Role of maraviroc and/or rapamycin in the liver of IL10 KO mice with frailty syndrome

Cellular senescence and low-grade inflammation favor the acceleration of aging. The liver is an essential metabolic organ because changes related to its function are related to age-related diseases. The objective of this study was to evaluate the effects of maraviroc (MVC) and/or rapamycin (RAPA) on liver tissue in an experimental model of frailty syndrome in mice, since MVC and RAPA are two molecules able to decrease CCR5 expression, which is overexpressed in patients with frailty. Methods: Eighty male homozygous IL10KO mice were randomly assigned to one of 4 groups (n = 20): i) IL10KO group; ii) MVC group, iii) RAPA group, and iv) MVC-RAPA group. Liver samples were analyzed. Gene expression quantification and western blotting were also performed. The proinflammatory cytokines IL-6 and IL-18 were decreased in MVC and MVC/RAPA groups, IL-12 was decreased in RAPA and MVC/RAPA groups and TNF-α was decreased in all therapeutic groups. P21 was decreased in RAPA and MVC/RAPA groups, Galactosidase beta-1, was also significantly reduced in all therapeutic groups, as were NF-kB1, NF-kB2 and STAT3. In all groups, mTOR and CCL5 were significantly reduced. CCR5 expression was decreased in the MVC and MVC/RAPA groups. Conclusion: MVC and RAPA may protect against some factors involved in liver aging. More studies will be necessary to verify their clinical applications.

Effectiveness and safety of integrase strand transfer inhibitors in Spain: a prospective real-world study

Introduction

Second-generation integrase strand transfer inhibitors (INSTIs) are preferred treatment options worldwide, and dolutegravir (DTG) is the treatment of choice in resource-limited settings. Nevertheless, in some resource-limited settings, these drugs are not always available. An analysis of the experience with the use of INSTIs in unselected adults living with HIV may be of help to make therapeutic decisions when second-generation INSTIs are not available. This study aimed to evaluate the real-life effectiveness and safety of dolutegravir (DTG), elvitegravir/cobicistat (EVG/c), and raltegravir (RAL) in a large Spanish cohort of HIV-1-infected patients.

Methods

Real-world study of adults living with HIV who initiated integrase INSTIs DTG, EVG/c, and RAL-based regimens in three settings (ART-naïve patients, ART-switching, and ART-salvage patients). The primary endpoint was the median time to treatment discontinuation after INSTI-based regimen initiation. Proportion of patients experiencing virological failure (VF) (defined as two consecutive viral loads (VL) ≥200 copies/mL at 24 weeks or as a single determination of VL ≥1,000 copies/mL while receiving DTG, EVG/c or RAL, and at least 3 months after INSTI initiation) and time to VF were also evaluated.

Results

Virological effectiveness of EVG/c- and RAL-based regimens was similar to that of DTG when given as first-line and salvage therapy. Treatment switching for reasons other than virological failure was more frequent in subjects receiving EVG/c and, in particular, RAL. Naïve patients with CD4+ nadir <100 cells/μL were more likely to develop VF, particularly if they initiated RAL or EVG/c. In the ART switching population, initiation of RAL and EVG/c was associated with both VF and INSTI discontinuation. There were no differences in the time to VF and INSTI discontinuation between DTG, EVG/c and RAL. Immunological parameters improved in the three groups and for the three drugs assessed. Safety and tolerability were consistent with expected safety profiles.

Discussion

Whereas second-generation INSTIs are preferred treatment options worldwide, and DTG is one of the treatment of choices in resource-limited settings, first-generation INSTIs may still provide high virological and immunological effectiveness when DTG is not available.

Kinetics of formic acid dehydration on Pt electrodes by time-resolved ATR-SEIRAS

The potential dependence of the rate of dehydration of formic acid to adsorbed CO (CO_ad) on Pt at pH 1 has been studied on a polycrystalline Pt surface by time-resolved surface-enhanced infrared absorption spectroscopy in the attenuated total reflection mode (ATR-SEIRAS) with simultaneous recording of current transients after a potential step. A range of formic acid concentrations has been used to obtain a deeper insight into the mechanism of the reaction. The experiments have allowed us to confirm that the potential dependence of the rate of dehydration has a bell shape, going through a maximum around the potential of zero total charge (pztc) of the most active site. The analysis of the integrated intensity and frequency of the bands corresponding to CO_L and CO_B/M shows a progressive population of the active sites on the surface. The observed potential dependence of the rate of formation of CO_ad is consistent with a mechanism in which the reversible electroadsorption of HCOO_ad is followed by its rate-determining reduction to CO_ad.

Use of Generic Antiretroviral Drugs and Single-Tablet Regimen De-Simplification for the Treatment of HIV Infection in Spain

The present study sought to describe the use of generic drugs and single-tablet regimen (STR) de-simplification for the treatment of human immunodeficiency virus (HIV) infection among 41 hospitals from the cohort of the Spanish HIV/AIDS Research Network (CoRIS). In June 2018, we collected information on when generic antiretroviral drugs (ARVs) were introduced in the different hospitals, how the decisions to use them were made, and how the information was provided to the patients. Most of the nine available generic ARVs in Spain by June 2018 had been introduced in at least 85% of the participating hospitals, except for zidovudine (AZT)/lamivudine (3TC) and AZT. The time difference between the effective marketing date of each generic ARV and its first dispensing date in the hospitals was much shorter for the more recently approved generic ARV since the year 2017. However, only up to 20% of the hospitals de-simplified efavirenz (EFV)/tenofovir disoproxil (TDF)/emtricitabine (FTC), dolutegravir (DTG)/abacavir (ABC)/3TC, and rilpivirine (RPV)/TDF/FTC (to generic EFV+TDF/FTC, DTG+generic ABC/3TC, and RPV+generic TDF/FTC, respectively), whereas the generic STR EFV/TDF/FTC was introduced in 87.8% of the centers. The median times between the date of effective marketing of generic TDF/FTC and the date of de-simplification of EFV/TDF/FTC and RPV/TDF/FTC were 723 [interquartile range (IQR): 369-1,119] and 234 (IQR: 142-264) days, respectively; this time was 155 (IQR: 28-287) days for de-simplification of DTG/ABC/3TC. In conclusion, despite the widespread use of generic ARVs, STRs de-simplification was only undertaken in <20% of the hospitals. There was wide variability in the timing of the introduction of each generic ARV after they were available in the market.

