Local Probiotic Therapy with Lactobacillus plantarum Mitigates Scar Formation in Rabbits after Burn Injury and Infection

Probiotics in Dermatology: An Evidence-based Approach

Probiotics are viable microorganisms that confer health benefits when administered to the host in adequate amounts. Over the past decade, there has been a growing demand for the use of oral and topical probiotics in several inflammatory conditions such as atopic dermatitis, psoriasis, acne vulgaris, etc., although their role in a few areas still remains controversial. The objective of this article is to shed light on understanding the origin and implications of microbiota in the pathophysiology of these dermatological conditions and the effect of probiotic usage. We have conducted a comprehensive search of the literature across multiple databases (PubMed, EMBASE, MEDLINE, and Google Scholar) on the role of probiotics in dermatological disorders. Commensal microbes of the skin and gastrointestinal tract play an important role in both health and disease. Increased use of probiotics has asserted a good safety profile, especially in this era of antibiotic resistance. With the advent of new products in the market, the indications, mechanism of action, efficacy, and safety profile of these agents need to be validated. Further studies are required. Oral and topical probiotics may be tried as a treatment or prevention modality in cutaneous inflammatory disorders, thus facilitating decreased requirement for topical or systemic steroids and antimicrobial agents. Tempering microbiota with probiotics is a safe and well-tolerated approach in this era of antimicrobial resistance.

Carbon source competition within the wound microenvironment can significantly influence infection progression

It is becoming increasingly apparent that commensal skin bacteria have an important role in wound healing and infection progression. However, the precise mechanisms underpinning many of these probiotic interactions remain to be fully uncovered. In this work, we demonstrate that the common skin commensal Cutibacterium acnes can limit the pathogenicity of the prevalent wound pathogen Pseudomonas aeruginosa in vivo. We show that this impact on pathogenicity is independent of any effect on growth, but occurs through a significant downregulation of the Type Three Secretion System (T3SS), the primary toxin secretion system utilised by P. aeruginosa in eukaryotic infection. We also show a downregulation in glucose acquisition systems, a known regulator of the T3SS, suggesting that glucose availability in a wound can influence infection progression. C. acnes is well known as a glucose fermenting organism, and we demonstrate that topically supplementing a wound with glucose reverses the probiotic effects of C. acnes. This suggests that introducing carbon source competition within the wound microenvironment may be an effective way to prevent or limit wound infection.

Technologies used in the treatment of burn victims in intensive care: a scope review

OBJECTIVES

to analyze the technologies used by the nursing team in the treatment of skin lesions caused by burns in patients under intensive care.

METHODS

this is a scope review conducted on the LILACS, Medline, PubMed, and CINAHL databases without temporal or language restrictions.

RESULTS

the highlighted technologies included the use of specialized dressings, biological agents such as probiotics and cyanobacteria, as well as negative pressure therapies and enzymes such as papain and collagenase. Some technologies, such as nanocrystalline silver, demonstrated efficacy in infection control.

FINAL CONSIDERATIONS

the study identified essential technologies in burn care, emphasizing the need for further research on "soft" technologies. The findings support the promotion of evidence-based nursing care for burn patients in intensive care and enhance knowledge about effective treatments.

The role of the skin microbiome in wound healing

The efficient management of skin wounds for rapid and scarless healing represents a major clinical unmet need. Nonhealing skin wounds and undesired scar formation impair quality of life and result in high healthcare expenditure worldwide. The skin-colonizing microbiota contributes to maintaining an intact skin barrier in homeostasis, but it also participates in the pathogenesis of many skin disorders, including aberrant wound healing, in many respects. This review focuses on the composition of the skin microbiome in cutaneous wounds of different types (i.e. acute and chronic) and with different outcomes (i.e. nonhealing and hypertrophic scarring), mainly based on next-generation sequencing analyses; furthermore, we discuss the mechanistic insights into host-microbe and microbe-microbe interactions during wound healing. Finally, we highlight potential therapeutic strategies that target the skin microbiome to improve healing outcomes.

Living, quiescent Lactobacillus plantarum Lp90 probiotic, delivered topically to full thickness tissues in vitro via a just-add-water cream delivery system, stimulates the expression of elastin protein

INTRODUCTION

Delivering living probiotics to the skin can be challenging as most water-containing cosmetic products require preservatives to maintain product stability. A recently introduced powdered technology [Stratabiosys™, Vantage Personal Care] allows for quiescent probiotic powders to be stored for extended periods of time. The powders can then be reconstituted to creams at the point of use by adding water and mixing and were examined in vitro on reconstructed human full thickness tissues to see if the probiotic had any influence of several important biomolecules expressed in the skin.

MATERIALS AND METHODS

A probiotic powder containing 200 M CFU/gram of living quiescent Lactobacillus plantarum Lp90 was reconstituted to a cream by adding ultrapure water and gently mixing the components at room temperature to quickly produce a cream. The resulting cream was tested topically on Epiderm® Full Thickness Tissues by treating the tissues for 24 h, removing the cream with a PBS rinse and then repeating the treatment for another 24 h. The resulting tissues were examined for four strategically important skin biomolecules including Type 1A collagen, elastin, filaggrin and hyaluronic acid. The probiotic-containing powder was tested against untreated tissues and powders not containing probiotics and powders containing measured amounts of one of two cryoprotectants known to be used to maintain the integrity of the quiescent probiotics during drying of the quiescent probiotic powders.

RESULTS

It was found that topical treatment on Epiderm® tissues with creams containing 2 M (1%), 4 M (2%) and 6 M (3%) CFU/gram prepared from a base powder containing 200 M CFU/gram of Lactobacillus plantarum Lp90 stimulated elastin expression in a dose dependent fashion. There was no effect on the other biomolecules examined in the studies. In addition, it was found that creams made from powders containing only the known cryoprotectants, not bacteria, had no influence on elastin expression.

CONCLUSION

The results of this study demonstrate that topical delivery of probiotics is possible from powders containing quiescent probiotic powders converted to creams just prior to application to the tissues. In the case of a powder containing Lactobacillus plantarum Lp90, topical application significantly increased expression of elastin in the skin replicants after 48 h of exposure to the cream made with the probiotic. The elastin-stimulating effects are not coming from the oligosaccharide cryoprotectants used to maintain the probiotic powders in their quiescent, dried state. The results indicate that it is the living Lactobacillus plantarum probiotic that is stimulating the elastin expression in the skin tissues.

Looking for the Ideal Probiotic Healing Regime

Wound healing is a multi-factorial response to tissue injury, aiming to restore tissue continuity. Numerous recent experimental and clinical studies clearly indicate that probiotics are applied topically to promote the wound-healing process. However, the precise mechanism by which they contribute to healing is not yet clear. Each strain appears to exert a distinctive, even multi-factorial action on different phases of the healing process. Given that a multi-probiotic formula exerts better results than a single strain, the pharmaceutical industry has embarked on a race for the production of a formulation containing a combination of probiotics capable of playing a role in all the phases of the healing process. Hence, the object of this review is to describe what is known to date of the distinctive mechanisms of each of the most studied probiotic strains in order to further facilitate research toward the development of combinations of strains and doses, covering the whole spectrum of healing. Eleven probiotic species have been analyzed, the only criterion of inclusion being a minimum of two published research articles.

