Breast Cancer Cells Induce a Pro-inflammatory Response to Mitigate Immune Mediation in a 3D Culture Model.

BACKGROUND: Growth factors and cytokines mediate complex interactions between cells within the breast tumour microenvironment. In advanced cancer, an excess of regulatory T (TREG) lymphocytes and lack of natural killer (NK) cells in tumour-infiltrating lymphocyte populations may reflect a shift to pro-tumorigenic adaptive immune mechanisms. To facilitate targeted assessment of the interactions between tumour and immune cells ex vivo, three-dimensional (3D) culture systems are able to better recapitulate the in vivo microenvironment, recreating the anatomy of tumours. MATERIALS AND METHODS: We used 3D breast tumour models to determine morphological alterations, and the levels of secreted transforming growth factor-ß (TGFß) and induced cytokines. 3D luminal phenotype models and basal phenotype models were generated by culturing NK cells and CD4+CD25+ TREG cells with MCF-7 cells and MDA-MB-231 cells respectively, in growth factor-reduced Matrigel. TGFß was qualitatively assessed by immunolocalisation and cytokine data from culture supernatant was acquired with a multiplex cytokine assay. Traditional statistical analysis and principal component analysis were employed to unravel the cytokine response. RESULTS AND CONCLUSION: We identified that an interleukin-6 (IL6)-chemokine axis associated with TGFß is primarily responsible for differences detected between breast cancer models, with luminal and basal phenotype tumours responding differentially to immune mediation. Identified cytokines are implicated in facilitating tumour cell subversion of immune cell function to promote an invasive phenotype. Moreover, the disruption of the extracellular matrix and failure to form well-differentiated tumour masses/networks is indicative of enhanced malignancy. Tumour cells are implicated in promoting a pro-inflammatory microenvironment to attenuate NK cell function and in inducing a pro-tumorigenic profile that is facilitated by TREG lymphocytes.

Transient Expression of Interleukin-21 in the Second Hit of Acute Pancreatitis May Potentiate Immune Paresis in Severe Acute Pancreatitis.

OBJECTIVES: Interleukin-21 (IL-21) is a cytokine associated with tissue inflammation, autoimmune and infectious diseases. Organ dysfunction and death can occur in patients with acute pancreatitis (AP) in two distinct clinical phases. Initially, a systemic inflammatory response syndrome may be followed by systemic sepsis from infected pancreatic necrosis, known as the "second hit." The expression and possible role of IL-21 in AP has not been established. METHODS: Thirty-six patients with mild, moderate, and severe AP (SAP) were enrolled. Peripheral blood samples of patients were drawn on days 7, 9, 11, and 13. Reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay were performed to determine the expression and concentration of IL-21. RESULTS: Interleukin-21 mRNA levels increased significantly at day 9 in severe (P = 0.002) pancreatitis compared with both the mild and control patient groups. At the protein level, IL-21 was elevated in SAP patients compared with those with mild pancreatitis, although this was not significant. Furthermore, day 9 IL-21 was elevated in septic SAP patients and patients with pancreatic necrosis. CONCLUSIONS: Interleukin-21 is transiently elevated in SAP compared with the mild/moderate group, and hence IL-21 may contribute to the immune imbalance that occurs in AP.

Cystatin C- and creatinine-based equations in the assessment of renal function in HIV-positive patients prior to commencing Highly Active Antiretroviral Therapy.

