Median raphe cysts: A clinico-pathologic and immunohistochemical study of 52 cases.

BACKGROUND: Median raphe cysts (MRC) are epithelial-lined cystic lesions of the genital area that do not communicate with the urethra or the overlying epidermis. Immunohistochemically, MRC show positivity for cytokeratin (CK) 5-6, CK 7, carcinoembryonic antigen, p63 and uroplakin III (URO III). GATA3 and human milk fat globulin 1 (HMFG1) are immunohistochemical markers that have been not previously studied in MRC. METHODS: We conducted a study of 52 patients diagnosed with MRC in the Pathology Departments of eight hospitals between 1990 and 2016. The monoclonal antibodies used were CK5-6, CK7, CK20, URO III, p63, GATA3, and HMFG1. HMFG1 was studied in five cases of apocrine hidrocystomas and compared with five cases of MRC from our series. RESULTS: CK 5-6, CK7, and p63 expression showed strong positivity in the urothelial epithelium of 48 cases. CK20 was focally positive in areas of mucinous differentiation in three cases. GATA3 showed intense nuclear staining in 30 cases. HMFG1 was positive in three cases of MRC and in three cases of apocrine hidrocystoma. CONCLUSION: Positivity of GATA3 and CK7 in MRC supports the urothelial origin of these cysts. We found no differences in HMFG1 expression between MRC and apocrine hidrocystomas.

A Skin Plaque Preceding Systemic Relapse of Gamma-Delta Hepatosplenic T-Cell Lymphoma.

Hepatosplenic T-cell lymphoma (HSTL) is an uncommon, aggressive peripheral T-cell lymphoma with a dismal prognosis, usually expressing gamma-delta T-cell receptor on immunohistochemical study. We report the second instance in the literature of a solitary skin nodule heralding recurrence of HSTL. The patient was a 40-year-old man in apparent remission from HSTL, 4 years after chemotherapy and autologous bone marrow transplant. Biopsy of a flank lesion showed atypical lymphoid cells involving the dermis with a perivascular and periadnexal pattern, and fat lobules of the subcutaneous tissue. Their phenotype mirrored that of previous biopsies, with expression of CD2, CD3, CD7, CD56, and T-cell receptor-gamma, and lack of T-cell receptor-beta, CD4, CD5, and CD8. Cutaneous involvement by HSTL has rarely been reported either at initial diagnosis or at recurrence, and represents a diagnostic pitfall for primary cutaneous gamma-delta T-cell lymphoma.

Mucinous Metaplasia of the Vulva in Zoon Vulvitis and Lichen Sclerosus et Atrophicus. Description of 3 Additional Cases of a Rarely Reported Histopathologic Finding.

Mucinous metaplasia of the vulva (MMV) is a histopathologic finding that has been reported previously in only 3 patients and needs to be distinguished from vulvar extramammary Paget disease. We report 3 additional instances of MMV associated to Zoon vulvitis and vulvar lichen sclerosus et atrophicus. Histochemical and immunohistochemical studies were performed on biopsies from erythematous and erosive vulvar lesions of 3 women aged 64, 80 and 84 years, with features of Zoon vulvitis (2 cases) and lichen sclerosus et atrophicus (1 case). Mucin-containing epithelial cells were present on the uppermost layers of the squamous epithelium. On immunohistochemical study the metaplastic cells were positive for cytokeratin 7, epithelial membrane antigen and carcinoembryonic antigen, thus mimicking the phenotype of Paget disease. MMV is most likely related to chronic inflammation. Cytological and architectural features allow for distinction from Paget disease because the mucin-containing cells of mucinous metaplasia of the vulva lack atypia and are predominantly located on the most superficial layers of the surface epithelium.

Role of heterotrimeric G protein and calcium in cardiomyocyte hypertrophy induced by IGF-1.

