Activated carbon-chitosan hydrogel dressing loaded with LL37 microspheres for the treatment of infected wounds: In vivo antimicrobial and antitoxin assessment

Wound healing is a complex process which is crucial for recovery. Delayed wound healing which is caused by the presence of pathogens has posed significant clinical implications affecting millions of patients globally. Wounds infection caused by Pseudomonas aeruginosa present significant challenges due to their resistance to multiple antimicrobial drugs. The Gram-negative bacteria secretes endotoxin lipopolysaccharide (LPS), which impede wound healing and may lead to severe complications, including life-threatening sepsis. Previously, our laboratory has successfully developed a new hydrogel containing a synthetic antimicrobial peptide as an alternative therapy to conventional antibiotics. This hydrogel contains LL37 microspheres embedded into activated carbon-chitosan hydrogel (LL37-AC-CS). LL37-AC-CS has shown desirable physicochemical properties as well as promising antimicrobial and antitoxin activities in vitro. This current study has two main objectives. The first is to evaluate the in vivo antimicrobial efficacy of LL37-AC-CS hydrogel in full-thickness rat wounds infected with P. aeruginosa. The second objective is to investigate the antitoxin efficacy on the rat wound models treated with E. coli endotoxins LPS. The wound healing efficacy was assessed in terms of the macroscopic appearance, wound contraction rate, histology, and wound tissue biochemical markers. As a result, the LL37-AC-CS hydrogel exhibited remarkable antimicrobial and antitoxin efficacy as compared to the controls. The wound healing efficacy was evident in increased wound closure rate and decrease in bacterial bioburden, and favourable changes in wound healing biomarkers namely the myeloperoxidase, interleukin-6 and tumour necrosis factor α. The elevation of hydroxyproline levels in the LPS-treated wound model indicates there was collagen synthesis. In conclusion, the results presented in this study have significantly enhanced our comprehension of the LL37-AC-CS hydrogel's potential in wound healing. Specifically, the research highlights its effectiveness in eliminating endotoxins and preventing bacterial growth.

Myeloperoxidase as a biomarker in periodontal disease: electrochemical detection using printed screen graphene electrodes

Periodontal disease is a common oral health issue marked by inflammation and the breakdown of tissues. Early detection of biomarkers associated with periodontal disease (PD) can significantly aid in timely diagnosis and intervention. Myeloperoxidase (MPO) is an enzyme abundantly present in neutrophils and has been associated in the pathogenesis of PD. Here, we present a novel approach for the electrochemical detection of MPO using printed screen graphene electrodes coupled with principal component analysis (PCA) for data analysis. We employed cyclic voltammetry to characterize the electrochemical behavior of MPO using potassium ferrocyanide and hydrogen peroxide. The process was controlled by species diffusion on the electrode surface using a scan rate spanning from 10 to 400 mVs-1. In addition, we investigated the detection of hydrogen peroxide, a substrate of MPO, as a method to indirectly asses MPO electroactivity, leveraging a redox potential of - 500 mV. Saliva samples were collected and analyzed using the developed electrochemical sensor, followed by principal component analysis to differentiate between healthy and diseased samples based on MPO levels. Our findings demonstrate the feasibility of using printed screen graphene electrodes for the sensitive and selective detection of MPO, offering a promising approach for early diagnosis and monitoring of periodontal disease. In conclusion, our results highlight the potential of MPO as a robust biomarker for periodontal disease and highlight the utility of electrochemical sensing coupled with PCA analysis for sensitive and specific detection in clinical settings.

Image-based non-invasive assessment of suction blister wounds for clinical safety and efficacy

Recognising the need for objective imaging-based technologies to assess wound healing in clinical studies, the suction blister wound model offers an easily accessible wound model that creates reproducible epidermal wounds that heal without scarring. This study provides a comprehensive methodology for implementing and evaluating photography-based imaging techniques utilising the suction blister wound model. Our method encompasses a protocol for capturing consistent, high-quality photographs and procedures for quantifying these images via a visual wound healing score and a computer-assisted colour analysis of wound exudation and wound redness. We employed this methodology on 16 suction blister wounds used as controls in a clinical phase-1 trial. Our method enabled us to discern and quantify subtle differences between individual wounds concerning healing progress, erythema and wound exudation. The wound healing score exhibited a high inter-rater agreement. There was a robust correlation between the spectrophotometer-measured erythema index and photography-based wound redness, as well as between dressing protein content and photography-based dressing yellowness. In conclusion, this study equips researchers conducting clinical wound studies with reproducible methods that may support future wound research and aid in the development of new treatments.

Comparative analysis of electrochemical and optical sensors for detection of chronic wounds biomarkers: A review

Chronic wounds (CW) present a significant healthcare challenge due to their prolonged healing time and associated complications. To effectively treat these wounds and prevent further deterioration, monitoring their healing progress is crucial. Traditional wound assessment methods relying on visual inspection and subjective evaluation are prone to inter-observer variability. Biomarkers play a critical role in objectively evaluating wound status and predicting healing outcomes, providing quantitative measures of wound healing progress, inflammation, infection, and tissue regeneration. Recent attention has been devoted to identifying and validating CW biomarkers. Various studies have investigated potential biomarkers, including growth factors, cytokines, proteases, and extracellular matrix components, shedding light on the complex molecular and cellular processes within CW. This knowledge enables a more targeted and personalized approach to wound management. Accurate and sensitive techniques are necessary for detecting CW biomarkers. Thus, this review compares and discusses the use of electrochemical and optical sensors for biomarker determination. The advantages and disadvantages of these sensors are highlighted. Differences in detection capabilities and characteristics such as non-invasiveness, portability, high sensitivity, specificity, simplicity, cost-effectiveness, compatibility with point-of-care applications, and real-time monitoring of wound biomarkers will be pointed out and compared. In summary, this work provides an overview of CW, explores the emerging field of CW biomarkers, and discusses methods for detecting these biomarkers, with a specific focus on optical and electrochemical sensors. The potential of further research and development in this field for advancing wound care and improving patient outcomes will also be noted.

