Safety and efficacy of single insertion accelerated MR-image guided brachytherapy following chemo-radiation in locally advanced cervix cancer: modifying our EMBRACE during the COVID pandemic

BACKGROUND

Utero-vaginal brachytherapy (BT) is an irreplaceable care component for the curative treatment of locally advanced cervix cancer (LACC). Magnetic Resonance Imaging (MRI)-image guided adaptive BT (IGABT) using the GYN-GEC-ESTRO EMBRACE guidelines is the international care standard. Usually following chemo-radiation therapy (CRT), IGABT has high proven utility in LACC but requires significant health system resources. Timely access was disrupted by the COVID-19 pandemic which challenged us to re-design our established IGABT care pathway.

METHODS

From April 2020 consecutive patients with LACC were enrolled after CRT in a single arm exploratory non-inferiority study of a modified IGABT (mIGABT) protocol. This delivered an iso-effective IGABT dose (39.3 Gy: EQD2: α/β10Gy concept) over a 24-h period during a single overnight hospitalisation.

RESULTS

Fourteen LACC patients received mIGABT from April 2020 to March 2022. Median age was 62.5 years (37-82 years). LACC histology was primary squamous (9/14) or adeno-carcinoma (5/14). International Federation of Gynaecology and Obstetrics (FIGO) 2018 stages ranged from IB1/2 (N = 3), IIA1/IIB (5), IIIB (2), IIIC1/2 (4) with mean ± standard deviation (SD) gross tumour volume-at-diagnosis (GTV_D) of 37.7 cc ± 71.6 cc. All patients achieved complete metabolic, clinical, and cytologic cancer response with CRT and IGABT. High-risk HPV was cleared by 6-months. Complete MRI-defined cancer response before mIGABT (GTV_Fx1) was seen in 77% of cases (10/13). Only two women developed metastatic disease and one died at 12-months; 13 patients were alive without cancer at mean 20.3 ± 7.2 months follow-up. Actuarial 2-year overall survival was 93%. Compared with our pre-COVID IGABT program, overall mIGABT cost-saving in this cohort was USD 22,866. Prescribed dose covered at least 90% (D90) of the entire cervix and any residual cancer at time of BT (HRCTV_D90: high-risk clinical target volume) with 3-fractions of 8.5 Gy delivered over 24-h (22.8 ± 1.7 h). Total treatment time including CRT was 38 days. The mIGABT schedule was well tolerated and the entire cohort met EMBRACE recommended (EQD2: α/β10Gy) combined HRCTV_D90 coverage of 87.5 ± 3.7 Gy. Similarly, organ-at-risk (OAR) median: interquartile range D2cc constraints (EQD2: α/β3Gy) were EMBRACE compliant: bladder (65.9 Gy: 58.4-72.5 Gy), rectum (59.1 Gy: 55.7-61.8 Gy), and sigmoid colon (54.6 Gy: 50.3-58.9 Gy). ICRU recto-vaginal point dose was significantly higher (75.7 Gy) in our only case of severe (G4) pelvic toxicity.

CONCLUSIONS

This study demonstrated the utility of mIGABT and VMAT CRT in a small cohort with LACC. Loco-regional control was achieved in all cases with minimal emergent toxicity. Single insertion mIGABT was logistically efficient, cost-saving, and patient-centric during the COVID-19 pandemic.

Co-Localization of Macrophage Inhibitory Factor and Nix in Skeletal Muscle of the Aged Male Interleukin 10 Null Mouse

Chronic inflammation is associated with muscle weakness and frailty in older adults. The antagonistic cross-talk between macrophage migration inhibitory factor (Mif), an anti-apoptotic cytokine and NIP3-like protein X (Nix), a pro-apoptotic mitochondrial protein, may play a role in mitochondrial free radical homeostasis and inflammatory myopathies. We examined Nix-Mif interaction in inflammation and aging using young and old, IL-10tm/tm (a rodent model of chronic inflammation) and C57BL/6 mice. In this study, we observed that Nix and Mif were co-localized in skeletal muscles of aged and inflamed mice. We show an inflammation- and age-related association between Nix and Mif gene expression, with the strongest positive correlation observed in old IL-10tm/tm skeletal muscles. The IL-10tm/tm skeletal muscles also had the highest levels of oxidative stress damage. These observations suggest that Nix-Mif cross-talk may play a role in the interface between chronic inflammation and oxidative stress in aging skeletal muscles.

Measures of socioeconomic status and self-reported glaucoma in the U.K. Biobank cohort

PURPOSE

To determine ocular, demographic, and socioeconomic associations with self-reported glaucoma in the U.K. Biobank.

METHODS

Biobank is a study of U.K. residents aged 40-69 years registered with the National Health Service. Data were collected on visual acuity, intraocular pressure (IOP), corneal biomechanics, and questionnaire from 112,690 participants. Relationships between ocular, demographic, and socioeconomic variables with reported diagnosis of glaucoma were examined.

RESULTS

In all, 1916 (1.7%) people in U.K. Biobank reported glaucoma diagnosis. Participants reporting glaucoma were more likely to be older (mean 61.4 vs. 56.7 years, P<0.001) and male (2.1% vs. 1.4%, P=0.001). The rate of reported glaucoma was significantly higher in Black (3.28%, P<0.001) and Asian (2.14%, P=0.009) participants compared with White participants (1.62%, reference). Cases of reported glaucoma had a higher mean IOP (18 mm Hg both eyes, P<0.001), lower corneal hysteresis (9.96 right eye, 9.89 left eye, P<0.001), and lower visual acuity (0.09 logMAR right eye, 0.08 logMAR left eye, P<0.001) compared with those without (16 mm Hg both eyes, hysteresis 10.67 right eye, 10.63 left eye, 0.03 logMAR right eye, 0.02 logMAR left eye). The mean Townsend deprivation index was -0.72 for those reporting glaucoma and -0.95 for those without (P<0.001), indicating greater relative deprivation in those reporting glaucoma. Multivariable logistic regression showed that people in the lowest income group (<£18,000/year) were significantly more likely to report a diagnosis of glaucoma compared with any other income level (P<0.01). We observed increasing glaucoma risk across the full range of income categories, with highest risk among those of lowest income, and no evidence of a threshold effect.

CONCLUSIONS

In a large U.K. cohort, individuals reporting glaucoma had more adverse socioeconomic characteristics. Study of the mechanisms explaining these effects may aid our understanding of health inequality and will help inform public health interventions.

Suppression of in vitro proliferative scar fibroblast contraction by interferon alfa-2b

Increased fibroblast activity and collagen production have been observed frequently in proliferative scars. Previous studies have demonstrated that interferons suppress collagen production by means of normal, keloid, and hypertrophic scar-derived fibroblasts. The fibroblast-populated collagen lattice is an in vitro model used to study fibroblast function. We used fibroblast-populated collagen lattices to evaluate the effect of interferon on fibroblasts harvested from normal human skin, human keloid, and hypertrophic scar tissues. Human recombinant interferon alfa-2b (1000 IU/ml) was added to the culture media. The collagen gel, prepared from rat tail tendon bundles, was overlaid with 5 x 10(4) fibroblast cells. Keloid fibroblast-populated collagen lattices showed the highest contraction. Contraction in all the groups appeared suppressed by interferon alfa-2b during the first 72 hours of study (p < 0.05). The reduction in fibroblast-populated collagen lattice contraction by interferon alfa-2b was similar among the groups. The contractile properties of fibroblasts taken from normal human skin, keloids, and hypertrophic scars in this in vitro study were suppressed by interferon alfa-2b. This suggested that interferon alfa-2b may be beneficial for the treatment of proliferative scars.

A novel hydrogel-collagen composite improves functionality of an injectable extracellular matrix

Cellular transplantation is now closer to becoming a practical clinical strategy to repair, regenerate or restore the function of skin, muscle, nerves and pancreatic islets. In this study we sought to develop a simple injectable collagen matrix that would preserve the normal cellular organization of skin cells. Three different scaffolds were created and compared: collagen-glycosaminoglycan (GAG) scaffolds, crosslinked collagen-GAG scaffolds without polyvinyl alcohol (PVA) and crosslinked collagen-GAG scaffolds containing PVA hydrogel. Importantly, all scaffolds were found to be non-cytotoxic. PVA-containing gels exhibited a higher tensile strength (P<0.05), faster fibril formation (P<0.001) and reduced collagenase digestion (P<0.01) compared with other gels. Free floating fibroblast-populated, PVA-borate scaffolds resisted contraction over a 10 day period (P<0.001). The fibroblast-populated scaffolds containing PVA demonstrated a 3-fold reduction in cellularity over 10 days compared with the control gels (P<0.001). Multicellular skin substitutes containing PVA-borate networks display a linear cellular organization, reduced cellularity and the formation of a keratinized epidermis that resembles normal skin. In conclusion, these data underscore the multifunctionality of a simple PVA-borate-collagen matrix as an injectable composite for tissue engineering or cell transplantation.

