An interesting new study was published today in a top medical journal. It describes how a common and safe "liver drug" shuts the door on COVID before it can infect our cells. This is serious research, not fringe theories.
The drug is ursodeoxycholic acid (UDCA). What they do not mention is the strange situation where this is both a drug and a dietary supplement -- and the dietary supplement is the more "active" form of the substance. UDCA is activated when bound with the amino acid taurine (and taurine itself helps protect the retina). When activated this way, UDCA is called TUDCA.
TUDCA is the active compound in bear bile, which was used in several traditional medical systems. Some people still refer to TUDCA as "bear bile."
Bile is produced in the liver and stored in the gall bladder. It functions as part of our digestive process. Bear bile used to be extracted from Asian black bears. The harvest of bear bile was extremely controversial to say the least. Thankfully, it is no longer taken from bears, but synthesized in an ethical and sustainable manner. The main ingredients of bear bile are ursodeoxycholic acid (UDCA) and tauroursodeoxycholic acid (TUDCA), with TUDCA considered the activated form.
TUDCA is a dietary supplement that has been of interest to many glaucoma patients for a long time. Douglas Rhee, MD, wrote a section on it for a consensus paper for a major glaucoma organization more than a dozen years ago. In fact TUDCA (or bear bile) has a history of use for improving vision going back thousands of years in traditional Chinese medicine (Cidian 2004; Ventura 2009).
I'll explain more about TUDCA and the neuroprotection it may offer for the optic nerve below. But first, here is the abstract from today's newly published study in the prestigious journal Nature.
Prevention of SARS-CoV-2 infection through the modulation of viral host receptors, such as ACE21, could represent a new chemoprophylactic approach for COVID-19 complementing vaccination2,3. However, the mechanisms controlling ACE2 expression remain elusive.
Here, we identify the farnesoid X receptor (FXR) as a direct regulator of ACE2 transcription in multiple COVID19-affected tissues, including the gastrointestinal and respiratory systems.
We then use the over-the-counter compound z-guggulsterone (ZGG) and the off-patent drug ursodeoxycholic acid (UDCA) to reduce FXR signalling and downregulate ACE2 in human lung, cholangiocyte and intestinal organoids and in the corresponding tissues in mice and hamsters.
We demonstrate that UDCA-mediated ACE2 downregulation reduces susceptibility to SARS-CoV-2 infection in vitro, in vivo and in human lungs and livers perfused ex situ.
Furthermore, we illustrate that UDCA reduces ACE2 expression in the nasal epithelium in humans.
Finally, we identify a correlation between UDCA treatment and positive clinical outcomes following SARS-CoV-2 infection using retrospective registry data, and confirm these findings in an independent validation cohort of liver transplant recipients.
In conclusion, we identify a novel function of FXR in controlling ACE2 expression and provide evidence that modulation of this pathway could be beneficial for reducing SARS-CoV-2 infection, paving the road for future clinical trials. [end of abstract]
Turning our attention to TUDCA's neuroprotective properties, here is a small sample of scientific studies available from PubMed:
Tauroursodeoxycholic acid: a potential therapeutic tool in neurodegenerative diseases - PubMed
In recent years, hydrophilic bile acids, particularly tauroursodeoxycholic acid (TUDCA), have shown important anti-apoptotic and neuroprotective activities, with numerous experimental and clinical evidence suggesting their possible therapeutic use as disease-modifiers in neurodegenerative diseases.
Experimental evidence on the mechanisms underlying TUDCA's neuroprotective action derives from animal models of Alzheimer's disease, Parkinson's disease, Huntington's diseases, amyotrophic lateral sclerosis (ALS) and cerebral ischemia. Preclinical studies indicate that TUDCA exerts its effects not only by regulating and inhibiting the apoptotic cascade, but also by reducing oxidative stress, protecting the mitochondria, producing an anti-neuroinflammatory action, and acting as a chemical chaperone to maintain the stability and correct folding of proteins.
Furthermore, data from phase II clinical trials have shown TUDCA to be safe and a potential disease-modifier in ALS. ALS is the first neurodegenerative disease being treated with hydrophilic bile acids.
The study's conclusion, along with the usual caveats, is:
TUDCA stands as a promising treatment for neurodegenerative diseases.
The bile acid TUDCA and neurodegenerative disorders: An overview - PubMed
Bear bile has been used in Traditional Chinese Medicine for thousands of years due to its therapeutic potential and clinical applications. The tauroursodeoxycholic acid (TUDCA), one of the acids found in bear bile, is a hydrophilic bile acid and naturally produced in the liver by conjugation of taurine to ursodeoxycholic acid (UDCA).
Several studies have shown that TUDCA has neuroprotective action in several models of neurodegenerative disorders (ND), including Alzheimer's disease, Parkinson's disease, and Huntington's disease, based on its potent ability to inhibit apoptosis, attenuate oxidative stress, and reduce endoplasmic reticulum stress in different experimental models of these illnesses.
Our research extends the knowledge of the bile acid TUDCA actions in neurodegenerative disorders and the mechanisms and pathways involved in its cytoprotective effects on the brain, providing a novel perspective and opportunities for treatment of these diseases.
You can find many more interesting studies on TUDCA's neuroprotective potential.
Tauroursodeoxycholic acid (TUDCA) is neuroprotective in a chronic mouse model of Parkinson's disease - PubMed
Neuroprotective Effects of Tauroursodeoxicholic Acid Involves Vascular and Glial Changes in Retinitis Pigmentosa Model - PubMed
Comparative Analysis of Urso- and Tauroursodeoxycholic Acid Neuroprotective Effects on Retinal Degeneration Models - PubMed
Bile Acids as Key Modulators of the Brain-Gut-Microbiota Axis in Alzheimer's Disease - PubMed
Tauroursodeoxycholic acid alleviates secondary injury in spinal cord injury mice by reducing oxidative stress, apoptosis, and inflammatory response - PubMed
Tauroursodeoxycholic Acid (TUDCA)-Lipid Interactions and Antioxidant Properties of TUDCA Studied in Model of Photoreceptor Membranes - PubMed
Co-delivery of glial cell-derived neurotrophic factor (GDNF) and tauroursodeoxycholic acid (TUDCA) from PLGA microspheres: potential combination therapy for retinal diseases - PubMed
Oral Ursodeoxycholic Acid Crosses the Blood Retinal Barrier in Patients with Retinal Detachment and Protects Against Retinal Degeneration in an Ex Vivo Model - PubMed
TUDCA is non-prescription, relatively inexpensive and has a good safety record at doses up to 750 mg/day. If you decide to try it, be sure to buy it from a reputable company.