Novel fluorometric protocol for assessing myeloperoxidase activity

Neutrophil myeloperoxidase (MPO) is an essential enzyme for the innate immune system. Measuring MPO activity is vital for understanding neutrophil characteristics and functions in various diseases. MPO activity can be measured using several methods, including spectrophotometric and fluorometric protocols. This paper introduces a fluorometric method for specifically quantifying MPO activity based on the H2O2-dependent oxidation of thiamine. We optimized this new method using the robust statistical approach response surface methodology (RSM) and Box Benken Design (BBD). We extensively examined the effects of several experimental parameters using the RSM methodology and determined the best conditions for accurate and sensitive MPO activity measurement. The optimal conditions were determined using the analysis of variance (ANOVA) for second-order polynomial equations. The resulting F-value (4.86) indicated that the model was significant. However, the lack-of-fitness F-value (1.79) suggested it did not differ significantly from the corresponding p-value. The greatest MPO activity (30 ± 2 U L-1) was obtained under optimum conditions, which were 1000 µM of H2O2, 10 min incubation time, and 1000 µM of thiamine. Our results suggest that this advanced fluorometric method has significant accuracy, sensitivity, and linearity up to 60 IU. The new and standard colorimetric methods also showed a good correlation. These results indicate that the new fluorometric method can be dependable and efficient for assessing MPO activity. The new method is characterized by excellent accuracy, sensitivity, and linearity, making it a valuable protocol for researchers and clinicians interested in assessing MPO activity.

Synthetic neutrophil extracellular traps dissect bactericidal contribution of NETs under regulation of α-1-antitrypsin

Deciphering the complex interplay of neutrophil extracellular traps (NETs) with the surrounding environment is a challenge with notable clinical implications. To bridge the gap in knowledge, we report our findings on the antibacterial activity against Pseudomonas aeruginosa of synthetic NET-mimetic materials composed of nanofibrillated DNA-protein complexes. Our synthetic system makes component-by-component bottom-up analysis of NET protein effects possible. When the antimicrobial enzyme neutrophil elastase (NE) is incorporated into the bactericidal DNA-histone complexes, the resulting synthetic NET-like structure exhibits an unexpected reduction in antimicrobial activity. This critical immune function is rescued upon treatment with alpha-1-antitrypsin (AAT), a physiological tissue-protective protease inhibitor. This suggests a direct causal link between AAT inhibition of NE and preservation of histone-mediated antimicrobial activity. These results help better understand the complex and, at times, contradictory observations of in vivo antimicrobial effects of NETs and AAT by excluding neutrophil, cytokine, and chemoattractant contributions.

Pharmacological evaluation of antinociceptive and anti-inflammatory activities of LQFM202: a new piperazine derivative

Advances have been made in the search for new multi-target modulators to control pain and inflammation. Therefore, compound 3,5-di-tert-butyl-4-hydroxyphenyl)(4-methylpiperazin-1-yl)methanone (LQFM202) was synthesised and evaluated. First, in vitro assays were performed for COX-1, COX-2, and 5-LOX enzymes. Subsequently, adult female Swiss albino mice treated orally with LQFM202 at doses of 25-200 mg/kg were subjected to acetic acid-induced writhing, formalin-induced pain, carrageenan-induced hyperalgesia, carrageenan- or zymosan-induced paw oedema, or pleurisy. LQFM202 inhibited COX-1, COX-2, and LOX-5 (IC₅₀ = 3499 µM, 1565 µM, and 1343 µM, respectively). In acute animal models, LQFM202 (50, 100, or 200 mg/kg) decreased the amount of abdominal writhing (29%, 52% and 48%, respectively). Pain in the second phase of the formalin test was reduced by 46% with intermediate dose. LQFM202 (100 mg/kg) reduced the difference in nociceptive threshold in all 4 h evaluated (46%, 37%, 30%, and 26%, respectively). LQFM202 (50 mg/kg) decreased the carrageenan-oedema from the second hour (27%, 31% and 25%, respectively); however, LQFM202 (100 mg/kg) decreased the carrageenan-oedema in all hours evaluated (35%, 42%, 48% and 50%, respectively). When using zymosan, LQFM202 (50 mg/kg) decreased the oedema in all hours evaluated (33%, 32%, 31% and 20%, respectively). In the carrageenan-pleurisy test, LQFM202 (50 mg/kg) reduced significantly the number of polymorphonuclear cells (34%), the myeloperoxidase activity (53%), TNF-α levels (47%), and IL-1β levels (58.8%). When using zymosan, LQFM202 (50 mg/kg) reduced the number of polymorphonuclear and mononuclear cells (54% and 79%, respectively); and the myeloperoxidase activity (46%). These results suggest antinociceptive and anti-inflammatory effects of LQFM202.

A Host-Directed Approach to the Detection of Infection in Hard-to-Heal Wounds

Wound infection is traditionally defined primarily by visual clinical signs, and secondarily by microbiological analysis of wound samples. However, these approaches have serious limitations in determining wound infection status, particularly in early phases or complex, chronic, hard-to-heal wounds. Early or predictive patient-derived biomarkers of wound infection would enable more timely and appropriate intervention. The observation that immune activation is one of the earliest responses to pathogen activity suggests that immune markers may indicate wound infection earlier and more reliably than by investigating potential pathogens themselves. One of the earliest immune responses is that of the innate immune cells (neutrophils) that are recruited to sites of infection by signals associated with cell damage. During acute infection, the neutrophils produce oxygen radicals and enzymes that either directly or indirectly destroy invading pathogens. These granular enzymes vary with cell type but include elastase, myeloperoxidase, lysozyme, and cathepsin G. Various clinical studies have demonstrated that collectively, these enzymes, are sensitive and reliable markers of both early-onset phases and established infections. The detection of innate immune cell enzymes in hard-to-heal wounds at point of care offers a new, simple, and effective approach to determining wound infection status and may offer significant advantages over uncertainties associated with clinical judgement, and the questionable value of wound microbiology. Additionally, by facilitating the detection of early wound infection, prompt, local wound hygiene interventions will likely enhance infection resolution and wound healing, reduce the requirement for systemic antibiotic therapy, and support antimicrobial stewardship initiatives in wound care.

Rapid Colorimetric Detection of Wound Infection with a Fluidic Paper Device

Current procedures for the assessment of chronic wound infection are time-consuming and require complex instruments and trained personnel. The incidence of chronic wounds worldwide, and the associated economic burden, urge for simple and cheap point-of-care testing (PoCT) devices for fast on-site diagnosis to enable appropriate early treatment. The enzyme myeloperoxidase (MPO), whose activity in infected wounds is about ten times higher than in non-infected wounds, appears to be a suitable biomarker for wound infection diagnosis. Herein, we develop a single-component foldable paper-based device for the detection of MPO in wound fluids. The analyte detection is achieved in two steps: (i) selective immunocapture of MPO, and (ii) reaction of a specific dye with the captured MPO, yielding a purple color with increasing intensity as a function of the MPO activity in infected wounds in the range of 20–85 U/mL. Ex vivo experiments with wound fluids validated the analytic efficiency of the paper-based device, and the results strongly correlate with a spectrophotometric assay.

