Series introduction. The immuno-neuroendocrine interface

Sodium alterations impair the prognosis of hospitalized patients with COVID-19 pneumonia

OBJECTIVE

Dysnatremia is common in hospitalized patients, often worsening the prognosis in pneumopathies and critical illnesses. Information on coronavirus disease-19 (COVID-19)-related hyponatremia is partially conflicting, whereas data on hypernatremia in this context are scarce. We assessed, in a cohort of COVID-19 inpatients: the prevalence of sodium alterations at admission and throughout their hospitalization; their association with inflammation/organ damage indexes; their short-term prognostic impact.

STUDY DESIGN AND METHODS

117 patients (81 males, 64 ± 13 years) hospitalized for COVID-19 between 1 March and 30 April 2020 were retrospectively followed-up for their first 21 days of stay by collecting all serum sodium measurements, basal CRP and serum lactate levels, maximum IL-6 and information on care setting, required ventilation, length of hospitalization, in-hospital death.

RESULTS

At admission, 26.5% patients had hyponatremia, and 6.8% had hypernatremia. During their hospitalization, 13.7% patients experienced both disorders ('mixed dysnatremia'). Lower sodium levels at admission were correlated with higher C reactive protein (CRP) (P = 0.039) and serum lactate levels (P = 0.019), but not interleukin-6 (IL-6). Hypernatremia and a wider sodium variability were associated with maximum required ventilation, need for ICU assistance and duration of the hospitalization. Mean estimated time to Intensive Care Unit (ICU) admission was 20 days shorter in patients exposed to sodium alterations at any time of their hospital course (log-rank test P = 0.032).

CONCLUSIONS

Sodium alterations frequently affect hospitalized COVID-19 patients. Hyponatremia could indicate pulmonary involvement, whereas hypernatremia is associated to prolonged hospitalization and the need for intensive care/mechanical ventilation, particularly when resulting from prior hyponatremia. Optimizing in-hospital sodium balance is crucial to improve patients' prognosis.

Levels of C-Reactive Protein and Sodium May Differentiate a Perforated Appendix from a Nonperforated Appendix in Children

Background

Acute appendicitis (AA) might be amenable to conservative antibiotic treatment, whereas a perforated appendix (PA) necessitates surgery. We investigated the value of clinical–laboratory markers in distinguishing AA from a PA.

Methods

Retrospectively obtained preoperative parameters for 306 consecutive patients (<18 years) with histologically confirmed appendicitis (AA (n = 237) vs. PA (n = 69)), treated at our institution between January 2014 and December 2017.

Results

A PA was associated with male preponderance, younger age, decreased sodium level and increased white blood cell count, Tzanakis score, C-reactive protein (CRP) level, and CRP-to-lymphocyte ratio (CLR). Upon discrimination analysis, CLR and CRP displayed the highest accuracy in differentiating a PA from AA. Regression analysis identified levels of CRP, sodium, and the Tzanakis score as independent predictors for a PA.

Conclusion

Levels of CLR, CRP, sodium, and Tzanakis score might support decision-making regarding treatment options for pediatric appendicitis.

Hypotheses about sub-optimal hydration in the weeks before coronavirus disease (COVID-19) as a risk factor for dying from COVID-19

To address urgent need for strategies to limit mortality from coronavirus disease 2019 (COVID-19), this review describes experimental, clinical and epidemiological evidence that suggests that chronic sub-optimal hydration in the weeks before infection might increase risk of COVID-19 mortality in multiple ways. Sub-optimal hydration is associated with key risk factors for COVID-19 mortality, including older age, male sex, race-ethnicity and chronic disease. Chronic hypertonicity, total body water deficit and/or hypovolemia cause multiple intracellular and/or physiologic adaptations that preferentially retain body water and favor positive total body water balance when challenged by infection. Via effects on serum/glucocorticoid-regulated kinase 1 (SGK1) signaling, aldosterone, tumor necrosis factor-alpha (TNF-alpha), vascular endothelial growth factor (VEGF), aquaporin 5 (AQP5) and/or Na⁺/K⁺-ATPase, chronic sub-optimal hydration in the weeks before exposure to COVID-19 may conceivably result in: greater abundance of angiotensin converting enzyme 2 (ACE2) receptors in the lung, which increases likelihood of COVID-19 infection, lung epithelial cells which are pre-set for exaggerated immune response, increased capacity for capillary leakage of fluid into the airway space, and/or reduced capacity for both passive and active transport of fluid out of the airways. The hypothesized hydration effects suggest hypotheses regarding strategies for COVID-19 risk reduction, such as public health recommendations to increase intake of drinking water, hydration screening alongside COVID-19 testing, and treatment tailored to the pre-infection hydration condition. Hydration may link risk factors and pathways in a unified mechanism for COVID-19 mortality. Attention to hydration holds potential to reduce COVID-19 mortality and disparities via at least 5 pathways simultaneously.

