Absence of Type I Interferon Autoantibodies or Significant Interferon Signature Alterations in Adults With Post-COVID-19 Syndrome.

Genetic defects in the interferon (IFN) system or neutralizing autoantibodies against type I IFNs contribute to severe COVID-19. Such autoantibodies were proposed to affect post-COVID-19 syndrome (PCS), possibly causing persistent fatigue for >12 weeks after confirmed SARS-CoV-2 infection. In the current study, we investigated 128 patients with PCS, 21 survivors of severe COVID-19, and 38 individuals who were asymptomatic. We checked for autoantibodies against IFN-α, IFN-ß, and IFN-ω. Few patients with PCS had autoantibodies against IFNs but with no neutralizing activity, indicating a limited role of type I IFNs in PCS pathogenesis. In a subset consisting of 28 patients with PCS, we evaluated IFN-stimulated gene activity and showed that it did not correlate with fatigue. In conclusion, impairment of the type I IFN system is unlikely responsible for adult PCS.

Mechanisms and clinical relevance of the bidirectional relationship of viral infections with metabolic diseases.

Viruses have been present during all evolutionary steps on earth and have had a major effect on human history. Viral infections are still among the leading causes of death. Another public health concern is the increase of non-communicable metabolic diseases in the last four decades. In this Review, we revisit the scientific evidence supporting the presence of a strong bidirectional feedback loop between several viral infections and metabolic diseases. We discuss how viruses might lead to the development or progression of metabolic diseases and conversely, how metabolic diseases might increase the severity of a viral infection. Furthermore, we discuss the clinical relevance of the current evidence on the relationship between viral infections and metabolic disease and the present and future challenges that should be addressed by the scientific community and health authorities.

Succinate mediates inflammation-induced adrenocortical dysfunction.

The hypothalamus-pituitary-adrenal (HPA) axis is activated in response to inflammation leading to increased production of anti-inflammatory glucocorticoids by the adrenal cortex, thereby representing an endogenous feedback loop. However, severe inflammation reduces the responsiveness of the adrenal gland to adrenocorticotropic hormone (ACTH), although the underlying mechanisms are poorly understood. Here, we show by transcriptomic, proteomic, and metabolomic analyses that LPS-induced systemic inflammation triggers profound metabolic changes in steroidogenic adrenocortical cells, including downregulation of the TCA cycle and oxidative phosphorylation, in mice. Inflammation disrupts the TCA cycle at the level of succinate dehydrogenase (SDH), leading to succinate accumulation and disturbed steroidogenesis. Mechanistically, IL-1ß reduces SDHB expression through upregulation of DNA methyltransferase 1 (DNMT1) and methylation of the SDHB promoter. Consequently, increased succinate levels impair oxidative phosphorylation and ATP synthesis and enhance ROS production, leading to reduced steroidogenesis. Together, we demonstrate that the IL-1ß-DNMT1-SDHB-succinate axis disrupts steroidogenesis. Our findings not only provide a mechanistic explanation for adrenal dysfunction in severe inflammation, but also offer a potential target for therapeutic intervention.

Clinical improvement of Long-COVID is associated with reduction in autoantibodies, lipids, and inflammation following therapeutic apheresis.

In the aftermath of the COVID-19 pandemic, we are witnessing an unprecedented wave of post-infectious complications. Most prominently, millions of patients with Long-Covid complain about chronic fatigue and severe post-exertional malaise. Therapeutic apheresis has been suggested as an efficient treatment option for alleviating and mitigating symptoms in this desperate group of patients. However, little is known about the mechanisms and biomarkers correlating with treatment outcomes. Here, we have analyzed in different cohorts of Long-Covid patients specific biomarkers before and after therapeutic apheresis. In patients that reported a significant improvement following two cycles of therapeutic apheresis, there was a significant reduction in neurotransmitter autoantibodies, lipids, and inflammatory markers. Furthermore, we observed a 70% reduction in fibrinogen, and following apheresis, erythrocyte rouleaux formation and fibrin fibers largely disappeared as demonstrated by dark field microscopy. This is the first study demonstrating a pattern of specific biomarkers with clinical symptoms in this patient group. It may therefore form the basis for a more objective monitoring and a clinical score for the treatment of Long-Covid and other postinfectious syndromes.

