Thinning of specific retinal layers as a novel biomarker for adverse outcomes in high-risk pregnancy.

PURPOSE: To investigate a potential association between retinal layer thinning and pregnancy-related adverse outcomes. METHODS: A prospective observational study included 32 pregnant women between the ages of 18 and 45. Seventeen had uneventful pregnancies, and 15 experienced an adverse obstetrical outcome. Macular swept-source ocular coherence tomography was performed, and selective layers of the retina were evaluated. Adverse obstetrical outcome was defined as any of the following: preterm delivery, preeclampsia, pregnancy-induced hypertension, elevated liver function tests, thrombocytopenia and need for magnesium. RESULTS: The inner superior ganglion cell layer (GCL) was found to be thinner in the cohort with composite adverse obstetrical outcomes than in the cohort without complications (84.5±6.9 vs. 89.5±6.1µm respectively; P=0.04). Total inner superior (295.5±39.1 vs. 302.5±12.7µm; P=0.03) and inferior retinal thickness (289.0±13.9 vs. 301.0±17.1µm; P=0.03) as well as total macular volume (7.5±0.3 vs. 7.7±0.3 mm3; P=0.02) were also lower in women with adverse obstetrical outcomes. CONCLUSION: Thinning of the macular ganglion cell layer was associated with adverse outcomes in pregnancy. Larger studies are necessary to assess the potential role of macular GCL analysis in pregnancy.

Biochemical control and toxicity for favorable- and intermediate-risk patients using real-time intraoperative inverse optimization prostate seed implant: Less is more!

PURPOSE: To report the biochemical control rate and clinical outcomes with real-time inverse planning (inverse optimization prostate seed implant [IO-PSI]) for favorable-risk (FR) and intermediate-risk (IR) prostate adenocarcinoma in a community practice setting. This analysis is an extended followup of our initial report, with favorable early biochemical control rate (biochemical nonevidence of disease) of 97% at 4 years. METHODS AND MATERIALS: Three hundred fifty-seven evaluable patients with FR and IR prostate cancer underwent real-time IO-PSI (iodine-125/145 Gy or palladium-103/120 Gy) between 2001 and 2013. RESULTS: With a median followup of 54 months (range, 24-110 months), the absolute biochemical failure free survival of disease was 96%. The 8-year actuarial probability of prostate-specific antigen failure-free survival for FR and IR cohorts was 92.4% and 87%, respectively. Late genitourinary and gastrointestinal toxicity remained low. Late Grade 2 and Grade 3 genitourinary toxicity was 19% and 1%, respectively. Late Grade 2 and 3 rectal bleeding rates were 1% and 0%, respectively. No difference in biochemical control was observed with preimplant short course androgen deprivation or between Gleason score 3 + 4 vs. 4 + 3 patients. No dosimetric parameter was predictive of biochemical failure. Patients with FR had a significantly decreased risk of failure (hazard ratio = 0.26; 95% confidence interval = 0.09-0.78; p = 0.02) compared with those with IR. Patients with a prostate-specific antigen nadir >0.4 ng/mL had an increased risk of failure (hazard ratio = 1.37; 95% confidence interval = 1.27-1.47; p < 0.0001). CONCLUSIONS: Our initial biochemical and clinical outcomes using real-time IO-PSI persisted with extended followup and support our original hypothesis for use of a reduced number of sources, needles, and total activity, suggesting that with IO, less is more.

A review of community management of paediatric burns.

This study was a component of a broader review to evaluate burn care in South Africa. A prospective audit of 353 children with thermal injuries admitted to the Red Cross War Memorial Children's Hospital in Cape Town was performed during 2012/2013. The audit was based to assess the adherence of initial burn management to the provincial policy guidelines on the clinical management of the burn wound. The community management of each patient prior to admission to a burns centre was assessed for the following: basic demographics, emergency home management, wound cover, analgesia and transport to medical facilities. Their ages ranged from 1 month to 14 years. The average total body surface area [TBSA] was 15% [1-86%]. Most of the injuries were due to hot water accidents [78.5%] followed by flame burns (9%), direct contact and electricity burns. Two hundred and twenty five children [63%] received first aid measures at home, including cooling with water [166] ice [30] and a cooling agent. No cooling was instituted in 130 and 65% of the patient's wounds were cooled for 10 min or less. Eighty percent proceeded to the referral centre or burns unit without their wounds being covered; with only 19 patients having any medical type of dressing available at home. Two hundred and ninety five children [83.6%] received pain medication prior to admission at the burns unit. Of the 316 patients not directly attending the burns unit, 137 received i.v. fluids of which 95 had burns greater than 10% TBSA. None of the patients were in shock on admission and all i.v. lines were functioning. Forty-four children with burns greater than 10% did not receive i.v. fluids. The audit identified six factors that were inadequately addressed during the pre-admission period: first aid, cooling of the wound, early covering of the wound, resuscitation, pain management and transfer. If these could be readdressed, basic burn care would be substantially improved in the study area.