Elevated levels of serum CDCP1 in individuals recovering from severe COVID-19 disease

Background: COVID-19 survivors report residual lung abnormalities after discharge from the hospital. The aim of this study was to identify biomarkers in serum and induced sputum samples from patients after hospitalization for COVID-19.

Methods: Patients admitted to hospitals in Spain with laboratory-confirmed COVID-19 were recruited for this study. SARS-CoV-2-infected patients were divided into groups with mild/moderate and severe disease according to the severity of their symptoms during hospitalization. Levels of 92 biomarkers were measured in serum and induced sputum samples.

Results: A total of 108 patients (46.2% severe cases) were included in this study. The median number of days after the onset of symptoms was 104. A significant difference was observed in diffusing capacity for carbon monoxide (DLCO), an indicator of lung function, whereby DLCO <80% was significantly lower in severe cases (p <0.001). Differences in inflammatory biomarkers were observed between patients with mild/moderate and severe disease. For some biomarkers, correlations in serum and induced sputum levels were detected. Independent predictors of severe disease were DLCO <80% and the serum CDCP1 value.

Conclusions: Higher levels of CDCP1 remain after hospital discharge and are associated with the severity of COVID-19. The possible prognostic implications warrant further investigation.

HIV/HBV coinfection: temporal trends and patient characteristics, Spain, 2002 to 2018

Background

Recent and reliable estimates on the prevalence of coinfection with human immunodeficiency virus (HIV) and hepatitis B virus (HBV) in Europe are lacking.

Aim

Leveraged on a study designed to assess HIV/HCV coinfection prevalence, we assessed the prevalence of HIV/HBV coinfection in Spain in 2018 and compared the results with five similar studies performed since 2002.

Methods

This cross-sectional prevalence study was carried out in 43 centres, and patients were selected using simple random sampling. The reference population comprised 40,322 patients and the sample size were 1,690 patients.

Results

The prevalence of HIV/HBV coinfection in Spain at the end of 2018 was 3.2%. The prevalence in 2002, 2009, 2015, 2016 and 2017 was 4.9%, 3.4%, 3%, 3.9% and 3%, respectively. Among the HIV/HBV-coinfected patients identified in 2018, 16.7% had cirrhosis according to transient elastography and 26.3% tested positive for antibodies against hepatitis D virus. All HIV/HBV-coinfected patients were receiving drugs with activity against HBV, and 97% of those tested for HBV DNA had an HBV DNA load < 80 IU/mL.

Conclusions

The prevalence of HIV/HBV coinfection in Spain remained stable at around 3% for a decade. Our data could facilitate the design of national programmes to control HBV infection and help identify areas of patient management that need improvement.

Primary resistance to integrase strand transfer inhibitors in Spain using ultrasensitive HIV-1 genotyping

BACKGROUND

Transmission of resistance mutations to integrase strand transfer inhibitors (INSTIs) in HIV-infected patients may compromise the efficacy of first-line antiretroviral regimens currently recommended worldwide. Continued surveillance of transmitted drug resistance (TDR) is thus warranted.

OBJECTIVES

We evaluated the rates and effects on virological outcomes of TDR in a 96 week prospective multicentre cohort study of ART-naive HIV-1-infected subjects initiating INSTI-based ART in Spain between April 2015 and December 2016.

METHODS

Pre-ART plasma samples were genotyped for integrase, protease and reverse transcriptase resistance using Sanger population sequencing or MiSeq™ using a ≥ 20% mutant sensitivity cut-off. Those present at 1%-19% of the virus population were considered to be low-frequency variants.

RESULTS

From a total of 214 available samples, 173 (80.8%), 210 (98.1%) and 214 (100.0%) were successfully amplified for integrase, reverse transcriptase and protease genes, respectively. Using a Sanger-like cut-off, the overall prevalence of any TDR, INSTI-, NRTI-, NNRTI- and protease inhibitor (PI)-associated mutations was 13.1%, 1.7%, 3.8%, 7.1% and 0.9%, respectively. Only three (1.7%) subjects had INSTI TDR (R263K, E138K and G163R), while minority variants with integrase TDR were detected in 9.6% of subjects. There were no virological failures during 96 weeks of follow-up in subjects harbouring TDR as majority variants.

CONCLUSIONS

Transmitted INSTI resistance remains rare in Spain and, to date, is not associated with virological failure to first-line INSTI-based regimens.

Effectiveness of the combination elvitegravir/cobicistat/tenofovir/emtricitabine (EVG/COB/TFV/FTC) plus darunavir among treatment-experienced patients in clinical practice: a multicentre cohort study

BACKGROUND

The aim of this study was to investigate the effectiveness and tolerability of the combination elvitegravir/cobicistat/tenofovir/emtricitabine plus darunavir (EVG/COB/TFV/FTC + DRV) in treatment-experienced patients from the cohort of the Spanish HIV/AIDS Research Network (CoRIS).

METHODS

Treatment-experienced patients starting treatment with EVG/COB/TFV/FTC + DRV during the years 2014-2018 and with more than 24 weeks of follow-up were included. TFV could be administered either as tenofovir disoproxil fumarate or tenofovir alafenamide. We evaluated virological response, defined as viral load (VL) < 50 copies/ml and < 200 copies/ml at 24 and 48 weeks after starting this regimen, stratified by baseline VL (< 50 or ≥ 50 copies/ml at the start of the regimen).

RESULTS

We included 39 patients (12.8% women). At baseline, 10 (25.6%) patients had VL < 50 copies/ml and 29 (74.4%) had ≥ 50 copies/ml. Among patients with baseline VL < 50 copies/ml, 85.7% and 80.0% had VL < 50 copies/ml at 24 and 48 weeks, respectively, and 100% had VL < 200 copies/ml at 24 and 48 weeks. Among patients with baseline VL ≥ 50 copies/ml, 42.3% and 40.9% had VL < 50 copies/ml and 69.2% and 68.2% had VL < 200 copies/ml at 24 and 48 weeks. During the first 48 weeks, no patients changed their treatment due to toxicity, and 4 patients (all with baseline VL ≥ 50 copies/ml) changed due to virological failure.

CONCLUSIONS

EVG/COB/TFV/FTC + DRV was well tolerated and effective in treatment-experienced patients with undetectable viral load as a simplification strategy, allowing once-daily, two-pill regimen with three antiretroviral drug classes. Effectiveness was low in patients with detectable viral loads.

