The impact of neoadjuvant chemotherapy on surgical outcomes following autologous and implant-based immediate breast reconstruction: A systematic review and meta-analysis

BACKGROUND

The impact of neoadjuvant chemotherapy (NACT) on the complication rate after implant-based and autologous breast reconstruction remains unclear. The aim of this study was to systematically review and perform a meta-analysis of previously published studies on immediate breast reconstruction (IBR) in breast cancer patients treated with NACT compared with controls.

METHODS

PubMed and EMBASE were searched to identify studies assessing the impact of NACT on major and minor complications after IBR. The primary effect measures were relative risk (RR), 95% confidence interval (95% CI), and p-value.

RESULTS

Eight studies comprising 51,731 patients were included in the meta-analysis. Of these, 5161 patients received NACT and 46,570 patients did not receive NACT. In regard to major complications, NACT did not statistically significant increase the rate of reconstructive failure (RR = 1.35, 95% CI = 0.96-1.91, p = 0.09), the rate of mastectomy skin-flap necrosis (RR = 1.39, 95% CI = 0.61-3.17, p = 0.44), or the rate of reoperation (RR = 1.09, 95% CI = 0.87-1.37, p = 0.45). Regarding minor complications, NACT did not significantly increase the rate of wound complications (RR = 1.05, 95% CI = 0.87-1.28, p = 0.62). In a subgroup analysis of implant-based breast reconstruction following NACT, single-stage direct-to-implant (DTI) had a significantly lower implant failure rate compared with two-staged tissue expander/implant (TE/I) (RR = 0.43, 95% CI = 0.26-0.71, p = 0.0011).

CONCLUSION

NACT did not increase the major or minor complication rate after IBR with either autologous tissue or implants. Thus, NACT and IBR should be considered safe procedures. The review of studies describing patients undergoing implant-based breast reconstruction following NACT could indicate that single-stage DTI was a safer procedure than two-staged TE/I. However, the association requires further evaluation.

Murine burn lesion model for studying acute and chronic wound infections

Acute wounds, such as thermal injury, and chronic wounds are challenging for patients and the healthcare system around the world. Thermal injury of considerable size induces immunosuppression, which renders the patient susceptible to wound infections, but also in other foci like the airways and urinary tract. Infected thermal lesions can progress to chronic wounds with biofilm making them more difficult to treat. While animal models have their limitations, murine wound models are still the best tool at the moment to identify strategies to overcome these challenges. Here, we present a murine burn model, which has been developed to study biofilm formation, the significance of wound healing, and for identifying novel treatment candidates. Investigating the effect of a thermal injury in mice, we observed that 48 h after introduction of the injury, the mice showed a reduction in polymorphonuclear neutrophil granulocytes (PMNs) and a reduced capacity for phagocytosis and oxidative burst. Regarding the chronic wound, Pseudomonas aeruginosa biofilm arrested wound healing and kept the wound in an inflammatory state, but suppressing PMN function by means of the PMN factor S100A8/A9, corresponding to observations in human venous leg ulcers. Monotherapy and dual treatment with S100A8/A9 and ciprofloxacin on P. aeruginosa biofilm-infected murine wounds have been investigated. In combination, S100A8/A9 and ciprofloxacin reduced the bacterial quantity, lowered the proinflammatory response, and increased anti-inflammatory cytokines after 4 days of treatment. When the treatment was prolonged, an additional prevention of resistance development was detected in all the dual-treated mice. In the present review, we provide data on using the murine model for research with the aim of better understanding pathophysiology of wounds and for identifying novel treatments for humans suffering from these lesions.

