A primary tumour of the oesophagus with both melanocytic and schwannian differentiation. Melanocytic schwannoma or malignant melanoma?

A 76 year old white woman presented with a four month history of dysphagia and weight loss. Clinical, radiological, and endoscopic examination revealed a pigmented mass in the lower third of the oesophagus. The preoperative diagnosis, including biopsy examination, was that of malignant melanoma. Following oesophageal resection, the mass was found to be a localised, relatively superficial tumour with light, electron microscopic, and immunohistochemical features common to both Schwann cells and melanocytes. The patient survived 46 months after surgery and died of a stroke, with no evidence of tumour recurrence. The tumour is presented as a case of melanocytic schwannoma, with unique features when compared with oesophageal melanotic schwannomas and malignant melanomas described in the literature. The differential diagnosis is discussed and an origin from a common precursor cell of neural crest origin is postulated.     

Assessment of bone marrow stem cell reserve and function and stromal cell function in patients with severe congenital neutropenia

OBJECTIVE: To investigate further the cellular defect responsible for impaired granulopoiesis in severe congenital neutropenia (SCN), we have evaluated bone marrow (BM) stem cell reserve and function and BM stromal cell myelopoiesis supporting capacity in two patients with SCN. METHODS: BM primitive stem cells and myeloid progenitor cells were assessed using flow cytometry, limiting dilution assay, clonogenic assays, and long-term BM cultures (LTBMC). BM stroma function was assessed by evaluating the ability of irradiated stromal layers from the patients to induce granulocyte-macrophage colony formation (CFU-GM) by normal CD34+ cells. RESULTS: Compared to the normal controls (n = 37), SCN patients displayed a low percentage of CD34+/CD38+ cells (P < 0.05), low CFU-GM colony formation by highly purified CD34+ cells (P < 0.05), low CFU-GM recovery in LTBMC (P < 0.05), and normal primitive stem cells as indicated by the frequency of CD34+/CD38- cells and the number of long-term culture initiating cells. Patient BM stromal layers exhibited normal myelopoiesis supporting capacity as shown by the CFU-GM content of irradiated LTBMC recharged with normal CD34+ cells. In addition, patient LTBMC supernatants displayed 20-fold normal granulocyte colony stimulating factor and 2-fold normal granulocyte-macrophage colony stimulating factor levels. CONCLUSION: These data show that primitive BM stem cells and stromal cells are not affected in SCN patients, while they support further the concept of a primary defect at the myeloid progenitor cell level. To know the differentiation stage at which the underlying defect causes the malfunction will be relevant for further elucidation of its nature at the molecular level.     

Normal bone marrow hematopoietic stem cell reserves and normal stromal cell function support the use of autologous stem cell transplantation in patients with multiple sclerosis

Bone marrow (BM) stem cell reserves and function and stromal cell hematopoiesis supporting capacity were evaluated in 15 patients with multiple sclerosis (MS) and 61 normal controls using flow cytometry, clonogenic assays, long-term BM cultures (LTBMCs) and enzyme-linked immunosorbent assays. MS patients displayed normal CD34+ cell numbers but a low frequency of colony-forming cells (CFCs) in both BM mononuclear and purified CD34+ cell fractions, compared to controls. Patients had increased proportions of activated BM CD3+/HLA-DR+ and CD3+/CD38+ T cells that correlated inversely with CFC numbers. Patient BM CD3+ T cells inhibited colony formation by normal CD34+ cells and patient CFC numbers increased significantly following immunomagnetic removal of T cells from BMMCs, suggesting that activated T cells may be involved in the defective clonogenic potential of hematopoietic progenitors. Patient BM stromal cells displayed normal hematopoiesis supporting capacity indicated by the CFC number in the nonadherent cell fraction of LTBMCs recharged with normal CD34+ cells. Culture supernatants displayed normal stromal derived factor-1 and stem cell factor/kit ligand but increased flt-3 ligand levels. These findings provide support for the use of autologous stem cell transplantation in MS patients. The low clonogenic potential of BM hematopoietic progenitors probably reflects the presence of activated T cells rather than an intrinsic defect.     

