Chronic Lymphocytic Leukemia (CLL) with Borderline Immunoglobulin Heavy Chain Mutational Status, a Rare Subgroup of CLL with Variable Disease Course.

Chronic lymphocytic leukemia (CLL) exhibits substantial variability in disease course. The mutational status of the B-cell receptor immunoglobulin heavy variable (IGHV) chain is a critical prognostic factor, categorizing patients into mutated (M-IGHV) and unmutated (U-IGHV) groups. Recently, a third subgroup with borderline mutational status (BL-IGHV) has been identified, comprising approximately 5% of CLL cases. This study retrospectively analyzes the outcomes of 30 BL-IGHV mutated patients among a cohort of 653 CLL patients, focusing on time to first treatment (TTFT) and overall survival (OS). BL-IGHV patients had a short TTFT similar to U-IGHV patients (median 30.2 vs. 34 months; p = 0.9). Conversely, the OS of BL-IGHV patients resembled M-IGHV patients (median NR vs. 258 months; p = 1). Despite a similar incidence in unfavorable prognostic factors, the TTFT was shorter compared to other published cohorts. However, striking similarities with other experiences suggest that BL-IGHV mutated patients share common biological characteristics, biased IGHV gene usage and BCR subset frequency. These findings also underscore the need for multicentric efforts aggregating data on BL-IGHV CLL in order to elucidate its disease course and optimize therapeutic approaches for this rare subgroup. Until then, predicting outcomes and optimal management of BL-IGHV CLL will remain challenging.

Focal adhesion kinase activation by calcium-dependent calpain is involved in chronic lymphocytic leukaemia cell aggressiveness.

Signalling events downstream the B-cell receptor (BCR) are central for the survival and progression of chronic lymphocytic leukaemia (CLL) cells. Focal adhesion kinase (FAK), regulated through calpain, interacts with molecules of BCR signalling, cytoskeletal modelling and disease progression, such as Src/Lyn, cortactin and HS1. Hypothesizing that FAK might play a key role in CLL pathogenesis, we observed a down-modulation of FAK whole form, associated with FAK cleavage due to calpain activity upon BCR stimulation. Patients, whose cells were able to release Ca++ after BCR stimulation, had less amount of full-length FAK, which translated into a higher presence of cleaved/activated form of the protein phosphorylated at Y397, these features being mostly shown by immunoglobulin heavy chain (IGHV)-unmutated poor-prognosis patients. Moreover, we found that cortactin and HS1 proteins were overexpressed in those cells, suggesting a possible interplay with FAK. Treatment with the FAK inhibitor Defactinib was able to induce apoptosis in CLL cells. In conclusion, the malignant phenotype in unfavourable-prognosis patients seems to be encouraged by the overexpression of cortactin and HS1, that, together with FAK, may be involved in a druggable pathogenetic pathway in CLL.

Tracing angiotensin II's yin-yang effects on cardiovascular-renal pathophysiology.

Adverse changes in cardiovascular and renal systems are major contributors to overall morbidity and mortality. Human cardiovascular and renal systems exhibit a complex network of positive and negative feedback that is reflected in the control of vascular tone via angiotensin II (Ang II) based signaling. This review will examine in some depth, the multiple components and processes that control the status and reflect the health of these various cardiovascular and renal systems, such as pathways associated to monomeric G proteins, RhoA/Rho kinase system and ERK, oxidative stress and NO balance. It will specifically emphasize the "yin-yang" nature of Ang II signaling by comparing and contrasting the effects and activity of various systems, pathways and components found in hypertension to those found in Gitelman's and Bartter's syndromes (GS/BS), two rare autosomal recessive tubulopathies characterized by electrolytic imbalance, metabolic alkalosis, sodium wasting and prominent activation of the renin-angiotensin-aldosterone system. Notwithstanding the activation of the renin-angiotensin-aldosterone system, GS/BS are normo-hypotensive and protected from cardiovascular-renal remodeling and therefore can be considered the mirror image, the opposite of hypertension.

