Positive Health Online

^aAritson Cruz, Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Porto, Portugal - arycrz19@hotmail.com.
^bLígia Pimentel, Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Porto, Portugal - lpimentel@porto.ucp.pt.
^cProf. Tito Fernandes, ACIVET Faculty of Veterinary Medicine, Lisbon University, Portugal. -procattitofernandes@gmail.com.
^dProf. Manuela Pintado, Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina – Laboratório  ssociado, Escola Superior de Biotecnologia, Porto, Portugal - mpintado@porto.ucp.pt.

Over the past 10 years, there has been much research effort focused on trying to understand the role of mushroom nutrition in slowing the onset and progression of neurodegenerative conditions. The critical question is ‘How does mushroom supplementation promote neurological health?’ In working to answer to this question, scientists have established that, in rodents, specific mushroom species are able to reduce neuroinflammation via upregulation of Lipoxin A4 (a potential endogenous anti-inflammatory mediator),[1,2] and increase neurological reserve by generating new neurons.[3] There is also an increasing body of evidence to suggest that mushroom nutrition might also act indirectly via the gut microbiota.[4,5]

The link between the gastrointestinal system and the gut microbiota is commonly known as the Gut–Brain Axis...

• The bidirectional communication between the gut and the central/enteric nervous systems.
• Often refers to the role of the microbiota in sending biochemical signals to the brain.
• The microbiota produces many neuroactive molecules. Changes in the microbiota can correlate with changes in neuroinflammatory chemicals, and can directly stimulate the vagus nerve.
• Likewise, stress can cause changes in the microbiota and intestinal lining.
• An unbalanced microbiota can, by implication, lead to compromised CNS function, and potentially disorders such as anxiety, depression and autism, and neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease.

The Interaction Between the Microbiota and Nervous System

The gut-brain axis is a complex system of interactions between the gut microbiota and the enteric and central nervous systems. It has been hypothesised that this bi-directional communication may be partly mediated via neurotransmitters.[6]

• The gut microbiota influences the brain. The microbiota produces neurotransmitters (such as serotonin and gamma-aminobutyric acid) and specific bacterial metabolites, which affect the enteric and central nervous systems and impact immune and inflammatory responses.[7,8]
  It is no surprise, therefore, that there is growing evidence supporting the concept that there is a link between dysbiosis and human behaviour, autism and neurodegenerative conditions such as Alzheimer’s disease and Parkinson’s disease.[7,9-11]
• Brain function influences the microbiota. Host neurotransmitters affect gut function and microhabitat via changes in mucus production, motility, intestinal permeability and inflammatory response.[7] It is also understood that host neurotransmitters are able to bind to receptors on bacterial cell walls, and thus influence the function of components of the microbiota.[7]

However, the study of this complex and multifaceted interaction is in its infancy, and the mechanisms behind the gut-brain axis remain to be fully determined.

ISAPP Definition of Prebiotics

In December of 2016, the International Scientific Association for Probiotics and Prebiotics (ISAPP) reviewed the latest definition of prebiotic, defining it as…

“…a substrate that is selectively utilized by host microorganisms conferring a health benefit.”[17]

The word ‘substrate’ refers to a substance from which an organism obtains nourishment, and therefore excludes compounds that function as antimicrobial substances or other microorganisms; i.e. the ‘substrate’ should be a part of the normal metabolism of the bacterial cells and not function as an inhibitor.

Shaping the Microbiota Using Prebiotics

One useful way of actively modifying the gut microbiota is through the ingestion of prebiotics. Prebiotics are selectively fermented by host bacteria, resulting in the production of Short Chain Fatty Acids (SCFA), some of which are regarded as being beneficial for the microbiota and its environment.[12-16]

SCFAs:

• Reduce luminal pH, preventing colonisation by pathogenic microorganisms, and increasing the absorption of some nutrients;
• Act as the main energy source for colonocytes;
• Have a major role in gluconeogenesis and lipid biosynthesis;
• Help preserve the gut barrier, a complex, multilayer system, which constitutes a physical and functional barrier.

Bioactive Properties of Mushroom Nutrition – Exploratory Studies

Over the past 3 years, Mycology Research Laboratories* has been working with a group of researchers, led by Professor Manuela Pintado at the School of Biotechnology in the Catholic University in Porto (Portugal), to determine the bioactive properties of mushroom nutrition. Based on a previous study that noted the impact of Coriolus versicolor on the microbiota,[4] Professor Pintado chose to conduct studies on this strain of mushroom to seek to understand its characteristics and activity as a prebiotic.

Figure 1: Simulation of gastrointestinal conditions [19(adapted)]

Prebiotic Activity is Strain-Dependent

A study to assess the prebiotic potential of mushroom biomass compared the growth of different probiotic cultures (Lactobacillus acidophilus L10, Lactobacillus paracasei L26, Bifidobacterium longum BG6 and Bifidobacterium animalis Bo) in the presence of Coriolus versicolor biomass, glucose or a negative control.[18] The mushroom biomass was either intact or had been submitted to a simulated gastrointestinal tract (GIT) digestion (to simulate conditions that would follow ingestion of the biomass) (see Figure 1).

