[Current status of laser therapy of hemangioma in infants. Case reports and review of the literature]

Today the management of hemangiomas is still a great challenge for physicians, even for the most experienced of clinicians. With the introduction of lasers, new ways of treating hemangiomas have been found. Four case reports document the importance of early treatment. In addition, the differentiated use of various laser systems and their effects, limitations, and side effects are shown and discussed.

Discoupling the Ca(2+)-activation from the pore-forming function of the bi-component Panton-Valentine leucocidin in human PMNs

The consecutive cell activation, including Ca(2+)-channel opening, and pore formation leading to human neutrophil lysis were the two functions of the staphylococcal Panton-Valentine leucocidin attempted to be discoupled by site-directed mutagenesis. In a first approach consisting in deletions of the cytoplasmic extremity of the transmembranous domain, we produced a LukF-PV DeltaSer125-Leu128 with a slightly reduced Ca(2+) induction but with a significantly lowered lytic activity when combined with its synergistic protein LukS-PV. The second approach consisted in the modification of charges and/or introduction of a steric hindrance inside the pore, which also led to interesting mutated proteins: LukF-PV G131D, G131W and G130D. The latter had an intact Ca(2+) induction ability while the lytic one was 20-fold diminished. Binding properties and intrinsic pore diameters of these discoupled toxins remained comparable to the wild-type protein. The mutated proteins promoted interleukin-8 secretion, but they were rather inactive in an experimental model. New insights are brought concerning the role of the two functions in the virulence of this bi-component leucotoxin.

Growth factor-regulated expression of enzymes involved in nucleotide biosynthesis: a novel mechanism of growth factor action

Keratinocyte growth factor (KGF) is a potent and specific mitogen for epithelial cells, including the keratinocytes of the skin. We investigated the mechanisms of action of KGF by searching for genes which are regulated by this growth factor in cultured human keratinocytes. Using the differential display RT-PCR technology we identified the gene encoding adenylosuccinate lyase [EC 4.3.2.2] as a novel KGF-regulated gene. Adenylosuccinate lyase plays an important role in purine de novo synthesis. To gain further insight into the potential role of nucleotide biosynthesis in the mitogenic effect of KGF, we cloned cDNA fragments of the key regulatory enzymes involved in purine and pyrimidine metabolism (adenylosuccinate synthetase [EC 6.3.4.4], phosphoribosyl pyrophosphate synthetase [EC 2.7.6.1], amidophosphoribosyl transferase [EC 2.4.2.14], hypoxanthine guanine phosphoribosyl transferase [EC 2.4.2.8] and the multifunctional protein CAD which includes the enzymatic activities of carbamoyl-phosphate synthetase II [EC 6.3.5.59], aspartate transcarbamylase [EC 2.1.3.2] and dihydroorotase [EC 3.5.2.3]). Expression of all of these enzymes was upregulated after treatment with KGF and also with epidermal growth factor (EGF), indicating that these mitogens stimulate nucleotide production by induction of these enzymes. To determine a possible in vivo correlation between the expression of KGF, EGF and the enzymes mentioned above, we analysed the expression of the enzymes during cutaneous wound repair, where high levels of these mitogens are present. Indeed, we found a strong mRNA expression of all of these enzymes in the EGF- and KGF-responsive keratinocytes of the hyperproliferative epithelium at the wound edge, indicating that their expression might also be regulated by growth factors during wound healing.

Overexpression of activin A in the skin of transgenic mice reveals new activities of activin in epidermal morphogenesis, dermal fibrosis and wound repair

Recently we demonstrated a strong induction of activin expression after skin injury, suggesting a function of this transforming growth factor-beta family member in wound repair. To test this possibility, we generated transgenic mice that overexpress the activin betaA chain in the epidermis under the control of a keratin 14 promoter. The transgenic mice were significantly smaller than control littermates, and they had smaller ears and shorter tails. In their skin, the fatty tissue was replaced by connective tissue and a severe thickening of the epidermis was found. The spinous cell layer was significantly increased, and the epidermal architecture was highly disorganized. These histological abnormalities seem to result from increased proliferation of the basal keratinocytes and abnormalities in the program of keratinocyte differentiation. After skin injury, a significant enhancement of granulation tissue formation was detected in the activin-overexpressing mice, possibly as a result of premature induction of fibronectin and tenascin-C expression. These data reveal novel activities of activin in the regulation of keratinocyte proliferation and differentiation as well as in dermal fibrosis and cutaneous wound repair.