Targeting of HSP70/HSF1 Axis Abrogates In Vitro Ibrutinib-Resistance in Chronic Lymphocytic Leukemia.

The Btk inhibitor ibrutinib has significantly changed the management of chronic lymphocytic leukemia (CLL) patients. Despite its clinical efficacy, relapses occur, and outcomes after ibrutinib failure are poor. Although BTK and PLCγ2 mutations have been found to be associated with ibrutinib resistance in a fair percentage of CLL patients, no information on resistance mechanisms is available in patients lacking these mutations. The heat shock protein of 70 kDa (HSP70) and its transcription factor heat shock factor 1 (HSF1) play a role in mediating the survival and progression of CLL, as well as taking part in drug resistance in various cancers. We demonstrated that resveratrol and related phenols were able to induce apoptosis in vitro in leukemic cells from CLL untreated patients by acting on the HSP70/HSF1 axis. The same was achieved in cells recovered from 13 CLL patients failing in vivo ibrutinib treatment. HSP70 and HSF1 levels decreased following in vitro treatment, correlating to apoptosis induction. We suggest an involvement of HSP70/HSF1 axis in controlling resistance to ibrutinib in CLL cells, since their inhibition is effective in inducing in vitro apoptosis in cells from ibrutinib refractory patients. The targeting of HSP70/HSF1 axis could represent a novel rational therapeutic strategy for CLL, also for relapsing patients.

Prognostic and Predictive Effect of IGHV Mutational Status and Load in Chronic Lymphocytic Leukemia: Focus on FCR and BR Treatments.

BACKGROUND: Most important markers in chronic lymphocytic leukemia (CLL) are TP53 abnormalities, including mutations and deletions, and the mutational status of immunoglobulin heavy chain (IGHV) genes. However, some recent publications suggest that the IGHV mutational load could have a prognostic effect on CLL patients. PATIENTS AND METHODS: We performed a single-center retrospective study on 459 patients with productive rearrangement of the B-cell receptor to evaluate the prognostic and predictive role of IGHV mutational status and burden within the germline sequence. In particular we focused on FCR (fludarabine with cyclophosphamide, and rituximab)- (64 naive and 30 relapsed) and BR (bendamustine with rituximab)-treated patients (17 naive and 61 relapsed). A cutoff value of 2% of difference within the IGHV germline was used to define the IGHV mutational status. RESULTS: We reported that unmutated IGHV (U-IGHV) patients were characterized by a significant shorter progression-free survival (PFS) and overall survival (P < .0001) compared with mutated IGHV (M-IGHV) patients. Moreover, treatment-naive M-IGHV patients experienced a long-term disease control after FCR or BR, with PFS reaching a plateau regardless of mutational load. In our series the extent of IGHV gene mutation did not provide further relevant prognostic data over the mutational status. Relapsed patients showed dismal outcome with chemoimmunotherapy regardless of IGHV status or load. CONCLUSION: Our data, together with from those from the literature, confirmed the cutoff value of 2% to define the mutational status of IGHV gene and suggest that FCR/BR are good first-line treatment strategies for M-IGHV patients, whereas U-IGHV patients should be managed with B-cell receptor and/or B-cell lymphoma 2 (BCL2) inhibitors.

Oxidative Stress and Cardiovascular-Renal Damage in Fabry Disease: Is There Room for a Pathophysiological Involvement?