Photodynamic Therapy, Probiotics, Acetic Acid, and Essential Oil in the Treatment of Chronic Wounds Infected with Pseudomonas aeruginosa

As a prevalent medical problem that burdens millions of patients across the world, chronic wounds pose a challenge to the healthcare system. These wounds, often existing as a comorbidity, are vulnerable to infections. Consequently, infections hinder the healing process and complicate clinical management and treatment. While antibiotic drugs remain a popular treatment for infected chronic wounds, the recent rise of antibiotic-resistant strains has hastened the need for alternative treatments. Future impacts of chronic wounds are likely to increase with aging populations and growing obesity rates. With the need for more effective novel treatments, promising research into various wound therapies has seen an increased demand. This review summarizes photodynamic therapy, probiotics, acetic acid, and essential oil studies as developing antibiotic-free treatments for chronic wounds infected with Pseudomonas aeruginosa. Clinicians may find this review informative by gaining a better understanding of the state of current research into various antibiotic-free treatments. Furthermore. this review provides clinical significance, as clinicians may seek to implement photodynamic therapy, probiotics, acetic acid, or essential oils into their own practice.

Using the Galleria mellonella burn wound and infection model to identify and characterize potential wound probiotics

Burn wound infection is the leading cause of mortality among burn wound patients. One of the most commonly isolated bacterial burn wound pathogens is Pseudomonas aeruginosa, a notorious nosocomial multidrug-resistant pathogen. As a consequence of its recalcitrance to frontline antibiotic therapy, there is an urgent need to develop alternative treatment avenues to tackle this pathogen. One potential alternative infection prevention measure is to seed the wound bed with probiotic bacteria. Several species of Lactobacillus, a common commensal bacterium, have been previously reported to display growth inhibition activity against wound pathogens. Various species of this genus have also been shown to augment the wound healing process, which makes it a promising potential therapeutic agent. Due to the complexity of the burn wound trauma and burn wound infection, an in vivo model is required for the development of novel therapeutics. There are multiple in vivo models that are currently available, the most common among them being the murine model. However, mammalian burn wound infection models are logistically challenging, do not lend themselves to screening approaches and come with significant concerns around ethics and animal welfare. Recently, an invertebrate burn wound and infection model using G. mellonella has been established. This model addresses several of the challenges of more advanced animal models, such as affordability, maintenance and reduced ethical concerns. This study validates the capacity of this model to screen for potential wound probiotics by demonstrating that a variety of Lactobacillus spp. can limit P. aeruginosa burn wound infection and improve survival.

The effect of probiotic supplementation on episiotomy wound healing among primiparous women: a triple-blind randomized clinical trial

BACKGROUND

Probiotics increase the defense power of immune system and accelerate the wound healing process by anti-inflammatory mechanisms at the wound site. The present study aimed at evaluating the effect of Lactobacillus casei oral supplementation on episiotomy wound healing among primiparous women.

METHODS

This triple-blind randomized clinical trial was performed on 74 primiparous women delivered in Alzahra Hospital, Tabriz, Iran. Participants with mediolateral episiotomy (incision length equal to and less than 5 cm) were randomly assigned to the probiotic and placebo groups. The probiotic group received Lactobacillus casei 431 with 1.5 * 10⁹ colony-forming unit /capsule once a day from the day after birth to 14 days. Wound healing as a primary outcome was measured by Redness, Edema, Ecchymosis, Discharge, Approximation and pain as a secondary outcome by the Visual Analogue Scale before discharge, 5 ± 1 and 15 ± 1 days after birth. The data were analyzed using independent t-test and repeated measures one way analysis of variance.

RESULTS

The mean (standard deviation: SD) score of wound healing in the probiotic group altered from 4.91(1.86) before discharge to 1.55 (0.99) during 5 ± 1 days after birth and reached to 0.95 (0.27) during 15 ± 1 days after birth. Further, the mean (SD) score of wound healing in the placebo group altered from 4.62 (1.99) before discharge to 2.80 (1.20) during 5 ± 1 days after birth and reached to 1.45(0.71) during 15 ± 1 days after birth (adjusted mean difference: -0.50, confidence interval 95%: -0.96 to -0.05, P = 0.03).

CONCLUSION

Lactobacillus casei oral supplementation is effective in healing episiotomy wounds. It is suggested to evaluate the effect of topical use of Lactobacillus casei on episiotomy repair and pain in further studies.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials (IRCT): IRCT20170506033834N7. Date of registration: 11/08/2021.

The role of probiotics as wound healers: an overall view

A wound is an injury to the skin or damage to the body tissue. The healing process differs between various kinds of wounds. Treatment of hard-to-heal (chronic) wounds becomes challenging for healthcare practitioners, especially if patients have underlying health complications such as diabetes. Infection of wounds is another factor that interferes with the healing process and extends its duration. Active research is being conducted into the development of advanced wound dressing technologies. These wound dressings are intended to manage the exudate, reduce bacterial infection and speed up the healing process. Probiotics have been receiving much attention because of their potential application in the clinical field, especially in diagnostics and treatment strategies of various infectious and non-infectious diseases. The host immune-modulatory response and antimicrobial activity of probiotics are expanding their role in the development of improved wound dressing technology.

Improved infectious burn wound healing by applying lyophilized particles containing probiotics and prebiotics

Lactiplantibacillus plantarum cells were encapsulated in a mixture of cationic and anionic polymers, with the final composition stabilized through freeze-drying. A D-optimal design was used to examine the effects of different polymer concentrations as well as adding prebiotics on the probiotic viability and swelling behavior of the formulations. Scanning electron micrographs revealed stacked particles capable of rapidly absorbing significant amounts of water. These images corresponded to initial swelling percentages of around 2000% for the optimal formulation. The optimized formula had a viability percentage of more than 82%, with the stability studies suggesting that the powders should be stored at refrigerated temperatures. The physical characteristics of the optimized formula were examined to ensure compatibility with its application. According to antimicrobial evaluations, the difference in pathogen inhibition between formulated and fresh probiotics was less than a logarithm. The final formula was tested in vivo and showed improved wound healing indicators. The optimized formula resulted in a higher rate of wound closure and infection clearance. Furthermore, the molecular studies for oxidative stress indicated that the formula could modify wound inflammatory responses. In histological investigations, the probiotic-loaded particles functioned exactly as efficaciously as silver sulfadiazine ointment did.