PPARß/δ promotes HRAS-induced senescence and tumor suppression by potentiating p-ERK and repressing p-AKT signaling.

Peroxisome proliferator-activated receptor-ß/δ (PPARß/δ) inhibits skin tumorigenesis through mechanisms that may be dependent on HRAS signaling. The present study examined the hypothesis that PPARß/δ promotes HRAS-induced senescence resulting in suppression of tumorigenesis. PPARß/δ expression increased p-ERK and decreased p-AKT activity. Increased p-ERK activity results from the dampened HRAS-induced negative feedback response mediated in part through transcriptional upregulation of RAS guanyl-releasing protein 1 (RASGRP1) by PPARß/δ. Decreased p-AKT activity results from repression of integrin-linked kinase (ILK) and phosphoinositide-dependent protein kinase-1 (PDPK1) expression. Decreased p-AKT activity in turn promotes cellular senescence through upregulation of p53 and p27 expression. Both over-expression of RASGRP1 and shRNA-mediated knockdown of ILK partially restore cellular senescence in Pparß/δ-null cells. Higher PPARß/δ expression is also correlated with increased senescence observed in human benign neurofibromas and colon adenoma lesions in vivo. These results demonstrate that PPARß/δ promotes senescence to inhibit tumorigenesis and provide new mechanistic insights into HRAS-induced cellular senescence.

Expression profile of skin papillomas with high cancer risk displays a unique genetic signature that clusters with squamous cell carcinomas and predicts risk for malignant conversion.

Chemical induction of squamous tumors in the mouse skin induces multiple benign papillomas: high-frequency terminally benign low-risk papillomas and low-frequency high-risk papillomas, the putative precursor lesions to squamous cell carcinoma (SCC). We have compared the gene expression profile of twenty different early low- and high-risk papillomas with normal skin and SCC. Unsupervised clustering of 514 differentially expressed genes (P<0.001) showed that 9/10 high-risk papillomas clustered with SCC, while 1/10 clustered with low-risk papillomas, and this correlated with keratin markers of tumor progression. Prediction analysis for microarrays (PAM) identified 87 genes that distinguished the two papilloma classes, and a majority of these had a similar expression pattern in both high-risk papillomas and SCC. Additional classifier algorithms generated a gene list that correctly classified unknown benign tumors as low- or high-risk concordant with promotion protocol and keratin profiling. Reduced expression of immune function genes characterized the high-risk papillomas and SCC. Immunohistochemistry confirmed reduced T-cell number in high-risk papillomas, suggesting that reduced adaptive immunity defines papillomas that progress to SCC. These results demonstrate that murine premalignant lesions can be segregated into subgroups by gene expression patterns that correlate with risk for malignant conversion, and suggest a paradigm for generating diagnostic biomarkers for human premalignant lesions with unknown individual risk for malignant conversion.

Conditional epidermal expression of TGFbeta 1 blocks neonatal lethality but causes a reversible hyperplasia and alopecia.

To study the role of transforming growth factor type beta1 (TGFbeta1) in epidermal growth control and disease, we have generated a conditional expression system by using the bovine keratin 5 promoter to drive expression of the tetracycline-regulated transactivators tTA and rTA, and a constitutively active mutant of TGFbeta1 linked to the tetO target sequence for the transactivator. This model allows for induction or suppression of exogenous TGFbeta1 with oral doxycycline. Maximal expression of TGFbeta1 during gestation caused embryonic lethality, whereas partial suppression allowed full-term development with neonatal lethality characterized by runting, epidermal hypoproliferation, and blocked hair follicle growth. With complete suppression, phenotypically normal double transgenic (DT) mice were born. Acute induction of TGFbeta1 in the epidermis of adult mice inhibited basal and follicular keratinocyte proliferation and reentry of telogen hair follicles into anagen. However, chronic expression of TGFbeta1 in adult DTs caused severe alopecia characterized by epidermal and follicular hyperproliferation, apoptosis, as well as dermal fibrosis and inflammation. Readministration of doxycycline to tTA DT mice caused hair regrowth within 14 days. The mRNA and protein for Smad7, an inhibitor of TGFbeta signaling, were up-regulated in the epidermis and hair follicles of alopecic skin and rapidly induced in rTA mice in parallel with the TGFbeta1 transgene, suggesting that the hyperproliferative phenotype may result in part from development of a sustained negative feedback loop. Thus, this conditional expression system provides an important model for understanding the role of TGFbeta1 during development, in normal skin biology, and in disease.

