on board the ISS in the context of an experiment funded by the Agenzia Spaziale Italiana. Treatment of cells on board the ISS with the well-known bioenergetic, antioxidant, and antiapoptotic coenzyme Q10 was also evaluated. In the ground control experiment, the cells were exposed to the same conditions as on the ISS, with the exception of microgravity and radiation. The transfer of ARPE-19 retinal cells to the ISS and their living on board for 3 days did not affect cell viability or apoptosis but induced cytoskeleton remodeling consisting of vimentin redistribution from the cellular boundaries to the perinuclear area, underlining the collapse of the network of intermediate vimentin filaments under unloading conditions. The morphological changes endured by ARPE-19 cells grown on board the ISS were associated with changes in the transcriptomic profile related to the cellular response to the space environment and were consistent with cell dysfunction adaptations. In addition, the results obtained from ARPE-19 cells treated with coenzyme Q10 indicated its potential to increase cell resistance to damage.

NIR Laser Photobiomodulation Induces Neuroprotection in an In Vitro Model of Cerebral Hypoxia/Ischemia

Brain photobiomodulation (PBM) is an innovative treatment for a variety of neurological conditions, including cerebral ischemia. However, the capability of PBM for ischemic stroke needs to be further explored and its mechanisms of action remain currently unclear. The aim of the present research was to identify a treatment protocol capable of inducing neuroprotection and to investigate the molecular mechanisms activated by a dual-wavelength near infrared (NIR) laser source in an organotypic hippocampal slice model of hypoxia/ischemia. Hippocampal slices were exposed to oxygen and glucose deprivation (OGD) for 30 min followed by NIR laser light (fluence 3.71, 7.42, or 14.84 J/cm²; wavelengths 808 nm and 905 nm) delivered immediately or 30 min or 60 min after OGD, in order to establish a therapeutic window. Neuronal injury was assessed by propidium iodide fluorescence 24 h later. Our results show that NIR laser irradiation attenuates OGD neurotoxicity once applied immediately or 30 min after OGD. Western blot analysis of proteins involved in neuroinflammation (iNOS, COX-2, NFkB subunit p65, and Bcl-2) and in glutamatergic-mediated synaptic activity (vGluT1, EAAT2, GluN1, and PSD95) showed that the protein modifications induced by OGD were reverted by NIR laser application. Moreover, CA1 confocal microscopy revealed that the profound morphological changes induced by OGD were reverted by NIR laser radiation. In conclusion, NIR laser radiation attenuates OGD neurotoxicity in organotypic hippocampal slices through attenuation of inflammatory mechanisms. These findings shed light on molecular definition of NIR neuroprotective mechanisms, thus underlining the potential benefit of this technique for the treatment of cerebral ischemia.

Evaluation of Adjunctive Photobiomodulation (PBMT) for COVID-19 Pneumonia via Clinical Status and Pulmonary Severity Indices in a Preliminary Trial

PURPOSE

Evidence-based and effective treatments for COVID-19 are limited, and a new wave of infections and deaths calls for novel, easily implemented treatment strategies. Photobiomodulation therapy (PBMT) is a well-known adjunctive treatment for pain management, wound healing, lymphedema, and cellulitis. PBMT uses light to start a cascade of photochemical reactions that lead to local and systemic anti-inflammatory effects at multiple levels and that stimulate healing. Numerous empirical studies of PBMT for patients with pulmonary disease such as pneumonia, COPD and asthma suggest that PBMT is a safe and effective adjunctive treatment. Recent systematic reviews suggest that PBMT may be applied to target lung tissue in COVID-19 patients. In this preliminary study, we evaluated the effect of adjunctive PBMT on COVID-19 pneumonia and patient clinical status.

PATIENTS AND METHODS

We present a small-scale clinical trial with 10 patients randomized to standard medical care or standard medical care plus adjunctive PBMT. The PBMT group received four daily sessions of near-infrared light treatment targeting the lung tissue via a Multiwave Locked System (MLS) laser. Patient outcomes were measured via blood work, chest x-rays, pulse oximetry and validated scoring tools for pneumonia.

RESULTS

PBMT patients showed improvement on pulmonary indices such as SMART-COP, BCRSS, RALE, and CAP (Community-Acquired Pneumonia questionnaire). PBMT-treated patients showed rapid recovery, did not require ICU admission or mechanical ventilation, and reported no long-term sequelae at 5 months after treatment. In the control group, 60% of patients were admitted to the ICU for mechanical ventilation. The control group had an overall mortality of 40%. At a 5-month follow-up, 40% of the control group experienced long-term sequelae.

