Phospholipase Cgamma1 (PLCgamma1) is an important signaling effector of T cell receptor (TCR). To investigate the role of PLCgamma1 in T cell biology, we generated and examined mice with T cell-specific deletion of PLCgamma1. We demonstrate that PLCgamma1 deficiency affects positive and negative selection, significantly reduces single-positive thymocytes and peripheral T cells, and impairs TCR-induced proliferation and cytokine production, and the activation of ERK, JNK, AP-1, NFAT, and NF-kappaB. Importantly, PLCgamma1 deficiency impairs the development and function of FoxP3(+) regulatory T cells, causing inflammatory/autoimmune symptoms. Therefore, PLCgamma1 is essential for T cell development, activation, and tolerance.

Heart transplantation is a well-established therapy for end-stage heart failure in children and young adults. The highest risk of graft loss occurs in the first 60 days post-transplant. Donor fraction of cell-free DNA is a highly sensitive marker of graft injury. Changes in cell-free DNA levels have not previously been studied in depth in patients early after heart transplant. A prospective study was conducted among heart transplant recipients at a single pediatric heart center. Blood samples were collected from children and young adult transplant patients at three time points within 10 days of transplantation. DF and total cell-free DNA levels were measured using a targeted method (myTAIHEART ). In 17 patients with serial post-transplant samples, DF peaks in the first 2 days after transplant (3.5%, [1.9-10]%) and then declines toward baseline (0.27%, [0.19-0.52]%) by 6-9 days. There were 4 deaths in the first year among the 10 patients with complete sample sets, and 3 out of 4 who died had a late rise or blunted decline in donor fraction. Patients who died trended toward an elevated total cell-free DNA at 1 week (41.5, [34-65] vs 13.6, [6.2-22] P = .07). Donor fraction peaks early after heart transplant and then declines toward baseline. Patients without sustained decline in donor fraction and/or elevated total cell-free DNA at 1 week may have worse outcomes.

Lifelong noninvasive rejection monitoring in heart transplant patients is a critical clinical need historically poorly met in adults and unavailable for children and infants. Cell-free DNA (cfDNA) donor-specific fraction (DF), a direct marker of selective donor organ injury, is a promising analytical target. Methodological differences in sample processing and DF determination profoundly affect quality and sensitivity of cfDNA analyses, requiring specialized optimization for low cfDNA levels typical of transplant patients. Using next-generation sequencing, we previously correlated elevated DF with acute cellular and antibody-mediated rejection (ACR and AMR) in pediatric and adult heart transplant patients. However, next-generation sequencing is limited by cost, TAT, and sensitivity, leading us to clinically validate a rapid, highly sensitive, quantitative genotyping test, myTAIHEART®, addressing these limitations. To assure pre-analytical quality and consider interrelated cfDNA measures, plasma preparation was optimized and total cfDNA (TCF) concentration, DNA fragmentation, and DF quantification were validated in parallel for integration into myTAIHEART reporting. Analytical validations employed individual and reconstructed mixtures of human blood-derived genomic DNA (gDNA), cfDNA, and gDNA sheared to apoptotic length. Precision, linearity, and limits of blank/detection/quantification were established for TCF concentration, DNA fragmentation ratio, and DF determinations. For DF, multiplexed high-fidelity amplification followed by quantitative genotyping of 94 SNP targets was applied to 1168 samples to evaluate donor options in staged simulations, demonstrating DF call equivalency with/without donor genotype. Clinical validation studies using 158 matched endomyocardial biopsy-plasma pairs from 76 pediatric and adult heart transplant recipients selected a DF cutoff (0.32%) producing 100% NPV for ≥2R ACR. This supports the assay's conservative intended use of stratifying low versus increased probability of ≥2R ACR. myTAIHEART is clinically validated for heart transplant recipients ≥2 months old and ≥8 days post-transplant, expanding opportunity for noninvasive transplant rejection assessment to infants and children and to all recipients >1 week post-transplant.