Soluble Rous sarcoma virus reverse transcriptases alpha, alphabeta, and beta purified from insect cells are processive DNA polymerases that lack an RNase H 3' --> 5' directed processing activity

Reverse transcriptase (RT) isolated from Rous sarcoma virus (RSV) consists of heterodimeric RTalphabeta, RTalpha, and RTbeta. The alpha subunit (63 kDa) contains an N-terminal polymerase and a C-terminal RNase H domain. The N terminus of beta (95 kDa) corresponds to alpha with the integrase domain attached to the C terminus (32 kDa). We have constructed baculoviruses expressing the genes for alpha or beta or the entire pol (99 kDa). Infection of insect cells with recombinant virus yielded highly active and soluble RSV RT enzymes that could be purified to >90% homogeneity. HPLC gel filtration showed that alpha is a dimeric enzyme that can be partially monomerized upon the addition of 45% Me(2)SO. DNA synthesis on DNA-DNA and DNA-RNA primer-templates in the presence of competitor substrates revealed that alphabeta and beta as well as alpha are processive polymerases. However, the affinity of beta and alphabeta for primer-template substrates appears to be higher than that of alpha. All RSV enzymes investigated have the potential to displace RNA-RNA duplexes more efficiently than human immunodeficiency virus type 1 RT. Unlike human immunodeficiency virus type 1 RT, RSV RTs can catalyze an initial RNase H endonucleolytic cleavage of the RNA template but not a 3' --> 5' directed processing activity.

Treatment of venous malformations with an intense pulsed light source (IPLS) technology: A retrospective study

BACKGROUND AND OBJECTIVE

The intense pulsed light source (IPLS) technology provides an innovative concept in the treatment of vascular lesions. We investigated the effectiveness of IPLS in the treatment of venous malformations.

STUDY DESIGN/MATERIALS AND METHODS

A retrospective study of 11 patients with venous malformations (VMA) treated with IPLS was initiated. Clinical VMA characteristics recorded were size and location. Data collected included treatment parameters (filters, pulse duration, fluence, and pulse sequencing), % clearance, and side effects (e.g., swelling, blisters, crusting, pain, altered pigmentation, and scarring).

RESULTS

Good and very good (70-100%) clearance was achieved in 8 malformations smaller than 100 cm(2). Especially small lesions needed only 2-3 treatments. Three VMA larger than 100 cm(2) could be cleared well in an average of 18 sessions. The most frequently used parameters were the 590 nm filter in long pulse mode, triple pulses, and fluences at an average of 80.4 J/cm(2). Side effects included prolonged erythema in 23.6, swelling in 17.9%, crusting in 4.7%. Bleeding, hypo-, hyperpigmentation, and scarring were rare (0.9% respectively).

CONCLUSION

IPLS presents an effective method for treating VMA, especially small malformations, with a justifiable rate of side effects when optimal parameters are chosen.

Paradoxical role of PGE2 and cAMP in Actinobacillus actinomycetemcomitants strain Y4-induced lymphocyte proliferation

An immune mechanism has been suggested in the pathogenesis of periodontal disease. Actinobacillus actinomycetemcomitants (Aa) has been implicated as one of the etiological agents that induces the major immune response together with a dense infiltrate of inflammatory cells. But the exact role of these immune cells in periodontal disease has not yet been clarified. In this study the T lymphocyte (TL) proliferative response was evaluated after having being exposed to free cell supernatant (SN) from Aa. Aa SN increased TL proliferation. This mitogenic effect of Aa SN was attenuated by pretreating TL with indomethacin (INDO) or acetylsalicylic acid (ASA) but not by polymyxin B. The inhibitory effect of INDO on cell proliferation was reversed by the addition of prostaglandin E2 (PGE2) to the culture assay. Moreover, when immune cells were exposed to Aa SN they were able to generate PGE2 at the same time as intracellular levels of cAMP decreased. Both, PGE2 release and decrease accumulation of cAMP in TL were blunted by treated lymphocytes with INDO. In this paper we demonstrate that cell free SN from Aa induces a mitogenic effect on murine lymphocytes. The mechanism involves the host's immunecompetent cells and the release of PGE2 and appears not to be induced by capsular-like polysaccharide antigen. Results show a paradoxical mitogenic effect of Aa SN accompanied by increased generation of PGE2 and decreased production of cAMP by lymphocytes.