CONCLUSION

PBMT is a safe and effective potential treatment for COVID-19 pneumonia and improves clinical status in COVID-19 pneumonia.

A 57-Year-Old African American Man with Severe COVID-19 Pneumonia Who Responded to Supportive Photobiomodulation Therapy (PBMT): First Use of PBMT in COVID-19

Patient: Male, 57-year-old

Final Diagnosis: COVID-19

Symptoms: Shortness of breath • hypoxia

Medication: —

Clinical Procedure: Photobiomodulation therapy (PBMT)

Specialty: Infectious Diseases • Pulmonology

Effect of Unloading Condition on the Healing Process and Effectiveness of Platelet Rich Plasma as a Countermeasure: Study on In Vivo and In Vitro Wound Healing Models

Wound healing is a very complex process that allows organisms to survive injuries. It is strictly regulated by a number of biochemical and physical factors, mechanical forces included. Studying wound healing in space is interesting for two main reasons: (i) defining tools, procedures, and protocols to manage serious wounds and burns eventually occurring in future long-lasting space exploration missions, without the possibility of timely medical evacuation to Earth; (ii) understanding the role of gravity and mechanical factors in the healing process and scarring, thus contributing to unravelling the mechanisms underlying the switching between perfect regeneration and imperfect repair with scarring. In the study presented here, a new in vivo sutured wound healing model in the leech (Hirudo medicinalis) has been used to evaluate the effect of unloading conditions on the healing process and the effectiveness of platelet rich plasma (PRP) as a countermeasure. The results reveal that microgravity caused a healing delay and structural alterations in the repair tissue, which were prevented by PRP treatment. Moreover, investigating the effects of microgravity and PRP on an in vitro wound healing model, it was found that PRP is able to counteract the microgravity-induced impairment in fibroblast migration to the wound site. This could be one of the mechanisms underlying the effectiveness of PRP in preventing healing impairment in unloading conditions.

Effect of NIR laser therapy by MLS-MiS source against neuropathic pain in rats: in vivo and ex vivo analysis

Neuropathic pain is characterized by an uncertain etiology and by a poor response to common therapies. The ineffectiveness and the frequent side effects of the drugs used to counteract neuropathic pain call for the discovery of new therapeutic strategies. Laser therapy proved to be effective for reducing pain sensitivity thus improving the quality of life. However, its application parameters and efficacy in chronic pain must be further analyzed. We investigated the pain relieving and protective effect of Photobiomodulation Therapy in a rat model of compressive mononeuropathy induced by Chronic Constriction Injury of the sciatic nerve (CCI). Laser (MLS-MiS) applications started 7 days after surgery and were performed ten times over a three week period showing a reduction in mechanical hypersensitivity and spontaneous pain that started from the first laser treatment until the end of the experiment. The ex vivo analysis highlighted the protective role of laser through the myelin sheath recovery in the sciatic nerve, inhibition of iNOS expression and enhancement of EAAT-2 levels in the spinal cord. In conclusion, this study supports laser treatment as a future therapeutic strategy in patients suffering from neuropathic pain induced by trauma.

Glyoxylate cycle activity in Pinus pinea seeds during germination in altered gravity conditions

This work inserts in the research field regarding the effects of altered gravity conditions on biological plant processes. Pinus pinea seeds germination was studied in simulated microgravity (2x10^-3g) and hypergravity (20g) conditions. The effects of simulated gravity were evaluated monitoring the levels of the key enzymes, involved in the main metabolic pathway during germination process of lipid-rich seeds (oilseeds): isocitrate lyase and malate synthase for glyoxylate cycle, 3-hydroxyacyl-CoA dehydrogenase for beta-oxidation, isocitrate dehydrogenase for Krebs cycle, pyruvate kinase for glycolysis and glucose 6 phosphate dehydrogenase for pentose phosphate shunt. The simulated micro and hypergravity conditions were obtained by a Random Position Machine and a Hyperfuge, respectively. Results show that the levels of some tested enzymes, at different lag times of the germination process, have the same trend of controls (g = 1), but with significant differences from quantitative point of view. They are higher in microgravity conditions and lower in hypergravity ones, suggesting that, from a biochemical point of view, the germination process results accelerated in microgravity conditions and delayed in hypergravity ones. These biochemical results show a good correlation with morphological ones, obtained with the measurement of the length of the seeds sprouting radicle. These results give promising indications regarding the possibility to grow plant with lipid-rich seeds in spatial environment, to obtain food sources for astronauts during long term space missions and to reconstitute new atmosphere.