The role of an adverse maternal environment (AME) in conjunction with a postweaning Western diet (WD) in the development of nonalcoholic fatty liver disease (NAFLD) in adult offspring has not been explored. Likewise, the molecular mechanisms associated with AME-induced NAFLD have not been studied. The fatty acid translocase or cluster of differentiation 36 (CD36) has been implicated to play a causal role in the pathogenesis of WD-induced steatosis. However, it is unknown if CD36 plays a role in AME-induced NAFLD.

Heart disease is a significant adverse event caused by radiotherapy for some cancers. Identifying the origins of radiogenic heart disease will allow therapies to be developed. Previous studies showed non-targeted effects manifest as fibrosis in the non-irradiated heart after 120 days following targeted X-irradiation of the kidneys with 10 Gy in WAG/RijCmcr rats. To demonstrate the involvement of T cells in driving pathophysiological responses in the out-of-field heart, and to characterize the timing of immune cell engagement, we created and validated a T cell knock downrat on the WAG genetic backgrou nd. Irradiation of the kidneys with 10 Gy of X-rays in wild-type rats resulted in infiltration of T cells, natural killer cells, and macrophages after 120 days, and none of these after 40 days, suggesting immune cell engagement is a late response. The radiation nephropathy and cardiac fibrosis that resulted in these animals after 120 days was significantly decreased in irradiated T cell depleted rats. We conclude that T cells function as an effector cell in communicating signals from the irradiated kidneys which cause pathologic remodeling of non-targeted heart.

Vaccinations are widely credited with reducing death rates from COVID-19, but the underlying host-viral mechanisms/interactions for morbidity and mortality of SARS-CoV-2 infection remain poorly understood. Acute respiratory distress syndrome (ARDS) describes the severe lung injury, which is pathologically associated with alveolar damage, inflammation, non-cardiogenic edema, and hyaline membrane formation. Because proteostatic pathways play central roles in cellular protection, immune modulation, protein degradation, and tissue repair, we examined the pathological features for the unfolded protein response (UPR) using the surrogate biomarker glucose-regulated protein 78 (GRP78) and co-receptor for SARS-CoV-2. At autopsy, immunostaining of COVID-19 lungs showed highly elevated expression of GRP78 in both pneumocytes and macrophages compared with that of non-COVID control lungs. GRP78 expression was detected in both SARS-CoV-2-infected and un-infected pneumocytes as determined by multiplexed immunostaining for nucleocapsid protein. In macrophages, immunohistochemical staining for GRP78 from deceased COVID-19 patients was increased but overlapped with GRP78 expression taken from surgical resections of non-COVID-19 controls. In contrast, the robust in situ GRP78 immunostaining of pneumocytes from COVID-19 autopsies exhibited no overlap and was independent of age, race/ethnicity, and gender compared with that from non-COVID-19 controls. Our findings bring new insights for stress-response pathways involving the proteostatic network implicated for host resilience and suggest that targeting of GRP78 expression with existing therapeutics might afford an alternative therapeutic strategy to modulate host-viral interactions during SARS-CoV-2 infections.

The radiation environment astronauts are exposed to in deep space includes galactic cosmic radiation (GCR) with different proportions of all naturally occurring ions. To assist NASA with assessment of risk to the brain following exposure to a mixture of ions broadly representative of the GCR, we assessed the behavioral and cognitive performance of female and male C57BL/6J × DBA2/J F1 (B6D2F1) mice two months following rapidly delivered, sequential 6 beam irradiation with protons (1 GeV, LET = 0.24 keV, 50%), 4He ions (250 MeV/n, LET = 1.6 keV/μm, 20%), 16O ions (250 MeV/n, LET = 25 keV/μm 7.5%), 28Si ions (263 MeV/n, LET = 78 keV/μm, 7.5%), 48Ti ions (1 GeV/n, LET = 107 keV/μm, 7.5%), and 56Fe ions (1 GeV/n, LET = 151 keV/μm, 7.5%) at 0, 25, 50, or 200 cGy) at 4-6 months of age. When the activity over 3 days of open field habituation was analyzed in female mice, those irradiated with 50 cGy moved less and spent less time in the center than sham-irradiated mice. Sham-irradiated female mice and those irradiated with 25 cGy showed object recognition. However, female mice exposed to 50 or 200 cGy did not show object recognition. When fear memory was assessed in passive avoidance tests, sham-irradiated mice and mice irradiated with 25 cGy showed memory retention while mice exposed to 50 or 200 cGy did not. The effects of radiation passive avoidance memory retention were not sex-dependent. There was no effect of radiation on depressive-like behavior in the forced swim test. There was a trend toward an effect of radiation on BDNF levels in the cortex of males, but not for females, with higher levels in male mice irradiated with 50 cGy than sham-irradiated. Finally, sequential 6-ion irradiation impacted the composition of the gut microbiome in a sex-dependent fashion. Taxa were uncovered whose relative abundance in the gut was associated with the radiation dose received. Thus, exposure to sequential six-beam irradiation significantly affects behavioral and cognitive performance and the gut microbiome.