Recognition of the alternatively spliced segments of fibronectin by the RCJ 3.1C5.18 chondrocytic rat cell line

OBJECTIVES

To define, for the C5.18 chondrocyte-restricted rat cell line, (1) the capacities for recognition of alternatively spliced segments of the adhesion protein fibronectin (FN), (2) the integrin subunits required for such recognition, and (3) differences in such FN recognition vs the multipotential chondroprogenitor line, RCJ 3.1.

METHODS

C5.18 and RCJ 3.1 cells were tested for their capacities to adhere to recombinant alternatively spliced segments of rat FN, presented on plastic surfaces either in isolation or in partial FNs spanning the 7th through 15th type III repeats (III7-15 FNs). The effects on such adhesion of cations and integrin subunit-specific antibodies were tested.

RESULTS

Despite significant augmentation in chondrocyte-specific gene expression in C5.18 relative to the RCJ 3.1 cells, the two lines exhibited similar recognition of FN spliced segments and partial isoforms. Specifically, both lines adhered to the extra type III repeat A (EIIIA) and V, but not extra type III repeat B (EIIIB), segments. There were different cation and integrin subunit requirements for adhesion to EIIIA vs V segments, and only the V segment was recognized in the context of a III7-15 FN. Such recognition was mediated via a "second" arginine-glycine-aspartic acid (RGD) sequence that is present in the V95 subsegment in rat, but not human, FN.

CONCLUSION

The chondrocyte lineage-committed C5.18 cell line, similar to its multipotential chondroprogenitor, RCJ 3.1, recognizes the "cartilage-restricted" EIIIA and V segments of FN with cation, integrin, and molecular context requirements that are specific to each of these segments.

Dopamine receptor contribution to the action of PCP, LSD and ketamine psychotomimetics

Although phencyclidine and ketamine are used to model a hypoglutamate theory of schizophrenia, their selectivity for NMDA receptors has been questioned. To determine the affinities of phencyclidine, ketamine, dizocilpine and LSD for the functional high-affinity state of the dopamine D2 receptor, D2High, their dissociation constants (Ki) were obtained on [3H]domperidone binding to human cloned dopamine D2 receptors. Phencyclidine had a high affinity for D2High with a Ki of 2.7 nM, in contrast to its low affinity for the NMDA receptor, with a Ki of 313 nM, as labeled by [3H]dizocilpine on rat striatal tissue. Ketamine also had a high affinity for D2High with a Ki of 55 nM, an affinity higher than its 3100 nM Ki for the NMDA sites. Dizocilpine had a Ki of 0.3 nM at D2High, but a Kd of 1.8 nM at the NMDA receptor. LSD had a Ki of 2 nM at D2High. Because the psychotomimetics had higher potency at D2High than at the NMDA site, the psychotomimetic action of these drugs must have a major contribution from D2 agonism. Because these drugs have a combined action on both dopamine receptors and NMDA receptors, these drugs, when given in vivo, test a combined hyperdopamine and hypoglutamate theory of psychosis.

The effect of TGF-beta2 in various vehicles on incisional wound healing

BACKGROUND

The isoforms of transforming growth factor beta (TGF-beta) have been shown to be deficient in models of impaired wound healing. Exogenous application of the growth factor to enhance healing as been investigated. TGF-beta1 has been shown to enhance incisional wound strength, but to be dependent on the vehicle used to carry the cytokine. Because TGF-beta2 has shown safety in human trials of chronic wound healing, this study evaluates TGF-beta2 in acute incisional healing using a variety of vehicles.

METHODS

Using an acute incisional wound model in healthy rats, rhTGF-beta2 was suspended in various vehicles including fibrin sealant (normal commercial concentration), fibrin sealant (dilute concentration), phosphate buffered saline/serum albumin, and a carboxymethycellulose gel. A single dose of the agent was instilled into the incisions at the time of wound closure and breaking strength analyses and histology performed periodically from days 3-14.

RESULTS

TGF-beta2 enhanced the gain of incisional strength in all vehicles during the first two weeks of healing. This was most noticeable by day three with the carboxymethycellulose gel, but by day 7 with the other vehicles. Like reports with TGF-beta1, TGF-beta2 accelerated the gain of wound strength by about three days by day 11. Normal density fibrin sealant delayed incisional healing; whereas, the other vehicles without TGF-beta2 had no significant effect.

CONCLUSIONS

The use of TGF-beta2 appears to be of value in increasing incisional wound strength in the first 14 days post-wounding in healthy rats and this effect is demonstrated in a variety of vehicles. These data support the hypothesis that the "normal" incisional wound healing curve can he shifted to the left. Shortening the time for gain of incisional wound strength may have potential clinical use.

In vivo evidence for dopamine-mediated internalization of D2-receptors after amphetamine: differential findings with [3H]raclopride versus [3H]spiperone

Competition with endogenous dopamine (DA) is usually invoked to explain changes in [(11)C]raclopride binding observed after amphetamine administration in animals and humans. This account has recently been questioned because a number of inconsistencies have been reported that contradict it. In the present study, we investigated whether the decrease in [(3)H]raclopride binding observed in the rat striatum after an amphetamine challenge reflects true competition with endogenous DA or agonist-mediated internalization of D(2)-receptors. We found that the amphetamine-induced decrease in [(3)H]raclopride binding is caused by a decrease in D(2)-receptor density (B(max)) with no change in affinity (K(d)). In contrast, in the same tissue, neither the B(max) nor the K(d) were affected when measured with [(3)H]spiperone. Challenge with amphetamine not only decreased the number of D(2)-receptors but also eliminated the proportion (22%) of receptors usually in the high-affinity state. The addition of Gpp(NH)p had no effect on B(max), suggesting that these receptors were not just noncompetitively bound with dopamine at the cell-surface. Subcellular fractionation studies showed that amphetamine treatment led to a decrease in radioligand binding in the cell-surface fraction for both [(3)H]raclopride and [(3)H]spiperone; however, in the case of [(3)H]spiperone, this was accompanied by a compensatory increase in binding in the intracellular compartment, whereas no increase was seen with [(3)H]raclopride. These data suggest that amphetamine releases dopamine, which binds to the high-affinity state of the D(2)-receptor, leading to its sequestration in some intracellular compartment; in this compartment, sequestered receptors are inaccessible to [(3)H]raclopride binding but can still be bound by [(3)H]spiperone.

Dopamine D2 receptors internalize in their low-affinity state

The present study was done in order to determine whether dopamine internalizes D2 receptors in CHO cells and whether the high-affinity or the low-affinity state of the dopamine D2 receptor is associated with dopamine-induced internalization of dopamine D2 receptors. Using [3H]sulpiride to label D2Long receptors in CHO cells, it was found that dopamine lowered the binding of [3H]sulpiride by 20%. Although the high-affinity states of D2 were converted to low-affinity states by guanine nucleotide, the latter had no effect in blocking the dopamine-induced reduction in [3H]sulpiride binding, indicating that the dopamine-induced internalization of D2 receptors occurred with D2 in the low-affinity state.

Preferential recognition of a fragment species of osteoarthritic synovial fluid fibronectin by antibodies to the alternatively spliced EIIIA segment

OBJECTIVE

To characterize the species of synovial fluid (SF) fibronectin (FN) bearing the alternatively spliced EIIIA segment.

METHODS

SF from patients with osteoarthritis (OA) and rheumatoid arthritis (RA), as well as corresponding affinity isolation products, were subjected to 1-dimensional and 2-dimensional electrophoresis followed by Western blot analysis.

