Exposure to environmental airborne particulate matter caused wide-ranged transcriptional changes and accelerated Alzheimer's-related pathology: A mouse study

Air pollution poses a significant threat to human health, though a clear understanding of its mechanism remains elusive. In this study, we sought to better understand the effects of various sized particulate matter from polluted air on Alzheimer's disease (AD) development using an AD mouse model. We exposed transgenic Alzheimer's mice in their prodromic stage to different sized particulate matter (PM), with filtered clean air as control. After 3 or 6 months of exposure, mouse brains were harvested and analyzed. RNA-seq analysis showed that various PM have differential effects on the brain transcriptome, and these effects seemed to correlate with PM size. Many genes and pathways were affected after PM exposure. Among them, we found a strong activation in mRNA Nonsense Mediated Decay pathway, an inhibition in pathways related to transcription, neurogenesis and survival signaling as well as angiogenesis, and a dramatic downregulation of collagens. Although we did not detect any extracellular Aβ plaques, immunostaining revealed that both intracellular Aβ1-42 and phospho-Tau levels were increased in various PM exposure conditions compared to the clean air control. NanoString GeoMx analysis demonstrated a remarkable activation of immune responses in the PM exposed mouse brain. Surprisingly, our data also indicated a strong activation of various tumor suppressors including RB1, CDKN1A/p21 and CDKN2A/p16. Collectively, our data demonstrated that exposure to airborne PM caused a profound transcriptional dysregulation and accelerated Alzheimer's-related pathology.

Cigarette smoke stimulates clonal expansion of Jak2V617F and Tet2-/- cells

Introduction

Somatic mutations in myeloid growth factor pathway genes, such as JAK2, and genes involved in epigenetic regulation, such as TET2, in hematopoietic stem cells (HSCs) leads to clonal hematopoiesis of indeterminate potential (CHIP) which presents a risk factor for hematologic malignancy and cardiovascular disease. Smoking behavior has been repeatedly associated with the occurrence of CHIP but whether smoking is an environmental inflammatory stressor in promoting clonal expansion has not been investigated.

Methods

We performed in vivo smoke exposures in both wildtype (WT) mice and transplanted mice carrying Jak2V617F mutant and Tet2 knockout (Tet-/-) cells to determine the impact of cigarette smoke (CS) in the HSC compartment as well as favoring mutant cell expansion.

Results

WT mice exposed to smoke displayed increased oxidative stress in long-term HSCs and suppression of the hematopoietic stem and progenitor compartment but smoke exposure did not translate to impaired hematopoietic reconstitution in primary bone marrow transplants. Gene expression analysis of hematopoietic cells in the bone marrow identified an imbalance between Th17 and Treg immune cells suggesting a local inflammatory environment. We also observed enhanced survival of Jak2V617F cells exposed to CS in vivo and cigarette smoke extract (CSE) in vitro. WT bone marrow hematopoietic cells from WT/Jak2V617F chimeric mice exposed to CS demonstrated an increase in neutrophil abundance and distinct overexpression of bone marrow stromal antigen 2 (Bst2) and retinoic acid early transcript 1 (Raet1) targets. Bst2 and Raet1 are indicative of increased interferon signaling and cellular stress including oxidative stress and DNA damage, respectively. In chimeric mice containing both WT and Tet2-/- cells, we observed an increased percentage of circulating mutant cells in peripheral blood post-cigarette smoke exposure when compared to pre-exposure levels while this difference was absent in air-exposed controls.

Conclusion

Altogether, these findings demonstrate that CS results in an inflamed bone marrow environment that provides a selection pressure for existing CHIP mutations such as Jak2V617F and Tet2 loss-of-function.

The connection between heart rate variability (HRV), neurological health, and cognition: A literature review

The heart and brain have bi-directional influences on each other, including autonomic regulation and hemodynamic connections. Heart rate variability (HRV) measures variation in beat-to-beat intervals. New findings about disorganized sinus rhythm (erratic rhythm, quantified as heart rate fragmentation, HRF) are discussed and suggest overestimation of autonomic activities in HRV changes, especially during aging or cardiovascular events. When excluding HRF, HRV is regulated via the central autonomic network (CAN). HRV acts as a proxy of autonomic activity and is associated with executive functions, decision-making, and emotional regulation in our health and wellbeing. Abnormal changes of HRV (e.g., decreased vagal functioning) are observed in various neurological conditions including mild cognitive impairments, dementia, mild traumatic brain injury, migraine, COVID-19, stroke, epilepsy, and psychological conditions (e.g., anxiety, stress, and schizophrenia). Efforts are needed to improve the dynamic and intriguing heart-brain interactions.

