Exploring the impact of high-altitude de-acclimatization on renal function: The roles of oxidative and endoplasmic reticulum stress in rat models

BACKGROUND

High-altitude de-acclimatization (HADA) significantly impacts physiological functions when individuals acclimatize to high altitudes return to lower altitudes. This study investigates HADA's effects on renal function and structure in rats, focusing on oxidative and endoplasmic reticulum stress as potential mechanisms of renal injury.

OBJECTIVE

To elucidate the pathophysiological mechanisms of renal damage in HADA and evaluate the efficacy of antioxidants Vitamin C (Vit C) and tauroursodeoxycholic acid (TUDCA) in mitigating these effects.

METHODS

88 male Sprague-Dawley rats were randomly divided into a control group, a high-altitude (HA) group, a high-altitude de-acclimatization (HADA) group, and a treatment group. The control group was housed in a sea level environment (500 m), while the HA, HADA, and treatment groups were placed in a simulated high-altitude chamber (5000 m) for 90 days. After this period, the HA group completed the modeling phase; the HADA group was further subdivided into four subgroups, each continuing to be housed in a sea level environment for 3, 7, 14, and 30 days, respectively. The treatment group was split into the Vit C group, the TUDCA group, and two placebo groups, receiving medication for 3 consecutive days, once daily upon return to the sea level. The Vit C group received 100 mg/kg Vit C solution via intravenous injection, the TUDCA group received 250 mg/kg TUDCA solution via intraperitoneal injection, and the placebo groups received an equivalent volume of saline similarly. Serum, urine, and kidney tissues were collected immediately after the modeling phase. Renal function and oxidative stress levels were assessed using biochemical and ELISA methods. Renal histopathology was observed with H&E, Masson's trichrome, PAS, and PASM staining. Transmission electron microscopy was used to examine the ultrastructure of glomeruli and filtration barrier. TUNEL staining assessed cortical apoptosis in the kidneys. Metabolomics was employed for differential metabolite screening and pathway enrichment analysis.

RESULTS

Compared to the control and HA groups, the HADA 3-day group (HADA-3D) exhibited elevated renal function indicators, significant pathological damage, observable ultrastructural alterations including endoplasmic reticulum expansion and apoptosis. TUNEL-positive cells significantly increased, indicating heightened oxidative stress levels. Various differential metabolites were enriched in pathways related to oxidative and endoplasmic reticulum stress. Early intervention with Vit C and TUDCA markedly alleviated renal injury in HADA rats, significantly reducing the number of apoptotic cells, mitigating endoplasmic reticulum stress, and substantially lowering oxidative stress levels.

CONCLUSION

This study elucidates the pivotal roles of oxidative and endoplasmic reticulum stress in the early-stage renal injury in rats undergoing HADA. Early intervention with the Vit C and TUDCA significantly mitigates renal damage caused by HADA. These findings provide insights into the pathophysiological mechanisms of HADA and suggest potential therapeutic strategies for its future management.

Multiparameter spectral CT-based radiomics in predicting the expression of programmed death ligand 1 in non-small-cell lung cancer

AIM

To explore the value of radiomics for predicting the expression of programmed death ligand 1 (PD-L1) in non-small-cell lung cancer (NSCLC) based on multiparameter spectral computed tomography (CT) images.

MATERIALS AND METHODS

A total of 220 patients with NSCLC were enrolled retrospectively and divided into the training (n=176) and testing (n=44) cohorts. The radiomics features were extracted from the conventional CT images, mono-energy 40 keV images, iodine density (ID) maps, Z-effective maps, and electron density maps. The logistic regression (LR) and support vector machine (SVM) algorithms were employed to build models based on radiomics signatures. The prediction abilities were qualified by the area under the curve (AUC) obtained from the receiver operating characteristic (ROC) curve. Internal validation was performed on the independent testing dataset.

RESULTS

The combined model for PD-L1 ≥1%, which consisted of the radiomics score (rad-score; p<0.0001), white blood cell (WBC; p=0.027) counts, and air bronchogram (p=0.003), reached the highest performance with the AUCs of 0.873 and 0.917 in the training and testing dataset, respectively, which was better than the radiomics model with the AUCs of 0.842 and 0.886. The combined model for PD-L1 ≥50%, which consisted of rad-score (p<0.0001) and WBC counts (p=0.027), achieved the highest performance in the training and testing dataset with AUCs of 0.932 and 0.903, respectively, which was better than the radiomics model with AUCs of 0.920 and 0.892, respectively.

CONCLUSION

The radiomics model based on the multiparameter images of spectral CT can predict the expression level of PD-L1 in NSCLC. The combined model can obtain higher prediction efficiency and serves as a promising method for immunotherapy selection.

Effects of Birinapant on Proliferation and Invasion of MGC-803 Gastric Cancer Cells and Mechanism Underlying These Effects

We studied the effects of birinapant, a mimetic of the second mitochondria-derived activator of caspase (SMAC), on invasion and proliferation of MGC-803 gastric cancer cells and the molecular mechanisms underlying these processes. The expression of cellular inhibitor of apoptosis 1 (cIAP1) and TNF receptor-associated factor 3 (TRAF3) in gastric cancer cell line MGC-803 and normal gastric mucosa GES-1 cells were analyzed by Western blotting and cell immunofluorescence assay. After pretreatment of MGC-803 cells with birinapant, a Transwell invasion assay was used to evaluate the cell invasion ability. MGC-803 cells were implanted under the skin of BALB/c nude mice. The tumors were removed 10 days later and its size was measured. Protein expression of proliferating cell nuclear antigen (PCNA) in the subcutaneous tumors was analyzed by immunohistochemical method. In addition, the expression of cIAP1, TRAF3, pNF-κB, and NF-κB in control and birinapant-treated cells was compared by Western blotting and the rate of cell apoptosis was evaluated by flow cytometry. In untreated MGC-803 gastric cancer cells, the expression of cIAP1 was higher and the expression of TRAF3 was lower than in normal gastric mucosa cell line GES-1. Pretreatment with birinapant inhibited the invasion and proliferation of MGC-803 cells and promoted cell apoptosis. Birinapant also promoted the expression of TRAF3 and inhibited the expression of cIAP1 and pNF-κB in MGC-803 cells. Thus, birinapant inhibited the expression of cIAP1, prevented degradation of TRAF3, and suppressed invasion and proliferation of MGC-803 cells by promoting cell apoptosis.

[Prevalence and associated risk factors of pre-hypertension and hypertension in young and middle-aged population in Nanjing]

Objective: To investigate the prevalence and associated risk factors of pre-hypertension and hypertension in young and middle-aged population in Nanjing. Methods: Subjects of the study were those who underwent physical examination in the physical examination center of Nanjing Drum Tower Hospital from 2009 to 2016. The prevalence and risk factors of pre-hypertension and hypertension in young (aged 18-44 years old) and middle-aged people (aged 45-59 years old) were analyzed. Results: A total of 142 857 participants aged 18-59 years old were analyzed. Among them, 64 220 cases in the pre-hypertension group and 13 912 cases in the hypertension group. The prevalence of hypertension was 9.74% (12.51% in males and 5.82% in females). The prevalence of pre-hypertension was 44.95% (53.31% in males and 33.15% in females). In the middle-aged group, the prevalence of pre-hypertension and hypertension were 51.68% and 15.13%, respectively, which was higher than that in the young group (37.95% and 4.13%, respectively). The prevalence of pre-hypertension and hypertension in 2013-2016 was 45.37% and 10.65%, respectively, which was higher than that in 2009-2012(44.52% and 8.78%). In addition, the prevalence of abnormal blood glucose metabolism, abnormal blood lipid metabolism and abnormal glucose and lipid metabolism in the pre-hypertension group was higher than that in the normal blood pressure group, but lower than that in the hypertension group (P<0.001). A logistic regression analysis indicated that age, overweight or obesity, hyperglycemia, hypertriglyceridemia and hypercholesterolemia were risk factors of pre-hypertension in male. Age, overweight or obesity, hyperglycemia, hypertriglyceridemia, hypercholesterolemia and hyper-low density cholesterolemia were associated with hypertension in male and with pre-hypertension and hypertension in female. Conclusions: Middle age, overweight/obesity, elevated fasting plasma glucose, elevated triglyceride and elevated total cholesterol were risk factors of pre-hypertension and hypertension in both men and women. Intervention on the related risk factors should be conducted as early as possible.

UV response characteristics of mixed-phase MgZnO thin films with different structure distributions, high Iuv/Idark ratios, and fast speed MgZnO UV detectors with tunneling breakdown mechanisms

High-performance ultraviolet (UV) detectors with both high responses and fast speeds are hard to make on homogeneous crystal semiconductor materials. Here, the UV response characteristics of mixed-phase MgZnO thin films with different internal structure distributions are studied. The mixed-phase MgZnO-based detector with the given crystal composition has a high response at both deep UV light (96 A W-1 at 240 nm) and near UV light (80 A W-1 at 335 nm). Meanwhile, because of the quasi-tunneling breakdown mechanism within the device, the high-response UV detector also shows a fast response speed (tr = 0.11 μs) and recovery speed (td1 = 26 μs) at deep UV light, which is much faster than both low-response mixed-phase MgZnO-based UV detectors with other structure constitutions and reported high-response UV devices on homogenous crystal materials. The Idark of the device is just 4.27 pA under a 5 V bias voltage, so the signal-to-noise ratio of the device reached 23852 at 5.5 uW cm-2 235 nm UV light. The new quasi-tunneling breakdown mechanism is observed in some mixed-phase MgZnO thin films that contain both c-MgZnO and h-MgZnO parts, which introduce a high response, signal-to-noise ratio, and fast speed into mixed-phase MgZnO-based UV detectors at weak deep UV light.