Infantile hemangioma is a vascular tumor characterized by the rapid growth of disorganized blood vessels followed by slow spontaneous involution. The underlying molecular mechanisms that regulate hemangioma proliferation and involution still are not well elucidated. Our previous studies reported that NOGOB receptor (NGBR), a transmembrane protein, is required for the translocation of prenylated RAS from the cytosol to the plasma membrane and promotes RAS activation. Here, we show that NGBR was highly expressed in the proliferating phase of infantile hemangioma, but its expression decreased in the involuting phase, suggesting that NGBR may have been involved in regulating the growth of proliferating hemangioma. Moreover, we demonstrate that NGBR knockdown in hemangioma stem cells (HemSCs) attenuated growth factor-stimulated RAS activation and diminished the migration and proliferation of HemSCs, which is consistent with the effects of RAS knockdown in HemSCs. In vivo differentiation assay further shows that NGBR knockdown inhibited blood vessel formation and adipocyte differentiation of HemSCs in immunodeficient mice. Our data suggest that NGBR served as a RAS modulator in controlling the growth and differentiation of HemSCs.

Selective inhibitors of sodium-glucose cotransporter 2 (SGLT2)-mediated reabsorption of glucose in the proximal tubule of the kidney are being developed for the treatment of diabetes. SGLT2 shares high degree of homology with SGLT3; however, very little is known about the expression and functional role of SGLT3 in the human kidney. Indeed, the SGLT2 inhibitors that are currently in clinical trials might affect the expression and/or the activity of SGLT3. Therefore, the present study examined the expression of SGLT3 mRNA and protein in human kidney and in a human proximal tubule HK-2 cell line. The results indicated that human SGLT3 (hSGLT3) message and protein are expressed both in vivo and in vitro. We also studied the activity of hSGLT3 protein following its over-expression in mammalian kidney-derived COS-7 cells and in HK-2 cells treated with the imino sugar deoxynojirimycin (DNJ), a potent agonist of hSGLT3. Over-expression of hSGLT3 in COS-7 cells increased intracellular sodium concentration by 3-fold without affecting glucose transport. Activation of hSGLT3 with DNJ (50μM) increased sodium uptake in HK-2 cells by 5.5 fold and this effect could be completely blocked with SGLT inhibitor phlorizin (50μM). These results suggest that SGLT3 is expressed in human proximal tubular cells where it serves as a novel sodium transporter. Up-regulation of the expression of SGLT3 in the proximal tubule in diabetic patients may contribute to the elevated sodium transport in this segment of the nephron that has been postulated to promote hyperfiltration and renal injury.