A Multidisciplinary Approach to Complex Dermal Sarcomas Ensures an Optimal Clinical Outcome

Primary dermal sarcomas (PDS) belong to a highly clinically, genetically and pathologically heterogeneous group of rare malignant mesenchymal tumours primarily involving the dermis or the subcutaneous tissue. The tumours are classified according to the mesenchymal tissue from which they originate: dermal connective tissue, smooth muscle or vessels. Clinically, PDS may mimic benign soft tissue lesions such as dermatofibromas, hypertrophic scarring, etc. This may cause substantial diagnostic delay. As a group, PDS most commonly comprises the following clinicopathological forms of dermal sarcomas: dermatofibrosarcoma protuberans (DFSP), atypical fibroxanthoma (AFX), dermal undifferentiated pleomorphic sarcoma (DUPS), leiomyosarcoma (LMS), and vascular sarcomas (Kaposi’s sarcoma, primary angiosarcoma, and radiation-induced angiosarcoma). This clinical entity has a broad spectrum regarding malignant potential; however, local aggressive behaviour in some forms causes surgical challenges. Preoperative, individualised surgical planning with complete free margins is pivotal along with a multidisciplinary approach and collaboration across highly specialised surgical and medical specialties. The present review gives a structured overview of the most common forms of dermal sarcomas including surgical recommendations and examples for advanced reconstructions as well as the current adjunctive medical treatment strategies. Optimal aesthetic and functional outcomes with low recurrence rates can be achieved by using a multidisciplinary approach to complex dermal sarcomas. In cases of extended local tumour invasion in dermal sarcomas, advanced reconstructive techniques can be applied, and the interdisciplinary microsurgeon should be an integral part of the sarcoma board.

Subungual Onycholemmal Cysts: A Case Report

Subungual onycholemmal cysts (SOCs) are rare nail abnormalities. The clinical findings vary and include onychodystrophy, ridging, nail bed pigmentation, and thickening, but most often SOCs do not cause any symptoms and are accidental findings. In this case report, we present a case of a woman with pigmentation of the toenail, suspect for melanoma. Surprisingly, the histopathological examination showed SOCs. We discuss the histological features of SOCs, etiology, and differential diagnoses.

Synergistic effect of immunomodulatory S100A8/A9 and ciprofloxacin against Pseudomonas aeruginosa biofilm in a murine chronic wound model

The majority of chronic wounds are associated with bacterial biofilms recalcitrant to antibiotics and host responses. Immunomodulatory S100A8/A9 is suppressed in Pseudomonas aeruginosa biofilm infected wounds. We aimed at investigating a possible additive effect between S100A8/A9 and ciprofloxacin against biofilms.

MATERIALS/METHODS

Thirty-two mice were injected with alginate-embedded P. aeruginosa following a third-degree burn. The mice were randomized into four groups receiving combination ciprofloxacin and S100A8/A9 or monotherapy ciprofloxacin, S100A8/A9 or a placebo and evaluated by host responses and quantitative bacteriology in wounds. In addition, in vitro checkerboard analysis was performed, with P. aeruginosa and ascending S100A8/A9 and ciprofloxacin concentrations.

RESULTS

S100A8/A9 augmented the effect of ciprofloxacin in vivo by lowering the bacterial quantity compared to the placebo arm and the two monointervention groups (P < 0.0001). S100A8 and 100A9 were increased in the double-treated group as compared to the monointervention groups (P = 0.032, P = 0.0023). Tissue inhibitor of metalloproteinases-1 and keratinocyte\chemokine chemoattractant-1 were increased in the double-intervention group compared to the S100A8/A9 group (P = 0.050, P = 0.050). No in vitro synergism was detected.

CONCLUSION

The observed ciprofloxacin-augmenting effect of S100A8/A9 in vivo was not confirmed by checkerboard analysis, indicating dependence on host cells for the S100A8/A9 effect. S100A8/A9 and ciprofloxacin is a promising therapy for optimizing chronic wound treatment.

