Treatment response in the PIVENS trial is associated with decreased Hedgehog pathway activity.

UNLABELLED: Hedgehog (Hh) ligand production by ballooned hepatocytes drives nonalcoholic steatohepatitis (NASH) progression in mice. The NIDDK-sponsored PIVENS trial (NCT00063622) showed that vitamin E (VitE) improved NASH. We investigated whether VitE treatment and improvement in NASH were associated with changes in Hh pathway activity. Immunohistochemistry (IHC) was performed on both pre- and posttreatment liver biopsies of 59 PIVENS patients randomized to VitE (n = 30) or placebo (n = 29). Sonic Hh (Shh) ligand-producing cells and Shh-responsive cells were quantified. The latter was accomplished by triple IHC for gli2+ (marker of Hh signaling), sox-9 (progenitor marker), and α-smooth muscle actin (α-SMA; myofibroblast marker). Ballooned hepatocytes were quantified by keratin 8/18 and ubiquitin (K8/18/Ub) staining. IHC results were correlated with primary clinical and histologic PIVENS data. Pretreatment clinical, histologic, and IHC parameters did not differ significantly in the two treatment groups. Regardless of treatment arm, the number of Shh+ hepatocytes correlated with K8/18/Ub foci (r(2) = 0.47, P < 0.001) and aspartate aminotransferase (AST) (r(2) = 0.15, P = 0.002). Treatment-related changes in the numbers of Shh+ hepatocytes correlated with changes in serum AST (partial r(2) = 0.75, P < 0.0001), hepatocyte ballooning (P = 0.004), the ductular reaction (i.e., numbers of gli2+/sox9+ cells; P = 0.03 and α-SMA+ cells; P = 0.10), and fibrosis stage (P = 0.02). Treatment response was associated with a greater decrease in Shh+ hepatocytes than nonresponse (P = 0.007). The VitE group demonstrated a greater reduction in K8/18/Ub+ foci (P < 0.08) and Shh+ hepatocytes (P < 0.05) than the placebo group, effects that became more significant after correction for baseline differences and multiple linear regression analysis. CONCLUSION: During PIVENS, treatment response correlated with loss of Shh+ hepatocytes and improvement in Hh-regulated processes that promote NASH progression.

Scleroderma and IgG4-related disease.

IgG4-related disease is a syndrome which involves lymphoplasmacytic infiltrates and soft tissue sclerosis, elevated serum IgG4 titer, and increased IgG4-positive plasma cells in a variety of tissues. Scleroderma is also characterized by fibrosis and lymphoplasmacytic infiltrates. To our knowledge, the presence of IgG4-positive cells has not been well characterized in scleroderma. A retrospective review of scleroderma and related disorders (calcinosis, raynaud's syndrome, esophageal dysmotility, sclerodactyly, telangiectasia (CREST) syndrome, progressive systemic sclerosis, morphea) was performed. Thirty-four cases of scleroderma and related disorders were identified; IgG4-positive and IgG-positive plasma cells were counted in 10 HPF and an IgG4:IgG ratio determined. A cutoff ratio of 0.3 was used to define significant elevation. Three of the scleroderma cases had IgG4:IgG greater than 0. Only 1 case had a significant elevation. Of the 3 cases with elevated ratio, IgG4-positive cells ranged from 2 to 64 (median = 14), with an IgG4:IgG ranging from 0.06 to 0.34 (median = 0.22). Similar results were produced with the other sclerosing disorders. These results suggest that scleroderma is not part of the IgG4-related disease spectrum.

Increased production of sonic hedgehog by ballooned hepatocytes.