The space radiation environment includes helium (⁴He) ions that may impact brain function. As little is known about the effects of exposures to ⁴He ions on the brain, we assessed the behavioral and cognitive performance of C57BL/6J × DBA2/J F1 (B6D2F1) mice three months following irradiation with ⁴He ions (250 MeV/n; linear energy transfer (LET) = 1.6 keV/μm; 0, 21, 42 or 168 cGy). Sham-irradiated mice and mice irradiated with 21 or 168 cGy showed novel object recognition, but mice irradiated with 42 cGy did not. In the passive avoidance test, mice received a slight foot shock in a dark compartment, and latency to re-enter that compartment was assessed 24 h later. Sham-irradiated mice and mice irradiated with 21 or 42 cGy showed a higher latency on Day 2 than Day 1, but the latency to enter the dark compartment in mice irradiated with 168 cGy was comparable on both days. ⁴He ion irradiation, at 42 and 168 cGy, reduced the levels of the dendritic marker microtubule-associated protein-2 (MAP-2) in the cortex. There was an effect of radiation on apolipoprotein E (apoE) levels in the hippocampus and cortex, with higher apoE levels in mice irradiated at 42 cGy than 168 cGy and a trend towards higher apoE levels in mice irradiated at 21 than 168 cGy. In addition, in the hippocampus, there was a trend towards a negative correlation between MAP-2 and apoE levels. While reduced levels of MAP-2 in the cortex might have contributed to the altered performance in the passive avoidance test, it does not seem sufficient to do so. The higher hippocampal and cortical apoE levels in mice irradiated at 42 than 168 cGy might have served as a compensatory protective response preserving their passive avoidance memory. Thus, there were no alterations in behavioral performance in the open filed or depressive-like behavior in the forced swim test, while cognitive impairments were seen in the object recognition and passive avoidance tests, but not in the contextual or cued fear conditioning tests. Taken together, the results indicate that some aspects of cognitive performance are altered in male mice exposed to ⁴He ions, but that the response is task-dependent. Furthermore, the sensitive doses can vary within each task in a non-linear fashion. This highlights the importance of assessing the cognitive and behavioral effects of charged particle exposure with a variety of assays and at multiple doses, given the possibility that lower doses may be more damaging due to the absence of induced compensatory mechanisms at higher doses.

Exposure to a small number of high-energy heavy charged particles (HZE ions), as found in the deep space environment, could significantly affect astronaut health following prolonged periods of space travel if these ions induce mutations and related cancers. In this study, we used an in vivo mutagenesis assay to define the mutagenic effects of accelerated 56Fe ions (1 GeV/amu, 151 keV/μm) in the mouse kidney epithelium exposed to doses ranging from 0.25 to 2.0 Gy. These doses represent fluences ranging from 1 to 8 particle traversals per cell nucleus. The Aprt locus, located on chromosome 8, was used to select induced and spontaneous mutants. To fully define the mutagenic effects, we used multiple endpoints including mutant frequencies, mutation spectrum for chromosome 8, translocations involving chromosome 8, and mutations affecting non-selected chromosomes. The results demonstrate mutagenic effects that often affect multiple chromosomes for all Fe ion doses tested. For comparison with the most abundant sparsely ionizing particle found in space, we also examined the mutagenic effects of high-energy protons (1 GeV, 0.24 keV/μm) at 0.5 and 1.0 Gy. Similar doses of protons were not as mutagenic as Fe ions for many assays, though genomic effects were detected in Aprt mutants at these doses. Considered as a whole, the data demonstrate that Fe ions are highly mutagenic at the low doses and fluences of relevance to human spaceflight, and that cells with considerable genomic mutations are readily induced by these exposures and persist in the kidney epithelium. The level of genomic change produced by low fluence exposure to heavy ions is reminiscent of the extensive rearrangements seen in tumor genomes suggesting a potential initiation step in radiation carcinogenesis.

Exposure monitoring with personal silicone wristband samplers was demonstrated in Peru in four agriculture and urban communities where logistic and practical constraints hinder use of more traditional approaches. Wristbands and associated methods enabled quantitation of 63 pesticides and screening for 1397 chemicals including environmental contaminants and personal care products. Sixty-eight wristbands were worn for approximately one month by volunteers from four communities of Alto Mayo, Peru. We identified 106 chemicals from eight chemical classes among all wristbands. Agricultural communities were characterized by pesticides and PAHs, while the urban communities had more personal care products present. Multiple linear regressions explained up to 40% of variance in wristbands from chlorpyrifos, cypermethrin, and DDT and its metabolites (DDx) (r2=0.39, 0.30, 0.40, respectively). All three pesticides were significantly different between communities, and cypermethrin and DDx were associated with participant age. The calculated relative age of DDT suggested some communities had more recent exposure than others. This work aids health research in the Alto Mayo and beyond by identifying typical mixtures and potential sources of exposure to organic chemicals in the personal environment. Silicone wristband sampling with chemical screening is a candidate for widespread use in exposure monitoring in remote areas.