Fabry disease is an X-linked lysosomal storage disease caused by mutations in the GLA gene that lead to a reduction or an absence of the enzyme α-galactosidase A, resulting in the progressive and multisystemic accumulation of globotriaosylceramide. Clinical manifestation varies from mild to severe, depending on the phenotype. The main clinical manifestations are cutaneous (angiokeratomas), neurological (acroparesthesias), gastrointestinal (nausea, diarrhea abdominal pain), renal (proteinuria and kidney failure), cardiovascular (cardiomyopathy and arrhythmias), and cerebrovascular (stroke). A diagnosis of Fabry disease can be made with an enzymatic assay showing absent or reduced α-galactosidase A in male patients, while in heterozygous female patients, molecular genetic testing is needed. Enzyme replacement therapy (ERT) with recombinant human α-galactosidase is nowadays the most-used disease-specific therapeutic option. Despite ERT, cardiocerebrovascular-renal irreversible organ injury occurs, therefore additional knowledge and a deeper understanding of further pathophysiological mechanisms leading to end organ damage in Fabry disease are needed. Recent data point toward oxidative stress, oxidative stress signaling, and inflammation as some such mechanisms. In this short review, the current knowledge on the involvement of oxidative stress in cardiovascular-renal remodeling is summarized and related to the most recent evidence of oxidative stress activation in Fabry disease, and clearly points toward the involvement of oxidative stress in the pathophysiology of the medium- to long-term cardiovascular-renal damage of Fabry disease.

Oxidative stress and the altered reaction to it in Fabry disease: A possible target for cardiovascular-renal remodeling?

BACKGROUND: Fabry disease is characterized by deficient expression/activity of α-GalA with consequent lysosomal accumulation in various organs of its substrate Gb3. Despite enzyme replacement therapy, Fabry disease progresses with serious myocardial, cerebral and renal manifestations. Gb3 accumulation may induce oxidative stress (OxSt), production of inflammatory cytokines and reduction of nitric oxide, which may impact on Fabry disease's clinical manifestations. METHODS: OxSt status was characterized in 10 patients compared with 10 healthy subjects via protein expression of p22phox, subunit of NADH/NADPH oxidase, (Western blot), Heme oxygenase (HO)-1 levels (ELISA), antioxidant/anti-inflammatory, lipid peroxidation as malondialdehyde (MDA) production (colorimetric assay), phosphorylation state of Extracellular Signal Regulated Kinase (ERK)1/2 and Myosin Phosphatase Target Protein (MYPT)-1 (Western blot), marker of Rho kinase activation, both involved in OxSt signaling. Cardiac left ventricular (LV) mass was also evaluated (M-mode echocardiography). RESULTS: LV mass was higher in Fabry's males (123.72±2.03SEM g/m2) and females (132.09±6.72g/m2). p22phox expression was also higher in patients (1.04±0.09 d.u. vs 0.54±0.05 d.u. p<0.01) as well as MDA levels (54.51±3.97 vs 30.05±7.11 nmol/mL p = 0.01) while HO-1 was reduced (8.84±0.79 vs 14.03±1.23 ng/mL, p<0.02). MYPT-1's phosphorylation was increased in patients (0.52±0.11 d.u. vs 0.03±0.08 d.u., p<0.01) while phosphorylation of ERK1/2 was reduced (0.91±0.08 d.u. vs 1.53±0.17 d.u., p = 0.004). CONCLUSIONS: This study documents OxSt activation and the altered reaction to it in Fabry patients. Cardiac remodeling, Rho kinase signaling activation and reduction of protective HO-1 might suggest that, in addition to enzyme replacement therapy, OxSt inhibition by either pharmacological or nutritional measures, is likely to prove useful for the prevention/treatment of Fabry patients' cardiovascular-renal remodeling.

STAT3 mutation impacts biological and clinical features of T-LGL leukemia.

STAT3 mutations have been described in 30-40% of T-large granular lymphocyte (T-LGL) leukemia patients, leading to STAT3 pathway activation. Considering the heterogeneity of the disease and the several immunophenotypes that LGL clone may express, the aim of this work was to evaluate whether STAT3 mutations might be associated with a distinctive LGL immunophenotype and/or might be indicative for specific clinical features. Our series of cases included a pilot cohort of 101 T-LGL leukemia patients (68 CD8+/CD4- and 33 CD4+/CD8±) from Padua Hematology Unit (Italy) and a validation cohort of additional 20 patients from Rennes Hematology Unit (France). Our results indicate that i) CD8+ T-LGL leukemia patients with CD16+/CD56- immunophenotype identify a subset of patients characterized by the presence of STAT3 mutations and neutropenia, ii) CD4+/CD8± T-LGL leukemia are devoid of STAT3 mutations but characterized by STAT5b mutations, and iii) a correlation exists between STAT3 activation and presence of Fas ligand, this molecule resulting highly expressed in CD8+/CD16+/CD56- patients. Experiments with stimulation and inhibition of STAT3 phosphorylation confirmed this relationship. In conclusion, our data show that T-LGL leukemia with specific molecular and phenotypic patterns is associated with discrete clinical features contributing to get insights into molecular bases accounting for the development of Fas ligand-mediated neutropenia.