In the heart, insulin-like growth factor-1 (IGF-1) is a peptide with pro-hypertrophic and anti-apoptotic actions. The pro-hypertrophic properties of IGF-1 have been attributed to the extracellular regulated kinase (ERK) pathway. Recently, we reported that IGF-1 also increases intracellular Ca(2+) levels through a pertussis toxin (PTX)-sensitive G protein. Here we investigate whether this Ca(2+) signal is involved in IGF-1-induced cardiomyocyte hypertrophy. Our results show that the IGF-1-induced increase in Ca(2+) level is abolished by the IGF-1 receptor tyrosine kinase inhibitor AG538, PTX and the peptide inhibitor of Gßγ signaling, ßARKct. Increases in the activities of Ca(2+) -dependent enzymes calcineurin, calmodulin kinase II (CaMKII), and protein kinase Cα (PKCα) were observed at 5 min after IGF-1 exposure. AG538, PTX, ßARKct, and the dominant negative PKCα prevented the IGF-1-dependent phosphorylation of ERK1/2. Participation of calcineurin and CaMKII in ERK phosphorylation was discounted. IGF-1-induced cardiomyocyte hypertrophy, determined by cell size and ß-myosin heavy chain (ß-MHC), was prevented by AG538, PTX, ßARKct, dominant negative PKCα, and the MEK1/2 inhibitor PD98059. Inhibition of calcineurin with CAIN did not abolish IGF-1-induced cardiac hypertrophy. We conclude that IGF-1 induces hypertrophy in cultured cardiomyocytes by activation of the receptor tyrosine kinase activity/ßγ-subunits of a PTX-sensitive G protein/Ca(2+) /PKCα/ERK pathway without the participation of calcineurin.

Saurian papulosis: a new clinicopathological entity.

BACKGROUND: Epidermal keratinization disorders comprise a heterogeneous group of skin diseases that share the common feature of abnormal epidermal maturation, often leading to a disturbed stratum corneum. OBJECTIVE: To describe two cases of an unusual disorder of epidermal keratinization. METHODS: The clinical features of two unrelated patients with a long-standing widespread cutaneous eruption are described. Histopathologic examination and immunohistochemical studies were performed on skin biopsy specimens. RESULTS: The eruption was characterized by symmetric erythematous, flat, discrete papules with a polygonal shape and fine scaling. The papules covered most of the skin surface and, in some areas of the trunk, they were arranged along the lines of cleavage, parallel to the ribs. There was no facial, mucosal, nail, or palmoplantar involvement; the teeth and hair were normal. The first patient had a sister with an identical eruption, and a brother of the second patient was said to have similar skin lesions. Histopathology revealed well-demarcated areas of compact eosinophilic orthokeratotic hyperkeratosis overlying a slightly acanthotic epidermis. Lesional skin showed weaker immunoexpression for connexin 43 compared with normal skin. LIMITATIONS: Only two patients and one sibling were investigated. CONCLUSION: We propose the name "saurian papulosis" to describe this newly described clinicopathologic entity.

Elevated expression of MeCP2 in cardiac and skeletal tissues is detrimental for normal development.

MeCP2 plays a critical role in interpreting epigenetic signatures that command chromatin conformation and regulation of gene transcription. In spite of MeCP2's ubiquitous expression, its functions have always been considered in the context of brain physiology. In this study, we demonstrate that alterations of the normal pattern of expression of MeCP2 in cardiac and skeletal tissues are detrimental for normal development. Overexpression of MeCP2 in the mouse heart leads to embryonic lethality with cardiac septum hypertrophy and dysregulated expression of MeCP2 in skeletal tissue produces severe malformations. We further show that MeCP2's expression in the heart is developmentally regulated; further suggesting that it plays a key role in regulating transcriptional programs in non-neural tissues.

The transcription factor MEF2C mediates cardiomyocyte hypertrophy induced by IGF-1 signaling.