Results (Table 1) suggest that Coriolus versicolor (biomass) has a potential strain-dependent prebiotic effect, with higher activity on the Bifidobacterium animalis Bo.

Table 1: Bacterial growth (vs glucose) in the presence of Coriolus versicolor biomass.
Bacterial growth after the 48th hour of incubation at 37ºC. Growth was measured by enumeration of viable microorganisms (CFU/mL). ++, same level of growth compared with glucose; +, weaker growth compared with glucose; - no growth.

Further analysis of the incubation medium revealed that fermentation of Coriolus versicolor biomass by Lactobacillus paracasei L26 increased the concentrations of acetic and lactic acid (vs the glucose and negative controls).

Together, these results suggest that Coriolus versicolor acts as a substrate for fermentation by beneficial bacterial species, and that the consequent production of SCFA by some of these species might contribute to conditions (lower pH and preservation of the gut barrier) that support a healthy gut.

Pathogen Adhesion Inhibition

The adhesion of pathogens can be inhibited through two means:

• Receptor analogues, which are usually carbohydrates that mimic the epithelial receptor sites and bind to the bacterial adhesin, preventing the bacteria from adhering to the host cells;
• Adhesin analogues that bind to the host cells’ surface receptors, thereby blocking the binding of pathogens.

Prebiotic Activity Inhibits Cell Adhesion

Prebiotic agents can have an indirect inhibitory effect on the growth of pathogenic bacteria through a combination of their selective fermentation by probiotic bacteria in the colon (as discussed above) and their anti-adhesive properties (adhesion of undesirable bacteria to host tissue being the first step in pathogenesis). Therefore, prebiotic supplementation is another potential strategy to inhibit the growth of undesirable bacteria.[20]

Professor Pintado tested the inhibitory effect of the pre-digested Coriolus versicolor biomass on three major intestinal pathogens: Salmonella enterica (ATCC 13076), Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC CRM 8739).[18] Its effect on adhesion of these pathogens to mucus was evaluated in vitro using mucin (Type II Sigma-Aldrich) as a model of intestinal mucus. The results showed an inhibitory effect of the Coriolus versicolor substrate on adhesion, especially in the case of Salmonella enterica, although the mechanism of this inhibition is, as yet, unknown. Additional studies are needed in mixed cultures and faecal samples in order to assess the bioactivity in an environment with a complex bacterial population.

Figure 2: Postulated prebiotic activity of Coriolus versicolor (Mycology Research Laboratories) based on findings of Professor Pintado et al.[18]
++, same level of growth compared with glucose; +, weaker growth compared with glucose; 0, no growth. 

Study Conclusions

1. Coriolus versicolor biomass may constitute a new source of bioactive molecules (as a prebiotic), with the ability inhibit pathogen infection of the microbiota;
2. Coriolus versicolor (biomass) has a potential strain-dependent prebiotic effect, with high activity on the Bifidobacterium animalis Bo and a partial effect on Lactobacillus paracasei L26;
3. Coriolus versicolor biomass has potential inhibitory adhesion effect, especially against Salmonella enterica.

Potential of Coriolus versicolor for Neurological Support

The in vitro work outlined above demonstrates that Coriolus versicolor biomass has a bifidogenic effect and induces positive changes in the gut microbiota. Acting as a prebiotic, Coriolus versicolor would support the immune system by maintaining the health of the microbiota, and potentially support neurological functions that are under the influence of the microbiota.

While this and previous work suggests a potential future role for mushroom nutrition in ameliorating a variety of chronic inflammation-mediated human conditions associated with neurodegeneration, there are, to date, no clinical data to confirm any beneficial effects in patients.

Professor Tito Fernandes, from the Faculty of Veterinary Medicine, Lisbon University states:

“In vivo work with rodents has revealed that mushroom (Coriolus and Hericium) supplementation stimulates lipoxin production, reducing excessive tissue injury and chronic inflammation, and promoting a neuroprotective action. Clinical work and studies on the aetiology are now required.”[21]

^*Mycology Research Laboratories – supplier of Coriolus versicolor biomass: The Spires Suite 5BB, 8 Adelaide St, Luton LU1 5BJ, UK. www.mycologyresearch.com.

Funding was provided by Fundação e Tecnologia (FCT, Lisbon Portugal) through the project UID/Multi/50016/2013 and also by Mycology Research Laboratories Ltd.