Implications of maraviroc and/or rapamycin in a mouse model of fragility

Background: As age increases, the risk of developing fragility also increases. Improving the knowledge of frailty could contribute to maintaining the functional ability of elderly people. Interleukin (IL)-10 homozygous knockout mice (IL-10^tm/tm [IL10KO]) constitute an excellent tool for the study of frailty. Because patients with frailty demonstrate an overexpression of CCR5, rapamycin (RAPA) and/or maraviroc (MVC), two molecules able to decrease CCR5 expression, were evaluated.

Results: Muscle myostatin was reduced in all the therapeutic groups but the MVC group (p <0.001 for RAPA and MVC-RAPA) and in serum samples (p <0.01 for all the groups). Serum CK levels were also significantly lower in MVC and RAPA groups (p <0.01 in both cases). Lower AST levels were observed in all the therapeutic groups (p <0.05 for all of them). The apoptotic effector caspase-3 was significantly lower in MVC and RAPA groups (p<0.05 in both cases). Combined treatment with MVC-RAPA showed a synergistic increase in p-AKT, p-mTOR and SIRT1 levels.

Conclusions: MVC and RAPA show a protective role in some factors involved in frailty. More studies are needed to prove their clinical applications.

Material and methods: Eighty male homozygous IL10KOs were randomly assigned to one of 4 groups (n= 20): i) IL10KO group (IL10KO); ii) IL10KO receiving MVC in drinking water (MVC group), iii) IL10KO receiving RAPA in drinking water (RAPA group), and finally, iv) MVC-RAPA group that received MVC and RAPA in drinking water. Blood and muscle samples were analysed. Survival analysis, frailty index calculation, and functional assessment were also performed.

Retinol-binding protein 4 (RBP4), a potential biomarker of frailty in HIV-infected people on stable antiretroviral therapy

OBJECTIVES

A quantitative biomarker for identification of pre-frail and frail persons is still lacking. This study aimed to identify biomarker predictors of frailty in HIV-infected patients.

METHODS

A cross-sectional study of HIV-infected patients who had been on antiretroviral therapy (ART) for at least 1 year and who presented an undetectable viral load (< 50 HIV-1 RNA copies/mL) at baseline was carried out. For each frail patient, up to four pre-frail and robust patients were randomly selected. The frailty status assessment was based on the five-item criteria described by Fried et al. Sociodemographic, anthropometric, biochemical and HIV-related characteristics were evaluated. Multiple potential biomarkers of frailty and a biological age biomarker were analysed.

RESULTS

A total of 73 HIV-infected patients on ART for at least 1 year were evaluated. The patients were categorized as robust (n = 33), pre-frail (n = 32) and frail (n = 8) using the Fried criteria. All patients were on ART, with 100% undetectable viral load (< 50 copies/mL) at baseline. No significant differences in demographic, clinical or analytical characteristics were observed among patients in the different categories based on Fried criteria, with the exception of the veterans aging cohort study index (VACS). Similarly, no differences were observed in HIV-related characteristics, although nucleoside reverse transcriptase inhibitor (NRTI) use was less common in frail persons. The distribution of biomarker values varied according to frailty status, with frail persons having higher levels of interleukin (IL)-8, IL-18, CXC chemokine ligand 10 (CXCL10) and retinol-binding protein 4 (RBP4). In multivariable analysis, the assocation of frailty with RBP4 showed a tendency to statistical significance (odds ratio 1.0; 95% confidence interval 0.99-1.00; P < 0.05).

CONCLUSIONS

Differential biomarker expression was present according to Fried status. Longitudinal studies will clarify the utility of these biomarkers as targets for diagnostic or therapeutic intervention.

The beneficial effect of probiotics as a supplementary treatment in drug-resistant epilepsy: a pilot study

Epilepsy is a neurological disease with high global prevalence. Despite the range of drug-based treatments currently available to control the condition, one in 3 patients experiences epileptic seizures. Therapeutic alternatives for these patients include the ketogenic diet, surgery or the cerebral implantation of neurostimulators; however these are benefits with limits. The target of this study is to find a new complementary treatment for these patients, studying the effectiveness of probiotics for controlling epileptic seizures in patients with drug-resistant epilepsy. A prospective study was designed in which a group of patients with drug-resistant epilepsy was administered a probiotic mixture for 4 months. Patients were assessed before and after taking the probiotics; among other variables, number of seizures and patients' quality of life (QOLIE-10) were monitored. Levels of cD-14, interleukin 6, and γ-aminobutyric acid were also analysed throughout the study. 45 patients were included in the study. In an intention-to-treat analysis, 28.9% of all patients displayed a greater than 50% reduction in the number of seizures (the parameter required in clinical trials). A significant improvement was also observed in patients' quality of life. We found that probiotics may be an option for supplementary therapy. Since the use of probiotics is safe, they may contribute to improving seizure control, and therefore quality of life, in patients with drug-resistant epilepsy. The study has been registered in https://clinicaltrials.gov with number NCT03403907.

Maraviroc improves hepatic triglyceride content but not inflammation in a murine nonalcoholic fatty liver disease model induced by a chronic exposure to high-fat diet

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the general population. Its severity ranges from simple steatosis to cirrhosis. C-C chemokine ligand type 5 or RANTES (Regulated upon Activation, Normal T-cell Expressed, and Secreted) plays an important role in the progression of hepatic inflammation and fibrosis. Our objective was to examine the preventive and therapeutic effects of maraviroc (MVC), a C-C chemokine receptor 5 antagonist, on liver pathology in an NAFLD mouse model. A total of 60 male C57BL/6 mice were randomly assigned to 1 of 4 groups: (1) high-fat diet (HFD) group or control group, (2) preventive group (HFD group plus MVC in drinking water since the beginning of the study), (3) early-therapeutic group (HFD group plus MVC in drinking starting at week 24 of the study), and (4) late-therapeutic group (HFD group plus MVC in drinking water starting at week 36 of the study). All mice were sacrificed at week 48. The hepatic triglyceride concentration in the HFD group was significantly higher than that in the groups treated with MVC at any time. Gene expression associated with lipogenesis (diacylglycerol acyltransferase 2 and proliferator-activated receptor-γ), insulin resistance (insulin receptor substrate-2), and β-oxidation (carnitine palmitoyltransferase 1A and acyl-CoA oxidase) was significantly reduced in all the groups treated with MVC. In summary, the beneficial effect of MVC on hepatic steatosis is maintained throughout the study.