Ballooned hepatocytes distinguish non-alcoholic steatohepatitis (NASH) from steatosis. Such cells contain dilated endoplasmic reticulum and ubiquitin aggregates, characteristics of endoplasmic reticulum stress. Hepatocyte ballooning increases the risk for fibrosis in NASH, suggesting that ballooned hepatocytes release pro-fibrogenic factors. Hedgehog ligands function as pro-fibrogenic factors in liver diseases, but mechanisms for hedgehog ligand production remain poorly understood. We evaluated the hypothesis that endoplasmic reticulum stress induces hepatocyte production of hedgehog ligands that provide paracrine pro-fibrogenic signals to neighbouring cells. In livers from NASH patients, keratin 8/18 and ubiquitin staining demonstrated enlarged, keratin 8/18-negative/ubiquitin-positive hepatocytes (ballooned hepatocytes) that were positive for Sonic hedgehog. In order to model endoplasmic reticulum stress in vitro, primary mouse hepatocytes were treated with tunicamycin. Compared to vehicle, tunicamycin significantly increased Sonic hedgehog and Indian hedgehog expression. Furthermore, conditioned medium from tunicamycin-treated hepatocytes increased Gli-luciferase reporter activity 14-fold more than conditioned medium from vehicle-treated hepatocytes. Cyclopamine (hedgehog signalling inhibitor) abrogated the effect of conditioned medium from tunicamycin-treated hepatocytes, verifying that soluble hepatocyte-derived factors activate hedgehog signalling. Ballooned hepatocytes in NASH patients did not express the hedgehog target gene, Gli2, α-smooth muscle actin or vimentin, but were surrounded by Gli2-positive stromal cells expressing these myofibroblast markers. Trichrome staining demonstrated the accumulation of ballooned hepatocytes in areas of matrix deposition, and numbers of Sonic hedgehog-positive hepatocytes correlated with the degree of ballooning and fibrosis stage. Hepatocytes undergoing endoplasmic reticiulum stress generate hedgehog ligands which act as paracrine pro-fibrogenic factors for hedgehog-responsive stromal cells. These results help to explain why fibrosis stage correlates with hepatocyte ballooning in NASH.

Sarcomatoid mesothelioma: a clinical-pathologic correlation of 326 cases.

Sarcomatoid mesothelioma is the least common, but most aggressive of the three major histological types of mesotheliomas. This study comprises 326 cases of sarcomatoid mesotheliomas among 2000 consecutive malignant mesothelioma cases received in consultation (16%). Patients included 312 men (96%) and 14 women (4%), with a median age of 70 years (range 41-94 years). Most tumors were pleural (319; 98%), and 7 were peritoneal (2%). Some desmoplastic features were identified in 110 cases (34%), and 70 (21%) were classified as desmoplastic. Rare subtypes included two cases with a lymphohistiocytoid pattern (<1%) and eight heterologous mesotheliomas (2%). Labeling for cytokeratins (CKs) was observed in 261/280 cases (93%), and for calretinin and vimentin in 31 and 91%, respectively. Pleural plaques were present in 79% of cases for which information was available, and asbestosis was diagnosed in 34/127 cases (27%). Median survival was 3.5 months. Fiber analysis was performed in 61 cases. The median asbestos body count was 1640/g wet lung tissue (by light microscopy). Amosite fibers were the most commonly identified fibers using energy-dispersive X-ray analysis and were significantly higher in the sarcomatoid cases, as were uncoated fibers using scanning electron microscopy. This study represents the largest series of sarcomatoid and desmoplastic malignant mesotheliomas to date and confirms the diagnostic usefulness of CK immunohistochemistry. The relationship with asbestos exposure--particularly amosite--and an association with pleural plaques and less often asbestosis is confirmed.

Acquired vulvar lymphangioma circumscriptum: a comparison of 12 cases with Crohn's associated lesions or radiation therapy induced tumors.

BACKGROUND: Lymphangioma circumscriptum (LC) is a benign lesion of lymphatic origin. Vulvar involvement occurs in various clinical settings. METHODS: We present 12 cases, and compare lesions in patients with Crohn's disease and those associated with pelvic radiation. RESULTS: The average age at presentation was 49 years. Thirty-three percent of the patients had Crohn's disease, 58% had radiation therapy and 9% had no significant medical history. Sixty-seven percent of the patients had multifocal lesions in anatomically distinct regions. Patients presented on average 16 years after onset of predisposing factors. Presenting complaints were pruritus, wetness and vulvar edema. Lesions were clinically heterogeneous, often found on the labia majora. Lesions consisted of dilated lymphatic channels at the junction of the reticular and papillary dermis. The cells lining these spaces lacked cytologic atypicality or mitotic activity. All lesions so examined were immunoreactive for D240. Patients were most often treated with surgical excision followed by laser ablation. Four of twelve patients, all with radiation-associated lesions, experienced disease progression necessitating additional surgery. CONCLUSIONS: Patients with LC secondary to radiation, when compared to those with Crohn's disease, were 10 years younger, more likely to have associated co-morbidities, and frequently experienced disease progression needing additional surgeries. Acquired vulvar LC has multiple causes with differing prognosis.