Advanced Wound Diagnostics: Toward Transforming Wound Care into Precision Medicine

Significance: Nonhealing wounds are an ever-growing global pandemic, with mortality rates and management costs exceeding many common cancers. Although our understanding of the molecular and cellular factors driving wound healing continues to grow, standards for diagnosing and evaluating wounds remain largely subjective and experiential, whereas therapeutic strategies fail to consistently achieve closure and clinicians are challenged to deliver individualized care protocols. There is a need to apply precision medicine practices to wound care by developing evidence-based approaches, which are predictive, prescriptive, and personalized. Recent Advances: Recent developments in "advanced" wound diagnostics, namely biomarkers (proteases, acute phase reactants, volatile emissions, and more) and imaging systems (ultrasound, autofluorescence, spectral imaging, and optical coherence tomography), have begun to revolutionize our understanding of the molecular wound landscape and usher in a modern age of therapeutic strategies. Herein, biomarkers and imaging systems with the greatest evidence to support their potential clinical utility are reviewed. Critical Issues: Although many potential biomarkers have been identified and several imaging systems have been or are being developed, more high-quality randomized controlled trials are necessary to elucidate the currently questionable role that these tools are playing in altering healing dynamics or predicting wound closure within the clinical setting. Future Directions: The literature supports the need for the development of effective point-of-care wound assessment tools, such as a platform diagnostic array that is capable of measuring multiple biomarkers at once. These, along with advances in telemedicine, synthetic biology, and "smart" wearables, will pave the way for the transformation of wound care into a precision medicine. Clinical Trial Registration number: NCT03148977.

Wound fluid sampling methods for proteomic studies: A scoping review

Understanding why some wounds are hard to heal is important for improving care and developing more effective treatments. The method of sample collection used is an integral step in the research process and thus may affect the results obtained. The primary objective of this study was to summarise and map the methods currently used to sample wound fluid for protein profiling and analysis. Eligible studies were those that used a sampling method to collect wound fluid from any human wound for analysis of proteins. A search for eligible studies was performed using MEDLINE, Embase and CINAHL Plus in May 2020. All references were screened for eligibility by one reviewer, followed by discussion and consensus with a second reviewer. Quantitative data were mapped and visualised using appropriate software and summarised via a narrative summary. After screening, 280 studies were included in this review. The most commonly used group of wound fluid collection methods were vacuum, drainage or use of other external devices, with surgical wounds being the most common sample source. Other frequently used collection methods were extraction from absorbent materials, collection beneath an occlusive dressing and direct collection of wound fluid. This scoping review highlights the variety of methods used for wound fluid collection. Many studies had small sample sizes and short sample collection periods; these weaknesses have hampered the discovery and validation of novel biomarkers. Future research should aim to assess the reproducibility and feasibility of sampling and analytical methods for use in larger longitudinal studies.

Automatic Identification of Myeloperoxidase Natural Inhibitors in Plant Extracts

The aim of this study is the development of an automated method for myeloperoxidase activity evaluation and its application in testing the inhibitory action of different plant extracts on the activity of the enzyme. This enzyme has its concentration increased in inflammatory and infectious processes, so it is a possible target to limit these processes. Therefore, an automatic sequential in-jection analysis (SIA) system was optimized and demonstrated that it is possible to obtain results with satisfactory accuracy and precision. With the developed method, plant extracts were studied, as promising candidates for MPO inhibition. In the group of selected plant extracts, IC50 values from 0.029 ± 0.002 mg/mL to 35.4 ± 3.5 mg/mL were obtained. Arbutus unedo L. proved to be the most inhibitory extract for MPO based on its phenolic compound content. The coupling of an automatic SIA method to MPO inhibition assays is a good alternative to other conventional methods, due to its simplicity and speed. This work also supports the pharmacological use of these species that inhibit MPO, and exhibit activity that may be related to the treatment of infection and inflammation.

Electrochemical quantification of biomarker myeloperoxidase

Point of care testing (PoCT) devices permit precise and rapid detection of disease-related biomarkers contributing to an early disease diagnosis and administration of an appropriate treatment. The enzyme myeloperoxidase (MPO) is a relevant biomarker for infection and inflammation events assessment; however its direct electrochemical quantification is hindered by the limited accessibility to the iron atom in its active center. Herein, such hindrance of the MPO biomolecule is overcome using the redox mediator 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). The charge involved in the electrochemical reduction of the MPO-oxidized ABTS is correlated with the concentration of MPO. The use of ABTS allowed for the electrochemical assessment of a wide range of MPO concentrations (10-1000 nM) including those reported for wound infections, chronic obstructive pulmonary disease and early adverse cardiac events. The developed electroanalytical approach is rapid and inexpensive, and thus suitable for implementation in PoCT devices.

Wound infection: A review of qualitative and quantitative assessment modalities

Surgical site infections (SSI) and chronic wounds represent a burden to patients and the health care system. One in 24 surgical patients will develop an SSI, making SSI the most common nosocomial infection in the USA. Early detection and monitoring of wound infection are critical for timely healing and return to normal function. However, the mainstay of wound infection diagnostic entails subjective clinical examination and semi-quantitative, invasive microbiological tests. In this review, we present current wound infection assessment modalities in the clinical and translational fields. There is a need for a point-of-care assessment tool that provides fast, accurate, and quantitative information on wound status, with minimal to no contact with the patient. In the next ten years, the evolution of wound diagnostic tools reported here may allow medical providers to optimize patient care while minimizing patient discomfort.

Diethylenetriamine/NONOate-doped alginate hydrogel with sustained nitric oxide release and minimal toxicity to accelerate healing of MRSA-infected wounds

This study demonstrates the development of a nitric oxide (NO)-releasing hydrogel wound dressing and its efficacy at accelerating methicillin-resistant Staphylococcus aureus (MRSA)-infected wound healing. A DETA/NONOate-doped alginate (Alg-DETA/NO) hydrogel was synthesized using alginate as a hydrogel-forming wound dressing material and diethylenetriamine/diazeniumdiolate (DETA/NONOate) as an NO donor. Alg-DETA/NO exhibited a prolonged NO release profile over a period of 4 days. The rheological properties of Alg-DETA/NO did not differ significantly from those of pure alginate. Importantly, Alg-DETA/NO showed potent antibacterial activity against MRSA, with minimal toxicity to mouse fibroblasts. The application of Alg-DETA/NO to MRSA-infected wounds in a mouse model showed a favorable wound healing with accelerated wound-size reduction and reduced skin bacterial infection. Additionally, histological examination revealed that Alg-DETA/NO reduced inflammation at the wound site and promoted re-epithelialization, angiogenesis, and collagen deposition. Thus, Alg-DETA/NO presented herein could serve as a safe and potent hydrogel dressing for the treatment of MRSA-infected wounds.