Body composition and metabolic changes during a 520-day mission simulation to Mars

PURPOSE

The "Mars-500 project" allowed to evaluate the changes in psychological/physiological adaptation over a prolonged confinement, in order to gather information for future missions. Here, we evaluated the impact of confinement and isolation on body composition, glucose metabolism/insulin resistance and adipokine levels.

METHODS

The "Mars-500 project" consisted of 520 consecutive days of confinement from June 3, 2010 to Nov 4, 2011. The crew was composed of six male subjects (three Russians, two Europeans, and one Chinese) with a median age of 31 years (range 27-38 years).

RESULTS

During the 520-day confinement, total body mass and BMI progressively decreased, reaching a significant difference at the end (417 days) of the observation period (- 9.2 and - 5.5%, respectively). Fat mass remained unchanged. A progressive and significant increase of fasting plasma glucose was observed between 249 and 417 days (+ 10/+ 17% vs baseline), with a further increase at the end of confinement (up to + 30%). Median plasma insulin showed a non-significant early increment (60 days; + 86%). Total adiponectin halved (- 47%) 60 days after hatch closure, remaining at this nadir (- 51%) level for a further 60 days. High molecular weight adiponectin remained significantly lower from 60 to 168 days.

CONCLUSIONS

Based on these data, countermeasures may be envisioned to balance the potentially harmful effects of prolonged confinement, including a better exercise program, with accurate monitoring of (1) the individual activity and (2) the relationship between body composition and metabolic derangement.

Continuous Exposure to Simulated Hypergravity-Induced Changes in Proliferation, Morphology, and Gene Expression of Human Tendon Cells

Gravity influences physical and biological processes, especially during development and homeostasis of several tissues in the human body. Studies under altered gravity have been receiving great attention toward a better understanding of microgravity-, hypogravity (<1 g)-, or hypergravity (>1 g)-induced alterations. In this work, the influence of simulated hypergravity over human tendon-derived cells (hTDCs) was studied at 5, 10, 15, and 20 g for 4 or 16 h, using a large diameter centrifuge. Main results showed that 16 h of simulated hypergravity limited cell proliferation. Cell area was higher in hTDCs cultured at 5, 10, and 15 g for 16 h, in comparison to 1 g control. Actin filaments were more pronounced in hTDCs cultured at 5 and 10 g for 16 h. Focal adhesion kinase (FAK) was mainly expressed in focal adhesion sites upon hypergravity stimulation, in comparison to perinuclear localization in control cells after 16 h; and FAK number/cell increased with increasing g-levels. A tendency toward an upregulation of tenogenic markers was observed; scleraxis (SCX), tenascin C (TNC), collagen type III (COL3A1), and decorin (DCN) were significantly upregulated in hTDCs cultured at 15 g and COL3A1 and DCN were significantly upregulated in hTDCs cultured at 20 g. Overall, simulated hypergravity affected the behavior of hTDCs, with more pronounced effects in the long-term period (16 h) of stimulation.

A comparison trial between three treatment modalities for the management of myofascial pain of jaw muscles: A preliminary study

OBJECTIVES

To compare three treatment modalities for the management of myofascial pain of jaw muscles.

METHODS

Thirty (N = 30) patients with low pain-related impairment were randomly assigned to receive laser therapy (LST), oral appliance therapy (OA), or counseling (CSL). Visual Analog Scale (VAS) pain levels and the Muscular Index (MI) of the Craniomandibular Index were the outcome variables, which were assessed at baseline, at three weeks, three months, and six months.

RESULTS

At six months, improvement in the MI was maintained both in the LST (p = .025) and OA groups (p < .001). As for VAS values, positive changes were still shown for LST (p = .001), and were also shown for the OA (p = .002) and CSL groups (p = .048).

CONCLUSIONS

Despite differences in the short-term effectiveness of LST and OA, with respect to CSL alone, all three treatment groups improved at six months. This suggests that active treatments should be directed to maximize the positive changes in the short-term period.