Use of 111in-capromab pendetide immunoscintigraphy to image localized prostate cancer foci within the prostate gland.

PURPOSE: We compared the results of a preoperative (111)In-capromab pendetide scan co-registered with computerized tomography with pathological findings in the surgically excised prostate to determine whether the scan can efficiently detect cancer in the prostate. MATERIALS AND METHODS: This prospective trial included 25 hormone naïve men with clinically localized prostate cancer who underwent (111)In-capromab pendetide single photon emission computerized tomography/computerized tomography as part of the preoperative evaluation. In addition to routine histological analysis, representative prostate sections were stained for prostate specific membrane antigen using the same antibody used in the scan. A pathologist and a radiologist were blinded to pathology and imaging findings, respectively. Prostate specific membrane antigen immunohistochemistry was correlated with the 3-dimensional location of the prostate specific membrane antigen signal detected by scan. RESULTS: Scan sensitivity was 37% to 87% for 4 quadrants (right vs left and apical vs basal) with 0% to 50% specificity, as validated by final pathological assessment of the same quadrants. Stratifying positive scan signal strength did not statistically improve specificity (p = 0.35). There was no significant correlation between prostate specific membrane antigen over expression and tumor stage distribution (p = 0.23). CONCLUSIONS: The scan did not localize prostate cancer to a particular quadrant based on comparison with radical prostatectomy specimen pathology. The antibody used has affinity for benign and malignant prostatic glands in excised, formalin fixed prostate tissue, which may contribute to low scan specificity in vivo. The scan cannot be used to reliably detect or image cancer foci in the prostate.

The cutaneous manifestations of atypical complete DiGeorge syndrome: a histopathologic and immunohistochemical study.

DiGeorge syndrome is a congenital anomaly with a constellation of findings that includes thymic hypoplasia. Only a small subset of patients with DiGeorge syndrome has complete athymia, classified as complete DiGeorge anomaly; one third of these patients show an eczematous dermatitis, oligoclonal T-cells and lymphadenopathy, known as atypical complete DiGeorge anomaly. Six biopsies from six patients with the distinctive clinical phenotype of atypical complete DiGeorge anomaly were studied. Every biopsy showed exocytosis (100%), parakeratosis, often confluent and spongiosis (100%). Neutrophilic abscesses (50%), dyskeratosis (67%) and satellite cell necrosis (50%) were seen. Perieccrine and perivascular inflammation were seen in half of the cases. Eosinophils were identified (83%); most commonly in both the epidermis and dermis. All of lymphocytes were CD3 positive. Most (83%) of cases contained T-cell intracellular antigen 1 (TIA-1) positive cells. Special testing of the selected patients using spectratyping identified oligoclonal T-cell populations. The presence of dyskeratotic keratinocytes, satellite cell necrosis and parakeratotic scale with neutrophils characterizes the cutaneous rash seen in this subset of complete DiGeorge syndrome patients. Such skin lesions from patients with DiGeorge anomaly should alert the pathologist to the potential diagnosis of atypical complete DiGeorge anomaly. The pathophysiologic role of the oligoclonal T-cells in this entity requires additional study.

Expression of cadherin/catenin cell--cell adhesion molecules in a onychomatricoma.

Onychomatricoma is a rare nail tumor with a distinctive architecture. Proximally, there are serum-filled invaginations of nail matrix epithelium into the stroma, and distally, dermal protrusions perforate the nail plate. Because other matrical tumors of follicular and odontogenic origin express nuclear beta-catenin, we examined the expression of cadherin/catenin proteins in this onychomatricoma case. The patient presented with a toenail yellow streak, and the biopsy revealed an onychomatricoma. E-cadherin and beta-catenin were at the cell membrane in the epithelial invaginations. P-cadherin was restricted to basal cells. In contrast to other matrical tumors, nuclear beta-catenin was not present. These results suggest that onychomatricoma may lack the transcriptional activating role of beta-catenin that characterizes follicular and odontogenic matrical tumors. This is the first report on the expression of cadherin/ catenin cell-cell adhesion proteins in this rare nail tumor.