Myocyte enhancer factor 2C (MEF2C) plays an important role in cardiovascular development and is a key transcription factor for cardiac hypertrophy. Here, we describe MEF2C regulation by insulin-like growth factor-1 (IGF-1) and its role in IGF-1-induced cardiac hypertrophy. We found that IGF-1 addition to cultured rat cardiomyocytes activated MEF2C, as evidenced by its increased nuclear localization and DNA binding activity. IGF-1 stimulated MEF2 dependent-gene transcription in a time-dependent manner, as indicated by increased MEF2 promoter-driven reporter gene activity; IGF-1 also induced p38-MAPK phosphorylation, while an inhibitor of p38-MAPK decreased both effects. Additionally, inhibitors of phosphatidylinositol 3-kinase and calcineurin prevented IGF-1-induced MEF2 transcriptional activity. Via MEF2C-dependent signaling, IGF-1 also stimulated transcription of atrial natriuretic factor and skeletal alpha-actin but not of fos-lux reporter genes. These novel data suggest that MEF2C activation by IGF-1 mediates the pro-hypertrophic effects of IGF-1 on cardiac gene expression.

Music Therapy for Pain and Anxiety Management in Nasal Bone Fracture Reduction: Randomized Controlled Clinical Trial.

OBJECTIVE: To evaluate whether listening to music through binaural headphones contributes to the perception of pain and anxiety in patients undergoing closed nasal bone fracture reductions. STUDY DESIGN: Randomized controlled trial. SUBJECTS AND METHODS: We recruited patients from San Juan de Dios Hospital with displaced nasal fractures who required a reduction and assigned them to a control group or a music group. For both groups, a protocolized closed reduction of the nasal fracture with local anesthesia was performed. The music group heard music through headphones during the pre-, intra-, and postprocedural periods of the intervention. Physiological variables (blood pressure and heart rate) were measured. An anxiety survey (State-Trait Anxiety Inventory) and the visual analog scale for measuring pain were also applied. RESULTS: The music group exhibited significantly lower levels of systolic blood pressure (P = .0001), anxiety (P < .0001), and pain (P = .0004) than the control group. CONCLUSION: Listening to music through headphones-a safe and low-cost intervention-appears to aid in pain and anxiety management associated with procedures that are usually uncomfortable, such as the reduction of nasal bone fractures with local anesthesia. We believe that this effect is achieved by the modulation of pain and anxiety on an emotional-affective dimension at a central level. Given its safety, feasibility, and low cost, music therapy should be considered a complementary treatment for pain and anxiety management for nasal fracture reduction performed with local anesthesia, as well as for other medical procedures of similar pain levels conducted without general anesthesia.

Rotura del septum interventricular post infarto agudo al miocardio: una complicación potencialmente letal Revisión de la literatura a propósito de un caso clínico / Ventricular septal rupture after acute myocardial infarction: a potentially lethal complication Case report and literature review

Rupture of the ventricular septum with the appearance of an interventricular communication is an infrequent and life-threatening mechanical complication after acute myocardial infarction. The advent of coronary reperfusion therapies has reduced the incidence of this complication, but mortality remains high. The clinical presentation varies from mild compromise with exertional dyspnea to severe compromise with cardiogenic shock. In this pathology, early diagnosis is fundamental and surgical repair is the treatment of choice. In this article we report an interesting clinical case about a 77-year-old woman who was belatedly referred to our hospital and diagnosed with postinfarction rupture of the ventricular septum with an unfortunately fatal evolution. Relevance of this case lies in its atypical clinical presentation which led to a delay in diagnosis and a missed opportunity for early reperfusion therapy. An updated literature review about rupture of the ventricular septum complicating acute myocardial infarction was carried out.

[EFFECT OF EARLY PROTEIN-CALORIE MALNUTRITION ON NUTRITIONAL STATUS AND ATTRIBUTES OF THE METABOLIC SYNDROME IN YOUNG ADULTS]. / EFECTOS DE LA DESNUTRICIÓN CALÓRICO-PROTEICA TEMPRANA EN EL ESTADO NUTRICIONAL Y ATRIBUTOS DEL SÍNDROME METABÓLICO EN UNA COHORTE DE ADULTOS JÓVENES.

