William T. Gunning

Background: Prior to the COVID-19 pandemic, the etiology of postural orthostatic tachycardia syndrome (POTS) remained elusive. Since the pandemic, a newly recognized disorder, termed Long COVID, has emerged with a significant subset of patients developing dysautonomia and a multitude of comorbidities consistent with POTS. Aim: The aim of this study was to determine if pre-pandemic POTS and Long COVID POTS share a common inflammatory-associated biomarker profile. Methods: Volunteers were recruited for four study groups; patients diagnosed with POTS prior to the pandemic, Long COVID-associated POTS, SARS-CoV-2-recovered controls, and naïve controls. All participants completed a COMPASS-31 survey and a medical history questionnaire. Plasma biomarkers of the innate and adaptive immune system were quantified using a custom multiplex bead assay and ELISAs. Results: Both POTS cohorts demonstrated indistinguishable and significant elevations in 14 of the 15 measured biomarkers including markers of the NLRP3 axis (Caspase-1p20, interleukins IL-1β, IL-18), regulatory cytokine IL-10, and immune activation markers (sCD40L, sCD40, sCD30) compared to controls. Multivariate PERMANOVA analysis revealed no significant difference in global cytokine profiles between the two POTS cohorts. Random Forest classification accurately distinguished POTS from controls, with IL-18 emerging as the most important feature. Conclusions: These associative findings suggest that pre-pandemic POTS and Long COVID-associated POTS share a distinct inflammatory profile among measured cytokines. The identification of IL-18 as a key biomarker, alongside Caspase-1p20 and other inflammatory cytokines, are compatible with inflammasome-related signaling. Further investigation is necessary to characterize the role of the inflammasome, platelet activation, and immune dysregulation in POTS and Long COVID.

BACKGROUND: Previously, we demonstrated that the ketone body, β-hydroxybutyrate, is a potent antihypertensive and reno-protective metabolite in Dahl Salt-Sensitive rats. However, the mechanism by which β-hydroxybutyrate confers these beneficial effects is understudied. Here we focused on determining whether the reno-protective effect of β-hydroxybutyrate is due to its known ability to epigenetically remodel chromatin via histone β-hydroxybutyrylation. METHODS: We used the same animal protocol previously used for the discovery of the reno-protective effect of β-hydroxybutyrate. Briefly, postweaning, male and female Dahl Salt-Sensitive rats were split into 2 groups and supplemented with or without 1,3-butanediol for 6 weeks. At euthanasia, circulating β-hydroxybutyrate was quantitated. Renal homogenates were examined for histone 3 lysine 9 β-hydroxybutyrylation, chromatin occupancy, transcriptomic and proteomic profiles with validations RESULTS: Rats supplemented with 1,3-butanediol had higher circulating β-hydroxybutyrate, renal histone β-hydroxybutyrylation, and significant remodeling of chromatin. Notably, regions of the genome associated with lipid catabolism were predominantly in an open chromatin configuration, leading to active transcription and translation. The most highly upregulated gene actively transcribed and translated was Hmgcs2 (3-hydroxy-3-methylglutaryl CoA synthase 2), a gene responsible for the biosynthesis of β-hydroxybutyrate in mitochondria. In contrast, regions with more compact chromatin structures contained immune function genes, Ptprc (protein tyrosine phosphatase receptor type C) and Lcp1 (lymphocyte cytosolic protein 1), which were suppressed. CONCLUSIONS: These results reveal that renal epigenetic histone β-hydroxybutyrylation is a novel mechanism by which transcriptional regulation of both energy metabolism and immune function occur concomitantly and contribute to renoprotection in the hypertensive Dahl rat.