[ Ⅲ ]

Objective: To compare the efficacy and safety of Changsulin^® with Lantus^® in treating patients with type 2 diabetes mellitus (T2DM). Methods: This was a phase Ⅲ, multicenter, randomized, open-label, parallel-group, active-controlled clinical trial. A total of 578 participants with T2DM inadequately controlled on oral hypoglycemic agents were randomized 3∶1 to Changsulin^® or Lantus^® treatment for 24 weeks. The efficacy measures included changes in glycosylated hemoglobin (HbA1c), fasting plasma glucose (FPG), 2h postprandial plasma glucose (2hPG), 8-point self-monitoring of blood glucose (SMBG) profiles from baseline, and proportions of subjects achieving targets of HbA1c and FPG. The safety outcomes included rates of hypoglycemia, adverse events (AEs) and anti-insulin glargine antibody. Results: After 24 weeks of treatment, mean HbAlc decreased 1.16% and 1.25%, FPG decreased 3.05 mmol/L and 2.90 mmol/L, 2hPG decreased 2.49 mmol/L and 2.38 mmol/L in Changsulin^® and in Lantus^®, respectively. No significant differences could be viewed in above parameters between the two groups (all P>0.05). There were also no significant differences between Changsulin^® and Lantus^® in 8-point SMBG profiles from baseline and proportions of subjects achieving the targets of HbA1c and FPG (all P>0.05). The rates of total hypoglycemia (38.00% and 39.01% for Changsulin^® and Lantus^®, respectively) and nocturnal hypoglycemia (17.25% and 16.31% for Changsulin^® and Lantus^®, respectively) were similar between the two groups (all P>0.05). Most of the hypoglycemia events were asymptomatic, and no severe hypoglycemia were found in both groups. No differences were observed in rates of AEs (61.77% vs.52.48%) and anti-insulin glargine antibody (after 24 weeks of treatment, 6.91% vs.3.65%) between the two groups (all P>0.05). Conclusions: Changsulin^® shows similar efficacy and safety profiles compared with Lantus^® and Changsulin^® treatment was well tolerated in patients with T2DM.

[The value of serum dehydroepiandrosterone sulfate in differential diagnosis of Cushing's syndrome]

Objective: To evaluate the changes and diagnostic value of serum dehydroepiandrosterone sulfate (DHEAS) in Cushing's syndrome (CS) with different etiologies. Methods: The study retrospectively recruited patients diagnosed as CS in Drum Tower Hospital affiliated to Nanjing University Medical School between January 2012 and June 2019, including 36 patients (8 males, 28 females, with an average age of 44 years) with Cushing disease (CD) and 64 patients (6 males, 58 females, with an average age of 39 years) with adrenal CS (ACS). Meanwhile, 97 patients diagnosed as nonfunctional adrenal adenoma (NFA) were also included as controls. Clinical characteristics, laboratory data, adrenocorticotropic hormone (ACTH), serum DHEAS level and sex-and age-adjusted DHEAS ratio of the three groups were collected. The sensitivity and specificity of DHEAS and its ratio in differential etiology diagnosis of CS were compared using receiver operating characteristic (ROC) curve analysis. Results: Compared to NFA group, ACS patients had lower DHEAS levels [0.39 (0.39, 0.63) μmol/L vs 2.96 (1.92, 4.60) μmol/L, P<0.01] and lower DHEAS ratio [0.58 (0.27, 0.98) vs 3.95 (3.08, 6.83), P<0.01]. DHEAS [6.49 (4.32, 11.63) μmol/L] and DHEAS ratio [9.17 (4.49, 15.41)] in CD patients were significantly higher compared to those in NFA and ACS patients (all P<0.01). There were 53 ACS patients (82.8%) with suppressed ACTH level (<2.2 pmol/L) and 11 patients (17.2%) with normal/high ACTH level (≥2.2 pmol/L). The level of 24 hour urine free cortisol in normal/high ACTH level group was lower than the suppressed ACTH group [(1 299±511) nmol/24 h vs (1 972±876) nmol/24 h, P=0.04]. No significant differences were found in the DHEAS and DHEAS ratio between the two groups. ROC analysis showed that the area under the curve of serum DHEAS and DHEAS ratio in diagnosing ACS from CD was 0.997 and 0.990, respectively. The optimal cut-off values for DHEAS and its ratio were 2.06 μmol/L and 2.10, respectively. The diagnostic sensitivity and specificity of DHEAS were 97.5% and 100%, and those of DHEAS ratio were 95.0% and 100%, respectively. Conclusion: There are significant differences in serum DHEAS level and DHEAS ratio between ACS and CD patients, which might be used as indicators for the identification of the two main CS etiologies, especially in the identification of ACS patients without plasma ACTH suppression from CD patients.

[Clinical features and outcomes of surgical versus conservative management in patients with subclinical Cushing's syndrome]

Objective: To examine the clinical characteristics and metabolic features of subclinical Cushing's syndrome (SCS), and determine the effects of surgical or conservative approaches on the hormone levels and metabolic comorbidities in patients with SCS, thereby providing the evidence for decision-making in SCS management. Methods: A total of 56 consecutive SCS patients were selected in Drum Tower Hospital Affiliated to Nanjing University Medical School between 2010 and 2018, with 41 patients undergoing surgical treatment and 15 patients receiving conservative therapy. Meanwhile, 56 and 68 cases of sex-and age-matched patients diagnosed as nonfunctional adrenal adenoma (NFA) and adrenal Cushing's syndrome (CS) were included respectively. Clinical characteristics of patients in different groups were compared. Hormone levels and metabolic comorbidities were also observed during follow-up. Results: There were 56 SCS patients, including 15 males and 41 females, with an age of (52.0±12.6) years. The circadian rhythms of adrenocorticotropic hormone (ACTH) and cortisol disappeared in CS and SCS groups. Compared to NFA group, patients with SCS were characterized by suppressed plasma ACTH level [2.40 (1.11, 4.33) pmol/L vs 4.23 (2.74, 6.26) pmol/L], elevated midnight cortisol level [(240±121) nmol/L vs (59±8) nmol/L] and increased cortisol level after 1 mg overnight dexamethasone suppression test [(241±130) nmol/L vs (34±12) nmol/L] (all P<0.01). The derangement of ACTH-cortisol axis was more obvious in CS patients compared to SCS patients. The prevalence of hypertension, glucose intolerance, dyslipidemia and osteopenia/osteoporosis were higher in SCS patients compared to NFA patients (75.0% vs 41.1%, 33.9% vs 12.5%, 62.5% vs 28.6%, 35.7% vs 8.9%, all P<0.05). The 24-hour urine free cortisol correlated positively with systolic blood pressure, glycated hemoglobin A1c (HbA1c) and fasting blood glucose in SCS patients (r=0.335, 0.562 and 0.463, respectively, all P<0.05). In the surgical group, body weight, body mass index (BMI) and blood pressure decreased significantly after surgery (all P<0.05). Glucose intolerance/diabetes mellitus improved in 6 of 9 patients, BMI of 4 of 11 overweight/obesity patients normalized, and hypertension in 54.5% of patients (12/22) showed improvement after surgery. However, no alterations of hormone levels and metabolic parameters were observed in conservatively-managed patients. Conclusions: Patients with SCS are characterized by mild autonomous cortisol secretion and increased risk of metabolic comorbidities. Compared with conservative management, hormone abnormalities were corrected and metabolic abnormalities were improved in some SCS patients after surgery.

[Evaluation on the effect of clinic standardized blood pressure measurement model applying to first blood pressure measurement among community population aged 35 years old and above]

Objective: To evaluate the effect of clinic standardized blood pressure measurement model (SBPM) applying to first blood pressure measurement among community population aged 35 years old and above. Methods: SBPM was implemented in the community health service center of Dapuqiao street, Huangpu district of Shanghai from June 1, 2018, and the data between June 1 and December 31, 2018 was used as the SBPM data. The first-diagnosis blood pressure measurement data in this center between June 1 and December 31, 2017 was used as the conventional measurement (CM) model data. The detection rate of elevated blood pressure under SBPM was standardized according to the gender and age distribution of subjects in CM. The equilibrium of the value distribution of the end digit of blood pressure value in different pressure-measuring models and difference of elevated blood pressure rate of subjects with different characteristics and seasons were analyzed by using the χ(2) test, and the difference of standardized elevated blood pressure rate in different pressure-measuring models was analyzed by using the U test. Results: The SBPM included 1 548 subjects and 639 (41.28%) of them were males. The CM included 2 952 inpatients and 1 196 (40.51%) of them were males. The frequency of the end digit of blood pressure in SBPM ranged from 9.04% to 10.72%, and both systolic and diastolic blood pressure showed a balanced distribution of end digit (P values were 0.996 and 0.981 respectively). The frequency of blood pressure end digital in the CM ranged from 0.37% to 67.92%, and both systolic and diastolic blood pressure showed an unbalanced distribution (both P values <0.001). The crude rate and standardized elevated blood pressure rate in SBPM were 23.19% (359/1 548) and 23.05%, which were higher than that in CM, about 7.22% (213/2 952) (both P values <0.001). The elevated blood pressure rate in SBPM in summer, autumn and winter was 18.85% (141/748), 26.72% (152/591) and 31.58% (66/209), respectively, which was higher than that in CM, about 6.28% (91/1 450), 7.20% (82/1 139) and 11.02% (40/363), respectively (all P values <0.001). Conclusion: The quality of blood pressure data and the efficiency of hypertension screening of SBPM are better than those of CM when applying to first blood pressure measurement among community population aged 35 years old and above.