A non-contact device for fast screening of wound infections

Screening for wound infection relies on the expertise of the provider. Clinical diagnosis of infections based on wound swab/biopsy results often takes a few days and may not assess the full wound. There is a need for a non-invasive tool that can quickly and accurately diagnose wound infection. Leukocyte esterase strips are used to identify various infectious diseases. However, it is not clear whether infected wounds also have elevated leukocyte esterase activities as compared with non-infected wounds. To achieve the objective, a device was developed to detect elevated leukocyte esterase activities in wounds by measuring wound exudates adsorbed onto wound dressings in 3 minutes. The efficacy of the device in assessing leukocyte esterase activities across various chronic wounds was tested. Such measurements were unaffected by the type of underlying wound dressing. By correlating the device outputs with clinical adjudication of infection, we found that this device had high positive predictive values for diagnosing wound infection in a wide variety of chronic wounds. In addition, a positive device output increases the probability of detecting infected wounds, while the negative device output reduces the probability of detecting infected wounds. This rapid non-contact and disposable diagnostic tool may serve as a rapid and accurate indication of infection in the chronic wound.

Detection of synovial sepsis in horses using enzymes as biomarker

Background

Synovial sepsis is a commonly occurring, potentially career‐ending or even life‐threatening orthopaedic emergency. Diagnosis of synovial sepsis is currently primarily based on synovial fluid analysis, which often leaves diagnostic ambiguity due to overlap of clinicopathological parameters between septic and aseptic inflammatory synovitis.

Objectives

To evaluate the reliability of lysozyme (LYS), myeloperoxidase (MPO) and elastase (ELT) as biomarkers for synovial sepsis in horses using a photometric assay to measure increased enzyme activity.

Study design

Prospective, single‐blinded, analytical, clinical study.

Methods

Equine synovial samples were assigned to one of three groups: (1) healthy controls (n = 10), (2) aseptic (n = 27) and (3) septic synovitis (n = 30). The enzyme activity assays (LYS, MPO and ELT) were compared with standard synovial fluid parameters and broad‐range bacterial 16S rDNA PCR.

Results

LYS and MPO activities were significantly different between septic synovial samples, and both aseptic and control samples (P < .001, LYS: confidence interval [CI]: 2.25‐3.41, resp., 2.21‐3.8, MPO: CI 0.752‐1.6, resp., 0.639‐1.81). LYS achieved a 100% sensitivity and 100% specificity in differentiating between septic and aseptic (cut‐off value 751.4) or control (cut‐off: 484.6) samples (P < .001). MPO reached 93.33% sensitivity, 100% specificity for distinguishing septic from control (cut‐off value: 0.1254) synovial samples and 93.33% sensitivity, 81.48% specificity for discriminating between septic and aseptic (cut‐off value: 0.1305) synovial samples (P < .001). ELT activity could not be measured in any synovial sample. Both the LYS and the MPO measurements showed a highly significant correlation with PCR (LYS r = .79, MPO r = .69), synovial leukocyte count (LYS r = .752, MPO r = .571), % neutrophils (LYS r = .751, MPO r = 0.663) and each other (r = .744, all P < .001).

Main limitations

Variation in horses’ signalment, affected synovial structures and synovial fluid freezing times may have affected the discriminative power of this study.

Conclusions

Increased MPO and LYS activities allow reliable, rapid diagnosis of synovial sepsis with high sensitivity and specificity.

ELISA detection of MPO-DNA complexes in human plasma is error-prone and yields limited information on neutrophil extracellular traps formed in vivo

Over the past years, neutrophil extracellular traps (NETs) were shown to contribute to states of acute and chronic inflammatory disease. They are composed of expelled chromatin and decorated by neutrophil-derived proteins. Therefore, the analysis of DNA complexes with myeloperoxidase (MPO) by ELISA has become an attractive tool to measure NET formation in in vitro and in vivo samples. When we used a published MPO-DNA ELISA protocol and included an isotype control for the anti-MPO coating antibody, we observed high assay specificity for in vitro prepared NET samples, whereas the specificity for in vivo plasma samples was low. In addition, the assay failed to detect in vitro generated MPO-DNA complexes when spiked into plasma. Therefore, we set out to improve the specificity of the MPO-DNA ELISA for plasma samples. We found that the use of Fab fragments or immunoglobulins from different species or reversal of the antibody pair led to either a high background or a low dynamic range of detection that did not improve the specificity for plasma samples. Also, the use of higher plasma dilutions or pre-clearing of plasma immunoglobulins were ineffective. Finally, we found that a commercial reagent designed to block human anti-mouse antibodies and multivalent substances increased the detection window between the MPO antibody and isotype control for highly diluted plasma. We applied this modified ELISA protocol to analyze MPO-DNA complexes in human blood samples of acute and chronic inflammatory conditions. While markers of neutrophil activation and NET formation such as MPO, elastase and citrullinated histone H3 correlated significantly, we observed no correlation with the levels of MPO-DNA complexes. Therefore, we conclude that ELISA measurements of MPO-DNA complexes in human plasma are highly questionable regarding specificity of NET detection. In general, plasma analyses by ELISA should more frequently include isotype controls for antibodies to demonstrate target specificity.

Effects of Strong Acidic Electrolyzed Water in Wound Healing via Inflammatory and Oxidative Stress Response

Strong acidic electrolyzed water (StAEW) is known to inactivate microorganisms but is not fully explored in the medical field. This study is aimed at exploring StAEW as a potential wound care agent and its mechanism. StAEW (pH: 2.65, ORP: 1159 mV, ACC: 32.1 ppm) was sprayed three times a day to the cutaneous wounds of hairless mice for seven days. Wound morphological and histological features and immune-redox markers were compared with saline- (Sal-) and alcohol- (Alc-) treated groups. Results showed that the StAEW group showed a significantly higher wound healing percentage than the Sal group on days 2, 4, 5, and 6 and the Alc group on day 4. The StAEW group also showed earlier mediation on proinflammatory cytokines such as tumor necrosis factor-α, interleukin- (IL-) 6, IL-1β, and keratinocyte chemoattractant. In addition, basic fibroblast growth factor and platelet-derived growth factor were found to be significantly changed in favor of the fibroblast synthesis and angiogenesis. In line, the StAEW group showed a controlled amount of ROS and significantly decreased compared to the Alc group. The StAEW group also favored oxidative stress balance through antioxidant responses. Additionally, matrix metalloproteinases (MMP) 9 and MMP1 were also modulated for keratinocyte and cell migration. Taken together, this study has proven the wound healing effect of StAEW and its earlier mediation through oxidative and inflammatory responses.