Introduction: Postural orthostatic tachycardia syndrome (POTS), a type of dysautonomia, has been an enigma to many healthcare providers. As many as 80% of coronavirus disease 2019 (COVID-19) long-hauler patients meet the diagnostic criteria for POTS, highlighting awareness of this debilitating multisystem disorder. The etiology of POTS has not been entirely defined, but researchers have speculated that an immunological stressor such as a viral infection might be an initiating event. Prior to the pandemic, we reported that POTS patients have a bleeding diathesis with platelet dense granule storage pool deficiency (δ-SPD).Methods: This report presents a prospective case–control study (n = 252) involving four cohorts, comprising two groups of POTS patients and two groups of healthy controls, to evaluate abnormal bleeding and patient demographics. We compared POTS patients and controls that were naïve to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus with subjects that had been infected and subsequently developed POTS or who recovered healthy. Questionnaires were employed to assess bleeding tendencies and the severity of clinical symptoms commonly reported with POTS. We utilized electron microscopy to assess platelet dense granules and enzyme-linked immunosorbent assay (ELISA) to assess COVID-19 and Epstein–Barr viral titers.Results: The most common bleeding symptom was easy bruising in POTS patients naïve to COVID-19 (79.7%) and POTS post-COVID-19 patients (90.5%). Both groups had δ-SPD with means of 2.52 ± 0.9 and 2.44 ± 0.9 DG/PL, respectively, in contrast to a mean of 4.33 ± 0.6 DG/PL for controls naïve to SARS-CoV-2 infection and 4.19 ± 1.0 DG/PL for controls recovered from the virus (p < 0.001).Discussion: We found that the results between the two POTS groups have no statistically significant difference. Our results identify an additional comorbidity (δ-SPD) in COVID-19 “long haulers”/post-acute sequela of COVID-19 (PASC) patients, frequently seen in POTS, that could explain several disparate symptoms often a??ecting the severity of the condition.

Translation: The University of Toledo Journal of Medical Sciences is the online journal launched by the University of Toledo. Manuscripts will be considered on the understanding that they report original work and are not under consideration for publication by any other journal. The journal publishes original articles reporting experimental results of basic or clinical research, case reports, and reviews. The journal uses a single blind peer review system and each manuscript, based on the results presented in its original submission, will be evaluated by two student reviewers and one faculty reviewer. This process will provide an opportunity for medical students, graduate students, residents, fellows and faculty to publish research observation in a timely manner.

Translation: The University of Toledo Journal of Medical Sciences is the online journal launched by the University of Toledo. Manuscripts will be considered on the understanding that they report original work and are not under consideration for publication by any other journal. The journal publishes original articles reporting experimental results of basic or clinical research, case reports, and reviews. The journal uses a single blind peer review system and each manuscript, based on the results presented in its original submission, will be evaluated by two student reviewers and one faculty reviewer. This process will provide an opportunity for medical students, graduate students, residents, fellows and faculty to publish research observation in a timely manner.

Surveillance of the renal allograft recipient is essential when monitoring renal function to detect the early onset of rejection and alter therapeutic treatments to treat acute rejection or other causes and improve long-term graft function. If renal function begins to deteriorate, a renal biopsy is often indicated to assess the Banff grade of potential rejection or other causes, especially in the setting of polyoma BK viral load elevation. Although BK infection in the allograft is asymptomatic, reactivation of the virus is known to be associated with the acceleration of pathologic change and a poor outcome in the allograft. BK reactivation in a transplant kidney is not uncommon, and determining inflammation related to the virus versus acute rejection is paramount for appropriate immunosuppressive therapy management. We identified a concomitant polyoma BK virus and West Nile Virus (WNV) infection in two renal transplant patients which, to our knowledge, has not previously been reported. However, other concomitant infections have been reported in renal allografts including BK virus and cytomegalovirus (CMV), CMV and hepatitis C (HCV), and HCV and human immunodeficiency virus (HIV). As WNV has become endemic in many regions of the United States, and since the transmission of the virus via transplanted organs is associated with significant morbidity and mortality, it may be prudent to consider serologic screening for WNV in living donors prior to organ procurement. Regardless, the observation we made and report here should underscore the potential for concomitant viral infections that may be masked when a renal allograft has a significant inflammatory response to BK virus.