BACKGROUND: We evaluated the accuracy and precision of creatinine- and cystatin C-based prediction equations for estimating glomerular filtration rate compared to measured glomerular filtration rate in an antiretroviral-naive human immunodeficiency virus population. METHODS: The study population consisted of 100 treatment-naive HIV patients. Glomerular filtration rate was estimated using the Cockcroft-Gault, Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, as well as cystatin C-based equations (CKD-EPIcystatin C, cystatin Cvan Deventer and CKD-EPIcombined)) compared to (51)Cr-EDTA plasma clearance-measured glomerular filtration rate. We calculated percentage bias, standard deviation of the differences, accuracy within 15 and 30% of measured glomerular filtration rate and sensitivity and specificity for predicting measured glomerular filtration rate <60 mL/min/1.73 m(2). RESULTS: Bias for all estimating glomerular filtration rate equations ranged from -9.4% to 38.4%. The CKD-EPIcombined without ethnicity correction factor equation had the least bias, 2.9% (-2.9 to 8.8). Bias was higher for the Modification of Diet in Renal Disease and CKD-EPI equation with the African-American ethnicity factor (38.4 and 33.7%) than without (14.2 and 15.3%). Standard deviation of the differences ranged from 29.2% (CKD-EPIcombined without ethnicity factor) to 54.0% (Modification of Diet in Renal Disease with ethnicity factor). Accuracy within 30% of measured glomerular filtration rate ranged from 78% for CKD-EPIcombined without ethnicity factor to 56.7% for the Cockcroft-Gault equation. Sensitivity for creatinine-based equations was less than 50% and for the CKD-EPIcystatin C equation was 75%. CONCLUSION: Sensitivity of creatinine-based equations for predicting glomerular filtration rate was poor in this group of patients. The CKD-EPIcombined equation performed better than creatinine-based equations.

Establishment of a heterotypic 3D culture system to evaluate the interaction of TREG lymphocytes and NK cells with breast cancer.

Three-dimensional (3D) culture approaches to investigate breast tumour progression are yielding information more reminiscent of the in vivo microenvironment. We have established a 3D Matrigel system to determine the interactions of luminal phenotype MCF-7 cells and basal phenotype MDA-MB-231 cells with regulatory T lymphocytes and Natural Killer cells. Immune cells were isolated from peripheral blood using magnetic cell sorting and their phenotype validated using flow cytometry both before and after activation with IL-2 and phytohaemagglutinin. Following the establishment of the heterotypic culture system, tumour cells displayed morphologies and cell-cell associations distinct to that observed in 2D monolayer cultures, and associated with tissue remodelling and invasion processes. We found that the level of CCL4 secretion was influenced by breast cancer phenotype and immune stimulation. We further established that for RNA extraction, the use of proteinase K in conjunction with the Qiagen RNeasy Mini Kit and only off-column DNA digestion gave the best RNA yield, purity and integrity. We also investigated the efficacy of the culture system for immunolocalisation of the biomarkers oestrogen receptor-α and the glycoprotein mucin 1 in luminal phenotype breast cancer cells; and epidermal growth factor receptor in basal phenotype breast cancer cells, in formalin-fixed, paraffin-wax embedded cultures. The expression of these markers was shown to vary under immune mediation. We thus demonstrate the feasibility of using this co-culture system for downstream applications including cytokine analysis, immunolocalisation of tumour biomarkers on serial sections and RNA extraction in accordance with MIQE guidelines.

Enuresis in South African children: prevalence, associated factors and parental perception of treatment.