Vascular endothelial growth factor (VEGF) in Crohn's disease: increased production by peripheral blood mononuclear cells and decreased VEGF165 labeling of peripheral CD14+ monocytes

Recently, increased serum levels of vascular endothelial growth factor (VEGF) have been shown in patients with inflammatory bowel disease. The origins of the circulating VEGF are still not described. Monocytes play an important role in the inflammatory process. VEGF binding to monocytes mediates monocyte recruitment and activation. The present study investigates the VEGF production of peripheral blood mononuclear cells and the ability of peripheral monocytes to bind VEGF165 in patients with Crohn's disease. Nineteen patients with Crohn's disease and 10 healthy volunteers were studied. VEGF165 labeling of CD14+ monocytes was measured using two-color flow cytometry. Density of VEGF labeling was expressed as the mean fluorescence intensity (MFI). Furthermore, VEGF levels were determined in culture supernatants of unstimulated peripheral blood mononuclear cells. VEGF in culture supernatants was measured using a solid-phase enzyme-linked immunosorbent assay. There was a significantly decreased VEGF165 labeling of monocytes of patients with active Crohn's disease (MFI: 369.9+/-121.6, N = 7, P < 0.002) compared to patients with inactive disease (MFI: 457.7+/-74.5, N = 6) and healthy controls (MFI: 542.9+/-96.2, N = 10). Unstimulated peripheral blood mononuclear cells of patients with active Crohn's disease produced significantly higher amounts of VEGF (1142.6+/-483.9 pg/ml, N = 12, P < 0.001) compared with peripheral blood mononuclear cells of healthy volunteers (113.4+/-101.8 pg/ml, N = 10). VEGF production by peripheral blood mononuclear cells of patients with active disease was significantly increased compared to patients with quiescent disease (261.6+/-254.8 pg/ml, N = 7, P < 0.001). In conclusion, our data describe peripheral blood mononuclear cells as one of the origins of the elevated VEGF serum levels in patients with active Crohn's disease. Furthermore, a decrease in VEGF165 binding sites on peripheral monocytes of patients with active Crohn's disease has been shown. The study underlines the important role of VEGF in Crohn's disease.

Treatment of port-wine stains with a noncoherent pulsed light source: a retrospective study

OBJECTIVE

We investigated whether a noncoherent intense pulsed light source (IPLS) would be effective in therapy of port-wine stains (PWSs).

DESIGN

To evaluate the efficacy in treatment of PWSs with IPLS, a retrospective study was initiated.

SETTING

The data were collected by physicians working in private practices and departments of university hospitals and medical centers, respectively.

PATIENTS

A total of 37 randomly selected patients with a total of 40 PWSs were included in the study. Clinical PWS characteristics recorded were color and location of the PWS.

INTERVENTIONS

All patients were treated with IPLS.

MAIN OUTCOME MEASURES

Data collected included treatment parameter (filters, pulse duration, fluence, and pulse sequencing), percentage of clearance, and side effects (purpura, blisters, crusting, altered pigmentation, and scarring).

RESULTS

Good and complete (70%-100%) clearance was achieved in 28 of 40 PWSs treated with IPLS. The average number of treatment sessions in PWSs reaching 100% clearance included 4.0 for pink PWSs and 1.5 for red PWSs. The average number of sessions for purple PWSs reaching good clearance (70%-99%) was 4.2 sessions. Parameters used most frequently were 515- and 550-nm cut-off filters, pulse duration of 2.5 to 5.0 milliseconds, and fluences of 24 to 60 J/cm2. Side effects included purpura in 133 (76%), superficial blisters in 14 (8%), and crusting in 35 (20%). Transient pigmentation changes were seen in 10.8% of patients (hypopigmentation in 3 [8.1%], hyperpigmentation in 1 [2.7%]). No scarring was observed.

CONCLUSION

Intense pulsed light source presents an effective and safe method for treating PWSs, especially purple PWSs.