BACKGROUND: during recent years consistent studies have characterized the relationship between moderate and severe protein-calorie malnutrition and the appearance of non-communicable diseases in adulthood like metabolic syndrome (MS). AIM: to analyze the relationship between moderate and severe protein-calorie malnutrition during the first 1 000 days of life and the MS in a cohort of adults from Curicó, Chile. MATERIAL AND METHODS: we studied 49 young adults who had suffered moderate to severe protein-calorie malnutrition during their first two years of life. Anthropometry, blood pressure measurement and laboratory tests were performed, and the burden of MS attributes was determined. RESULTS: the prevalence of MS was 14.3% with no significant differences by gender, showing a direct and significant association between burden of MS and body mass index, waist / height index, blood pressure, plasma levels of glucose and triglyceride, and an inverse association with HDL. CONCLUSION: systolic blood pressure and plasma level of triglyceride represented the most important risk factors for SM in this cohort. We found no association between the presence of protein-calorie malnutrition and MS.

Introducción: estudios consistentes durante los últimos años han caracterizado la relación entre la desnutrición calórico-proteica (DCP) y el desarrollo de enfermedades no transmisibles en la adultez, como el Síndrome Metabólico (SM). Objetivo: analizar la relación entre SM en la adultez y la DCP durante los primeros 1.000 días de vida en una cohorte de adultos recientemente generada en Curicó, Chile. Material y métodos: se analizaron 49 sujetos adultos jóvenes que durante sus primeros dos años de vida sufrieron desnutrición calórico-proteica moderada a severa mediante la realización de antropometría, medición de la presión arterial y exámenes de laboratorio. Se determinó la prevalencia del SM y la carga de sus atributos. Resultados: se obtuvo una prevalencia de SM del 14,3% sin diferencias significativas por género, con una asociación directa y notable entre la carga de SM, el índice de masa corporal (IMC), el índice cintura/talla, presión arterial y niveles plasmáticos de glicemia y triglicéridos (TG), y una asociación inversa con colesterol HDL. Conclusión: la presión arterial sistólica y el valor plasmático de TG representaron los factores de riesgo más importantes del SM en esta cohorte. No se encontró asociación entre la DCP en los 1.000 primeros días de vida y el SM en la adultez.

Spironolactone decreases DOCA-salt-induced organ damage by blocking the activation of T helper 17 and the downregulation of regulatory T lymphocytes.

Adaptive immune response has been implicated in inflammation and fibrosis as a result of exposure to mineralocorticoids and a high-salt diet. We hypothesized that in mineralocorticoid-salt-induced hypertension, activation of the mineralocorticoid receptor alters the T-helper 17 lymphocyte (Th17)/regulatory T-lymphocyte/interleukin-17 (IL-17) pathway, contributing to cardiac and renal damage. We studied the inflammatory response and tissue damage in rats treated with deoxycorticosterone acetate and high-salt diet (DOCA-salt), with or without mineralocorticoid receptor inhibition by spironolactone. To determine whether Th17 differentiation in DOCA-salt rats is caused by hypertension per se, DOCA-salt rats received antihypertensive therapy. In addition, to evaluate the pathogenic role of IL-17 in hypertension and tissue damage, we studied the effect of IL-17 blockade with a specific antibody (anti-IL-17). We found activation of Th17 cells and downregulation of forkhead box P3 mRNA in peripheral tissues, heart, and kidneys of DOCA-salt-treated rats. Spironolactone treatment prevented Th17 cell activation and increased numbers of forkhead box P3-positive cells relative to DOCA-salt rats. Antihypertensive therapy did not ameliorate Th17 activation in rats. Treatment of DOCA-salt rats with anti-IL-17 significantly reduced arterial hypertension as well as expression of profibrotic and proinflammatory mediators and collagen deposits in the heart and kidney. We conclude that mineralocorticoid receptor activation alters the Th17/regulatory T-lymphocyte/IL-17 pathway in mineralocorticoid-dependent hypertension as part of an inflammatory mechanism contributing to fibrosis.

Mineralocorticoid receptor antagonism attenuates cardiac hypertrophy and prevents oxidative stress in uremic rats.