UNLABELLED: Study Type--Symptom Prevalence (prospective cohort) Level of Evidence 2a. What's known on the subject? and What does the study add? Nocturnal enuresis is a common childhood problem. Although its prevalence is known in many countries, no data are available from South Africa and it is difficult to extrapolate data from developed countries to a population with such diverse conditions and resource-poor settings. This study is the first to report on the 16% prevalence rate and the low level of parental knowledge of enuresis in South African children aged between 5 and 10 years. OBJECTIVES: • To establish the prevalence of NE in 5-10 year old South African children in a cross-sectional study using a parent-completed questionnaire. • To establish the parental perception and associated factors of mono-symptomatic nocturnal enuresis (MNE) treatment and treatment success rates in 5-10 year old children from South Africa. PATIENTS AND METHODS: • A total of 4700 questionnaires were distributed to children at 37 selected schools willing to participate from South Africa. Parents anonymously filled out the questionnaire. • Data were reported as frequencies and percentages of NE in tables according to different gender and age groups. • The Chi-square test compared proportions between groups and Fisher's Exact test corrected for small numbers of observations (n ≤ 5). Age differences were determined using Student's t-test. A P-value ≤ 0.5 was considered to be statistically significant. RESULTS: • The questionnaire's response rate was 72.1%, with 3389 children included in the study. • The overall prevalence of NE was 16.0%-14.4% of children suffered from mono-symptomatic NE (MNE). The prevalence of NE in boys was double that in that in girls. • Only 28.3% had received some form of treatment, whereas 13.5% had been medically treated by a doctor. Parents' awareness of treatment modalities available is outdated and most of the management of MNE was done by parents themselves, albeit with low success rates. • A positive family history was found in 50.5% of children suffering from MNE. • Constipation was a problem in 15.8% of children with enuresis. CONCLUSIONS: • This is the first study to estimate the prevalence of NE and report on the parental perception and possible associated factors of enuresis in children from South Africa. The study showed that South African children have a similar prevalence rate of NE (16%) when compared with other countries. • The possible associated factors with MNE in South Africa include constipation and a family history of enuresis. • Finally, there are low levels of parental knowledge of treatment modalities of MNE, leaving many children untreated.

Prevalence of residual left ventricular structural changes after one year of antihypertensive treatment in patients of African descent: role of 24-hour pulse pressure.

OBJECTIVES: One year of antihypertensive therapy may normalise left ventricular (LV) structure in 51% of hypertensive patients of European descent. Whether similar effects can be achieved in patients of African descent, who have a high prevalence of concentric LV hypertrophy (LVH) and remodelling, is unknown. METHODS: In 103 hypertensive patients in the Baragwanath Hypertension study we evaluated the prevalence of residual LV structural changes (echocardiography) after four and 13 months of stepwise antihypertensive therapy. RESULTS: After 13 months of therapy, 24-hour blood pressure control was achieved in 47% of patients. At baseline, 51.5% of patients had concentric LVH, 19% eccentric LVH and 12% concentric LV remodelling. Despite changes in LV mass index (p < 0.01) and relative wall thickness (p < 0.05) with treatment, the proportion of patients with a normal LV mass or geometry increased only from 17.5 to 25% (p > 0.05), while 26% remained with concentric LVH (p < 0.001 compared to baseline), 25% with eccentric LVH and 23% with concentric LV remodelling (p < 0.05 compared to baseline). Residual structural changes were associated with 24-hour pulse pressure (p = 0.02), but not with 24-hour systolic or diastolic blood pressure or clinic blood pressure. CONCLUSIONS: Even after a year of antihypertensive therapy, a high proportion (74%) of hypertensives of African ancestry retained residual LV structural changes, an effect that was associated with 24-hour pulse pressure but not systolic or diastolic blood pressures or clinic blood pressure in this ethnic group.

Modeling of cellular arginine uptake by more than one transporter.

Determining the kinetic constants of arginine uptake by endothelial cells mediated by more than one transporter from linearization of data as Eadie-Hofstee plots or modeling which does not include the concentration of trace radiolabeled amino acid used to measure uptake may not be correct. The initial rate of uptake of trace [³H]L-arginine by HUVECs and ECV304 cells in the presence of a range of unlabeled arginine and modifiers was used in nonlinear models to calculate the constants of arginine uptake using GraphPad Prism. Theoretical plots of uptake derived from constants determined from Eadie-Hofstee graphs overestimated uptake, whereas those from the nonlinear modeling approach agreed with experimental data. The contribution of uptake by individual transporters could be modeled and showed that leucine inhibited the individual transporters differently and not necessarily competitively. N-Ethylmaleimide inhibited only y⁺ transport, and BCH may be a selective inhibitor of y⁺L transport. The absence of sodium reduced arginine uptake by y⁺L transport and reduced the K(m)', whereas reducing sodium decreased arginine uptake by y⁺ transport without affecting the K (m)'. The nonlinear modeling approach using raw data avoided the errors inherent in methods deriving constants from the linearization of the uptake processes following Michaelian kinetics. This study provides explanations for discrepancies in the literature and suggests that a nonlinear modeling approach better characterizes the kinetics of amino acid uptake into cells by more than one transporter.