[Adrenal androgen measurement for assessing the selectivity of adrenal venous sampling in primary aldosteronism]

Objective: To investigate the usefulness of adrenal androgens for assessing the selectivity of adrenal venous sampling (AVS). Methods: Between January 2010 and December 2016, 37 consecutive patients [with an average age of (47±14) years, 16 males and 21 females] with primary aldosteronism (PA) who underwent AVS were enrolled. AVS procedures were performed with the bilateral simultaneous technique without cosyntropin stimulation. Cortisol, androstenedione, dehydroepiandrosterone (DHEA), and DHEA sulfate (DHEAS) concentrations were measured in adrenal venous (AV) and peripheral venous (PV) samples, respectively. Results: The selectivity index (SI) based on androstenedione and DHEA was higher than that of cortisol (SI-left: 13.9, 13.1 vs 6.05, P=0.006, 0.035; SI-right: 30.4, 18.5 vs 11.6, P=0.028, 0.051). However, the SI based on DHEAS was lower than that of cortisol (SI-left: 1.3 vs 6.0, P=0.002; SI-right: 1.5 vs 11.6, P=0.038). Plasma androstenedione and DHEA concentrations were positively correlated with cortisol and aldosterone in AV samples (all P<0.001). Compared to cortisol, the variation ratio of AV androstenedione and DHEA was lower from t(-15) to t(0) (0.23, 0.43 vs 0.52, both P<0.05). Using the receiver operating characteristic curve, a SI ≥ 3.0 for androstenedione or DHEA provided optimal sensitivity(97.7%, 91.9%) and specificity (93.8%, 93.8%) in AVS. Conclusion: Given the greater AV/PV ratios and reduced variability compared to cortisol, the adrenal androgens androstenedione and DHEA are useful for assessing the selectivity of AVS without cosyntropin stimulation and may be superior analytes in conditions with marked variability of cortisol levels or with adrenocortical tumors co-secreting cortisol and aldosterone.

[Role of adrenal vein sampling in differential diagnosis of primary aldosteronism subtypes]

Objective: To investigate the role of adrenal vein sampling (AVS) in identifying the subtype of primary aldosteronism (PA). Methods: AVS was performed in 50 patients who were confirmed as PA between September 2010 and September 2016 in Nanjing Drum Tower Hospital. Clinical, biochemical and follow-up data were reviewed retrospectively. Bilaterally simultaneous catheterization without cosyntropin stimulation and contemporaneous cortisol measurement during AVS were used. Selectivity index (SI)≥1.5 suggested that the sample was from the adrenal vein.Lateralization index (LI) ≥2 suggested unilateral disease.Clinical data was further compared and the AVS findings were analyzed. Results: AVS was successful performed in 41 cases of 50 patients, and the success rate was 82%. According to the results of AVS and postoperative pathology, 41 cases were divided into aldosterone-producing adenoma (APA)/unilateral adrenal hyperplasia (UAH) group (24 cases) and idiopathic hyperaldosteronism (IHA) group (17 cases). Compared with IHA group, patients with APA/UAH showed longer duration of hypertension[10.0 (5.0, 13.0) y vs 4.0 (2.0, 8.0) y, P=0.046], higher proportion of hypokalemia (95.8% vs 64.7%, P=0.009). Furthermore, patients with APA/UAH demonstrated lower plasma renin activity (P=0.089), higher plasma aldosterone concentration and aldosterone to renin ratio (ARR) (both P<0.05). The diagnostic concordance between CT and adrenal vein sampling was only 48.8%(20/41). Conclusions: The application of bilaterally simultaneous catheterization and contemporaneous cortisol measurement improves success rate and diagnostic accuracy of AVS. AVS is useful in subtype diagnosis of PA with equivocal imaging findings.

Translocation breakpoints of chromosome 1 in male carriers: clinical features and implications for genetic counseling

Reciprocal translocation is closely associated with male infertility and recurrent miscarriages. Balanced reciprocal translocations associated with reproductive failures are predominantly observed on chromosome 1. Additionally, infertile male patients present a number of breakpoints throughout chromosome 1. A translocation breakpoint might interrupt the structure of an important gene, leading to male infertility. Here, we report the breakpoints on chromosome 1 translocation and the clinical features presented in carriers, to enable informed genetic counseling of these patients. Balanced reciprocal translocations were found in 1.57% of the tested patients. Among 82 patients, 23 patients (28.05%) were carriers of the chromosome 1 translocation: 12 presented pre-gestational infertility with clinical manifestations of azoospermia or oligozoospermia, while 11 patients presented gestational infertility (able to conceive but with a tendency to miscarry or give birth to a stillborn). The breakpoint at 1p22 was predominantly observed in these patients; additionally, breakpoints at 1p31.2, 1p10, and 1q25 were associated with gestational infertility. Breakpoints at 1p13, 1q12, and 1q21 were associated with pre-gestational infertility. These results suggested that breakpoints at 1p32, 1p13, and 1q21 were predominantly associated with pre-gestational infertility, while that at 1q25 was associated with gestational infertility. Chromosome 1 translocation carriers with infertility presenting as azoospermia or oligospermia should be counseled on chromosomal breakpoints and the different molecular technologies available to facilitate reproduction.

Dynamics of bouncing-versus-merging response in jet collision

A new regime of oblique jet collision, characterized by low impact inertia and jet merging through bridge formation, is observed and thereby completes the entire suite of possible jet collision outcomes of (soft) merging, bouncing, and (hard) merging with increasing inertia. These distinct regimes, together with the observed dependence of the collision outcome on the impact angle and liquid properties, are characterized through scaling analysis by considering the competing effects of impact inertia, surface tension, and viscous thinning of the interfacial air gap leading to merging.

The beneficial effect of metformin on β-cell function in non-obese Chinese subjects with newly diagnosed type 2 diabetes

AIM

Studies with metformin suggest a favourable change in β-cell function over sulphonylureas in the early course of obese type 2 diabetes mellitus (T2DM), but it remains unclear whether a similar effect is observed in non-obese individuals. Here we investigated the effects of metformin or glipizide gastrointestinal therapeutics system extended-release formulation (GITS) on β-cell function in non-obese patients with newly diagnosed T2DM.

METHODS

A total of 160 newly diagnosed patients with fasting glucose 7.0-13.0 mmol/L and body mass index <30 kg/m(2) from five centres in China were randomized to metformin or glipizide GITS for 24 weeks. Early insulin secretion [the ratio of area under the curve (AUC) of insulin to glucose during 0-30 min (InsAUC30 /GluAUC30 )] and insulin sensitivity [Matsuda index (ISIM )] were assessed during the standard meal tolerance test before and after therapy. Plasma glucagon-like peptide-1(GLP-1) and glucagon levels were also measured.

RESULTS

Metformin improved InsAUC30 /GluAUC30 significantly (from 8.1 ± 0.6 pmol/mmol to 10.7 ± 0.7 pmol/mmol, p < 0.05), comparable to results with glipizide GITS. In the metformin-treated lean (body mass index < 25 kg/m(2) ) subgroup, the increase in ISIM was not significant, but the improvement in InsAUC30 /GluAUC30 was of great magnitude. Increased GLP-1 responses during meal tolerance test and decreased fasting glucagon level were observed after metformin treatment. Correlation analysis showed that the improvement of InsAUC30 /GluAUC30 was associated with the changes in HbA1c (r = -0.374, p = 0.000), ISIM (r = 0.356, p = 0.001), and ΔGLP-10-30 (r = 0.225, p = 0.02).

CONCLUSIONS

Metformin improved β-cell function in non-obese subjects with newly diagnosed T2DM, which was partly independent of the change in insulin sensitivity in these subjects. This study provides evidence-based data to support metformin use in non-obese patients with T2DM as the first-line agent, which can improve both insulin sensitivity and β-cell function.

Association of the CD36 gene with impaired glucose tolerance, impaired fasting glucose, type-2 diabetes, and lipid metabolism in essential hypertensive patients

Essential hypertension is a common disorder that can increase the risk of type 2 diabetes (T2D). CD36 has been studied in patients with diabetes and hypertension extensively; however, few studies have focused on the relationship of the CD36 gene with impaired fasting glucose (IFG)/impaired glucose tolerance (IGT) or T2D in essential hypertension patients. To identify rs1049673 and rs1527483 in the CD36 gene conferring susceptibility to IFG/IGT and T2D, we conducted a case-control study in 1257 essential hypertension patients among the Han Chinese population (control: 676; IGT/IFG: 468; T2D: 113). We also evaluated the impact of two loci on insulin sensitivity, glucose tolerance and serum lipid. The major findings of this study were that rs1049673 was found associated with IFG/IGT and T2D in essential hypertension patients (Pco = 0.028; Pdom = 0.015). The rs1049673 G carriers showed significant higher Glu0 (βdom = 0.08 (0.01~0.16), Pdom = 0.045) and Lp(a) (βco = 0.04 (0.002~0.07), Pco = 0.041; βdom = 0.06 (0.01~0.12), Pdom = 0.032), and lower HDL by the linear regression with the adjustment for gender, age, BMI, and mean blood pressures. These findings provided evidence that the CD36 gene may play some role in the pathogenesis of IFG/IGT and T2D in essential hypertension patients.