Effects of extremely low-frequency magnetotherapy on proliferation of human dermal fibroblasts

Extremely low-frequency electromagnetic fields (ELF-EMFs) applied in magnetotherapy have frequency lower than 100 Hz and magnetic field intensity ranging from 0.1 to 20 mT. For many years, the use of magnetotherapy in clinics has been increasing because of its beneficial effects in many processes, e.g., skin diseases, inflammation and bone disorders. However, the understanding of the microscopic mechanisms governing such processes is still lacking and the results of the studies on the effects of ELF-EMFs are controversial because effects derive from different conditions and from intrinsic responsiveness of different cell types.In the present study, we studied the biological effects of 1.5 h exposure of human dermal fibroblasts to EMFs with frequencies of 5 and 50 Hz and intensity between 0.25 and 1.6 mT. Our data showed that the magnetic treatment did not produce changes in cell viability, but gave evidence of a sizeable decrease in proliferation at 24 h after treatment. In addition, immunofluorescence experiments displayed an increase in tubulin expression that could foreshadow changes in cell motility or morphology. The decrease in proliferation with unchanged viability and increase in tubulin expression could be consistent with the triggering of a transdifferentiation process after the exposure to ELF-EMFs.

Low extracellular sodium promotes adipogenic commitment of human mesenchymal stromal cells: a novel mechanism for chronic hyponatremia-induced bone loss

Hyponatremia represents an independent risk factor for osteoporosis and fractures, affecting both bone density and quality. A direct stimulation of bone resorption in the presence of reduced extracellular sodium concentrations ([Na(+)]) has been shown, but the effects of low [Na(+)] on osteoblasts have not been elucidated. We investigated the effects of a chronic reduction of extracellular [Na(+)], independently of osmotic stress, on human mesenchymal stromal cells (hMSC) from bone marrow, the common progenitor for osteoblasts and adipocytes. hMSC adhesion and viability were significantly inhibited by reduced [Na(+)], but their surface antigen profile and immuno-modulatory properties were not altered. In low [Na(+)], hMSC were able to commit toward both the osteogenic and the adipogenic phenotypes, as demonstrated by differentiation markers analysis. However, the dose-dependent increase in the number of adipocytes as a function of reduced [Na(+)] suggested a preferential commitment toward the adipogenic phenotype at the expense of osteogenesis. The amplified inhibitory effect on the expression of osteoblastic markers exerted by adipocytes-derived conditioned media in low [Na(+)] further supported this observation. The analysis of cytoskeleton showed that low [Na(+)] were associated with disruption of tubulin organization in hMSC-derived osteoblasts, thus suggesting a negative effect on bone quality. Finally, hMSC-derived osteoblasts increased their expression of factors stimulating osteoclast recruitment and activity. These findings confirm that hyponatremia should be carefully taken into account because of its negative effects on bone, in addition to the known neurological effects, and indicate for the first time that impaired osteogenesis may be involved.

Effects of near-infrared laser radiation on the survival and inflammatory potential of Candida spp. involved in the pathogenesis of chemotherapy-induced oral mucositis

Candida spp. usually colonize ulcerative lesions of atrophic mucosa in patients with chemotherapy-induced oral mucositis inducing severe inflammation. The spread of antifungal-resistant strains strongly encouraged the search of complementary or alternative therapeutic strategies to cure inflamed mucosa. In this paper, we studied the effects of a near-infrared (NIR) laser system with dual-wavelength emission (808 nm + 904 nm) on the survival and inflammatory potential of C. albicans, C. glabrata, and C. parapsilosis. Laser treatment was performed with a Multiwave Locked System laser. Survival and apoptosis of fungal strains were evaluated by colony-forming units (CFU) counting and annexin V staining. Cytokine production was evaluated by ImmunoPlex array. Laser treatment significantly affected the survival of Candida spp. by inducing apoptosis and induced a lower production of inflammatory cytokines by dendritic cells compared to untreated fungi. No differences in the survival and inflammatory potential were recorded in treated or untreated Saccharomyces cerevisiae cells, used as the control non-pathogenic microorganism. Laser treatment altered the survival and inflammatory potential of pathogenic Candida spp. These data provide experimental support to the use of NIR laser radiation as a co-adjuvant of antifungal therapy in patients with oral mucositis (OM) complicated by Candida infections.

