Challenges for malaria vector control in sub-Saharan Africa: Resistance and behavioral adaptations in Anopheles populations.

Over the past decade, global malaria-related mortality has declined dramatically because of combined international actions that have defined and prioritized national and regional efforts to reduce the incidence of malaria, with the ultimate goal of eradication. Vector control strategies using insecticide-treated nets (ITNs) and indoor residual spraying (IRS) in African countries have contributed significantly to the declining incidence of malaria. However, the effectiveness of malaria control is threatened by increasing insecticide resistance and behavioral changes in Anopheles vectors. Thus, there is an urgent need to ensure that future programmes are designed to address these threats and protect the progress made so far in controlling malaria. This review summarizes the current malaria vector control tools and discusses about the critical threats to vector control programme and vector management.

Effectiveness of Seasonal Malaria Chemoprevention in Children under Ten Years of Age in Senegal: A Stepped-Wedge Cluster-Randomised Trial.

BACKGROUND: Seasonal Malaria Chemoprevention (SMC) with sulfadoxine-pyrimethamine (SP) plus amodiaquine (AQ), given each month during the transmission season, is recommended for children living in areas of the Sahel where malaria transmission is highly seasonal. The recommendation for SMC is currently limited to children under five years of age, but, in many areas of seasonal transmission, the burden in older children may justify extending this age limit. This study was done to determine the effectiveness of SMC in Senegalese children up to ten years of age. METHODS AND FINDINGS: SMC was introduced into three districts over three years in central Senegal using a stepped-wedge cluster-randomised design. A census of the population was undertaken and a surveillance system was established to record all deaths and to record all cases of malaria seen at health facilities. A pharmacovigilance system was put in place to detect adverse drug reactions. Fifty-four health posts were randomised. Nine started implementation of SMC in 2008, 18 in 2009, and a further 18 in 2010, with 9 remaining as controls. In the first year of implementation, SMC was delivered to children aged 3-59 months; the age range was then extended for the latter two years of the study to include children up to 10 years of age. Cluster sample surveys at the end of each transmission season were done to measure coverage of SMC and the prevalence of parasitaemia and anaemia, to monitor molecular markers of drug resistance, and to measure insecticide-treated net (ITN) use. Entomological monitoring and assessment of costs of delivery in each health post and of community attitudes to SMC were also undertaken. About 780,000 treatments were administered over three years. Coverage exceeded 80% each month. Mortality, the primary endpoint, was similar in SMC and control areas (4.6 and 4.5 per 1000 respectively in children under 5 years and 1.3 and 1.2 per 1000 in children 5-9 years of age; the overall mortality rate ratio [SMC: no SMC] was 0.90, 95% CI 0.68-1.2, p = 0.496). A reduction of 60% (95% CI 54%-64%, p < 0.001) in the incidence of malaria cases confirmed by a rapid diagnostic test (RDT) and a reduction of 69% (95% CI 65%-72%, p < 0.001) in the number of treatments for malaria (confirmed and unconfirmed) was observed in children. In areas where SMC was implemented, incidence of confirmed malaria in adults and in children too old to receive SMC was reduced by 26% (95% CI 18%-33%, p < 0.001) and the total number of treatments for malaria (confirmed and unconfirmed) in these older age groups was reduced by 29% (95% CI 21%-35%, p < 0.001). One hundred and twenty-three children were admitted to hospital with a diagnosis of severe malaria, with 64 in control areas and 59 in SMC areas, showing a reduction in the incidence rate of severe disease of 45% (95% CI 5%-68%, p = 0.031). Estimates of the reduction in the prevalence of parasitaemia at the end of the transmission season in SMC areas were 68% (95% CI 35%-85%) p = 0.002 in 2008, 84% (95% CI 58%-94%, p < 0.001) in 2009, and 30% (95% CI -130%-79%, p = 0.56) in 2010. SMC was well tolerated with no serious adverse reactions attributable to SMC drugs. Vomiting was the most commonly reported mild adverse event but was reported in less than 1% of treatments. The average cost of delivery was US$0.50 per child per month, but varied widely depending on the size of the health post. Limitations included the low rate of mortality, which limited our ability to detect an effect on this endpoint. CONCLUSIONS: SMC substantially reduced the incidence of outpatient cases of malaria and of severe malaria in children, but no difference in all-cause mortality was observed. Introduction of SMC was associated with an overall reduction in malaria incidence in untreated age groups. In many areas of Africa with seasonal malaria, there is a substantial burden in older children that could be prevented by SMC. SMC in older children is well tolerated and effective and can contribute to reducing malaria transmission. TRIAL REGISTRATION: ClinicalTrials.gov NCT00712374.

