Low Dose Radiation Therapy Induces Long-Lasting Reduction of Pain and Immune Modulations in the Peripheral Blood - Interim Analysis of the IMMO-LDRT01 Trial

Non-homogenous intratumor ionizing radiation doses synergize with PD1 and CXCR2 blockade

The efficacy and side effects of radiotherapy (RT) depend on parameters like dose and the volume of irradiated tissue. RT induces modulations of the tumor immune microenvironment (TIME) that are dependent on the dose. Low dose RT (LDRT, i.e., single doses of 0.5-2 Gy) has been shown to promote immune infiltration into the tumor. Here we hypothesize that partial tumor irradiation combining the immunostimulatory/non-lethal properties of LDRT with cell killing/shrinkage properties of high dose RT (HDRT) within the same tumor mass could enhance anti-tumor responses when combined with immunomodulators. In models of colorectal and breast cancer in immunocompetent female mice, partial irradiation (PI) with millimetric precision to deliver LDRT (2 Gy) and HDRT (16 Gy) within the same tumor induces substantial tumor control when combined with anti-PD1. Using flow cytometry, cytokine profiling and single-cell RNA sequencing, we identify a crosstalk between the TIME of the differentially irradiated tumor volumes. PI reshapes tumor-infiltrating CD8+ T cells into more cytotoxic and interferon-activated phenotypes but also increases the infiltration of pro-tumor neutrophils driven by CXCR2. The combination of the CXCR2 antagonist SB225002 with PD1 blockade and PI improves tumor control and mouse survival. Our results suggest a strategy to reduce RT toxicity and improve the therapeutic index of RT and immune checkpoint combinations.

Heat therapy in rheumatic and musculoskeletal diseases - an overview of clinical and molecular effects

Rheumatic and musculoskeletal diseases (RMDs) usually lead to morphological and functional deficits of various extend, increased morbidity and a considerable loss of quality of life. Modern pharmacological treatment has become effective and can stop disease progression. Nonetheless, disease progression is often only slowed down. Moreover, pharmacological treatment does not improve functionality per se. Therefore, multimodal treatment of rheumatic disorders with physical therapy being a key element is of central importance for best outcomes. In recent years, research into physical medicine shifted from a sole investigation of its clinical effects to a combined investigation of clinical effects and potential changes in the molecular level (e.g., inflammatory cytokines and the cellular autoimmune system), thus offering new explanations of clinical effects of physical therapy. In this review we provide an overview of studies investigating different heat applications in RMDs, their effect on disease activity, pain and their influence on the molecular level.

Effects of serial radon spa therapy on pain and peripheral immune status in patients suffering from musculoskeletal disorders- results from a prospective, randomized, placebo-controlled trial

In this randomized, placebo-controlled cross-over trial we aimed to investigate if radon spa therapy exerts more pain relief than exposure to warm water alone. In addition, immunological parameters were assessed in both treatment groups. In the RAD-ON02 trial, 116 patients suffering from musculoskeletal disorders (MSDs) received either serial radon spa or solely warm water baths. Pain intensity was assessed by determination of different pain parameters on a visual analogue scale and by pressure point dolorimetry at baseline and at weeks 4, 12 and 24. The longitudinal immune status of the patients was analyzed by a flow cytometry-based assay from peripheral blood at the time points of pain assessments. There were no side effects attributable to radon exposure observed. However, radon spa was superior to warm water applications at week 4 in terms of pain reduction. Pain and morning stiffness at the time of assessment were significantly reduced after radon spa (p<0.001, p<0.01) but not after warm water baths. The dolorimetry resulted in a significantly higher exerted pressure strength in patients after radon spa (p<0.001), but not after warm water applications. During the long-term follow-up, both treatment modalities reduced pain to a similar degree and pain modulation was not distorted by the participants' intake of analgesics. No significant changes in the immune status attributable specifically to radon were found, even though the increase in regulatory T cell counts occurs earlier after radon baths than after sole warm water baths and a higher level of significance is reached after radon spa at week 24. Serial radon spa has additive pain-relieving effects. The immunological parameters assessed in our study appear not to be directly linked to the pain reduction caused by radon exposure, at least in MSD patients with predominantly degenerative diseases.

Clinical trial registration

https://www.clinicaltrialsregister.eu/ctr-search/search?query=rad-on02, identifier 2016-002085-31; https://drks.de/search/de/trial, identifier DRKS00016019.