Effect of IR laser on myoblasts: a proteomic study

Laser therapy is used in physical medicine and rehabilitation to accelerate muscle recovery and in sports medicine to prevent damages produced by metabolic disturbances and inflammatory reactions after heavy exercise. The aim of this research was to get insight into possible benefits deriving from the application of an advanced IR laser system to counteract deficits of muscle energy metabolism and stimulate the recovery of hypotrophic tissue. We studied the effect of IR laser treatment on proliferation, differentiation, cytoskeleton organization and global protein expression in C2C12 myoblasts. We found that laser treatment induced a decrease in the cell proliferation rate without affecting cell viability, while leading to cytoskeletal rearrangement and expression of the early differentiation marker MyoD. The differential proteome analysis revealed the up-regulation and/or modulation of many proteins known to be involved in cell cycle regulation, cytoskeleton organization and differentiation.

Colonic and gastric cancer metastatic lymph nodes: applications of autofluorescence-based techniques

Lymphadenectomy and extended lymphadenectomy are still controversial issues in surgical oncology. The detection methods for metastatic lymph nodes include lymphoscintigraphy and radiolabelled antibody, but immunohistochemical sentinel lymph node (SLN) identification is commonly used. The potential diagnostic use of cell and tissue autofluorescence (AF) is well known. Here we review our studies on the application of AF-based techniques for diagnosing metastatic lymph nodes. We had previously demonstrated that AF imaging allows discrimination between hyperplastic and primary neoplastic lymph nodes. Our more recent studies show that the combination of autofluorescence microspectroscopy and multispectral imaging autofluorescence microscopy can be applied to the diagnosis of secondary neoplastic lymph nodes in gastric and colorectal cancer. These techniques have been validated by histochemical and immunohistochemical methods. Studies are in progress to select the best dye tracer for SLN identification, to improve image quality and to develop a software for automatic analysis of tissue AF to help the decision-making process during surgery.

Colonic and gastric cancer metastatic lymph nodes: applications of autofluorescence-based techniques

Lymphadenectomy and extended lymphadenectomy are still controversial issues in surgical oncology. The detection methods for metastatic lymph nodes include lymphoscintigraphy and radiolabelled antibody, but immunohistochemical sentinel lymph node (SLN) identification is commonly used. The potential diagnostic use of cell and tissue autofluorescence (AF) is well known. Here we review our studies on the application of AF-based techniques for diagnosing metastatic lymph nodes. We had previously demonstrated that AF imaging allows discrimination between hyperplastic and primary neoplastic lymph nodes. Our more recent studies show that the combination of autofluorescence microspectroscopy and multispectral imaging autofluorescence microscopy can be applied to the diagnosis of secondary neoplastic lymph nodes in gastric and colorectal cancer. These techniques have been validated by histochemical and immunohistochemical methods. Studies are in progress to select the best dye tracer for SLN identification, to improve image quality and to develop a software for automatic analysis of tissue AF to help the decision-making process during surgery.

Hypergravity effects on myoblast proliferation and differentiation

This study aimed at the investigation of behavior of myoblasts in conditions of altered gravity. C2C12 cells underwent stimulations by different hypergravity intensities (2 h at 5 g, 10 g, and 20 g) in the Large Diameter Centrifuge of the European Space Agency (ESA), highlighting positive effects on both proliferation and differentiation.

Differentiating effects of the glucagon-like peptide-1 analogue exendin-4 in a human neuronal cell model

Glucagon-like peptide-1 (GLP-1) is an insulinotropic peptide with neurotrophic properties, as assessed in animal cell models. Exendin-4, a GLP-1 analogue, has been recently approved for the treatment of type 2 diabetes mellitus. The aim of this study was to morphologically, structurally, and functionally characterize the differentiating actions of exendin-4 using a human neuronal cell model (i.e., SH-SY5Y cells). We found that exendin-4 increased the number of neurites paralleled by dramatic changes in intracellular actin and tubulin distribution. Electrophysiological analyses showed an increase in cell membrane surface and in stretch-activated-channels sensitivity, an increased conductance of Na(+) channels and amplitude of Ca(++) currents (T- and L-type), typical of a more mature neuronal phenotype. To our knowledge, this is the first demonstration that exendin-4 promotes neuronal differentiation in human cells. Noteworthy, our data support the claimed favorable role of exendin-4 against diabetic neuropathy as well as against different neurodegenerative diseases.