RESULTS

Regardless of the clinical type of arthritis, a polyclonal antibody that recognizes antigenic determinants throughout the FN molecule produced staining of predominantly approximately 200+ and approximately 170-kd species in reduced 1-dimensional electrophoresis. Despite the overall prevalence of the larger species, 4 monoclonal antibodies (mAb) reactive with sequences lying near the center of the EIIIA segment exhibited a relative failure to recognize the larger of these 2 species in OA, but not RA, SF. The absence of recognition of EIIIA sequences within the approximately 200+ kd forms of OA SF FN was unrelated to their derivation from dimers, since anti-EIIIA mAb recognized the smaller fragment species in preference to both monomeric and dimeric forms. The approximately 170-kd EIIIA+ fragments were observed to have minimal gelatin-binding capacity and appeared on 2-dimensional electrophoresis to extend from the N-terminus of FN through at least the center of the EIIIA segment. Similar results were obtained for samples obtained by needle aspiration or arthroscopic lavage, suggesting a widespread applicability of these findings.

CONCLUSION

The approximately 170-kd EIIIA+ species of FN could potentially constitute a soluble "vehicle" by which chondrocyte-regulating EIIIA sequences, liberated from inhibitory flanking C-terminal sequences, could reach cells in the arthritic joint. Additionally, "FN species-specific" recognition of this segment within OA SF could constitute a marker by which to gauge the activity of the OA disease process.

Transforming growth factor beta(2) lowers the incidence of incisional hernias

BACKGROUND

Approximately 200,000 incisional hernias are repaired annually in the United States. The high incidence (11-20%) and recurrence rate (24-54%) for incisional hernias have not changed appreciably in 75 years. Mechanical advances in suture material, incision orientation, and closure technique have failed to eliminate this common surgical complication. A biological approach to acute wound failure may offer a new strategy.

METHODS

A rodent incisional hernia model was used. Seventy rats underwent 5-cm midline celiotomies and were closed with fine, fast-absorbing sutures to induce intentional acute wound failure. Group 1 received no other treatment. The midline fascia in groups 2 and 3 was injected immediately prior to incision with 100 microl of vehicle alone or vehicle containing 1 microg of transforming growth factor beta(2) (TGF-beta(2)). Necropsy was performed on Postoperative Day 28 and the wounds were examined for herniation.

RESULTS

Incisional hernias developed in 88% (35/40) and 79% (11/14) of untreated incisions and those treated with vehicle alone. No hernias formed in the TGF-beta(2)-treated incisions (0/16, P < 0.05). Standard histology and immunohistochemistry demonstrated enhanced macrophage, lymphocyte, and fibroblast chemotaxis and increased collagen I and III production in TGF-beta(2) treated incisions.

CONCLUSIONS

Treatment of abdominal wall fascial incisions with TGF-beta(2) prevented the development of incisional hernias in this rat model. TGF-beta(2) stimulated fascial macrophage and fibroblast chemotaxis as well as acute wound collagen production. A biological approach such as this may reduce the incidence of incisional hernia formation in humans.

Fascial incisions heal faster than skin: a new model of abdominal wall repair

BACKGROUND

Optimal healing of the fascial layer is a necessary component of complete abdominal wall repair. The majority of acute wound healing studies have focused on the dermis. We designed a model of abdominal wall repair that, to our knowledge, for the first time simultaneously characterizes differences in the wound healing trajectories of the fascia and skin.

METHODS

Full-thickness dermal flaps were raised on the ventral abdominal walls of rats, and midline fascial celiotomies were completed. The dimensions of the flap were developed so as to have no detrimental effect on skin healing. The dermal flaps were replaced so that the fascial incisions would heal separately from the overlying skin incisions. Animals were killed 7, 14, and 21 days after operation and fascial and dermal wounds were harvested and tested for breaking strength. Fascial and dermal wounds were also compared histologically for inflammatory response, fibroplasia, and collagen staining.

RESULTS

Fascial wound breaking strength exceeded dermal wound breaking strength at all time points (9.16 +/- 2.17 vs 3.51 +/- 0.49 N at 7 days, P <.05). Fascial wounds also developed greater fibroblast cellularity and greater collagen staining 7 days after the incision. There was no difference in wound inflammatory response.

CONCLUSIONS

Fascial incisions regain breaking strength faster than simultaneous dermal incisions. The mechanism for this appears to involve increased fascial fibroplasia and collagen production after acute injury.

Cytokine manipulation of explanted Dupuytren's affected human palmar fascia

INTRODUCTION

Dupuytren's disease plagues human hands and digits producing fibrotic nodules and fascial cords with resultant debilitating flexion contracture deformities. Interest in this condition is great but because the disease is specific to humans and study has been hampered by the lack of an in vivo model. By utilizing an in vivo "nude" rat model it is possible to maintain and study explanted Dupuytren's contracted palmar fascia for prolonged periods of time.

MATERIALS AND METHODS

Human specimens were divided into four, one for in vitro analysis, and three for model explantation. The explanted tissue was perfused with either transforming growth factor beta-2 (TGFbeta2), its antibody, or a control vehicle. Explant biopsies were obtained at 30 and 60 days and compared to tissue prior to explantation. Immunohistochemistry of collagen I and III, DNA synthesis, protein production, and fibroblast kinetics were serially determined.

RESULTS

Perfusion of explanted Dupuytren's tissue by TGFbeta2 upregulated collagen I and III from biopsies obtained from the explants at 30 days when compared to vehicle control (P < 0.001). Perfusion with antibody prevented this upregulation when compared to vehicle control (P < 0.001). Cell cultures derived from fibroblasts obtained from biopsies of the explants perfused with TGFbeta2 increased DNA synthesis, protein production and fibroblast kinetics.

CONCLUSION

These findings paralleled those from other fibroproliferative disorders suggesting a role for TGFbeta2 in the pathogenesis of Dupuytren's contracture as well as possible novel treatment approaches.

Silicone sheeting decreases fibroblast activity and downregulates TGFbeta2 in hypertrophic scar model

BACKGROUND

Fibroproliferative disorders, which include hypertrophic scars and keloids, represent deviations from the normal process of wound healing. The fibrogenic cytokines have been associated with excessive scarring. It has been proposed that placing silicone in contact with hypertrophic scars may prove to be an effective form of treatment. This may be a result of downregulating fibroblasts and/or decreasing the fibrogenic cytokines. An in vitro model to study wound contraction is a fibroblast populated collagen lattice (FPCL). This study used FPCL as a method to study the effect of silicone sheeting on hypertrophic scar fibroblasts.

METHODS

Fibroblast cultures were obtained and collagen lattices were prepared. Silicone sheeting was placed over the collagen matrix versus Saran wrap used as a treatment control. The amount of gel contraction was measured every 24 hours for five days. The supernatant obtained from the culture medium following completion of the FPCL portion of the experiment was then used in an immunoassay for TGFbeta2.

RESULTS

A statistically significant decrease in amount of FPCL contraction occurred between three of the four brands of silicone sheets used compared to untreated control or Saran wrap treated FPCL. The immunoassay for TGFbeta2 showed a statistically significant decrease with all four types of silicone sheeting.

CONCLUSION

FPCLs populated with burn hypertrophic scar fibroblasts exposed to silicone sheeting have decreased contraction compared to an unexposed control and Saran wrap treated control. In addition, TGFbeta2 is downregulated in the silicone exposed group. It appears that silicone sheeting may act by downregulating fibroblasts and decreasing fibrogenic cytokines.

Overexpression of transforming growth factor beta-2 and its receptor in rhinophyma: an alternative mechanism of pathobiology

Proliferative scarring is one of the clinical features of rhinophyma. The following study was undertaken to test the authors' hypothesis that fibrosis might also play an important role in the pathobiology of rhinophyma. The rhinophyma specimens were obtained from 5 white men (mean age, 67.8 years). Normal skin biopsies near benign facial lesions from 5 additional white men of similar age were obtained to serve as controls. Peroxidase-labeled immunohistochemical staining was performed in the rhinophyma and normal skin specimens for the presence of transforming growth factor (TGF) beta-2 and/or TGF-beta II receptor. Histological slides were then measured for the intensity of staining for TGF-beta2 and TGF-beta II receptor using a computer-aided imaging system. The dermis of the rhinophyma tissue displayed stronger immunoreactivity of TGF-beta2 (p = 0.014) and TGF-beta II receptor (p = 0.006) compared with the normal skin. The results of this study demonstrate the overexpression of the fibrogenic protein TGF-beta 2 and TGF-beta II receptor in rhinophyma tissues. These findings support the authors' hypothesis that fibrosis may also play an important role in the pathobiology of rhinophyma.