Adjunctive S100A8/A9 Immunomodulation Hinders Ciprofloxacin Resistance in Pseudomonas aeruginosa in a Murine Biofilm Wound Model

Objective

Pseudomonas aeruginosa is known to contribute to the pathogenesis of chronic wounds by biofilm-establishment with increased tolerance to host response and antibiotics. The neutrophil-factor S100A8/A9 has a promising adjuvant effect when combined with ciprofloxacin, measured by quantitative bacteriology, and increased anti- and lowered pro-inflammatory proteins. We speculated whether a S100A8/A9 supplement could prevent ciprofloxacin resistance in infected wounds.

Method

Full-thickness 2.9cm²-necrosis was inflicted on 32 mice. On day 4, P.aeruginosa in seaweed alginate was injected sub-eschar to mimic a mono-pathogenic biofilm. Mice were randomized to receive ciprofloxacin and S100A8/A9 (n=14), ciprofloxacin (n=12) or saline (n=6). Half of the mice in each group were euthanized day 6 and the remaining day 10 post-infection. Mice were treated until sacrifice. Primary endpoint was the appearance of ciprofloxacin resistant P.aeruginosa. The study was further evaluated by genetic characterization of resistance, means of quantitative bacteriology, wound-size and cytokine-production.

Results

Three mice receiving ciprofloxacin monotherapy developed resistance after 14 days. None of the mice receiving combination therapy changed resistance pattern. Sequencing of fluoroquinolone-resistance determining regions in the ciprofloxacin resistant isolates identified two high-resistant strains mutated in gyrA C248T (MIC>32µg/ml) and a gyr B mutation was found in the sample with low level resistance (MIC=3µg/ml). Bacterial densities in wounds were lower in the dual treated group compared to the placebo group on both termination days.

Conclusion

This study supports the ciprofloxacin augmenting effect and indicates a protective effect in terms of hindered ciprofloxacin resistance of adjuvant S100A8/A9 in P.aeruginosa biofilm infected chronic wounds.

Immune Responses to Pseudomonas aeruginosa Biofilm Infections

Pseudomonas aeruginosa is a key pathogen of chronic infections in the lungs of cystic fibrosis patients and in patients suffering from chronic wounds of diverse etiology. In these infections the bacteria congregate in biofilms and cannot be eradicated by standard antibiotic treatment or host immune responses. The persistent biofilms induce a hyper inflammatory state that results in collateral damage of the adjacent host tissue. The host fails to eradicate the biofilm infection, resulting in hindered remodeling and healing. In the present review we describe our current understanding of innate and adaptive immune responses elicited by P. aeruginosa biofilms in cystic fibrosis lung infections and chronic wounds. This includes the mechanisms that are involved in the activation of the immune responses, as well as the effector functions, the antimicrobial components and the associated tissue destruction. The mechanisms by which the biofilms evade immune responses, and potential treatment targets of the immune response are also discussed.

Don't Judge a Tumor by Its Biopsy!

Trichoblastomas (TBs) are extremely rare, benign hair germ tumors that can mimic basal cell carcinoma (BCC). They usually arise on the head or neck and have a potential for malignant transformation, albeit it is rare. We report a case of giant TB on the forehead of a 75-year-old otherwise healthy woman. Since the age of 20 she reported a bulge on her forehead, in which a superficial-looking wound had now developed. Initially a dermatologist biopsied the tumor suspecting a BCC, which the histological analyses confirmed. The patient was then referred to the Department of Plastic Surgery for complete excision of the carcinoma, including the large frontal bulge. Surprisingly, the concluding pathology report changed the diagnosis from a BCC to a TB. Current management of most skin lesions relies on the histopathological subtype of a single punch biopsy. Many benign and malignant dermatological entities may mimic BCC, and therefore misdiagnosis can lead to either unnecessary excision or delayed treatment of metastatic disease. Mimics may include various types of nonneoplastic processes, benign adnexal tumors, including TB, or cutaneous carcinomas with basaloid features. A single punch biopsy is not always adequate in making the correct diagnosis. Although it is considered the gold standard, the clinical assessment is just as important. Due to its potential for malignant transformation, it is recommended to excise TB with negative margins.

