Intrinsic risk factors for alpha-gal syndrome in a case-control study, 2019 to 2020.

BACKGROUND: Alpha-gal syndrome (AGS) is an allergy to galactose-α-1,3-galactose (alpha-gal), a carbohydrate found in most mammals. Evidence indicates that AGS develops after a tick bite, and in the United States, AGS is most associated with bites from Amblyomma americanum (lone star tick); however, not all persons bitten by ticks develop clinical AGS. OBJECTIVE: To investigate intrinsic risk factors associated with the development of AGS. METHODS: We performed a case-control study among adults presenting for diagnosis or management of AGS at an allergy clinic in North Carolina during 2019 to 2020 and compared them with controls enrolled from 2 nearby internal medicine clinics. A questionnaire gathered epidemiologic and tick exposure data, and blood was obtained for alpha-gal-specific IgE and other testing. RESULTS: The 82 enrolled case patients and 191 controls did not differ significantly by age or sex. Case patients were more likely than controls to have A or O blood types (non B-antigen), have experienced childhood allergies, and have a family history of AGS and other food allergies. Case patients were also more likely to report experiencing long healing times for insect bites or stings and a family history of allergy to stinging or biting insects. CONCLUSION: This study suggested that intrinsic factors contribute to risk of developing AGS. Some traits are genetic, but common behaviors among households and family units likely also contribute. Identification of these risk factors can inform personal risk, aid health care providers in understanding susceptible populations, and contribute to ongoing understanding of AGS epidemiology.

The Effect of Age on Dengue Presentation and the Diagnostic Accuracy of the 2015 Pan American Health Organization Case Criteria in a Puerto Rican Cohort.

Background: We evaluated dengue presentation by age, the performance of the 2015 Pan American Health Organization (PAHO) case criteria in identifying dengue cases, and variables to improve specificity. Methods: Patients with fever ≤7 days (N = 10 408) were recruited from 2 emergency departments from May 2012 through December 2015. Serum samples were tested for dengue, chikungunya, and nasopharyngeal swabs for respiratory viruses. Smoothing splines assessed differences in the frequencies of signs/symptoms by age. Least absolute shrinkage and selection operator regressions identified the variables that best predicted dengue. Results: Among 985 dengue cases, children aged <5 years were least likely to have leukopenia, but most likely to have rash and petechiae. Adults had the highest odds of aches/pains and headaches/retro-orbital pain. The 2015 PAHO criteria had sensitivity of 93% and specificity of 25%. Specificity could be improved by requiring at least 2 of the following criteria: vomiting/nausea, petechiae, rash, or leukopenia (specificity 68%, sensitivity 71%) or by using 2015 PAHO criteria plus either (1) aspartate aminotransferase >50 IU/L or platelet count <100 000 platelets/µL (specificity 81%, sensitivity 56%) or (2) itchy skin or absence of rhinorrhea or cough (specificity 51%, sensitivity 82%). Conclusions: The 2015 PAHO dengue case criteria had excellent sensitivity but poor specificity. This can be improved by adding signs/symptoms associated with dengue diagnosis.

Tick bite as a risk factor for alpha-gal-specific immunoglobulin E antibodies and development of alpha-gal syndrome.

BACKGROUND: The disaccharide galactose-α-1,3-galactose (alpha-gal) is expressed in mammals other than humans, apes, and old-world monkeys. In humans, elevated immunoglobulin E (IgE) antibodies specific for alpha-gal can result in allergic hypersensitivity known as alpha-gal syndrome (AGS). Case reports and series suggest that tick bites can induce alpha-gal-specific IgE (sIgE) antibodies. OBJECTIVE: To evaluate tick exposure as a risk factor for AGS and elevated alpha-gal sIgE level. METHODS: We conducted a case-control study comparing patients with AGS from a North Carolina allergy clinic with controls who were patients at a nearby internal medicine clinic. Cases and controls were administered a questionnaire to obtain information about demographics, home environment, outdoor activities, and recollection of tick bite. Serum samples taken at the time of enrollment were tested for total IgE, alpha-gal sIgE, and antibodies to other tick-borne pathogens. RESULTS: The patients with AGS were more likely to recall finding a tick on themselves (odds ratio [OR], 11.20; 95% confidence interval [CI], 4.97-25.15), live near wooded forest (OR, 2.27; 95% CI, 0.92-5.55), and spend 17 or more hours per week outdoors in wooded areas (OR, 5.58; 95% CI, 2.56-12.19). The patients with AGS were also more likely to report 4 or more tick bites (OR, 33.05; 95% CI, 9.92-155.12) and reactions at the site of tick bites (OR, 7.93; 95% CI, 3.74-16.80). Furthermore, elevated alpha-gal sIgE level was observed in 33% of the controls and was associated with tick exposure in the controls (OR, 4.25; 95% CI, 2.21-8.18). CONCLUSION: The results define tick bite as a risk factor for AGS and elevated alpha-gal sIgE level.