Chronic renal failure causes left ventricular hypertrophy, but the molecular mechanisms involved remain unknown. We, therefore, investigated whether the mineralocorticoid receptor is implicated in the cardiac hypertrophy observed in uremic rats and whether mineralocorticoid receptor blockade could be protective in chronic renal failure. Experimental groups were: control rats, uremic rats (NPX) with 5/6 nephrectomy (5 weeks), and NPX rats fed with spironolactone for 5 weeks. Systolic blood pressure was increased in both NPX rats and NPX rats fed with spironolactone for 5 weeks. Echocardiography revealed concentric left ventricular hypertrophy in uremia, which was attenuated by spironolactone. Enlarged cardiomyocyte size was observed in both left and right ventricles of NPX rats, an effect that was prevented by spironolactone. Mineralocorticoid receptor antagonism attenuated the increase of ventricular brain natriuretic peptide mRNA levels induced by nephrectomy. Left ventricular gene expressions of aldosterone synthase, mineralocorticoid receptor, and hydroxysteroid dehydrogenase type 2 were the same in the 3 groups, whereas gene expression of the glucocorticoid receptor was significantly diminished in chronic renal failure rats. No significant differences in cardiac aldosterone were observed between control rats and NPX rats, although NPX rats fed with spironolactone for 5 weeks showed increased plasma aldosterone levels. However, a significant increase in serum and glucocorticoid-inducible kinase-1 mRNA expression and protein was present in the NPX group; spironolactone treatment significantly reduced serum and glucocorticoid-inducible kinase-1 mRNA and protein in the left ventricle. Uremic rats exhibited a significant increase of superoxide production and reduced nicotinamide-adenine dinucleotide phosphate oxidase subunits expression (NOX-2, NOX-4, and p47(phox)) in the left ventricle, which was prevented by the mineralocorticoid receptor antagonist. Our findings provide evidence of the beneficial effects of spironolactone in cardiac hypertrophy and cardiac oxidative stress in chronic renal failure.

Interstitial granulomatous dermatitis with histiocytic pseudorosettes: a new histopathologic pattern in cutaneous borreliosis. Detection of Borrelia burgdorferi DNA sequences by a highly sensitive PCR-ELISA.

BACKGROUND: The cutaneous manifestations of Borrelia burgdorferi infection include an early phase of erythema chronicum migrans and a late stage of acrodermatitis chronica atrophicans lesions. OBJECTIVE: We describe 11 patients with peculiar cutaneous manifestations and distinctive histopathologic findings as the result of B burgdorferi infection. METHODS: Eleven patients with B burgdorferi detected by polymerase chain reaction or polymerase chain reaction enzyme-linked immunosorbent assay in their cutaneous lesions were included in this study. We analyzed clinical data and histopathologic findings in all patients. The inflammatory infiltrate was also immunohistochemically investigated. RESULTS: Most patients showed a peculiar clinical setting of morphea, and a few cases presented the characteristic appearance of erythema chronicum migrans instead of acrodermatitis chronica atrophicans, as would be expected in a late phase of B burgdorferi infection. The histopathologic findings were similar in all cases and consisted of an interstitial inflammatory infiltrate mostly composed of histiocytes dispersed among the collagen bundles of the dermis and focal areas of small pseudorosette formation, characterized by small histiocytes radially disposed around thick collagen bundles. In some cases there were also a few plasma cells intermingled with the histiocytes. CONCLUSION: Cutaneous lesions with clinical appearance similar to that of morphea and histopathologic features closely resembling those of the interstitial type of granuloma annular may be seen in intermediate-stage cutaneous lesions of B burgdorferi infection. These clinical and histopathologic findings represent a constellation of findings that have not been previously characterized as a cutaneous manifestation of B burgdorferi infection.

Acral arteriovenous tumor developed within a nevus flammeus in a patient with Sturge-Weber syndrome.

The Sturge-Weber syndrome consists of a large facial nevus flammeus in the distribution of the ophthalmologic division of the trigeminal nerve accompanied by ipsilateral leptomeningeal angiomatosis. Usually, when angiomatous nodules develop in a nevus flammeus of a patient with Sturge-Weber syndrome they are pyogenic granulomas. We describe an acral arteriovenous tumor developed within the nevus flammeus of a patient with Sturge-Weber syndrome. To our knowledge, acral arteriovenous tumor has not been previously described in the cutaneous vascular malformation of patients with Sturge-Weber syndrome. The development of acral arteriovenous tumor within the vascular malformation of a nevus flammeus in this patient with Sturge-Weber syndrome probably results from a vascular proliferation secondary to underlying arteriovenous shunts.