The radiation environment in deep space includes the galactic cosmic radiation with different proportions of all naturally occurring ions from protons to uranium. Most experimental animal studies for assessing the biological effects of charged particles have involved acute dose delivery for single ions and/or fractionated exposure protocols. Here, we assessed the behavioral and cognitive performance of female and male C57BL/6J × DBA2/J F1 (B6D2F1) mice 2 months following rapidly delivered, sequential irradiation with protons (1 GeV, 60%), 16O (250 MeV/n, 20%), and 28Si (263 MeV/n, 20%) at 0, 25, 50, or 200 cGy at 4-6 months of age. Cortical BDNF, CD68, and MAP-2 levels were analyzed 3 months after irradiation or sham irradiation. During the dark period, male mice irradiated with 50 cGy showed higher activity levels in the home cage than sham-irradiated mice. Mice irradiated with 50 cGy also showed increased depressive behavior in the forced swim test. When cognitive performance was assessed, sham-irradiated mice of both sexes and mice irradiated with 25 cGy showed normal responses to object recognition and novel object exploration. However, object recognition was impaired in female and male mice irradiated with 50 or 200 cGy. For cortical levels of the neurotrophic factor BDNF and the marker of microglial activation CD68, there were sex × radiation interactions. In females, but not males, there were increased CD68 levels following irradiation. In males, but not females, there were reduced BDNF levels following irradiation. A significant positive correlation between BDNF and CD68 levels was observed, suggesting a role for activated microglia in the alterations in BDNF levels. Finally, sequential beam irradiation impacted the diversity and composition of the gut microbiome. These included dose-dependent impacts and alterations to the relative abundance of several gut genera, such as Butyricicoccus and Lachnospiraceae. Thus, exposure to rapidly delivered sequential proton, 16O ion, and 28Si ion irradiation significantly affects behavioral and cognitive performance, cortical levels of CD68 and BDNF in a sex-dependent fashion, and the gut microbiome.

A limitation of simulated space radiation studies is that radiation exposure is not the only environmental challenge astronauts face during missions. Therefore, we characterized behavioral and cognitive performance of male WAG/Rij rats 3 months after sham-irradiation or total body irradiation with a simplified 5-ion mixed beam exposure in the absence or presence of simulated weightlessness using hindlimb unloading (HU) alone. Six months following behavioral and cognitive testing or 9 months following sham-irradiation or total body irradiation, plasma and brain tissues (hippocampus and cortex) were processed to determine whether the behavioral and cognitive effects were associated with long-term alterations in metabolic pathways in plasma and brain. Sham HU, but not irradiated HU, rats were impaired in spatial habituation learning. Rats irradiated with 1.5 Gy showed increased depressive-like behaviors. This was seen in the absence but not presence of HU. Thus, HU has differential effects in sham-irradiated and irradiated animals and specific behavioral measures are associated with plasma levels of distinct metabolites 6 months later. The combined effects of HU and radiation on metabolic pathways in plasma and brain illustrate the complex interaction of environmental stressors and highlights the importance of assessing these interactions.