Rapid and sensitive detection of genome contamination at scale with FCS-GX.

Assembled genome sequences are being generated at an exponential rate. Here we present FCS-GX, part of NCBI's Foreign Contamination Screen (FCS) tool suite, optimized to identify and remove contaminant sequences in new genomes. FCS-GX screens most genomes in 0.1-10 min. Testing FCS-GX on artificially fragmented genomes demonstrates high sensitivity and specificity for diverse contaminant species. We used FCS-GX to screen 1.6 million GenBank assemblies and identified 36.8 Gbp of contamination, comprising 0.16% of total bases, with half from 161 assemblies. We updated assemblies in NCBI RefSeq to reduce detected contamination to 0.01% of bases. FCS-GX is available at https://github.com/ncbi/fcs/ or https://doi.org/10.5281/zenodo.10651084 .

Community case management in malaria: review and perspectives after four years of operational experience in Saraya district, south-east Senegal.

BACKGROUND: Despite recent advances in malaria diagnosis and treatment, many isolated communities in rural settings continue to lack access to these life-saving tools. Community-case management of malaria (CCMm), consisting of lay health workers (LHWs) using malaria rapid diagnostic tests (RDTs) and artemisinin-based combination therapy (ACT) in their villages, can address this disparity. METHODS: This study examined routine reporting data from a CCMm programme between 2008 and 2011 in Saraya, a rural district in Senegal, and assessed its impact on timely access to rapid diagnostic tests and ACT. RESULTS: There was a seven-fold increase in the number of LHWs providing care and in the number of patients seen. LHW engagement in the CCM programme varied seasonally, 24,3% of all patients prescribed an ACT had a negative RDT or were never administered an RDT, and less than half of patients with absolute indications for referral (severe symptoms, age under two months and pregnancy) were referred. There were few stock-outs. DISCUSSION: This CCMm programme successfully increased the number of patients with access to RDT and ACT, but further investigation is required to identify the cause for over-prescription, and low rates of referrals for patients with absolute indications. In contrast, previous widespread stock-outs in Saraya's CCMm programme have now been resolved. CONCLUSION: This study demonstrates the potential for CCMm programmes to substantially increase access to life-saving malarial diagnostics and treatment, but also highlights important challenges in ensuring quality.

Rapid and sensitive detection of genome contamination at scale with FCS-GX.

Assembled genome sequences are being generated at an exponential rate. Here we present FCS-GX, part of NCBI's Foreign Contamination Screen (FCS) tool suite, optimized to identify and remove contaminant sequences in new genomes. FCS-GX screens most genomes in 0.1-10 minutes. Testing FCS-GX on artificially fragmented genomes demonstrates sensitivity >95% for diverse contaminant species and specificity >99.93%. We used FCS-GX to screen 1.6 million GenBank assemblies and identified 36.8 Gbp of contamination (0.16% of total bases), with half from 161 assemblies. We updated assemblies in NCBI RefSeq to reduce detected contamination to 0.01% of bases. FCS-GX is available at https://github.com/ncbi/fcs/.

Absence of tissue inhibitor of metalloproteinases 3 disrupts alveologenesis in the mouse.