In vitro fibroblast populated collagen lattices are not good models of in vivo clinical wound healing

In chronic wounds, the healing process is prolonged and incomplete, proceeding in an uncoordinated manner, and resulting in poor anatomical and functional outcome. There have been numerous attempts to discover models that mimic human wound healing processes. The fibroblast populated collagen lattice is one such model that has been proposed. This study evaluated whether the fibroblast populated collagen lattice can be a model of chronic wound healing using the pressure ulcer as a paradigm. Fibroblast cultures of wound biopsies and wound volume measurements were obtained serially during a four arm blinded, placebo-controlled sequential cytokine clinical trial of pressure ulcers. Fibroblasts obtained from study patients were added to collagen lattices and contraction was determined daily for 10 days. Collagen gel-area measurements were converted to reflect percentage of gel contraction. These data of both edge and base wound biopsies on days 0, 10, and 36 were categorized into treatment groups and one-way analysis of variance showed no significant differences in contraction among these groups. When considering all fibroblast populated collagen lattices, there was significantly greater contraction at days 10 and 36 for cells from both edge and base biopsies compared to day 0 (p < 0.05). The Spearman Rank Correlation test comparing all patients with fibroblast populated collagen lattice results from fibroblasts obtained at the edge or base of the wound at days 0, 10, and 36 and clinical pressure ulcer healing on day 36 showed no correlation. This lack of correlation not only persisted for each of the four treatment arms but also for responder status based on decrease in wound volume over the 35 day trial period. In conclusion, chronic wound healing is a complex process that is not modeled by in vitro fibroblast populated collagen lattices.

Periprosthetic breast capsules contain the fibrogenic cytokines TGF-beta1 and TGF-beta2, suggesting possible new treatment approaches

Periprosthetic breast capsules composed of fibrotic collagenous material with increased collagen production are not dissimilar to other fibrotic conditions occurring in other organs. Fibrosis in the lung, liver, kidney, and skin has been associated with overproduction of the fibrogenic isoforms of transforming growth factor beta (TGF-beta1 and TGF-beta2). If periprosthetic breast capsules contained high levels of these cytokines, possibly new treatment approaches for capsular contraction could be proposed. Breast implant capsules of 35 patients harvested at the time of explantation were examined using indirect immunohistochemistry. Staining intensity for TGF-beta1 and TGF-beta2 was measured in all specimens. Immunohistochemical staining for TGF-beta1 and TGF-beta2 revealed that these two cytokines were present in all capsules analyzed. Minimal TGF-beta1 and TGF-beta2 were found in normal breast tissue. Levels of control vs. TGF-beta1 and control vs. TGF-beta2 were significant (p = 0.004 and p < 0.001 respectively). The presence of TGF-beta isoforms that are known to be fibrogenic may suggest new therapeutic approaches, which are being investigated for other fibrotic conditions.

Sequential cytokine therapy for pressure ulcers: clinical and mechanistic response

OBJECTIVE

To compare the healing response of sequential topically applied cytokines to that of each cytokine alone and to a placebo in pressure ulcers, and to evaluate the molecular and cellular responses.

SUMMARY BACKGROUND DATA

Because of a deficiency of cytokine growth factors in chronic wounds and the reversal of impaired healing in animal models, pressure ulcer trials have been performed with several exogenously applied growth factors. Because single-factor therapy has not been uniformly successful, combination or sequential cytokine therapy has been proposed. Laboratory data have suggested that sequential treatment with granulocyte-macrophage/colony-stimulating factor (GM-CSF)/basic fibroblast growth factor (bFGF) might augment the previously reported effect of bFGF alone.

METHODS

A masked, randomized pressure ulcer trial was performed comparing sequential GM-CSF/bFGF therapy with that of each cytokine alone and with placebo during a 35-day period. The primary measure was wound volume decrease over time. Cytokine wound levels and mRNA levels were serially determined. Fibroblast-populated collagen lattices (FPCLs) were constructed from serial fibroblast biopsies. Cellular ultrastructure was evaluated by electron microscopy. Changes in ease of surgical closure and its relative cost were determined.

RESULTS

Ulcers treated with cytokines had greater closure than those in placebo-treated patients. Patients treated with bFGF alone did the best, followed by the GM-CSF/bFGF group. Patients treated with GM-CSF or bFGF had higher levels of their respective cytokine after treatment. Patients with the greatest amount of healing showed higher levels of platelet-derived growth factor (PDGF) on day 10 and transforming growth factor beta (TGFbeta1) on day 36. Message for the bFGF gene was upregulated after treatment with exogenous bFGF, suggesting autoinduction of the cytokine. FPCLs did not mimic the wound responses. Ultrastructure of wound biopsies showed response to bFGF. Treatment with any of the cytokines improved the wound by allowing easier wound closure. This was most marked for the bFGF-alone treatment, with a cost savings of $9,000 to $9,200.

CONCLUSIONS

Treatment with bFGF resulted in significantly greater healing than the other treatments in this trial. The clinical response appeared to be related to upregulation of the bFGF message and to increased levels of PDGF-AB, bFGF, and TGFbeta1 in the wounds and changes in ultrastructure. The resultant improvements could be correlated with cost savings.

Efficacy of growth factors in the accelerated closure of interstices in explanted meshed human skin grafts

Meshed split-thickness skin grafts, especially when required to be widely spread, do not obtain immediate biologic wound closure. In cases of patients with burns that cover a large percentage of the body surface area, this leaves the patient at risk for metabolic problems and life-threatening infection. Several cytokines and growth factors could theoretically affect the rate of epithelialization and, therefore, the rate of meshed graft interstitial closure. With the use of human meshed skin grafts explanted onto athymic "nude" rats, the epithelialization kinetics of interleukin-4 (IL-4), macrophage colony-stimulating factor (MCSF), keratinocyte growth factor-1 (KGF-1), keratinocyte growth factor-2 (KGF-2), basic fibroblast growth factor (bFGF), and transforming growth factor beta-2 (TGF(B2)) were investigated; the results were compared with the rates of epithelialization of grafts treated with a vehicle control. On postoperative day 3, wounds treated with IL-4, KGF-2, bFGF, and TGF(B2) showed a significantly increased rate of interstitial closure (P < .05). On postoperative days 5 and 7, wounds treated with KGF-2, bFGF, and TGF(B2) all exhibited a significantly higher rate of interstitial closure than the grafts in the control group (P < .05). These data suggest that epithelialization kinetics can be accelerated with the use of several topical growth factors, and they provide support for a future clinical trial.

Exogenous transforming growth factor beta(2) modulates collagen I and collagen III synthesis in proliferative scar xenografts in nude rats

BACKGROUND

Keloid and hypertrophic scars are fibrous dermal tumors characterized by overabundant collagen deposition. Previous studies demonstrated that exogenous transforming growth factor beta (TGF-beta) might increase collagen production in incisional wound models and in vitro. Using an in vivo model of human scar xenografts maintained in congenitally athymic, asplenic "nude" rats, we examined endogenous TGF-beta(2), collagen I, and collagen III levels in keloids and burn hypertrophic scars treated with TGF-beta(2) and TGF-beta(2) antibody.

METHODS

Fresh keloid and burn hypertrophic scar specimens excised from human subjects were explanted to pedicled flaps based on the superficial inferior epigastric vessels in athymic "nude" rats. These flaps were allowed to mature for 3 weeks, after which the scar explants were directly perfused with 200 ng of TGF-beta(2) or 250 microg of TGF-beta(2) antibody daily for 5 consecutive days, then again on Days 10, 15, and 20. Biopsies were taken 30 and 120 days following the initiation of treatment. Immunohistochemical staining was then performed for TGF-beta(2), collagen I, and collagen III. The intensity of staining was quantified.

RESULTS

Our results demonstrated that treatment of human proliferative scars with exogenous TGF-beta(2) results in a significant increase in endogenous TGF-beta(2), collagen I, and collagen III production. By contrast, exogenous addition of anti-TGF-beta(2) antibody significantly decreased endogenous TGF-beta(2), collagen I, and collagen III production.

CONCLUSION

This study supports a causative role for TGF-beta(2) in the formation of proliferative scars and suggests that TGF-beta(2) antibody may be a new potential antiscarring agent.

The effect of denervation on leukocyte function in soft tissue infection

BACKGROUND

The present study was undertaken to investigate the effect of denervation on leukocyte function in soft-tissue infection in an isolated in vivo ovine flap model.