Adrenal Gland Function and Dysfunction During COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic is currently one of the major health concerns worldwide accounting for many deaths and posing a great social and economic burden. Early activation of adrenal hormone secretion is pivotal to surviving systemic microbial infections. In addition, clinical studies demonstrated that glucocorticoids might also be beneficial in reducing disease progression and life deterioration in certain patients with COVID-19. Recent studies demonstrated that SARS-CoV-2 might target the adrenal glands, raising the possibility that at least some COVID-19 complications may be associated with adrenal dysfunction. Whether SARS-CoV-2 infection might cause adrenal dysfunction remains unknown. Histopathological examinations provided evidence that SARS-CoV-2 infection might indeed cause certain structural damage to the adrenal glands, especially concerning its vascular system. However, since no widespread cellular damage to cortical cells was observed, it is less likely that those changes could lead to an immediate adrenal crisis. This assumption is supported by the limited number of studies reporting rather adequate cortisol levels in patients with acute COVID-19. Those studies, however, could not exclude a potential late-onset or milder form of adrenal insufficiency. Although structural damage to adrenal glands is a rarely reported complication of COVID-19, some patients might develop a critical illness-related corticosteroid insufficiency (CIRCI), or iatrogenic adrenal insufficiency resulting from prolonged treatment with synthetic glucocorticoids. In this mini-review article, we aimed at describing and discussing factors involved in the adrenal gland function and possible dysfunction during COVID-19.

Chronic post-COVID-19 syndrome and chronic fatigue syndrome: Is there a role for extracorporeal apheresis?

As millions of patients have been infected by SARS-CoV-2 virus a vast number of individuals complain about continuing breathlessness and fatigue even months after the onset of the disease. This overwhelming phenomenon has not been well defined and has been called "post-COVID syndrome" or "long-COVID" [1]. There are striking similarities to myalgic encephalomyelitis also called chronic fatigue syndrome linked to a viral and autoimmune pathogenesis. In both disorders neurotransmitter receptor antibodies against ß-adrenergic and muscarinic receptors may play a key role. We found similar elevation of these autoantibodies in both patient groups. Extracorporeal apheresis using a special filter seems to be effective in reducing these antibodies in a significant way clearly improving the debilitating symptoms of patients with chronic fatigue syndrome. Therefore, such a form of neuropheresis may provide a promising therapeutic option for patients with post-COVID-19 syndrome. This method will also be effective when other hitherto unknown antibodies and inflammatory mediators are involved.

[Practical recommendations for screening and management of functional disorders of the adrenal cortex in cases of SARS-CoV-2 infections]. / Praktische Empfehlungen zum Screening und Management von Funktionsstörungen der Nebennierenrinde bei einer akuten SARS-CoV-2-Infektion.

Diseases of the adrenal cortex require particular attention during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Firstly, SARS-CoV­2 infections can give rise to extrapulmonary manifestations and cause endocrine disorders, particularly in the adrenal cortex. Furthermore, patients with pre-existing insufficiency of the adrenal cortex or hypercortisonism are particularly at risk from a severe infection such as SARS-CoV­2, to suffer from additional complications or a more severe course of a SARS-CoV­2 infection with a higher mortality. Especially in hemodynamically unstable patients with a SARS-CoV­2 infection, diseases of the adrenal glands should also be considered in the differential diagnostics and if necessary clarified, if this is not already known. Prolonged treatment of patients with a SARS-CoV­2 infection with regimens containing high doses of glucocorticoids can also result in a secondary adrenal insufficiency. In order to address these special aspects, some practical recommendations for the diagnostic and therapeutic management of functional disorders of the adrenal glands in patients with a SARS-CoV­2 infection are therefore presented.

The longevity gene mIndy (I'm Not Dead, Yet) affects blood pressure through sympathoadrenal mechanisms.