Role of wound microbiome, strategies of microbiota delivery system and clinical management

Delayed wound healing is one of the most global public health threats affecting nearly 100 million people each year, particularly the chronic wounds. Many confounding factors such as aging, diabetic disease, medication, peripheral neuropathy, immunocompromises or arterial and venous insufficiency hyperglycaemia are considered to inhibit wound healing. Therapeutic approaches for slow wound healing include anti-infection, debridement and the use of various wound dressings. However, the current clinical outcomes are still unsatisfied. In this review, we discuss the role of skin and wound commensal microbiota in the different healing stages, including inflammation, cell proliferation, re-epithelialization and remodelling phase, followed by multiple immune cell responses to commensal microbiota. Current clinical management in treating surgical wounds and chronic wounds was also reviewed together with potential controlled delivery systems which may be utilized in the future for the topical administration of probiotics and microbiomes. This review aims to introduce advances, novel strategies, and pioneer ideas in regulating the wound microbiome and the design of controlled delivery systems.

The Antimicrobial Effect of Various Single-Strain and Multi-Strain Probiotics, Dietary Supplements or Other Beneficial Microbes against Common Clinical Wound Pathogens

The skin is the largest organ in the human body and is colonized by a diverse microbiota that works in harmony to protect the skin. However, when skin damage occurs, the skin microbiota is also disrupted, and pathogens can invade the wound and cause infection. Probiotics or other beneficial microbes and their metabolites are one possible alternative treatment for combating skin pathogens via their antimicrobial effectiveness. The objective of our study was to evaluate the antimicrobial effect of seven multi-strain dietary supplements and eleven single-strain microbes that contain probiotics against 15 clinical wound pathogens using the agar spot assay, co-culturing assay, and agar well diffusion assay. We also conducted genera-specific and species-specific molecular methods to detect the DNA in the dietary supplements and single-strain beneficial microbes. We found that the multi-strain dietary supplements exhibited a statistically significant higher antagonistic effect against the challenge wound pathogens than the single-strain microbes and that lactobacilli-containing dietary supplements and single-strain microbes were significantly more efficient than the selected propionibacteria and bacilli. Differences in results between methods were also observed, possibly due to different mechanisms of action. Individual pathogens were susceptible to different dietary supplements or single-strain microbes. Perhaps an individual approach such as a 'probiogram' could be a possibility in the future as a method to find the most efficient targeted probiotic strains, cell-free supernatants, or neutralized cell-free supernatants that have the highest antagonistic effect against individual clinical wound pathogens.

Efficacy of probiotic Streptococcus thermophilus in counteracting TGF-β1-induced fibrotic response in normal human dermal fibroblasts

BACKGROUND

Abnormal and deregulated skin wound healing associated with prolonged inflammation may result in dermal fibrosis. Since the current therapeutic strategies revealed unsatisfactory, the investigation of alternative approaches such as those based on the use of specific probiotic strains could provide promising therapeutic options. In this study, we aimed to evaluate whether the lysate from S. thermophilus could antagonize the fibrogenic effects of TGF-β1 in normal human dermal fibroblasts (NHDF).

METHODS

NHDF were exposed to TGF-β1 to establish a fibrotic phenotype. Proliferation rate and cell number were measured using the IncuCyte® Live Cell Imager system and the trypan blue dye exclusion test. Phenoconversion markers (α-SMA and fibronectin) and collagen I levels were assessed by western blot and immunofluorescence. The mRNA levels of TGF-β1 were evaluated by RT-PCR. The Smad2/3 phosphorylation level as well as β-catenin and PPARγ expression, were assessed by western blot. The cell contractility function and migration of NHDF were studied using collagen gel retraction assay, and scratch wound healing assay, respectively. The effects of S. thermophilus lysate, alone or combined with TGF-β1, were evaluated on all of the above-listed parameters and markers associated with TGF-β1-induced fibrotic phenotype.

RESULTS

Exposure to the S. thermophilus lysate significantly reduced the key mediators and events involved in the abnormal activation of myofibroblasts by TGF-β1 within the fibrotic profile. The S. thermophilus treatment significantly reduced cell proliferation, migration, and myo-differentiation. In addition, the treatment with probiotic lysate reduced the α-SMA, fibronectin, collagen-I expression levels, and affected the collagen contraction ability of activated dermal fibroblasts. Moreover, the probiotic targeted the TGF-β1 signaling, reducing Smad2/3 activation, TGF-β1 mRNA level, and β-catenin expression through the upregulation of PPARγ.

CONCLUSION

This is the first report showing that S. thermophilus lysate had a remarkable anti-fibrotic effect in TGF-β1-activated NHDF by inhibiting Smad signaling. Notably, the probiotic was able to reduce β-catenin and increase PPARγ levels. The findings support our point that S. thermophilus may help prevent or treat hypertrophic scarring and keloids.

Lactic acid bacteria: prominent player in the fight against human pathogens

INTRODUCTION

The human microbiome is a unique repository of diverse bacteria. Over 1000 microbial species reside in the human gut, which predominantly influences the host's internal environment and plays a significant role in host health. Lactic acid bacteria have long been employed for multiple purposes, ranging from food to medicines. Lactobacilli, which are often used in commercial food fermentation, have improved to the point that they might be helpful in medical applications.

AREAS COVERED

This review summarises various clinical and experimental evidence on efficacy of lactobacilli in treating a wide range of infections. Both laboratory based and clinical studies have been discussed.

EXPERT OPINION

Lactobacilli are widely accepted as safe biological treatments and host immune modulators (GRAS- Generally regarded as safe) by the US Food and Drug Administration and Qualified Presumption of Safety. Understanding the molecular mechanisms of lactobacilli in the treatment and pathogenicity of bacterial infections can help with the prediction and development of innovative therapeutics aimed at pathogens which have gained resistance to antimicrobials. To formulate effective lactobacilli based therapy significant research on the effectiveness of different lactobacilli strains and its association with demographic distribution is required. Also, the side effects of such therapy needs to be evaluated.

The Probiotic Strains Bifidοbacterium lactis, Lactobacillus acidophilus, Lactiplantibacillus plantarum and Saccharomyces boulardii Regulate Wound Healing and Chemokine Responses in Human Intestinal Subepithelial Myofibroblasts

Bifidobacterium lactis, Lactobacillus acidophilus, Lactiplantibacillus plantarum and Saccharomyces boulardii are common probiotic supplements. Colonic subepithelial myofibroblasts (cSEMFs) are actively involved in mucosal wound healing and inflammation. cSEMFs, isolated from healthy individuals, were stimulated with 102 or 104 cfu/mL of these probiotic strains alone and in combination, and their effect on chemokine and wound healing factor expression was assessed by qRT-PCR, ELISA and Sircol Assay, and on cSEMFs migration, by Wound Healing Assay. These strains remained viable and altered cSEMFs’ inflammatory and wound healing behavior, depending on the strain and concentration. cSEMFs treated with a combination of the four probiotics had a moderate, but statistically significant, increase in the mRNA and/or protein expression of chemokines CXCL1, CXCL2, CXCL4, CXCL8, CXCL10, CCL2 and CCL5, and healing factors, collagen type I and III, fibronectin and tissue factor. In contrast, when each strain was administered alone, different effects were observed, with greater increase or decrease in chemokine and healing factor expression, which was balanced by the mixture. Overall, this study highlights that the use of multiple probiotic strains can potentially alert the gut mucosal immune system and promote wound healing, having a better effect on mucosal immunity than the use of single probiotics.