Chloracne: histopathologic findings in one case.

BACKGROUND: Chloracne is an acneiform eruption due to poisoning by halogenated aromatic compounds having a specific molecular shape. This condition is always a symptom of systemic poisoning by chemical chloracnegens and not just a cutaneous disorder. METHODS: We have studied a patient with severe chloracne who showed cutaneous lesions involving mostly the face and the axillae. RESULTS: Histopathologic study of the facial lesions demonstrated that almost every vellus hair follicle was involved, showing a dilated infundibulum filled by a keratotic plug. This keratotic material was mostly composed of orthokeratotic basket-weave basophilic corneocytes, namely infundibular keratin, although there were also some dilated infundibula containing eosinophilic laminated or granular sebum at their center. Small infundibular cysts were more numerous than comedones. Mature and well-developed sebaceous glands were seen at the base of many of the dilated infundibula and no squamous metaplasia of the sebaceous glands or ducts could be demonstrated. Hyperpigmentation of the lesions resulted from hyperproduction of melanin by a normal number of melanocytes along the basal layer of the epidermis and infundibular epithelium. Abundant melanin granules also impregnated the corneocytes of the infundibular plugs. CONCLUSIONS: Our findings support the notion that tiny infundibular cysts rather than comedones represent the basic lesions of chloracne.

Insulin-like growth factor-1 induces an inositol 1,4,5-trisphosphate-dependent increase in nuclear and cytosolic calcium in cultured rat cardiac myocytes.

In the heart, insulin-like growth factor-1 (IGF-1) is a pro-hypertrophic and anti-apoptotic peptide. In cultured rat cardiomyocytes, IGF-1 induced a fast and transient increase in Ca(2+)(i) levels apparent both in the nucleus and cytosol, releasing this ion from intracellular stores through an inositol 1,4,5-trisphosphate (IP(3))-dependent signaling pathway. Intracellular IP(3) levels increased after IGF-1 stimulation in both the presence and absence of extracellular Ca(2+). A different spatial distribution of IP(3) receptor isoforms in cardiomyocytes was found. Ryanodine did not prevent the IGF-1-induced increase of Ca(2+)(i) levels but inhibited the basal and spontaneous Ca(2+)(i) oscillations observed when cardiac myocytes were incubated in Ca(2+)-containing resting media. Spatial analysis of fluorescence images of IGF-1-stimulated cardiomyocytes incubated in Ca(2+)-containing resting media showed an early increase in Ca(2+)(i), initially localized in the nucleus. Calcium imaging suggested that part of the Ca(2+) released by stimulation with IGF-1 was initially contained in the perinuclear region. The IGF-1-induced increase on Ca(2+)(i) levels was prevented by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-AM, thapsigargin, xestospongin C, 2-aminoethoxy diphenyl borate, U-73122, pertussis toxin, and betaARKct (a peptide inhibitor of Gbetagamma signaling). Pertussis toxin also prevented the IGF-1-dependent IP(3) mass increase. Genistein treatment largely decreased the IGF-1-induced changes in both Ca(2+)(i) and IP(3). LY29402 (but not PD98059) also prevented the IGF-1-dependent Ca(2+)(i) increase. Both pertussis toxin and U73122 prevented the IGF-1-dependent induction of both ERKs and protein kinase B. We conclude that IGF-1 increases Ca(2+)(i) levels in cultured cardiac myocytes through a Gbetagamma subunit of a pertussis toxin-sensitive G protein-PI3K-phospholipase C signaling pathway that involves participation of IP(3).