Reduced expression of the plasma membrane citrate transporter INDY (acronym I'm Not Dead, Yet) extends life span in lower organisms. Deletion of the mammalian Indy (mIndy) gene in rodents improves metabolism via mechanisms akin to caloric restriction, known to lower blood pressure (BP) by sympathoadrenal inhibition. We hypothesized that mIndy deletion attenuates sympathoadrenal support of BP. Continuous arterial BP and heart rate (HR) were reduced in mINDY-KO mice. Concomitantly, urinary catecholamine content was lower, and the decreases in BP and HR by mIndy deletion were attenuated after autonomic ganglionic blockade. Catecholamine biosynthesis pathways were reduced in mINDY-KO adrenals using unbiased microarray analysis. Citrate, the main mINDY substrate, increased catecholamine content in pheochromocytoma cells, while pharmacological inhibition of citrate uptake blunted the effect. Our data suggest that deletion of mIndy reduces sympathoadrenal support of BP and HR by attenuating catecholamine biosynthesis. Deletion of mIndy recapitulates beneficial cardiovascular and metabolic responses to caloric restriction, making it an attractive therapeutic target.

Exquisite sensitivity of adrenocortical carcinomas to induction of ferroptosis.

Adrenocortical carcinomas (ACCs) are rare and highly malignant cancers associated with poor survival of patients. Currently, mitotane, a nonspecific derivative of the pesticide DDT (1,1-(dichlorobiphenyl)-2,2-dichloroethane), is used as the standard treatment, but its mechanism of action in ACCs remains elusive. Here we demonstrate that the human ACC NCI-H295R cell line is remarkably sensitive to induction of ferroptosis, while mitotane does not induce this iron-dependent mode of regulated necrosis. Supplementation with insulin, transferrin, and selenium (ITS) is commonly used to keep NCI-H295R cells in cell culture. We show that this supplementation prevents spontaneous ferroptosis, especially when it contains polyunsaturated fatty acids (PUFAs), such as linoleic acid. Inhibitors of apoptosis (zVAD, emricasan) do not prevent the mitotane-induced cell death but morphologically prevent membrane blebbing. The expression of glutathione peroxidase 4 (GPX4) in H295R cells, however, is significantly higher when compared to HT1080 fibrosarcoma cells, suggesting a role for ferroptosis. Direct inhibition of GPX4 in H295R cells led to high necrotic populations compared to control, while cotreatment with ferrostatin-1 (Fer-1) completely reverted ferroptosis. Interestingly, the analysis of public databases revealed that several key players of the ferroptosis pathway are hypermethylated and/or mutated in human ACCs. Finally, we also detected that growth hormone-releasing hormone (GHRH) antagonists, such as MIA602, kill H295R cells in a nonapoptotic manner. In summary, we found elevated expression of GPX4 and higher sensitivity to ferroptosis in ACCs. We hypothesize that instead of treatment with mitotane, human adrenocortical carcinomas may be much more sensitive to induction of ferroptosis.

RNA-seq analysis of LPS-induced transcriptional changes and its possible implications for the adrenal gland dysregulation during sepsis.

Activation of the adrenal gland stress response is of utmost importance to survive sepsis. Experimental and clinical evidence exists demonstrating that adrenal gland often develops functional and structural damage due to sepsis with mechanisms remaining largely unknown. In the present study, we have used RNA Sequencing (RNA-Seq) technology to analyze changes in adrenal transcriptome elucidated by bacterial LPS. We aimed to find particularly alterations in genes that were previously not reported to be involved in the adrenal gland dysregulation in contexts of sepsis. Our results demonstrate that systemic administration of LPS significantly altered expression of 8458 genes as compared to saline injected animals. The subsequent quality and functional analysis of these gene signatures revealed that LPS-induced highly homogenous transcriptional response in total upregulating 4312 and downregulating 4146 genes. Furthermore, functional annotation analysis together with gene enrichment set analysis (GSEA) clearly demonstrated that adrenal response to LPS involved alterations in multiple pathways related to the inflammatory response along with previously unexplored activation of the hypoxia pathway. In addition, LPS strongly downregulated genes involved in the adrenal homeostasis, development, and regeneration. Those alterations were subsequently verified in clinically relevant cecal ligation and puncture (CLP)-induced sepsis model. Collectively, our study demonstrates that RNA-seq is a very useful method that can be applied to search for new unexplored pathways potentially involved in adrenal gland dysregulation during sepsis.

An Update on Addison's Disease.