Differential expression of N-cadherin distinguishes a subset of metastasizing desmoplastic melanomas.

Desmoplastic melanoma is a variant of spindle cell melanoma considered at low risk for distant metastases when compared with other forms of melanoma. The emphasis in the differential diagnosis of desmoplastic melanomas has been placed mostly in distinguishing it from scars and other benign spindle cell proliferations. In contrast, recognizing a subset of desmoplastic melanomas with higher metastatic potential has proven more difficult. We studied the expression of N-cadherin in 21 desmoplastic melanomas. The expression of N-cadherin was examined by immunohistochemistry using archive material and a mouse anti-N-cadherin monoclonal antibody previously shown to react in routinely processed paraffin-embedded tissues. Of 21 cases, N-cadherin was strongly positive in 10, only weakly or focally positive in 3, and negative in 8. Seven of 21 patients had distant metastases, and N-cadherin was strongly positive in 6 of those 7 cases. In contrast, only 1 of 11 patients within the group of N-cadherin-negative or weakly positive tumors had distant metastases. Our results show that strong N-cadherin expression in desmoplastic melanoma correlates with distant metastases and potentially more aggressive behavior. In contrast, desmoplastic melanomas with low metastatic potential are mostly negative or only focally positive for N-cadherin. The data suggest that N-cadherin may be a useful marker in recognizing a subset of desmoplastic melanoma with higher metastatic potential.

Anterior rectal wall gastrointestinal stromal tumor presenting clinically as prostatic mass.

Gastrointestinal stromal tumors (GIST) of the anterior rectal wall can present as a prostatic mass, with concomitant obstructive symptoms. Transrectal biopsies of GIST may be misdiagnosed as primary prostatic sarcomas. We report 3 cases of GIST that were initially characterized as prostatic leiomyosarcomas and treated definitively with pelvic exenteration. The correct diagnosis was possible only after immunohistochemical staining for CD117 and was made retrospectively in 2 of 3 cases. Additional therapy with imatinib (Gleevec, Novartis Pharmaceuticals Corporation, East Hanover, NJ), an inhibitor of CD117 tyrosine kinase activity, treated recurrence in one patient and effected complete remission.

Pathology of parainfluenza virus infection in patients with congenital immunodeficiency syndromes.

Infection with parainfluenza virus typically produces a mild, self-limited upper respiratory infection. However, parainfluenza infections have become increasingly recognized as a source of severe morbidity and mortality in immunocompromised patients. In this retrospective study we identified 6 patients with congenital immunodeficiency and positive respiratory cultures for parainfluenza virus who died and underwent complete autopsy. Tissues obtained at autopsy were studied using hematoxylin and eosin-stained sections, immunoperoxidase staining for parainfluenza virus, and in selected cases, electron microscopy. All 6 patients exhibited typical cytopathic effects of parainfluenza virus, including giant cell formation, in lung and/or bronchial tissues. Parainfluenza virus infection was also documented by giant cell formation and immunohistochemistry in the pancreas (in 3 of 6 patients) and the kidney or bladder (in 2 of 4 patients). Anti-parainfluenza antibody also specifically reacted with cells in the gastrointestinal tract (in 2 of 4), spleen (in 4 of 6), thymus and/or lymph nodes (in 4 of 4), and small blood vessels in various organs (in 4 of 6). Pancreatic, bladder, colon, and thymic epithelial cell lines were susceptible to experimental infections with clinical isolates of parainfluenza virus type 3 in vitro. Parainfluenza virus infection was serious in patients with congenital immunodeficiencies, contributing directly to death in 5 of the 6 patients studied. Because this virus is capable of infecting tissues in the gastrointestinal and urinary systems as well as in the respiratory tract, body secretions and fluids from each of these locations should be considered potentially infectious.

Fatal disseminated adenovirus infections in immunocompromised patients.