Renal cell carcinoma presenting as a tumor on the scalp: A case report

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Skin metastases from renal cell carcinomas are rare.

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Skin metastases might have a vascularized appearance.

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Metastasis to the skin is associated with a poor prognosis.

Introduction

Renal cell carcinoma (RCC) is often diagnosed as an incidental finding on imaging studies and about a fourth of patients have metastases by the time of diagnosis. RCC is known to metastasize widely but cutaneous metastases are considered uncommon and are rarely the presenting symptom of RCC. We present a case of RCC presenting with a tumor on the scalp.

Case

A 65-year-old healthy man presented with a 9-month history of a growing mass on the scalp. Clinical examination revealed a pulsating, highly vascularized tumor that was excised. Histopathological findings were consistent with a metastasis from a renal cell carcinoma. Further investigations revealed a 13 cm kidney tumor with metastases to the lungs and mediastinum.

Discussion

Cutaneous metastasis from RCC is uncommon and is rarely the initial symptom of RCC. The lesions often have a vascularized appearance and may be clinically confused with other vascular tumors. Skin metastasis is a sign of advanced disease and prognosis is poor.

Conclusion

An occult RCC may present with a skin lesion. Skin metastasis from RCC is an important differential diagnosis in tumors with a vascular appearance, especially in patients with a previous history of RCC.

Long-term evaluation of climatotherapy for psoriasis

Climatotherapy (CT) is a treatment with immediate high clearance rate for chronic psoriasis, but evidence of long-term effects is scarce. Assessment of the impact of a single CT treatment on disease activity and quality of life was carried out at 4- to 6-month follow-ups. A prospective study of patients with psoriasis undergoing 4 weeks of CT in Israel describes long-term outcomes of CT. Psoriasis Area Severity Index (PASI) and Dermatology Life Quality Index (DLQI) scores were assessed before CT and at an average of 5 months after return. Assessment of the eligibility for CT takes place twice a year. A total of 49 patients (28/21 M/F) participated. Pretreatment PASI was 2.6 to 18.7 (mean 8.1 ± 3.8) vs control PASI 0 to 16.9 (mean 5 ± 2.8), (P < .0001). Mean ΔPASI was 3.2 (39.5% reduction). PASI 75 was achieved by 11/49 patients; 10/49 had increased PASI. The mean DLQI score was 16.1 (range 2-30); 10.6 at follow-up (range 0-28), and 33 patients achieved DLQI minimal clinically important difference (P < .0001). Age, sex, number of previous CT, and duration of observation period did not affect endpoints. CT and unmonitored self-treatment induces PASI 75 in one-fifth patients at follow-up 4 to 6 months later. Six of 10 patients report a clinically important improvement of patients' quality of life as measured by DLQI.

Unusual Presentation of Cutaneous Spindle Cell Squamous Cell Carcinoma: A Case Report

Cutaneous spindle cell squamous cell carcinoma (SpSCC) is a rare and often aggressive subtype of squamous cell carcinoma (SCC), which usually appears in sun-exposed areas, in areas that have received prior ionizing radiation, or in immunosuppressed individuals. SpSCCs are histologically characterized by keratinocytes infiltrating the dermis as single cells with elongated nuclei rather than as cohesive nests or islands and, in contrast to conventional SCC, are lacking features of keratinization. Immunohistochemical studies are useful to distinguish SpSCC from other spindle cell neoplasms, such as spindle cell/desmoplastic melanoma, cutaneous leiomyosarcoma, and atypical fibroxanthoma. We present a rare case of a patient with SpSCC in the gluteal region with regional lymph node metastasis. The patient was treated with wide excision of the tumor, inguinal lymph node dissection, and adjuvant radiotherapy. Cutaneous SpSCC is clinically similar to conventional SCC but can demonstrate more aggressive behavior. This case is rare since it was localized in the gluteal region of an otherwise healthy man.