Osteo-immunological impact of radon spa treatment: due to radon or spa alone? Results from the prospective, thermal bath placebo-controlled RAD-ON02 trial

Musculoskeletal disorders (MSDs) are associated with pain and lead to reduced mobility and quality of life for patients. Radon therapy is used as alternative or complementary to pharmaceutical treatments. According to previous reports, radon spa leads to analgesic and anti-inflammatory effects, but the cellular and molecular mechanisms are widely unknown. A previous study (RAD-ON01) revealed, that bone erosion markers like collagen fragments (C-terminal telopeptide, CTX) are reduced after radon spa treatment in serum of patients with degenerative MSDs. Within the scope of the prospective, placebo-controlled RAD-ON02 trial presented here, we analyzed the influence of radon and thermal spa treatment on osteoclastogenesis. From patient blood, we isolate monocytes, seeded them on bone slices and differentiated them in the presence of growth factors into mature osteoclasts (mOCs). Subsequent analysis showed a smaller fraction of mOCs after both treatments, which was even smaller after radon spa treatment. A significantly reduced resorbed area on bone slices reflects this result. Only after radon spa treatment, we detected in the serum of patients a significant decrease of receptor activator of NF-κB ligand (RANKL), which indicates reduced differentiation of OCs. However, other markers for bone resorption (CTX) and bone formation (OPG, OCN) were not altered after both treatments. Adipokines, such as visfatin and leptin that play a role in some MSD-types by affecting osteoclastogenesis, were not changed after both treatments. Further, also immune cells have an influence on osteoclastogenesis, by inhibiting and promoting terminal differentiation and activation of OCs, respectively. After radon treatment, the fraction of Treg cells was significantly increased, whereas Th17 cells were not altered. Overall, we observed that both treatments had an influence on osteoclastogenesis and bone resorption. Moreover, radon spa treatment affected the Treg cell population as well as the Th17/Treg ratio were affected, pointing toward a contribution of the immune system after radon spa. These data obtained from patients enrolled in the RAD-ON02 trial indicate that radon is not alone responsible for the effects on bone metabolism, even though they are more pronounced after radon compared to thermal spa treatment.

Low-dose radiotherapy of osteoarthritis: from biological findings to clinical effects-challenges for future studies

Osteoarthritis (OA) is one of the most common and socioeconomically relevant diseases, with rising incidence and prevalence especially with regard to an ageing population in the Western world. Over the decades, the scientific perception of OA has shifted from a simple degeneration of cartilage and bone to a multifactorial disease involving various cell types and immunomodulatory factors. Despite a wide range of conventional treatment modalities available, a significant proportion of patients remain treatment refractory. Low-dose radiotherapy (LDRT) has been used for decades in the treatment of patients with inflammatory and/or degenerative diseases and has proven a viable option even in cohorts of patients with a rather poor prognosis. While its justification mainly derives from a vast body of empirical evidence, prospective randomized trials have until now failed to prove the effectiveness of LDRT. Nevertheless, over the decades, adaptions of LDRT treatment modalities have evolved using lower dosages with establishment of different treatment schedules for which definitive clinical proof is still pending. Preclinical research has revealed that the immune system is modulated by LDRT and very recently osteoimmunological mechanisms have been described. Future studies and investigations further elucidating the underlying mechanisms are an essential key to clarify the optimal patient stratification and treatment procedure, considering the patients' inflammatory status, age, and sex. The present review aims not only to present clinical and preclinical knowledge about the mechanistic and beneficial effects of LDRT, but also to emphasize topics that will need to be addressed in future studies. Further, a concise overview of the current status of the underlying radiobiological knowledge of LDRT for clinicians is given, while seeking to stimulate further translational research.

Concerted regulation of OPG/RANKL/ NF‑κB/MMP-13 trajectories contribute to ameliorative capability of prodigiosin and/or low dose γ-radiation against adjuvant- induced arthritis in rats

BACKGROUND

Prodigiosin (PDG) is a microbial red dye with antioxidant and anti-inflammatory properties, although its effect on rheumatoid arthritis (RA) remains uncertain. Also, multiple doses of low dose γ- radiation (LDR) have been observed to be as a successful intervention for RA. Thus, the purpose of this study was to investigate the ameliorative potential of PDG and/or LDR on adjuvant-induced arthritis (AIA) in rats.

METHODS

The anti-inflammatory and anti-arthritic effects of PDG and/or LDR were examined in vitro and in vivo, respectively. In the AIA model, the arthritic indexes, paw swelling degrees, body weight gain, and histopathological assessment in AIA rats were assayed. The impact of PDG (200 µg/kg; p.o) and/or LDR (0.5 Gy) on the levels of pro- and anti-inflammatory cytokines (IL-1β, TNF-α, IL-6, IL-18, IL-17A, and IL-10) as well as the regulation of osteoprotegrin (OPG)/ receptor activator of nuclear factor κB ligand (RANKL)/ nuclear factor-κB (NF-κB)/MMP-13 pathways was determined. Methotrexate (MTX; 0.05 mg/kg; twice/week, i.p) was administered concurrently as a standard anti-arthritic drug.