Heat-killed probiotic Lactobacillus plantarum affects the function of neutrophils but does not improve survival in murine burn injury

Probiotics have become of interest as therapeutics in trauma or sepsis-induced inflammation due to their ability to affects the immune response. However, their use is still under debate due to the potential risk of septicemia. Therefore, heat-killed probiotics offer a potential alternative, with recent research suggesting a comparable immunomodulating potential and increased safety. In a previous study, we demonstrated decreased mortality by administration of live Lactobacillus plantarum in a mouse burn-sepsis model. Neutrophils are an essential innate defense against pathogens. Therefore, our present study aims to understand the impact of heat-killed probiotic L. plantarum (HKLP) on neutrophil function. Utilizing an in vitro stimulation with HKLP and a burn-infection in vivo model, we determined that administration of HKLP induced significant release of granulocyte-colony stimulating factor (G-CSF) and stimulated the release of pro-and anti-inflammatory cytokines. HKLP had no impact on neutrophil function, such as phagocytosis, oxidative burst, and NETosis, but increased apoptosis and activated neutrophils. HKLP did not improve survival. Together, contrary to our hypothesis, heat-killed probiotics did not improve neutrophil function and survival outcome in a murine severe burn injury model.

Challenges and innovations in treating chronic and acute wound infections: from basic science to clinical practice

Acute and chronic wound infection has become a major worldwide healthcare burden leading to significantly high morbidity and mortality. The underlying mechanism of infections has been widely investigated by scientist, while standard wound management is routinely been used in general practice. However, strategies for the diagnosis and treatment of wound infections remain a great challenge due to the occurrence of biofilm colonization, delayed healing and drug resistance. In the present review, we summarize the common microorganisms found in acute and chronic wound infections and discuss the challenges from the aspects of clinical diagnosis, non-surgical methods and surgical methods. Moreover, we highlight emerging innovations in the development of antimicrobial peptides, phages, controlled drug delivery, wound dressing materials and herbal medicine, and find that sensitive diagnostics, combined treatment and skin microbiome regulation could be future directions in the treatment of wound infection.

The 3-D configuration of excisional skin wound healing after topical probiotic application

Nowadays, there is an increasing knowledge that probiotic bacteria, topically applied, affects skin pathology. The objective of this study is to evaluate the effect on wound healing of locally applied probiotics by calculating the 3-D configuration of a standardized excisional wound. Fifty-two male Wistar rats were randomly allocated into groups: control, PRO1 [L. plantarum] and PRO2 [L. rhamnosus, B. longum]. Six excisional full-thickness wounds were created on each dorsum by an 8-mm circular biopsy punch; probiotics or saline were applied on days 0, 2, 4, 8, 16, photos of the wounds taken and specimens excised for histology [4 rats/group/time-point]. Both probiotic-groups exhibited accelerated healing significantly faster than the control, throughout, PRO2 exhibiting finally the best results [day 16]. However, only on day 2, did PRO1 exhibit the best results [wounded area, borders distance and epitheliazation line]. The results clearly demonstrate that the topical application of probiotics significantly improves the healing process, each strain working differently and more effectively in different healing phases. Thus, a combined formula containing different probiotics to modulate various healing phases is desirable. To this end our research continous.

Large animal models of thermal injury

Burn injury results in a triad of inter-related adaptive responses: a systemic inflammatory response, a stress response, and a consequent hypermetabolic state which supports the former two. These pathological responses extend beyond the site of injury to affect distant organs and influence long-term outcomes in the patient. Animal models have proven valuable in advancing our understanding of mechanisms underlying the multifactorial manifestations of burn injury. While rodent models have been unprecedented in providing insights into signaling pathways, metabolic responses, protein turnover, cellular and molecular changes; small animal models do not replicate hypermetabolism, hyperinflammation, and wound healing after a burn injury as seen in humans. Herein, we provide a concise review of preferred large animal models utilized to understand burn pathophysiology based on organ systems and associated dysfunction. Additionally, we present a detailed protocol of contact burn injury in the Yorkshire pig model with a focus on preoperative care, anesthesia, analgesia, wound excision and grafting, dressing application, and frequency of dressing changes.

Insight Into the Beneficial Role of Lactiplantibacillus plantarum Supernatant Against Bacterial Infections, Oxidative Stress, and Wound Healing in A549 Cells and BALB/c Mice

Lactiplantibacillus plantarum MTCC 2621 is a well-characterized probiotic strain and is reported to possess many health benefits. However, the wound healing potential of this probiotic is yet to be explored. Here, we have assessed the antibacterial, antioxidant, and wound healing activities of cell-free supernatant of Lactiplantibacillus plantarum MTCC 2621 (Lp2621). Lp2621 exhibited excellent antibacterial activity against the indicator bacteria in the agar well diffusion assay. Lp2621 did not show any hemolytic activity. The safety of Lp2621 gel was established using the skin irritation assay in BALB/c mice, and no dermal reactions were observed. The supernatant showed 60–100% protection of A549 cells against H₂O₂-induced stress. In the scratch assay, Lp2621 accelerated wound healing after 24 h of treatment. The percent wound healing was significantly higher in cells treated with Lp2621 at 18–24 h posttreatment. In an excision wound healing in mice, topical application of Lp2621 gel showed faster healing than the vehicle- and betadine-treated groups. Similar wound healing activity was observed in wounds infected with Staphylococcus aureus. Histological examination revealed better wound healing in Lp2621-treated mice. Topical treatment of the wounds with Lp2621 gel resulted in the upregulation of pro-inflammatory cytokine IL-6 in the early phase of wound healing and enhanced IL-10 expression in the later phase. These findings unveil a protective role of Lp2621 against bacterial infection, oxidative stress, and wound healing.

Avoidance of milk and dairy products after oral surgery-is such a recommendation still valid? A cross-sectional study among German and international oral and maxillofacial surgeons and dental practitioners with review of the literature

PURPOSE

For prevention of wound-healing complications, patients in German-speaking countries are traditionally advised to avoid consumption of milk and dairy products after oral surgery. In the absence of national and international guidelines, this study investigates scientific evidence and compares international practice, frequency scale, and rationale behind such recommendation.

METHODS

Comparison of a German cross-sectional mono-center-questionnaire pilot study and a survey among international oral and maxillofacial surgeons (OMFS), specialized oral surgeons and general dentists, evaluating international practice regarding post-operative dietary and nutrition recommendations. Our literature review further assessed scientific evidence for relevant effects of probiotics, prebiotics, and/or synbiotics.

RESULTS

Among German study participants, 56% (n = 64/114) advise patients to avoid milk and dairy products, with 42% of OMFS (n = 38) and 65% (n = 76) of the general dentists recommending abstention (p = .027). In striking contrast, such recommendation could not be identified in our international survey (n = 143) (t test, p < .001) nor in the literature. There were significant differences between German and international study participants regarding the rationale for dietary recommendations, with dental schools and literature most frequently indicated as sources (Fisher's exact test, p < .001).