The effects of adipose tissue-derived stem cells seeded onto the curcumin-loaded collagen scaffold in healing of experimentally- induced oral mucosal ulcers in rat

OBJECTIVES

Various therapeutic approaches, including stem-cell-based strategies and tissue engineering, have been proposed for oral ulcerative lesions. We investigated the effects of adipose tissue-derived stem cells (ADSCs) seeded onto the curcumin-loaded collagen scaffold in the mucosal healing of oral ulcers in rats.

MATERIALS AND METHODS

The current experimental study was conducted on 40 male Sprague-Dawley rats. Oral ulcers were created over both sides of buccal mucosa, and the rats were randomly divided into four equal groups: 1) an untreated group (negative control); 2) Teriadent-treated group (positive control); 3) group treated with curcumin-loaded collagen scaffold; and 4) group received the ADSCs (3 × 106 cells) seeded onto the curcumin-loaded collagen scaffold. Rats were sacrificed on 3rd and 7th day after ulceration for histopathological examination as well as measurement of tissue levels of myeloperoxidase (MPO), superoxide dismutase (SOD), and Interleukin-1 beta (IL-1β) activity.

RESULTS

Compared with the negative control, the tissue levels of MPO and IL-1β were significantly decreased in all treated groups (P<0.0001); however, the SOD activity was elevated (P<0.0001). The highest SOD activity as well as the lowest MPO and IL-1β levels were observed in the ADSCs-curcumin-loaded collagen scaffold group. The ulcer healing process at 3rd and 7th day follow-up was much more progressed in the ADSCs-curcumin-loaded collagen scaffold group in comparison with the untreated group (P=0.037 and P=0.004, respectively).

CONCLUSION

According to the findings of this study, ADSCs seeded onto the curcumin-loaded collagen scaffold seems to have a promising potential for oral ulcer healing applications.

The role of specific biomarkers, as predictors of post-operative complications following flexible ureterorenoscopy (FURS), for the treatment of kidney stones: a single-centre observational clinical pilot-study in 37 patients

BACKGROUND

The number of patients diagnosed and subsequently treated for kidney stones is increasing, and as such the number of post-operative complications is likely to increase. At present, little is known about the role of specific biomarkers, following flexible ureterorenoscopy (FURS) for the surgical treatment of kidney stones. The main aim of the study was to evaluate the role of kidney and infection biomarkers, in patients undergoing FURS.

METHODS

Included were 37 patients (24 males, 13 females), who underwent elective FURS, for the treatment of kidney stones. Venous blood samples were collected from each patient: pre-operatively, and at 30 min, 2 and 4 h post-operatively. Changes to kidney (NGAL, Cystatin-C) and infection (MPO, PCT) biomarkers was quantified by means of ELISA, Biomerieux mini-vidas and Konelab 20 analysers.

RESULTS

Four patients developed post-operative complications (3 - UTIs with urinary retention, 1 - urosepsis. NGAL concentration increased significantly following FURS (p = 0.034). Although no significant changes were seen in Cystatin C, MPO and PCT (p ≥ 0.05) some key clinical observation were noted. Limiting factors for this study were the small number of patients recruited and restriction in blood sampling beyond 4 h.

CONCLUSIONS

Although not confirmative, changes seen to biomarkers such as Cystatin C, NGAL and MPO in our observational clinical pilot-study may warrant further investigation, involving larger cohorts, to fully understand the role of these biomarkers and their potential association with post-operative complications which can develop following FURS.

A redox-responsive hyaluronic acid-based hydrogel for chronic wound management

Polymer-based hydrogels have been widely applied for chronic wound therapeutics, due to their well-acclaimed wound exudate management capability. At the same time, there is still an unmet clinical need for simple wound diagnostic tools to assist clinical decision-making at the point of care and deliver on the vision of patient-personalised wound management. To explore this challenge, we present a one-step synthetic strategy to realise a redox-responsive, hyaluronic acid (HA)-based hydrogel that is sensitive to wound environment-related variations in glutathione (GSH) concentration. By selecting aminoethyl disulfide (AED) as a GSH-sensitive crosslinker and considering GSH concentration variations in active and non-self-healing wounds, we investigated the impact of GSH-induced AED cleavage on hydrogel dimensions, aiming to build GSH-size relationships for potential point-of-care wound diagnosis. The hydrogel was also found to be non-cytotoxic and aided L929 fibroblast growth and proliferation over seven days in vitro. Such a material offers a very low-cost tool for the visual detection of a target analyte that varies dependent on the status of the cells and tissues (wound detection), and may be further exploited as an implant for fibroblast growth and tissue regeneration (wound repair).

Molecular Changes in Diabetic Wound Healing following Administration of Vitamin D and Ginger Supplements: Biochemical and Molecular Experimental Study

BACKGROUND

Circulating micro-RNAs are differentially expressed in various tissues and could be considered as potential regulatory biomarkers for T2DM and related complications, such as chronic wounds.

AIM

In the current study, we investigated whether ginger extract enriched with [6]-gingerol-fractions either alone or in combination with vitamin D accelerates diabetic wound healing and explores underlying molecular changes in the expression of miRNA and their predicted role in diabetic wound healing.

METHODS

Diabetic wounded mice were treated with [6]-gingerol-fractions (GF) (25 mg/kg of body weight) either alone or in combination with vitamin D (100 ng/kg per day) for two weeks. Circulating miRNA profile, fibrogenesis markers, hydroxyproline (HPX), fibronectin (FN), and collagen deposition, diabetic control variables, FBS, HbA1c, C-peptide, and insulin, and wound closure rate and histomorphometric analyses were, respectively, measured at days 3, 6, 9, and 15 by RT-PCR and immunoassay analysis.

