Peptides for injury recovery
What are peptides? Why are they important?
Peptides are short chains of amino acids, which are linked together by a type of chemical bond called a peptide bond. Essentially, peptides are small fragments of proteins, ranging from 2 to 50 amino acids in length and having a molecular weight of less than 10 kDa [1]. Despite their diminutive size, peptides play a large role in a variety of physiological processes and are essential for maintaining overall health. From a scientific perspective, studying these molecules may also help elucidate complex biological mechanisms and explain various pathologies; therefore, peptides also represent promising potential drug targets [2].
Peptides play a significant role in many biological processes. Among their many functions, peptides can act as hormones, neurotransmitters, and antimicrobial molecules. Given the central importance of peptides in many biochemical pathways, the dysregulation of bioactive peptide signaling can lead to disease.
Peptides are also important in the pharmaceutical context. Targeting peptide signaling pathways has been a promising strategy for the development of novel therapeutics [3],
and over 40 cyclic peptide drugs are currently in the market. On average, approximately one new cyclopeptide drug enters the market annually [2]. Since the discovery of the insulin peptide in 1921, over 100 bioactive peptides and peptide analogs have been explored for their therapeutic potential [4].
In addition to their therapeutic uses, peptides are also found in many skincare products. They can help reduce inflammation, even out skin tone, and reduce the appearance of wrinkles [5].
Can peptides help injury recovery?
Several studies have reported positive findings after using peptides to treat injuries in animal models. For example, a research team reported that rats treated with OM-LV20, a novel synthetic peptide, demonstrated increased rates of tissue regeneration following skin injury and accelerated rates of spinal cord repair compared to untreated rats [6]. Spinal cord repair was indicated by a larger number of surviving peripheral neurons and improvements in motor function in rats treated with OM-LV20. These findings suggest that OM-LV20 may play a positive role in facilitating tissue healing in rats. Further studies are needed to determine whether these findings can be replicated and generalized to non-model organisms.
There is also evidence suggesting that peptides may play a positive role in tendon repair following injury. For example, a peptide called exendin-4 (Ex-4) appears to boost the proliferation and differentiation of human mesenchymal stem cells (hMSCs) into tenocytes in vitro [7]. Tenocytes are tendon-specific fibroblasts that play a key role in producing connective tissue fibers and regenerating functional tendon tissues following injury. This finding suggests a potential mechanism by which Ex-4 may promote tissue healing following injury.
What are the best peptides for injury recovery? How do they function in injury recovery?
Peptides enhance the healing process following injury by promoting the synthesis of key proteins involved in tissue repair and regulating tissue inflammation. Research suggests that peptides are particularly important in the context of motor neuron and skeletal muscle damage. In such cases, peptides stimulate the synthesis of key proteins involved in nerve and muscle structure and function. As such, peptides help heal “micro-injuries” at the cellular level, leading to overall improvements in muscular endurance and stamina [8].
One peptide sequence that has been implicated in muscle repair is SVVYGLR (SV), a thrombin-cleaved osteopontin-derived motif. Rats treated with local injections of SV demonstrated improved muscle regeneration, diminished fibrosis (a process which generates disorganized scar tissue instead of functional muscle tissue), and improvements in the function of oral and maxillofacial skeletal muscles following damage by severe trauma or surgery [9].
Peptides like ISP and PAP4 have also been shown to promote recovery of motor function in rats following peripheral nerve injury. In one study, ISP and PAP4 were both linked to increased survival of motoneurons, greater numbers of regenerated axons and neuromuscular junctions, reductions in muscle atrophy, and enhanced electrical response of motor units [10].
The synthetic peptide OM-LV20 has also been shown to promote structural and functional recovery of spinal cord injury in adult rats by increasing neuronal survival and regulating oxidative stress [6]. This suggests that peptides may partially influence the healing process through regulating cellular inflammation and oxidative metabolism.