Cloning of novel injury-regulated genes. Implications for an important role of the muscle-specific protein skNAC in muscle repair

To gain insight into the molecular mechanisms underlying the wound repair process, we searched for genes that are regulated by skin injury. Using the differential display reverse transcription-polymerase chain reaction technique, we identified a gene that was strongly induced as early as 12 h after wounding. Sequence analysis revealed the identity of the corresponding protein with skeletal muscle nascent polypeptide-associated complex (skNAC), a recently identified muscle-specific transcription factor. By in situ hybridization and immunohistochemistry, we demonstrated the specific expression of skNAC in skeletal muscle cells of the panniculus carnosus at the wound edge. Furthermore, in vitro studies with cultured myoblasts revealed expression of skNAC in differentiating and differentiated, but not in proliferating, nondifferentiated cells. Differentiation of cultured myoblasts was accompanied by simultaneous expression of skNAC and the muscle-specific transcription factor myogenin. Our results provide the first evidence for a role of skNAC in muscle repair processes. Furthermore, they demonstrate the usefulness of our approach in identifying new players in wound repair.

[A Scandinavian multicenter study will investigate the question: surgery or not in mild primary hyperparathyroidism?]

Primary hyperparathyroidism is a common endocrine disease particularly prevalent among elderly women. A majority of these patients diagnosed today are mildly hypercalcaemic, and many seem to lack manifest symptoms or complications. In such cases, conservative follow-up rather than parathyroid surgery may be suggested. However, long-term follow-up may entail costly investigations and be difficult to accomplish. Moreover, conservative follow-up is associated with a risk of subsequent complications or even premature death due to cardiovascular disorders. A Scandinavian multicentre study has been initiated to assess survival, morbidity and quality of life in surgically vs. conservatively treated patients.

Different types of ROS-scavenging enzymes are expressed during cutaneous wound repair

Injury to the skin initiates a series of events including inflammation, new tissue formation, and matrix remodeling. During the early inflammatory phase, polymorphonuclear leukocytes and macrophages infiltrate the wounded tissue. Once activated, they produce large amounts of reactive oxygen species (ROS) as part of their defense mechanism. Although this process is beneficial, increased levels of ROS can inhibit cell migration and proliferation and can even cause severe tissue damage. Therefore, cells must develop strategies for the detoxification of these molecules. To gain insight into the mechanisms which underlie this process, we analyzed the temporal and spatial expression pattern of various ROS-scavenging enzymes during the healing process of full-thickness excisional wounds in mice. Here we demonstrate a strong mRNA expression of two types of superoxide dismutase (SOD), as well as of catalase, and the selenoenzymes glutathione peroxidase (SeGPx) and phospholipid hydroperoxide glutathione peroxidase in normal and wounded skin. Most importantly, mRNA levels of the SODs and of SeGPx increased strongly after skin injury. In situ hybridization and immunofluorescence studies revealed the presence of these transcripts at multiple places in the wound, whereby particularly high expression levels were detected in the hyperproliferative epithelium and the hair follicles at the wound edge. These data suggest an important role of ROS-scavenging enzymes in the detoxification of ROS during cutaneous wound repair.

Consequences of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor blockade during status epilepticus in the developing brain

To investigate if AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor activation contributes to acute manifestations and long term consequences of status epilepticus (SE), we administered the AMPA receptor antagonist NBQX to P35 rats undergoing kainic acid (KA)-induced SE. NBQX (30 mg/kg/dose) given intraperitoneally (i.p.) at 30, 60 and 90 min after i.p. KA injection (12 mg/kg) reduced severity of SE. When tested as adults, rats that had received KA and NBQX were similar to controls with no long term impairment in visuospatial memory (assessed by the water maze test), or histologic damage in the CA1 or CA3 hippocampal subfields. However, both P35 groups, those receiving KA alone and those receiving KA and NBQX, had similar rates of spontaneous recurrent seizures (SRS). In P15 rats, NBQX resulted in increased acute mortality from KA associated SE. These results indicate that the effects of NBQX on KA-induced SE are age dependent, and that non-NMDA receptor activation contributes to the acute manifestations and to the long term sequelae seen after KA-induced SE in the prepubescent rat brain.

[Tattoo removal Q-switched ruby laser (694 nm) and the Q-switched Nd:YAG laser (532 and 1064 nm). A retrospective study]

In a retrospective study 47 patients with 68 amateur and 25 professional tattoos were examined, considering clearance of tattoo pigments and the frequency of side effects after finished treatments with the Q-switched ruby (694 nm) and the Q-switched Nd:YAG laser (532 and 1064 nm). Black amateur tattoos were found to lighten faster than professional tattoos (13.2 and 18.6 treatments respectively). For the clearance of multicolored tattoos (amateur or professional), similar numbers of laser treatments were needed. Green pigments were removed with the Q-switched ruby laser and red pigments with the frequency-doubled Nd:YAG laser (532 nm). Compared to the Q-switched Nd:YAG laser (1064 nm), the Q-switched ruby laser and the frequency-doubled Nd:YAG laser (532 nm) more often caused blistering and transient hypopigmentation (5.4% and 7.5% vs. 1.1% (blisters); 8.6% and 15.1% vs. 4.3% (hypopigmentation).