One Acute Exposure to E-Cigarette Smoke Using Various Heating Elements and Power Levels Induces Pulmonary Inflammation

Background

Electronic cigarettes (eC) may not be entirely benign. There is a lack of data on the effect of a single acute exposure of eC vapor using various heating sources and power settings upon lung injury. The purpose of this study was to determine if an acute exposure with eC vapor heated with different heating elements and power levels induced inflammatory changes in the lungs and heart.

Methods

Rats were exposed to pure air or received a single, 4-h exposure to eC vapor. The devices used either a stainless steel (SS) or nichrome (NC) heating element randomized to a low or high atomization power (45 versus 70 W). Rats were euthanized within 48 h of exposure.

Results

The eC groups showed accumulation of inflammatory cells in bronchial lumen, near the pleura, and within the alveolar spaces. The numbers of inflammatory cells per field in the lung parenchyma were significantly greater in the rats exposed to eC groups vs. the air group. There were significantly higher inflammatory gene expression changes in the lungs of animals assigned to 70 W power. We observed that eC vapor generated using burnt coils were toxic and could cause acute respiratory distress and myocarditis.

Conclusion

In conclusion, one 4-h exposure to eC vapor, in the absence of vitamin E oil or nicotine, significantly increased lung inflammation. Effects were seen after exposures to vapor generated using SS and NC heating elements at either high or low power. Vapor from devices with burnt coils can negatively affect the heart and lung.

Exposure to environmentally relevant concentrations of ambient fine particulate matter (PM2.5) depletes the ovarian follicle reserve and causes sex-dependent cardiovascular changes in apolipoprotein E null mice

BACKGROUND

Fine particulate matter (PM_2.5) exposure accelerates atherosclerosis and contains known ovotoxic chemicals. However, effects of exposure to PM_2.5 on the finite ovarian follicle pool have hardly been investigated, nor have interactions between ovarian and cardiovascular effects. We hypothesized that subchronic inhalation exposure to human-relevant concentrations of PM_2.5 results in destruction of ovarian follicles via apoptosis induction, as well as accelerated recruitment of primordial follicles into the growing pool. Further, we hypothesized that destruction of ovarian follicles enhances the adverse cardiovascular effects of PM_2.5 in females.

RESULTS

Hyperlipidemic apolipoprotein E (Apoe) null ovary-intact or ovariectomized female mice and testis-intact male mice were exposed to concentrated ambient PM_2.5 or filtered air for 12 weeks, 5 days/week for 4 h/day using a versatile aerosol concentration enrichment system. Primordial, primary, and secondary ovarian follicle numbers were decreased by 45%, 40%, and 17%, respectively, in PM_2.5-exposed ovary-intact mice compared to controls (P < 0.05). The percentage of primary follicles with granulosa cells positive for the mitosis marker Ki67 was increased in the ovaries from PM_2.5-exposed females versus controls (P < 0.05), consistent with increased recruitment of primordial follicles into the growing pool. Exposure to PM_2.5 increased the percentages of primary and secondary follicles with DNA damage, assessed by γH2AX immunostaining (P < 0.05). Exposure to PM_2.5 increased the percentages of apoptotic antral follicles, determined by TUNEL and activated caspase 3 immunostaining (P < 0.05). Removal of the ovaries and PM_2.5-exposure exacerbated the atherosclerotic effects of hyperlipidemia in females (P < 0.05). While there were statistically significant changes in blood pressure and heart rate variability in PM_2.5-compared to Air-exposed gonad-intact males and females and ovariectomized females, the changes were not consistent between exposure years and assessment methods.

CONCLUSIONS

These results demonstrate that subchronic PM_2.5 exposure depletes the ovarian reserve by increasing recruitment of primordial follicles into the growing pool and increasing apoptosis of growing follicles. Further, PM_2.5 exposure and removal of the ovaries each increase atherosclerosis progression in Apoe-/- females. Premature loss of ovarian function is associated with increased risk of osteoporosis, cardiovascular disease and Alzheimer's disease in women. Our results thus support possible links between PM_2.5 exposure and other adverse health outcomes in women.