Association of KCNJ11 with impaired glucose regulation in essential hypertension

KCNJ11 is one of the candidate genes for type 2 diabetes, confirmed by genome wide association study, but there are little data on the relationship between KCNJ11 and impaired glucose regulation in essential hypertension patients. To identify the effect of E23K and I337V in the KCNJ11 gene on susceptibility to impaired glucose regulation, we conducted a case control study in 1125 essential hypertension patients with or without impaired glucose regulation among a Han Chinese population. We also evaluated the impact of two SNPs on insulin sensitivity and glucose tolerance estimated through an oral glucose tolerance test. In our case control study, no association of E23K and I337V with impaired glucose regulation was found using any genotypic models. However, lysine carriers of E23K showed a significant association with decreased insulin (30 min) and Cederholm index, and valine carriers of I337V showed association with a lower Cederholm index. All the quantitative tests were performed by linear regression, with adjustment for gender, age, body mass index, blood pressure, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker treatment. These findings provided evidence that the KCNJ11 gene plays a role in the pathogenesis of decreased insulin sensitivity in essential hypertension patients.

SLC30A8 polymorphism and type 2 diabetes risk: evidence from 27 study groups

BACKGROUND AND AIMS

Intense research has been performed to identify the genetic risk factors in type 2 diabetes, and a single nucleotide polymorphism (SNP) in SLC30A8 (rs13266634) was reported to be associated with type 2 diabetes mellitus. However, published data on the association between SLC30A8 polymorphism and the risk of type 2 diabetes were inconsistent. Therefore, we conducted this meta-analysis to derive a more precise estimation of the relationship.

METHODS AND RESULTS

We searched PubMed through October 2009 to identify all relevant papers. Odds ratios (ORs) and 95% confidence intervals (CIs) were extracted under an additive genetic model. In the current meta-analysis, we identified a total of 27 groups including 42,609 cases and 69,564 controls. In analyses of the case-control studies by ethnicity, the results indicated that SLC30A8 polymorphism was related to elevate risks of type 2 diabetes both in Europeans (OR=1.15, 95% CI 1.11-1.18, P<0.001) and Asians (OR=1.15, 95% CI 1.11-1.19, P<0.001). Next, we separated hospital-based case-control studies from population-based case-control studies, however, there was no apparent difference between population-based case-control study groups (OR=1.15, 95% CI 1.12-1.17, P<0.001) and hospital-based case-control study groups (OR=1.16, 95% CI 1.07-1.25, P<0.001).

CONCLUSION

Our present meta-analysis provided evidence that SLC30A8 (rs13266634) C allele carriers could elevate the risk of type 2 diabetes, especially in Europeans and Asians.

Construction of Tissue-engineered Cartilage with BMP7 Gene-transfected Chondrocytes

In this study, the expression of bone morphogenetic protein-7 (BMP7) was investigated in tissue-engineered cartilage constructed using chondrocytes transfected with the BMP7 gene and that constructed using non-transfected chondrocytes after 7, 14, 21 and 28 days. The volume of the BMP7 gene-transfected tissue-engineered cartilage culture after 5–7 days was 9 × 9 × 2 mm, while that of the non-transfected tissue-engineered cartilage culture was 8 × 8 × 2 mm. Histomorphological analysis showed that both cultures comprised cartilaginous tissue. Both BMP7 mRNA and BMP7 protein were expressed in BMP7 gene-transfected cartilage culture grown in vitro for 7, 14, 21 or 28 days. The chondrocytes in the BMP7 gene-transfected cartilage culture were active, with increased mitochondria, Golgi bodies and rough endoplasmic reticulum compared with non-transfected cartilage. These results provide an ideal foundation for the study of BMP7 gene-transfected tissue-engineered cartilage transplantation in the repair of cartilaginous defects.

[Identification of genes related to cell phenotypic transition by differential display analysis]

To identify the genes that are differentially expressed during the phenotypic transition from vascular adventitial fibroblasts to myofibroblasts, the adventitial fibroblasts were cultured from rat thoracic aorta, and myofibroblasts were obtained by treatment of fibroblasts with TGF-beta1. Differential display PCR (DD-PCR) was used to screen for differentially expressed genes by comparison of mRNA extracted from the two cell populations. Bands upregulated or downregulated on DD gels were excised, reamplified, cloned and sequenced. DD results were verified by quantitative PCR and Northern blot analysis.Antisense oligonucleotide was transfected to study the effect of osteopontin on migration of AF. Differential display showed a significant difference in gene expression profile between the two cell types. A transcript that was downregulated in myofibroblasts showed high DNA sequence homology to part of the gene for NADH dehydrogenase subunit 5. An upregulated transcript showed significant sequence homology to osteopontin gene. Quantitative PCR and Northern blot analysis confirmed the DD results. Among the other differential bands detected, 4 candidate sequences showed no homology to the known genes. The AF numbers of migration were significantly decreased by use of OPN antisense oligonucleotide. This study suggests that the downregulation of gene encoding NADH dehydrogenase subunit 5 and upregulation of osteopontin gene and several other unknown genes may be involved in the phenotypic transition of adventitial fibroblasts to myofibroblats. Inhibition of the expression of OPN may play an important role in the process of vascular remodeling.

alpha-Adducin gene and essential hypertension in China

Adducin is a membrane skeletal protein that is involved in the regulation of membrane ion transport and cellular signal transduction. Essential hypertension has been linked to alpha-adducin gene locus, and association of a polymorphism of the gene has been found in some studies, but results of linkage or association studies on alpha-adducin gene are controversial among different populations. This study was designed to examine the linkage between alpha-adducin gene locus and essential hypertension and to reveal the relationship between an alpha-adducin gene polymorphism (Gly460Trp) and essential hypertension in a Chinese population. For the linkage study, one hundred and six Chinese nuclear families were recruited, including 417 hypertensive patients in all 474 individuals. Those samples were genotyped at D4S412 and D4S3038. The distances between the two microsatellite markers and the alpha-adducin gene locus are less than 3cM. Parametric, non-parametric linkage (NPL) analyses using the GENEHUNTER software were carried out. Sib transmission-dise- quilibrium test (S-TDT), as well as transmission-disequilibrium test (TDT). was also implemented with TDT/S-TDT Program 1.1. Serum levels of uric acid, creatinine, blood urea nitrogen (BUN), fasting glucose and lipids were determined as phenotypes. In an association study, 138 hypertensive and 121 normotensive subjects were genotyped at Gly460Trp of the alpha-adducin gene to examine a possible association between this polymorphism and blood pressure or other phenotypes. We fail to find the linkage between the two markers and essential hypertension by parametric, NPL analysis or TDT/S-TDT study. With the use of the simple association and the multivariate logistic regression analyses, we also fail to reveal a significant association between the Gly460Trp polymorphism in alpha-adducin gene and the blood pressure variation, or blood biochemical indices studied. The frequency of the 460Trp allele in Chinese (46-48%) is similar to that found in Japanese (54-60%) while the allele frequency is less common in Caucasian (13%-23%). These findings suggest that in our Chinese population, alpha-adducin 460Trp variant may not play an important role in the etiology of EH. And the negative results of linkage and TDT/ S-TDT further supports this conclusion.

[Strategies and methods to identify genes for complex diseases]

Genes underlie numerous human diseases and traits. Although we have witnessed a great deal of success in identifying disease-susceptible genes, the task remains challenging for most of the complex diseases. This paper reviews evidence for the role of genetic factors in complex diseases, and strategies that can potentially optimize our chance of success in identifying genes involved in complex diseases. Advances in molecular biology, particularly mapping of the human genome, statistical methods that provide more accurate models of complex patterns of inheritance, and advances in basic medical science, which have increased our understanding of disease pathophysiology, will ultimately strengthen the ability of the current generation of genetic epidemiological studies to identify the genetic basis of complex human disorders.

Diagnosis of Liddle syndrome by genetic analysis of beta and gamma subunits of epithelial sodium channel--a report of five affected family members

OBJECTIVE

To screen the gene mutation in beta and gamma subunits of the epithelial sodium channel (ENaC) of a Chinese family, some of whose members are clinically diagnosed as suffering from Liddle syndrome.

METHODS

Twelve family members were recruited to the study. Among them, two brothers had been clinically diagnosed as suffering from Liddle syndrome. Peripheral blood samples were collected from all members of the family and total genomic DNA was prepared for genetic analysis. Polymerase chain reaction (PCR) was used for amplifying the last exon of beta (codon 513-673) and gamma (codon 503-632) subunits of the ENaC gene. PCR products were purified and subjected to a direct DNA sequence analysis.

RESULTS

Genetic analysis of the beta ENaC gene revealed a missense mutation of CCC to CTC at codon 616 in four middle-aged men of the second generation and one young woman of the third generation. There was no mutation of the gamma ENaC gene in any of the individuals examined.

CONCLUSION

Through direct DNA sequencing analysis, we diagnosed the disease present in five members of a Chinese family as Liddle syndrome, and excluded it in some other young offspring suffering from the monogenic disease. Our results provide further evidence that Pro616 is a critical amino acid that has a key role in the inhibition of sodium channel activity.

Linkage of hypertension to chromosome 2q14-q23 in Chinese families

OBJECTIVES

To identify chromosome regions containing hypertension susceptibility genes in Chinese.