CONCLUSION

The hypothesis of a harmful effect of the consumption of milk and dairy products after dentoalveolar surgery could not be supported by evidence. The recommendation to avoid dairy products post-surgery was identified as a specific phenomenon practiced almost exclusively in German-speaking countries. Corresponding recommendations, most probably based on a now irrelevant risk of contracting tuberculosis from milk products, can at present no longer be substantiated.

Microbiome Modulation as a Therapeutic Approach in Chronic Skin Diseases

There is a growing quantity of evidence on how skin and gut microbiome composition impacts the course of various dermatological diseases. The strategies involving the modulation of bacterial composition are increasingly in the focus of research attention. The aim of the present review was to analyze the literature available in PubMed (MEDLINE) and EMBASE databases on the topic of microbiome modulation in skin diseases. The effects and possible mechanisms of action of probiotics, prebiotics and synbiotics in dermatological conditions including atopic dermatitis (AD), psoriasis, chronic ulcers, seborrheic dermatitis, burns and acne were analyzed. Due to the very limited number of studies available regarding the topic of microbiome modulation in all skin diseases except for AD, the authors decided to also include case reports and original studies concerning oral administration and topical application of the pro-, pre- and synbiotics in the final analysis. The evaluated studies mostly reported significant health benefits to the patients or show promising results in animal or ex vivo studies. However, due to a limited amount of research and unambiguous results, the topic of microbiome modulation as a therapeutic approach in skin diseases still warrants further investigation.

Effects of Probiotics in the Management of Infected Chronic Wounds: From Cell Culture to Human Studies

BACKGROUND

Chronic wounds are commonly associated with polymicrobial biofilm infections. In the last years, the extensive use of antibiotics has generated several antibiotic-resistant variants. To overcome this issue, alternative natural treatments have been proposed, including the use of microorganisms like probiotics. The aim of this manuscript was to review current literature concerning the application of probiotics for the treatment of infected chronic wounds.

METHODS

Relevant articles were searched in the Medline database using PubMed and Scholar, using the keywords "probiotics" and "wound" and "injuries", "probiotics" and "wound" and "ulcer", "biofilm" and "probiotics" and "wound", "biofilm" and "ulcer" and "probiotics", "biofilm" and "ulcer" and "probiotics", "probiotics" and "wound".

RESULTS

The research initially included 253 articles. After removal of duplicate studies, and selection according to specific inclusion and exclusion criteria, 19 research articles were included and reviewed, accounting for 12 in vitro, 8 in vivo studies and 2 human studies (three articles dealing with animal experiments included also in vitro testing). Most of the published studies about the effects of probiotics for the treatment of infected chronic wounds reported a partial inhibition of microbial growth, biofilm formation and quorum sensing.

DISCUSSION

The application of probiotics represents an intriguing option in the treatment of infected chronic wounds with multidrug-resistant bacteria; however, current results are difficult to compare due to the heterogeneity in methodology, laboratory techniques, and applied clinical protocols. Lactobacillus plantarum currently represents the most studied strain, showing a positive application in burns compared to guideline treatments, and an additional mean in chronic wound infections.

CONCLUSIONS

Although preliminary evidence supports the use of specific strains of probiotics in certain clinical settings such as infected chronic wounds, large, long-term clinical trials are still lacking, and further research is needed.

Topical Delivery of Lactobacillus Culture Supernatant Increases Survival and Wound Resolution in Traumatic Acinetobacter baumannii Infections

Species of Lactobacillus have been proposed as potential candidates for treating wound infections due to their ability to lower pH, decrease inflammation, and release antimicrobial compounds. This study investigated the impact of lactobacilli (Lactobacillus acidophilus ATCC 4356, Lactobacillus casei ATCC 393, Lactobacillus reuteri ATCC 23272) secreted products on wound pathogens in vitro and in a murine wound infection model. Evaluation of 1-5 day lactobacilli conditioned media (CM) revealed maximal inhibition against wound pathogens using the 5-day CM. The minimum inhibitory concentration (MIC) of 5-day Lactobacillus CMs was tested by diluting CM in Mueller-Hinton (MH) broth from 0 to 25% and was found to be 12.5% for A. baumannii. Concentrating the CM to 10× with a 3 kDa centrifuge filter decreased the CM MIC to 6.25-12.5% for A. baumannii planktonic cells. Minimal impact of 5-day CMs was observed against bacterial biofilms. No toxicity was observed when these Lactobacillus CMs were injected into Galleria melonella waxworms. For the murine A. baumannii wound infection studies, improved survival was observed following topical treatment with L. acidophilus ATCC 4356 or L. reuteri ATCC 23272, while L. reuteri ATCC 23272 treatment alone improved wound resolution. Overall, this study suggests that the topical application of certain Lactobacillus species byproducts could be effective against gram-negative multi-drug resistant (MDR) wound pathogens, such as A. baumannii.

Enterococcus faecium L-15 Extract Enhances the Self-Renewal and Proliferation of Mouse Skin-Derived Precursor Cells

Lactic acid bacteria (LAB) in the gastrointestinal tract have beneficial health effects. LAB activate the proliferation of intestinal stem cells and speed the recovery of damaged intestinal cells, but little is known about effect of LAB on other adult stem cells. In this study, a cell-free extract of Enterococcus faecium L-15 (L15) was exposed to mouse skin-derived precursor cells (SKPs), and the changes in characteristics associated with proliferation and self-renewal capacity were investigated. L15 increased the size of the spheres and the proliferation rate of SKPs. Cell cycle analysis revealed that cells in the S-phase increased after treatment with L15. In the L15-treated group, the total number of spheres significantly increased. The expression level of pluripotency marker genes also increased, while the mesenchymal lineage-related differentiation marker genes significantly decreased in the L15-treated group. The PI3K/Akt signaling pathway was activated by L15 in SKPs. These results indicate that L15 enhances proliferation and self-renewal of SKPs and may be used as a supplement for stem cell maintenance or application of stem cell therapy. This is the first report to investigate the functional effects of E. faecium on the proliferation and self-renewal capacity of SKPs.

Lactobacillus bulgaricus and Lactobacillus plantarum improve diabetic wound healing through modulating inflammatory factors

Probiotics are nonpathogenic bacterial strains that exert beneficial effects on the host. Previous studies have shown that topical use of some strains of probiotic bacteria have good effects on the healing of cutaneous wounds. In the current study, the wound healing potentials of bacterial probiotics on diabetic cutaneous wounds were evaluated. The effects of probiotics on migration, the viability of fibroblasts, and macrophage proliferation were measured through using wound healing assay, methylthiazol tetrazolium assay, and bromodeoxyuridine, respectively. In this regard, in vivo diabetic wound healing experiments in Wistar rats following treatment with nontoxic concentrations of Lactobacillus bulgaricus and Lactobacillus plantarum were conducted. The histopathological and gene expression analyses were performed following removal of wound sites 3, 7, and 14 days postwounding. Results showed that treatment with probiotics accelerated the healing process of diabetic wounds and modulated the inflammatory cells in wound sites during a 14-day period postwounding. The altered mRNA levels of inflammatory cytokines were observed in wound sites following treatment with probiotics. The findings of the current study reveal that L. bulgaricus and L. plantarum could improve the healing of diabetic wounds via regulation of inflammation.