Lavage drain extension for local anaesthetic instillation into abdominal wounds.

BACKGROUND: A new device made by ThebeMedicare allows efficient local anaesthetic washout of wound areas, by utilising an attachment to an existing drain. The aim of this trial was to explore 'proof of concept' in patients undergoing abdominoplasty procedures. PATIENTS AND METHODS: Thirty-one patients who had undergone abdominoplasty procedures were selected for instillation of a local anaesthetic preparation, ropivacaine (Naropin, AstraZeneca) into the wound site on day 1 and 2 after surgery, followed by early mobilisation. Efficacy of the system, patient comfort and mobilisation were documented. RESULTS: The abdominoplasty patients experienced no discomfort from the procedure and claimed effective relief of pain for an average of 12 hours following instillation of local anaesthetic. All mobilised effectively. The device worked well, with no technical problems. CONCLUSION: The lavage drain extension has proved to be a cost-effective and efficient way of providing postoperative pain control and promoting early mobilisation in this patient group.

Is Degenerative Spondylolisthesis a Contraindication for Total Disc Replacement? Kineflex Lumbar Disc Replacement in 7 Patients With 24-Month Follow-up.

BACKGROUND: Degenerative spondylolisthesis is associated with a significant segmental kyphosis at the level of the listhesis. We treated 7 disc spaces with Grade 2 listhesis and/or kyphosis of the slipped disc level with Kineflex disc replacement. METHODS: Out of a single-center prospective registry, involving 310 lumbar disc replacement patients, 7 patients underwent a single-level Kineflex disc replacement at the level of a degenerative spondylolisthesis with either segmental kyphosis or a Grade 2 slip. Preoperative and follow-up radiological parameters studied were: pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis L1-S1, degree of segmental listhesis, segmental lordosis, and range of motion (ROM). Clinical outcome measures were Visual Analog Scale pain score (VAS), Oswestry Disability Index (ODI), and patient satisfaction. RESULTS: Five replacements were performed at the L4-L5 level, and 2 were performed at a L3-4 level, above a pre-existing L4-S1 posterolateral fusion. Mean age was 50 (32-62) years. Average follow-up was 23.8 ± 13.1 months. Six of 7 patients considered their outcome as good or excellent. The mean VAS score decreased from 8.4 ± 1.9 to 2.7 ± 2.2 (P < .01). The ODI decreased from 45.2 ± 9.9 preoperatively to 19.7 ± 12.8 (P < .01). There were increases in lumbar lordosis (from 47.4o ± 10.6 to 61.3o ± 8.0 (P < .03)), in segmental lordosis (from 0.17° ± 7.0° to 16.4° ± 2.0° (P < .03)), and in sacral slope (from 34.5° ± 4.8° to 40.7° ± 4.5° (P < .03)). There were decreases in pelvic tilt (from 22.6° ± 6.3° to 15.5° ± 5.9° (P < .05)), and degree of segmental listhesis (from 24.4% ± 7.7 to 3.7% ± 3.4 (P < .03)). Pelvic incidence and ROM did not change. CONCLUSIONS: Disc replacement resulted in significant improvement in clinical outcome and excellent sagittal balance and slip correction. However, the influence of improved sagittal spinal alignment on clinical outcomes needs to be investigated in larger studies including a control group. CLINICAL RELEVANCE: This study is the first focused on disc replacement in degenerative spondylolisthesis.

Lumbar disc replacement for junctional decompensation after fusion surgery: clinical and radiological outcome at an average follow-up of 33 months.