Human Immunodeficiency Virus/Hepatits C Virus Coinfection in Spain: Elimination Is Feasible, but the Burden of Residual Cirrhosis Will Be Significant

Background

We assessed the prevalence of antibodies against hepatitis C virus (HCV-Abs) and active HCV infection in patients infected with human immunodeficiency virus (HIV) in Spain in 2016 and compared the results with those of similar studies performed in 2002, 2009, and 2015.

Methods

The study was performed in 43 centers during October-November 2016. The sample was estimated for an accuracy of 2% and selected by proportional allocation and simple random sampling. During 2016, criteria for therapy based on direct-acting antiviral agents (DAA) were at least significant liver fibrosis, severe extrahepatic manifestations of HCV, and high risk of HCV transmissibility.

Results

The reference population and the sample size were 38904 and 1588 patients, respectively. The prevalence of HCV-Abs in 2002, 2009, 2015, and 2016 was 60.8%, 50.2%, 37.7%, and 34.6%, respectively (P trend <.001, from 2002 to 2015). The prevalence of active HCV in 2002, 2009, 2015, and 2016 was 54.0%, 34.0%, 22.1%, and 11.7%, respectively (P trend <.001). The anti-HCV treatment uptake in 2002, 2009, 2015, and 2016 was 23.0%, 48.0%, 59.3%, and 74.7%, respectively (P trend <.001). In 2016, HCV-related cirrhosis was present in 7.6% of all HIV-infected individuals, 15.0% of patients with active HCV, and 31.5% of patients who cleared HCV after anti-HCV therapy.

Conclusions

Our findings suggest that with universal access to DAA-based therapy and continued efforts in prevention and screening, it will be possible to eliminate active HCV among HIV-infected individuals in Spain in the short term. However, the burden of HCV-related cirrhosis will continue to be significant among HIV-infected individuals.

Maraviroc ameliorates the increased adipose tissue macrophage recruitment induced by a high-fat diet in a mouse model of obesity

BACKGROUND

Any strategy designed to decrease the macrophage content in adipose tissue (AT) is of great value as a way to decrease inflammation in this fat depot and also as a way to prevent or treat obesity and associated disorders. Maraviroc (MVC), a CCR5 antagonist approved for the treatment of HIV-infected patients, has beneficial effects on metabolism. The objective of this study was to investigate the effects of MVC on AT macrophage recruitment in a mouse model of obesity. The plausible underlying mechanisms of action were also investigated.

METHODS

32 male C57BL/6 mice were randomly assigned to the following groups: control, MVC (300 mg/l MVC in drinking water), high-fat diet (HFD) or HFD+MVC. After 16 weeks of treatment, histopathological and molecular analyses were performed on epididymal fat.

RESULTS

Our results demonstrated that MVC reduced the presence of macrophages in epididymal fat despite the ingestion of an HFD. The inhibition of MCP-1 gene expression and JNK signalling pathway along with the upregulation of protective cytokines such as cardiotrophin-1 could contribute to these actions. MVC effects on AT macrophage recruitment were associated with a lower body weight gain and a partial improvement in insulin resistance despite an HFD.

CONCLUSIONS

We have demonstrated the ability of MVC to ameliorate the increased AT macrophage recruitment induced by an HFD in a mouse model of obesity. These actions could be of interest when designing antiretroviral treatments in HIV-patients.

Maraviroc, a CCR5 antagonist, ameliorates the development of hepatic steatosis in a mouse model of non-alcoholic fatty liver disease (NAFLD)

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the general population. The NAFLD spectrum ranges from simple steatosis to cirrhosis. The chemokine CCL5/RANTES plays an important role in the progression of hepatic inflammation and fibrosis. The objective of this study was to examine the effects of maraviroc, a CCR5 antagonist, on liver pathology in a NAFLD mouse model.

METHODS

A total of 32 male C57BL/6 mice were randomly assigned to one of four groups: (i) control group (chow diet plus tap water); (ii) maraviroc group (chow diet plus maraviroc in drinking water); (iii) high-fat diet (HFD) group (HFD plus tap water); and (iv) maraviroc/HFD group (HFD plus maraviroc). All mice were sacrificed 16 weeks after the beginning of the experiment. Biochemical analyses and liver examinations were performed.

RESULTS

Mice in the HFD group showed a tendency towards increased body mass gain and liver damage compared with the maraviroc/HFD group. Moreover, liver weight in the HFD group was significantly higher than in the maraviroc/HFD group. Hepatic triglyceride concentration in the maraviroc/HFD group was significantly lower than in the HFD group. Interestingly, the maraviroc/HFD group exhibited a lower degree of steatosis. Furthermore, hepatic CCL5/RANTES expression was significantly lower in the maraviroc/HFD group than in the HFD group. Overall, no differences were observed between the control group and the maraviroc group.

CONCLUSIONS

Maraviroc ameliorates hepatic steatosis in an experimental model of NAFLD.

Maraviroc, a CCR5 antagonist, prevents development of hepatocellular carcinoma in a mouse model

Chronic liver disease may result in a sequential progression through fibrosis, cirrhosis and lead, eventually, to hepatocellular carcinoma (HCC). Hepatic stellate cells (HSC) seem to be responsible for the fibrogenic response through the activation of an autocrine loop involving the chemokine receptor, CCR5. However, the role of CCR5 in HCC remains poorly understood. Since this receptor is also one of the main ports of entry for the human immunodeficiency virus (HIV), several CCR5 inhibitors are being used in the clinic to reduce viral load. We used one of these inhibitors, maraviroc (MVC), in a mouse model of diet-induced HCC to investigate whether this intervention would reduce disease progression. Animals treated with MVC on top of a normal control diet did not present any evidence of toxicity or any morphological change when compared with non-treated mice. Animals treated with MVC presented higher survival, less liver fibrosis, lower levels of liver injury markers and chemokines, less apoptosis, lower proliferation index, and lower tumor burden than their counterparts receiving only the hepatotoxic diet. In addition, MVC inhibits HSC activation markers such as phosphorylation of p38 and ERK, and increases hepatocyte survival. This study suggests that MVC, a well tolerated and clinically characterized drug, may be used as a preventative treatment for HCC. Clinical studies are needed to demonstrate the efficacy of this drug, or other CCR5 inhibitors, in patients with high risk of developing HCC.