Clinical and laboratory features of patients diagnosed with alpha-gal syndrome-2010-2019.

BACKGROUND: Alpha-gal syndrome (AGS) is an IgE-mediated allergy to galactose-alpha-1,3-galactose. Clinical presentation ranges from hives to anaphylaxis; episodes typically occur 2-6 h after exposure to alpha-gal-containing products. In the United States, lone star tick bites are associated with the development of AGS. To characterize features of AGS, we evaluated a cohort of patients presenting for care at the University of North Carolina, focusing on symptoms, severity, and identifying features unique to specific alpha-gal-containing product exposures. METHODS: We performed a chart review and descriptive analysis of 100 randomly selected patients with AGS during 2010-2019. RESULTS: Median age at onset was 53 years, 56% were female, 95% reported White race, 86% reported a history of tick bite, and 75% met the criteria for anaphylaxis based on the involvement of ≥2 organ systems. Those reporting dairy reactions were significantly less likely to report isolated mucocutaneous symptoms (3% vs. 24%; ratio [95% CI]: 0.1 [0.1, 0.3]) than those who tolerated dairy, and were more likely to report gastrointestinal symptoms (79% vs. 59%; ratio [95% CI]: 1.3 [0.7, 2.6]), although this difference was not statistically significant. Dairy-tolerant patients demonstrated higher alpha-gal sIgE titers (as a percentage of total IgE) than dairy-reactive patients (GM 4.1 [95% CI: 2.7, 6.1] vs. GM 2.5 [95% CI: 1.3, 4.8], respectively; ratio -1.6 [95% CI: -1.0, 3.9]). CONCLUSION: While tick exposure is common in the southern United States, nearly all AGS patients reported a tick bite. Gastrointestinal symptoms were prominent among those reporting reactions to dairy. Anaphylaxis was common, underscoring the severity and need to raise awareness of AGS among patients and providers.

Predominance of Severe Plasma Leakage in Pediatric Patients With Severe Dengue in Puerto Rico.

BACKGROUND: We evaluated clinical and laboratory findings among patients with nonsevere or severe dengue in Puerto Rico to examine whether clinical manifestations vary by age. METHODS: During 2012-2014, we enrolled patients who arrived at the emergency department with fever or history of fever within 7 days of presentation. Serum samples were tested for dengue virus (DENV) by reverse transcriptase-polymerase chain reaction (RT-PCR) and IgM enzyme-linked immunosorbent assay (ELISA). Severe dengue was defined as severe plasma leakage or shock, severe bleeding, or organ involvement at presentation, during hospitalization, or follow-up. RESULTS: Of 1089 dengue patients identified, 281 (26%) were severe. Compared to those with nonsevere dengue, patients with severe dengue were more often aged 10-19 years (55% vs 40%, P < .001) and hospitalized (87% vs 30%, P < .001). Severe plasma leakage or shock was more common among children aged 0-9 (59%) or 10-19 years (86%) than adults (49%) (P < .01). Severe bleeding was less common among 10-19 year olds (24%) compared to 0-9 year olds (45%) and adults (52%; P < .01). CONCLUSIONS: Severe plasma leakage was the most common presentation among children, highlighting important differences from adults. Vaccination against dengue could help prevent severe dengue among children in Puerto Rico.