The adenosine triphosphate test: a bedside diagnostic tool for identifying the mechanism of supraventricular tachycardia in patients with palpitations.

OBJECTIVES: This study assesses the value of the "ATP test" (injection of adenosine triphosphate [ATP] during sinus rhythm) for identifying patients with palpitations of unclear etiology who actually have atrioventricular (AV) nodal re-entry tachycardia (AVNRT) or AV re-entry tachycardia (AVRT). BACKGROUND: Because AVNRT and AVRT can be cured with radiofrequency ablation, documentation of spontaneous AVNRT or AVRT usually prompts referral for electrophysiologic (EP) evaluation. However, these paroxysmal arrhythmias may elude clinical diagnosis. We recently showed that administration of ATP during sinus rhythm often reveals dual AV node physiology or a concealed accessory pathway (AP) in patients with documented AVNRT or AVRT. Thus, we postulated that the ATP test could identify patients with palpitations who actually have AVNRT or AVRT and would therefore benefit from EP evaluation. METHODS: One hundred forty-six patients (54 with "palpitations without documented arrhythmias" and 92 with "documentation of arrhythmias of unclear mechanism") underwent a noninvasive ATP test. ATP was injected during sinus rhythm using 10 mg increments. The ATP test was considered positive when prospectively defined signs of dual AV node physiology or concealed AP were disclosed in the electrocardiogram. These findings were correlated with the results of EP evaluation. RESULTS: A positive ATP test predicted induction of AVNRT or AVRT with a positive predictive value of 93% (sensitivity 71%) but a negative predictive value of 37% (specificity 76%). CONCLUSIONS: A bedside ATP test identifies patients with palpitations who are likely to have AVNRT or AVRT (and who are therefore likely to benefit from EP evaluation) with a high positive predictive value.

Increased sensitivity of transforming growth factor (TGF) beta 1 null cells to alkylating agents reveals a novel link between TGFbeta signaling and O(6)-methylguanine methyltransferase promoter hypermethylation.

Inactivation of the transforming growth factor beta (TGFbeta)-signaling pathway and gene silencing through hypermethylation of promoter CpG islands are two frequent alterations in human and experimental cancers. Here we report that nonneoplastic TGFbeta1-/- keratinocyte cell lines exhibit increased sensitivity to cell killing by alkylating agents, and this is due to lack of expression of the DNA repair enzyme O(6)-methylguanine DNA methyltransferase (MGMT). In TGFbeta1-/- but not TGFbeta1+/- cell lines, the CpG dinucleotides in the MGMT promoter are hypermethylated, as measured by restriction enzyme analysis and methylation specific polymerase chain reaction. In one unstable TGFbeta1+/- cell line, loss of the wild type TGFbeta1 allele correlates with the appearance of methylation in the MGMT promoter. Bisulfite sequencing shows that in the KO3 TGFbeta1-/- cell line nearly all of the 28 CpG sites in the MGMT promoter 475 base pairs upstream of the start site of transcription are methylated, whereas most are unmethylated in the H1 TGFbeta1+/- line. Treatment of the TGFbeta1-/- cell lines with 5-azacytidine causes reexpression of MGMT mRNA and demethylation of CpG islands in the promoter. Analysis of the time course of methylation using methylation-specific polymerase chain reaction shows a lack of methylation in primary TGFbeta1-/- keratinocytes and increasing methylation with passage number of immortalized clones. Subcloning of early passage clones reveals a remarkable heterogeneity and instability of the methylation state in the TGFbeta1-/- keratinocytes. Thus, the TGFbeta1-/- genotype does not directly regulate MGMT methylation but predisposes cells to immortalization-associated MGMT hypermethylation.

Activator protein 1 transcription factors are fundamental to v-rasHa-induced changes in gene expression in neoplastic keratinocytes.