Ambient ultrafine particles activate human monocytes: Effect of dose, differentiation state and age of donors

Exposure to ambient particulate matter (PM) has been linked to adverse pulmonary and cardiovascular health effects. Activation of both inflammatory and oxidative stress pathways has been observed and may be a probable cause of these outcomes. We tested the hypothesis that in human monocytes, PM-induced oxidative and inflammatory responses are interrelated. A human monocytic cell line (THP-1) was used to determine if dose and differentiation state plays a role in the cellular response after a 24hr exposure to particles. Primary human monocytes derived from eight female, non-smoker donors (aged: 21, 24, 27, 28, 48, 49, 54 & 60yo) were used to determine if the age of donors modulates the response. Cells were treated with aqueous suspensions of ambient ultrafine particles (UFP, defined as smaller than 0.2µm in size) or a media control for 24hr. After exposure, reactive oxygen species (ROS) formation was increased irrespective of dose or differentiation state of THP-1 cells. In the primary human monocytes, ROS formation was not significantly changed. The release of the proinflammatory cytokine, tumor necrosis factor alpha (TNF-α), was dose-dependent and greatest in differentiated compared to undifferentiated THP-1 cells exposed to UFP. In the Primary human monocytes, TNF-α secretion was increased irrespective of the age of the donor. Our results suggest that after a 24hr exposure to particles, general reactive oxygen species formation was nonspecific and uncorrelated to cytokine secretion which was consistently enhanced. Cytokines play an important role in orchestrating many immune responses and thus the ability of ambient particles to enhance robust secretion of a proinflammatory cytokine from primary human monocytes, and how this may influence the response to pathogens and alter disease states, needs to be further evaluated.

Long-term sequelae of hearing impairment in congenital hypothyroidism

Hearing loss and its functional consequences were evaluated retrospectively in children with congenital hypothyroidism. From a cohort of 101 children followed longitudinally to evaluate newborn screening, 75 with previous hearing tests were studied. Fifteen (20%) were found to have hearing problems. Of these, nine had unilateral or sensorineural loss mostly at high frequencies, five had a conductive loss, and one had both problems. Hearing impaired children differed from children with normal hearing in age of treatment onset (22 vs 14 days) but not disease severity or duration. A comparison of language and auditory processing skills at ages 3, 5, and 7 years revealed that early speech was delayed in hearing impaired children, whereas deficits persisted in later receptive language and auditory discrimination skills. Comparing hearing impaired children and children with normal hearing with matched control subjects at grade 3 showed that hearing impaired children were poorer readers because of less adequate phonologic processing skills.

Ototoxicity of carboplatin: comparing animal and clinical models at the Hospital for Sick Children

Carboplatin was introduced to the paediatric population as an alternative chemotherapeutic agent in the management of various malignant neoplasms, including sarcomas of the head and neck, in the hope that it would have fewer side effects than pre-existing agents. While many investigators have considered the ototoxicity of this drug only incidentally, others have presumed it to be of negligible importance. A recent animal model of its use has demonstrated damage to the inner hair cells of the cochlea, particularly at the basal turn, with a corresponding high incidence of hearing loss. Similarly, 11 of 22 patients who received this agent at the Hospital for Sick Children over the past 2 years demonstrated a sensorineural hearing loss in the 4 to 12 kHz range. This complication occurred as early as after the first dose and was generally progressively worse with subsequent doses. Consequently, we recommend careful audiologic monitoring of children receiving this agent.

Characteristics of a DNA probe (pa3'HVR) when used for paternity testing

DNA probes that detect polymorphic loci in the human genome are finding widespread application in many areas of genetic testing. Paternity testing represents one area for the application of probe technology; this report presents data obtained in a paternity testing program with a probe (pa3'HVR) derived from a locus (D16S85) approximately 8 kilobases (kb) downstream from the alpha globin gene complex on chromosome 16. The pa3'HVR probe used under stringent conditions of hybridization detects a highly polymorphic locus in chromosomal DNA digested with Pvu 2 restriction endonuclease. Alleles at the D16S85 locus were grouped into 58 size bins differing from one another by 100 base pairs in the black and white populations. The most common alleles detected in whites fell into the 2.3-kb group with a collective frequency of 0.1849. In blacks, the most common allele group is 2.0 kb with a collective frequency of 0.1333. The probe was used for restriction fragment length polymorphism mapping in conjunction with standard paternity testing techniques in 100 paternity cases. Thirty direct exclusions were encountered in the 100 cases with standard testing methods, versus 27 exclusions with the pa3'HVR probe alone. Four exclusions detected with standard methods were not detected with the probe and one exclusion detected with the probe was missed by standard testing. The probability of excluding a falsely accused man by use of the pa3'HVR probe was approximately 90 percent. In cases where exclusions were not encountered, the data obtained with the pa3'HVR probe increased the paternity index calculated from standard testing by about 16-fold.2+ informative for paternity testing.

Raynaud's phenomenon following cytotoxic chemotherapy successfully managed by dorsal sympathectomy

Raynaud's phenomenon of varying severity is not uncommon following cytotoxic chemotherapy especially when combinations including bleomycin are used. We present a case in which severe Raynaud's progressing to trophic ulceration was successfully managed by dorsal sympathectomy.