Tissue inhibitors of metalloproteinases (TIMPs) regulate extracellular matrix (ECM) degradation by matrix metalloproteinases (MMPs) throughout lung development. We examined lungs from TIMP3 null mice and found significant air space enlargement compared with wild type (WT) animals during a time course spanning early alveologenesis (post-partum days 1, 5, 9 and 14). Trichrome staining revealed a similar pattern of collagen distribution in the walls of nascent alveoli; however, the alveolar walls of TIMP3 mutant mice appeared to be thinner than controls. Assessment of MMP2 and MMP9 activities by gelatin zymography demonstrated a significant elevation in the active form of MMP2 at post-partum days 1 and 5. Treatment of null pregnant dams with a broad spectrum synthetic metalloproteinase inhibitor, GM6001, on embryonic day 16.5 enhanced the formation of primitive alveoli during the saccular stage of lung development as evidenced by a partial, but significant, rescue of alveolar size in post-partum day 1 animals. We propose that increased MMP activity in the absence of TIMP3 enhances ECM proteolysis, upsetting proper formation of primitive alveolar septa during the saccular stage of alveologenesis. Therefore, TIMP3 indirectly regulates alveolar formation in the mouse. To our knowledge, ours is the first study to demonstrate that in utero manipulation of the TIMP/MMP proteolytic axis, to specifically inhibit proteolysis, significantly affects lung development.

Is there an association between female gender and outcome in severe trauma? A multi-center analysis in the Netherlands.

INTRODUCTION: Little evidence suggest that female gender is associated with a lower risk of mortality in severely injured patients, especially in premenopausal women. Previous clinical studies have shown contradictory results regarding protective effects of gender on outcome after severe trauma. The objective of this study was to determine the association between gender and outcome (mortality and Intensive Care Unit (ICU) admission) among severely injured patients in the Netherlands. METHODS: A retrospective multicentre study was performed including all polytrauma patients (Injury Severity Score (ISS) ≥16) admitted to the ED of three level 1 trauma centres, between January 1st, 2006 and December 31st, 2014. Data on age, gender, mechanism of injury, ISS, Abbreviated Injury Scale (AIS), prehospital intubation, Revised Trauma Score (RTS), systolic blood pressure (SBP) and Glasgow Coma Scale (GCS) upon admission at the Emergency Department was collected from three Regional Trauma Registries. To determine whether gender was an independent predictor of mortality and ICU admission, logistic regression analysis was performed. RESULTS: Among 6865 trauma patients, male patients had a significantly higher ISS compared to female patients (26.3 ± 10.2 vs 25.3 ± 9.7, P = < 0.0001). Blunt trauma was significantly more common in the female group (95.2% vs 92.3%, P = < 0.0001). Males aged 16- to 44-years had a significant higher in-hospital mortality rate (10.4% vs 13.4%, P = 0.046). ICU admission rate was significantly lower in females (49.3% vs 54.5%, P = < 0.0001). In the overall group, logistic regression did not show gender as an independent predictor for in-hospital mortality (OR 1.020 (95% CI 0.865-1.204), P = 0.811) or mortality within 24 h (OR 1.049 (95% CI 0.829-1.327), P = 0.693). However, male gender was associated with an increased likelihood for ICU admission in the overall group (OR 1.205 (95% CI 1.046-1.388), P = 0.010). CONCLUSION: The current study shows that in this population of severely injured patients, female sex is associated with a lower in-hospital mortality rate among those aged 16- to 44-years. Furthermore, female sex is independently associated with an overall decreased likelihood for ICU admission. More research is needed to examine the physiologic background of this protective effect of female sex in severe trauma.

Differential Mechanisms of Septic Human Pulmonary Microvascular Endothelial Cell Barrier Dysfunction Depending on the Presence of Neutrophils.

