Shyh-Chyi Lo

Endothelial Progenitor Cells in Primary Aldosteronism: A Biomarker of Severity for Aldosterone Vasculopathy and Prognosis

CONTEXT Primary aldosteronism (PA) is associated with a higher incidence of cardiovascular events, probably through mineralocorticoid receptor (MR)-dependent endothelial cell dysfunction, in comparison with essential hypertension (EH). OBJECTIVE Our objective was to investigate the number and function of endothelial progenitor cells (EPC) in PA and the relationship with arterial stiffness and disease progression. DESIGN AND SETTING We conducted a prospective study of the change of EPC number and outcome of PA patients after treatment at a tertiary medical center. PRIMARY OUTCOMES Changes in arterial stiffness and EPC number after treatment and the curability of hypertension were assessed. PATIENTS A total of 113 PA patients (87 patients diagnosed with aldosterone-producing adenoma, 26 with idiopathic hyperaldosteronism) and 55 patients with EH participated. RESULTS PA patients had higher arterial stiffness than EH patients (P = 0.006), with a lower numbers of circulating EPC and endothelial colony-forming units (P < 0.05). The differences were ameliorated at 6 months after unilateral adrenalectomy or treatment with spironolactone. Expression of MR was identified in the EPC. The number of circulating EPC was inversely correlated with the plasma aldosterone concentration (P = 0.021), arterial stiffness (P = 0.029) and serum high-sensitivity C-reactive protein (P = 0.03). High-dose aldosterone (10(-5) and 10(-6) m) attenuated EPC proliferation and angiogenesis in vitro. Among the 45 patients who underwent unilateral adrenalectomy, 32 (71%) were cured of hypertension. The preoperative number of EPC [log(EPC number percent) >-3.6] predicted the curability of hypertension after adrenalectomy (P = 0.003). CONCLUSIONS The relative deficiency of EPC in PA patients may contribute to aldosterone vasculopathy, which can be reversed by adrenalectomy and spironolactone. High aldosterone levels attenuated EPC proliferation and angiogenesis. Circulating EPC number may be a valuable biomarker to identify PA patients with a high incidence of arterial stiffness and to predict postoperative residual hypertension of aldosterone-producing adenoma.

Increased cardiomyocyte apoptosis following ischemia and reperfusion in diet-induced hypercholesterolemia: relation to Bcl-2 and Bax proteins and caspase-3 activity.

It has been reported that apoptosis is a significant contributor to myocardial cell death as a result of reperfusion injury. However, whether the extent of cardiomyocyte apoptosis following ischemia and reperfusion varies in different pathophysiological backgrounds is still uncertain. In this study, we examined whether hypercholesterolemia increases the extent of myocardial reperfusion injury by aggravating cardiomyocyte apoptosis and the effects of hypercholesterolemia on the expression of Bcl-2 and Bax proteins and the activation of caspase-3. Twenty-eight male New Zealand white rabbits were fed standard chow (control, n=14) or chow supplemented with 1% cholesterol (hypercholesterolemic, n=14) for 8 wk. Anesthetized rabbits were then subjected to 30 min of left circumflex artery occlusion followed by 4 h of reperfusion. Apoptosis was identified as “DNA ladders” by gel electrophoresis and confirmed histologically using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. The infarct size (% of risk region) was significantly greater in hypercholesterolemic rabbits than in controls (39±6 vs. 23±2%, P=0.02). Very few TUNEL-positive cardiomyocytes could be identified in the nonischemic regions in both groups, consistent with an absence of DNA laddering. In contrast, TUNEL-positive cardiomyocytes were significantly displayed in the ischemic, nonnecrotic myocardium, and DNA ladder occurred in all animals. The percentage of TUNEL-positive cardiomyocytes in the ischemic nonnecrotic myocardium was significantly higher in hypercholesterolemic rabbits compared with controls (40±5 vs. 17±1%, P<0.001). Western blot analysis showed that, in the nonischemic myocardium, hypercholesterolemic rabbits exhibited an approximately 50% increase in the expression of Bcl-2 (P<0.05), but not Bax, than control rabbit. However, compared with controls, hypercholesterolemic rabbits exhibited a more pronounced decrease in the expression of Bcl-2 (42±4 vs. 26±2%, P<0.01) and a similar extent of increase in the expression of Bax in the ischemic myocardium. Furthermore, hypercholesterolemic rabbits were associated with a markedly increased activation of caspase-3 within the ischemic myocardium compared to control rabbits. This study demonstrates that although hypercholesterolemia is associated with an increased myocardial Bcl-2/Bax ratio at baseline, it still significantly exacerbates cardiac reperfusion injury, not only by increasing the infarct size but also by increasing the extent of cardiomyocyte apoptosis.