Endothelin-1 Drives Epithelial-Mesenchymal Transition in Hypertensive Nephroangiosclerosis.

BACKGROUND: Tubulointerstitial fibrosis, the final outcome of most kidney diseases, involves activation of epithelial mesenchymal transition (EMT). Endothelin-1 (ET-1) activates EMT in cancer cells, but it is not known whether it drives EMT in the kidney. We therefore tested the hypothesis that tubulointerstitial fibrosis involves EMT driven by ET-1. METHODS AND RESULTS: Transgenic TG[mRen2]27 (TGRen2) rats developing fulminant angiotensin II-dependent hypertension with prominent cardiovascular and renal damage were submitted to drug treatments targeted to ET-1 and/or angiotensin II receptor or left untreated (controls). Expressional changes of E-cadherin and α-smooth muscle actin (αSMA) were examined as markers of renal EMT. In human kidney HK-2 proximal tubular cells expressing the ETB receptor subtype, the effects of ET-1 with or without ET-1 antagonists were also investigated. The occurrence of renal fibrosis was associated with EMT in control TGRen2 rats, as evidenced by decreased E-cadherin and increased αSMA expression. Irbesartan and the mixed ET-1 receptor antagonist bosentan prevented these changes in a blood pressure-independent fashion (P < 0.001 for both versus controls). In HK-2 cells ET-1 blunted E-cadherin expression, increased αSMA expression (both P < 0.01), collagen synthesis, and metalloproteinase activity (P < 0.005, all versus untreated cells). All changes were prevented by the selective ETB receptor antagonist BQ-788. Evidence for involvement of the Rho-kinase signaling pathway and dephosphorylation of Yes-associated protein in EMT was also found. CONCLUSIONS: In angiotensin II-dependent hypertension, ET-1 acting via ETB receptors and the Rho-kinase and Yes-associated protein induces EMT and thereby renal fibrosis.

Integrated CLL Scoring System, a New and Simple Index to Predict Time to Treatment and Overall Survival in Patients With Chronic Lymphocytic Leukemia.

INTRODUCTION: Several prognostic factors have been identified to predict the outcome of patients with chronic lymphocytic leukemia (CLL), but only a few studies analyzed more markers together. PATIENTS AND METHODS: Taking advantage of a population of 608 patients, we identified the strongest prognostic markers of survival and, subsequently, in a cohort of 212 patients we integrated data of cytogenetic lesions, IGHV mutational status, and CD38 expression in a new and easy scoring system we called the integrated CLL scoring system (ICSS). ICSS defines 3 groups of risk: (1) low risk (patients with 13q(-) or normal fluorescence in-situ hybridization analysis results, mutated IGHV, and CD38) (2) high risk (all 11q(-) or 17p(-) patients and/or all unmutated IGHV and CD38(+) patients); and (3) intermediate risk (all remaining patients). RESULTS: Using only these 3 already available prognostic factors, we were able to properly redefine patients and better predict the clinical course of the disease. CONCLUSION: ICSS could become a useful tool for CLL patients' management.

p66Shc deletion or deficiency protects from obesity but not metabolic dysfunction in mice and humans.