METHODS

Fifteen adult ewes were divided into three groups. An island pedicle flap was raised on the right buttock. In group I (no denervation), the cutaneous nerve remained intact, whereas in group II (acute denervation) the nerve was divided acutely. In group III (prolonged denervation) the nerve was divided 7 days before flap elevation. All flaps received intradermal inoculation of 10(7) Staphylococcus aureus, and the animals were observed for 96 hours.

RESULTS

In both groups II and III, the leukocyte chemiluminescence and chemotaxis were significantly decreased when compared with group I. Furthermore, there was profound impairment of leukocyte functions in group III compared with group II. Group III also had significantly higher bacterial counts, larger septic foci, lower viable leukocyte ratios, and decreased bacterial killing compared with group I.

CONCLUSIONS

Denervation, particularly over a period of time, results in increased bacterial growth of soft-tissue septic foci. This appears to be due to decreased leukocyte function resulting in diminished bacterial killing.

Effects of theophylline, dexamethasone and salbutamol on cytokine gene expression in human peripheral blood CD4+ T-cells

CD4+ T-cells are considered as pivotal in orchestrating the airway inflammation in asthma through the actions of their cytokines. Current hypothesis suggests that the anti-asthma effect of theophylline may be due to its anti-inflammatory actions, although the exact mechanisms remain unclear. The in vitro effect of theophylline on cytokine gene expression in peripheral blood CD4+ T-cells in normal subjects was compared with that of dexamethasone and salbutamol. CD4+ T-cells were cultured with phytohaemagglutin and phorbol myristate acetate in the presence of different concentrations of theophylline (10(-8)-10(-3) M or 0.0018-180 microg x mL(-1)) in one group of subjects (n=8), dexamethasone (10(-9)-10(-6) M or 0.39-390 ng x mL(-1)) in a second group (n=8) and salbutamol (10(-9)-10(-4) M or 0.00058-58 microg x mL(-1)) in a third group (n=8). Gene expression of interleukin (IL)-3, IL-4, IL-5, granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon (IFN)-gamma was semiquantified by reverse transcription-polymerase chain reaction. Suppressed expression of IL-3 (36.9%), IL4 (38.8%), GM-CSF (24.6%) and IFN-gamma (37.7%), but not of IL-5, was only seen with theophylline at a concentration of 10(-3) M (180 microg x mL(-1)) (p<0.05) and not at lower concentrations. In contrast, dexamethasone caused a dose-dependent suppression of transcription of all cytokines, with 39.5% for IL-3, 84.4% for IL-4, 40.6% for IL-5, 50.9% for GM-CSF and 31.8% for IFN-gamma at 10(-6) M (390 ng x mL(-1)) (p<0.05-0.001). Salbutamol did not suppress gene expression of any of the cytokines at the concentrations examined. These data suggest that cytokine gene expression of CD4+ T-cells is not affected at therapeutic concentrations of theophylline and salbutamol, but its suppression is likely to be an important mechanism underlying the therapeutic effect of corticosteroids in asthma.

Effect of TGF-beta2 on proliferative scar fibroblast cell kinetics

Keloids, hypertrophic scars, and burn hypertrophic scars are all forms of proliferative scarring characterized by overabundant matrix formation. Recently these dermal proliferative disorders have been linked clinically to the cytokine transforming growth factor beta (TGF-beta), and in vitro tests have shown it to be responsible for the activation of fibroblasts and their production and deposition of collagen. Using an established in vivo animal model of proliferative scarring, the effects of this cytokine, specifically the isoform TGF-beta2, on these scars were examined. Proliferative scar specimens were implanted into athymic, asplenic nude rats and isolated in sandwich island flaps based on the superficial inferior epigastric pedicle. After establishment of the transferred flap, the scars were injected with varying doses of TGF-beta2 or vehicle for 5 consecutive days and then again on days 10, 15, and 20. The specimens were measured weekly during the period of dosing, and a biopsy was acquired on days 30 and 60. Fibroblasts from the explanted biopsies and the original scars were grown in cell culture, and cell proliferation studies were performed and the results compared. There was a dose response to TGF-beta2, with 200 ng showing the greatest effect. From the original scar specimens, keloid scars demonstrated the greatest cell proliferation kinetics--significantly faster than nonburn and burn hypertrophic scars. After treatment with TGF-beta2, both keloids and burn hypertrophic scars showed an increase in their cell proliferation kinetics compared with vehicle alone. This was not demonstrated with the nonburn hypertrophic scars. Elevated levels of TGF-beta2 are a major contributing factor to the process of proliferative scars, but because nonburn hypertrophic scars do not result in an equally increased response to this cytokine, a truly causative role for this cytokine cannot be promulgated. Rather, it is the combination of the proliferative scar fibroblasts' abnormal response to TGF-beta2 stimulation and elevated levels of this cytokine that controls more accurately the process of keloid and burn hypertrophic scar formation.

The efficacy of 5% Sulfamylon solution for the treatment of contaminated explanted human meshed skin grafts

Large TBSA burns have a deficiency of skin graft donor sites necessitating meshed skin autografts, cultured epithelial autografts or biosynthetic skin substitutes. Because these do not effect immediate complete biological closure of the wound, the burn victim remains at risk for life-threatening infection. Topical antimicrobials can protect colonization of these grafts from becoming invasive sepsis. However, many of these agents are cytotoxic to new partially keratinized epithelial cells. This study using a model of epithelialization kinetics of human meshed skin grafts explanted to athymic 'nude' rats evaluated: (1) the effect of bacterial colonization on the rate of closure of meshed graft interstices; (2) the efficacy of 5% Sulfamylon solution for bacterial control and (3) the effect on interstitial closure rates caused by control of bacterial proliferation. Results showed the rate of interstitial closure was progressive over 7 days in noncontaminated grafts treated with moistened saline dressings. Areas of total closure of a 1:1.5 meshed graft were seen as early as 5 days. When grafts were inoculated with 10(2) or 10(3) Pseudomonas aeruginosa organisms and treated with saline moistened dressings, the resultant bacterial load rose to 10(6) organisms, less than 3% of the interstices closed and grafts were destroyed. With the same organism level of contamination, bacterial levels were eradicated with topical 5% Sulfamylon solution, interstitial closure rates returned to normal and areas of total meshed graft closure were seen by day 4. These data demonstrate the efficacy of 5% Sulfamylon solution on epithelialization kinetics of contaminated meshed skin grafts.

In vivo characterization of keratinocyte growth factor-2 as a potential wound healing agent

Human keratinocyte growth factor-2 exerts a proliferative effect on epithelial cells and mediates keratinocyte migration. It has also been shown to increase both deposition of granulation tissue and collagen and maturation of collagen. Because these properties should affect the healing trajectory of wounds, this study set out to investigate the effects of keratinocyte growth factor-2 on the healing of three different types of wounds. Human meshed skin grafts explanted to athymic "nude" rats, surgical incisions in Sprague-Dawley rats, and acute excisional rat wounds inoculated with Escherichia coli were used. Two concentrations of recombinant human keratinocyte growth factor-2 were compared to a vehicle control and keratinocyte growth factor-1. Keratinocyte growth factor-2 significantly accelerated the rate of epithelialization in the meshed skin graft model and effected a modestly more rapid gain in breaking strength of surgical incisions than keratinocyte growth factor-1 or the vehicle control treatment. Neither keratinocyte growth factors accelerated wound closure by contraction of the excisional wounds. Based on these data, keratinocyte growth factor-2 may be useful in accelerating healing in wounds healing mainly by the process of epithelialization such as venous stasis ulcers, partial thickness burn wounds, and skin graft donor sites. It might also accelerate the gain in incisional wound strength in acute surgical or traumatic wounds.

TGF-beta2 activates proliferative scar fibroblasts

BACKGROUND

Cytokines, such as the transforming growth factor beta (TGF-beta) isoforms, have been linked to the formation of proliferative scars. This study examines the stimulating effects of exogenous TGF-beta2 on cultured keloid, burn hypertrophic scar, and normal skin fibroblasts and whether such effects can be suppressed with TGF-beta2 antibody.

METHODS

In vitro, the fibroblast-populated collagen lattice (FPCL) is used in the evaluation of fibroblast activation by measuring contraction of the lattice over time. Primary cultures of fibroblasts were grown from keloids, burn hypertrophic scars, and normal skin using standard cell culture techniques. TGF-beta2 (10 ng/ml) was added to each of the three types of cell cultures and placed on prefabricated FPCLs. Each was tested against their normal control counterparts. TGF-beta2 antibody (100 ng/ml) was then placed on the TGF-beta2-treated FPCLs. All lattices were allowed to contract and areas were measured for 5 days.