RESULTS

PDG and/or LDR markedly diminished the arthritic indexes, paw edema, weigh loss in AIA rats, alleviated the pathological alterations in joints, reduced the levels of pro-inflammatory cytokines IL-1β, TNF-α, IL-6, IL-18, IL-17A, and RANKL in serum and synovial tissues, while increasing anti-inflammatory cytokines IL-10 and OPG levels. Moreover, PDG and/or LDR down-regulated the expression of RANKL, NF-κBp65, MMP13, caspase-3, and decreased the RANKL/OPG ratio, whereas OPG and collagen II were enhanced in synovial tissues.

CONCLUSION

PDG and/or LDR exhibited obvious anti-RA activity on AIA.

B Lymphocytes in Alzheimer's Disease-A Comprehensive Review

Alzheimer's disease (AD) represents the most common type of neurodegenerative dementia and is characterized by extracellular amyloid-β (Aβ) deposition, pathologic intracellular tau protein tangles, and neuronal loss. Increasing evidence has been accumulating over the past years, supporting a pivotal role of inflammation in the pathogenesis of AD. Microglia, monocytes, astrocytes, and neurons have been shown to play a major role in AD-associated inflammation. However recent studies showed that the role of both T and B lymphocytes may be important. In particular, B lymphocytes are the cornerstone of humoral immunity, they constitute a heterogenous population of immune cells, being their mature subsets significantly impacted by the inflammatory milieu. The role of B lymphocytes on AD pathogenesis is gaining interest for several reasons. Indeed, the majority of elderly people develop the process of "inflammaging", which is characterized by increased blood levels of proinflammatory molecules associated with an elevated susceptibility to chronic diseases. Epitope-specific alteration pattern of naturally occurring antibodies targeting the amino-terminus and the mid-domain of Aβ in both plasma and cerebrospinal fluid has been described in AD patients. Moreover, a possible therapeutic role of B lymphocytes depletion was recently demonstrated in murine AD models. Interestingly, active immunization against Aβ and tau, one of the main therapeutic strategies under investigation, depend on B lymphocytes. Finally. several molecules being tested in AD clinical trials can modify the homeostasis of B cells. This review summarizes the evidence supporting the role of B lymphocytes in AD from the pathogenesis to the possible therapeutic implications.

Modulation of Differentiation and Bone Resorbing Activity of Human (Pre-) Osteoclasts After X-Ray Exposure

Low-dose radiotherapy (LD-RT) is a local treatment option for patients with chronic degenerative and inflammatory diseases, in particular musculoskeletal diseases. Despite reported analgesic and anti-inflammatory effects, cellular and molecular mechanisms related to osteoimmunological effects are still elusive. Here we test the hypothesis that X-irradiation inhibits the differentiation of precursor osteoclasts into mature osteoclasts (mOC) and their bone resorbing activity. Circulating monocytes from healthy donors were isolated and irradiated after attachment with single or fractionated X-ray doses, comparable to an LD-RT treatment scheme. Then monocytes underwent ex vivo differentiation into OC during cultivation up to 21 days, under conditions mimicking the physiological microenvironment of OC on bone. After irradiation, apoptotic frequencies were low, but the total number of OC precursors and mOC decreased up to the end of the cultivation period. On top, we observed an impairment of terminal differentiation, i.e. a smaller fraction of mOC, reduced resorbing activity on bone, and release of collagen fragments. We further analyzed the effect of X-irradiation on multinucleation, resulting from the fusion of precursor OC, which occurs late during OC differentiation. At 21 days after exposure, the observation of smaller cellular areas and a reduced number of nuclei per mOC suggest an impaired fusion of OC precursors to form mOC. Before, at 14 days, the nuclear translocation of Nuclear Factor Of Activated T Cells 1 (NFATc1), a master regulator of osteoclast differentiation and fusion, was decreased. In first results, obtained in the frame of a longitudinal LD-RT study, we previously reported a pain-relieving effect in patients. However, in a subgroup of patients suffering from Calcaneodynia or Achillodynia, we did not observe a consistent decrease of established blood markers for resorption and formation of bone, or modified T cell subtypes involved in regulating these processes. To assess the relevance of changes in bone metabolism for other diseases treated with LD-RT will be subject of further studies. Taken together, we observed that in vitro X-irradiation of monocytes results in an inhibition of the differentiation into bone-resorbing OC and a concomitant reduction of resorbing activity. The detected reduced NFATc1 signaling could be one underlying mechanism.