RESULTS

Treatment of diabetic wounds with GF and vitamin D showed significant improvement in wound healing as measured by higher expression levels of HPX, FN, collagen, accelerated wound closure, complete epithelialization, and scar formation in short periods (11-13 days, (P < 0.01). On a molecular level, three circulating miRNAs, miR-155, miR-146a, and miR-15a, were identified in diabetic and nondiabetic skin wounds by PCR analysis. Lower expression in miR-155 levels and higher expression of miR-146a and miR-15a levels were observed in diabetic skin wounds following treatment with gingerols fractions and vitamin D for 15 days. The data showed that miRNAs, miR-146a, miR-155, and miR-15a, correlated positively with the expression levels of HPX, FN, and collagen and negatively with FBS, HbA1c, C-peptide, and insulin in diabetic wounds following treatment with GF and /or vitamin D, respectively.

CONCLUSION

Treatment with gingerols fractions (GF) and vitamin D for two weeks significantly improves delayed diabetic wound healing. The data showed that vitamin D and gingerol activate vascularization, fibrin deposition (HPX, FN, and collagen), and myofibroblasts in such manner to synthesize new tissues and help in the scar formation. Accordingly, three miRNAs, miR-155, miR-146a, and miR-15, as molecular targets, were identified and significantly evaluated in wound healing process. It showed significant association with fibrin deposition, vascularization, and reepithelialization process following treatment with GF and vitamin D. It proposed having anti-inflammatory action and promoting new tissue formation via vascularization process during the wound healing. Therefore, it is very interesting to consider miRNAs as molecular targets for evaluating the efficiency of nondrug therapy in the regulation of wound healing process.

Evaluation of the Biological Effects of Lyophilized Hydrophilic Extract of Rhus coriaria on Myeloperoxidase (MPO) Activity, Wound Healing, and Microbial Infections of Skin Wound Tissues

Impaired wound healing was mainly associated with severe microbial infections which significantly affect diagnostic and therapeutic strategies. Thus, in this study, the potential wound healing activity, anti-inflammatory, and antimicrobial activity of an aqueous extract of Rhus coriaria extract (AERc) were evaluated by wound contraction, scar formation, period of epithelization, MPO enzyme activity, collagenase-2 (MMP-8), hydroxyproline (HPX), and collagen deposition as markers of wound healing at different days of postwound. Phytoconstituents, microbial activity, and fibrogenic markers were screened by HPLC, disc-diffusion, and colorimetric assays. The animals were treated with Rhus coriaria extract (AERc) concentrations at doses of 5 mg.kg⁻¹and 10 mg.kg⁻¹, respectively. On days 6 and 9, the AERc-treated animals at doses of 5 mg.mL⁻¹ and 10 mg.mL⁻¹ exhibited a significant reduction in the wound area, increased deposition of collagen, HPX, and reduction in MMP-8, and MPO enzyme activity when compared with controls. Scar formation and epithelization were completed in 10 days compared to controls. In addition, in wounds infected separately with Staph. aureus or P. aeruginosa, the AERc extract significantly improved wound contraction, deposition of collagen, and HPx and reduced MMP-8 and MPO concentrations, with complete epithelization of wounds in 10-13 days compared to the saline-treated group. Hydrolyzable tannins, gallic acid, quercetin, and myricetin were the most common active components of AERc. In vitro, the AERc and its components were effective against a set of microbes especially Staph. aureus, P. aeruginosa, and Staph. aureus (MRSA). In conclusion, the results showed that antimicrobial, anti-inflammatory, and antioxidant activity of Rhus coriaria extract suggested its importance as a target for formulation of novel drugs against many microbial infections with minimal side effects and could play a good potential role in accelerating wound healing activity via promoting myofibroblast activity, increase of hydroxyproline and collagen deposition, and regulation of MMP-8 and MPO enzyme activities.

New myeloperoxidase detection system based on enzyme-catalysed oxidative synthesis of a dye for paper-based diagnostic devices

The severity and cost of wound infections strongly demands for simple and fast methods for wound infection determination. Point-of-care testing devices play a crucial role in order to achieve a fast diagnosis and early treatment. Myeloperoxidase (MPO) enzyme, detected in fluids of infected wounds has been postulated as a suitable biomarker for wound diagnostics. Here we present a new system for MPO detection, based on enzyme-catalysed oxidative synthesis of a dye that can be incorporated into paper-based point of care devices. Visual MPO detection has been achieved through the use of phenylenediamine, a common colourless hair dye precursor. MPO oxidation of these compounds yielded bright coloured products distinguishable from the colour of the wound environment. Immobilisation of the MPO substrates on paper strips was achieved through in situ interaction of the oxidised coloured product with branched polyethyleneimine. The colour reaction of the immobilized substrates, detectable by naked eye, responds to the MPO levels present in infected wound fluids revealing an easy system for incorporation of MPO detection in paper based diagnostic devices.

Wound Healing Effect of Slightly Acidic Electrolyzed Water on Cutaneous Wounds in Hairless Mice via Immune-Redox Modulation

Acidic electrolyzed water is an innovative sanitizer having a wide-spectrum of applications in food industry, and healthcare industry but little is known on its effect and mechanism in wound healing. The study was conducted to identify the effect and mechanism of slightly acidic electrolyzed water (SAEW) on cutaneous wounds in hairless mice. SAEW (pH: 5-6.5, oxidation reduction potential: 800 mV, chlorine concentration: 25 ppm) was prepared through electrolysis of water and was applied to the wounds of hairless mice three times a day for seven days. Wound size, immune response and oxidative stress were explored and compared to conventional agents such as Betadine and alcohol. We found that SAEW-treated group showed the highest wound reduction percentage (p<0.01). Antioxidant activities such as glutathione peroxidase, catalase and myeloperoxidase activities of SAEW group surpassed the total reactive oxygen species in skin. Nuclear factor erythroid-2-related-factor-2 and aryl hydrocarbon receptor were upregulated in SAEW group. Further, SAEW recruited the production of intracellular calcium and promoted its utilization for faster healing. In line, SAEW treatment decreased pro-inflammatory cytokines [interleukin (IL)-1β, IL-6, keratinocyte chemoattractant, and tumor necrosis factor-α] in serum. Other hallmarks of wound healing, matrixmetalloproteinases (MMP)1 and MMP9 were also upregulated. Collectively, our study indicates that SAEW is effective in wound healing of hairless mice via immune-redox modulation, and heals better/faster than conventional agents.