The induction of mouse skin papillomas by initiation-promotion protocols is associated with aberrant expression of epithelial markers in the tumor mass. Similarly, initiation of mouse keratinocytes with a retrovirus encoding the v-rasHa gene (v-rasHa keratinocytes) causes characteristic alterations of epidermal gene expression (A. A. Dlugosz et at, Cancer Res., 54: 6413-6420, 1994). Because activator protein 1 (AP-1) proteins are likely targets of Ras activation, we have examined the role of AP-1 factors in v-rasHa keratinocytes. Introduction of v-rasHa into keratinocytes up-regulates c-Fos, deltaFos B, and Fra-1 transcripts and protein levels in nuclear extracts. The expression of Jun proteins is not significantly altered in v-rasHa keratinocytes. Transduction of cells with v-rasHa results in increased AP-1-dependent transcriptional activity, which is also simulated by transfection of keratinocytes with either c-Fos or deltaFos B but not Fra-1, suggesting that the up-regulation of c-Fos and deltaFos B contributes to this effect. To explore the role of AP-1 proteins in regulating keratinocyte markers in v-rasHa keratinocytes, we blocked the binding of AP-1 proteins to DNA by infecting keratinocytes with an adenovirus encoding a dominant-negative Fos mutant (A-FOS). A-FOS replaces endogenous Fos proteins in the formation of heterodimers with Jun family members and thus prevents the AP-1 transcription factor from binding to DNA. In v-rasHa keratinocytes, the A-FOS virus reversed the suppression of keratins 1 and 10 transcripts and protein, which is characteristically seen in tumors and v-rasHa keratinocytes. A-FOS also increased protein levels but reduced transcripts for the late marker, loricrin, a component of the cornified envelope. These findings indicate that AP-1 proteins are involved in the changes in gene expression that define the v-rasHa phenotype in mouse keratinocytes.

Conditional gene expression in the epidermis of transgenic mice using the tetracycline-regulated transactivators tTA and rTA linked to the keratin 5 promoter.

To produce conditional expression of genes in the mouse epidermis we have generated transgenic mouse lines in which the tetracycline-regulated transcriptional transactivators, tTA and rTA, are linked to the bovine keratin 5 promoter. The transactivator lines were crossed with the tetOlacZ indicator line to test for transactivation in vivo. In the absence of doxycycline, the K5/tTA line induced beta-galactosidase enzyme activity in the epidermis at a level 500-fold higher than controls, and oral and topical doxycycline caused a dose- and time-dependent suppression of beta-galactosidase mRNA levels and enzyme activity. In the K5/rTA lines, doxycycline induced beta-galactosidase activity between 3- and 50-fold higher depending on the founder line, and this occurred within 24-48 h after dosing. Histochemical analysis of all lines localized beta-galactosidase expression to the basal layer of the epidermis and the outer root sheath of the hair follicle, as well as other keratin 5 positive tissues. In several K5/rTA lines, skin-specific transactivation was restricted to the hair follicle. Treatment of these double transgenic mice with 12-O-tetradecanoyl-phorbol-13-acetate caused rapid migration of beta-galactosidase marked cells from the hair follicle through the interfollicular epidermis, demonstrating the usefulness of this specific double transgenic for fate mapping cells in the epidermis. These results show that the tetracycline regulatory system produces effective conditional gene expression in the mouse epidermis, and suggest that it should be amenable to suppression and activation of foreign genes during development and specific pathologic conditions relevant to the epidermis.

Rate smoothing with cardiac pacing for preventing torsade de pointes.

Cardiac pacing remains one of the most effective means for preventing torsade de pointes in patients with long QT syndrome (LQTS). However, fatal arrhythmias may occur despite combined therapy with beta blockers and pacing, and it is possible that failure of cardiac pacing for preventing arrhythmias in the long run is related (at least in part) to suboptimal pacemaker programming. Preventing sudden pauses may be especially important for preventing arrhythmias in the LQTS because such pauses are highly proarrhythmic in this patient population. Unfortunately, properly functioning pacemakers cannot be expected to prevent postextrasystolic pauses. The use of a pause-prevention pacing algorithm-rate smoothing-for preventing pause-dependent torsade de pointes is described in 12 patients with cardiac arrest or syncope due to congenital LQTS who were followed for 21 +/- 11 months.

Adenosine-5'-triphosphate test for the noninvasive diagnosis of concealed accessory pathway.