Effect of CD14/TLR4 antagonist on GnRH/LH secretion in ewe during central inflammation induced by intracerebroventricular administration of LPS

BACKGROUND

Immune stress induced by lipopolysaccharide (LPS) influences the gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) secretion. Presence of LPS interacting Toll-like receptor (TLR) 4 in the hypothalamus may enable the direct action of LPS on the GnRH/LH secretion. So, the aim of the study was to investigate the influence of intracerebroventricular (icv) injection of TLR4 antagonist on GnRH/LH secretion in anestrous ewes during LPS-induced central inflammation. Animals were divided into three groups icv-treated with: Ringer-Locke solution, LPS and TLR4 antagonist followed by LPS.

RESULTS

It was demonstrated that TLR4 antagonist reduced LPS-dependent suppression of GnRH gene expression in the preoptic area and in the medial basal hypothalamus, and suppression of receptor for GnRH gene expression in the anterior pituitary gland. It was also shown that TLR4 antagonist reduced suppression of LH release caused by icv injection of LPS. Central administration of LPS stimulated TLR4 gene expression in the medial basal hypothalamus.

CONCLUSIONS

It was indicated that blockade of TLR4 prevents the inhibitory effect of centrally acting LPS on the GnRH/LH secretion. This suggests that some negative effects of bacterial infection on the hypothalamic-pituitary-gonadal axis activity at the hypothalamic level may be caused by central action of LPS acting through TLR4.

Environmental and Genetic Activation of Hypothalamic BDNF Modulates T-cell Immunity to Exert an Anticancer Phenotype

Macroenvironmental factors, including a patient's physical and social environment, play a role in cancer risk and progression. Our previous studies show that living in an enriched environment (EE) providing complex stimuli confers an anticancer phenotype in mice mediated, in part by a specific neuroendocrine axis, with brain-derived neurotrophic factor (BDNF) as the key brain mediator. Here, we investigated how an EE modulated T-cell immunity and its role in the EE-induced anticancer effects. Our data demonstrated that CD8 T cells were required to mediate the anticancer effects of an EE in an orthotropic model of melanoma. In secondary lymphoid tissue (SLT), an EE induced early changes in the phenotype of T-cell populations, characterized by a decrease in the ratio of CD4 T helper to CD8 cytotoxic T lymphocytes (CTL). Overexpression of hypothalamic BDNF reproduced EE-induced T-cell phenotypes in SLT, whereas knockdown of hypothalamic BDNF inhibited EE-induced immune modulation in SLT. Both propranolol and mifepristone blocked the EE-associated modulation of CTLs in SLT, suggesting that both the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis were involved. Our results demonstrated that enhanced anticancer effect of an EE was mediated at least in part through modulation of T-cell immunity and provided support to the emerging concept of manipulating a single gene in the brain to improve cancer immunotherapy. Cancer Immunol Res; 4(6); 488-97. ©2016 AACR.

Death in pediatric Cushing syndrome is uncommon but still occurs

Cushing syndrome (CS) in children is rare. Delayed diagnosis and treatment of CS may be associated with increased morbidity and, unfortunately, mortality. We performed a retrospective review of all patients with CS under the age of 18 years referred to the National Institutes of Health (NIH) from 1998 to 2013 in order to describe deceased patients among cases of pediatric CS referred to the National Institutes of Health (NIH). The deaths of four children (three females and one male), aged 7.5-15.5 years (mean age 11.2 years) with length of disease 2-4 years, were recorded among 160 (2.5 %) children seen at or referred to the NIH over the last 15 years. All died at different institutions, prior to coming to the NIH (two) or after leaving NIH (two). Presenting symptoms included increasing weight and decreasing height gain, facial plethora, dorsocervical fat pad (webbed neck), striae, headache, vision disturbances, and depression and other mood or behavior changes; there were no differences between how these patients presented and the others in our cohort. The causes of CS in the deceased patients were also not different, in fact, they spanned the entire spectrum of CS: pituitary disease (one), ectopic corticotropin production (one), and primary adrenal hyperplasia (one). In one patient, the cause of CS could not be verified. Three died of sepsis and one due to residual disease and complications of the primary tumor.

CONCLUSIONS

Despite the advances in early diagnosis and treatment of pediatric CS, a 2.5 % mortality rate was identified in a large cohort of patients with this condition referred to an experienced, tertiary care referral center (although these deaths occurred elsewhere). Pediatricians need to recognize the possibility of death, primarily due to sepsis, in a patient with pediatric CS and treat accordingly.