AIMS/HYPOTHESIS: Oxygen radicals generated by p66Shc drive adipogenesis, but contradictory data exist on the role of p66Shc in the development of obesity and the metabolic syndrome. We herein explored the relationships among p66Shc, adipose tissue remodelling and glucose metabolism using mouse models and human adipose tissue samples. METHODS: In wild-type (WT), leptin-deficient (ob/ob), p66Shc(-/-) and p66Shc(-/-) ob/ob mice up to 30 weeks of age, we analysed body weight, subcutaneous and visceral adipose tissue histopathology, glucose tolerance and insulin sensitivity, and liver and muscle fat accumulation. A group of mice on a high fat diet (HFD) was also analysed. A parallel study was conducted on adipose tissue collected from patients undergoing elective surgery. RESULTS: We found that p66Shc(-/-) mice were slightly leaner than WT mice, and p66Shc(-/-) ob/ob mice became less obese than ob/ob mice. Despite their lower body weight, p66Shc(-/-) mice accumulated ectopic fat in the liver and muscles, and were glucose intolerant and insulin resistant. Features of adverse adipose tissue remodelling induced by obesity, including adipocyte enlargement, apoptosis, inflammation and perfusion were modestly and transiently improved by p66Shc (also known as Shc1) deletion. After 12 weeks of the HFD, p66Shc(-/-) mice were leaner than but equally glucose intolerant and insulin resistant compared with WT mice. In 77 patients, we found a direct correlation between BMI and p66Shc protein levels. Patients with low p66Shc levels were less obese, but were not protected from other metabolic syndrome features (diabetes, dyslipidaemia and hypertension). CONCLUSIONS/INTERPRETATION: In mice and humans, reduced p66Shc levels protect from obesity, but not from ectopic fat accumulation, glucose intolerance and insulin resistance.

JAK/STAT/PKCδ molecular pathways in synovial fluid T lymphocytes reflect the in vivo T helper-17 expansion in psoriatic arthritis.

Looking to the sustained psoriatic arthritis (PsA) joint as a model of local human inflammation, this study was designed to assess the T lymphocyte signal transduction pathways potentially involved in this chronic immune-mediated inflammatory process, as characterized by direct ex vivo analysis of T helper (Th)-17 T effector (Teff) cell phenotypes in synovial fluid (SF) and peripheral blood (PB) of clinically active PsA patients. The reverse-phase protein arrays (RPPA) technique was employed to identify STAT3, STAT1, JAK1, JAK2, PKCδ and ERK1/2 phosphoprotein levels on total T cell lysates in SF samples of PsA patients. Frequencies of T CD4(+)IL-17A-F(+) and T CD4(+)IL-23R(+) Th17 cells were quantified in SF and matched PB of PsA patients by flow cytometry and compared with PB of healthy controls (HC). Increased levels of JAK1, STAT3, STAT1 and PKCδ phosphoproteins were found in SF T cells of PsA patients, compared with PB of HC. The expansion of T CD4(+)IL-17A-F(+) cells, as well as of T CD4(+) cells expressing IL-23Rp19 (T CD4(+) IL-23R(+)), considered as the pathogenic phenotype of effector Th17 cells, was found to be confined to the joints of PsA patients, as the frequencies of both populations were significantly higher in SF than in matched PB, or in PB of HC. In conclusion, T lymphocyte signal transduction pathway mapping revealed an enhanced activation of JAK1/STAT3/STAT1 and PKCδ phosphoproteins that may drive the local inflammatory process, characterized by the in vivo expansion of T CD4(+)IL-17A-F(+) and T CD4(+)IL-23R(+) Th17 Teff cells in SF of clinically active joints of PsA patients.

Myeloid calcifying cells promote atherosclerotic calcification via paracrine activity and allograft inflammatory factor-1 overexpression.