Introduction: The space environment astronauts experience during space missions consists of multiple environmental challenges, including microgravity. In this study, we assessed the behavioral and cognitive performances of male Fisher rats 2 months after sham irradiation or total body irradiation with photons in the absence or presence of simulated microgravity. We analyzed the plasma collected 9 months after sham irradiation or total body irradiation for distinct alterations in metabolic pathways and to determine whether changes to metabolic measures were associated with specific behavioral and cognitive measures. Methods: A total of 344 male Fischer rats were irradiated with photons (6 MeV; 3, 8, or 10 Gy) in the absence or presence of simulated weightlessness achieved using hindlimb unloading (HU). To identify potential plasma biomarkers of photon radiation exposure or the HU condition for behavioral or cognitive performance, we performed regression analyses. Results: The behavioral effects of HU on activity levels in an open field, measures of anxiety in an elevated plus maze, and anhedonia in the M&M consumption test were more pronounced than those of photon irradiation. Phenylalanine, tyrosine, and tryptophan metabolism, and phenylalanine metabolism and biosynthesis showed very strong pathway changes, following photon irradiation and HU in animals irradiated with 3 Gy. Here, 29 out of 101 plasma metabolites were associated with 1 out of 13 behavioral measures. In the absence of HU, 22 metabolites were related to behavioral and cognitive measures. In HU animals that were sham-irradiated or irradiated with 8 Gy, one metabolite was related to behavioral and cognitive measures. In HU animals irradiated with 3 Gy, six metabolites were related to behavioral and cognitive measures. Discussion: These data suggest that it will be possible to develop stable plasma biomarkers of behavioral and cognitive performance, following environmental challenges like HU and radiation exposure.

Mortality rates following pediatric cardiac surgery with cardiopulmonary bypass have declined over decades, but have plateaued in recent years. This is in part attributable to persistent issues with postoperative global inflammation and myocardial dysfunction, commonly manifested by systemic inflammatory response syndrome and low cardiac output syndrome, respectively. Quantified cell-free DNA (cfDNA), of nuclear or mitochondrial origin, has emerged as a biomarker for both inflammation and myocardial injury. Recent data suggest that nuclear cfDNA (ncfDNA) may quantify inflammation, whereas mitochondrial cfDNA (mcfDNA) may correlate with the degree of myocardial injury. We hypothesize that threshold levels of ncfDNA and mcfDNA can be established that are sensitive and specific for postoperative mortality mediated through independent pathways, and that association will be enhanced with combined analysis.

The ability of simvastatin to mitigate the increases in risk factors for and the occurrence of cardiac disease after 10 Gy total body irradiation (TBI) was determined. This radiation dose is relevant to conditioning for stem cell transplantation and threats from radiological terrorism. Male rats received single dose TBI of 10 Gy. Age-matched, sham-irradiated rats served as controls. Lipid profile, heart and liver morphology and cardiac mechanical function were determined for up to 120 days after irradiation. TBI resulted in a sustained increase in total- and LDL-cholesterol (low-density lipoprotein-cholesterol), and triglycerides. Simvastatin (10 mg/kg body weight/day) administered continuously from 9 days after irradiation mitigated TBI-induced increases in total- and LDL-cholesterol and triglycerides, as well as liver injury. TBI resulted in cellular peri-arterial fibrosis, whereas control hearts had less collagen and fibrosis. Simvastatin mitigated these morphological injuries. TBI resulted in cardiac mechanical dysfunction. Simvastatin mitigated cardiac mechanical dysfunction 20-120 days following TBI. To determine whether simvastatin affects the ability of the heart to withstand stress after TBI, injury from myocardial ischemia/reperfusion was determined in vitro. TBI increased the severity of an induced myocardial infarction at 20 and 80 days after irradiation. Simvastatin mitigated the severity of this myocardial infarction at 20 and 80 days following TBI. It is concluded simvastatin mitigated the increases in risk factors for cardiac disease and the extent of cardiac disease following TBI. This statin may be developed as a medical countermeasure for the mitigation of radiation-induced cardiac disease.