Sepsis is characterized by injury of pulmonary microvascular endothelial cells (PMVEC) leading to barrier dysfunction. Multiple mechanisms promote septic PMVEC barrier dysfunction, including interaction with circulating leukocytes and PMVEC apoptotic death. Our previous work demonstrated a strong correlation between septic neutrophil (PMN)-dependent PMVEC apoptosis and pulmonary microvascular albumin leak in septic mice in vivo; however, this remains uncertain in human PMVEC. Thus, we hypothesize that human PMVEC apoptosis is required for loss of PMVEC barrier function under septic conditions in vitro. To assess this hypothesis, human PMVECs cultured alone or in coculture with PMN were stimulated with PBS or cytomix (equimolar interferon γ, tumor necrosis factor α, and interleukin 1ß) in the absence or presence of a pan-caspase inhibitor, Q-VD, or specific caspase inhibitors. PMVEC barrier function was assessed by transendothelial electrical resistance (TEER), as well as fluoroisothiocyanate-labeled dextran and Evans blue-labeled albumin flux across PMVEC monolayers. PMVEC apoptosis was identified by (1) loss of cell membrane polarity (Annexin V), (2) caspase activation (FLICA), and (3) DNA fragmentation [terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)]. Septic stimulation of human PMVECs cultured alone resulted in loss of barrier function (decreased TEER and increased macromolecular flux) associated with increased apoptosis (increased Annexin V, FLICA, and TUNEL staining). In addition, treatment of septic PMVEC cultured alone with Q-VD decreased PMVEC apoptosis and prevented septic PMVEC barrier dysfunction. In septic PMN-PMVEC cocultures, there was greater trans-PMVEC macromolecular flux (both dextran and albumin) vs. PMVEC cultured alone. PMN presence also augmented septic PMVEC caspase activation (FLICA staining) vs. PMVEC cultured alone but did not affect septic PMVEC apoptosis. Importantly, pan-caspase inhibition (Q-VD treatment) completely attenuated septic PMN-dependent PMVEC barrier dysfunction. Moreover, inhibition of caspase 3, 8, or 9 in PMN-PMVEC cocultures also reduced septic PMVEC barrier dysfunction whereas inhibition of caspase 1 had no effect. Our data demonstrate that human PMVEC barrier dysfunction under septic conditions in vitro (cytomix stimulation) is clearly caspase-dependent, but the mechanism differs depending on the presence of PMN. In isolated PMVEC, apoptosis contributes to septic barrier dysfunction, whereas PMN presence enhances caspase-dependent septic PMVEC barrier dysfunction independently of PMVEC apoptosis.

The Impact of Periodic Distribution Campaigns of Long-Lasting Insecticidal-Treated Bed Nets on Malaria Vector Dynamics and Human Exposure in Dielmo, Senegal.

The implementation of long-lasting insecticidal-treated bed nets (LLINs) has contributed to halving the mortality rate due to malaria since 2000 in sub-Saharan Africa. These tools are highly effective against indoor-feeding malaria vectors. Thus, to achieve the World Health Assembly's new target to reduce the burden of malaria over the next 15 years by 90%, it is necessary to understand how the spatiotemporal dynamics of malaria vectors and human exposure to bites is modified in the context of scaling up global efforts to control malaria transmission. This study was conducted in Dielmo, a Senegalese village, after the introduction of LLINs and two rounds of LLINs renewals. Data analysis showed that implementation of LLINs correlated with a significant decrease in the biting densities of the main malaria vectors, Anopheles gambiae s.l. and Anopheles funestus, reducing malaria transmission. Other environment factors likely contributed to the decrease in An. funestus, but this trend was enhanced with the introduction of LLINs. The bulk of bites occurred during sleeping hours, but the residual vector populations of An. gambiae s.l. and An. funestus had an increased propensity to bite outdoors, so a risk of infectious bites remained for LLINs users. These results highlight the need to increase the level and correct use of LLINs and to combine this intervention with complementary control measures against residual exposure, such as spatial repellents and larval source management, to achieve the goal of eliminating malaria transmission.

Transcriptional regulation of acetyl coenzyme A carboxylase gene expression by tumor necrosis factor in 30A-5 preadipocytes.