SUBJECTS AND METHODS

A three-stage study was carried out in Chinese siblings ascertained through outpatient clinics. In the first stage, 283 affected sib-pairs from 79 nuclear families were subjected to a genome-wide scan with 240 microsatellite marker loci. The second stage focused on chromosome 2 with additional markers resulting in an average distance of 5 cM and used an independent sample of 637 affected sib-pairs from 161 families. In the third stage, a fine-scale mapping study on the suggestive region was performed in an independent set of 777 affected sib-pairs from 106 families. Fourteen markers were used with an average distance less than 2 cM. Non-parametric linkage analyses (NPL), parametric linkage analyses and transmission-disequilibrium tests were used to assess evidence for linkage and association.

RESULTS

Three markers (D2S168 at 27.06 cM, D2S151 at 152.04 cM and D2S142 at 161.26 cM) on chromosome 2 with suggestive linkage to hypertension susceptibility genes were identified in the genome-wide scan. In stage II, the suggestive region around D2S151 and D2S142 was replicated, while the linkage around D2S168 was not. In the stage III fine-scale mapping study, multipoint linkage analyses showed LOD scores greater than 2.0 throughout a region between 157.16 cM and 162.46 cM (all P < 0.001) with a maximum peak of 2.24 (P= 0.00067) at 160.52 cM. We also observed a NPL Z-score peak of 3.27 at 157.55 cM (P= 0.00086).

CONCLUSIONS

The results of a suggestive region on chromosome 2q14-q23 (D2S112-D2S2370) were consistent between each of the three studies. Interestingly, this region overlaps a syntenic region that contains blood pressure quantitative trait loci identified in rat models of hypertension. These data suggest that the region near D2S142 and D2S151 deserves to be further screened for hypertension susceptibility genes.

[A study of ITS sequence as a molecular marker in the phylogeny of Drosophila nasuta subgroup]

A total of 1.1 kb including whole ITS (intertranscribed spacer), part of 5.8S rDNA and 2S rDNA were sequenced. The results reveal that D. pallidifrons, Taxon I and Taxon J share the same sequence, and D. albomicans and D. s. neonasuta have the other same one. Among the sequences, there were a handful of insertions, deletions and substitutions. Insertions and deletions occur mainly between outgroup and ingroups; yet only 1 insertion and 12 deletions were detected in D. niveifrons, and 1 deletion was found in D. s. sulfurigaster. Among all the substitutions in outgroup and ingroups, totally 55 transitions and 65 transvertions were detected. The value of transition transvertion is quite different to that of mitochondrial genome. We applied parsimony and NJ methods to reconstruct the phylogenetic relationships of the 7 taxa. They show that D. niveifrons is on the basis of the trees, which suggests that it be less related to the rest; D. albomicans, D. s. neonasuta, D. pallidifrons, Taxon I and Taxon J are more related. We suggested that more related topology of D. s. sulfurigaster and D. s. neonasuta due to the specific evolution of ITS, yet not meaning their real relationships. Sequence variations and phylogeny analysis reveal that the ITS may be not an informative marker to nasuta subgroup. However, secondary structure analysis by using PCFOLD 4.0 reveals that the structure of the ITS is quite conservative; the stem-loop of ITS 3'-end may be an important structure of rDNA splicing.

[Studies of the association of pathological myopia in Chinese patients with HLA alleles]

The second exons of the HLA-DQB1 genes in 55 patients with Pathological Myopia were amplified and then digested with ApaI, Bsp1286I, BsaHI, BssHII, HaeII, HaeIII, HpaII, RsaI to determinate the genotypes and the allele frequencies. Among the 16 alleles, HLA-DQB1*0201, *0301, *0303, *0401 alleles in PM patients differed significantly from that of the normal ones in the distribution of the alleles, and seemed to be the pathogenic genes (P < 0.05; AF = 0.1636, 0.1091, 0.1636, 0.1091 vs. 0.0400, 0.0300, 0.0400, 0.0200; RR = 4.2886, 3.5350, 4.2890, 5.0000); While the HLA-DQB1*0601, *0602 frequencies in PM patients were remarkably lower than that of the normal ones, which showed the property of protective genes (Pc = 0.0000, AF = 0.1182, 0.0818 vs. 0.4300, 0.3100). DQB1*05.32, *0504 and *0605 can not be detected. The association of PM with DQB1 was found for the first time in the world, which has great significance both to theoretical study and to clinical diagnosis.

Potential role of macrophage colony-stimulating factor in the proliferation of DEL cells

The replication and activation of both vascular smooth muscle cells and macrophages, which have previously entered the arterial wall, are key events in the atherosclerotic process. The importance of macrophage colony-stimulating factor (MCSF) in control of the growth/proliferation of both cell types confers to this compound a central role in the development of vascular lesions. In order to gain insight into the mechanisms of macrophage proliferation, we investigated the effect of MCSF upon the proliferation of DEL cells. DEL cells constitute a monocyte/histiocytic cell line that differentiates along a macrophage lineage following exposure to phorbol ester. DEL cells constitutively express MCSF, and its receptor MCSFR is encoded by c-fms. We examined whether MCSF might play a role in the proliferation of cultured DEL cells. [3H]Thymidine or 5-bromo-2-deoxyuridine (BrdU) incorporation was measured following the addition of recombinant MCSF or L929 cell supernatant (as a source of MCSF) to quiescent DEL cells. In DEL cells, serum-free L929 cell supernatant induced DNA synthesis in a dose-dependent manner, and such an effect could be blunted by pretreatment of L929 cell supernatant with anti-mouse MCSF antibody. In these cells, DNA synthesis could also be triggered in a dose-dependent manner by the addition of recombinant human MCSF (rh MCSF) or thrombin. These findings clearly show that MCSF influences DEL cell proliferation and suggest an autocrine loop activation. They indicate that MCSF plays an important role in the development of vascular lesions, which occur during atherosclerotic progression.

The inhibitory mechanisms of amlodipine in human vascular smooth muscle cell proliferation

The abnormal proliferation of vascular smooth muscle cells (VSMCs) is closely related to vascular diseases. There is growing evidence that calcium antagonists inhibit VSMC growth/proliferation, yet their molecular mechanisms remain to be determined. Recent reports suggest that p42/p44 mitogen-activated protein kinases (MAPKs) play an important role in cell growth and proliferation induced by growth factors. This study was designed to determine whether these MAPKs are involved in VSMC proliferation induced by basic fibroblast growth factor (bFGF) and to examine the inhibitory effect of amlodipine. Human VSMCs were obtained from inner mammary artery. p42/p44 MAPKs activity was measured by immunoblotting assay using anti-p42/p44 phospho-MAPK antibody. 1) bFGF (20 ng/ml) significantly activated p42/p44 MAPKs with a peak time of 5-15 min, which was maintained for 3 h. PD98059 (100 nM-10 microM), a specific inhibitor of MAPK kinase, inhibited bFGF-induced p42/p44 MAPKs activation in a dose-dependent manner. 2) Amlodipine (1-100 nM) dose-dependently inhibited p42/p44 MAPKs activation by bFGF. 3) Amlodipine (10 nM) could inhibit both short-term and long-term p42/p44 MAPKs activation by bFGF. Our results indicate that bFGF could activate p42/p44 MAPKs. Amlodipine, which could inhibit bFGF-induced human VSMC proliferation, inhibited both short-term and sustained p42/p44 MAPKs activation by bFGF, suggesting that bFGF-induced VSMC proliferation may be related to p42/p44 MAPKs activation, and that the antiproliferative effect of amlodipine may be related to its inhibition of p42/p44 MAPKs activation.

Association of the R485K polymorphism of the factor V gene with poor response to activated protein C and increased risk of coronary artery disease in the Chinese population

Inherited predisposition to thrombosis contributes to the initiation and progression of coronary artery disease (CAD). The present study was designed to explore the relationship between genetic variation of coagulation factor V and occurrence of CAD. A total of 141 unrelated patients with CAD and 175 healthy controls were analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) for variation detection in all 25 exons of the factor V gene. Among the study subjects, 55 CAD patients and 73 controls were evaluated at random for response to activated protein C (APC) by Coatest APC resistance test. Polymorphisms in exon 4, 10, 13 and 16 of factor V gene were documented [642G-->T(S156), 1628--> A(R485K), 4070A-->G(H1299R) and 5380G A(V1736M), respectively]. The study also identified a novel polymorphism 327A G in exon 2 which did not alter the amino acid residue. Leiden mutation (R506Q) was not detected in any of our 316 subjects. Among the five polymorphisms, the allele frequency of 1628G--> A was significantly different between the CAD patients and the controls (0.36 vs. 0.21, p < 0.05). Subjects homozygous or heterozygous for the A allele of 1628G-->A polymorphism had lower normalized APC ratios than those with the GG genotype in the CAD group (1.16+/-0.13 and 1.18+/-0.23 vs. 1.36+/-0.33, p <0.05) and in the controls, indicating that A(1628) allele was associated with a poor response to APC. We conclude that the 1628G-->A (R485K) polymorphism of factor V is associated with a poor response to APC and increased risk for CAD.