The role of topical probiotics on wound healing: A review of animal and human studies

Pathogenic, opportunistic, and commensal bacterial coexist in the intestinal tract, and imbalances among these strains have been linked to systemic inflammation and a variety of disease states. Similarly, human skin plays an important role as an interface between the body and the environment with an estimated 1 billion microbes per square centimetres. Skin microbiome fluctuations that cause increases in pathologic bacteria, either because of individual and/or environmental factors, can lead to disease states at the skin level ranging from inflammatory conditions to infections. As wounds are inherently associated with perturbations in the local microflora due to injury and activation of the immune responses, the addition of topical probiotics could be a means to prevent infection, regulate inflammation, and potentially augment healing. The goal of this review is to analyse the impact the skin microbiome has on cutaneous wound healing with a focus on developing proposed treatment algorithms and support for their therapeutic potential.

Cell-free supernatant of Streptococcus salivarius M18 impairs the pathogenic properties of Pseudomonas aeruginosa and Klebsiella pneumonia

M18 strain of Streptococcus salivarius is a bacterial replacement probiotic that has been suggested for use in the oral cavity. Here, we have shown that S. salivarius M18 cell-free supernatant reduced the growth of the two most common human pathogens Pseudomonas aeruginosa and Klebsiella pneumonia and sensitized the pathogenic bacteria to antibiotic. Besides, the supernatant inhibited biofilm formation of P. aeruginosa drastically. For pinpointing the biomolecular changes that occurred in P. aeruginosa incubated with the probiotic supernatant, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was used. Unsupervised learning algorithms, principal component analysis (PCA) and hierarchical cluster analysis (HCA), and intensity analyses of individual spectral bands exhibited comprehensive alterations in the polysaccharide and lipid contents and compositions of P. aeruginosa cultivated with S. salivarius M18 cell-free supernatant. These results indicate that S. salivarius M18 has the potential for the prevention or alleviation of different pathogen-induced infections along with the infections of oral pathogens.

Lactobacilli spp.: real-time evaluation of biofilm growth

BACKGROUND

Biofilm is a fundamental bacterial survival mode which proceeds through three main generalized phases: adhesion, maturation, and dispersion. Lactobacilli spp. (LB) are critical components of gut and reproductive health and are widely used probiotics. Evaluation of time-dependent mechanisms of biofilm formation is important for understanding of host-microbial interaction and development of therapeutic interventions. Time-dependent LB biofilm growth was studied in two systems: large biofilm output in continuous flow system (microfermenter (M), Institute Pasteur, France) and electrical impedance-based real time label-free cell analyzer (C) (xCELLigence, ACEA Bioscience Inc., San Diego, CA). L. plantarum biofilm growth in M system was video-recorded, followed by analyses using IMARIS software (Bitplane, Oxford Instrument Company, Concord, MA, USA). Additionally, whole genome expression and analyses of attached (A) and dispersed (D) biofilm phases at 24 and 48 h were performed.

RESULTS

The dynamic of biofilm growth of L. plantarum was similar in both systems except for D phases. Comparison of the transcriptome of A and D phases revealed, that 121 transcripts differ between two phases at 24 h. and 35 transcripts - at 48 h. of M growth. The main pathways, down-regulated in A compared to D phases after 24 h. were transcriptional regulation, purine nucleotide biosynthesis, and L-aspartate biosynthesis, and the upregulated pathways were fatty acid and phospholipid metabolism as well as ABC transporters and purine nucleotide biosynthesis. Four LB species differed in the duration and amplitude of attachment phases, while growth phases were similar.

CONCLUSION

LB spp. biofilm growth and propagation area dynamic, time-dependent processes with species-specific and time specific characteristics. The dynamic of LB biofilm growth agrees with published pathophysiological data and points out that real time evaluation is an important tool in understanding growth of microbial communities.

New Nanotechnologies for the Treatment and Repair of Skin Burns Infections

Burn wounds are highly debilitating injuries, with significant morbidity and mortality rates worldwide. In association with the damage of the skin integrity, the risk of infection is increased, posing an obstacle to healing and potentially leading to sepsis. Another limitation against healing is associated with antibiotic resistance mainly due to the use of systemic antibiotics for the treatment of localized infections. Nanotechnology has been successful in finding strategies to incorporate antibiotics in nanoparticles for the treatment of local wounds, thereby avoiding the systemic exposure to the drug. This review focuses on the most recent advances on the use of nanoparticles in wound dressing formulations and in tissue engineering for the treatment of burn wound infections.

Efficacy of Using Probiotics with Antagonistic Activity against Pathogens of Wound Infections: An Integrative Review of Literature

The skin and its microbiota serve as physical barriers to prevent invasion of pathogens. Skin damage can be a consequence of illness, surgery, and burns. The most effective wound management strategy is to prevent infections, promote healing, and prevent excess scarring. It is well established that probiotics can aid in skin healing by stimulating the production of immune cells, and they also exhibit antagonistic effects against pathogens via competitive exclusion of pathogens. Our aim was to conduct a review of recent literature on the efficacy of using probiotics against pathogens that cause wound infections. In this integrative review, we searched through the literature published in the international following databases: PubMed, ScienceDirect, Web of Science, and Scopus using the search terms “probiotic” AND “wound infection.” During a comprehensive review and critique of the selected research, fourteen in vitro studies, 8 animal studies, and 19 clinical studies were found. Two of these in vitro studies also included animal studies, yielding a total of 39 articles for inclusion in the review. The most commonly used probiotics for all studies were well-known strains of the species Lactobacillus plantarum, Lactobacillus casei, Lactobacillus acidophilus, and Lactobacillus rhamnosus. All in vitro studies showed successful inhibition of chosen skin or wound pathogens by the selected probiotics. Within the animal studies on mice, rats, and rabbits, probiotics showed strong opportunities for counteracting wound infections. Most clinical studies showed slight or statistically significant lower incidence of surgical site infections, foot ulcer infection, or burn infections for patients using probiotics. Several of these studies also indicated a statistically significant wound healing effect for the probiotic groups. This review indicates that exogenous and oral application of probiotics has shown reduction in wound infections, especially when used as an adjuvant to antibiotic therapy, and therefore the potential use of probiotics in this field remains worthy of further studies, perhaps focused more on typical skin inhabitants as next-generation probiotics with high potential.