Increased Frequency of Monoclonal Gammopathy of Undetermined Significance in Patients With Nonimmune Chronic Idiopathic Neutropenia Syndrome

This study describes the frequency of monoclonal gammopathy of undetermined significance (MGUS) and the changes in some inflammation-related serum proteins in 157 patients with nonimmune chronic idiopathic neutropenia syndrome (NI-CINS). Of these patients, 42 had pronounced neutropenia with neutrophil counts < 1500/microL, and 115 had mild neutropenia with neutrophil counts ranging from 1500 to 2499/microL. Sixty-six volunteers served as healthy control subjects and 157 age- and sex-matched patients hospitalized for nonmalignant diseases served as patient control subjects. We found that 28.6% of patients with pronounced neutropenia and 14.8% of patients with mild neutropenia had increased serum gamma globulins (above the 95% confidence limit of values of the control subjects). In the group of patients with pronounced neutropenia, 30.9% had increased immunoglobulin (Ig)G values and 23.8% had increased IgA values. In the group of patients with mild neutropenia, 17.4% had increased IgG values and 21.7% had increased IgA values. IgG and IgA values strongly correlated with the neutrophil count. No changes in serum IgM were found. Three of 42 patients with pronounced neutropenia (7.14%) and 3 of 115 patients with mild neutropenia (2.61%) had serum immunofixation tests which showed a small monoclonal spike--4 were IgG-kappa type, 1 was IgG-lambda type, and 1 was IgA-kappa type. None of the healthy or patient control subjects had any evidence of MGUS. No significant changes in the amount of monoclonal spikes were documented during an 18- to 143-month follow-up (median, 58 months). Except for significantly increased alpha1-antitrypsin levels, there were no significant differences in the levels of acute-phase proteins studied between the study patients and the control subjects. These findings are consistent with our previous report suggesting the possible existence of an unrecognized low-grade chronic inflammation in patients with NI-CINS, which may be involved in the pathogenesis of neutropenia in the affected subjects.     

Increased Mobilization of Mesenchymal Stem Cells in Patients With Essential Hypertension: The Effect of Left Ventricular Hypertrophy

Stem cells have great clinical significance in many cardiovascular diseases. However, there are limited data regarding the involvement of mesenchymal stem cells (MSCs) in the pathophysiology of arterial hypertension. The aim of this study was to investigate the circulation of MSCs in patients with essential hypertension. The authors included 24 patients with untreated essential hypertension and 19 healthy individuals. Using flow cytometry, MSCs in peripheral blood, as a population of CD45−/CD34−/CD90+ cells and also as a population of CD45−/CD34−/CD105+ cells, were measured. The resulting counts were translated into the percentage of MSCs in the total cells. Hypertensive patients were shown to have increased circulating CD45−/CD34−/CD90+ compared with controls (0.0069%±0.012% compared with 0.00085%±0.0015%, respectively; P=.039). No significant difference in circulating CD45−/CD34−/CD105+ cells was found between hypertensive patients'' and normotensive patients'' peripheral blood (0.018%±0.013% compared with 0.015%±0.014%, respectively; P=.53). Notably, CD45−/CD34−/CD90+ circulating cells were positively correlated with left ventricular mass index (LVMI) (r=0.516, P<.001). Patients with essential hypertension have increased circulating MSCs compared with normotensive patients, and the number of MSCs is correlated with LVMI. These findings contribute to the understanding of the pathophysiology of hypertension and might suggest a future therapeutic target.