Adenovirus has emerged as an important pathogen in immunocompromised patients, in whom disseminated disease occurs frequently and is associated with a high mortality rate. In a retrospective review of 1,847 consecutive autopsies, we identified 84 cases where adenovirus infection was suspected clinically. Adenovirus infection was confirmed at autopsy in 8 (10%) of 84 cases; all were immunocompromised patients. Six (75%) of these cases had disseminated adenovirus infection that contributed to death. Pathologic findings attributed to adenovirus infection included pneumonia with or without intra-alveolar hemorrhage, hepatic necrosis, enterocolitis with or without mucosal hemorrhage, epicardial hemorrhage, and ulcerations of the larynx, trachea, and ileum. This work shows that severe and fatal adenovirus infections are not infrequent, particularly in the immunocompromised population. Both clinicians and pathologists must become aware of the pathogenicity of adenovirus in this patient population, including its potential for causing life-threatening hemorrhage.

p40 (ΔNp63) and keratin 34ßE12 provide greater diagnostic accuracy than p63 in the evaluation of small cell lung carcinoma in small biopsy samples.

The use of p63 has been advocated for separating small cell lung carcinoma from poorly differentiated non-small cell lung carcinoma, in particular, squamous cell lung carcinoma. However, p63 is not entirely specific in this distinction, as several studies have demonstrated p63 immunoreactivity in a proportion of small cell lung carcinomas. p40 (ΔNp63) has recently been purported to be a highly specific marker for squamous cell lung carcinoma, but data regarding p40 (ΔNp63) in small cell lung carcinoma, a key differential diagnostic consideration in biopsy samples of squamous cell lung carcinoma, are lacking. In this study, a total of 34 previously confirmed small cell lung carcinomas (27 bronchoscopic biopsy samples and 7 large specimens) were immunostained for p40 (ΔNp63), p63, and keratin 34ßE12. All 34 small cell lung carcinomas were negative for p40 (ΔNp63) and keratin 34ßE12. Although none of the large small cell lung carcinoma specimens exhibited p63 immunoreactivity, 12 (44.4%) of 27 biopsy samples of small cell lung carcinoma were positive for p63. The rate of p63 staining in small cell lung carcinoma biopsy samples differed significantly from that of p40 (ΔNp63) and keratin 34ßE12 (P = .005). Ten cases of squamous cell lung carcinoma were also tested, all of which were positive for all 3 markers. These findings confirm that p63 immunoexpression is not uncommon in biopsy samples of small cell lung carcinoma. Positive p63 staining may be mistakenly interpreted as supportive of squamous differentiation and result in misclassification of small cell lung carcinoma as squamous cell lung carcinoma, a diagnostic error that has important therapeutic and prognostic consequences. To provide greater diagnostic accuracy, p40 (ΔNp63) or keratin 34ßE12 should be used instead of p63 in the distinction of small cell lung carcinoma from non-small cell lung carcinoma in biopsy samples.

Costaining for keratins 8/18 plus ubiquitin improves detection of hepatocyte injury in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease is a global health dilemma. The gold standard for diagnosis is liver biopsy. Ballooned hepatocytes are histologic manifestations of hepatocellular injury and are characteristic of steatohepatitis, the more severe form of nonalcoholic fatty liver disease. Definitive histologic identification of ballooned hepatocytes on routine stains, however, can be difficult. Immunohistochemical evidence for loss of the normal hepatocytic keratin 8/18 can serve as an objective marker of ballooned hepatocytes. We sought to explore the utility of a keratin 8/18 plus ubiquitin double immunohistochemical stain for the histologic evaluation of adult nonalcoholic fatty liver disease. Double immunohistochemical staining for keratin 8/18 and ubiquitin was analyzed using 40 adult human nonalcoholic fatty liver disease core liver biopsies. Ballooned hepatocytes lack keratin 8/18 staining as previously shown by others, but normal-size hepatocytes with keratin loss are approximately 5 times greater in number than keratin-negative ballooned hepatocytes. Keratin-negative ballooned hepatocytes, normal-size hepatocytes with keratin loss, and ubiquitin deposits show a zonal distribution, are positively associated with each other, and are frequently found adjacent to or intermixed with fibrous matrix. All 3 lesions correlate with fibrosis stage and the hematoxylin and eosin diagnosis of steatohepatitis (all P < .05). Compared with hematoxylin and eosin staining, immunohistochemical staining improves the receiver operating characteristics curve for advanced fibrosis (0.77 versus 0.83, 0.89, and 0.89 for keratin-negative ballooned hepatocytes, normal-size hepatocytes with keratin loss, and ubiquitin, respectively) because immunohistochemistry is more sensitive and specific for fibrogenic hepatocellular injury than hematoxylin and eosin staining. Keratin 8/18 plus ubiquitin double immunohistochemical stain improves detection of hepatocyte injury in nonalcoholic fatty liver disease. Thus, it may help differentiate nonalcoholic steatohepatitis from nonalcoholic fatty liver.