Concurrent sarcoidal granulomas and melanoma micrometastasis in a sentinel node - a case report

Incidental findings of non-caseating granulomas and metastasis in sentinel lymph nodes are rare but cause clinical challenges. We report a case of coinciding unexpected asymptomatic lymphoid sarcoidosis and a micrometastasis in a sentinel node of a patient, who was newly diagnosed with 2.0 mm thick melanoma on the left calf.

Uncontrolled gelatin degradation in non-healing chronic wounds

OBJECTIVE

To compare matrix metalloproteinase (MMP)-9 and the antiproteinase tissue inhibitor of metalloproteinases (TIMP)-1 in wound fluids and sera from patients with chronic non-healing or acute healing wounds. In addition, the functional consequences on MMP-9 activity and general gelatinase activity were assessed.

METHOD

In this observational study, samples were collected from patients with venous leg ulcers (VLUs), patients with type 2 diabetes with neuropathic foot ulcers (DFUs), and from another cohort of VLU patients with sterile split-thickness skin graft donor sites after autologous skin grafting, serving as healing control wounds. MMP-9 and TIMP-1 concentrations were determined by enzyme-linked immunosorbent assays. MMP-9 and gelatinase activities were determined in wound fluids in subsets of the patients.

RESULTS

A total of 24 patients took part in the study. No significant differences in MMP-9 wound fluid levels were found among the three groups. TIMP-1 levels were markedly and significantly lower in the two chronic wound groups resulting in a severely unbalanced MMP-9/TIMP-1 ratio, especially notable in the VLU group and possibly in the elevated endogenous MMP-9 activity (p<0.01) compared with the acute wound fluids. At least 20% of the chronic wound fluids displayed atypical patterns on gelatin zymography and showed high general gelatinase activity that was not inhibited by either TIMP-1 or by a gelatinase inhibitor (AG3340). MMP-9 levels were higher in the sera of the patients with type 2 diabetes.

CONCLUSION

We hypothesise that non-MMP proteinases contribute to matrix destruction in a significant number of chronic wounds. Blocking the excessive MMP-9 activity may be insufficient to normalise wound healing. The reasons and effects of the very low TIMP-1 levels in chronic wounds need further clarification.

Anogenital Verrucous Carcinoma-A case report

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Verrucous carcinoma (VC) is a variant of squamous cell carcinoma.

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Anogenital VC is a rare condition, which clinically presents as common genital warts.

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Early recognition of VC and radical excision is crucial due to local destruction of tissue.

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Recurrence of VC is not uncommon.

Introduction

Verrucous carcinoma is an uncommon variant of low-grade squamous cell malignancy with a low malignant potential but a high risk of recurrence.

Presentation of case

We report a case of a Human Papilloma Virus negative local verrucous carcinoma in the perianal area of a 45-year old otherwise healthy female. The tumor presented clinically as a persistent genital wart not responding to usual dermatologic local therapy. The patient was referred to the Department of Plastic Surgery and Breast Surgery after primary excision in a private practice setting of a general surgeon. Three months later, further excision revealed local lichen sclerosus inflammatory changes in close proximity to the excision scar.

Discussion

Due to the low occurrence of verrucous carcinoma in the perianal area, no guidelines are available for the management of this disease. Conflicting reports on the ethiology and the nomenclature and classifications of verrucous carcinomas exist.

Conclusion

Avoid pitfalls in the diagnosis of a rare variant of squamous cell cancer with a high recurrence ratio: Common genital warts not responding to ordinary local antimitotic Podophyllotoxin treatment require biopsy to exclude verrucous carcinoma. Follow-up is recommended at a 3–6 months interval due to the relative high risk of relapse.

Chronic Pseudomonas aeruginosa biofilm infection impairs murine S100A8/A9 and neutrophil effector cytokines-implications for delayed wound closure?