[HLA-DQ molecules associated with myasthenia gravis in Chinese patients]

Myasthenia Gravis (MG) is an autoimmune disease which is a neuromuscular disorder of autoimmune origin. MG in different races or ethnic groups has different genetic susceptibility. To search for the associations of MG in the Chinese patients with HLA-DQ molecules, PCR-RFLP method was employed for genotyping HLA-DQA1 and -DQB1 genes of MG patients and the normal Chinese. The distributions of alleles of DQA1 and DQB1 in the normal Chinese and the MG patients were listed. The DQB allele, DQB1 * 0302 was positively associated with MG (RR = 2.990, Pc = 0.0307), and a negative association was found for DQA1 * 0501 (RR = 0.4166, Pc = 0.0315). DQ haplotype DQA1 * 0301-DQB1 * 0302 was significantly increased in patients when compared to controls (RR = 7.727, Pc = 0.0109).

[Genetic polymorphism in natural populations of D. virilis]

In this paper we analysed the RFLP of mtDNA in Lanzhou (LZ) population of D. virilis. By reanalysing the RFLP data of our previous work on other natural populations of D. virilis, a phylogenetic tree was produced based on the UPGMA method. It shows three main clusters: the Northern populations (LZ QD), the East China populations (NJ, SH, NB) and the Southern population (QZ). With the mtDNA's RFLP data and the results of our former work on allozyme variation in natural populations of D. virilis, we suggest that there exists a latitudinal cline of genetic variation in natural populations of D.virilis. The mechanism for the maintenance of the observed latitudinal pattern is discussed.

The period gene: high conservation of the region coding for Thr-Gly dipeptides in the Drosophila nasuta species subgroup

In this study, the region corresponding to the Thr-Gly region of the period (per) gene in the Drosophila nasuta subgroup of species was sequenced. The results showed that this region was highly conserved in the D. nasuta subgroup. There were only nine variable sites found in this 300-bp-long region, all located in two small regions highly variable among Drosophila species. No length variation was observed either within this subgroup or in the Yunnan (YN) population of D. albomicans. The deduced amino acid sequences were identical for all 14 taxa in the D. nasuta subgroup, and a stretch of alternating Thr-Gly pairs was not observed in this subgroup. A phylogenetic tree was constructed. The clustering of some species was in general agreement with previous works, but it also raised some question on the phylogenetic relationship between the nasuta species. The data did not implicate the Thr-Gly region playing a role in behavioral isolation in this subgroup of Drosophila.

[Macrophage colony-stimulating factor production and c-fms expression in cultured rat aortic vascular smooth muscle cells]

The resulats of this study are as follows. (1) As measured by a bioassay, a macrophage colony-stimulating activity was detected in the serum-free conditioned medium of rat aortic vascular smooth muscle cells (VSMCs), which could be subdued by the addition of specific anti macrophage colony-stimulating factor (MCSF) antibody. (2) The presence of MCSF receptor was confirmed by immunocytochemistry using a specific anti c-Fms antibody. (3) The presence of mRNAs for MCSF and c-fms (which encoded MCSF receptor) was determined by Northern blot analysis. Their expressions were detectable in quiescent VSMCs and markedly increased after addition of serum. These data demonstrated for the first time the production of MCSF and the presence of MCSF receptor in cultured rat VSMCs. It is suggested that MCSF might modulate VSMCs functions via both autocrine and paracrine mechanisms. Rat VSMCs appear to be a suitable cell model for studying the cell proliferation effect of MCSF.

[Polymorphism of HLA-DQA1,-DQB1 genes in Uygur and Kazak ethnic groups and comprehensive analysis of 25 related populations]

HLA-DQA1 and -DQB1 genes were investigated in two Chinese minor natinalities, Uygur and Kazak using PCR-RFLP genotyping method. Of the 8 DQA1 alleles, DQA1 *0301 was the most common in Uygurs and Kazaks. DQA1 *0401 and *0601 were the rarest alleles in Uygurs and *0601 in Kazaks. Of the 16 DQB1 alleles tested, DQB1 *0201 and *0301 were the most frequent alleles in Uygurs and Kazaks. DQB1 *0502, *05032 and *0504 in Uygurs, *05032, *0504 and *0605 in Kazaks were absent. Neither DQA1 nor DQB1 difference was found between the two populations. From the phylogenetic tree based on the gene frequencies of HLA-DQA1 and -DQB1 in Uygur, Kazak and other 25 related ethnic groups, we suggest that Uygurs and Kazaks have a closer relationship, and they are closer to Mongoloid, not Caucasoid.

L-phenylalanine and smooth muscle cell proliferation from SHR and WKY rats

Cell growth and proliferation were evaluated in cultured vascular smooth muscle cells (VSMCs) isolated from spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) rat aortae by measuring [3H]-thymidine incorporation into newly synthesized DNA and by determining cell number, respectively. The results showed that in cultures from both rat strains (1) serum-, basic fibroblast growth factor (bFGF)- and thrombin-induced DNA synthesis were inhibited by L-phenylalanine dose-dependently; (2) L-phenylalanine inhibited cell proliferation in response to serum in a concentration-dependent manner; (3) L-phenylalanine inhibited serum-induced proto-oncogene c-fos and c-myc expression; (4) L-tyrosine, L-histidine and D-phenylalanine failed to mimic the inhibitory effect of L-phenylalanine. All these data demonstrate that L-phenylalanine could exert a direct and specific antiproliferative effect on VSMCs suggesting that such effect can account for the antihypertensive action of this amino acid observed in SHR.

Amlodipine inhibition of serum-, thrombin-, or fibroblast growth factor-induced vascular smooth-muscle cell proliferation

Atherosclerosis, like several other vascular diseases, exhibits structural and functional abnormalities resulting partially from an exaggerated proliferation of vascular smooth-muscle cells (VSMCs). Ca2+ channel blockers, such as amlodipine, have been suggested to retard or even prevent the progression of atherosclerosis. To determine the mechanisms involved in these effects, we investigated the influence of amlodipine on VSMC proliferation by using rat aortic VSMCs in culture. Amlodipine (0.1-10 microM) inhibited serum-, basic fibroblast growth factor (bFGF)-, and thrombin-induced VSMC proliferation and DNA synthesis in a concentration-dependent manner, as demonstrated by cell count and bromodeoxyuridine (BrdU)-incorporation measurements, respectively. Delayed addition of amlodipine after VSMC stimulation showed that the drug exerted its effect early in G1 phase of the cell cycle. This observation was confirmed by the finding that amlodipine did not influence DNA synthesis in VSMCs arrested to the G1/S boundary by hydroxyurea treatment. Consistent with its effects on VSMC growth/proliferation, amlodipine also decreased c-myc, c-fos, and c-jun protooncogene expression induced by serum, thrombin, or bFGF within 1 h after cell activation, as assessed by semiquantitative reverse transcriptase (RT)-polymerase chain reaction (PCR) analysis. The calcium channel agonist Bay K 8644, which counteracted the inhibition by nifedipine of bFGF-, thrombin- or serum-induced DNA synthesis, was ineffective to antagonize the inhibitory effect of amlodipine. The aforementioned effects of amlodipine were of similar amplitude, irrespective of the growth-enhancing agent used. This strongly indicates that amlodipine acts downstream of receptor activation to exert its antiproliferative action, probably early in the G1 phase of the cell cycle. Moreover, the lack of antagonistic effect between amlodipine and Bay K 8644 suggests that, in addition to its L-type Ca2+ channel inhibitory effect, amlodipine inhibits other intracellular signaling pathways. Such an interference of amlodipine with mitogenic signaling pathways might contribute to confer a blood vessel-protecting potential on amlodipine.

Pharmacologic treatment of atherosclerosis: beyond lipid-lowering therapy

Increased proliferation of intimal smooth muscle cells (SMCs), resulting in myointimal hyperplasia and luminal narrowing, is a characteristic of the early phase of atherogenesis. Since agents that reduce this process could potentially be considered as alternatives to lipid-lowering therapy in the prevention/treatment of atherosclerosis, it is of interest to elucidate the mechanisms involved in myointimal proliferation. This review focuses on the main mechanisms that control vascular SMC reactivity/proliferation with particular reference to spontaneously hypertensive rat-derived arterial cells, which exhibit exaggerated growth and hyperresponsiveness to stimuli compared with cells from normotensive Wistar-Kyoto rats. In view of the fact that overall cell reactivity is under the control of free Ca2+ ions, the beneficial effects of calcium antagonists on the prevention/treatment of atherosclerosis are discussed. In particular, the mechanisms whereby amlodipine--a vascular selective inhibitor of inward Ca2+ current carried by the L-type Ca2+ channels--can affect cell growth and exhibit antiatherogenic properties are reviewed.

Amlodipine and vascular hypertrophy

In both atherosclerosis and arterial hypertension, structural and functional abnormalities result in vascular hypertrophy that is associated with an increased ratio of vascular media thickness to lumen diameter and hyperreactivity of vascular smooth muscle cells (VSMCs), resulting in uncontrolled cell migration and growth in vivo. In culture, VSMCs isolated from the spontaneously hypertensive rat (SHR) also display exaggerated growth and/or proliferation compared to VSMCs isolated from normotensive control Wistar Kyoto (WKY) rats. In vitro studies of cultured VSMCs can therefore be used as a model to investigate the mechanisms whereby a drug such as amlodipine can exert its antihypertensive and antiatherogenic effects. The present in vitro investigations examine the mechanisms whereby amlodipine reduces VSMC growth/proliferation promoted by basic fibroblast growth factor (bFGF), a peptide growth factor likely to participate in the vascular smooth muscle hypertrophy of the SHR. VSMCs from SHR and/or WKY rat aortae were isolated, passaged, and cultured. The influence of amlodipine on VSMC growth/proliferation was studied by measuring DNA synthesis and cell number under experimental conditions, which allowed us to determine the cell cycle phase in which amlodipine exerts its effects. Amlodipine was found to inhibit growth and bFGF-induced DNA synthesis in a concentration-dependent manner. Delayed addition of amlodipine showed that the drug exerts its effect early in the G1 phase, a result that was confirmed by the finding that amlodipine could not inhibit bFGF-induced DNA synthesis in VSMCs arrested at the G1/S boundary. In comparative experiments, the inhibitory effect of amlodipine on both cell growth and DNA synthesis was found to be of similar magnitude in SHR- and WKY-derived VSMCs. It is therefore likely that by modulating cell growth/proliferation induced by bFGF, amlodipine may reduce the vascular hypertrophy of the SHR. Since amlodipine also has been found to inhibit VSMC migration, one may reasonably envisage that these characteristics are important components of the antiatherogenic properties of the drug.