BACKGROUND: Failed fusion surgery remains difficult to treat. Few published data on disc replacement surgery after failed fusion procedures exist. Our objective was to evaluate outcomes of junctional lumbar disc replacement after previous fusion surgery and to correlate outcome with radiological changes to parameters of sagittal balance. METHODS: Out of a single-center prospective registry of 290 patients with 404 lumbar disc replacements, 27 patients had had a previous lumbar fusion operation on 1 to 4 lumbar segments and had completed a mean follow- up of 33 months (range: 18-56). We correlated the clinical outcome measures (patient satisfaction, 10-point pain score, and Oswestry Disability Index [ODI] score) to parameters of spinal sagittal alignment (sacral tilt, pelvic tilt, pelvic incidence, and lumbar lordosis). RESULTS: Postoperative hospital stay averaged 3.3 days (range: 2-8). Previously-employed patients went back to their jobs with a mean of 32 days (range: 21-42) after the procedure. At the latest follow-up, 1 of the patients considered the outcome to be poor, 3 fair, 8 good, and 15 excellent. Twenty-four patients "would undergo the operation again." Average pain score decreased from 9.1 ± 1.0 (SD) to 3.2 ± 2.1 (P < .01). Average ODI decreased from 50.2 ± 9.9 preoperatively to 21.7 ± 14.2 (P ≤ .01). We found the change in pelvic tilt to be an independent predictor of better clinical outcome by multivariate analysis (P < .05). CONCLUSIONS: In patients with junctional failure adjacent to a previous posterolateral fusion, disc replacement at the junctional level(s), compared with osteotomy and fusion surgery, offers the advantage of maintaining segmental mobility and correcting the flat-back deformity through a single approach with less operative time and blood loss. Early- to intermediate-term results are promising. The influence of changes in spinal sagittal alignment on clinical outcome needs to be addressed in future research. CLINICAL RELEVANCE: This is the first study on "junctional disc replacement patients" correlating clinical outcome to changes in spinal/pelvic alignment.

Functional variants of the angiotensinogen gene determine antihypertensive responses to angiotensin-converting enzyme inhibitors in subjects of African origin.

OBJECTIVE: To determine whether the response to angiotensin-converting enzyme inhibitor (ACEI) monotherapy in subjects of African origin is determined by genetic variants within the angiotensinogen (AGT) gene. METHODS: A total of 194 hypertensive patients of African ancestry were recruited from district clinics in Johannesburg, South Africa. Eighty patients received open-label ACEI (enalapril or lisinopril) monotherapy, and 114 open-label calcium antagonist (nifedipine) as a drug class comparator. Twenty-four hour ambulatory blood pressure (ABP) monitoring was performed at baseline (off medication) and after 2 months of therapy. DNA was analysed for functional variants (-217G-->A and -20A-->C) of the AGT gene. The impact of genotype on ABP responses to ACEI monotherapy or calcium antagonists; and on plasma aldosterone and renin levels after ACEI monotherapy was assessed. RESULTS: Adjusting for baseline ABP and type of ACEI in the ACEI-treated group, the -217G-->A variant predicted ABP responses to ACEI (n = 77; P < 0.01), but not to nifedipine (n = 108). ACEI in patients with the AA genotype of the -217G-->A variant failed to elicit an antihypertensive response [change in ABP, mmHg: systolic blood pressure (SBP) +0.84 +/- 2.89, P = 0.78; diastolic blood pressure (DBP) -0.47 +/- 1.74, P = 0.79]. In contrast, those patients with at least one copy of the -217G allele developed a 7.23 +/- 1.55 and 5.38 +/- 1.12 mmHg decrease (P < 0.0001) in SBP and DBP, respectively, after ACEI administration. Similarly, the -20A-->C variant predicted ABP responses to ACEI monotherapy (P < 0.01) but not to nifedipine. Moreover, patients who were AA genotype for both variants failed to develop an antihypertensive response to ACEI (change in ABP, mmHg: SBP +1.06 +/- 3.05, P = 0.73; DBP -0.39 +/- 1.83, P = 0.83); whereas patients with at least one copy of both the -217G and the -20C allele developed substantial decreases in ABP (change in ABP, mmHg: SBP -14.08 +/- 3.72, P < 0.0001; DBP -9.62 +/- 2.74, P < 0.0001). Patients with at least one copy of the -217G allele demonstrated a significant reduction in the aldosterone-to-renin ratio (-0.098 +/- 0.035, P < 0.01), whereas in those patients who were -217AA genotype the ratio was unchanged (-0.03 +/- 0.16, P = 0.85). CONCLUSION: Functional variants of the AGT gene contribute to the variability of antihypertensive responses to ACEI monotherapy in individuals of African ancestry, with genotype determining whether or not responses occur.