Effects of central injection of anti-LPS antibody and blockade of TLR4 on GnRH/LH secretion during immunological stress in anestrous ewes

The present study was designed to examine the effect of intracerebroventricular (icv) administration of antilipopolysaccharide (LPS) antibody and blockade of Toll-like receptor 4 (TLR4) during immune stress induced by intravenous (iv) LPS injection on the gonadotropin-releasing hormone/luteinizing hormone (GnRH/LH) secretion in anestrous ewes. Injection of anti-LPS antibody and TLR4 blockade significantly (P < 0.01) reduced the LPS dependent lowering amount of GnRH mRNA in the median eminence (ME). Moreover, blockade of TLR4 caused restoration of LH-β transcription in the anterior pituitary decreased by the immune stress. However, there was no effect of this treatment on reduced LH release. The results of our study showed that the blockade of TLR4 receptor in the hypothalamus is not sufficient to unblock the release of LH suppressed by the immune/inflammatory challenges. This suggests that during inflammation the LH secretion could be inhibited directly at the pituitary level by peripheral factors such as proinflammatory cytokines and circulating endotoxin as well.

In vivo time-lapse imaging delineates the zebrafish pituitary proopiomelanocortin lineage boundary regulated by FGF3 signal

The anterior pituitary gland (adenohypophysis) comprises anterior and intermediate lobes (the pars distalis and pars intermedia) arising from placodal ectoderm at the anterior neural ridge. Signaling molecules including SHH, FGF, WNT, BMP and Notch are involved in regulating primordial pituitary proliferation and lineage determination. However, morphogenic events and molecular mechanisms governing anterior and intermediate lobe specification are not clear. Pituitary expression of proopiomelanocortin (POMC), the common precursor for adrenocorticotropin (ACTH) of pars distalis corticotropes and alpha-melanocyte-stimulating hormone (alpha-MSH) of pars intermedia melanotropes, provides a unique marker for anterior and intermediate lobe morphogenesis. We performed time-lapse confocal microscopy lineage tracing in live zebrafish embryos expressing GFP driven by the pomc promoter and show distinct migration pathways of POMC cells destined to the anterior and intermediate lobes. Using morpholino oligonucleotides, we show that hypomorphic FGF3 down-regulation induces specific defects of pars intermedia POMC cells while pomc, growth hormone and prolactin expression remain intact in the pars distalis. This lineage-specific process is independent of the FGF3 effect on early pituitary specifying transcription factors as indicated by normal Lim3 and Pit1 expression in hypomorphic FGF3 morphants. These findings suggest that the FGF3 signal, in addition to its previously described role of regulating progenitor proliferation and survival, delineates the melanotrope and corticotrope lineage boundary, contributing to establishment of the pituitary pars distalis and pars intermedia.

Aldosteronism and peripheral blood mononuclear cell activation: a neuroendocrine-immune interface

Aldosteronism eventuates in a proinflammatory/fibrogenic vascular phenotype of the heart and systemic organs. It remains uncertain whether peripheral blood mononuclear cells (PBMCs) are activated before tissue invasion by monocytes/macrophages and lymphocytes, as is the case for responsible pathogenic mechanisms. Uninephrectomized rats treated for 4 weeks with dietary 1% NaCl and aldosterone (ALDOST, 0.75 microg/h) with or without spironolactone (Spi, 100 mg/kg per daily gavage) were compared with unoperated/untreated and uninephrectomized/salt-treated controls. Before intramural coronary vascular lesions appeared at week 4 of ALDOST, we found (1) a reduction of PBMC cytosolic free [Mg2+]i, together with intracellular Mg2+ and Ca2+ loading, whereas plasma and cardiac tissue Mg2+ were no different from controls; (2) increased H2O2 production by monocytes and lymphocytes together with upregulated PBMC gene expression of oxidative stress-inducible tyrosine phosphatase and Mn2+-superoxide dismutase and the presence of 3-nitrotyrosine in CD4+ and ED-1-positive inflammatory cells that had invaded intramural coronary arteries; (3) B-cell activation, including transcription of immunoglobulins, intracellular adhesion molecule-1, and CC and CXC chemokines and their receptors; (4) expansion of B lymphocyte subset and myosin heavy chain class II-expressing lymphocytes; and (5) autoreactivity with gene expression for antibodies to acetylcholine receptors and a downregulation of RT-6.2, which is in keeping with cell activation and associated with autoimmunity. Spi cotreatment attenuated the rise in intracellular Ca2+, the appearance of oxidative/nitrosative stress in PBMCs and invading inflammatory cells, and alterations in PBMC transcriptome. Thus, aldosteronism is associated with an activation of circulating immune cells induced by iterations in PBMC divalent cations and transduced by oxidative/nitrosative stress. ALDO receptor antagonism modulates this neuroendocrine-immune interface. The full text of this article is available online at http://www.circresaha.org.