OBJECTIVES: This study assessed the use of adenosine triphosphate (ATP) in the noninvasive diagnosis of concealed accessory pathway (AP) and dual atrioventricular (AV) node physiology in patients with inducible AV reentrant tachycardia (AVRT). BACKGROUND: Administration of ATP during sinus rhythm identifies dual AV node physiology in 76% of patients with inducible sustained slow/fast AV nodal reentry tachycardia (AVNRT). METHODS: Incremental doses of ATP were intravenously administered during sinus rhythm to 34 patients with inducible sustained AVRT involving a concealed AP and to 27 control patients without AP or dual AV node physiology. One study group patient could not complete the study and was excluded from analysis. RESULTS: The AV reentrant echo beats (AVRE), or AVRT, suggestive of the presence of concealed AP, were observed after ATP administration in 24 (73%) study patients and in none of the control group. Electrocardiographic signs suggestive of dual AV node physiology were observed after ATP administration in 7 (21%) study patients and in none of the control group. Most instances of AVRE/AVRT were preceded by a slight increase (<50 ms) in PR interval. In 8 of 9 patients tested, neither AVRE nor AVRT was no longer observed following ATP administration after successful radiofrequency ablation of the AP. In the remaining patient, a different AVRE due to the presence of an additional AP was observed. CONCLUSIONS: Administration of ATP during sinus rhythm may be a useful bedside test for identifying patients with concealed AP who are prone to AVRT and those with associated dual AV node pathways.

Prevalence of the Brugada sign in idiopathic ventricular fibrillation and healthy controls.

OBJECTIVE: To determine the prevalence of the Brugada sign (right bundle branch block with ST elevation in V1-V3) in idiopathic ventricular fibrillation and in an age matched healthy population. DESIGN: ECGs from 39 consecutive patients with idiopathic ventricular fibrillation and 592 healthy controls were reviewed. They were classified as definite, questionable, and no Brugada sign (according to predetermined criteria) by four investigators blinded to the subjects' status. RESULTS: Eight patients (21%) with idiopathic ventricular fibrillation but none of the 592 controls had a definite Brugada sign (p < 0.005). Thus the estimated 95% confidence limits for the prevalence of a definite Brugada sign among healthy controls was less than 0.5%. A questionable Brugada sign was seen in two patients with idiopathic ventricular fibrillation (5%) but also in five controls (1%) (p < 0.05). Normal ECGs were found following resuscitation and during long term follow up in 31 patients with idiopathic ventricular fibrillation (79%). Patients with idiopathic ventricular fibrillation and a normal ECG and those with the Brugada syndrome were of similar age and had similar spontaneous and inducible arrhythmias. However, the two groups differed in terms of sex, family history, and the incidence of sleep related ventricular fibrillation. CONCLUSIONS: A definite Brugada sign is a specific marker of arrhythmic risk. However, less than obvious ECG abnormalities have little diagnostic value, as a "questionable" Brugada sign was observed in 1% of healthy controls. In this series of consecutive patients with idiopathic ventricular fibrillation, most had normal ECGs.

Simplified "ATP test" for noninvasive diagnosis of dual AV nodal physiology and assessment of results of slow pathway ablation in patients with AV nodal reentrant tachycardia.

INTRODUCTION: We recently reported that administration of adenosine triphosphate (ATP) during sinus rhythm identifies dual AV nodal physiology (DAVNP) in 76% of patients with inducible sustained AV nodal reentrant tachycardia (AVNRT) at electrophysiologic (EP) study. In that report, however, the ATP test was considered positive for DAVNP only when the results were reproducible at a given dose of ATP. The aim of the present study was to assess the value of a simplified ATP test for noninvasive diagnosis of DAVNP and abolition or modification of the slow pathway (SP) after radiofrequency ablation (RFA) in patients with inducible sustained AVNRT. METHODS AND RESULTS: The value of a single dose of ATP was studied in 105 patients with inducible sustained AVNRT and in 31 control patients before placement of EP catheters in the cardiac chambers. ATP (10 to 60 mg, in 10-mg increments) was injected during sinus rhythm until ECG signs of DAVNP (> or = 50 msec increase or decrease in PR interval in two consecutive beats, or occurrence of > or = 1 AV nodal echo beat) or > or = second-degree AV block was observed. DAVNP was observed in only 1 (3.2%) control patient. The test could be completed in 96 study patients. DAVNP was found by ATP test in 72 (75%) patients, whereas it was diagnosed by EP criteria in 82 (85%) patients. DAVNP by ATP test disappeared in 27 (96%) of 28 patients who underwent SP abolition and in 18 (60%) of 30 patients who underwent SP modification. In the 12 patients with persistent DAVNP determined by ATP test after SP modification, the number of beats conducted over the SP was significantly reduced (from 6.3+/-3.3 to 2.5+/-2.2 beats; P = 0.002). CONCLUSION: A single administration of ATP during sinus rhythm (at a given dose) enables noninvasive diagnosis of DAVNP in a high percentage of patients with inducible AVNRT and reliably confirms the results of RFA of the SP.