Modeled gravitational unloading triggers differentiation and apoptosis in preosteoclastic cells

Gravity acts permanently on organisms as either static or dynamic stimulation. Understanding the influence of gravitational and mechanical stimuli on biological systems is an intriguing scientific problem. More than two decades of life science studies in low g, either real or modeled by clinostats, as well as experimentation with devices simulating different types of controlled mechanical stimuli, have shown that important biological functions are altered at the single cell level. Here, we show that the human leukemic line FLG 29.1, characterized as an osteoclastic precursor model, is directly sensitive to gravitational unloading, modeled by a random positioning machine (RPM). The phenotypic expression of cytoskeletal proteins, osteoclastic markers, and factors regulating apoptosis was investigated using histochemical and immunohistochemical methods, while the expression of the corresponding genes was analyzed using RT-PCR. A quantitative bone resorption assay was performed. Autofluorescence spectroscopy and imaging were applied to gain information on cell metabolism. The results show that modeled hypogravity may trigger both differentiation and apoptosis in FLG 29.1 cells. Indeed, when comparing RPM versus 1 x g cultures, in the former we found cytoskeletal alterations and a marked increase in apoptosis, but the surviving cells showed an osteoclastic-like morphology, overexpression of osteoclastic markers and the ability to resorb bone. In particular, the overexpression of both RANK and its ligand RANKL, maintained even after return to 1 x g conditions, is consistent with the firing of a differentiation process via a paracrine/autocrine mechanism.

Fibroblast autofluorescence in connective tissue disorders: a future tool for clinical and differential diagnosis?

Marfan syndrome (MFS) is an inherited disorder of connective tissue due to mutations in FBN1 (90%) and TGFBR1 and TGFBR2 (5 to 10%) genes. Clinical and differential diagnosis is difficult because of the inter- and intrafamiliar marked heterogeneity and the variable onset age of clinical manifestations. Among the disorders, in differential diagnosis, thoracic aortic aneurysm (TAA) and Ullrich scleroatonic muscular dystrophy (UCMD) are reported. We evaluate the possibility of utilizing autofluorescence (AF) analysis as a diagnostic tool in the clinical and/or differential diagnosis of MFS and related disorders and in the investigation of the molecular mechanisms involved. Both multispectral imaging autofluorescence microscopy (MIAM) and autofluorescence microspectroscopy (AMS) have been used to characterize AF emission of fibroblasts from patients affected by inherited connective tissue disorders. Our preliminary results show significant differences in AF emission between normal and pathological fibroblasts, suggesting possible improvement in diagnostics of connective tissue disorders by AF analysis.

Multispectral imaging autofluorescence microscopy in colonic and gastric cancer metastatic lymph nodes

BACKGROUND & AIMS

The lymphadenectomy and extended lymphadenectomy procedures have been points of controversy in surgical oncology. The methods available for the detection of metastatic lymph nodes are numerous. These include lymphoscintigraphy and radiolabeled antibody detection, but in most cancers the currently used technique is sentinel lymph node identification, performed primarily through the use of immunohistochemistry. We propose the application of autofluorescence (AF)-based techniques for lymph node evaluation in colorectal and gastric tumors.

METHODS

We studied 30 clinical cases: 15 colorectal cancers and 15 gastric cancers. All of the patients were in the advanced stages of the disease and were candidates for adjuvant therapy. Autofluorescence microspectroscopy and multispectral imaging autofluorescence microscopy have been used to analyze the AF emission of metastatic lymph node sections, excited with 365-nm wavelength radiation. The AF spectra were recorded in the range of 400-700 nm. Monochrome AF images were acquired sequentially through interference filters peaked at 450, 550, and 650 nm, and then combined together in a single red-green-blue image. The AF pattern and the emission spectrum of metastatic lymph nodes have unique characteristics that can be used to distinguish them from the normal ones.

RESULTS

The results, compared with standard histopathologic procedures and with specific staining methods, supplied a satisfactory validation of the proposed technique, revealing the possibility of improving the actual diagnostic procedures for malignant lymph node alterations.

CONCLUSIONS

With the development of appropriate instrumentation, the proposed technique could be particularly suitable in intrasurgical diagnosis of metastatic lymph nodes.