Epitope‐based matching for HLA‐alloimmunized platelet refractoriness in patients with hematologic diseases

BACKGROUND: For HLA‐alloimmunized patients, platelet (PLT) concentrations are provided either at matched HLA‐A and HLA‐B loci or by serologic cross‐reactivity groups (CREG) matching strategy. However, this method has some limitations.

Platelet alloimmunization after long‐term red cell transfusion in transfusion‐dependent thalassemia patients

BACKGROUND: The platelet (PLT) alloimminization status after long‐term red cell (RBC) transfusion in thalassemia patients was investigated, including antibodies against HLA antigens and PLT‐specific glycoprotein antigens.

Severe lymphopenia is associated with elevated plasma interleukin-15 levels and increased mortality during severe sepsis.

ABSTRACT Sepsis-related mortality has been found increased in RAG-1 knockout mice. However, in patients admitted to medical intensive care units, it is unknown whether severe lymphocyte depletion at admission is associated with increased interleukin (IL)-7 and IL-15 levels in circulation, and increased mortality. We prospectively enrolled 92 patients who were admitted to medical intensive care units for severe sepsis or septic shock. At admission, 24 patients (26.1%) had severe lymphopenia, defined as lymphocyte counts of less than 0.5 × 103/&mgr;L. Severe lymphopenia was associated with significantly higher plasma levels of tumor necrosis factor &agr;, IL-6, IL-8, and IL-10 and was also independently associated with 28-day mortality (adjusted hazard ratio, 3.532; 95% confidence interval, 1.482−8.416; P = 0.004). The levels of plasma IL-15, but not IL-7, were increased modestly in patients with severe lymphopenia compared with those without (median, 12.2 vs. 6.4 pg/mL; P = 0.005). The elevated plasma IL-15 levels were contrarily associated with significantly decreased B-cell lymphoma 2 mRNA expression in peripheral blood mononuclear cells. In conclusion, severe lymphopenia was associated with increased mortality in patients with severe sepsis. We found that patients with sepsis with severe lymphopenia had down-regulated B-cell lymphoma 2 mRNA expression in peripheral blood mononuclear cells, despite increased plasma IL-15 concentrations. Whether IL-7 and IL-15 are insufficient in patients with severe lymphopenia during severe sepsis warrants further investigations.

Comparison of corneal epitheliotrophic capacity among different human blood-derived preparations.

Purpose: To compare the corneal epitheliotrophic capacity of different human blood-derived preparations, including cord blood serum (CBS), peripheral blood serum (PBS), and fresh frozen plasma (FFP) on bovine corneal epithelial cells. Materials and Methods: The concentrations of epithelial growth factor, transforming growth factor β1, insulin-like growth factor 1, hyaluronic acid, fibronectin, albumin, glucose, and calcium in different human blood derivatives were evaluated using enzyme-linked immunosorbent assay or biochemical methods. Cultivated bovine corneal epithelial cells were incubated with various blood derivatives, and cell proliferation, migration, and differentiation were evaluated by colorimetric assay, Boyden chamber chemotaxis assay, wounding assay, scanning electron microscopy, and transepithelial electric resistance measurements. Wound closure was assessed using a scratch-induced directional wounding assay. Results: Of the 3 human blood derivatives evaluated, CBS had the highest concentrations of epithelial growth factor, transforming growth factor β1, and hyaluronic acid (P < 0.05). FFP had the lowest concentration of calcium and the highest concentration of glucose (P < 0.05). CBS demonstrated the highest ability to promote cellular proliferation, followed by PBS and FFP (P < 0.05). CBS was also the best in promoting cellular differentiation because scanning electron microscopy demonstrated coherent monolayers of flattened and polygonal-shaped cells with evenly distributed microvilli. Transepithelial electric resistance was noted to be the highest for cells incubated in CBS, indicating formation of well-differentiated cells with functional tight junction (P < 0.05). Cells cultivated with FFP were the least capable of promoting proliferation, migration, and differentiation. Conclusions: Different human blood derivatives may have different concentrations of epitheliotrophic factors. CBS is generally superior to PBS in promoting corneal epithelial proliferation and differentiation.