Rickettsia parkeri: a Rickettsial pathogen transmitted by ticks in endemic areas for spotted fever rickettsiosis in southern Uruguay

At first Rickettsia conorii was implicated as the causative agent of spotted fever in Uruguay diagnosed by serological assays. Later Rickettsia parkeri was detected in human-biting Amblyomma triste ticks using molecular tests. The natural vector of R. conorii, Rhipicephalus sanguineus, has not been studied for the presence of rickettsial organisms in Uruguay. To address this question, 180 R. sanguineus from dogs and 245 A. triste from vegetation (flagging) collected in three endemic localities were screened for spotted fever group (SFG) rickettsiosis in southern Uruguay. Tick extracted DNA pools were subjected to PCR using primers which amplify a fragment of the rickettsial gltA gene. Positive tick DNA pools with these primers were subjected to a second PCR round with primers targeting a fragment of the ompA gene, which is only present in SFG rickettsiae. No rickettsial DNA was detected in R. sanguineus. However, DNA pools of A. triste were found to be positive for a rickettsial organism in two of the three localities, with prevalences of 11.8% to 37.5% positive pools. DNA sequences generated from these PCR-positive ticks corresponded to R. parkeri. These findings, joint with the aggressiveness shown by A. triste towards humans, support previous data on the involvement of A. triste as vector of human infections caused by R. parkeri in Uruguay.

Minimal effects of Darunavir on adipocyte differentiation and metabolism in 3T3-L1 cells

Darunavir (DRV) has been confirmed to be an effective option for antiretroviral-naïve and experienced patients. It results in a more favorable lipid and glucose profile than other antiretrovirals. The objective of this study was to investigate the molecular mechanisms that could underline the lack of toxicity of DRV to metabolism and the better profile observed in HIV-infected patients in comparison with other drugs. The effects of DRV on adipogenesis were evaluated by oil red O staining after 8 days of induction of differentiation in 3T3-L1 cells, a very adequate and convenient cell culture model for investigation of adipose function. Several adipogenic genes (C/EBPα, PPARγ, Pref-1, and AP2) were analyzed by real time-PCR. Fully differentiated adipocytes were also incubated with DRV for 24 h and glucose utilization and lactate and glycerol production were quantified by use of an autoanalyzer. No effects of DRV on murine adipocyte differentiation were observed. Significant decreases in lipolysis, glucose uptake, and lactate production were observed at the highest concentration used (50 μM:) (p < 0.01-p < 0.001). However, DRV treatment did not modify the percentage of glucose transformed into lactate. Co-treatment with RTV did not induce any further effects on lipolysis and glucose metabolism. This study suggests that the decrease in lipolysis observed after DRV treatment could explain, at least in part, the lower plasma lipids observed in patients under DRV/r treatment in comparison with other drugs. The lack of effects of RTV co-treatment on glucose and lipid metabolism emphasizes the safety of this treatment.

Neutral actions of Raltegravir on adipogenesis, glucose metabolism and lipolysis in 3T3-L1 adipocytes

Raltegravir (RAL) has been shown to be virologically effective in both treatment naive and triple class resistant patients. A more favourable metabolic profile associated with RAL in comparison with other antiretroviral drugs has also been observed. The aim of this study was to investigate the molecular mechanisms that could explain the lack of toxicity of this drug in metabolism. Thus, the effects of RAL on adipogenesis and adipocyte metabolism were analyzed using 3T3-L1 cells, a very adequate and convenient cell culture model for the investigation of adipose differentiation and metabolism. The effects of RAL on adipogenesis were evaluated by the Oil Red O staining after 8 days of induction of differentiation. Several adipogenic genes (C/EBP, PPAR, Pref-1 and AP2) were analyzed by real time PCR. Fully differentiated adipocytes were also incubated with RAL for 24 hours and glucose utilization, lactate production and glycerol release were analyzed. Thus, minimal effects of RAL on murine adipocyte differentiation were observed. Basal glucose uptake and lactate production were not affected by RAL at any of the concentrations used. No effects were also found on the percentage of glucose that is metabolized to lactate. Lipolysis was only slightly inhibited by Raltegravir (-10%) at the highest concentration used (50 µM), while no effects were observed with lower doses. Our results suggest that the absence of significant actions of RAL on adipogenesis and glucose and lipid metabolism in adipocytes could explain, at least in part, the neutral metabolic effects of RAL in clinical studies.

[Treatment of human infections caused by Bartonella spp.]

Infections by Bartonella spp. include a wide spectrum of emerging and re-emerging infectious diseases. There is not a universal therapy for this infection, therefore treatment should be chosen individually. The aim of this review is to update the therapeutics aspects of this kind of infections.

Detection of Rickettsia spp. in Haemaphysalis ticks collected in La Rioja, Spain

In an attempt to know the potential risk of human disease after exposure to ticks in La Rioja (North of Spain), the objective of our study was to investigate the presence of Rickettsia species in Haemaphysalis ticks collected in our area. A total of 177 Haemaphysalis spp. belonging to three species (H. punctata, H. sulcata, and H. inermis) were subjected to DNA extraction and tested by polymerase chain reaction (PCR) targeting three rickettsial genes: gltA, ompB, and ompA. Six (3 H. inermis, 2 H. punctata, and 1 H. sulcata) of the 177 specimens were found to be infected (3.4%). The rickettsiae in H. inermis ticks (n = 3) were identified as Rickettsia aeschlimannii by sequencing of the genes coding for gltA, ompB, and ompA. Nucleotide sequences from H. punctata and H. sulcata samples that yielded PCR products (n = 3), showed >99% similarity with sequences of Rickettsia endosymbiont of H. sulcata and 'Candidatus Rickettsia hoogstraalii' for gltA and ompB genes, respectively. Attempts to amplify ompA from these two H. punctata and one H. sulcata failed. This study suggests that H. inermis could be a vector for tick-borne spotted fever caused by R. aeschlimannii in the north of Spain. Further studies on characterization and culture of rickettsial endosymbionts found in Haemaphysalis spp. should be performed.

Detection of Alpha and Gamma-Proteobacteria in Amblyomma triste (Acari: Ixodidae) from Uruguay

Amblyomma triste is the most prevalent tick species reported in human tick bites in Uruguay and has been found to be infected with Rickettsia parkeri, but no other microorganisms have been reported from this tick. A sample of 254 adults of A. triste was collected by flagging on vegetation in suburban areas in southern Uruguay. Pools of five ticks were assembled and a screening for the DNA from the resulting 51 pools was realized by PCR assays using primers for amplifying a fragment of 16S rRNA gene for members of Anaplasmataceae. Seventeen pools were positive (33%) and the sequenciation of the gene fragment amplified revealed the presence of a putative new Alpha-Proteobacterium (denominated Atri-uru). The phylogenetic analysis showed that this microorganism is closely related to the symbiont of I. ricinus denominated 'Candidatus Midichloria mitochondrii' and other associated organisms. This rickettsial symbiont of ticks is included in a recent new clade proposed for the Alpha subclass of the Proteobacteria. The discovery of this bacterium in A. triste is the first evidence of this group of Rickettsiales detected in the Genus Amblyomma, and the first record in South America. Also, in two of 17 positive samples a Gamma-Proteobacterium related to Francisella-like organisms was detected.

