Zonulin is an inflammatory protein first discovered by Fasano and his team in 2000. It helps regulate leakiness in the gut by opening and closing the spaces or "junctions" between cells in the lining of the digestive tract. (1) Zonulin is normally present in the intestines to control the passage of fluids, macromolecules, and leukocytes, but this protein appears to be overexpressed in patients with autoimmune conditions, resulting in increased intestinal permeability. (2)

Intestinal hyperpermeability occurs when there’s a breakdown in the function of zonulin, allowing larger particles such as bacteria, toxins, and partially digested food particles through the intestinal walls to the bloodstream, where the immune system generates a reaction to clear them out. In genetically-susceptible individuals, these substances can eventually elicit an exaggerated or erroneous response, and the body can begin to assault its own tissue. (3)

Zonulin up-regulation seems to precede the onset of the disease, providing a possible link between increased intestinal permeability, environmental exposure to non–self-antigens, and the development of autoimmunity. (4) Drago et al., (2006) concluded that gliadin, a class of proteins found in wheat, activates Zonulin signalling irrespective of the genetic expression of autoimmunity, leading to increased intestinal permeability to macromolecules. (5)

Panaxea’s Zonulin1 possesses extensive therapeutic effects.  In a study by Chen et al., (6), MDCK cell model was used to determine the permeability characteristics and interaction between the major components of Zonulin, including saikosaponin, paeoniflorin, naringin and glycyrrhizic acid. The combined incubation of four major components had a powerful sorbefacient effect than a single drug used alone which maybe regulated by tight junctions.

Bupleurum falcatum (Bupleurum chinensis) , contains Saikosaponin (SAI). SAI may be effective for reducing neuroinflammation-mediated neurodegeneration through suppressing NF-κB-mediated inflammatory pathways. It dose-dependently attenuated production of NO, iNOS mRNA, and ROS by 30-50%. It reduced LPS-mediated increases in the mRNA levels of IL-6, IL-1β, and TNF-α by approximately 30-70% without affecting cell viability. (7)

A broad spectrum of in vitro and in vivo research has proved that Radix Bupleuri extracts, saikosaponin a, saikosaponin d, saikosaponin c, and saikosaponin b2, exhibit evident anti-inflammatory, antitumor, antiviral, anti-allergic, immunoregulation, and neuroregulation activities mainly through NF-κB, MAPK or other pathways. 15 clinical preparations approved by CFDA remarkably broaden the application of Radix Bupleuri. (8). In addition SAI can enhance the absorption of paeoniflorin (PF) in Caco-2 cell monolayer, which may be related to SAI's ability to regulate intercellular tight junctions among Caco-2 cells. (9)

Paeoniae Alba (Paeoniae lactiflora) contains Peroniflorin (PF), a unique therapeutic agent for the treatment of MS and CFS and illustrated the underlying mechanism of PF from a new perspective. (10) PF influenced Th17 cells via suppressing the expression of co-stimulatory molecules and the production of interlukin-6 (IL-6) of dendritic cells (DCs) (11,12).

Naringen (NA), found in Citrus aurantium , has an anti-inflammatory, anti-oxidant and anti-apoptotic potential effect at colorectal sites as it modulates the production and expression oxidative mediators such as malondialdehyde (MDA) and myeloperoxidase (MPO), colonic nitric oxide (NO) and xanthine oxidase (XO), thus reducing DNA damage in inflammatory bowel disease. (13) NA prevented colitis and colorectal carcinogenesis through suppressing robust ER stress-induced autophagy in colorectal mucosal cells. Naringin could develop a promising therapeutic agent for the prevention of ulcerative colitis and colorectal tumour. (14)

NA reduced the incidence, delayed the onset, and attenuated the symptoms of the animal form of MS, which were accompanied by reduced immune cell infiltration and demyelination in the spinal cord. Additionally, the pro-inflammatory CD4+ T cell subsets Th1, Th9, and Th17 cells together with their respective transcription factors T-bet, PU.1, and RORγt were reduced in both the central nervous system (CNS) and lymph nodes of EAE mice. (15)

According to in vivo studies, liquorice root extract was found to prevent the rise in the amount of immune-complexes related to autoimmune diseases like systemic lupus erythematosus. Ju, et al., (1989) reported that flavonoids from liquorice are currently the strongest natural antioxidants known. (16,17)