Acetyl coenzyme A (acetyl-CoA) carboxylase activity, amount, and mRNA levels increase during the differentiation of 30A-5 preadipocytes to adipocytes. Tumor necrosis factor (TNF) completely prevents this differentiation, with concomitant inhibition of acetyl-CoA carboxylase mRNA accumulation. To investigate the mechanisms by which TNF prevents acetyl-CoA carboxylase mRNA accumulation, we determined the effect of TNF on the transcription rate of the carboxylase gene and the half-life of carboxylase mRNA. Nuclear runoff transcription assays revealed no differences in the number of RNA polymerase molecules actively engaged in transcription of the acetyl-CoA carboxylase gene in preadipocytes, adipocytes, TNF-treated preadipocytes, or at any time during the course of differentiation. However, changes in adipsin, glycerophosphate dehydrogenase, and actin mRNAs, whose levels are also differentiation dependent, can be accounted for in part by changes in the number of polymerase complexes on their respective genes. To determine whether TNF caused a decrease in the stability of carboxylase RNA transcripts, we measured the rate of decay of prelabeled acetyl-CoA carboxylase mRNA. Control and TNF-treated cells showed no difference between the apparent half-lives of acetyl-CoA carboxylase mRNAs (9 h). However, the rate of acetyl-CoA carboxylase mRNA synthesis in vivo was decreased three- to fourfold in the presence of TNF. These data demonstrate that TNF prevents accumulation of acetyl-CoA carboxylase mRNA during preadipocyte differentiation by decreasing the rate of acetyl-CoA carboxylase gene transcription. However, transcriptional control is not due to a change in the number of RNA polymerase complexes actively engaged in carboxylase transcript elongation which could be measured by a number runoff assay. Instead, transcriptional control may be related to the rate at which RNA polymerase traverses the acetyl-CoA carboxylase gene.

Long hydrocarbon chain diols and diacids with central ether or ketone moieties that favorably alter lipid disorders.

Long hydrocarbon chain derivatives with bis-terminal hydroxyl or carboxyl groups and various central moieties (ketone, ether, ester, amide, carbamate, etc.) have been synthesized and evaluated for their effects on the de novo incorporation of radiolabeled acetate into lipids in primary cultures of rat hepatocytes as well as for their effects on lipid, glycemic and body weight variables in female obese Zucker fatty rats following one and two weeks of oral administration. The most active compounds were found to be symmetrical with four to five methylene groups separating the ether or ketone central functionality from the gem dimethyl, cycloalkyl or methyl/aryl substituents. Cycloalkyl substitution alpha to the carboxyl group in keto-acids lowered the in vitro activity to micromolar values. Furthermore, in vivo biological activity was found to be greatest for cyclopropyl-substituted ketone derivatives, particularly the ketodiacid with five methylene groups on each side of the central ketone functionality, which was identified as an HDL elevator and was also found to reduce insulin and glucose.

Lack of correlation between ACAT mRNA expression and cholesterol esterification in primary liver cells.

A partial rabbit cDNA clone (14b) for ACAT has been characterized and used to demonstrate that hepatic and aortic ACAT mRNA14b abundance increased 2-3-fold in rabbits receiving a high fat/high cholesterol-diet compared to chow fed animals (Pape et al. (1995) J. Lipid Res. 36, 823-838). Because of those data we hypothesized that increased hepatic cholesteryl ester mass and synthesis rates in rabbit liver cells are associated with an increase in ACAT mRNA14b levels. To test this hypothesis we altered cellular cholesteryl ester mass and synthesis rates in primary parenchymal and nonparenchymal cells using various extracellular agents and measured the accumulated mass of ACAT mRNA14b. Parenchymal cells incubated with rabbit beta VLDL or mevalonolactone displayed a 6-10-fold increase in cellular cholesteryl ester mass over a three day treatment with no significant changes in cellular free cholesterol, triacylglycerols, or ACAT mRNA14b levels; HMG CoA reductase and LDL receptor mRNA mass decreased initially as a result of cholesteryl ester loading. Treatment of parenchymal cells with CI-976, an ACAT inhibitor, showed a marked reduction in cholesteryl ester synthetic rate compared to beta VLDL controls but displayed no change in ACAT mRNA14b levels. A mixed population of rabbit hepatic nonparenchymal cells was incubated with beta VLDL for 24 h in culture which resulted in a 6-fold increase in cellular cholesteryl ester mass; there was no change in ACAT mRNA14b levels. In an in vivo study, rabbits consuming a high fat/high cholesterol-diet for three weeks showed a 10-fold increase in hepatic cholesteryl ester with no significant changes in ACAT mRNA14b levels. Together these data indicate that rabbit liver cellular cholesteryl ester mass increases of up to 10-fold are not correlated with ACAT mRNA14b changes. Thus, hepatic ACAT mRNA14b expression and cellular cholesterol esterification do not appear to be coordinately regulated at this level of cholesteryl ester loading.