Changes in oligosaccharide chains of autoantibodies to GRP78 expressed during progression of malignant melanoma stimulate melanoma cell growth and survival.

A correlation between expression of the glucose-regulated protein of 78 kDa (GRP78) in malignant melanoma tumors and poor patient survival is well established. In this study, in addition to demonstrating the expression of GRP78 in tumor tissue, we investigated the immune response against GRP78 in a group of patients with different progression stages of malignant melanoma. Furthermore, we analyzed the glycosylation status of GRP78 immunoglobulin (Ig) G autoantibodies at these stages and evaluated their capacities to affect the protein B-dependent protein kinase signaling pathway and unfolded protein response signaling mechanisms, all known to promote malignant melanoma cell proliferation and survival. We found that progression of disease correlates not only with enhanced expression of GRP78 in the tumor but also with an increase in GRP78 autoantibody serum titers in these patients. We also found that the glycosylation status of anti-GRP78 IgG changes as the disease progresses. The anti-GRP78 IgG is abnormally glycosylated in the Fc region and asymmetrically glycosylated in the Fab region. We demonstrate that hyperglycosylated anti-GRP78 IgGs stimulate cell proliferation through protein B-dependent protein kinase signaling pathways. They also mimic the effects of α2-macroglobulin on the upregulation of GRP78 and X-box binding protein 1, activating transcription factor 6 α, and serine/threonine-protein kinase/endoribonuclease precursor α as endoplasmic reticulum stress biomarkers and show no effect on expression or activation of caspases 3, 9, or 12. In conclusion, the anti-GRP78 IgG autoantibodies downregulate apoptosis and activate unfolded protein response mechanisms, which are essential to promote melanoma cell growth and survival.

Cell-cell adhesion proteins in melanocytic pilomatrix carcinoma.

Tumors of the matrix of rigid structures include matrical tumors of the hairs, nails, and teeth. These tumors share similar phenotypical and signaling features. Although benign matrical hair tumors are among the most common of these tumors, hair matrix tumors containing pigmented melanocytes are very rare. The malignant variant called melanocytic pilomatrix carcinoma contains benign colonizing dendritic melanocytes admixed with the carcinomatous follicular matrical cells.We studied the expression of cadherins and ß-catenin in melanocytic pilomatrix carcinoma because cadherin/catenin-dependent cell-cell adhesion and signals play a critical role in the development of hair and hair tumors. We examined the expression of E- and P-cadherin and the multifunctional protein ß-catenin in two cases of melanocytic pilomatrix carcinoma by immunohistochemistry. E- and P-cadherin are expressed at the cell membrane. In contrast, ß-catenin is distributed uniformly in the nucleus and cytoplasm of all tumor cells. The diffuse nuclear and cytoplasmic ß-catenin expression found in melanocytic pilomatrix carcinomas is indicative of transcriptional activation and ß-catenin-induced cell transformation.This is the first report of cadherin/catenin expression in melanocytic pilomatrix carcinoma. Although the study is limited by the number of these rare tumors, the data add information for the understanding of disease mechanisms in hair matrical tumors. Matrical tumors of the hairs share phenotypical features with other matrical tumors and show nuclear translocation of ß-catenin, suggesting a transcriptional activating rather than a cellcell adhesion function.

A role for angiotensin II type 1 receptors on bone marrow-derived cells in the pathogenesis of angiotensin II-dependent hypertension.