References

1. Trovato A, Siracusa R, Di Paola R, Scuto M, Fronte V, Koverech G, Luca M, Serra A, Toscano MA, Petralia A, Cuzzocrea S, Calabrese V. Redox modulation of cellular stress response and lipoxin A4 expression by Coriolus versicolor in rat brain: relevance to Alzheimer’s disease pathogenesis. Neurotoxicology 2016a;53:350-358. doi: 10.1016/j.neuro.2015.09.012
2. Trovato A, Siracusa R, Di Paola R, Scuto M, Ontario ML, Bua O, Di Mauro P, Toscano MA, Petralia CCT, Maiolino L, Serra A, Cuzzocrea S, Calabrese V. Redox modulation of cellular stress response and lipoxin A4 expression by Hericium erinaceus in rat brain: relevance to Alzheimer’s disease pathogenesis. Immunity & Ageing 2016b;13:23. doi:10.1186/s12979-016-0078-8
3. Ferreiro E, Pita IR, Mota SI, Valero J, Ferreira NR, Fernandes T, Calabrese V, Fontes-Ribeiro CA , Pereira FC , Rego AC. Coriolus versicolor biomass increases dendritic arborization of newly-generated neurons in mouse hippocampal dentate gyrus. Oncotarget 2018;9(68): 32929–32942.  doi: 10.18632/oncotarget.25978
4. Yu Z-T, Liu B, Mukherjee P, Newburg DS. Trametes versicolor extract modifies human fecal microbiota composition in vitro. Plant Foods for Human Nutrition 2013;68(2):107-112. doi:10.1007/s11130-013-0342-4
5. Cruz A, Pimentell, L, Rodríguez-­Alcalá LM, Fernandes T, Pintado M. Health benefits of edible mushrooms focused on Coriolus Versicolor: a review. Journal of Food and Nutrition Research 2016;4(12):773-781. doi: 10.12691/jfnr4122
6. Strandwitz P. Neurotransmitter modulation by the gut microbiota. Brain Research 2018;1693(B):128-133. doi.org/10.1016/j.brainres.2018.03.015
7. Carabotti M, Scirocco A, Maselli MA, Severi C. The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Annals of Gastroenterology 2015;28:203-209.
8. Bienenstock J, Kunze W, Forsythe P.  Microbiota and the gut–brain axis. Nutrition Reviews 2015:73(suppl 1):28–31. doi.org/10.1093/nutrit/nuv019
9. Hu X, Wang T, Jin F. Alzheimer’s disease and gut microbiota. Sci China Life Sci 2016;59:1006-1023. doi:10.1007/s11427-016-5083-9
10. Klingelhoefer L & Reichmann H. Pathogenesis of Parkinson disease — the gut–brain axis and environmental factors. Nat Rev Neurol 2015;11:625-636. doi: 10.1038/nrneurol.2015.197
11.  Sampson TR & Mazmanian SK. Control of brain development, function, and behavior by the Microbiome. Cell Host and Microbe 2015;17: 565-576. doi.org/10.1016/j.chom.2015.04.011
12. Ríos-Covián D, Ruas-Madiedo P, Margolles A, Gueimonde M, de los Reyes-Gavilán CG and Salazar N. Intestinal short chain fatty acids and their link with diet and human health. Front Microbiol 2017;7:185. doi: 10.3389/fmicb.2016.00185
13. Flint HJ, Scott KP, Duncan SH et al. (2012) Microbial degradation of complex carbohydrates in the gut. Gut Microbes 2012;3:289-306. doi.org/10.4161/gmic.19897
14. Flint HJ, Duncan SH, Scott KP, Louis P. Conference on ‘Diet, gut microbiology and human health’ Symposium 3: Diet and gut metabolism: linking microbiota to beneficial products of fermentation. Links between diet, gut microbiota composition and gut metabolism. Proceedings of the Nutrition Society 2015;74:13–22. doi.org/10.1017/S0029665114001463
15. den Besten G, van Eunen K, Groen AK, Venema K, Reijngoud D-J, Bakker BM. The role of short-chain fatty acids in the interplay between diet, gut microbiota, and host energy metabolism. Journal of Lipid Research 54;2013:2325-2340. doi 10.1194/jlr.R036012
16. Sun Y & O’Riordan MXD. Regulation of Bacterial Pathogenesis by Intestinal Short-Chain Fatty Acids. Advances in Applied Microbiology 2013;85:93-118.
17. Gibson GR, Hutkins R, Sanders ML, Prescott SL, Reimer RA, Salminen SJ, et al. The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nat Rev Gastroenterol Hepatol 2017;14:491-502.
18. Cruz A, Pimentel L, Fernandes T, Pintado M. Bioactive Properties of Mushroom Coriolus versiolor. Clinical Journal of Mycology Jan 2017;Vol V:15-16.
19. Madureira AR, Amorim M, Gomes AM, Pintado ME, MalcataFX. Protective effect of whey cheese matrix on probiotic strains exposed to simulated gastrointestinal conditions. Food Research Int 2011;44(1):465-470. doi.org/10.1016/j.foodres.2010.09.010
20. Rhoades J, Gibson G, Formentin K, Beer M. and Rastall, R. Inhibition of the 534 adhesion of enteropathogenic Escherichia coli strains to HT-29 cells in culture by chito535 oligosaccharides.Carbohydrate Polymers 2006;64:57-59.
21. Ferrão J, Bell V, Calabrese V, Pimentel L, Pintado M, Fernandes TH. Impact of mushroom nutrition on microbiota and potential for preventative health. Journal of Food and Nutrition Research 2017;5(4):226–233. doi: 10.12691/jfnr-5-4-4