Apo B metabolism in the cynomolgus monkey: evidence for post-transcriptional regulation.

Previous studies have shown that hepatic apo B mRNA levels do not increase in animals fed high cholesterol diets, even though plasma apo B concentrations increase markedly. As a result, it has been suggested that the diet-induced increase in plasma apo B levels was due solely to an inhibited clearance of those lipoproteins. The present study was undertaken to test that hypothesis. Hepatic apo B mRNA levels were measured in liver biopsies taken from five male cynomolgus monkeys before and twice after, they began to consume a high cholesterol diet. The diet had no effect on hepatic apo B mRNA levels, even though it caused a 7-fold increase in the plasma apo B levels. However, measurements of the apo B secretion rate in eight separate monkeys (four chow-fed and four cholesterol-fed) by isotope dilution showed that apo B secretion by the liver was increased 4-fold in the cholesterol-fed monkeys. These data, taken together, indicate that apo B secretion is not regulated by the rate at which the apo B gene is transcribed, but at some point further along in the secretion pathway.

Occurrence of Bartonella henselae and Bartonella quintana among human immunodeficiency virus-infected patients.

The purpose of this study was to determine the seroprevalence against Bartonella henselae and Bartonella quintana among a risk group, patients with HIV infection, and to identify the epidemiological factors involved. Our data indicate that the prevalence of Bartonella infection among HIV-infected patients is much greater than that in the healthy population of the same area and that Bartonella infection should be considered in the differential diagnosis for patients with HIV disease.

Effect of tumor necrosis factor on acetyl-coenzyme A carboxylase gene expression and preadipocyte differentiation.

Tumor necrosis factor (TNF) is secreted by macrophages in response to various stimuli and blocks lipid accumulation during the conversion of preadipocytes to adipocytes in culture. In the present report, we investigate the effect of recombinant TNF on the expression of acetyl-coenzyme-A (CoA) carboxylase, the rate-limiting enzyme for long-chain fatty acid biosynthesis. We used a preadipocyte cell line, 30A-5, derived from 10T1/2 mouse fibroblasts after treatment with 5-azacytidine. Treatment of the preadipocyte cell line with dexamethasone and insulin triggers the conversion of these cells to mature adipocytes as evidenced by the accumulation of lipid. The mRNA and enzyme levels of acetyl-CoA carboxylase as well as the enzyme activity increase markedly during the conversion process. TNF prevents the conversion of preadipocytes to adipocytes with a concomitant inhibition in the accumulation of acetyl-CoA carboxylase mRNA and decrease in enzyme activity. This observed reduction in acetyl-CoA carboxylase mRNA levels is reversible upon removal of TNF. Acetyl-CoA carboxylase mRNA levels and enzyme activity also decrease when fully differentiated adipocytes are exposed to TNF but to a much lesser extent. These results suggest that TNF affects de novo lipid synthesis in part by altering the mRNA levels of acetyl-CoA carboxylase.

The influence of benzene on the erythroid cell system in mice.