Control of vascular smooth-muscle cell growth by macrophage-colony-stimulating factor

Since in several vascular diseases abnormal vascular smooth-muscle cell (VSMC) proliferation is often associated with the presence of macrophages, we examined whether macrophage-colony-stimulating factor (M-CSF) might play a role in the control of VSMC growth. VSMCs were isolated from rat aorta and maintained in culture. Using a bioassay, a macrophage-colony-stimulating activity was detected in the serum-free supernatant of VSMCs, which could be inhibited by the addition of specific anti-M-CSF antibodies. The presence of M-CSF receptor protein and of M-CSF and M-CSF receptor gene transcripts was demonstrated by immunocytochemistry, using a specific anti-c-Fms antibody and Northern blot analysis respectively. [3H]Thymidine incorporation was measured following the addition to quiescent VSMCs of various dilutions of L929 cell supernatant (as a source of M-CSF) or of recombinant M-CSF. Both exogenous M-CSF and serum-free VSMC conditioned medium promoted DNA synthesis in a concentration-dependent manner, and this effect could be abrogated by the presence of a specific anti-M-CSF antibody. Under similar experimental conditions, L929 cell supernatant modulated proto-oncogene expression, as assessed by Northern blot analysis of c-fos, c-myc, egr-1 and junB. It was further demonstrated that M-CSF could act in synergy with thrombin, platelet-derived growth factor or basic fibroblast growth factor in promoting VSMC DNA synthesis. These results support the hypothesis that M-CSF affects the growth of cultured rat VSMCs through paracrine/autocrine mechanisms. Its effects at both the macrophage and the VSMC level confer to M-CSF a central role in the development of vascular lesions that occurs during atherosclerotic progression.

Molecular mechanisms of vascular hypertrophy in the spontaneously hypertensive rat

1. In primary hypertension, an abnormally high vascular resistance can be explained in terms of alterations in vessel wall structure. Arterial cell hypertrophy and/or hyperplasia have been implicated as playing a central role in the vascular abnormalities noted in spontaneously hypertensive rats (SHR). Cultured arterial cells appear therefore as attractive models for studying in vitro the mechanisms whereby cells originating from hypertensives exhibit hyperproliferation and/or hyperresponsiveness. 2. This review summarized our present knowledge on growth and related biochemical events of cultured SHR-derived vascular smooth muscle cells or aortic adventitial fibroblasts, in response to various polypeptide growth factors and vasoactive agents. 3. Exaggerated growth response to various mitogens in cultured SHR-derived vascular cells has been well documented. However, the molecular mechanisms of abnormal growth in SHR remain unknown. This abnormality seems not to be a consequence of the alterations at the levels of receptors or of some key mitogenic events of early signalling pathways such as phospholipase C, protein kinase C and G-proteins. Further studies should therefore focus on the more distal events related to cell growth.

Mechanism of action of the inhibitory effect of nifedipine on the growth of cultured aortic cells from spontaneously hypertensive and normotensive rats

1. To gain insight into the parameters which control vascular structure, we investigated the mechanisms whereby nifedipine, and other dihydropyridines, inhibit the growth of cultured fibroblasts isolated from the adventitia of the aorta of spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats. 2. The effects of nifedipine on cell proliferation and on serum-induced DNA synthesis were determined by measuring the cell number and the incorporation of [3H]-thymidine, respectively. The mechanism of action of nifedipine was studied by adding the drug either to randomly growing cells or to quiescent, G0/G1 arrested and synchronized cells. The effects of varying the duration of drug treatment were also examined. 3. In randomly growing cultures nifedipine, like other dihydropyridines concentration-dependently inhibited cell proliferation; the rank order of effect (measured at a concentration of 10 microM) was nifedipine > nisoldipine > nitrendipine approximately nimodipine. 4. In G0/G1 arrested cell cultures, nifedipine concentration-dependently inhibited serum-induced [3H]-thymidine incorporation. In this respect it had similar effects in cell cultures from WKY and SHR. In both SHR and WKY cultures, nifedipine delayed the transition from G0/G1 to S phase, and inhibited serum-induced DNA synthesis possibly by acting on the early G1 phase. 5. In cell cultures from both SHR and WKY, serum-induced DNA synthesis was similarly (approximately 40%) inhibited after a 1 day treatment with 10 microM nifedipine. In contrast, after 5 days treatment with the drug, the inhibition of DNA synthesis was approximately 65% and approximately 10% in SHR and WKY cultures, respectively. The inhibitory effects of nifedipine against proliferation of fibroblasts were 25% and 60%, respectively,after 1 and 5 days of treatment, and were similar in cells derived from SHR and WKY. This indicates that 5 days treatment with nifedipine inhibited the proliferation of SHR and WKY fibro blasts by acting mostly on the early G1 phase and the M phase, respectively.6. Irrespective of the duration of treatment (1 or 5 days) with 10 microM nifedipine, the inhibition of DNA synthesis could be abolished and partially reduced by Bay K 8644 (1 microM) in WKY and SHR fibroblasts,respectively. In cell cultures from both SHR and WKY the inhibitory effects of a short term and of along term treatment with nifedipine against cell proliferation were reduced and unaffected, respectively by Bay K 8644.7. These results indicate that nifedipine inhibited cell proliferation and serum-induced DNA synthesis by altering the cell cycle through different mechanisms in SHR and WKY fibroblasts. They also suggest the existence in aortic fibroblasts of interactions between calcium channel blockers of the dihydropyridine series and the mitogenic signalling pathways of growth factors contained in serum.

[Mitogenic effect of erythropoietin on cultured aortic myocytes]

The administration of recombinant erythropoietin (rHuEpo) to anemic chronic renal failure patients may be associated with an increase in blood pressure, possibly by direct effects on peripheral blood vessels. In the present study, experiments were designed to explore the hypothesis that rHuEpo could enhance vascular resistance through mitogenic effect on vascular smooth muscle cells (VSMCs), and that preexisting hypertension might be a predisposing condition. Cultured VSMCs from the thoracic aortae of spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats were studied for DNA synthesis, phospholipase C activity, and cell growth related proto-oncogene expression in the presence of rHuEpo. In cells from both strains, rHuEpo dose-dependently increased DNA synthesis and stimulated phospholipase C activity, as indicated by 3H-thymidine incorporation and 3H-inositol phosphate formation, respectively (EC50 approximately 4 U/ml). Exposure of VSMCs to rHuEpo for various times gradually increased the levels of c-myc and junB and transiently induced c-fos expression, as determined by Northern analysis. rHuEpo-induced DNA synthesis was markedly enhanced in VSMCs from SHR compared to those from WKY. In contrast, rHuEpo-induced phospholipase C activity and proto-oncogene expression did not differ between the two strains. Taken together, these results suggest that rHuEpo may function as a vascular smooth muscle cell growth promoting factor through activation of the phospholipase C cascade and modulation of proto-oncogene expression. It could thereby contribute to vascular hypertrophy and arterial hypertension.

Signaling mechanisms of basic fibroblast growth factor in arterial cells from genetically hypertensive rat

The mechanisms of vascular structural alterations in hypertension were studied in cultured adventitial fibroblasts isolated from aortas of spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. Basic fibroblast growth factor (bFGF)-, epidermal growth factor (EGF)-, or platelet-derived growth factor (PDGF)-induced DNA synthesis and phospholipase C activity were estimated by determining 3H-thymidine incorporation and 3H-inositol phosphate production, respectively. The role of protein tyrosine kinases was assessed by stimulating the cells in the presence of tyrphostin, a protein tyrosine kinase inhibitor. Both the mitogenic potency of bFGF, EGF, and PDGF and the phospholipase C activity elicited by these factors were increased markedly in SHR (v WKY) fibroblasts. SHR fibroblasts were significantly less sensitive to tyrphostin inhibition of bFGF-induced 3H-thymidine incorporation than WKY fibroblasts, whereas when the cells were stimulated with EGF, PDGF, or 5% serum, SHR and WKY fibroblasts were equally sensitive to tyrphostin inhibition. At doses that abolished bFGF-induced 3H-thymidine incorporation, tyrphostin did not affect bFGF-induced 3H-inositol phosphate production. These results indicate that in aortic fibroblasts phospholipase C activation is not sufficient for bFGF-induced DNA synthesis. They suggest that tyrosine kinase activation is a necessary step in the transduction of bFGF mitogenic signal and plays an important role in the enhanced DNA synthesis exhibited by SHR (v WKY) cells. Therefore, one may envisage that bFGF contributes, through paracrine/autocrine mechanisms, to the vascular smooth muscle hyperplasia/hypertrophy in SHR.