Addison's disease - the traditional term for primary adrenal insufficiency (PAI) - is defined as the clinical manifestation of chronic glucocorticoid- and/or mineralocorticoid deficiency due to failure of the adrenal cortex which may result in an adrenal crisis with potentially life-threatening consequences. Even though efficient and safe pharmaceutical preparations for the substitution of endogenous gluco- and mineralocorticoids are established in therapy, the mortality in patients with PAI is still increased and the health-related quality of life (HRQoL) is often reduced.PAI is a rare disease but recent data report an increasing prevalence. In addition to the common "classical" causes of PAI like autoimmune, infectious, neoplastic and genetic disorders, other iatrogenic conditions - mostly pharmacological side effects (e. g., adrenal haemorrhage associated with anticoagulants, drugs affecting glucocorticoid synthesis, action or metabolism and some of the novel anti-cancer checkpoint inhibitors) are contributing factors to this phenomenon.Due to the rarity of the disease and often non-specific symptoms at least in the early stages, PAI is frequently not considered resulting in a delayed diagnosis. Successful therapy is mainly based on adequate patient education as a cornerstone in the prevention and management of adrenal crisis. A focus of current research is in the development of pharmacokinetically optimized glucocorticoid preparations as well as regenerative therapies.

Transcriptional Analysis of Sepsis-Induced Activation and Damage of the Adrenal Endothelial Microvascular Cells.

Bacterial sepsis is a serious threat to the body homeostasis and is often associated with high mortality in non-coronary intensive stations. In order to survive sepsis, rapid activation of the hypothalamus-pituitary-adrenal gland axis and sympathomedullary system is necessary. In many patients with sepsis, the function of those two arms of the stress system is dysregulated with underlying mechanisms remaining unknown. In our previous experimental studies, we have demonstrated that LPS-induced systemic inflammation and CLP-induced peritonitis can result in adrenal gland damage. Histological and transcriptomic analysis revealed a potential involvement of the adrenal microvascular endothelium in this process. However, our knowledge about the function of adrenal microvascular cells during sepsis is scarce. In the present study, we have characterized transcriptomic alterations in isolated mouse adrenal microvascular endothelial cells induced by systemic administration of bacterial LPS. Our results revealed that LPS induced a distinct transcriptomic profile in the adrenal microvascular cells, including multiple genes regulating inflammation, activation of the coagulation cascade and vascular permeability. Activation of those genes may be potentially involved in the damage to the microvascular endothelium and altogether contribute to the sepsis-mediated adrenal dysregulation.

The adrenal gland microenvironment in health, disease and during regeneration.

The adrenal gland is a key component of the stress system in the human body. Multiple direct and paracrine interactions between different cell types and their progenitors take place within the adrenal gland microenvironment. These unique interactions are supported by high vascularization and the adrenal cortex extracellular matrix. Alterations in the adrenal gland microenvironment are known to influence the progression of several pathological conditions, such as obesity and sepsis, and to be influenced by these disorders. For example, it has been suggested that activation of immune-adrenal crosstalk during sepsis induces elevated adrenal glucocorticoid levels, whereas crosstalk between adrenocortical cells and sonic hedgehog responsive stem cells was found to contribute to the increased size of the adrenal cortex during obesity. By contrast to sepsis, where activation of adrenal glucocorticoid production has protective effects, chronic exposure to high levels of glucocorticoids induces adverse effects, typically manifested in patients with Cushing syndrome, such as increased body weight, dyslipidemia, glucose intolerance, and hypertension. Therefore, a better understanding of factors involved in the regulation of the adrenal gland microenvironment is crucial. This review highlights bidirectional interactions occurring between the adrenal gland microenvironment and systemic responses during obesity and sepsis. Furthermore, it presents and discusses recent advancements and challenges in attempts to restore or regenerate adrenal gland function, including the use of oxygenated immune-isolating devices.

Adrenal Gland Microenvironment and Its Involvement in the Regulation of Stress-Induced Hormone Secretion during Sepsis.