Large animal veterinarians' knowledge, attitudes, and practices regarding livestock abortion-associated zoonoses in the United States indicate potential occupational health risk.

OBJECTIVE: To understand large animal veterinarians' knowledge of select zoonotic diseases that cause livestock abortions and identify barriers to using personal protective equipment (PPE). SAMPLE: A convenience sample of 469 veterinarians currently working with livestock. PROCEDURES: We sent an electronic survey invitation to large animal veterinarians through various veterinary organizations. Respondents answered questions addressing knowledge and prior experience with select abortion-associated zoonotic diseases, resources available for infection control, attitudes and barriers to PPE use, and demographics. RESULTS: Median participant age was 49 years (range, 22 to 82 years), and 54% (235/438) were male. Half of veterinarians (185/348) were contacted 5 or fewer times per year to consult on livestock abortions. No veterinarians surveyed answered all questions on zoonotic disease transmission correctly. Personal protective equipment access varied, from 99% (289/290) having access to gloves to 20% (59/290) having access to respirators. Concerns for spreading disease to other animals (136/289 [47%]) and to other humans (108/287 [38%]) ranked as the most common reported motivators for PPE use. Reported barriers to PPE use among survey participants were the inconvenience of taking PPE into the field (101/286 [35%]) and the inconvenience of wearing PPE (97/286 [34%]). Access to PPE was not correlated with PPE use. CLINICAL RELEVANCE: Surveyed veterinarians had limited knowledge of transmission of select abortion-associated zoonotic diseases. Incomplete understanding might lead to inappropriate PPE selection, preventable disease exposure, or missed opportunities for client education. Inconvenience was a primary reason PPE was not used.

Estimating the early impact of the US COVID-19 vaccination programme on COVID-19 cases, emergency department visits, hospital admissions, and deaths among adults aged 65 years and older: an ecological analysis of national surveillance data.

BACKGROUND: In the USA, COVID-19 vaccines became available in mid-December, 2020, with adults aged 65 years and older among the first groups prioritised for vaccination. We estimated the national-level impact of the initial phases of the US COVID-19 vaccination programme on COVID-19 cases, emergency department visits, hospital admissions, and deaths among adults aged 65 years and older. METHODS: We analysed population-based data reported to US federal agencies on COVID-19 cases, emergency department visits, hospital admissions, and deaths among adults aged 50 years and older during the period Nov 1, 2020, to April 10, 2021. We calculated the relative change in incidence among older age groups compared with a younger reference group for pre-vaccination and post-vaccination periods, defined by the week when vaccination coverage in a given age group first exceeded coverage in the reference age group by at least 1%; time lags for immune response and time to outcome were incorporated. We assessed whether the ratio of these relative changes differed when comparing the pre-vaccination and post-vaccination periods. FINDINGS: The ratio of relative changes comparing the change in the COVID-19 case incidence ratio over the post-vaccine versus pre-vaccine periods showed relative decreases of 53% (95% CI 50 to 55) and 62% (59 to 64) among adults aged 65 to 74 years and 75 years and older, respectively, compared with those aged 50 to 64 years. We found similar results for emergency department visits with relative decreases of 61% (52 to 68) for adults aged 65 to 74 years and 77% (71 to 78) for those aged 75 years and older compared with adults aged 50 to 64 years. Hospital admissions declined by 39% (29 to 48) among those aged 60 to 69 years, 60% (54 to 66) among those aged 70 to 79 years, and 68% (62 to 73), among those aged 80 years and older, compared with adults aged 50 to 59 years. COVID-19 deaths also declined (by 41%, 95% CI -14 to 69 among adults aged 65-74 years and by 30%, -47 to 66 among those aged ≥75 years, compared with adults aged 50 to 64 years), but the magnitude of the impact of vaccination roll-out on deaths was unclear. INTERPRETATION: The initial roll-out of the US COVID-19 vaccination programme was associated with reductions in COVID-19 cases, emergency department visits, and hospital admissions among older adults. FUNDING: None.