Detection of Rickettsia africae in Rhipicephalus (Boophilus) decoloratus ticks from the Republic of Botswana, South Africa

A total of 53 engorged adult ticks belonging to the species Rhipicephalus (Boophilus) decoloratus (N = 9), Rhipicephalus evertsi evertsi (N = 27), Rhipicephalus appendiculatus (N = 9), Amblyomma hebraeum (N = 5), and Hyalomma marginatum turanicum (N = 3), were removed from oryx in Botswana (South Africa). They were tested for the presence of spotted fever group (SFG) Rickettsia and Anaplasma phagocytophilum using polymerase chain reaction (PCR). Seventy-seven percent of R. decoloratus as well as twenty percent of A. hebraeum were positive for ompA, gltA and 16S rRNA SFG Rickettsia PCR assays. All nucleotide sequences were homologous to Rickettsia africae, the agent of African tick-bite fever (ATBF). None of the tested ticks was positive for 16S rRNA A. phagocytophilum PCR assays. These results suggest for the first time that R. decoloratus ticks may be reservoirs of R. africae, and support the ATBF risk in this area.

Cluster of cases of human Rickettsia felis infection from Southern Europe (Spain) diagnosed by PCR

The first cluster of cases of human Rickettsia felis infection in Spain diagnosed by PCR is reported.

Rickettsia slovaca Infection: DEBONEL/TIBOLA

This study describes the epidemiological, clinical, and microbiological characteristics of a new tick-borne disease in Spain-Dermacentor-borne necrosis erythema lymphadenopathy (DEBONEL). The clinical presentations include an eschar at the site of the tick bite, surrounded by an erythema and painful regional lymphadenopathy. The disease appears during the colder months and its vector is Dermacentor marginatus (D. marginatus). From January 1990 to December 2004, 54 patients presented at Hospital of La Rioja with these clinical and epidemiological data. The ratio of females to males was 32/22. The average age was 37 years. In all cases tick bites were located on the upper body (90% on the scalp). The median incubation period was 4.7 days. Signs and symptoms were mild in all cases. Only a small number of patients presented mild and nonspecific abnormalities in a complete blood cell count and mild elevation of erythrocyte sedimentation rates and C-protein reactive and liver enzyme levels. Serological evidence of acute rickettsiosis was observed in 19 patients (61%). In 29% sera tested by polymerase chain reactions (PCRs) were positive. The sequence obtained from a PCR product revealed 98% identity with Rickettsia sp. strains RpA4, DnS14, and DnS28. All ticks removed from patients were PCR-positive. Sequencing showed 8 of them identified as R. slovaca and 2 as Rickettsia sp. strains RpA4, DnS14, and DnS28.

Prevalence of Rickettsia felis-like and Bartonella Spp. in Ctenocephalides felis and Ctenocephalides canis from La Rioja (Northern Spain)

Our aim was to determine the presence of Rickettsia spp. and Bartonella spp. in Ctenocephalides felis and Ctenocephalides canis from La Rioja (Spain). A total of 88 specimens were tested by polymerase chain reaction (PCR) using gltA and ompB genes as targets for Rickettsia spp., and 16S rRNA and ribC genes for Bartonella spp. Rickettsia felis-like (28.4%), Bartonella clarridgeiae (6.8%), and Bartonella henselae (3.4%) were detected in Ctenocephalides spp. Other Bartonella sp. different from B. clarridgeiae and B. henselae could also be present in fleas from La Rioja.

Prevalence of Spotted Fever Group Rickettsia Species Detected in Ticks in La Rioja, Spain

Our objective was to learn the prevalence of spotted fever group (SFG) Rickettsia detected in ticks in La Rioja, in the north of Spain. From 2001 to 2005, 496 ticks representing 7 tick species were analysed at the Hospital de La Rioja. Ticks were removed from humans with or without rickettsial syndrome (n = 59) or collected from mammals (n = 371) or from vegetation by dragging (n = 66). The presence of SFG Rickettsia in these ticks was investigated by semi-nested PCR (ompA gene) and sequencing. A phylogenetic tree using Clustal method (neighbor-joining) was constructed with these data. Only 3 of 170 Hyalomma marginatum ticks carried SFG Rickettsia. Sequencing analysis demonstrated the presence of Rickettsia aeschlimannii (1.8%). Furthermore, Rickettsia massiliae and BAR29 were found in 3 of 120 Rhipicephalus sanguineus specimens (2.5%). In contrast, 81 of 83 tested Dermacentor marginatus ticks were PCR-positive (97%). Rickettsia slovaca (40.6%) and Rickettsia sp. strains RpA4, DnS14, DnS28 and JL-02 (59.3%) were found within this tick species. No SFG Rickettsia was detected using ompA primers when Ixodes ricinus, Rhipicephalus bursa, Rhipicephalus turanicus, Rhipicephalus eversti eversti, Hyalomma detritum scupense and Rhipicephalus sp. were analyzed. We detected 17.5% of ticks associated with different SFG Rickettsia: R. aeschlimannii, R. massiliae, BAR29, R. slovaca and Rickettsia sp. strains RpA4, DnS14, DnS28 and JL-02. Their presence has to be taken into account since most of them have been recognized as human pathogens.

Prevalence of Rickettsia felis in Ctenocephalides felis and Ctenocephalides canis from Uruguay

Our aim was to determine the presence of Rickettsia spp. in 66 fleas from Uruguay. Rickettsial DNA was amplified using gltA and ompB PCR primers. Rickettsia spp. were found in 41% of the fleas (25 Ctenocephalides felis and 2 Ctenocephlides canis). Sequences resulted in the identification of Rickettsia felis and four genotypes closely related to this species (Rickettsia sp. TwKM03, California 2, Hf187, and RF2125). The presence of R. felis in fleas from Uruguay in was demonstrated. This is the second species of Rickettsia identified in Uruguay in the past 2 years using molecular approaches, and it is helping to clarify the etiology of rickettsial diseases in the region.