Cardiac disease is a frequent and significant adverse event associated with radiotherapy for cancer. Identifying the underlying mechanism responsible for radiation injury to the heart will allow interventions to be developed. In the present study, we tested if local kidney irradiation results in remodeling of the shielded, nontargeted heart. One kidney, two kidneys, or the total body of male WAG and Dahl SS rats were irradiated with 10 Gy of X-rays. Local kidney irradiation resulted in systemic hypertension, increased BUN, infiltration of T lymphocytes, natural killer cells, and macrophages into the renal cortex and medulla, and renal fibrosis. Local irradiation of kidneys in WAG rats resulted in remodeling in the nontargeted heart after 120 days, manifested by perivascular fibrosis and increased interventricular septal thickness, but was not seen in Dahl SS rats due to a high baseline level of fibrosis in the sham-irradiated animals. Genetic depletion of T cells mitigated the nephropathy after local kidney irradiation, indicating a role for the immune system in mediating this outcome. Local kidney irradiation resulted in a cascade of pro-inflammatory cytokines and low-molecular weight metabolites into the circulation associated with transmission of signals resulting in pathologic remodeling in the nontargeted heart. A new model is proposed whereby radiation-induced cardiac remodeling in susceptible animals is indirect, with lower hemi body organs such as the kidney exporting factors into the circulation that cause remodeling outside of the irradiated field in the shielded, nontargeted heart. This nontargeted effect appears to be mediated, in part, by the immune system.

Propranolol is a widely used beta blocker that consists of a racemic mixture of R and S stereoisomers. Only the S stereoisomer has significant activity against the beta-adrenergic receptor. A fortuitous clinical observation was made in an infant who received propranolol for cardiac disease, and regression of a hemangioma of infancy was noted. This has led to the widespread use of propranolol for the treatment of large and life-threatening hemangiomas of infancy. Infants receiving propranolol require monitoring to ensure that they do not suffer from side effects related to beta blockade. The exact mechanism of activity of propranolol in hemangioma of infancy is unknown. In this study, we treated hemangioma stem cells with both beta blockade active S- and inactive R-propranolol and looked for genes that were coordinately regulated by this treatment. Among the genes commonly downregulated, Angiopoietin-like 4 (ANGPTL4) was among the most regulated. We confirmed that propranolol isomers downregulated ANGPTL4 in endothelial cells, with greater downregulation of ANGPTL4 using the beta blockade inactive R-propranolol. ANGPTL4 is present in human hemangiomas of infancy. Finally, R-propranolol inhibited the growth of bEnd.3 hemangioma cells in vivo. The implication of this is that hemangioma growth can be blocked without the side effects of beta blockade. Given that humans have been exposed to racemic propranolol for decades and thus to R-propranolol, clinical development of R-propranolol for hemangiomas of infancy and other angiogenic diseases is warranted.

Long-duration space exploratory missions to the Earth's moon and the planet Mars are actively being planned. Such missions will require humans to live for prolonged periods beyond low earth orbit where astronauts will be continuously exposed to high energy galactic cosmic rays (GCRs). A major unknown is the potential impact of GCRs on the risks of developing degenerative cardiovascular disease, which is a concern to NASA. A ground-based rat model has been used to provide a detailed characterization of the risk of long-term cardiovascular disease from components of GCRs at radiation doses relevant to future human missions beyond low earth orbit. Six month old male WAG/RijCmcr rats were irradiated at a ground-based charged particle accelerator facility with high energy ion beams broadly representative of GCRs: protons, silicon and iron. Irradiation was given either as a single ion beam or as a combination of three ion beams. For the doses used, the single ion beam studies did not show any significant changes in the known cardiac risk factors and no evidence of cardiovascular disease could be demonstrated. In the three ion beam study, the total cholesterol levels in the circulation increased modestly over the 270 day follow up period, and inflammatory cytokines were also increased, transiently, 30 days after irradiation. Perivascular cardiac collagen content, systolic blood pressure and the number of macrophages found in the kidney and in the heart were each increased 270 days after irradiation with 1.5 Gy of the three ion beam grouping. These findings provide evidence for a cardiac vascular pathology and indicate a possible threshold dose for perivascular cardiac fibrosis and increased systemic systolic blood pressure for complex radiation fields during the 9 month follow up period. The development of perivascular cardiac fibrosis and increased systemic systolic blood pressure occurred at a physical dose of the three ion beam grouping (1.5 Gy) that was much lower than that required to show similar outcomes in earlier studies with the same rat strain exposed to photons. Further studies with longer follow up periods may help determine whether humans exposed to lower, mission-relevant doses of GCRs will develop radiation-induced heart disease.