RESULTS

Compared to controls, keloid fibroblasts were most affected by the addition of exogenous TGF-beta2. Normal skin fibroblasts did not show a significant increase in contraction early on, yet a significant difference was seen as time progressed. The addition of TGF-beta2 antibody inhibited the function of keloid and burn hypertrophic scar fibroblasts. It also reversed the increased contraction of the TFG-beta2-treated proliferative scar fibroblasts.

CONCLUSION

By utilizing an in vitro model, we have demonstrated that TGF-beta2 antibody reverses the increased contraction of FPCLs by proliferative scar fibroblasts treated with TGF-beta2. This points to a possible treatment modality in patients afflicted with this disfiguring problem.

Evaluation of the efficacy of a hospital-based asthma education programme in patients of low socioeconomic status in Hong Kong

BACKGROUND

Good asthma control requires optimal medical treatment in conjunction with appropriate self-management. In the West, the effectiveness of patient education on improving self-management has been well documented. However, data amongst Asian populations are lacking. We performed a pilot study to evaluate the efficacy of a hospital based education programme aimed at improving self-management skills and reducing morbidity in a Chinese population with low socioeconomic status and education level.

METHODS

Our asthma education programme was a low-cost programme conducted in essence by specialist respiratory nurses. Patients attending our asthma clinic were instructed during a two-hour educational session on the pathophysiology of asthma, its potential triggers, the appropriate use of medications including proper inhaler techniques, and the self-management of their disease. These instructions were reinforced by video sessions at subsequent outpatient clinic attendance when patients' inhaler and peak flow techniques were checked by the same nurses and their self-management plan re-examined by the attending physicians. Asthma knowledge, inhaler technique, FEV1 and peak expiratory flow (PEF), and patients' self-rating of their asthma were determined at baseline, 6 months and 1 year after the intervention. Morbidity was assessed by the numbers of hospitalizations, unscheduled visits to family physicians and accident and emergency department attendance, courses of oral steroid used and days off work or school at baseline and 1 year.

RESULTS

Two hundred and thirty patients were recruited for the study, 83% completing the entire assessment period. The group demonstrated significant improvements in lung function: the mean FEV1 +/- SD increased from 63.6 +/- 20.6% of predicted values at baseline to 68.5 +/- 22.3% at 6 months and 68.6 +/- 22.8% at 1 year (P < 0.05), and the mean PEF +/- SD increased from 64.6 +/- 23.0% of predicted values at baseline to 75.4 +/- 27.0% at 6 months and 76.8 +/- 24.5% at 1 year(P < 0.001). There were also significant improvements in inhaler technique (P < 0.01), asthma knowledge (P < 0.001), patients' self-rating of their asthma (P < 0.05), and reductions in the numbers of hospitalizations (P < 0.01), visits to family physicians (P < 0.001) and accident and emergency department attendance (P < 0.001) during the study period. Patients with moderate to severe asthma as defined by an FEV1 of < 80% of predicted values were most likely to benefit from the programme.

CONCLUSIONS

We conclude that patient education is likely to be an essential component in the holistic approach to the management of asthma even amongst Asian populations of low socioeconomic status and education level. Further studies using randomised controlled trials are necessary to consolidate our findings.

Toxic effects of capsaicin on keratinocytes and fibroblasts

Pain management for partial-thickness burns and split-thickness skin graft donor sites remains a persistent problem. Topical capsaicin (trans-b-methyl-N-vanillyl-noneamide) has been successful for pain relief in postherpetic neuralgia, arthritis, and diabetic neuropathy. It is thought to work by inhibiting type C cutaneous factors and by releasing substance P, which is essential for wound healing. To evaluate the effects of topical capsaicin treatment on burn wounds and donor sites, an in vitro study was designed to consider cytotoxic effects of commercial concentrations of capsaicin on keratinocytes and fibroblasts. Human keratinocytes and human fibroblasts were grown in tissue culture and exposed to varying concentrations of capsaicin (0.025% weight/volume to 0.2% weight/volume). In addition, fibroblast-seeded collagen matrixes were exposed to capsaicin to evaluate the compound's ability to cause cytotoxic effects beneath the surface. Keratinocyte growth was reduced 21% to 31% in commercial concentrations of capsaicin 0.025% to 0.20% weight/volume. Fibroblasts were reduced 5% to 10% during the first 6 hours of exposure to capsaicin and 30% after 24 hours across the full range of concentrations tested. At concentrations of at least 0.1% weight/volume, capsaicin penetrated the collagen matrixes, resulting in fibroblast degeneration not only on the surface but also in the inner layers. On the basis of the fact that capsaicin was demonstrated to be cytotoxic to keratinocytes and fibroblasts and on the basis of its known detrimental effect on wound healing, it does not appear that topical capsaicin is indicated for the treatment of burns.

Differential production of apoptosis-modulating proteins in patients with hypertrophic burn scar

BACKGROUND

The biochemical and cellular pathways resulting in the production of proliferative scar in the thermally injured patient remain incompletely elucidated. A promising area of investigation is the phenomenon of programmed cell death and its modulation. The following study was designed to quantify differential levels of the bcl-2 protooncogene and the Fas cell surface receptor, two apoptosis-modulating proteins, in the peripheral blood mononuclear cell (PBMC) fractions of burn patients with hypertrophic scar versus those considered to have healed normally. The study also encompassed an immunohistochemical examination of fibroblasts in vitro, to identify differential levels of Fas, bcl-2, and interleukin converting enzyme (ICE).

METHODS

PBMC fractions were isolated from two matched burn patient cohorts of 10 patients each, the experimental group carrying the clinical and histopathologic diagnosis of hypertrophic burn scar. The supernatant from each mitogenically stimulated specimen was halved and subjected to the Fas/APO-1 enzyme-linked immunosorbent assay (ELISA) and the bcl-2 ELISA. Results for each assay were compared between groups by unpaired t tests. Further biopsy specimens of isolated proliferative scar were used in vitro to analyze the role of these apoptosis-modulating proteins and ICE. This immunoperoxidase technique was analyzed qualitatively.

RESULTS

The expression of the bcl-2 protein in the PBMC fractions of the burn patients with hypertrophic scar is significantly elevated in comparison to the control cohort (307.72 +/- 72.29 u/ml vs 31.55 +/- 6.73 u/ml; P = 0.0042). The quantitative levels of the Fas receptor did not differ significantly between the groups, respectively (0.3988 +/- 0.179 u/ml vs 0.2899 +/- 0.066 u/ml; P = 0.5787). Immunoperoxidase staining of proliferative scar fibroblasts and those from surrounding skin revealed relatively decreased levels of membrane-bound Fas and ICE. bcl-2 was not detectable in these specimens.

CONCLUSIONS

Differential expression of the bcl-2 protooncogene and the Fas cell surface receptor in the PBMC fraction of patients with burn injuries may suggest a disequilibrium in a complex biochemical signaling mechanism mediating programmed cell death. The increased levels of bcl-2 could be responsible for delayed fibroblast apoptosis, resulting in the disruption of normal healing and subsequent hypertrophic scarring. This is confirmed by an in vitro examination of wound fibroblasts versus those from surrounding uninjured skin. This immunoperoxidase technique reveals a localized relative decrease in Fas and ICE, two apoptosis-inducing proteins, at the level of the fibroblast in the proliferative scar specimen.

An in vivo model of human proliferative scar

BACKGROUND

Many aspects related to the biology and the effective therapy of proliferative scars have remained undefined, in part due to a lack of an accurate and reproducible animal model with which to systematically study them. This report describes a new model for investigating the pathophysiology and manipulation of human proliferative scars.

MATERIALS AND METHODS

Human proliferative scars (n = 86) were explanted into flaps based on isolated vascular pedicles in congenitally athymic rats. Serial analysis of the structural and functional integrity of the explanted scars was performed by microscopy and by measurement of human procollagen type III peptide (PIIIP) production, human factor VIII immunostaining, and in vitro cellular proliferation.

RESULTS

By these methods, both fibroblastic and epithelial components of explanted scar specimens retained the histologic characteristics of original human scar specimens, for up to 12 months. Over the same duration, scar explants continued to have high levels of human PIIIP, comparable to those found in original surgical specimens. The microvasculature of scar explants demonstrated a double basement membrane, with no staining of human factor VIII in the inner capillary endothelial layer, suggesting that host vessels were growing into ghost vessels of the human donor scar. Human factor VIII staining decreased over time. Fibroblasts cultured from explanted scar demonstrated less aggressive growth characteristics than those from original surgical specimens.