The impact of Pseudomonas aeruginosa biofilm infections in chronic wounds and clinical implication for healing is receiving increased attention. However, the pathophysiology of host/pathogen interplay is not fully understood. By further revealing the mechanisms, necessary new treatment strategies may be identified. Since the background for chronic wounds is diverse, representative animal models are important. We assessed host response and spontaneous wound closure in the relatively resistant C3H/HeN and the susceptible BALB/c mouse strain. Full-thickness burn wounds were inflicted in 108 mice. Pseudomonas aeruginosa biofilm (106 colony forming units) was injected subcutaneously in 72 mice, euthanised day 4, 7 or 10 days post-infection. Wounds were analysed for neutrophil host response markers: S100A8/A9, keratinocyte-derived chemokine and granulocyte-colony stimulating factor. Total peripheral blood leucocyte and polymorphonuclear count were assessed in parallel. Histopathology evaluated wound inflammatory burden. Photoplanimetry described macroscopical wound closure. Stable chronic wound infection was established in all challenged mice. Pseudomonas aeruginosa biofilm suppressed neutrophil host response in wounds. C3H/HeN mice achieved earlier systemic inflammatory control and healed faster than BALB/c mice. Pseudomonas aeruginosa biofilms perturb host defence thereby inducing a steady state of chronic infection which may impair wound healing. These results indicate therapeutic options for immune modulation of biofilm-infected wounds.

Pseudomonas aeruginosa biofilm hampers murine central wound healing by suppression of vascular epithelial growth factor

Biofilm-infected wounds are clinically challenging. Vascular endothelial growth factor and host defence S100A8/A9 are crucial for wound healing but may be suppressed by biofilms. The natural course of Pseudomonas aeruginosa biofilm infection was compared in central and peripheral zones of burn-wounded, infection-susceptible BALB/c mice, which display delayed wound closure compared to C3H/HeN mice. Wounds were evaluated histopathologically 4, 7 or 10 days post-infection. Photoplanimetry evaluated necrotic areas. P. aeruginosa biofilm suppressed vascular endothelial growth factor levels centrally in BALB/c wounds but increased peripheral levels 4-7 days post-infection. Central zones of the burn wound displayed lower levels of central vascular endothelial growth factor as observed 4 and 7 days post-infection in BALB/c mice compared to their C3H/HeN counterparts. Biofilm suppressed early, centrally located S100A8/A9 in BALB/c and centrally and peripherally later on in C3H/HeN wounds as compared to uninfected mice. Peripheral polymorphonuclear-dominated inflammation and larger necrosis were observed in BALB/c wounds. In conclusion, P. aeruginosa biofilm modulates wounds by suppressing central, but inducing peripheral, vascular endothelial growth factor levels and reducing host response in wounds of BALB/c mice. This suppression is detrimental to the resolution of biofilm-infected necrosis.

Immune Modulating Topical S100A8/A9 Inhibits Growth of Pseudomonas aeruginosa and Mitigates Biofilm Infection in Chronic Wounds

Pseudomonas aeruginosa biofilm maintains and perturbs local host defense, hindering timely wound healing. Previously, we showed that P. aeruginosa suppressed S100A8/A9 of the murine innate host defense. We assessed the potential antimicrobial effect of S100A8/A9 on biofilm-infected wounds in a murine model and P. aeruginosa growth in vitro. Seventy-six mice, inflicted with a full-thickness burn wound were challenged subcutaneously (s.c.) by 10⁶ colony-forming units (CFUs) of P. aeruginosa biofilm. Mice were subsequently randomized into two treatment groups, one group receiving recombinant murine S100A8/A9 and a group of vehicle controls (phosphate-buffered saline, PBS) all treated with s.c. injections daily for up to five days. Wounds were analyzed for quantitative bacteriology and contents of key inflammatory markers. Count of blood polymorphonuclear leukocytes was included. S100A8/A9-treatment ameliorated wound infection, as evaluated by quantitative bacteriology (p ≤ 0.05). In vitro, growth of P. aeruginosa was inhibited dose-dependently by S100A8/A9 in concentrations from 5 to 40 μg/mL, as determined by optical density-measurement (OD-measurement) and quantitative bacteriology. Treatment slightly augmented key inflammatory cytokine Tumor Necrosis Factor-α (TNF-α), but dampened interferon-γ (IFN-γ) levels and blood polymorphonuclear count. In conclusion, topical S100A8/A9 displays remarkable novel immune stimulatory and anti-infective properties in vivo and in vitro. Importantly, treatment by S100A8/A9 provides local infection control. Implications for a role as adjunctive treatment in healing of chronic biofilm-infected wounds are discussed.