Activin: a novel player in tissue repair processes

Recent studies have demonstrated a strong expression of activin in repair processes of various tissues and organs, including the skin, the lung, the intestine, the cardiovascular system, and even the brain. Although little is as yet known about the function of activin in tissue repair, first results suggest a role of activin in epithelial differentiation, fibroblast proliferation and expression of matrix molecules by these cells, and also in neuroprotection. Whereas a transient overexpression of activin after tissue injury might be beneficial for the repair process, sustained expression of activin could lead to fibrotic processes. Therefore, the modulation of the availability or biological activity of activin could be of particular importance for the treatment of impaired tissue repair on the one hand and tissue fibrosis on the other hand.

Induction of inducible nitric oxide synthase and its corresponding tetrahydrobiopterin-cofactor-synthesizing enzyme GTP-cyclohydrolase I during cutaneous wound repair

Recent work has suggested a possible role of nitric oxide, a free radical gas, during the wound healing process. In this study we investigated the regulation of inducible nitric oxide synthase (iNOS) and GTP-cyclohydrolase I (GTP-CH I), the rate-limiting enzyme in the biosynthesis of the iNOS cofactor (6R) 5,6,7,8-tetrahydrobiopterin (6-BH4), during the repair process. We found a similar time course of induction of iNOS and GTP-CH I expression, whereas absolute expression levels were different for both genes. Immunohistochemical analysis revealed colocalization of iNOS and GTP-CH I proteins in the wound. Systemic treatment with glucocorticoids significantly altered the expression levels of iNOS and GTP-CH I. Expression of iNOS and GTP-CH I was suppressed by glucocorticoids in normal, and to a much greater extent in wounded skin. Furthermore, a role of nitric oxide as a novel mediator of gene regulation during healing is suggested by the demonstration of nitric oxide-mediated induction of vascular endothelial growth factor expression in keratinocytes. These findings may provide an explanation for the beneficial effects of orally supplemented L-arginine on wound healing, and suggest that a disturbed induction of iNOS and GTP-CH I expression may at least partially underlie the wound healing defect seen in glucocorticoid-treated animals.

Pressure-Induced Order–Disorder Phase Transition of Spinel Single Crystals

The present study deals with single-crystal structure investigations by means of X-ray scattering of a pressure-induced phase transition of Mg0.4Al2.4O4. The compressibility of the substance is very small, whereas the structural changes are surprisingly high. A non-identified high-pressure phase turns out to be reversible considering the existence of a spinel single crystal, but not reversible with regard to the ordering of the cations in the oxygen framework. The pressure-induced disordering of the cations is preserved on abrupt pressure decrease and can be detected in a recovered specimen.

Q-switched ruby laser treatment of tattoos and benign pigmented skin lesions: a critical review

The Q-switched ruby laser (694 nm, 25-40 nsec) is an effective and safe therapeutic device for the treatment of tattoos and well-defined, benign, pigmented epidermal and dermal lesions. Because of its selective mode of action, dermal pigments of natural and artificial origin are destroyed photothermically and removed without scar. This method is exceptionally suited for the elimination of lay and professional tattoos, traumatic tattoos, and permanent makeup. Other frequent indications include benign pigmented lesions such as lentigines, freckles, café-au-lait spots, seborrheic keratosis, and Becker nevi. As a dermal pigmented lesion, the nevus of Ota is perfectly treatable. However, chloasma can no longer be considered an indication for ruby laser treatment due to unsatisfactory results. Melanocytic nevi and congenital nevi should be treated only in clinical studies. The effectiveness of the long-term epilation of dark hair with this laser device has to be verified in future investigations. Particularly attractive is the nonproblematic and straightforward removal of pigmented lesions in precarious anatomic regions like the lips, eyelids, and genitals (e.g., benign melanosis of the lips or of the penis, seborrheic keratosis of the lid angle).

Connective tissue growth factor: a novel regulator of mucosal repair and fibrosis in inflammatory bowel disease?