CONCLUSIONS

This new model is the first to allow such long-term maintenance and serial evaluation of human proliferative scar on an accessible, isolated vasculature. It may prove useful in further defining the biology and therapy of this widespread pathologic process.

Beneficial effect of Aloe on wound healing in an excisional wound model

Recent evidence from in vitro and in vivo experiments suggests that topical antimicrobials may be toxic to fibroblasts and keratinocytes and retard wound healing. The purpose of this study was to determine the effects of Aloe, a potential wound-healing agent, on wound contraction in excisional wounds treated with topical antimicrobials. Sprague-Dawley rats were prepared with four 1.5 cm2 dorsal defects through the skin and panniculus. The animals were divided into five groups (n = 10 per group): (1) Aloe, (2) NaOCl solution (0.025%), (3) mafenide acetate, (4) mafenide acetate + Aloe, and (5) control. Wounds were treated topically for 14 days 3 times a day. Serial standard photographs and serial wound planimetry were performed weekly. Following healing, the breaking strength of each resultant scar was determined using an Instron tensiometer. Kruskal-Wallis, ANOVA, and multiple comparison methods were used for data analysis. Aloe and NaOCl solution significantly accelerated wound contraction (p < 0.05). In the mafenide acetate + Aloe group, contraction was similar to the control, whereas the mafenide acetate alone retarded wound healing. The addition of Aloe in combination and alone in wounds increased the breaking energy when compared to controls (p < 0.05). Aloe appears to expedite wound contraction and neutralize the wound retardant effect seen with the topical mafenide acetate alone. This effect appears to be due to an increased collagen activity, which is enhanced by a lectin, consequently improving the collagen matrix and enhancing the breaking strength.

The 1997 Moyer Award. Cytokine production in patients with hypertrophic burn scars

To clarify the significance of the role of the immune system in the formation of proliferative burn scars, this study attempted to identify differential production of cytokines between patients with burn injuries with and without hypertrophic scars. Mononuclear cell fractions were isolated from the peripheral blood (PBMC) of each patient and incubated with and without antigenic or mitogenic stimulation. The resultant supernatants were then assayed by ELISA techniques for production of various cytokines. The production of IL-1, IL-6, TNF-alpha, and TGF-beta2 by unstimulated PBMC was elevated significantly in patients with proliferative scar compared to control patients. Production of TGF-beta2 by stimulated PBMC also was elevated significantly in patients with proliferative scar. This study suggests that an increase in the production of TGF-beta and of proinflammatory cytokines by mononuclear cells may play a significant role in the processes that lead to excessive scar formation after burn injury.

Minoxidil and wound contraction

Minoxidil has been proposed as a potential topical inhibitor of wound contraction and proliferative scarring. Suggestions for this application are derived from in vitro investigations demonstrating inhibition of various fibroblastic functions. The purpose of this study was to attempt to establish in vivo support of these effects using an established animal model of wound contraction. Standardized cutaneous wounds were created on the dorsum of Sprague-Dawley rats, which were divided equally into six treatment groups. Wounds were treated daily after tracing their unhealed areas. On complete closure of the wounds, analyses of the contraction rates and tensile strength were performed for comparison among groups. Minoxidil did not demonstrate significant inhibition of wound contraction rates relative to either an inert vehicle, an active vehicle, or no treatment. Contrarily, as previously demonstrated in this animal model, silver sulfadiazine did demonstrate significant inhibition of wound contraction rates relative to both vehicles. No significant difference in tensile strength was demonstrated among groups. These observations do not support the proposed use of minoxidil as an "antifibrotic" agent.

In vivo characterization of interleukin-4 as a potential wound healing agent

Interleukin-4 increases the synthesis of extracellular matrix proteins, including types I and III collagen and fibronectin, by both human and rat fibroblasts. Because fibroblasts are the final common effector cells of most phases of tissue repair, this study set out to investigate the effects of interleukin-4 on the healing of three different types of wounds. Acute excisional and chronic granulating wounds inoculated with Escherichia coli and incisional wounds in streptozotocin-induced diabetic Sprague-Dawley rats were used. Recombinant murine or human interleukin-4 was applied topically to the open wounds at doses of 0.1, 1.0, or 10.0 microg/cm(2)/wound for 5 or 10 days. Incisional wounds received the same doses once-at the time of wounding. The time taken to achieve wound closure or wound breaking strength measurements of wounds was recorded and compared with relevant untreated control groups. Wound contraction was impaired in the presence of bacteria, and this was reversed by all doses of recombinant murine interleukin-4. Recombinant murine interleukin-4 had no effect on the wound closure of noncontaminated wounds; it reduced wound breaking strength in acute excisional wounds, except in a contaminated setting when wounds were treated with 1.0 pg/cm(2)/wound. Recombinant interleukin-4 (1.0 microg) improved breaking strength of both diabetic and normal incisional wounds. The apparent pleiotropic effect of interleukin-4 on wound breaking strength under different wound conditions may be related not only to the activity of the fibroblast but also the ratio of cross-linked collagen/total collagen content of wounds. This study suggests that interleukin-4 may be a useful agent for accelerating closure of wounds, particularly where healing is impaired.

Determination of endogenous cytokines in chronic wounds

OBJECTIVE

This study objectively characterized the microenvironment of indolent, chronic wounds by developing a method by which minute quantities of cytokines could be extracted from chronic wounds and separately identified.

SUMMARY BACKGROUND DATA

Recombinant DNA technology and the ability to clone compounds such as cytokines allow new management schemes for the treatment of acute and chronic wounds. Before treatment with an exogenous cytokine is started, it would be helpful to know the endogenous level of that cytokine in the wound. Although various methods of extracting cytokines from acute wounds have been reported, no techniques have existed to reliably measure endogenous levels of cytokines in chronic wounds.

METHODS

Porous, inert hydrophilic dextranomer beads were tested for their ability to absorb or adsorb protein and cytokines in vitro with either albumin or albumin laced with various known amounts of cytokines, and then from chronic human pressure ulcers. The Bradford protein assay was used to determine protein levels. Enzyme-linked immunosorbent assay (ELISA) techniques were used to determine levels of platelet-derived growth factor (PDGF)-AB, basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and transforming growth factor-Beta (TGF-beta) extracted by the beads.

RESULTS

Between 88% and 98% of known amounts of albumin could be recovered. Similarly, more than 90% of the laced cytokines could be recovered. In 20 grade III/IV pressure ulcers, although protein concentrations were remarkably similar, endogenous levels of cytokine growth factors varied tremendously. Platelet-derived growth factor-AB ranged from 49 to 867 pg/mL; bFGF from 47 to 697 pg/mL; and EGF from nondetectable to 247.5 pg/mL. TGF-B was not detected in 17 of the 20 pressure ulcers.

CONCLUSIONS

This new technique appears useful for measuring endogenous levels of cytokines. Levels of cytokines found in these chronic wounds are much lower than those reported from acute wounds. The marked variation found among the 20 wounds may help to explain the differences reported in recent wound healing trials with exogenous cytokines.

Effects of granulocyte-macrophage colony-stimulating factor on wound contraction

The effect of topical recombinant murine and human GM-CSF, 1 or 10 micrograms/cm2 for one to ten days, on the contraction and healing of acute and chronic granulating wounds infected with Escherichia coli was studied in Sprague-Dawley rats. Bacterial contamination of wounds produced significant inhibition of wound contraction. Application of GM-CSF at either dose level to infected wounds markedly increased the rate of wound closure compared to the rate in infected untreated controls. Ten days treatment was found to be more effective than a single application. An advanced stage of wound healing was observed at ten days in the GM-CSF-treated rats compared with controls. Bacterial counts decreased in the GM-CSF-treated wounds which may suggest bactericidal activity. Topical treatment with GM-CSF was shown to effectively inhibit the retardation of wound closure produced by bacterial contamination and may therefore be useful in the management of patients with infected wounds.