COVID-19 vaccination coverage among hospital-based healthcare personnel reported through the Department of Health and Human Services Unified Hospital Data Surveillance System, United States, January 20, 2021-September 15, 2021.

To protect both patients and staff, healthcare personnel (HCP) were among the first groups in the United States recommended to receive the COVID-19 vaccine. We analyzed data reported to the U.S. Department of Health and Human Services (HHS) Unified Hospital Data Surveillance System on COVID-19 vaccination coverage among hospital-based HCP. After vaccine introduction in December 2020, COVID-19 vaccine coverage rose steadily through April 2021, but the rate of uptake has since slowed; as of September 15, 2021, among 3,357,348 HCP in 2,086 hospitals included in this analysis, 70.0% were fully vaccinated. Additional efforts are needed to improve COVID-19 vaccine coverage among HCP.

Reproductive incompatibility between Amblyomma maculatum (Acari: Ixodidae) group ticks from two disjunct geographical regions within the USA.

The Amblyomma maculatum Koch group of ixodid ticks consists of three species: A. maculatum, A. triste, and A. tigrinum. However, since Koch described this group in 1844, the systematics of its members has been the subject of ongoing debate. This is especially true of A. maculatum and A. triste; recent molecular analyses reveal insufficient genetic divergence to separate these as distinct species. Further confounding this issue is the discovery in 2014 of A. maculatum group ticks in southern Arizona (AZ), USA, that share morphological characteristics with both A. triste and A. maculatum. To biologically evaluate the identity of A. maculatum group ticks from southern Arizona, we analyzed the reproductive compatibility between specimens of A. maculatum group ticks collected from Georgia (GA), USA, and southern Arizona. Female ticks from both Arizona and Georgia were mated with males from both the Georgia and Arizona Amblyomma populations, creating two homologous and two heterologous F1 cohorts of ticks: GA ♀/GA ♂, AZ ♀/AZ ♂, GA ♀/AZ ♂, and AZ ♀/GA ♂. Each cohort was maintained separately into the F2 generation with F1 females mating only with F1 males from their same cohort. Survival and fecundity parameters were measured for all developmental stages. The observed survival parameters for heterologous cohorts were comparable to those of the homologous cohorts through the F1 generation. However, the F1 heterologous females produced F2 egg clutches that did not hatch, thus indicating that the Arizona and Georgia populations of A. maculatum group ticks tested here represent different biological species.

Serelaxin and the AT2 Receptor Agonist CGP42112 Evoked a Similar, Nonadditive, Cardiac Antifibrotic Effect in High Salt-Fed Mice That Were Refractory to Candesartan Cilexetil.

Fibrosis is involved in the majority of cardiovascular diseases and is a key contributor to end-organ dysfunction. In the current study, the antifibrotic effects of recombinant human relaxin-2 (serelaxin; RLX) and/or the AT2R agonist CGP42112 (CGP) were compared with those of the established AT1R antagonist, candesartan cilexetil (CAND), in a high salt-induced cardiac fibrosis model. High salt (HS; 5%) for 8 weeks did not increase systolic blood pressure in male FVB/N mice, but CAND treatment alone significantly reduced systolic blood pressure from HS-induced levels. HS significantly increased cardiac interstitial fibrosis, which was reduced by either RLX and/or CGP, which were not additive under the current experimental conditions, while CAND failed to reduce HS-induced cardiac fibrosis. The antifibrotic effects induced by RLX and/or CGP were associated with reduced myofibroblast differentiation. Additionally, all treatments inhibited the HS-induced elevation in tissue inhibitor of matrix metalloproteinases-1, together with trends for increased MMP-13 expression, that collectively would favor collagen degradation. Furthermore, these antifibrotic effects were associated with reduced cardiac inflammation. Collectively, these results highlight that either RXFP1 or AT2R stimulation represents novel therapeutic strategies to target fibrotic conditions, particularly in HS states that may be refractory to AT1R blockade.

Renal functional effects of the highly selective AT2R agonist, ß-Pro7 Ang III, in normotensive rats.