Inflammatory bowel disease (IBD) is a multifactorial disorder which is characterized by massive damage of the epithelium and the underlying mesenchyme of the intestine. Due to the potent effect of connective tissue growth factor (CTGF) on fibroblast proliferation and connective tissue deposition we speculated about a possible role of this mitogen in IBD. Here we demonstrate a strikingly increased expression of CTGF mRNA in surgical specimens of patients suffering from two forms of IBD, Crohn's disease and ulcerative colitis. In most specimens, the levels of CTGF mRNA correlated with the degree of inflammation as assessed by histological analysis of adjacent tissue samples and by expression analysis of the pro-inflammatory cytokine interleukin-1 beta. However, areas of little inflammation which were characterized by severe fibrosis also revealed high levels of CTGF mRNA. Expression of transforming growth factor beta-1 (TGF-beta 1), the only known inducer of CTGF so far, as well as of the CTGF target genes collagen I alpha 1, fibronectin and integrin alpha 5 revealed a strong correlation with the expression of CTGF. These data suggest a prominent role of CTGF in the repair of mucosal injury in IBD and in the aberrant deposition of extracellular matrix leading to fibrosis and stenosis, one major complication in IBD, especially in Crohn's disease.

Dexamethasone is a novel potent inducer of connective tissue growth factor expression. Implications for glucocorticoid therapy

Due to its potent effect on fibroblast proliferation and extracellular matrix deposition, connective tissue growth factor (CTGF) seems to play an important role in the pathogenesis of fibrotic disease. Since glucocorticoids are frequently used for the therapy of these disorders, we determined a potential effect of these steroids on CTGF expression. In cultured fibroblasts, a striking induction of CTGF expression was observed after dexamethasone treatment and occurred in a time- and dose-dependent manner. This effect was obviously not mediated by the CTGF inducer transforming growth factor-beta1, since expression of this factor was down-regulated by the glucocorticoid. Most importantly, CTGF expression levels also increased substantially in various tissues and organs by systemic glucocorticoid treatment of mice. After cutaneous injury, a strong induction of CTGF expression was seen in the wounds of nontreated mice. However, no further increase in the levels of CTGF mRNA occurred in wounded skin compared with unwounded skin of glucocorticoid-treated animals, suggesting the presence of other factors in the wound that might compensate for the effect of the steroids. Tumor necrosis factor-alpha was identified as a possible mediator of this effect because this factor suppressed CTGF expression in cultured fibroblasts and also blocked the glucocorticoid-induced CTGF production by these cells. These findings indicate that glucocorticoids stimulate CTGF expression in normal tissues and organs but not in highly inflamed areas.

Matrix metalloproteinases (MMPs) and their physiological inhibitors (TIMPs) are differentially expressed during excisional skin wound repair

During cutaneous wound healing a number of migratory and remodeling events occur that require the action of matrix metalloproteinases (MMPs) and their natural inhibitors (TIMPs). In this study, we analyzed the temporal and spatial expression patterns of these molecules during the healing of murine excisional skin wounds. Our data imply that defined phases of repair rely on distinct repertoires of MMP activity and TIMP counterregulation. Reepithelialization was found to be associated with active production of collagenase, 92-kDa gelatinase, and stromelysins-1 and -2 by distinct subpopulations of keratinocytes at the migrating border. Notably, no TIMP transcripts were expressed in the epidermis, but TIMP-1 expression in the wound colocalized with expression of collagenase, 92-kDa gelatinase, and stromelysin-1, albeit in distinct cells. Concomitant with the formation of an extensive hyperproliferative epithelium, TIMP-1 transcripts accumulated at the mesenchymal/epidermal border of the granulation tissue. During later phases of wound repair, we observed an increase in 72-kDa gelatinase and MT1-MMP expression, whereby the transcripts of these colocalizing MMPs were detected exclusively and at high levels in the granulation tissue. At completion of reepithelialization, the expression levels of the MMPs and TIMP-1 seen in epidermal and dermal compartments declined to near-basal levels, whereas the macrophage-specific metalloelastase (MME) reached maximum expression. In reepithelialized wound tissue, MME transcripts were detected in deep layers of reconstituted dermis and seemed to cluster around vascular structures. Systemic glucocorticoid treatment, which is known to result in impaired wound healing, led to a nearly complete shut-off of MME expression. These observations imply an additional role of macrophage-related proteolysis, independent of its classical roles during earlier, inflammatory phases of cutaneous wound repair.