Effects of memantine on the twitch tension of mouse diaphragm

The effects of memantine (50-175 microM) on the post-tetanic potentiation of the twitch tension were studied on the isolated mouse nerve diaphragm preparation. Memantine completely abolished the twitch tension elicited indirectly while it had no effect on the directly elicited twitch tension. Memantine also decreased the post-tetanic potentiation of amplitude of endplate potential and twitch tension. The duration of tetanic stimulation that induced a maximal decrease of twitch tension was 10-20 s. It is suggested that the effect of memantine on post-tetanic potentiation may be due to its voltage- and time-dependent effect on the ion channel-acetylcholine receptor complex.

Immunological characterization of anti-Mia, a red blood cell alloantibody, in Taiwan

Background and Objectives The red blood cell Mi III phenotype is prevalent in Asia, and its corresponding alloantibody, anti‐Mia, has been reported to cause haemolytic transfusion reactions and haemolytic disease of the newborn. However, a complete picture of the immunological characteristics of anti‐Mia is still lacking. We therefore conducted a systematic study to evaluate the potential clinical significance of this antibody.

Genetic variations of CD36 and low platelet CD36 expression - a risk factor for lipemic plasma donation in Taiwanese apheresis donors.

New CD36 mutations are constantly being identified, although no study has specifically targeted a Taiwanese population. CD36 deficiency can result in dyslipid state and slow clearance of chylomicron. This could be linked to more frequent lipemic donations.

The association of carotid intima-media thickness with serum Level of perfluorinated chemicals and endothelium-platelet microparticles in adolescents and young adults.

Perfluorinated chemicals (PFCs) have been widely used in a variety of products worldwide. Our previous study has documented a close association of higher serum level of perfluorooctane sulfonate (PFOS) with an increased carotid intima-media thickness (CIMT) in a cohort of adolescents and young adults. Herein, we further investigated the association of oxidative stress, circulating endothelial microparticles (EMPs) and platelet microparticles (PMPs) with PFCs and CIMT in humans. We recruited 848 subjects (12-30years old) from a population-based sample to determine the relationship between serum levels of PFCs, EMPs (CD62E and CD31+/CD42a-), PMPs (CD62P and CD31+/CD42a+), and the urine levels of 8-hydroxydeoxyguanosine (8-OHdG) and CIMT. The results showed that CD31+/CD42a- (endothelial apoptosis marker) and CD31+/CD42a+ (platelet apoptosis marker) increased significantly across quartiles of PFOS in multiple linear regression analysis. Furthermore, the elevation of CD31+/CD42a- and CD31+/CD42a+ corresponded to the increase of the odds ratios of thicker CIMT (greater than 50th percentile) with higher serum PFOS concentration (greater than 50%) (OR=2.86, 95% C.I.=1.69-4.84, P<0.001) in logistic regression models. There was no association between PFC concentration and 8-OHdG. In conclusion, we found the positive association between PFOS and CIMT that was more evident when serum levels of EMPs (CD31+/CD42a-) and PMPs (CD31+/CD42a+) were elevated. Further studies are warranted to investigate the causal inference of PFOS exposure on endothelial cell damage and atherosclerosis.