Lastly, the peptide BPC 157 has attracted significant attention for its potential role in tendon, ligament, and muscle healing. BPC 157 is a 15 amino acid fragment of a substance called bodily protection compound (BPC), which has been isolated from human gastric juice and shown to promote various repair processes in vitro [11]. To date, all studies on BPC 157 have been conducted in vitro or using animal models, so it is not possible to assess its effects on injury recovery in humans. Nonetheless, there is evidence that BPC 157 may enhance several cellular processes involved in tissue healing. For example, one study found that treating excised tendons with BPC 157 facilitated increased tendon outgrowth by stimulating the proliferation and migration of tendon-specific fibroblasts [11]. Moreover, BPC 157-treated cells exposed to hydrogen peroxide—an inducer of cellular stress—showed improved robustness and survival compared to cells not treated with BPC 157 [11]. This suggests that BP7 157 may play a role in making cells more resilient to oxidative stress and injury. Another study examined the influence of BPC 157 treatment in rats with hind limb injuries. The authors note increased blood vessel density and improved blood flow to damaged tissue in rats treated with BPC 157, suggesting improved angiogenesis (blood vessel growth) and protection against ischemia [12]. The authors also demonstrated that BPC 157 treatment of hind limb tissue in vitro resulted in upregulation of vascular endothelial growth factor receptor 2 (VEGFR2) [12], a receptor which is necessary for anti-inflammatory immune cells to access areas of damaged tissue and facilitate repair pathways.
It is imperative to note that all of the studies mentioned above were conducted in vitro or using animal models, and therefore the results do not warrant any conclusions about the efficacy of these peptides for human injury recovery.
Sources of peptides
Ways to incorporate peptides
Further studies are needed to determine the efficacy and clinical significance of various peptides in the context of human injury repair. However, considering that peptides are naturally occurring compounds which support a variety of physiological processes, individuals might seek to incorporate peptides into their regimen to support injury recovery or general health. Peptides can be found in a range of dietary sources and supplements, as well as certain topical ointments and creams. Eating a varied diet with sufficient amounts of protein is a good first step, since many peptides are formed from the breakdown of larger protein molecules. Although this may sound simple, eating a healthful and variegated diet is the safest and most accessible way to promote overall health, which will boost your robustness against injury and ability to heal cellular and tissue damage.
Individuals seeking to boost their intake of specific peptides may choose to take commercially available supplements. For example, people wishing to boost joint and muscle strength may take collagen, a peptide which is abundant in connective tissue and tendons. Some evidence suggests that collagen supplementation can support connective tissue recovery and reduce pain following injury [13]. Collagen is also abundant in the skin, and many topical skincare products include collagen in their formulation to promote skin firmness, diminish the appearance of wrinkles, and protect overall skin health [14].
Cod protein is also a rich source of peptides, such as arginine, glycine, taurine, and lysine [15]. These peptides play a role in anti-inflammatory processes, which are important during injury healing to balance inflammation and prevent further damage. In rats, cod protein supplementation was associated with decreases in tissue inflammation and increases in muscle mass following skeletal muscle injury [15].
Some researchers posit that egg white peptides can positively affect wound healing and skin repair. In one study, mice suffering biopsy wounds demonstrated accelerated wound closure and repair of mechanical skin damage when supplemented with dietary egg white peptides [16].
In subjects with acute muscle injuries, peptides derived from autologous plasma may be given via injection to facilitate the healing process. Existing data suggests that injections of autologous platelet-rich plasma (PRP), which contains various endogenous peptides, can speed up the rate of recovery in athletes suffering acute muscle injury [17]. However, it is important to note that this was a small pilot study conducted on a limited group of participants and thus the relevance of this finding remains uncertain. Furthermore, some studies have suggested that the composition of PRP can influence whether it has pro- or anti-inflammatory properties, which determines its ability to promote or inhibit healing in the context of tendon injuries [18].
Conclusion
Peptides are crucial regulators of a variety of biological processes, including tissue healing and injury recovery. Early evidence suggests that some peptides, including OM-LV20, Ex-4, BPC 157, and ISP, may be positively correlated with healing following nerve, muscle, and skin injury. However, most studies to-date have been conducted in vitro or using animal models, and therefore researchers and public figures should be cautious when making claims about the potential benefits of peptides for human injury recovery. Further clinical studies will be imperative to determine the safety, efficacy, and potential side-effects of various peptides in the context of injury recovery. Considering the profitability of the supplement industry, it is worth approaching companies’ claims about peptides and other nutritional compounds with an appropriate degree of skepticism. As always, it is best to discuss any specific health concerns with your doctor before making major changes to your diet or supplement regime.