An inflammation is the body's normal response to lesions and infections. The immune system cells move to the site of the injury or infection, and cause an inflammation. To treat this disorder, unspecific small molecule drugs are used, which may cause some side effects.
The inflammation produces mediators such as cytokines, interleukins, and growth factors. It is necessary to regulate the inflammation to stabilize or heal the damaged cells or tissues.
A lot of research is being made, and peptides have been used as an alternative anti-inflammatory therapy. Actually, peptides are considered effective compounds, and show an innovative strategy by stopping, diminishing, and/or changing the expression and activity of mediators.
Small peptide molecules usually have a higher power on their targets, thanks to chemical and biological diversity. For example, some natural therapeutic peptides, as insulin, displayed minor toxicity, and quick disappearance, while others showed good skin penetration.
Right now, treatments are being researched with bioactive peptides used as anti-inflammatory agents.
Therapeutic peptides
Peptides have played a very important role in medicine, since the insulin therapy in the 1920’s. In the United States, more than 60 peptide drugs are on the market, and they keep entering clinical trials and development. So far, peptides have entered clinical studies that include over 150 peptides in active development.
Nowadays, peptides offer an opportunity for therapeutic intervention that closely mimics natural pathways. Most of the peptide drugs are considered as “replacement therapies” that add back or supplement peptide hormones, in cases where endogenous levels are inadequate or absent.
This enthusiasm for these kinds of therapeutics was impacted by some restrictions, like a short half-life (A lot of peptidases, and excretory mechanisms disable and remove peptides), and an insignificant oral bioavailability (The body’s digestive enzymes that break amide bonds of ingested proteins, also break the same bonds in peptide hormones).
Peptides as modulators of inflammatory diseases
The anti-inflammatory peptides kill negative and/or positive bacteria and cancerous cells. Most of the time, the peptides interact with the bacterial surfaces, and insert themselves into the skin. Afterwards, they penetrate the cell and modify the cellular metabolism.
Cancer
Cancer is characterized by abnormal cell growth. It results from defects in the cells, such as eliminating the damaged cells, the formation of new blood vessels, and the ability to invade tissue.
In the treatment, peptides can be used directly as bioactive therapeutics by restraining the tumor growth, and they can also make the passage of drugs easier through the cells and tissue barriers.
Also, peptides have a high efficiency, they can reduce the side-effects, and they have a low production cost. So far, peptides have generated promising results in brain tumor models.
Clinical trials have started, and peptide molecules offer new perspectives of treatment for brain tumors and metastases.
Asthma
Recent studies have shown that hypoallergenic peptides derived from allergens can prevent bronchial hyperreactivity, and also relent and lessen the inflammation in asthmatic airways. Even if the action mechanisms of the peptides are still poorly known, their fast efficiency to cure asthma is looking good.
Arthritis
According to researchers, peptides found in Old World monkeys have a powerful ability to stop rheumatoid arthritis, and collagen protein supplementation has the power to improve the symptoms. These peptides enter the bloodstream, and mount up in the joint cartilage, which lubricates the cartilage. Moreover, collagen enhances skin elasticity, and supports the blood pressure. In addition to this treatment, it has been discovered that patients who consumed a liquid elemental peptide diet for four weeks, saw a significant improvement with the pain. In conclusion, researchers think that a peptide diet may be a solution for patients with symptoms aggravated by foods.
Bowel Inflammation
For the past few years, research has reported that antimicrobial peptides (AMPs) have anti-inflammatory effects. They have the power to inhibit and dampen the release of inflammatory disorder. As a result, these peptides are very appealing to create a treatment. Moreover, Cortistatin, which is a cyclic neuropeptide, has also come out as a possible endogenous anti-inflammatory factor.
Autoimmune diseases
Peptides control a lot of functions in the body, and they have special effects on the immune system. They increase these functions, and improve your health and well-being. This new method of treatment is approved by a lot of medicine practitioners as this therapy aligns perfectly with a medicine approach.