Activation of type 1 angiotensin (AT(1)) receptors causes hypertension, leading to progressive kidney injury. AT(1) receptors are expressed on immune cells, and previous studies have identified a role for immune cells in angiotensin II-dependent hypertension. We, therefore, examined the role of AT(1) receptors on immune cells in the pathogenesis of hypertension by generating bone marrow chimeras with wild-type donors or donors lacking AT(1A) receptors (BMKO). The 2 groups had virtually identical blood pressures at baseline, suggesting that AT(1) receptors on immune cells do not make a unique contribution to the determination of baseline blood pressure. By contrast, in response to chronic angiotensin II infusion, the BMKOs had an augmented hypertensive response, suggesting a protective effect of AT(1) receptors on immune cells with respect to blood pressure elevation. The BMKOs had 50% more albuminuria after 4 weeks of angiotensin II-dependent hypertension. Angiotensin II-induced pathological injury to the kidney was similar in the experimental groups. However, there was exaggerated renal expression of the macrophage chemokine monocyte chemoattractant protein 1 in the BMKO group, leading to persistent accumulation of macrophages in the kidney. This enhanced mononuclear cell infiltration into the BMKO kidneys was associated with exaggerated renal expression of the vasoactive mediators interleukin-1beta and interleukin-6. Thus, in angiotensin II-induced hypertension, bone marrow-derived AT(1) receptors limited mononuclear cell accumulation in the kidney and mitigated the chronic hypertensive response, possibly through the regulation of vasoactive cytokines.

Stimulation of lymphocyte responses by angiotensin II promotes kidney injury in hypertension.

Activation of the renin-angiotensin system contributes to the progression of chronic kidney disease. Based on the known cellular effects of ANG II to promote inflammation, we posited that stimulation of lymphocyte responses by ANG II might contribute to the pathogenesis of hypertensive kidney injury. We therefore examined the effects of the immunosuppressive agent mycophenolate mofetil (MMF) on the course of hypertension and kidney disease induced by chronic infusion of ANG II in 129/SvEv mice. Although it had no effect on the severity of hypertension or cardiac hypertrophy, treatment with MMF significantly reduced albuminuria and ameliorated kidney injury, decreasing glomerulosclerosis and reducing lymphocyte infiltration into the renal interstitium. Attenuation of renal pathology with MMF was associated with reduced expression of mRNAs for the proinflammatory cytokines interferon-gamma and tumor necrosis factor-alpha and the profibrotic cytokine transforming growth factor-beta. As infiltration of the kidney by T lymphocytes was a prominent feature of ANG II-dependent renal injury, we carried out experiments examining the effects of ANG II on lymphocytes in vitro. We find that exposure of splenic lymphocytes to ANG II causes prominent rearrangements of the actin cytoskeleton. These actions require the activity of Rho kinase. Thus, ANG II exaggerates hypertensive kidney injury by stimulating lymphocyte responses. These proinflammatory actions of ANG II seem to have a proclivity for inducing kidney injury while having negligible actions in the pathogenesis of cardiac hypertrophy.

Cell adhesion protein expression in melanocytic matricoma.

Melanocytic matricoma is a rare neoplasm thought to recapitulate the hair follicle in anagen. The tumor forms a nodule in the dermis containing basaloid, intermediate and shadow cells admixed with pigmented melanocytes dispersed as single dendritic cells. Because cadherins and catenins are crucial in the development of hair tumors, we examined the expression of E(epithelial)-, P(placental)-, N(nerve)-cadherin and beta-catenin in a melanocytic matricoma. A 66-year-old Caucasian woman with a history of breast cancer presented with a pigmented nodule on the shoulder. Pathology revealed a melanocytic matricoma with S-100 and HMB45-positive melanocytes. E- and P-cadherin were localized at the cell membrane of basaloid and differentiating keratinocytes, and in melanocytes, recapitulating the anagen hair. Both cadherins were absent in shadow cells. N-cadherin was not expressed. Beta-catenin had a differential distribution, in the nucleus and cytoplasm of basaloid cells, but at the cell membrane in differentiating cells and negative in shadow cells, paralleling the expression of E- and P-cadherin. Our results support the previously hypothesized resemblance of the tumor to the hair bulb in anagen and suggest a transcriptional role of beta-catenin in the development of this rare neoplasm.