Detection of a Non-Pathogenic Variant of Anaplasma phagocytophilum in Ixodes ricinus from La Rioja, Spain

Our aim was to identify variants of Anaplasma phagocytophilum 16S rRNA gene sequences among products amplified from Ixodes ricinus collected in La Rioja, Spain. A. phagocytophilum AP-variant 1, reported as non-pathogenic, was detected in 12 samples (two adults and ten nymphs). This finding could justify the low incidence of human anaplasmosis in our area, despite the high prevalence of A. phagocytophilum in ticks.

Dexamethasone represses cAMP rapid upregulation of TRH gene transcription: identification of a composite glucocorticoid response element and a cAMP response element in TRH promoter

Hypothalamic proTRH mRNA levels are rapidly increased (at 1 h) in vivo by cold exposure or suckling, and in vitro by 8Br-cAMP or glucocorticoids. The aim of this work was to study whether these effects occurred at the transcriptional level. Hypothalamic cells transfected with rat TRH promoter (-776/+85) linked to the luciferase reporter showed increased transcription by protein kinase (PK) A and PKC activators, or by dexamethasone (dex), but co-incubation with dex and 8Br-cAMP decreased their stimulatory effect (as observed for proTRH mRNA levels). These effects were also observed in NIH-3T3-transfected cells supporting a characteristic of TRH promoter and not of hypothalamic cells. Transcriptional regulation by 8Br-cAMP was mimicked by noradrenaline which increased proTRH mRNA levels, but not in the presence of dex. PKA inhibition by H89 avoided 8Br-cAMP or noradrenaline stimulation. TRH promoter sequences, cAMP response element (CRE)-like (-101/-94 and -59/-52) and glucocorticoid response element (GRE) half-site (-210/-205), were analyzed by electrophoretic mobility shift assays with nuclear extracts from hypothalamic or neuroblastoma cultures. PKA stimulation increased binding to CRE (-101/-94) but not to CRE (-59/-52); dex or 12-O-tetradecanoylphorbol-13-acetate (TPA) increased binding to GRE, a composite site flanked by a perfect and an imperfect activator protein (AP-1) site in the complementary strand. Interference was observed in the binding of CRE or GRE with nuclear extracts from cells co-incubated for 3 h with 8Br-cAMP and dex; from cells incubated for 1 h, only the binding to GRE showed interference. Rapid cross-talk of glucocorticoids with PKA signaling pathways regulating TRH transcription constitutes another example of neuroendocrine integration.

Development of pro-TRH gene expression in primary cultures of fetal hypothalamic cells

Little is known about the temporal relationship and the sequential steps for peptide biosynthesis during the terminal differentiation of the peptide phenotype in central nervous system. Analysis of the TRH phenotype in primary cultures of rat fetal day 17 hypothalamic cells has shown that TRH levels start increasing only after a week in culture, in contrast with in vivo data showing a steady increase during late fetal life. The purpose of this study was to compare the developmental patterns of TRH and pro-TRH mRNA levels in vitro to determine whether the initial low and steady levels of TRH are due to deficient transcription. Pro-TRH mRNA levels were detected by semi-quantitative RT-PCR through the development of primary cultures of serum-supplemented hypothalamic fetal cells from 17 day old embryos. Pro-TRH mRNA levels per dish increased steadily since the beginning of the culture. In contrast, TRH levels per dish were low and stable during the first week increasing afterwards, but remaining low compared to equivalent in vivo values. Pro-TRH mRNA levels per hypothalamus increased between fetal day 17 and postnatal 14, suggesting that the in vitro pattern of pro-TRH mRNA development mimics that occurring in vivo. These data show that pro-TRH gene expression does not limit TRH accumulation in vitro suggesting that the transcriptional and post-transcriptional programs leading to peptide accumulation are established independently.

BDNF increases the early expression of TRH mRNA in fetal TrkB+ hypothalamic neurons in primary culture

Known effects of neurotrophins in the developing central nervous system include induction or regulation of peptide expression. Hypothalamic postmitotic thyrotropin-releasing hormone (TRH)-producing neurons may require neurotrophins for survival and/or differentiation. This issue was investigated using primary cell cultures derived from 17-day-old fetal rat hypothalamus seeded in serum-free medium and analysed up to 4 days in vitro culture. Neurotrophin receptor (TrkB and TrkC) mRNA expression was detected by RT-PCR in fetal hypothalamus and throughout the culture period. Western blots confirmed the expression of the full-length proteins in vitro. Semi-quantitative RT-PCR showed that the addition of brain-derived neurotrophic factor (BDNF) increases TRH mRNA levels while the addition of neurotrophin-3 does not. TRH cell content was not modified. Studies on the effect of cell density or homologous conditioned medium demonstrated that endogenous factors probably contribute to determine TRH mRNA levels. One of these factors was BDNF because basal TRH mRNA levels were reduced by the addition of a Trk inhibitor or anti-BDNF. TrkB mRNA was expressed in 27% of cells and TRH mRNA in 2% of cells. The number of TRH+ cells was not affected by BDNF treatment. Forty-eight per cent of TRH neurons contained TrkB mRNA; these neurons had higher amounts of TRH mRNA than TrkB- neurons. Only TrkB+ cells responded to BDNF by increasing their TRH mRNA levels suggesting that BDNF may directly affect TRH biosynthesis. In conclusion, fetal hypothalamic TRH neurons are probably heterogeneous in regard to the neurotrophic factors enhancing peptide and mRNA levels. BDNF enhances TRH mRNA levels in a population of TrkB+ fetal hypothalamic TRHergic neurons in primary culture. However, additional influences may be necessary for the establishment of peptide phenotype in the TrkB+ neurons.