AcrySof Natural intraocular lens optical characteristics during and after different doses of ultraviolet-visible light illumination

PURPOSE

To determine the optical transmission properties of a recently introduced intraocular lens (IOL) (AcrySof Natural SN60AT, Alcon Laboratories) and compare them with those of a conventional IOL (AcrySof SA60AT, Alcon Laboratories) after ultraviolet (UV)-visible light irradiation.

SETTING

Eye Clinic and Department of Clinical Physiopathology, University of Florence, and the National Institute of Applied Optics, Florence, Italy.

METHODS

Two IOLs, the AcrySof Natural with a UV and blue-light filter and the AcrySof without a blue-light filter, were studied. Three IOLs of each model with different dioptric powers were examined in two experimental setups. The samples were stressed with very high irradiance to reproduce light aging, and the transmission properties of the IOLs were studied.

RESULTS

No significant decrease in transmission was found at a UV-visible light dose equivalent to 100 years of light aging.

CONCLUSION

The AcrySof Natural IOL has stable optical characteristics.

Simulated hypogravity impairs the angiogenic response of endothelium by up-regulating apoptotic signals

Health hazards in astronauts are represented by cardiovascular problems and impaired bone healing. These disturbances are characterized by a common event, the loss of function by vascular endothelium, leading to impaired angiogenesis. We investigated whether the exposure of cultured endothelial cells to hypogravity condition could affect their behaviour in terms of functional activity, biochemical responses, morphology, and gene expression. Simulated hypogravity conditions for 72 h produced a reduction of cell number. Genomic analysis of endothelial cells exposed to hypogravity revealed that proapoptotic signals increased, while antiapoptotic and proliferation/survival genes were down-regulated by modelled low gravity. Activation of apoptosis was accompanied by morphological changes with mitochondrial disassembly and organelles/cytoplasmic NAD(P)H redistribution, as evidenced by autofluorescence analysis. In this condition cells were not able to respond to angiogenic stimuli in terms of migration and proliferation. Our study documents functional, morphological, and transcription alterations in vascular endothelium exposed to simulated low gravity conditions, thus providing insights on the occurrence of vascular tissue dysregulation in crewmen during prolonged space flights. Moreover, the alteration of vascular endothelium can intervene as a concause in other systemic effects, like bone remodelling, observed in weightlessness.

Cell and tissue autofluorescence research and diagnostic applications

Cells contain molecules, which become fluorescent when excited by UV/Vis radiation of suitable wavelength. This fluorescence emission, arising from endogenous fluorophores, is an intrinsic property of cells and is called auto-fluorescence to be distinguished from fluorescent signals obtained by adding exogenous markers. The majority of cell auto-fluorescence originates from mitochondria and lysosomes. Together with aromatic amino acids and lipo-pigments, the most important endogenous fluorophores are pyridinic (NADPH) and flavin coenzymes. In tissues, the extracellular matrix often contributes to the auto-fluorescence emission more than the cellular component, because collagen and elastin have, among the endogenous fluorophores, a relatively high quantum yield. Changes occurring in the cell and tissue state during physiological and/or pathological processes result in modifications of the amount and distribution of endogenous fluorophores and chemical-physical properties of their microenvironment. Therefore, analytical techniques based on auto-fluorescence monitoring can be utilized in order to obtain information about morphological and physiological state of cells and tissues. Moreover, auto-fluorescence analysis can be performed in real time because it does not require any treatment of fixing or staining of the specimens. In the past few years spectroscopic and imaging techniques have been developed for many different applications both in basic research and diagnostics.

Dependence of leukemic cell autofluorescence patterns on the degree of differentiation

The characterisation of leukemic cell autofluorescence during differentiation, induced by 12-O-tetradecanoylphorbol 13-acetate and all-trans retinoic acid, was performed by autofluorescence microspectroscopy and multispectral imaging autofluorescence microscopy. We have found that a dependence exists between the cell autofluorescence pattern and the degree of cell differentiation. When cells differentiate, their autofluorescence emission changes, following the morphological and functional rearrangement of cell structures. A decrease in emission intensity and a different distribution of endogenous fluorophores are observed. Thus, autofluorescence monitoring on living cells is a potentially useful tool for in vitro study of the differentiation processes. Furthermore, different maturation steps can be distinguished on the basis of the cell fluorescence pattern, leading the way to future application of the technique in diagnostics.