Effect of slow-release indapamide and perindopril compared with amlodipine on 24-hour blood pressure and left ventricular mass in hypertensive patients of African ancestry.

BACKGROUND: In the treatment of hypertension in subjects of African origins, although hydrochlorothiazide (HCTZ) is not as effective as calcium channel blockers, indapamide is superior to HCTZ. In the present study we therefore compared the effects of slow release (SR) indapamide with the calcium channel blocker amlodipine, when used as initial therapy, on blood pressure (BP) and left ventricular mass (LVM) during 6 months of treatment in this group. METHODS: Patients with a mean daytime ambulatory diastolic BP > or =90 mm Hg and < or =110 mm Hg (n = 125, aged 53 +/- 11 years, 68% women) were randomized to receive open-label 1.5 mg of indapamide SR or 5 mg of amlodipine. If daytime ambulatory diastolic BP at 1 month was >/=90 mm Hg, 4 mg of perindopril was added to indapamide SR or the dose of amlodipine was increased to 10 mg. RESULTS: After 1 month of therapy, there was an equivalent decline in systolic and diastolic BP in both groups (P <.0001). In the indapamide-treated group (n = 62) the daytime BP decreased from 153 +/- 12/101 +/- 6 mm Hg to 138 +/- 15/92 +/- 10 mm Hg and for amlodipine (n = 58), it decreased from 152 +/- 13/99 +/- 5 mm Hg to 138 +/- 12/91 +/- 8 mm Hg. At 6 months daytime ambulatory BP decreased to 130 +/- 15/86 +/- 8 mm Hg and to 129 +/- 11/85 +/- 5 mm Hg for the indapamide SR (n = 42) and amlodipine (n = 44) treatment groups, respectively. Both groups showed equivalent regression of LVM index and relative wall thickness. CONCLUSIONS: These data suggest that in hypertensive patients of African ancestry initiating therapy with 1.5 mg of indapamide SR and then adding 4 mg of perindopril is equally as effective as amlodipine therapy at reducing BP, and modifying target organ damage.

Impact of renin-angiotensin-aldosterone system gene variants on the severity of hypertension in patients with newly diagnosed hypertension.

BACKGROUND: The severity of hypertension has prognostic significance. Previous studies have assessed the relationship between renin-angiotensin-aldosterone system (RAAS) genotype and the severity of hypertension in either treated patients or those who have only recently discontinued treatment. METHODS: We assessed the impact of RAAS genotype on ambulatory and office blood pressure (BP) in 231 newly diagnosed hypertensive patients of African ancestry who had never received therapy. Subjects were genotyped for variants of the angiotensin-converting enzyme (insertion/deletion), angiotensinogen (M235T, -20A-->C), and aldosterone synthase (CYP11B2)(-344C-->T) genes. RESULTS: The CYP11B2 gene polymorphism was associated with systolic BP (SBP). In comparison to subjects with at least one copy of the -344C allele (n = 75), patients who were homozygous for the -344T allele (n = 156) had both higher ambulatory SBP (150 +/- 1 v 144 +/- 1 mm Hg, P =.002 before and P =.01 after adjusting for multiple genotyping) and office SBP (163 +/- 2 v 156 +/- 2 mm Hg, P =.01 before and P =.05 after adjusting for multiple genotyping). Neither the angiotensin-converting enzyme insertion/deletion nor the angiotensinogen gene polymorphisms were associated with ambulatory or office SBP or diastolic BP (DBP). The CYP11B2 gene variant also did not affect DBP. CONCLUSION: A variant within the CYP11B2 locus has a clinically important impact on the severity of SBP changes in individuals with newly diagnosed hypertension who are of African ethnicity.