Defects in TGF-beta signaling overcome senescence of mouse keratinocytes expressing v-Ha-ras.

Previous studies have shown that TGFbeta1 expression is upregulated in mouse keratinocytes infected with a v-rasHa retrovirus, although the functional significance of this has not been clear. Here we show that v-rasHa retrovirus transduced primary mouse keratinocytes undergo hyperproliferation followed by a TGFbeta1 dependent G1 growth arrest and senescence. The growth arrest is accompanied by a 15-fold increase in total TGFbeta1 secreted and a fourfold increase in secreted active TGFbeta1. When cultured in the presence of a neutralizing antibody to TGFbeta1, the senescence response is suppressed. Levels of the TGFbeta1 target p15ink4b increase during senescence as does association of this kinase inhibitor with cyclinD/cdk4 complexes. However, p16ink4a, p53 and p19ARF expression also increase during senescence. Genetic analysis shows that TGFbeta1 null and dominant negative TbetaBRII expressing v-rasHa keratinocytes resist the G1 growth arrest and do not senescence. This resistance is associated with low expression of p15ink4b and p16ink4a, constitutive Rb phosphorylation and high levels of cdk4 and cdk2 kinase activity. In contrast, inactivation of TGFbetabeta1 secretion or response does not block the induction of p53 and p19ARF, but the level of p21waf1, a p53 target gene, is reduced in cyclin D/cdk4 and cyclin E/cdk2 complexes. Thus, although multiple senescence pathways are activated in response to a ras oncogene, inactivation of TGFbeta1 secretion or response is sufficient to block the senescence program. Since v-rasHa transduced TGFbeta1-/- keratinocytes form squamous cell carcinomas following skin grafting, these results suggest that in mouse keratinocytes, defects in TGFbeta1 signaling accelerate malignant progression by overcoming oncogene induced replicative senescence.

Defects in transforming growth factor-beta signaling cooperate with a Ras oncogene to cause rapid aneuploidy and malignant transformation of mouse keratinocytes.

Genetic inactivation of the transforming growth factor-beta (TGF-beta) signaling pathway can accelerate tumor progression in the mouse epidermal model of multistage carcinogenesis. By using an in vitro model of keratinocyte transformation that parallels in vivo malignant conversion to squamous cell carcinoma, we show that v-ras(Ha) transduced primary TGF-beta1-/- keratinocytes and keratinocytes expressing a TGF-beta type II dominant-negative receptor transgene have significantly higher frequencies of spontaneous transformation than control genotypes. Malignant transformation in the TGF-beta1-/- keratinocytes is preceded by aneuploidy and accumulation of chromosomal aberrations. Similarly, transient inactivation of TGF-beta signaling with a type II dominant-negative receptor adenovirus causes rapid changes in ploidy. Exogenous TGF-beta1 can suppress aneuploidy, chromosome breaks, and malignant transformation of the TGF-beta1-/- keratinocytes at concentrations that do not significantly arrest cell proliferation. These results point to genomic instability as a mechanism by which defects in TGF-beta signaling could accelerate tumor progression in mouse multistage carcinogenesis.

Mice lacking Smad3 show accelerated wound healing and an impaired local inflammatory response.

The generation of animals lacking SMAD proteins, which transduce signals from transforming growth factor-beta (TGF-beta), has made it possible to explore the contribution of the SMAD proteins to TGF-beta activity in vivo. Here we report that, in contrast to predictions made on the basis of the ability of exogenous TGF-beta to improve wound healing, Smad3-null (Smad3ex8/ex8) mice paradoxically show accelerated cutaneous wound healing compared with wild-type mice, characterized by an increased rate of re-epithelialization and significantly reduced local infiltration of monocytes. Smad3ex8/ex8 keratinocytes show altered patterns of growth and migration, and Smad3ex8/ex8 monocytes exhibit a selectively blunted chemotactic response to TGF-beta. These data are, to our knowledge, the first to implicate Smad3 in specific pathways of tissue repair and in the modulation of keratinocyte and monocyte function in vivo.