Recently, we designed a group of peptides by sequential substitution of the naturally occurring α-amino acid throughout the Ang III peptide sequence with the corresponding ß-amino acid. ß-Amino acid substitution at the proline residue of Ang III (ß-Pro7-Ang III) resulted in a highly selective AT2R ligand, demonstrating remarkable selectivity for the AT2R in both binding and functional studies. To provide additional functional evidence for the suitability of ß-Pro7 Ang III as a novel AT2R agonist, we tested effects of acute systemic administration of ß-Pro7-Ang III on renal hemodynamic and excretory function in anesthetized normotensive male and female rats. We also compared the natriuretic effects of acute intrarenal administration of native Ang III and ß-Pro7-Ang III in the presence of systemic AT1R blockade in anesthetized female rats to allow for the differentiation of systemic versus direct intrarenal natriuretic actions of ß-Pro7-Ang III. In both male and female rats, acute systemic administration of ß-Pro7-Ang III elicited renal vasodilatation and natriuresis. Notably, greater renal vasodilatory effects were observed in female versus male rats at the highest dose of ß-Pro7-Ang III administered. Moreover, intra-renal administration of ß-Pro7-Ang III produced significant natriuretic effects in female rats and, like Ang III, evoked AT2R translocation to the apical plasma membrane in renal proximal tubular cells. Taken together, our findings support the use of ß-Pro7-Ang III as a novel AT2R agonist and experimental tool for exploring AT2R function and its potential as a therapeutic target. Furthermore, our findings provide further evidence of a sex-specific influence of AT2R stimulation on renal function.

"They're Really PD Today".

The therapeutic relationship is of particular importance when working with patients with antisocial personality disorder, but despite this, there is a paucity of literature exploring student nurses' perceptions of developing a therapeutic relationship with such patients. Hence, this qualitative study explored the perceptions of second-year mental health nursing students of developing a therapeutic relationship with this patient group. Student nurses from a University in the Northwest of England participated in two focus groups, to compare the perceptions of a group of student nurses who had experience in secure settings (forensic hospital) with those who had not. Four key themes emerged: diagnosis, safety, engagement, and finally environmental influences. Both groups commented on looking beyond the diagnosis and seeing the person. The student nurses cited other staff in their clinical placement areas as hugely influential in terms of the development of their perceptions of patients with antisocial personality disorder and how to relate to them.

ß-Pro7Ang III is a novel highly selective angiotensin II type 2 receptor (AT2R) agonist, which acts as a vasodepressor agent via the AT2R in conscious spontaneously hypertensive rats.

We have previously shown that individual ß-amino acid substitution in angiotensin (Ang) II reduced Ang II type 1 receptor (AT1R) but not Ang II type 2 receptor (AT2R)-binding and that the heptapeptide Ang III exhibited greater AT2R:AT1R selectivity than Ang II. Therefore, we hypothesized that ß-amino-acid-substituted Ang III peptide analogues would yield highly selective AT2R ligands, which we have tested in binding and functional vascular assays. In competition binding experiments using either AT1R- or AT2R-transfected human embryonic kidney (HEK)-293 cells, novel ß-substituted Ang III analogues lacked appreciable AT1R affinity, whereas most compounds could fully displace (125)I-Sar(1)Ile(8) Ang II from AT2R. The rank order of affinity at AT2R was CGP42112 > Ang III > ß-Pro(7) Ang III=Ang II > ß-Tyr(4) Ang III ≥ PD123319 >> ß-Phe(8) Ang III >> ß Arg(2) Ang III=ß-Val(3) Ang III >> ß-Ile(5) Ang III. The novel analogue ß-Pro(7) Ang III was the most selective AT2R ligand tested, which was >20,000-fold more selective for AT2R than AT1R. IC50 values at AT2R from binding studies correlated with maximum vasorelaxation in mouse aortic rings. Given that ß-Pro(7) Ang III was an AT2R agonist, we compared ß-Pro(7) Ang III and native Ang III for their ability to reduce blood pressure in separate groups of conscious spontaneously hypertensive rats. Whereas Ang III alone increased mean arterial pressure (MAP), ß-Pro(7) Ang III had no effect. During low-level AT1R blockade, both Ang III and ß-Pro(7) Ang III, but not Ang II, lowered MAP (by ∼30 mmHg) at equimolar infusions (150 pmol/kg/min for 4 h) and these depressor effects were abolished by the co-administration of the AT2R antagonist PD123319. Thus, ß-Pro(7) Ang III has remarkable AT2R selectivity determined in binding and functional studies and will be a valuable research tool for insight into AT2R function and for future drug development.