Angiotensinogen gene promoter region variant modifies body size-ambulatory blood pressure relations in hypertension.

BACKGROUND: The extent to which genes modify the relationship between risk factors for hypertension and blood pressure (BP) is unclear. As angiotensinogen is expressed in adipose tissue and angiotensinogen (AGT) gene promoter variants influence the production of angiotensinogen, we evaluated the role of AGT gene variants as potential modifiers of body size-BP relations. METHODS AND RESULTS: Five hundred twenty-one hypertensives of African origin sampled from a group with a high mean body mass index (BMI) had 24-hour ambulatory BP (ABP) measurements determined off therapy and were genotyped for the AGT -6G-->A, -532C-->T, -20A-->C, and 704T-->C (M235T) gene variants. Genotypes were also determined in 547 control subjects of African origin who had a normal clinic BP. The -6A and -532C alleles were concordant with the M235T variant. Although AGT gene variants had no independent effects on either the presence of hypertension or ABP values in hypertensives, the -20A-->C polymorphism had a marked influence on the relation between ambulatory systolic BP and BMI. This relation was present in patients homozygous for the -20A allele (n=399, r=0.23, P<0.0001), but absent in those with at least one copy of the -20C allele (n=122, r=0.01, P=0.89). The M235T polymorphism did not impact on the BMI-BP relation. Specificity of the -20A-->C polymorphism effect on the BMI-BP relation is further indicated by the lack of effect on the systolic BP-age relation. CONCLUSION: An AGT gene promoter region variant is an important modifier of the relation between body size and BP. Hence, these data corroborate the notion that genetic modifiers can produce a profound impact on BP-phenotypic relations.

Comparison of indapamide and low-dose hydrochlorothiazide monotherapy in black patients with mild to moderate hypertension.

OBJECTIVES: To assess, using ambulatory blood pressure monitoring (ABPM), the antihypertensive efficacy of hydrochlorothiazide 12.5 mg and indapamide 2.5 mg given as a monotherapy over 3 months to black patients with mild to moderate essential hypertension. DESIGN: Single-centre, prospective, randomised open pilot study in three phases: (i) 1-week drug-free washout period; (ii) 2-week placebo run-in phase; and (iii) 3-month prospective open-label active treatment period. RESULTS: Forty-two black patients with mean daytime diastolic BP (DBP) > or = 90 mmHg and < or = 115 mmHg (mean age 57 +/- 11 years, 28 women/14 men) were enrolled into the study. Overall, a profound and sustained BP reduction was achieved with indapamide at 3 months (N = 20). The 24-hour BP decreased from 150 +/- 17/94 +/- 6 mmHg to 130 +/- 19/82 +/- 9 mmHg (P < 0.0001 for systolic BP (SBP) and DBP at 3 months versus baseline); the mean daytime BP decreased from 155 +/- 15/98 +/- 6 mmHg to 134 +/- 18/87 +/- 10 mmHg (P < 0.0001 for SBP and DBP at 3 months versus baseline). The overall control (mean daytime DBP < 90 mmHg) and response (decrease in daytime DBP > or = 10 mmHg) rates achieved with indapamide were 10/20 (50%) and 13/20 (65%), respectively. In contrast, monotherapy with hydrochlorothiazide resulted in more modest BP reduction and control and response rates at 3 months (N = 22). The 24-hour BP decreased from 147 +/- 14/94 +/- 7 mmHg to 139 +/- 19/88 +/- 2 mmHg (P < 0.05 for DBP at 3 months versus baseline, P = NS for SBP); the mean daytime BP decreased from 151 +/- 14/98 +/- 5 mmHg to 144 +/- 16/93 +/- 10 mmHg (P < 0.05 for DBP at 3 months versus baseline, P = NS for SBP). The corresponding control and response rates were 7/22 (32%) and 8/22 (36%). Both hydrocholorothiazide and indapamide caused significant hypokalaemia. CONCLUSIONS: Monotherapy with indapamide is associated with greater BP reduction and control and response rates than monotherapy with low-dose hydrochlorothiazide and may be an appropriate choice of antihypertensive diuretic therapy in black South African patients with mild to moderate hypertension.