Effect of erythropoietin on DNA synthesis, proto-oncogene expression and phospholipase C activity in rat vascular smooth muscle cells

The administration of recombinant human erythropoietin (rHuEpo) to anemic chronic renal failure patients may be associated with an increase in blood pressure, possibly by direct effects on peripheral blood vessels. The experiments of the present study were designed to explore the hypothesis that rHuEpo might exert mitogenic effects on vascular smooth muscle cells (VSMCs), and that pre-existing hypertension might be a predisposing condition. Cultured aortic VSMCs from spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats were studied for DNA synthesis, phospholipase C activity, and cell growth related proto-oncogene expression in the presence of rHuEpo. In cells from both rat strains, rHuEpo dose-dependently increased DNA synthesis and stimulated phospholipase C activity, as indicated by 3H-thymidine incorporation and inositol phosphate formation, respectively. Exposure of VSMCs to rHuEpo for various periods gradually increased the levels of c-myc and JunB mRNAs and transiently induced c-fos mRNA expression as determined by Northern analysis. The hormone-induced DNA synthesis was markedly enhanced in VSMCs from SHR compared to those from WKY. In contrast, rHuEpo-induced phospholipase C activity and proto-oncogene expression did not differ between the two strains. Taken together, these results suggest that rHuEpo may function as a vascular smooth muscle cell growth promoting factor through activation of the phospholipase C cascade and a modulation of proto-oncogene expression. It could thereby contribute to vascular hypertrophy and arterial hypertension.

Involvement of calcium channels in fibroblast growth factor-induced activation of arterial cells in spontaneously hypertensive rats

To gain insight into the mechanisms that could account for the abnormal vascular structure in spontaneously hypertensive rats (SHR) and to determine whether this could be affected by calcium channel blockers, we compared the influence of dihydropyridines on basic fibroblast growth factor (bFGF)-induced DNA synthesis in cultured adventitial fibroblasts isolated from SHR and Wistar-Kyoto rat (WKY) aorta. Our results showed that (a) bFGF was a potent mitogen for adventitial fibroblasts, much more active in SHR-derived than in WKY-derived cells, thus confirming the hyperreactivity of the SHR arterial cells; (b) the mitogenic potency of bFGF could be reduced by dihydropyridines (rank order of potency was nifedipine approximately nisoldipine > nitrendipine > nimodipine); and (c) the nifedipine inhibitory effect could be completely and partially antagonized in WKY- and SHR-derived fibroblasts, respectively, by the calcium channel agonist Bay K 8644. Moreover, the extent of nifedipine inhibitory extent increased and decreased in SHR- and WKY-derived fibroblasts, respectively, according to duration of treatment of cells with the drug, suggesting that SHR fibroblasts became progressively more sensitive whereas those of WKY became more refractory to the drug treatment. These data indicate that in aortic fibroblasts stimulated by bFGF, L-type calcium channels participate in the antimitotic effect of dihydropyridines and suggest the existence of interactions between these channels and the bFGF signaling pathways. They also suggest that nifedipine inhibits bFGF-induced DNA synthesis by different mechanisms in SHR and WKY fibroblasts.

Mitogenic events induced by vasopressin in aortic fibroblasts from spontaneously hypertensive rats

1. To further explore the mechanisms of arterial growth, we investigated the signalling pathways through which arginine-vasopressin acts as a mitogen in cultured adventitial aortic fibroblasts of the spontaneously hypertensive rat, and we examined the mechanisms involved in the hyperresponsiveness to arginine-vasopressin of fibroblasts from spontaneously hypertensive rats compared with fibroblasts from Wistar-Kyoto rats. 2. Arginine-vasopressin-induced [3H]thymidine incorporation was used to determine the peptide mitogenicity. Arginine-vasopressin-triggered hydrolysis of phosphoinositides by phospholipase C was evaluated by measuring [3H]inositol phosphate formation. The role of protein kinase C and protein tyrosine kinases in arginine-vasopressin mitogenicity was assessed by stimulating the cells with arginine-vasopressin in the presence of 12-O-tetradecanoylphorbol 13-acetate and tyrphostin (a tyrosine kinase inhibitor), respectively. 3. Arginine-vasopressin-induced DNA synthesis was completely abolished in confluent cells, whereas [3H]inositol phosphate formation was only reduced. The presence of 12-O-tetradecanoylphorbol 13-acetate markedly decreased arginine-vasopressin-induced [3H]thymidine incorporation in fibroblasts from spontaneously hypertensive rats and was without effect in fibroblasts from Wistar-Kyoto rats. Tyrphostin abolished arginine-vasopressin-induced [3H]thymidine incorporation in a dose-dependent manner and did not affect the formation of inositol phosphates. 4. These results indicate that phospholipase C activation is not sufficient for arginine-vasopressin-induced mitogenesis. They also suggest that (i) tyrosine kinase activation is a necessary step in the transduction of the arginine-vasopressin mitogenic signal, and (ii) protein kinase C participates in the increased mitogenic potency of arginine-vasopressin in spontaneously hypertensive rats.

Protein kinase C and cell proliferation in spontaneously hypertensive rats

Cultured aortic fibroblasts from spontaneously hypertensive rats (SHR) exhibit increased proliferation rate compared with cells from normotensive Wistar Kyoto (WKY) rats. The present study was designed to investigate whether this growth abnormality could be accounted for by alteration in protein kinase C (PKC). The enzyme activation by 12-O-tetradecanoyl phorbol 13-acetate (TPA) promoted 3H-thymidine incorporation which was higher in SHR-derived fibroblasts compared with WKY-derived cells. Likewise, 3H-phorbol 12,13-dibutyrate (PDBu) binding to intact cells was markedly increased in SHR-derived fibroblasts. These findings suggest a difference in PKC activity between the two cell types. In both cell types, serum-induced 3H-thymidine incorporation was enhanced by PKC down-regulation, which was obtained by prolonged treatment of cells with high dose of TPA, whereas it was inhibited in a dose-dependent manner by activation of the enzyme. The changes in serum-induced 3H-thymidine incorporation elicited either by activation or desensitization of PKC, did not differ between SHR and WKY fibroblasts. Our results indicate therefore i) that in the presence of serum PKC exerts an antiproliferative effect in rat aortic fibroblasts and ii) that the increase in PKC activity and in sensitivity to TPA exhibited by SHR-derived fibroblasts, is not involved in the increased proliferation rate displayed by SHR-derived fibroblasts in serum-containing medium.

Increased proliferation of adventitial fibroblasts from spontaneously hypertensive rat aorta

By using aortic adventitial fibroblasts in culture as a model, we first demonstrated that cells derived from spontaneously hypertensive rats (SHR), when compared with Wistar-Kyoto (WKY)-derived cells, possessed an increased capacity to proliferate and to synthesize DNA in response to vasoactive agents. At this early stage of culture, SHR fibroblasts exhibited a higher specific growth rate. Then, to gain insight into the mechanisms which could be responsible for the difference observed, signalling pathways involved in the transduction of the mitogenic signal were analysed in cells cultured for 3 days. Results indicated that, in SHR-derived fibroblasts, an increased phospholipase C activity could account for the higher mitogenic response to thrombin or vasopressin. However, this enzymatic activity, which did not differ when fibroblasts from the two rat strains were stimulated by serum, could not be responsible for the enhanced proliferation rate of SHR-derived cells. Moreover, neither protein kinase C nor pertussis toxin-sensitive G proteins appeared to contribute to the hyperresponsiveness exhibited by SHR fibroblasts. Our results indicate that the mechanism(s) responsible for such a difference vary according to the stimulus; they also suggest that adventitial fibroblasts may participate in the modified reactivity of vascular wall associated with hypertension.

[Study of mechanisms responsible for hyperproliferation of aortic cells in spontaneously hypertensive rats]

In order to determine the mechanisms which could be responsible for the hypertrophy of vascular wall associated with primary hypertension, we have investigated the mechanisms involved in the proliferation of aortic cells from spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) controls. In this study we have examined the role of phospholipase C which is responsible for the formation of second messengers, the function of protein kinase C and that of GTP-binding proteins (G proteins) which couple membrane receptors to phospholipase C. The adventitial fibroblasts from thoracic aorta were chosen as cell model in culture. The capacity of proliferation in response to 10% serum was analyzed by cell number determination and by measuring the incorporation of 3H-thymidine into newly synthesized DNA. Our results showed that SHR-derived fibroblasts proliferated more rapidly and incorporated more 3H-thymidine than WKY-derived fibroblasts. However, the phospholipase C activity, measured by the serum-stimulated production of 3H-inositol phosphates in cells prelabeled with 3H-inositol, did not differ between SHR- and WKY-derived cells. The desensitization of protein kinase C, by long term (2 d) treatment with high dose (300 nM) of phorbol 12-myristate, 13-acetate (TPA), markedly augmented, but to the same extent, the 3H-thymidine incorporation into DNA of SHR- and WKY-derived fibroblasts. Moreover, protein kinase C activation by TPA caused a parallel reduction (25-30%) of the incorporation of 3H-thymidine into DNA of SHR- and WKY-derived cells. Under the same experimental conditions, the growth of SHR- and WKY-derived fibroblasts was reduced by TPA in a dose-dependent manner (up to 20%) to the same extent.(ABSTRACT TRUNCATED AT 250 WORDS)