Brain fog with compromised ability to concentrate has been the most frequent Long Covid (LC) complaint. This is due to an increased transforming growth factor (TGF) β/interferon (IFN)-γ ratio with consequently increased bradykinin (BKN), especially in Caucasian females. Brain and lung blood vessels “leak.” This same ratio is increased in Alzheimer’s disease (AD), but decreased in Parkinson’s disease (PD), because CD4⁺ and CD8⁺ T cells are differentially affected by the invading associated viruses, e.g., SARS CoV2, HIV, Varicella Zoster (VZV) aka Human Herpesvirus 3 (HHV3), HBV, HCV, …. In Covid-19 CD147 receptors on immune cells are critical in generating the increased TGF-β/IFN-γ and those on endothelial cells, platelets, and erythrocytes are critical to the abnormal microvascular blood flow. ACE2 receptors on pneumocytes and enterocytes enable pulmonary and GI entry, initiating gut dysbiosis. Epigenetics, methylation, magnesium, vitamin D, the B vitamins, and antioxidants suggest that these issues can be surmounted. Biochemical, physiologic, and epidemiologic data are analyzed to answer these questions. An LC model is presented and discussed in the context of the most recent research. Suggestions to avoid these and other worrisome concerns are included. Other topics discussed include estrogen, the gut microbiome, type 2 diabetes (T2D), and homocysteine.

Homocysteine (Hcy) is a sulfur-containing amino acid that is generated during methionine metabolism. Hyperhomocysteinemia (HHcy) is typically defined as levels >15 micro mols/L. Elevated plasma levels of Hcy can be caused by the deficiency of either vitamin B12 or folate. The active role of homocysteine is quite ambivalent: many studies detected its potential impact on neurological events; others try to identify it as one of the possible risk factors of cardiovascular events, but with a complementary and secondary role. HHcy has been reported in many neurologic disorders, including cognitive impairment and stroke, independent of long-recognized factors such as hyperlipidemia, hypertension, diabetes mellitus, and smoking. Nowadays, homocysteine could be considered as a possible link between a common vascular risk factor and potential alterations in degenerative neuronal disorders. HHcy-induced oxidative stress, endothelial dysfunction, inflammation, smooth muscle cell proliferation, and endoplasmic reticulum stress; all these aspects have been considered to play an essential role in the pathogenesis of several diseases, including atherosclerosis, major stroke, and vascular dementia. Specific models of astrocytes impairment in HHcy-mice, which mimic small vessel disease, have been developed with a three-step investigation (at 6, 10, 14 weeks of B6, B9, and B12 detrimental diet in wild type HHcy mouse). These studies found out that after ten weeks on a diet (at the most after 14 weeks), end-feet disruption occurs. This phenomenon is concomitant to reduced vascular labeling for aquaporin -4-water channels, lower protein/mRNA levels for Kir4.1, and BK potassium channels, associated with a higher expression of MMP-9. The most exciting finding is that microglial activation in this mice model was evident since the precocious time of observation (6-week time) and precedes astrocytic changes. Our research aims to review the possible role of HHcy in neurodegenerative disease and small-vessel disease and to understand its pathogenic impact.

These three syndromes - long covid (LC), postural orthostatic tachycardia syndrome (POTS), and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) - have many symptoms in common. The common denominator remains elusive. The blood brain barrier (BBB) has been a barrier not only to microbes and toxins but also to understanding pathogenetic links. There are several areas within the brain that have no BBB. These are known as circumventricular organs (CVOs) and their location relative to CNS nuclei that direct autonomic and neuroendocrine functions is provocative in the quest for pathogenesis. In addition the majority afflicted with LC and ME/CFS appear to be those with two MTHFR polymorphisms, present in over 50% of Americans. These polymorphisms elevate homocysteine. When homocysteine is combined with CVOs, the fog of POTS and its paradox are lifted. POTS may represent the intersection of LC and ME/CFS in those with the MTHFR gene (hypermethylation or 677TT). The gut microbiomes of LC and ME/CFS, deficient in butyrates, GABA, and diversity, are then linked with MTHFR genotype 677TT. Reactivation of neurotropic EBV and VZV, due to loss of surveillance by CD4+/CD8+ T cells, is seen as secondary. The oxidative stress generated by homocysteine, loss of glutathione, low fiber diet, and persistent chronic inflammation exhaust available mitochondria and, assisted by BKN and estrogen, exacerbate all the elements of these post viral fatigue syndromes.

Hsp70.1 has dual functions as chaperone protein and lysosomal stabilizer. Previously, we reported that calpain-mediated cleavage of carbonylated Hsp70.1 causes ischemic neuronal death by inducing lysosomal rupture. Recently, we found that the consecutive injections of vegetable oil-peroxidation product ‘hydroxynonenal’ induces hepatocyte death via the similar cascade. As Hsp70.1 is related also to fatty acid β-oxidation in the liver, its deficiency is known to cause accumulation of fat. Genetic deletion of betaine-homocysteine S-methyltransferase (BHMT) was reported to perturb choline metabolism, inducing decrease of phosphatidylcholine with the resultant hepatic steatosis. Here, focusing on disorders of Hsp70.1 and BHMT, we studied the mechanism of hepatocyte degeneration and steatosis, using monkeys after the consecutive injections of synthetic hydroxynonenal. As these monkeys showed a significant impairment of liver functions, the liver tissues without and with hydroxynonenal injections were compared by proteomics, immunoblotting, immunohisto-chemical and electron microscopic analyses. Western blotting showed upregulation of neither Hsp70.1 nor BHMT, but an increased cleavage of both proteins. Proteomics showed downregulation of Hsp70.1, while 2-fold increments of carbonylated BHMT. Hsp70.1 carbonylation was negligible, showing a marked contrast to ischemic neurons which were associated with ~10-fold increments. The control liver histologically showed lipid droplets in Ito cells, but lipid depositions within hepatocytes were very little. In contrast, after hydroxynonenal injections, widespread fatty degeneration and focal coagulation necrosis were observed with accumulation of numerous tiny lipid droplets within and around the degenerating/dying hepatocytes. Electron microscopy showed lysosomal membrane permeabilization/rupture, remarkable dissolution of mitochondria and rough ER membrane, and proliferation of abnormal peroxisomes. It is probable that disruptions of rough ER caused impaired synthesis of Hsp70.1 and BHMT proteins, while impairments of mitochondria and peroxisomes presumably contributed to the sustained generation of reactive oxygen species. Since both Hsp70.1 and BHMT are vulnerable to the long-standing oxidative stressor, hydroxynonenal-induced disorders facilitated degeneration and steatosis of hepatocytes, respectively.