Acute ethanol administration induces changes in TRH and proenkephalin expression in hypothalamic and limbic regions of rat brain

Thyrotropin releasing hormone (TRH) present in several brain areas has been proposed as a neuromodulator. Its administration produces opposite effects to those observed with acute ethanol consumption. Opioid peptides, in contrast, have been proposed to mediate some of the effects of alcohol intoxication. We measured TRH content and the levels of its mRNA in hypothalamic and limbic zones 1-24 h after acute ethanol injection. We report here fast and transient changes in the content of TRH and its mRNA in these areas. The levels of proenkephalin mRNA varied differently from those of proTRH mRNA, depending on the time and region studied. Wistar rats were administered one dose of ethanol (intraperitoneal, 3 g/kg body weight) and brains dissected in hypothalamus, hippocampus, amygdala, n. accumbens and frontal cortex, for TRH quantification by radioimmunoassay or for proTRH mRNA measurement by RT-PCR. After 1 h injection, TRH levels were increased in hippocampus and decreased in n. accumbens; after 4 h, it decreased in the hypothalamus, frontal cortex and amygdala, recovering to control values in all regions at 24 h. ProTRH mRNA levels increased at 1 h post-injection in total hypothalamus and hippocampus, while they decreased in the frontal cortex. The effect of ethanol was also studied in primary culture of hypothalamic cells; a fast and transient increase in proTRH mRNA was observed at 1 h of incubation (0.001% final ethanol concentration). Changes in the mRNA levels of proTRH and proenkephalin were quantified by in situ hybridization in rats administered ethanol intragastrically (2.5 g/kg). Opposite alterations were observed for these two mRNAs in hippocampus and frontal cortex, while in n. accumbens and the paraventricular nucleus of the hypothalamus, both mRNA levels were increased but with different kinetics. These results give support for TRH and enkephalin neurons as targets of ethanol and, as possible mediators of some of its observed behavioral effects.

Extracellular matrix proteins increase the expression of pro-TRH and pro-protein convertase PC1 in fetal hypothalamic neurons in vitro

External clues for neuron development include extracellular matrix (ECM) molecules. To explore ECM influence on the early development of peptide phenotype in the CNS, we have compared pro-TRH levels in primary cultures of rat hypothalamic cells plated either on poly-lysine (PL) (control) or on PL plus one of various ECM molecules at 10 microgram/ml. Fetal day 17 cells plated at a density of 1250/mm(2) were grown in a serum free medium made of Neurobasal medium supplemented with B27 (GIBCO). Cultures, consisting mainly of neurons, were analyzed at DIV 2. ECM proteins induced morphological effects in agreement with previously published studies. The amount of pro-TRH per dish, quantified by Western blotting, was increased to 275% for laminin, 191% for fibronectin and 173% for tenascin-C (control=100%); there was no effect of vitronectin. Laminin or fibronectin did not change pro-TRH mRNA or TRH levels but enhanced levels of the pro-protein convertase PC1 suggesting that the ECM molecules did regulate the translational status of pro-TRH. In conclusion, we have shown that some ECM proteins increased pro-TRH level in vitro; this may contribute to the enhancement of pro-TRH levels observed early in vivo in the hypothalamus.

Dexamethasone rapidly regulates TRH mRNA levels in hypothalamic cell cultures: interaction with the cAMP pathway

The biosynthesis of thyrotropin-releasing hormone (TRH) in the hypothalamic paraventricular nucleus (PVN) is subject to neural and hormonal regulations. To identify some of the potential effectors of this modulation, we incubated hypothalamic dispersed cells with dexamethasone for short periods of time (1-3 h) and studied the interaction of this hormone with protein kinase C (PKC) and PKA signaling pathways. TRH mRNA relative changes were determined by the RT-PCR technique. One hour incubation with 10(-10)-10(-4) M dexamethasone produced a concentration-dependent biphasic effect: an inhibition was observed on TRH mRNA levels at 10(-10) M, an increase above control at 10(-8)-10(-6) M and a reduction at higher concentrations (10(-5)- 10(-4) M). The stimulatory effect of 10(-8) M dexamethasone on TRH mRNA was essentially independent of new protein synthesis, as evidenced by cycloheximide pretreatment. Changes in TRH mRNA levels were reflected by enhanced TRH cell content. Incubation with a cAMP analogue (8-bromo-cAMP, 8Br-cAMP) or with a PKC activator (12-O-tetradecanoylphorbol-13-acetate, TPA) increased TRH mRNA levels after 1 and 2 h, respectively. An increase in TRH mRNA expression was observed by in situ hybridization of dexamethasone or 8Br-cAMP-treated cells. The interaction of dexamethasone, PKA and PKC signaling pathways was studied by combined treatment. The stimulatory effect of 10(-7) M TPA on TRH mRNA levels was additive to that of dexamethasone; in contrast, coincubation with 10(-3) M 8-Br-cAMP and dexamethasone diminished the stimulatory effect of both drugs. An inhibition was observed when the cAMP analogue was coincubated with TPA or TPA and dexamethasone. These results demonstrate that dexamethasone can rapidly regulate TRH biosynthesis and suggest a cross talk between cAMP, glucocorticoid receptors and PKC transducing pathways.

Multifactorial modulation of TRH metabolism

1. Thyrotropin releasing hormone (TRH), synthesized in the paraventricular nucleus of the hypothalamus (PVN), is released in response to physiological stimuli through median eminence nerve terminals to control thyrotropin or prolactin secretion from the pituitary. 2. Several events participate in the metabolism of this neuropeptide: regulation of TRH biosynthesis and release as well as modulation of its inactivation by the target cell. 3. Upon a physiological stimulus such as cold stress or suckling, TRH is released and levels of TRH mRNA increase in a fast and transient manner in the PVN; a concomitant increase in cfos is observed only with cold exposure. 4. Hypothalamic cell cultures incubated with cAMP or phorbol esters show a rise in TRH mRNA levels; dexamethasone produces a further increase at short incubation times. TRH mRNA are thus controlled by transsynaptic and hormonal influences. 5. Once TRH is released, it is inactivated by a narrow specificity ectoenzyme, pyroglutamyl peptidase II (PPII). 6. In adenohypophysis, PPII is subject to stringent control: positive by thyroid hormones and negative by TRH; other hypothalamic factors such as dopamine and somatostatin also influence its activity. 7. These combined approaches suggest that TRH action is modulated in a coordinate fashion.

Phorbol ester or cAMP enhance thyrotropin-releasing hormone mRNA in primary cultures of hypothalamic cells

Thyrotropin releasing hormone (TRH) biosynthesis is subject to a multifactorial control. TRH mRNA levels are negatively regulated by thyroid hormones in the paraventricular hypothalamic nucleus, and positively in cold exposure or suckling. Effect of second messenger pathways stimulation, a known response to membrane receptors, was studied in vitro; cultures of rat embryonic hypothalami (18 day gestation) were treated with 12-O-tetradecanoylphorbol-13-acetate (TPA, 100 nM) or dibutiryl cAMP (dBcAMP, 1 mM) for various times. Levels of TRH mRNA were raised after the first hour of dBcAMP or 2 h of TPA treatment and were still increased at 24 h. These results suggest a neural regulation of TRH biosynthesis.