The phagocytic fitness of leucopatches may impact the healing of chronic wounds

Chronic non-healing wounds are significantly bothersome to patients and can result in severe complications. In addition, they are increasing in numbers, and a challenging problem to the health-care system. Handling of chronic, non-healing wounds can be discouraging due to lack of improvement, and a recent explanation can be the involvement of biofilm infections in the pathogenesis of non-healing wounds. Therefore, new treatment alternatives to improve outcome are continuously sought-after. Autologous leucopatches are such a new, adjunctive treatment option, showing promising clinical effects. However, the beneficial effect of the patches are not understood fully, although a major contribution is believed to be from the release of stimulating growth factors from activated thrombocytes within the leucopatch. Because the leucopatches also contain substantial numbers of leucocytes, the aim of the present study was to investigate the activity of the polymorphonuclear neutrophils (PMNs) within the leucopatch. By means of burst assay, phagocytosis assay, migration assay, biofilm killing assay and fluorescence in-situ hybridization (FISH) assay we showed significant respiratory burst in PMNs, active phagocytosis and killing of Pseudomonas aeruginosa by the leucopatch. In addition, bacterial-induced migration of PMNs from the leucopatch was shown, as well as uptake of P. aeruginosa by PMNs within the leucopatch. The present study substantiated that at least part of the beneficial clinical effect in chronic wounds by leucopatches is attributed to the activity of the PMNs in the leucopatch.

Low efficacy of tobramycin in experimental Staphylococcus aureus endocarditis

The empiric treatment of infective endocarditis (IE) varies widely and, in some places, a regimen of penicillin in combination with an aminoglycoside is administered. The increasing incidence of Staphylococcus aureus IE, poor tissue penetration by aminoglycosides and low frequency of penicillin-susceptible S. aureus may potentially lead to functional tobramycin monotherapy. Therefore, this study aimed to evaluate tobramycin monotherapy in an experimental S. aureus IE rat model. Catheter-induced IE at the aortic valves were established with S. aureus (NCTC 8325-4) and rats were randomised into untreated (n = 22) or tobramycin-treated (n = 13) groups. The treatment group received tobramycin once-daily. Animals were evaluated at 1 day post infection (DPI), 2 DPI or 3 DPI. Quantitative bacteriology and cytokine expression were measured for valves, myocardium and serum. A decrease of bacterial load was observed in valves and the spleens of the treated (n = 6) compared to the untreated group at 2 DPI (n = 8) (p ≤ 0.02 and p ≤ 0.01, respectively), but not at 3 DPI (n = 7). Quantitative bacteriology in the myocardium was not different between the groups. Keratinocyte-derived chemokine (KC) in the aortic valves was significantly reduced at 2 DPI in the tobramycin-treated group (p ≤ 0.03). However, the expression of interleukin (IL)-1b, IL-6 and granulocyte-colony stimulating factor (G-CSF) in the valves was not different between the two groups. In the myocardium, a significant reduction in IL-1b was observed at 2 DPI (p ≤ 0.001) but not at 3 DPI. Tobramycin as functional monotherapy only reduced bacterial load and inflammation transiently, and was insufficient in most cases of S. aureus IE.