Lactobacillus acidophilus

Tight Junction Regulation

Non-steroidal anti-inflammatory drugs cause enterocyte damage inducing an increase of intestinal permeability. Tight junctions are the key structures in the permeability of the intestinal mucosa. ZO-1 is a tight junction associated protein considered a good marker of their integrity. It has been suggested that probiotics could play a protective role in the intestinal barrier function. Montalto, et al (2004)  determined, in vitro, whether the heat-killed Lactobacillus acidophilus strain LB (LaLB) with its spent culture supernatant protects tight junctions of HT-29 cells from aspirin (ASA) damage.  Immunofluorescence analysis showed a fragmented and granulous ZO-1 staining, after ASA treatment. Using both ASA and LaLB with its spent culture supernatant together, we found a fine continuous linear web at cell-cell contacts similarly to control. Western blot revealed that ASA inhibited ZO-1 expression and LaLB with its spent culture supernatant counteracted this effect. Conclusions: This pilot study shows, for the first time, the protective effect of LaLB with its spent culture supernatant on tight junctions from ASA damage. These results suggest that probiotics could play a role in the prevention of ASA-induced alterations of intestinal permeability. (18)

Colonic Inflammation

In 15 elderly individuals lyophilized Bifidobacterium bifidum (BB) and Lactobacillus acidophilus (LA) were administered in capsules (two capsules 4 times per day) for 28 days, while in 10 elderly controls placebo were given the same posology and for an equal period of time. The effects of this treatment on the immune system both at the periphery or the intestinal level were investigated. Results show that BB and LA significantly reduced the colonic inflammatory infiltration, without altering T, B and Leu7+ cell percentage. At the same time, a significant increase of B cell frequency in the peripheral blood was noted, in comparison to controls. The overall results suggest that the regular administration of BB and LA leads to a modulation of the immunological and inflammatory response in elderly subjects. (19)

Protective properties on epithelial cells from damage caused by gliadin.

Celiac disease (CD) is a common chronic autoimmune enteropathy caused by gluten intake. To date, the only therapy for CD is the complete exclusion of dietary sources of grains and any food containing gluten. It has been hypothesized that the intestinal microbiota is somehow involved in CD. Specific probiotics have been found to digest or alter gluten polypeptides. It has also been demonstrated that some bacterial species belonging to the genera Lactobacillus, including L.Acidophilus and Bifidobacterium exert protective properties on epithelial cells from damage caused by gliadin. (20)

References

1. 2015. https://www.npr.org/sections/thesalt/2015/12/09/459061317/a-protein-in-the-gut-may-explain-why-some-cant-stomach-gluten

2. Jacob, A. (2013) Today’s Dietitian. Vol. 15 No. 2 P. 38

3. http://drstephaniedavis.com/tag/zonulin/

4. 2012, DOI: https://doi.org/10.1016/j.cgh.2012.08.012

5. Scand J Gastroenterol. 2006 Apr;41(4):408-19. DOI: 10.1080/00365520500235334

6. Ruonan Chen, Chenlin Shen, Qingqing Xu, Yaru Liu, Bo Li, Cheng Huang, Taotao Ma, Xiaoming Meng, Maomao Wu & Jun Li (2017) The permeability characteristics and interaction of main components from Si-Ni-San in a MDCK epithelial cell monolayer model, Xenobiotica, DOI: 10.1080/00498254.2017.1359433

7. Park, Wook Ha, et al. "Ethanol extract of Bupleurum falcatum and saikosaponins inhibit neuroinflammation via inhibition of NF-κB." Journal of ethnopharmacology 174 (2015): 37-44.

8. Bochuan Yuan, Rui Yang, Yongsheng Ma, Shan Zhou, Xiaodong Zhang & Ying Liu (2017) A systematic review of the active saikosaponins and extracts isolated from Radix Bupleuri and their applications, Pharmaceutical Biology, 55:1, 620-635