According to researchers, the administration of peptides may stimulate tolerogenic mechanisms, which can hold off or avoid autoimmune diseases. Moreover, the peptide therapy won’t be associated with the side effects of conventional immunosuppression, as it will treat one disease in particular.
Neurological diseases
Research to cure neurological diseases such as Parkinson’s, Huntington’s, Alzheimer’s, amyotrophic lateral sclerosis, are still improving. For Alzheimer’s, a disease that creates intracellular neurofibrillary tangles of hyperphosphorylated tau protein, and extensive neuron death, it has been discovered that peptides are able to inhibit Aβ fibrillization, and reduce Aβ-induced toxicity. There is still some research to do, and peptides are being considered for a treatment.
Emerging peptide areas and technologies
Nature harbors a large variety of natural peptides, which increases the research for therapeutics. In the body, peptides regulate and signal molecules for defense, immunity, stress, growth, and reproduction. For example, in the gut, the microbiome is very interesting because it has a lot of bacteria that could lead to the identification of new peptides from protein fragments, degradation products, or signaling molecules. Ongoing research will create opportunities to treat metabolic diseases.
With time, peptides have also evolved outside the producing organisms. It is now possible to isolate peptides from the skin of frogs and toads. They protect the animal against predators and pathogens. Nowadays, over 3000 antimicrobial peptides have been identified from amphibians, which presents the opportunity for more research and development. Moreover, peptides from venomous animals like spiders and snakes have the ability to counteract disturbances from diverse disorders (as the toxicity from the venom interferes with neural transmission and disrupts critical biochemical signaling networks in the body). It is said that toxic peptides may help cure neurological and cardiovascular diseases, diabetes and cancer.
Recent peptide technologies, including multifunctional peptides, cell penetrating peptides and peptide drug conjugates, will help increase the application of peptides as therapeutics. These new peptide technologies include alternative administration routes beyond the predominantly parental injection route, and conjugates of peptides to antibodies or to small molecules.
The future of peptides
Since the discovery of peptides, it has been proven that they constitute a unique therapeutic niche, and will remain an important player in the pharmaceutical industry. Peptides have evolved with time and science, by engineering new properties and broadening molecular diversity.
With time, researchers will keep finding new opportunities for peptides, which are a natural starting point for drug discovery. In the past five years, regulatory agencies have approved a lot of research completed on peptides, and some very promising peptides are now in late phase clinical trials. Half of them are for infectious diseases, cardiovascular rearmament and oncology.
Also, research keeps expanding the possible range of peptide-based pharmaceuticals to new objectives. Also, improvement in peptide research and biology will continue to support discoveries. After all, an improved knowledge of the molecular basis for human genetic disorders can create new potential therapeutic leads, and increase research efforts to find cures and treatments.
As peptides have a short-life expectancy and can’t be ingested orally, solutions will be researched.
To extend the life expectancy of a peptide, some solutions are being researched, such as containing the enzymatic degradation and using formulations. Those innovative approaches open the way for new methods to deliver peptides.
The peptide oral bioavailability on the therapeutic market is anticipated to show the fastest growth rate in forthcoming years. Indeed, improvements in oral bioavailability and strategies to succeed will fuel the demand for peptide therapeutics in the years to come. In addition, new potential applications for nervous, gastrointestinal, cardiovascular and respiratory disorders, will further increase this demand. Moreover, the research to cure cancer with peptides is anticipated to dominate the market in the next few years as the cancer death rate keeps increasing, as well as research-related activities to treat patients.
In conclusion, it is safe to say that peptides are the future of pharmaceutics. With so many sources found, whether it is on humans or animals, research and discovery are going to keep appearing.
Nowadays, the pharmaceutical peptide pipeline is powerful and steady, with a lot of candidates reaching drug approval status. Moreover, the commercial value of the therapeutic peptide is doing very well on the market. Peptides are really becoming a source of research, and are creating new treatments, and so, the latest emerging approvals promise to extensively extend the market value of peptide therapeutics in the coming years, in the areas of diabetes, oncology and beyond. The market was valued at 22 Billion US$ in 2017, and is now expected to double by 2025.
(Peptide Therapeutics Market Size, Growth)