Animal models to evaluate bacterial biofilm development

Medical biofilms have attracted substantial attention especially in the past decade. Animal models are contributing significantly to understand the pathogenesis of medical biofilms. In addition, animal models are an essential tool in testing the hypothesis generated from clinical observations in patients and preclinical testing of agents showing in vitro antibiofilm effect. Here, we describe three animal models - two non-foreign body Pseudomonas aeruginosa biofilm models and a foreign body Staphylococcus aureus model.

Bead-size directed distribution of Pseudomonas aeruginosa results in distinct inflammatory response in a mouse model of chronic lung infection

Chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) patients is characterized by biofilms, tolerant to antibiotics and host responses. Instead, immune responses contribute to the tissue damage. However, this may depend on localization of infection in the upper conductive or in the peripheral respiratory zone. To study this we produced two distinct sizes of small alginate beads (SB) and large beads (LB) containing P. aeruginosa. In total, 175 BALB/c mice were infected with either SB or LB. At day 1 the quantitative bacteriology was higher in the SB group compared to the LB group (P < 0·003). For all time-points smaller biofilms were identified by Alcian blue staining in the SB group (P < 0·003). Similarly, the area of the airways in which biofilms were identified were smaller (P < 0·0001). A shift from exclusively endobronchial to both parenchymal and endobronchial localization of inflammation from day 1 to days 2/3 (P < 0·05), as well as a faster resolution of inflammation at days 5/6, was observed in the SB group (P < 0·03). Finally, both the polymorphonuclear neutrophil leucocyte (PMN) mobilizer granulocyte colony-stimulating factor (G-CSF) and chemoattractant macrophage inflammatory protein-2 (MIP-2) were increased at day 1 in the SB group (P < 0·0001). In conclusion, we have established a model enabling studies of host responses in different pulmonary zones. An effective recognition of and a more pronounced host response to infection in the peripheral zones, indicating that increased lung damage was demonstrated. Therefore, treatment of the chronic P. aeruginosa lung infection should be directed primarily at the peripheral lung zone by combined intravenous and inhalation antibiotic treatment.

S100A8/A9 deficiency in nonhealing venous leg ulcers uncovered by multiplexed antibody microarray profiling

BACKGROUND

Knowledge on the underlying mechanisms for nonhealing chronic wounds is fragmentary.

OBJECTIVES

To increase our understanding of the pathogenesis, the relationship between healing ability and a large panel of proteins was studied using a specially designed wound-healing antibody-based microarray.

METHODS

Wound fluid from nondiabetic patients with nonhealing venous leg ulcers was compared with that from patients with healing open granulating acute wounds. The high-throughput method enabled simultaneous measurement of the relative levels of 48 different proteins representing major categories of wound-healing modulators.

RESULTS

Unexpectedly, several of the examined proteins, including various proinflammatory cytokines, proteinases and antiproteinases, were not significantly (P>0·001) changed in chronic wound fluid. For example, levels of matrix metalloproteinase-9 and one of its substrates type IV collagen were similar in the two groups. The wound fluid samples displayed similar degrees of fragmentation of fibronectin by Western blot analysis and the total fibronectin levels were doubled (P<0·001) in chronic compared with acute wounds. The increased fibronectin originated from α-smooth muscle actin-positive myofibroblasts and not from the circulation. S100A8/A9 was the sole protein that was reduced (P<0·001) in wound fluid from venous ulcers [median 226 μg mL(-1) (interquartile range 213-278)] compared with healing wounds [455 μg mL(-1) (382-504)], probably reflecting a difference in inflammatory cell composition.

CONCLUSION

The molecular anomalies in chronic wounds are more subtle than the current paradigm and neither excessive proteinase activity nor deficiencies of examined extracellular matrix proteins, growth factors or angiogenic/angiostatic factors appear to contribute significantly to the nonhealing state of venous leg ulcers.