Survival of all living organisms depends on maintenance of a steady state of homeostasis, which process relies on its ability to react and adapt to various physical and emotional threats. The defense against stress is executed by the hypothalamic-pituitary-adrenal axis and the sympathetic-adrenal medullary system. Adrenal gland is a major effector organ of stress system. During stress, adrenal gland rapidly responds with increased secretion of glucocorticoids (GCs) and catecholamines into circulation, which hormones, in turn, affect metabolism, to provide acutely energy, vasculature to increase blood pressure, and the immune system to prevent it from extensive activation. Sepsis resulting from microbial infections is a sustained and extreme example of stress situation. In many critical ill patients, levels of both corticotropin-releasing hormone and adrenocorticotropin, the two major regulators of adrenal hormone production, are suppressed. Levels of GCs, however, remain normal or are elevated in these patients, suggesting a shift from central to local intra-adrenal regulation of adrenal stress response. Among many mechanisms potentially involved in this process, reduced GC metabolism and activation of intra-adrenal cellular systems composed of adrenocortical and adrenomedullary cells, endothelial cells, and resident and recruited immune cells play a key role. Hence, dysregulated function of any of these cells and cellular compartments can ultimately affect adrenal stress response. The purpose of this mini review is to highlight recent insights into our understanding of the adrenal gland microenvironment and its role in coordination of stress-induced hormone secretion.

Mortality of Septic Mice Strongly Correlates With Adrenal Gland Inflammation.

OBJECTIVES: Sepsis and septic shock are commonly present in the ICU and accompanied by significant morbidity, mortality, and cost. The frequency of secondary adrenal insufficiency in sepsis remains open to debate and a challenge to identify and treat appropriately. Animal models of sepsis using genetic or surgical initiation of adrenal insufficiency resulted in increased mortality, but the mechanisms are still unclear. The present study investigates the impact of adrenal inflammation in septic mice challenged with cecal ligation and puncture. DESIGN: Prospective experimental study. SETTING: University laboratory. SUBJECTS: C57BL/6N wild-type mice. INTERVENTIONS: Sepsis, induced by cecal ligation and puncture for 24 and 48 hours. MEASUREMENTS AND MAIN RESULTS: Both septic and control mice were carefully monitored (every 30 min) for up to 48 hours and divided into survivors and nonsurvivors. We observed a significant and massive increase of interleukin-6, interleukin-1ß, and tumor necrosis factor-α in adrenal protein extracts of nonsurvivors compared with sham animals and survivors. This pattern was partly reflected in liver and lung but not in plasma samples. Notably, a significant increase in nonsurvivors compared with survivors was only found for lung interleukin-6. In line with these findings, we detected a higher degree of leukocyte infiltration and hemorrhage in the adrenal glands of deceased mice. Evaluation of the hypothalamic-pituitary-adrenal axis response in these animals revealed an increase of adrenocorticotropic hormone, which was only partly reflected in the corticosterone level. Notably, using the adrenocorticotropic hormone stimulation test, we found an impaired adrenocorticotropic hormone response, particularly in nonsurvivors, which significantly correlated with the number of infiltrated leukocytes. CONCLUSIONS: Cecal ligation and puncture-induced murine sepsis induces a strong inflammatory response in the adrenal glands, which is accompanied by cell death and hemorrhage. Our data suggest that mortality and adrenal incapacitation are associated with the degree of adrenal inflammation, thereby underscoring the importance of adrenal function on survival.

The role of adrenal gland microenvironment in the HPA axis function and dysfunction during sepsis.

Sepsis and septic shock in response to bacterial or viral infections remain the major health problem worldwide. Despite decades of intensive research and improvements in medical care, severe sepsis is associated with high mortality. Rapid activation of the adrenal gland glucocorticoid and catecholamine production is a fundamental component of the stress response and is essential for survival of the host. However, in many critically ill patients this homeostatic function of the adrenal gland is often impaired. In these patients, plasma levels of adrenocorticotropic hormone (ACTH) and cortisol are often dissociated. This has been attributed to the stimulatory action of non-ACTH factors within the adrenal gland such as cytokines, and recently with decreased cortisol metabolism and suppressed ACTH synthesis. Regulation of the hypothalamus-pituitary-adrenal (HPA) axis function during sepsis is a complex process which involves various immune and neuroendocrine interactions occurring at the levels of the central nervous system (CNS) and the adrenal gland. A coordinated interaction of numerous cell types and systems within the adrenal gland is involved in the sustained adrenal glucocorticoid production. This review article describes and discusses recent experimental findings regarding the role of adrenal gland microenvironment including the adrenal vasculature and the immune-adrenal crosstalk in the disregulated HPA axis during sepsis conditions. In summary, in addition to the reduced cortisol breakdown and related ACTH suppression, sepsis-mediated chronic activation of the immune-adrenal crosstalk and vascular dysfunction may contribute to the HPA axis dysregulation found in septic patients.