The Impact of Microbial Communities on Wound Healing: A Review

Chronic, nonhealing wounds place an enormous burden on both the health care system and patients, with no definitive treatments available. There has been increasing evidence that the microbial composition of wounds may play an important role in wound healing. Culture-independent methods for bacterial detection and analysis have revealed the wound microbiome to be much more diverse and complex than culture alone. Such methods primarily rely on targeted amplification and sequencing of various hypervariable regions of the bacterial 16S rRNA for phylogenetic analysis. To date, there have been several studies utilizing culture-independent methods to investigate the microbiome of a variety of chronic wounds, including venous insufficiency ulcers, pressure ulcers, and diabetic foot ulcers. Major bacteria found include Staphylococcus, Streptococcus, Corynebacterium, Pseudomonas, and various anaerobes. Current studies suggest that improved healing and outcomes may be correlated with increased bacterial diversity and instability of the microbiome composition of a wound. However, the exact role of the microbiome in wound healing remains poorly understood. While the current research is promising, studies are very heterogeneous, hindering comparisons of findings across different research groups. In addition, more studies are needed to correlate microbiome findings with clinical factors, as well as in the relatively unexplored fields of acute wounds and nonbacterial microbiomes, such as the wound mycobiome and virome. Better understanding of the various aspects of the microorganisms present in wounds may eventually allow for the manipulation of the wound microbiota in such a way as to promote healing, such as through bacteriophage therapies or probiotics.

Fabrication of Electrospun Probiotic Functionalized Nanocomposite Scaffolds for Infection Control and Dermal Burn Healing in a Mice Model

The importance of microbiota paves the way to use microbial cells as medicines to treat pathobiomic diseases. This study reported the fabrication of probiotic (Enterococcus mundtii QAUEM2808)-functionalized nanocomposite scaffolds of poly(vinyl alcohol)/poly(vinylpyrrolidone)/glycerol via electrospinning. Scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis resolved the living composite structure and supported the encapsulation of E. mundtii throughout the nanostructured (318 ± 12 nm) fibers of bioscaffold membranes. The shelf life evaluation of 4-week-old samples supported that bioscaffolds showed an enhancement in probiotic survival count by 2.78 ± 0.10 log₁₀ colony-forming units (cfu) versus counterpart biodispersion. The swelling and antagonistic evaluation showed that a bioscaffold is degradable in a simulated wound fluid which is essential for activation of probiotic strains to antagonize infection-causing Gram-positive and Gram-negative pathogens. A second-degree contact burn was made on the dorsum of male BALB/c mice (n = 30). The wounds were left open for 2 days to mimic burn contamination, and the mice were randomized into negative (untreated), positive (silver sulfadiazine cream), vehicle (biodispersion and nanoscaffold), and experimental bioscaffold groups (n = 6/group). These treatments were applied on 2, 6, 10, and 14 days postburn. A comparative wound closure, histopathology, and wound microbial evaluation demonstrated that the bioscaffolds accelerate epithelialization, collagen deposition, and hair follicle formation, inhibit harmful bacteria, and provide interference benefits. In particular, the probiotic active bioscaffold membrane could serve as a novel candidate to control infections and speed up the healing of burn wounds.

Staphylococcus epidermidis role in the skin microenvironment

Wound healing is a complex dynamic physiological process in response to cutaneous destructive stimuli that aims to restore the cutaneous' barrier role. Deciphering the underlying mechanistic details that contribute to wound healing will create novel therapeutic strategies for skin repair. Recently, by using state-of-the-art technologies, it was revealed that the cutaneous microbiota interact with skin immune cells. Strikingly, commensal Staphylococcus epidermidis-induced CD8+ T cells induce re-epithelization of the skin after injury, accelerating wound closure. From a drug development perspective, the microbiota may provide new therapeutic candidate molecules to accelerate skin healing. Here, we summarize and evaluate recent advances in the understanding of the microbiota in the skin microenvironment.

The role of thermal injury on intestinal bacterial translocation and the mitigating role of probiotics: A review of animal and human studies

INTRODUCTION

Burn patients represent a combination of nutritionally deplete and calorically demanding individuals who are susceptible to morbidity and mortality. A source of sepsis in thermal injury patients is the gastrointestinal tract with its interaction of normal and potentially pathogenic bacteria. The normal flora of the intestines maintains the equilibrium of the gut and prevents bacterial translocation (BT) through numerous mechanisms, all of which are disrupted as a consequence of thermal injury. Probiotic supplements with varying strains of bacteria have the potential to stabilize the integrity of the gut lining and decrease the incidence of BT after thermal injury.

METHODS

A literature review was conducted for animal and human studies in English addressing probiotic therapy in thermal injury. Keywords, "probiotics," "thermal injury" and "burn" were utilized. Reference lists for each analyzed article were also examined to ensure completeness of literature search. Each article was reviewed for methodology, results and conclusions.

RESULTS

Eleven and six unique articles were identified addressing probiotics in thermal injury in animal and human studies, respectively. Heterogeneity between studies and limited demographic and outcome reporting prevented meta-analysis and comprehensive recommendations to be formalized.

CONCLUSION

While heterogeneity did not allow for meta-analysis, the results overall suggest a preventative, if not therapeutic, potential for probiotics in patients after thermal injury. Despite initial concern that probiotic therapy could lead to systemic infection in immune compromised individuals, this was not observed in the analyzed studies. Numerous unanswered questions exist in regards to optimizing probiotic therapy in patients after thermal injury.

Impact of probiotics on pathogen survival in an innovative human plasma biofilm model (hpBIOM)

BACKGROUND

Despite of medical advances, the number of patients suffering on non-healing chronic wounds is still increasing. This fact is attended by physical and emotional distress and an economic load. The majority of chronic wounds are infected of harmful microbials in a protecting extracellular matrix. These biofilms inhibit wound healing. Biofilm-growing bacteria developed unique survival properties, which still challenge the appropriate wound therapy. The present in-vitro biofilm models are not suitable for translational research. By means of a novel in-vivo like human plasma biofilm model (hpBIOM), this study systematically analysed the influence of 3 probiotics on the survival of five clinically relevant pathogenic microorganisms.

METHODS

Human plasma was used to produce the innovate biofilm. Pathogenic microorganisms were administered to the plasma. By stimulating the production of a fibrin scaffold, stable coagula-like discs with integrated pathogens were produced. The five clinically relevant pathogens P. aeruginosa, S. aureus, S. epidermidis, E. faecium and C. albicans were challenged to the probiotics L. plantarum, B. lactis and S. cerevisiae. The probiotics were administered on top of the biofilm and the survival was quantified after 4 h and 24 h of incubation. For statistics, two-way ANOVA with post-hoc Tukey's HSD test was applied. P-value > 0.05 was considered to be significant.

RESULTS

SEM micrographs depicted the pathogens on the surface of the fibrin scaffold, arranged in close proximity and produced the glycocalyx. The application of probiotics induced different growth-reducing capacities towards the pathogens. B. lactis and S. cerevisiae showed slight bacteria-reducing properties. The survival of C. albicans was not affected at all. The most antimicrobial activity was detected after the treatment with L. plantarum.