Several cell types contribute to atherosclerotic calcification. Myeloid calcifying cells (MCCs) are monocytes expressing osteocalcin (OC) and bone alkaline phosphatase (BAP). Herein, we tested whether MCCs promote atherosclerotic calcification in vivo. We show that the murine spleen contains OC(+)BAP(+) cells with a phenotype similar to human MCCs, a high expression of adhesion molecules and CD11b, and capacity to calcify in vitro and in vivo. Injection of GFP(+) OC(+)BAP(+) cells into 8- or 40-week ApoE(-/-) mice led to more extensive calcifications in atherosclerotic areas after 24 or 4 weeks, respectively, compared to control OC(-)BAP(-) cells. Despite that OC(+)BAP(+) cells had a selective transendothelial migration capacity, tracking of the GFP signal revealed that presence of injected cells within atherosclerotic areas was an extremely rare event and so GFP mRNA was undetectable by qPCR of lesion extracts. By converse, injected OC(+)BAP(+) cells persisted in the bloodstream and bone marrow up to 24 weeks, suggesting a paracrine effect. Indeed, OC(+)BAP(+) cell-conditioned medium (CM) promoted calcification by cultured vascular smooth muscle cells (VSMC) more than CM from OC(-)BAP(-) cells. A genomic and proteomic investigation of MCCs identified allograft inflammatory factor (AIF)-1 as a potential candidate of this paracrine activity. AIF-1 stimulated VSMC calcification in vitro and monocyte-specific (CD11b-driven) AIF-1 overexpression in ApoE(-/-) mice increased calcium content in atherosclerotic areas. In conclusion, we show that murine OC(+)BAP(+) cells correspond to human MCCs and promote atherosclerotic calcification in ApoE(-/-) mice, through paracrine activity and modulation of resident cells by AIF-1 overexpression.

Endothelial progenitor cells relationships with clinical and biochemical factors in a human model of blunted angiotensin II signaling.

Angiotensin II (Ang II) is essential for endothelial progenitor cells (EPCs) function as Ang-II-induced oxidative stress causes senescence of EPCs and endothelial dysfunction and Ang II type 1 receptor blockers increase EPCs. Moreover, EPCs activity is dependent on nitric oxide (NO) and heme oxygenase (HO)-1 as these correlate with EPCs senescence and are reduced in hypertensives. Bartter's/Gitelman's syndrome patients (BS/GS), have increased Ang II yet normo/hypotension along with blunted Ang II signaling, reduced oxidative stress, increased NO and HO-1, thus presenting a unique system to explore EPC biology and its relationship with vascular clinical and biochemical correlates. Circulating EPCs, NO-dependent vasodilation (flow-mediated dilation (FMD)) and HO-1 gene expression were characterized in 10 BS/GS patients and in 10 normotensive subjects. EPCs defined by cell surface antigens CD34+kinase-insert domain receptor (KDR+), CD133+KDR+ and CD133+CD34+KDR+ cells were quantitiated via direct three-color flow-cytometry analysis, HO-1 gene expression by reverse transcription-PCR and FMD by B-mode echo scan of the right brachial artery. Correlation analysis was carried out regarding FMD and EPCs, FMD and HO-1 and EPCs and HO-1. In BS/GS, CD34+KDR+ cell numbers did not differ from controls while CD133+KDR+ and CD133+CD34+KDR+ cell numbers were higher. HO-1 gene expression, as well as FMD, was higher in BS/GS compared with controls. Both CD133+KDR+ and CD133+CD34+KDR+ strongly correlated with both FMD and HO-1. FMD and HO-1 were also strongly correlated. These results document in a human system that EPC numbers and specific populations are related to important clinical and biochemical factors involved in cardiovascular (CV) status and reaffirm the utility of BS/GS patients as a useful system to investigate EPC's role(s) in the pathophysiology of cardiovascular remodeling in humans.

Effects of androgens on endothelial progenitor cells in vitro and in vivo.

The beneficial or detrimental effects of androgens on the cardiovascular system are debated. Endothelial progenitor cells are bone-marrow-derived cells involved in endothelial healing and angiogenesis, which promote cardiovascular health. Oestrogens are potent stimulators of endothelial progenitor cells, and previous findings have indicated that androgens may improve the biology of these cells as well. In the present study, we show that testosterone and its active metabolite dihydrotestosterone exert no effects on the expansion and function of late endothelial progenitors isolated from the peripheral blood of healthy human adult males, whereas they positively modulate early 'monocytic' endothelial progenitor cells. In parallel, we show that castration in rats is followed by a decrease in circulating endothelial progenitor cells, but that testosterone and dihydrotestosterone replacement fails to restore endothelial progenitor cells towards normal levels. This is associated with persistently low oestrogen levels after androgen replacement in castrated rats. In a sample of 62 healthy middle-aged men, we show that circulating endothelial progenitor cell levels are more directly associated with oestradiol, rather than with testosterone, concentrations. In conclusion, our results collectively demonstrate that androgens exert no direct effects on endothelial progenitor cell biology in vitro and in vivo.