Female BDF1 mice were exposed up to 8 weeks to airborne concentrations of 100, 300, and 900 ppm of benzene, 6 h/day, 5 days/week. The erythropoietic cell compartment in the bone marrow and the peripheral blood was studied using the erythroid burst-forming unit (BFU-E) and erythroid colony-forming unit (CFU-E) assays, the incorporation of 59Fe, and standard methods. In the peripheral blood only a slight anemia was observed. In the bone marrow, however, a considerable decrease of CFU-E numbers was seen, the CFU-E being more depressed than the BFU-E numbers. In bone marrow smears a variable content of erythroblasts was found. The 59Fe kinetics showed an enhanced turnover within the erythron, suggesting the decrease in transit time as a compensating mechanism for the low CFU-E numbers. After 4 weeks of exposure to all benzene concentrations, greater than 17 days in benzene-free atmosphere are needed for a complete recovery of BFU-E and CFU-E compartment sizes.

Demonstration of the Th1 to Th2 cytokine shift during the course of HIV-1 infection using cytoplasmic cytokine detection on single cell level by flow cytometry.

OBJECTIVE: To characterize changes of Th1/Th2 cytokine production by peripheral blood mononuclear cells (PBMC) that occur during the course of HIV infection by cytoplasmic cytokine staining on single cell level. DESIGN AND METHODS: Mitogen-stimulated PBMC from 16 healthy donors, 18 HIV-1-infected individuals without AIDS and 14 patients with AIDS were stained intracellularly with fluorescein-labelled MAb against interleukin (IL)-2, IL-4, IL-10 and interferon (IFN)-gamma. Additionally, co-staining of CD4+ T-cell, CD8+ T-cell, natural killer (NK) cell, B-cell and monocytic markers was performed. Fluorescence staining was analysed by three-colour flow-cytometry. RESULTS: A reduced percentage of IL-2 and IFN-gamma (Th1 type)-producing cells among CD4+ T cells from HIV-1-infected individuals could be demonstrated. There was a continuous decrease of IFN-gamma-producing CD4+ T cells in the course of HIV infection and a dramatic reduction of IL-2-expressing cells among CD4+ T cells in patients with AIDS. In contrast to Th1 cytokines, the frequency of Th2 cytokine expressing cells among CD4+ T cells increased in HIV-infected individuals. The maximum frequency of IL-4-expressing cells among CD4+ T cells was seen in HIV-infected individuals without AIDS, whereas the rate of IL-10-producing cells was highest in patients with AIDS. In HIV-infected individuals no significant proportion of Th0 cells expressing both Th1 and Th2 cytokines was detectable. In CD8+ T cells the percentage of IL-2 was expressing cells decreased continuously accompanied by a strong increase of the frequency of IFN-gamma-producing cells. CONCLUSION: The decreased percentage of cells expressing IL-2 and IFN-gamma in conjunction with an increased proportion of IL-4- and IL-10-producing cells among the CD4+ T cells in HIV-1-infected individuals demonstrate a Th1 to Th2 cytokine shift in the course of HIV infection on a single cell level. There was no evidence of a Th1 to Th0 cytokine shift. In addition to the loss of CD4+ T cells in HIV infection, the qualitative changes of Th1/Th2 cytokine expression may serve as a marker for progressive failure of cell-mediated immunity.

Dietary cholate increases plasma levels of apolipoprotein B in mice by posttranscriptional mechanisms.

To induce atherogenesis in mice, a high fat (HF) diet is supplemented with cholic acid (CA), which increases apoB-containing particles and lower apoA-I-containing particles. HF diet without CA increases levels of both HDL and LDL, suggesting that CA may be responsible for the elevation of LDL and lowering of HDL. The mechanism of dietary CA-induced lowering of apoA-I-containing particles has recently been reported. In this study, we examined the mechanism of CA- and HF-induced elevation of apoB-containing lipoproteins in mice. Mice were fed the following four diets: control chow (C), high fat high cholesterol, (HF), control and 0.5% cholate (CA), and HF+CA. Dietary CA increased the plasma levels of apoB-containing particles by approximately 2-fold when compared to control; VLDL levels increased 2-fold, and LDL levels increased 1.3-fold. On HF diet, VLDL increased by 1.4-fold, and LDL by 2-fold, suggesting that CA and HF-induced increases of apoB-containing particles occurred by different mechanisms. We investigated the potential mechanisms regulating plasma levels of apoB in CA- and HF-fed mice. Although hepatic apoB mRNA levels did not change on CA diet, apoB-100 mRNA increased relative to B-48 as a result of decreased editing of apoB mRNA. Measurements of hepatic LDL receptor mRNA suggested that CA diet down-regulated LDL receptor mRNA, possibly by increasing the levels of hepatic cholesterol. Since plasma and hepatic vitamin E levels did not show significant changes on CA-containing diets, it suggests that dietary CA did not act by increasing the absorption of dietary fat. Hepatic lipase, known to modulate plasma levels of apoB-containing particles, did not show changes in CA- or HF-fed mice. Taken together, these results suggest that dietary CA increased apoB-containing particles both in chow-fed and fat-fed mice by enhancing the relative production of apoB-100, and also by reducing LDL receptor-mediated clearance of apoB-containing particles. Thus, dietary cholate modulates plasma levels of apoB primarily by posttranscriptional mechanisms.