IGF-1: un factor de crecimiento con acciones cardiovasculares pleiotrópicas / IGF-1: a growth factor with pleiotropic cardiovascular actions

El factor de crecimiento análogo a insulina tipo 1 (IGF-1) es un péptido relacionado estructural y funcionalmente con insulina que posee efectos mitogénicos y citoprotectores. Sus efectos biológicos dependen de la activación del receptor de IGF- 1 (IGF-1R), perteneciente a la familia de receptores con actividad tirosina kinasa intrínseca y que se localiza en la superficie celular. IGF-1 es el principal mediador fisiológico de la hormona del crecimiento y dado que su gen se expresa en múltiplestejidos, este factor es clave en la comunicación endocrina, paracrina y autocrina. Recientes evidencias muestran que IGF- 1 ejerce variadas acciones pleiotrópicas en el sistema cardiovascular, destacándose sus efectos en la hipertrofia, muerte y regeneración celular. En el corazón, IGF-1 promueve su crecimiento, mejora su contractibilidad, facilita el metabolismode la glucosa, disminuye el nivel de insulina circulante, aumenta la sensibilidad a esta hormona, estabiliza el perfil lipídico y estimula la regeneración del músculo cardíaco. Evidencias clínicas y experimentales han mostrado que el deterioro de la función cardíaca se asocia a bajos niveles circulantes de IGF-1. Alteraciones tanto en los niveles de IGF-1 como en su sistema transduccional se consideran factores de riesgo para el desarrollo de distintas patologías cardíacas. Todosestos antecedentes destacan el papel del IGF-1 en cardioprotección y su potencialidad para el tratamiento de diversas patologías cardiovasculares. Sin embargo, los mecanismos moleculares implicados en estos efectos prácticamente se desconocen. En esta revisión, junto con entregar antecedentes actualizados y críticos de las acciones cardiovasculares del IGF-1, se proyectan sus aplicaciones terapéuticas.

Sistemas de transducción de señales en la hipertrofia cardíaca / Signaling mechanisms in cardiac hypertrophy

Los cardiomiocitos son células terminalmente diferenciadas que cesan de dividirse inmediatamente después del nacimiento. Esto hace del corazón un órgano muy vulnerable a eventos isquémicos, tóxicos e inflamatorios. La sobrecarga hemodinámica induce hipertrofia cardíaca, produciendo un aumento de sarcómeros y del volumen celular. Aunque la hipertrofia es inicialmente beneficiosa, aumentando el gasto cardíaco, finalmente es deletérea, generando cardiomiopatía, insuficiencia cardíaca y muerte súbita. El estiramiento mecánico de los cardiomiocitos activa la expresión de genes hipertróficos y de factores de crecimiento cardíacos (agonistas adrenérgicos, Ang II, ET-1, IGF-1, CT-1, FGF-2, TGF-ß, hormonas tiroideas, TNF-alfa, LIF). Estos factores humorales activan diversas vías transduccionales responsables de la expresión de genes hipertróficos. Estas vías son: proteínas kinasas activadas por mitógenos (MAP kinasas), proteína kinasa C (PKC), proteína kinasa dependiente de calcio/calmodulina (CaMK) y calcineurina. Las MAPKs (ERK, JNK y p38-MAPK) se activan por fosforilación secuencial en cascada. La PKC se activa por receptores acoplados a la proteína Gq. Ambas vías se interrelacionan y controlan factores transcripcionales responsables de la hipertrofia. La calcineurina es una fosfatasa dependiente de CA2+ y CaM que desfosforila y activa a NFAT3. La CaMK activa a MEF2 al disociarlo de una desacetilasa de historia tipo II. MEF2 y NFAT3 son factores transcripcionales que controlan la expresión de genes hipertróficos. El uso combinado de la manipulación mecánica/quirúrgica, animales transgénicos, adenovirus modificados genéticamente e inhibidores químicos farmacológicos, han contribuido a dilucidar las vías transduccionales involucradas en el desarrollo de la hipertrofia cardíaca. Sin embargo, recién se están empezando a vislumbrar los mecanismos por los cuales las distintas vías conversan entre sí. Sólo entendiendo la compleja interrelación de las múltiples vías transduccionales se podrán diseñar fármacos que permitan controlar el proceso hipertrófico