9. Zhongguo Zhong Yao Za Zhi. 2012 Jun;37(12):1850-4.

10. Scientific Reports 2017 doi:10.1038/srep41887

11. 2011, DOI: 10.3390/molecules16119600

12. 2017, doi:10.1038/srep41887

13. 2014, doi: 10.7555/JBR.27.20120082

14. 2018, https://doi.org/10.1080/15384047.2018.1453971

15. 2018, https://doi.org/10.1016/j.jnutbio.2017.12.004

16. Alonso J. Tratado de Fitofármacos y Nutracéuticos. www.fitoterapia.net. Barcelona: Corpus, 2004; 905-911.

17. Acta Pharmaceutica Sinicia 1989; 24(11):807-812.

18. Montalto M, Maggiano N, Ricci R, Curigliano V, Santoro L, Di Nicuolo F, Vecchio F, M, Gasbarrini A, Gasbarrini G, Lactobacillus acidophilus Protects Tight Junctions from Aspirin Damage in HT-29 Cells. Digestion 2004;69:225-228

19. C. De Simone, A. Ciardi, A. Grassi, S. Lambert Gardini, S. Tzantzoglou, V. Trinchieri, S. Moretti & E. Jirillo (1992) Effect ofBifidobacterium bifidum and Lactobacillus acidophilus on gut mucosa and peripheral blood B lymphocytes,Immunopharmacology and Immunotoxicology, 14:1-2, 331-340, DOI: 10.3109/08923979209009228-

20. Luís Fernando de Sousa Moraes, Lukasz Marcin Grzeskowiak, et al. Intestinal Microbiota and Probiotics in Celiac Disease Clin. Microbiol. Rev. 2014 27(3): 482-489; published 30 June 2014; doi:10.1128/CMR.00106-13

Long COVID and Depression

Post-acute sequelae of COVID-19 (PASC, “Long COVID”) pose a significant global health challenge. The pathophysiology is unknown, and no effective treatments have been found to date. Several hypotheses have been formulated to explain the aetiology of PASC, including viral persistence, chronic inflammation, hypercoagulability, and autonomic dysfunction. Here, we propose a mechanism that links all four hypotheses in a single pathway and provides actionable insights for therapeutic interventions. Authors found that PASC are associated with serotonin reduction. Viral infection and type I interferon-driven inflammation reduce serotonin through three mechanisms: diminished intestinal absorption of the serotonin precursor tryptophan; platelet hyperactivation and thrombocytopenia, which impacts serotonin storage; and enhanced MAO-mediated serotonin turnover.

Peripheral serotonin reduction, in turn, impedes the activity of the vagus nerve and thereby impairs hippocampal responses and memory. These findings provide a possible explanation for neurocognitive symptoms associated with viral persistence in Long COVID, which may extend to other post-viral syndromes (1).

Depression is a kind of mental illness accompanied by complex aetiology and pathogenesis in clinic. With the quickening pace of circadian rhythm and increase of life pressure in modern society, the incidence of depression is increasing year by year. Nowadays, some typical antidepressant Western medicines, such as selective serotonin re-uptake inhibitors (SSRI) and tricyclic antidepressants (TCA), have been used as the main therapeutic drugs in clinic. Unfortunately, administration of these drugs will result in severe adverse reactions, slow treatments, and low cure rates, thus obviously they cannot be used for a long term.

Si ni San (Bupleuri radix, Paeoniae radix alba , Aurantii fructus immaturus , and Glycyrrhizae radix et Rhizoma) , which originated from Treatise on Febrile Diseases written by Zhang zhongjing, is a prescription widely applied in clinic for curing mental illness and a basic Chinese herbal formula for modern treatment of depression (2).

The combination of Radix Bupleuri and Radix Paeoniae Alba, which is used to soothe the liver and relieve depression, has antidepressant effects, but the mechanisms of the effects are still unclear. In this study, a rat model of chronic unpredictable mild stress was established as a model of depression, and proteomics analysis was used to explore the potential mechanisms of this combination in alleviating depression. Biological information analysis was performed on the selected differential proteins, and the enriched pathways mainly included the Jak-STAT signaling pathway, valine, leucine, and isoleucine degradation, and oxidative phosphorylation. The expression of key proteins included metallothionein-1, cyclin-dependent kinase, ubiquitin carboxyl-terminal hydrolase-1, and Cryab was further verified by western blotting, and the results which were consistent with the proteomics results, confirmed the reliability of the proteomic analysis. The antidepressant mechanism of combined Radix Bupleuri and Radix Paeoniae Alba treatment may be related to the oxidative stress response, neuroplasticity, the immune response, and neuroprotection (3)

References