High density lipoprotein: are elevated levels desirable and achievable?

In this review we focus on addressing two questions concerning high density lipoproteins (HDL). First, are elevated levels of HDL a desirable clinical plasma endpoint and secondly, if so, can strategies be devised that would allow the identification of agents to elevate HDL. To address the first question we briefly review the human epidemiologic and prospective data that identifies HDL as a risk factor for coronary heart disease (CHD). To introduce HDL elevating strategies, we next provide a brief review of the structural and enzymatic features of HDL followed by a discussion on the current thinking of the metabolic origin of the lipoprotein. We then turn to discussions on the key plasma and cell associated proteins involved in the synthesis, catabolism, and remodeling of HDL by analyzing data derived from human mutations, genetically engineered animal models with altered HDL metabolism and in vitro experimental systems. Lastly, we propose approaches to raise HDL that are either based on identification of small organic molecules or more unconventional approaches such as gene therapy or delivery of biologicals into plasma. This last section is based on an evaluation of the putative mechanism of actions of both old and new HDL elevating compounds. Our review concludes with an optimistic view that agents can be identified which may have promise in the treatment of human hypoalphalipoproteinemia and CHD.

HMG-CoA reductase and ACAT inhibitors act synergistically to lower plasma cholesterol and limit atherosclerotic lesion development in the cholesterol-fed rabbit.

Given the beneficial effects of HMG-CoA reductase and ACAT inhibitors on hypercholesterolemia and atherosclerosis, we hypothesized that coadministration would improve the hypolipidemic response and not only limit lesion development but also alter the cellular composition of atherosclerotic lesions so as to induce a stable atherosclerotic lesion morphology. Plasma total cholesterol exposure was reduced 29 and 39% with atorvastatin (2.5 mg/kg) and CI-976 (5 mg/kg), respectively, and 60% upon coadministration due primarily to reductions in VLDL-cholesterol. Modest changes in liver cholesterol ester (CE) content were observed with atorvastatin or CI-976; however, a striking 48% reduction was noted upon coadministration. Liver HMG-CoA reductase mRNA levels were reduced 73% by cholesterol feeding and drug treatment did not prevent the reduction; however, atorvastatin alone and upon coadministration blunted the decrease in LDL receptor mRNA levels. The CE content of the iliac-femoral was unaffected by atorvastatin but was reduced 35% by CI-976 and 53% upon coadministration. Thoracic aortic CE content was reduced 38% by atorvastatin, 48% by CI-976 and 80% upon coadministration. Iliac-femoral lesion and macrophage area were reduced 48 and 67% by atorvastatin, respectively, and 68 and 81% by CI-976 but upon coadministration only an 85% reduction in macrophage area was noted. Aortic arch cross-sectional lesion and macrophage area were unaffected by atorvastatin, decreased 72-80% by CI-976 and reduced 87-92% upon coadministration. We conclude that inhibition of HMG-CoA reductase and ACAT acts synergistically to lower plasma total and lipoprotein cholesterol levels and to limit the development of atherosclerotic lesions in the cholesterol-fed rabbit by presumably regulating cholesterol trafficking pathways within liver and vascular cells.