Application of basic fibroblast growth factor may reverse diabetic wound healing impairment

This study examines the effect of application of basic fibroblast growth factor (bFGF) on the wound healing impairment seen in streptozotocin-induced diabetic (SD) rats compared with control nondiabetic (NL) animals. Under general anesthesia, a 6-cm dorsal incision was made through the skin and panniculus carnosus. Both the NL and SD wounds were injected with 0.1 ml of one of the following three solutions: saline, vehicle, and 10 micrograms of bFGF. The wounds were closed with interrupted sutures of 4-0 nylon. The animals were returned to their cages and sacrificed at 7, 10, 14, or 21 days later. Breaking strength of the wound was analyzed by using an Instron Tensiometer 4201 to assay for relative collagen maturation. Data among groups were compared using an analysis of variance. At 7 and 10 days, all NL wounds were stronger than all SD wounds. By 14 days there was no statistically significant difference in breaking strength between the bFGF-SD wounds and all subgroups of NL wounds. The bFGF-SD subgroup was statistically significantly stronger than the saline-SD (p < 0.02) and vehicle-SD (p < 0.01) wounds. At 21 days the bFGF-SD wounds were statistically significantly stronger than the vehicle-SD wounds to a confidence level of p < 0.001. These findings indicate that application of bFGF may reverse the impairment seen in diabetic wound healing.

Evidence for Kupffer cell activation by burn injury and Pseudomonas exotoxin A

Postburn metabolic and immunological alterations may in part be due to translocation of gut exotoxin and endotoxin, which can result in tumour necrosis factor (TNF) and prostaglandin E (PGE) production by macrophages. We evaluated the effect of burn injury, plus exotoxin and endotoxin on TNF-alpha and PGE production by Kupffer cells, and peritoneal macrophages. Adult Wistar rats underwent 30 per cent TBSA burn or sham burn. Kupffer cells were harvested from rat livers and peritoneal macrophages from the abdominal cavity 24 h postburn. They were cultured overnight at 1 x 10(6) cells/ml and stimulated with saline, 5 micrograms/ml of Pseud. aeruginosa Exotoxin A (Exo-A), 5 micrograms/ml of Pseud. aeruginosa Endotoxin (Endo), Exo-A + Endo, or Exo-A + Endo + the PGE derivative 16,16 dimethyl-PGE (dPGE) (10 micrograms/ml). The supernatants were harvested after 4, 24 and 48 h of culture and assayed for TNF-alpha and PGE. Results showed that burn injury induced an increase in TNF-alpha and PGE production by Kupffer cells stimulated with Exo-A, Endo, and both Exo-A + Endo (P < 0.05). The release of TNF-alpha by Kupffer cells was downregulated by exogenous PGE (P < 0.05). The increased TNF-alpha production was inversely related to PGE levels. In conclusion, both burn injury and Exo-A potentiate the responsiveness of Kupffer cells and peritoneal macrophages to endotoxin as measured by the rate of production of TNF-alpha and PGE. PGE may locally downregulate the immune response by limiting Kupffer cells' and peritoneal macrophages' TNF-alpha production.

Pseudomonas aeruginosa exotoxin A: its role in retardation of wound healing: the 1992 Lindberg Award

Bacterial concentrations greater than 10(5) colony-forming units/gm of tissue prevent wound healing. However, it has not been determined whether it is the number of bacteria or a toxin produced by these organisms that impedes the wound healing process. Pseudomonas aeruginosa (PSAR), a burn wound pathogen, produces a dermonecrotic toxin, exotoxin A. Studies have indicated a role for exotoxin A in the pathogenicity of PSAR. We investigated the role of exotoxin A in the retardation of contraction. Acute granulating wounds were created on 90 Sprague-Dawley rats. The animals were equally divided into six groups and were treated topically as follows: group 1, sham: no infection, no treatment; group 2, exotoxin A; group 3, exotoxin A and antiexotoxin; group 4, autoclaved PSAR 10(6); group 5, 10(6) viable PSAR inoculated in the wound; group 6, 10(6) viable PSAR and antiexotoxin. Wound contraction was measured with the use of planimetry twice a week. Serial biopsies were performed on all wounds. Contraction rates revealed significantly (p < 0.05) retarded closure in the animals treated with exotoxin A and in the viable PSAR group when compared with the rates of the noninfected control groups. Animals treated with exotoxin A plus antiexotoxin A and those treated with live PSAR and antiexotoxin showed contraction rates identical to the control groups. These data suggest that exotoxin A in PSAR infections retards wound healing and that neutralization of the toxin restores the normal healing process.

The protection against and treatment of a liquid propane freeze injury: an experimental model

Liquid propane causes a severe, deep thermal injury in unprotected tissue. Delayed surgical intervention, as for thermal burns, has been the gold standard of treatment. An animal model of liquid-propane injury was devised to document injury, to demonstrate a better method of protection, and to define an appropriate management protocol. Twenty-eight rats were classified into four groups: unprotected tissue (n = 8), skin covered with wool (n = 8), skin covered with Neoprene (Wm. H. Horn & Brothers Inc., Philadelphia, Pa.) (n = 8), and skin covered with wool plus Neoprene (n = 4). Each group was subdivided into two exposure times: 6 seconds and 30 seconds. The mean temperatures +/- standard error of the mean of the various tissue levels initially and at 6 and 30 seconds of exposure were determined. Histologic examination demonstrated that full-thickness tissue necrosis occurred in unprotected and wool-covered tissue. Areas that were covered with Neoprene showed intact skin and subcutaneous tissue with underlying muscle necrosis. Examination of the tissue that was covered with wool plus Neoprene showed no histologic damage. There was no sign of tissue regeneration at the wound periphery, and there was no histologic difference in any group, whether the examination took place at 1 or 5 days after injury. This study demonstrated that the best form of protection appears to be a wool glove liner covered with a Neoprene glove. The histologic evidence suggests that a liquid-propane injury to unprotected tissue should be managed aggressively with early excision and grafting.

Transient and resident microflora of burn unit personnel and its influence on burn wound sepsis

The exogenous contamination of a thermally injured patient by contact with the health are team has been a major concern of all burn units. Since the University of Chicago Burn Center routinely monitors each burn injury for sepsis by quantitative bacteriology and recently examined the microbial population present on the hands of the health care team, it was felt that these combined data would shed some pertinent information on exogenous burn wound sepsis. Twenty-nine patients with clinical burn wound sepsis and a bacterial level of greater than 10(5) bacteria/gram of tissue were studied. These patients yielded a variety of microorganisms with P. aeruginosa and Staphylococcus aureus being predominant, followed in incidence by Candida albicans. The resident and transient microflora isolated from each member of the health care team treating the specific individual concerned did not correlate with the causative agent of burn wound sepsis. The most frequent isolate from the staff personnel was Staphylococcus epidermidis followed by Micrococcus species. Though colonization of the thermally injured individual has been reported, these data strongly suggest that colonization is primarily one of an endogenous source rather than that of an exogenous one.

Polymyositis, prednisone, and pheomycotic cyst

An immunosuppressed patient with polymyositis presented with an apparent ganglion of the left foot. During the operative procedure, a cystic mass inconsistent with a ganglion was excised and immediately sent to the Quantitative Bacteriology Laboratory. A rapid slide examination revealed yeastlike bodies present in the tissue. The remainder of the tissue was sent to pathology for special staining. The H&E and GMS stains revealed findings compatible with the diagnosis of a pheomycotic cyst, and the appropriate cultures confirmed this. This represents an unusual opportunistic infection in an immunosuppressed host. As more patients are managed with immunosuppressive drugs, this diagnosis will need to be considered much more frequently if treatment is to be effective.

Comparison of silver sulfadiazine, povidone-iodine and physiologic saline in the treatment of chronic pressure ulcers

The presence of bacteria and local infection is an important factor in the local management of chronic pressure ulcers. For successful closure of the ulcer, the bacterial count should be 10(5) or less per gram of tissue in the granulating wound. In a prospective randomized study of 45 (eventually 40) hospitalized patients, silver sulfadiazine (Silvadene) cream and povidone-iodine (Betadine) solution were compared to physiologic saline for effectiveness in preparing pressure ulcers for closure. Quantitative bacteriologic techniques on tissue biopsy specimens were used for objective evaluation. In 100 percent of the ulcers treated with silver sulfadiazine cream (15 patients) the bacterial counts were reduced to 10(5) or less per gram of tissue within the three-week test period, compared to 78.6 percent in those treated with saline (14 patients) and 63.6 percent in those treated with povidone-iodine solution (11 patients). Moreover, the ulcers treated with silver sulfadiazine cream responded more rapidly, with one-third showing bacterial levels of less than 10(5) within three days, and half within a week.