In recent years there has been growing interest in the role of adult stem cells in the pathophysiology of cardiovascular diseases. Although it used to be believed that mammalian cardiomyocytes cease replication soon after birth and that the subsequent growth of the heart was attributable only to cardiomyocyte hypertrophy, newer studies have demonstrated a small degree of cardiogenesis and cardiomyocyte turnover that occurs throughout life.¹, ² These findings led to further research into the contribution of stem cells to the pathophysiology of cardiovascular disorders that has raised the hope of developing new therapeutic approaches. Stem cells have the potential for self‐renewal and differentiation and are the origin cells of various mature cells.Mesenchymal stem cells (MSCs) are also known to have a highly plastic differentiation potential that includes not only adipogenesis, osteogenesis, and chondrogenesis, but also endothelial, cardiovascular,³ and neovascular differentiation.⁴, ⁵, ⁶ Although present in only very small numbers in peripheral blood, in recent years stem and progenitor cells have been implicated in ventricular remodeling and are thought to be of great clinical significance in the pathophysiology of heart failure and atheromatosis. Previous studies have indicated that MSCs derived from peripheral blood, apart from their multilineage potential, can also be used for cellular and gene therapies.⁷ Human MSCs isolated from adult bone marrow provide a model for the development of stem cell therapeutics and could find application in the cardiovascular system—although this is still under investigation.⁸ Under normal conditions, endogenous cardiac progenitor cells are responsible for homeostasis in the heart.⁹ However, it appears that under conditions of stress, this may change, with stem cells from extra‐cardiac sources also playing a role. An interesting experimental study has shown that an increase in preload results in the mobilization of progenitor cells from the bone marrow for use in neovascularization, which plays an important role in cardiac hypertrophy.¹⁰ There are indications that the recruitment of bone marrow–derived cells is involved in cardiac myocyte hypertrophy and maintenance of function in response to pressure overload.¹¹ A recent study from our department has shown increased expression of myocardin and GATA4 genes in the peripheral blood mononuclear cell fraction of hypertensive patients, implying the presence of mesenchymal progenitor cells in the peripheral blood that could possibly be intended to differentiate into cells of the cardiac series.¹² Interestingly, in the patients in that study, myocardin and GATA4 expression was associated with both blood pressure (BP) levels and left ventricular hypertrophy (LVH).To date, most published reports concerning the cardiovascular applications of stem cells have focused on their role in myocardial infarction and in heart failure. Very little work has been done on arterial hypertension, and most has concerned endothelial progenitor cells. The role and behavior of MSCs in patients with essential hypertension is unknown. In a recent animal study, it was shown that the degree to which angiotensin II increased neointima formation was statistically correlated with the increased incorporation of fluorescent bone marrow–derived smooth muscle cells, and that this was inhibited by angiotensin‐1 receptor antagonism.¹³ Based on the hypothesis that MSCs participate in pathophysiological processes that contribute to hypertension, and on the assumption that the behavior of MSCs is altered in hypertensive patients, we carried out the first flow cytometric analysis of CD45−/CD34−/CD90+ and CD45−/CD34−/CD105+ in the peripheral blood of those patients compared with healthy individuals.     

PDE5 inhibition against acute renal ischemia reperfusion injury in rats: does vardenafil offer protection?

Purpose

To evaluate the effect of vardenafil on renal function after renal ischemia–reperfusion (IR) injury (IRI) in a rat model.

Materials and methods

Seventy-one Wistar rats were divided into 7 groups including (1) a vehicle-treated group, (2) a vehicle pretreated-IR group, (3–6) vardenafil pretreated-IR groups in doses of 0.02, 0.2, 2 and 20 μg/kg, respectively, (7) a group of IR followed by treatment with 2 μg/kg of vardenafil. Vardenafil or vehicle solution was administered one hour before unilateral nephrectomy and the induction of 45 min of ischemia on the contralateral kidney by clamping of renal pedicle. Four hours of reperfusion were allowed after renal ischemia. Studied parameters were serum creatinine, fractional excretion of sodium (FENa), and histological evaluation of renal specimens. In addition, renal tissue cGMP levels, ERK1/2 phosphorylation as well as renal function by renal scintigraphy were also evaluated.

Results

Administration of vardenafil before the induction of ischemia resulted in a significant reduction in creatinine and FENa levels as well as in less histological lesions observed in treated kidneys in comparison with the vehicle-treated group. The underlying mechanism of cytoprotection was cGMP depended and involved the phosphorylation of ERK proteins. Renal scintigraphy confirmed that PDE5 inhibition attenuates renal IRI.

Conclusions

Vardenafil attenuates renal IRI. Based on similar results from relevant studies on other PDE-5 inhibitors in renal and cardiac IRI, it can be assumed that all PDE-5 inhibitors share a common mechanism of cytoprotection.