Association between an atrial natriuretic peptide gene polymorphism and normal blood pressure in subjects of African ancestry.

AIM: The roles of the atrial natriuretic peptide (ANP) gene and the clearance receptor of the ANP (NPRC) gene in hypertensive groups of African ancestry are unclear. The aim of the present study was to assess the relationship between both ANP and NPRC gene polymorphisms and hypertension in Black South Africans. METHODS: 298 patients, diagnosed as having essential hypertension according to 24-hour ambulatory blood pressure (BP) measurements (mean daytime diastolic BP> 90 mm Hg) whilst off medication, and 278 normotensive control subjects of a similar African ancestry, were genotyped for polymorphic markers in intron 2 (which is in complete linkage disequilibrium with a potentially functional exon 1 variant) and exon 3 (which leads to the extension of ANP by two additional arginines) of the ANP gene. Moreover, 64 hypertensives and 63 control from the same groups were genotyped for the cis-acting promoter/enhancer element of the NPRC gene. RESULTS: No relationship between the exon 3 variant and either the presence (odds ratio = 1.075) or the severity (24-hour BP) of hypertension was noted. The intron 2 polymorphism occurred at a low frequency in the control group (frequency of subjects heterozygous for the variant = 6.1%), but was almost absent in the hypertensive group (frequency of heterozygotes = 1.7%). Consequently, a relationship between a normal BP and the intron 2 variant was noted (odds ratio = 0.28, confidence interval = 0.10-0.76, p < 0.01, <1% chance of false positive results). The NPRC gene variant occurred with an equally low frequency in both the hypertensive (4.7%) and the control (4.8%) groups. CONCLUSIONS: The results of the present study suggest that the ANP, but not the NPRC locus contributes to BP in subjects of African ancestry.

An aldosterone synthase gene variant is associated with improvement in left ventricular ejection fraction in dilated cardiomyopathy.

OBJECTIVE: To assess whether renin-angiotensin-aldosterone (RAA) system gene polymorphisms shown to be associated with alterations in the activity of the system, may predict cardiac function changes subsequent to initiating medical therapy in heart failure. METHODS: The impact of RAA system genotypes on left ventricular ejection fraction (LVEF) following therapy to patients with idiopathic dilated cardiomyopathy (IDC) and class II-III heart failure was assessed. In 107 patients LVEF and LV dimensions were determined using radionuclide ventriculography and echocardiography prior to and subsequent to receiving furosemide, digoxin and angiotensin-converting enzyme (ACE) inhibitor therapy. Patients and controls were genotyped for variants of the ACE (insertion-deletion polymorphism), angiotensinogen (AGT; M235T polymorphism) and the aldosterone synthase (CYP11B2, C-344T polymorphism) genes. RESULTS: RAA system genotypes were not significantly associated with LVEF prior to initiating medical therapy. However, the CYP11B2 gene variant (P=0.0064 on covariate analysis [adjusted for multiple genotyping] with a 1-2% chance of false positive data), but neither the ACE, nor the AGT variants, predicted improvement in LV ejection fraction in patients on medical therapy. CONCLUSION: A CYP11B2 gene variant predicts the variable improvement in LV ejection fraction that occurs subsequent to initiating medical therapy in IDC. These data suggest a role for the aldosterone synthase locus in regulating the progression of heart failure.