CONCLUSIONS

This study successfully reproduced a novel human biofilm model, which provides a human wound milieu and individual immune competence. The success of bacteriotherapy is dependent on the strain combination, the number of probiotics and the activity of the immune cells. The eradicating effect of L. plantarum on P. aeruginosa should be emphasized.

Recent Advances in Non-Conventional Antimicrobial Approaches for Chronic Wound Biofilms: Have We Found the 'Chink in the Armor'?

Chronic wounds are a major healthcare burden, with huge public health and economic impact. Microbial infections are the single most important cause of chronic, non-healing wounds. Chronic wound infections typically form biofilms, which are notoriously recalcitrant to conventional antibiotics. This prompts the need for alternative or adjunct ‘anti-biofilm’ approaches, notably those that account for the unique chronic wound biofilm microenvironment. In this review, we discuss the recent advances in non-conventional antimicrobial approaches for chronic wound biofilms, looking beyond standard antibiotic therapies. These non-conventional strategies are discussed under three groups. The first group focuses on treatment approaches that directly kill or inhibit microbes in chronic wound biofilms, using mechanisms or delivery strategies distinct from antibiotics. The second group discusses antimicrobial approaches that modify the biological, chemical or biophysical parameters in the chronic wound microenvironment, which in turn enables the disruption and removal of biofilms. Finally, therapeutic approaches that affect both, biofilm bacteria and microenvironment factors, are discussed. Understanding the advantages and limitations of these recent approaches, their stage of development and role in biofilm management, could lead to new treatment paradigms for chronic wound infections. Towards this end, we discuss the possibility that non-conventional antimicrobial therapeutics and targets could expose the ‘chink in the armor’ of chronic wound biofilms, thereby providing much-needed alternative or adjunct strategies for wound infection management.

The Cutaneous Microbiome and Wounds: New Molecular Targets to Promote Wound Healing

The ecological community of microorganisms in/on humans, termed the microbiome, is vital for sustaining homeostasis. While culture-independent techniques have revealed the role of the gut microbiome in human health and disease, the role of the cutaneous microbiome in wound healing is less defined. Skin commensals are essential in the maintenance of the epithelial barrier function, regulation of the host immune system, and protection from invading pathogenic microorganisms. In this review, we summarize the literature derived from pre-clinical and clinical studies on how changes in the microbiome of various acute and chronic skin wounds impact wound healing tissue regeneration. Furthermore, we review the mechanistic insights garnered from model wound healing systems. Finally, in the face of growing concern about antibiotic-resistance, we will discuss alternative strategies for the treatment of infected wounds to improve wound healing and outcomes. Taken together, it has become apparent that commensals, symbionts, and pathogens on human skin have an intimate role in the inflammatory response that highlights several potential strategies to treat infected, non-healing wounds. Despite these promising results, there are some contradictory and controversial findings from existing studies and more research is needed to define the role of the human skin microbiome in acute and chronic wound healing.

Pericytes reduce inflammation and collagen deposition in acute wounds

BACKGROUND

Pericytes have been shown to have mesenchymal stromal cell-like properties and play a role in tissue regeneration. The goal of this study was to determine whether the addition of a pericyte sheet to a full-thickness dermal wound would enhance the healing of an acute wound.

METHODS

Human muscle-derived pericytes and human dermal fibroblasts were formed into cell sheets, then applied to full-thickness excisional wounds on the dorsum of nu/nu mice. Histology was performed to evaluate epidermal and dermal reformation, inflammation and fibrosis. In addition, real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was used to determine cytokine response.

RESULTS

Pericytes were detected in the wounds until day 16 but not fibroblasts. Decrease in wound size was noted in pericyte sheet-treated wounds. Enhanced neo-vascularization and healthy granulation tissue formation were noted in the pericyte-treated wounds. Expression of type I collagen messenger RNA (mRNA) was significantly higher in the fibroblast-treated group, whereas Type III collagen mRNA showed significant increase in the pericyte group at days 3, 6 and 9 compared with the fibroblast and no-cell groups. Trichrome staining revealed thick unorganized collagen fibrils in the fibroblast-treated wounds, whereas pericyte-treated wounds contained thinner and more alligned collagen fibrils. Tumor necrosis factor (TNF)-α mRNA levels were increased in the fibroblast-treated wounds compared with pericyte-treated wounds.

DISCUSSION

The addition of pericytes may confer beneficial effects to wound healing resulting in reduced recruitment of inflammatory cells and collagen I deposition, potential to enhance wound closure and better collagen alignment promoting stronger tissue.

Skin Protective Nutraceuticals: The Current Evidence in Brief

Nutraceuticals are important for healthy skin maintenance. Probiotics, phenolics, and vitamins are just a few of the nutraceuticals meant to potentially prevent and assist medical management of dermatologic conditions. Among these, probiotics, vitamin E, and green tea catechins may offer the broadest array of skin protective mechanisms with probiotics having the greatest clinical range. Probiotics’ amelioration of atopic dermatitis and opportunistic infections of skin burns has been targeted in recent research efforts. This includes the improvement of Scoring Atopic Dermatitis index scores, p = 0.02, with intact Lactobacillus rhamnosus Goldin and Gorbach (LGG) in comparison to heat inactivated LGG or placebo. Lactobacillus reuteri used prior to or concurrently with Staphylococcus aureus infection can increase epidermal keratinocyte survival, p < 0.01. Phenolics may not have been extensively studied for atopic dermatitis or skin burns. However, phenolics do have a role in photoprotection. The phenolic rutin increases ultraviolet B radiation filter reactive oxygen species scavenging at 75%, p < 0.002, and peak wavelength absorption, p < 0.001. While oral and topical probiotics have untapped potential for atopic dermatitis amelioration and skin infection prevention, phenolics will be increasingly used for photoprotection. With optimized bioavailability, dosage, and formulation, nutraceuticals will become crucial for healthy skin maintenance.

Probiotic use in an infectious disease setting

INTRODUCTION

The lethality of infectious diseases and deep concern over growing antimicrobial resistance make it essential that alternative or adjunct therapies be developed. Areas covered: Using papers published in PubMed, a case is presented to consider beneficial microbes as a means to improve management of infectious diseases. Clinical evidence is mounting that certain probiotic microbes can contribute to this armamentarium. These could have an immediate effect against necrotizing enterocolitis, pre- and post-surgical procedures, antibiotic-associated infections, urogenital infections in women and for reducing the severity and duration of respiratory infections. While further studies will always be warranted irrespective of the intervention, and quality assurance and patient safety must remain a priority, the main barrier to implementation may well be unwarranted hesitation amongst physicians, healthcare administrators and regulators. Meanwhile, patients are already taking things into their own hands at a time when their knowledge of product selection is poor and clinical guidance is invariably missing. Expert commentary: Until vaccines and other alternatives emerge, it would be foolhardy to not use best practices to bring probiotics into mainstream infectious disease management. Our ability to manipulate microbial-host interactions offers hope before the last antibiotic stops being effective.