Qualitative platelet disorders remain rare and varied. We describe here 2 additional patients with giant platelets, thrombocytopenia, deficiency in alpha granules and the presence of membranous inclusions within the cytoplasm. Collectively known as Medich syndrome, we further elucidated structural and clinical features of this rare syndrome. Platelets obtained from 2 patients with macro-thrombocytopenia were evaluated by electron microscopy. Structural findings were correlated with clinical characteristics. The defining morphologic feature found in the platelets of these patients is the presence of long, tubular inclusions consisting of several layers of membrane wrapped around a core of cytoplasm. These inclusions may deform the discoid shape of the platelet. In addition, abnormal giant alpha granules are present. Clinically all patients in the current report and review of the literature had mucosal bleeding and were often misdiagnosed as having immune related thrombocytopenia. To date five cases of Medich giant platelet syndrome have been reported. The cases are unified by the ultrastructural findings of abnormal alpha granules and unusual cytoplasmic scrolls. All patients experienced mucosal bleeding, however many clinical, biologic and genetic characteristics of this rare disorder remain to be determined.

A significant number of postural orthostatic tachycardia syndrome (POTS) patients have platelet delta granule storage pool deficiency (δ-SPD). The etiology of POTS is unknown but a number of laboratories, including ours, have reported elevations of G-protein-coupled adrenergic receptor and muscarinic acetylcholine receptor autoantibodies in POTS patients, detected by a variety of techniques, suggesting that the disorder is an autoimmune condition. Thus, it could also be considered an inflammatory disease. In a pilot study, we investigated a limited number of platelet-related cytokines and chemokines and discovered many that were elevated. This case–control study validates our pilot study results that POTS patients have an activated innate immune system. Plasma of 35 POTS patients and 35 patients with unexplained bleeding symptoms and categorized as “non-POTS” subjects was analyzed by multiplex flow cytometry to quantify 16 different innate immune system cytokines and chemokines. Electron microscopy was used to quantify platelet dense granules. Ten of 16 biomarkers of inflammation were elevated in plasma from POTS patients compared to non-POTS subjects, with most of the differences extremely significant, with p values < 0.0001. Of particular interest were elevations of IL-1β and IL-18 and decreased or normal levels of type 1 interferons in POTS patients, suggesting that the etiology of POTS might be autoinflammatory. All POTS patients had δ-SPD. With a growing body of evidence that POTS is an autoimmune disease and having elevations of the innate immune system, our results suggest a potential T-cell-mediated autoimmunity in POTS characteristic of a mixed-pattern inflammatory disease similar to rheumatoid arthritis.

As life expectancy continues to increase, clinicians are challenged by age-related renal impairment that involves podocyte senescence and glomerulosclerosis. There is now compelling evidence that lithium has a potent antiaging activity that ameliorates brain aging and increases longevity in Drosophila and Caenorhabditis elegans. As the major molecular target of lithium action and a multitasking protein kinase recently implicated in a variety of renal diseases, glycogen synthase kinase 3β (GSK3β) is overexpressed and hyperactive with age in glomerular podocytes, correlating with functional and histological signs of kidney aging. Moreover, podocyte-specific ablation of GSK3β substantially attenuated podocyte senescence and glomerular aging in mice. Mechanistically, key mediators of senescence signaling, such as p16^INK4A and p53, contain high numbers of GSK3β consensus motifs, physically interact with GSK3β, and act as its putative substrates. In addition, therapeutic targeting of GSK3β by microdose lithium later in life reduced senescence signaling and delayed kidney aging in mice. Furthermore, in psychiatric patients, lithium carbonate therapy inhibited GSK3β activity and mitigated senescence signaling in urinary exfoliated podocytes and was associated with preservation of kidney function. Thus, GSK3β appears to play a key role in podocyte senescence by modulating senescence signaling and may be an actionable senostatic target to delay kidney aging.