Gender differences in endothelial progenitor cells and cardiovascular risk profile: the role of female estrogens.

OBJECTIVE: Endothelial progenitor cells (EPCs) participate in vascular homeostasis and angiogenesis. The aim of the present study was to explore EPC number and function in relation to cardiovascular risk, gender, and reproductive state. METHODS AND RESULTS: As measured by flow-cytometry in 210 healthy subjects, CD34(+)KDR(+) EPCs were higher in fertile women than in men, but were not different between postmenopausal women and age-matched men. These gender gradients mirrored differences in cardiovascular profile, carotid intima-media thickness, and brachial artery flow-mediated dilation. Moreover, EPCs and soluble c-kit ligand varied in phase with menstrual cycle in ovulatory women, suggesting cyclic bone marrow mobilization. Experimentally, hysterectomy in rats was followed by an increase in circulating EPCs. EPCs cultured from female healthy donors were more clonogenic and adherent than male EPCs. Treatment with 17beta-estradiol stimulated EPC proliferation and adhesion, via estrogen receptors. Finally, we show that the proangiogenic potential of female EPCs was higher than that of male EPCs in vivo. CONCLUSIONS: EPCs are mobilized cyclically in fertile women, likely to provide a pool of cells for endometrial homeostasis. The resulting higher EPC levels in women than in men reflect the cardiovascular profile and could represent one mechanism of protection in the fertile female population.

Carnitine-mediated improved response to erythropoietin involves induction of haem oxygenase-1: studies in humans and in an animal model.

BACKGROUND: Carnitine improves erythropoetin (EPO) response and anaemia in haemodialysis patients (HD); however, the mechanism(s) responsible remain unidentified. We have reported that carnitine induces haem oxygenase (HO)-1, which is an antioxidant and antiapoptotic that acts via pathways shared with EPO. Therefore carnitine's effect on these pathways may account for the improved EPO response. This study evaluates carnitine's effect on protein expression of HO-1 in unexplained EPO resistant HD. Carnitine's effect was assessed by HO-1 expression in patients and compared to its antiapoptotic effect via HO-1 induction in a rat model of carnitine-treated heart failure. METHODS: Unexplained EPO resistant HD mononuclear cell HO-1 and rat gastrocnemious muscle HO-1 and Bcl-2 protein expression were evaluated by western blot. RESULTS: HD's haemoglobin (Hb) and haematocrit (Ht) were not different before carnitine treatment: 8.8 +/- 0.4 mg/dl versus 8.98 +/- 0.13 and 30.20% +/- 0.84 versus 30.72 +/- 1.14, respectively. Carnitine increased HO-1, Hb and Ht compared with patients not treated with carnitine: 2.40 +/- 0.58 versus 1.49 +/- 0.41, P = 0.02; 11.22 +/- 0.54 versus 8.90 +/- 0.15, P < 0.0001; 32.72 +/- 1.77 versus 30.66 +/- 0.43, P = 0.035, respectively. Carnitine-treated HD's HO-1 significantly correlated with haemoglobin. HO-1 and Bcl-2 protein levels in untreated heart failure rat's gastrocnemious muscle were reduced when compared with controls: 3.41 +/- 0.49 versus 5.32 +/- 0.38 and 0.69 +/- 0.11 versus 1.65 +/- 0.37, respectively, but were higher in carnitine-treated heart failure rats: 4.8 +/- 0.32 versus 3.41 +/- 0.49, P < 0.0002 and 1.09 +/- 0.08 versus 0.69 +/- 0.11, P = 0.0007, respectively. CONCLUSIONS: These results are consistent with an involvement of HO-1 in carnitine's effect on erythropoiesis. The initial signals or effectors responsible for carnitine's effect remain to be identified.