Anti-inflammatory and wound healing activities of calophyllolide isolated from Calophyllum inophyllum Linn

Due to the high-cost and limitations of current wound healing treatments, the search for alternative approaches or drugs, particularly from medicinal plants, is of key importance. In this study, we report anti-inflammatory and wound healing activities of the major calophyllolide (CP) compound isolated from Calophyllum inophyllum Linn. The results showed that CP had no effect on HaCaT cell viability over a range of concentrations. CP reduced fibrosis formation and effectively promoted wound closure in mouse model without causing body weight loss. The underlying molecular mechanisms of wound repair by CP was investigated. CP markedly reduced MPO activity, and increased M2 macrophage skewing, as shown by up-regulation of M2-related gene expression, which is beneficial to the wound healing process. CP treatment prevented a prolonged inflammatory process by down-regulation of the pro-inflammatory cytokines—IL-1β, IL-6, TNF-α, but up-regulation of the anti-inflammatory cytokine, IL-10. This study is the first to indicate a plausible role for CP in accelerating the process of wound healing through anti-inflammatory activity mechanisms, namely, by regulation of inflammatory cytokines, reduction in MPO, and switching of macrophages to an M2 phenotype. These findings may enable the utilization of CP as a potent therapeutic for cutaneous wound healing.

Peptide Inhibitor of Complement C1 Inhibits the Peroxidase Activity of Hemoglobin and Myoglobin

Hemoglobin is the natural carrier of oxygen in red blood cells (RBCs). While intracellular hemoglobin provides life-sustaining oxygen transport, extracellular free hemoglobin displays toxicity due to inherent peroxidase activity generating reactive oxygen species that subsequently react with the hemoglobin molecule to produce toxic heme degradation products resulting in free radicals, oxidative stress damage, and lipid peroxidation. We have recently demonstrated that Peptide Inhibitor of Complement C1 (PIC1) inhibits peroxidase activity of the heme-based enzyme myeloperoxidase. To elucidate whether PIC1 could inhibit peroxidase activity of hemoglobin, we evaluated the consequence of PIC1 on RBC lysates, methemoglobin, and myoglobin using tetramethylbenzidine (TMB) as an oxidation target. PIC1 reversibly and dose-dependently prevented TMB oxidation to tetramethylbenzidine diimine by RBC lysates, methemoglobin, and myoglobin, having comparable activity to the inhibitor 4-aminobenzoic acid hydrazide. PIC1 inhibited TMB oxidation of RBC lysates similar to L-cysteine suggesting that the two cysteine residues contained in PIC1 may mediate peroxidase activity. PIC1 also inhibited heme destruction by NaOCl for RBC lysates, hemoglobin, and myoglobin as assayed by preservation of the Soret absorbance peak in the presence of NaOCl and reduction in free iron release. In conclusion, PIC1 inhibits peroxidase activity of hemoglobin and myoglobin likely via an antioxidant mechanism.

Antimicrobial peptide-gold nanoscale therapeutic formulation with high skin regenerative potential

Chronic skin wounds affect ≈3% of persons aged >60years (Davies et al., 2007) [1]. These wounds are typically difficult to heal by conventional therapies and in many cases they get infected making even harder the regeneration process. The antimicrobial peptide (AMP) LL37 combines antimicrobial with pro-regenerative properties and thus represents a promising topical therapy to address both problems. Here, we investigated the wound healing potential of soluble and immobilized LL37 (LL37-conjugated gold nanoparticles, LL37-Au NPs), both in vitro (migration of keratinocytes) and in vivo (skin wound healing). Our results show that LL37-Au NPs, but not LL37 peptide, have the capacity to prolong the phosphorylation of EGFR and ERK1/2 and enhance the migratory properties of keratinocytes in a large in vitro wound model. We further report that both LL37 and LL37-Au NPs promote keratinocyte migration by the transactivation of EGFR, a process that seems to be initiated at the P2X7 receptor, as confirmed by chemical and genetic inhibition studies. Finally, we show in vivo that LL37-Au NPs have higher wound healing activity than LL37 peptide in a splinted mouse full thickness excisional model. Animal wounds treated by LL37-Au NPs have higher expression of collagen, IL6 and VEGF than the ones treated with LL37 peptide or NPs without LL37. Altogether, the conjugation of AMPs to NPs offers a promising platform to enhance their pro-regenerative properties.

Inhibition of Myeloperoxidase Activity in Cystic Fibrosis Sputum by Peptide Inhibitor of Complement C1 (PIC1)

Myeloperoxidase is the major peroxidase enzyme in neutrophil granules and implicated in contributing to inflammatory lung damage in cystic fibrosis. Free myeloperoxidase is present in cystic fibrosis lung fluid and generates hypochlorous acid. Here we report a new inhibitor of myeloperoxidase activity, Peptide Inhibitor of Complement C1 (PIC1). Using TMB as the oxidizing substrate, PIC1 inhibited myeloperoxidase activity in cystic fibrosis sputum soluble fractions by an average of a 3.4-fold decrease (P = 0.02). PIC1 also dose-dependently inhibited myeloperoxidase activity in a neutrophil lysate or purified myeloperoxidase by up to 28-fold (P < 0.001). PIC1 inhibited myeloperoxidase activity similarly, on a molar basis, as the specific myeloperoxidase inhibitor 4-Aminobenzoic acid hydrazide (ABAH) for various oxidizing substrates. PIC1 was able to protect the heme ring of myeloperoxidase from destruction by NaOCl, assayed by spectral analysis. PIC1 incubated with oxidized TMB reversed the oxidation state of TMB, as measured by absorbance at 450 nm, with a 20-fold reduction in oxidized TMB (P = 0.02). This result was consistent with an antioxidant mechanism for PIC1. In summary, PIC1 inhibits the peroxidase activity of myeloperoxidase in CF sputum likely via an antioxidant mechanism.

Innate immune response against an oomycete pathogen Aphanomyces invadans in common carp (Cyprinus carpio), a fish resistant to epizootic ulcerative syndrome

Infection with Aphanomyces invadans, also known as epizootic ulcerative syndrome, is a destructive disease of freshwater and brackishwater fishes. Although more than 130 species of fish have been confirmed to be susceptible to this disease, some of the commercially important fish species like common carp, milk fish and tilapia are reported to be resistant. Species that are naturally resistant to a particular disease, provide a potential model to study the mechanisms of resistance against that disease. In the present study, following experimental infection with A. invadans in common carp Cyprinus carpio, sequential changes in various innate immune parameters and histopathological alterations were monitored. Some of the studied innate immunity parameters viz. respiratory burst, alternative complement and total antiproteases activities of the infected common carp were higher compared to control fish, particularly at early stages of infection. On the other hand, some parameters such as myeloperoxidase, lysozyme and alpha-2 macroglobulin activities were not altered. Histopathological examination of the muscle at the site of injection revealed well developed granulomas at 12 days post infection, with subsequent regeneration of muscle fibers. From the results, it could be inferred that innate defense mechanisms of common carp are able to neutralize the virulence factors secreted by A. invadans, thereby, preventing its invasive spread and containing the infection. The results obtained here will help to better understand the mechanisms underlying resistance against A. invadans infection.

Fast Blue RR-Siloxane Derivatized Materials Indicate Wound Infection Due to a Deep Blue Color Development

There is a strong need for simple and fast methods for wound infection determination. Myeloperoxidase, an immune system-derived enzyme was found to be a suitable biomarker for wound infection. Hence, alkoxysilane-derivatized Fast Blue RR was immobilized via simple hydrolytic polymerization. The resulting enzyme-responsive siloxane layers were incubated with myeloperoxidase, wound fluid or hemoglobin. The reaction was monitored via HPLC measurements and the color development quantified spectrophotometrically. Myeloperoxidase was indeed able to oxidize immobilized Fast Blue RR leading to a blue colored product. No conversion was detected in non-infected wound fluids. The visible color changes of these novel materials towards blue enable an easy distinction between infected and non-infected wound fluids.

Combined effects of PLGA and vascular endothelial growth factor promote the healing of non-diabetic and diabetic wounds

Growth factor therapies to induce angiogenesis and thereby enhance the blood perfusion, hold tremendous potential to address the shortcomings of current impaired wound care modalities. Vascular endothelial growth factor stimulates (VEGF) wound healing via multiple mechanisms. Poly(lactic-co-glycolic acid) (PLGA) supplies lactate that accelerates neovascularization and promotes wound healing. Hence, we hypothesized that the administration of VEGF encapsulated in PLGA nanoparticles (PLGA-VEGF NP) would promote fast healing due to the sustained and combined effects of VEGF and lactate. In a splinted mouse full thickness excision model, compared with untreated, VEGF and PLGA NP, PLGA-VEGF NP treated wounds showed significant granulation tissue formation with higher collagen content, re-epithelialization and angiogenesis. The cellular and molecular studies revealed that PLGA-VEGF NP enhanced the proliferation and migration of keratinocytes and upregulated the expression of VEGFR2 at mRNA level. We demonstrated the combined effects of lactate and VEGF for active healing of non-diabetic and diabetic wounds.

FROM THE CLINICAL EDITOR

The study of wound healing has been under a tremendous amount of research over recent years. In diabetic wounds, vasculopathy leading to localized ischemia would often result in delayed 
wound healing. In this article, the authors encapsulated vascular endothelial growth factor stimulates (VEGF) in PLGA nanoparticles and studies the potential pro-healing effects. It was found that the combination of these two components provided synergistic actions for healing. The encouraging results should provide a basis for combination therapy in the future.

A rapid bioluminescence assay for measuring myeloperoxidase activity in human plasma

Myeloperoxidase (MPO) is a circulating cardiovascular disease (CVD) biomarker used to estimate clinical risk and patient prognosis. Current enzyme-linked immunosorbent assays (ELISA) for MPO concentration are costly and time-intensive. Here we report a novel bioluminescence assay, designated MPO activity on a polymer surface (MAPS), for measuring MPO activity in human plasma samples using the bioluminescent substrate L-012. The method delivers a result in under an hour and is resistant to confounding effects from endogenous MPO inhibitors. In a pilot clinical study, we compared MAPS and two clinical ELISAs using 72 plasma samples from cardiac catheterization patients. Results from parallel MAPS and ELISAs were concordant within 2±11 μg l(-1) MPO with similar uncertainty and reproducibility. Results between parallel MAPS and ELISA were in better agreement than those between independent ELISAs. MAPS may provide an inexpensive and rapid assay for determining MPO activity in plasma samples from patients with CVD or potentially other immune and inflammatory disorders.

PLGA nanoparticles loaded with host defense peptide LL37 promote wound healing

Wound treatment remains one of the most prevalent and economically burdensome healthcare issues in the world. Poly (lactic-co-glycolic acid) (PLGA) supplies lactate that accelerates neovascularization and promotes wound healing. LL37 is an endogenous human host defense peptide that modulates wound healing and angiogenesis and fights infection. Hence, we hypothesized that the administration of LL37 encapsulated in PLGA nanoparticles (PLGA-LL37 NP) promotes wound closure due to the sustained release of both LL37 and lactate. In full thickness excisional wounds, the treatment with PLGA-LL37 NP significantly accelerated wound healing compared to PLGA or LL37 administration alone. PLGA-LL37 NP-treated wounds displayed advanced granulation tissue formation by significant higher collagen deposition, re-epithelialized and neovascularized composition. PLGA-LL37 NP improved angiogenesis, significantly up-regulated IL-6 and VEGFa expression, and modulated the inflammatory wound response. In vitro, PLGA-LL37 NP induced enhanced cell migration but had no effect on the metabolism and proliferation of keratinocytes. It displayed antimicrobial activity on Escherichia coli. In conclusion, we developed a biodegradable drug delivery system that accelerated healing processes due to the combined effects of lactate and LL37 released from the nanoparticles.

Innate immune response of Indian major carp, Labeo rohita infected with oomycete pathogen Aphanomyces invadans

The fish pathogenic oomycete Aphanomyces invadans is the causative agent of epizootic ulcerative syndrome (EUS), a fish disease of international significance and reportable to the World Organisation for Animal Health. In spite of the current and potential impact of A. invadans infection on fisheries and aquaculture sectors of the world, very little is known about the host-A. invadans interactions. In the present study, following experimental infection with A. invadans in one of the Indian major carps, Labeo rohita, sequential changes in various innate immune parameters were monitored. The results indicated that at early stages of infection, no significant changes in any of the studied innate immune parameters were observed. However, at the advanced stages of infection from 6 to 12 days post infection (dpi), the respiratory burst and alternate complement activity were significantly higher whereas lysozyme, antiproteases and α-2 macroglobulin values were significantly lower than the control group and also from the infected group at earlier stages of infection. Since, the possibility of vaccination of fish against A. invadans appears remote due to difficulties in eliciting a specific antibody response, the information generated in the present study could be useful for developing strategies for improving resistance to A. invadans infection by stimulating the innate immunity through immunomodulation.