Electronic sculpting of ligand-GPCR subtype selectivity: the case of angiotensin II.

GPCR subtypes possess distinct functional and pharmacological profiles, and thus development of subtype-selective ligands has immense therapeutic potential. This is especially the case for the angiotensin receptor subtypes AT1R and AT2R, where a functional negative control has been described and AT2R activation highlighted as an important cancer drug target. We describe a strategy to fine-tune ligand selectivity for the AT2R/AT1R subtypes through electronic control of ligand aromatic-prolyl interactions. Through this strategy an AT2R high affinity (Ki = 3 nM) agonist analogue that exerted 18,000-fold higher selectivity for AT2R versus AT1R was obtained. We show that this compound is a negative regulator of AT1R signaling since it is able to inhibit MCF-7 breast carcinoma cellular proliferation in the low nanomolar range.

Relaxin requires the angiotensin II type 2 receptor to abrogate renal interstitial fibrosis.

Fibrosis is a hallmark of chronic kidney disease, for which there is currently no effective cure. The hormone relaxin is emerging as an effective antifibrotic therapy; however, its mechanism of action is poorly understood. Recent studies have shown that relaxin disrupts the profibrotic actions of transforming growth factor-ß1 (TGF-ß1) by its cognate receptor, relaxin family peptide receptor 1 (RXFP1), extracellular signal-regulated kinase phosphorylation, and a neuronal nitric oxide synthase-dependent pathway to abrogate Smad2 phosphorylation. Since angiotensin II also inhibits TGF-ß1 activity through its AT2 receptor (AT2R), we investigated the extent to which relaxin interacts with the AT2R. The effects of the AT2R antagonist, PD123319, on relaxin activity were examined in primary rat kidney myofibroblasts, and in kidney tissue from relaxin-treated male wild-type and AT2R-knockout mice subjected to unilateral ureteric obstruction. Relaxin's antifibrotic actions were significantly blocked by PD123319 in vitro and in vivo, or when relaxin was administered to AT2R-knockout mice. While heterodimer complexes were formed between RXFP1 and AT2Rs independent of ligand binding, relaxin did not directly bind to AT2Rs but signaled through RXFP1-AT2R heterodimers to induce its antifibrotic actions. These findings highlight a hitherto unrecognized interaction that may be targeted to control fibrosis progression.

Direct AT2 receptor stimulation is athero-protective and stabilizes plaque in apolipoprotein E-deficient mice.

BACKGROUND: The angiotensin II type 2 receptor (AT2R) has been suggested to have an athero-protective role, however no studies have investigated the effect of direct stimulation of this receptor in atherosclerosis. Thus this study aimed to determine the effect of direct AT2R stimulation in setting of atherosclerosis, using the known AT2R agonist, CGP42112. METHODS AND RESULTS: Apolipoprotein E-deficient (ApoE(-/-)) mice were fed a high fat (21%) diet for 16 weeks, with subcutaneous infusions of CGP42112 (1, 5 or 10 µg/kg/min) administered via osmotic mini-pumps in the final 4 weeks. CGP42112 treatment at all doses significantly improved endothelial function (p<0.001) when compared to acetylcholine mediated-vasorelaxation in aorta taken from vehicle-treated ApoE(-/-) mice. In aortic segments adjacent to those used for vascular reactivity studies, CGP42112 treatment at all doses concomitantly increased eNOS immunoreactivity and protein levels whilst superoxide (O2(-)) production was significantly (p<0.01) decreased compared to levels measured in aorta from vehicle-treated ApoE(-/-) mice. Moreover, CGP42112 (1 µg/kg/min) treatment significantly attenuated (p<0.05) atherosclerotic lesion progression (assessed as both lipid deposits and luminal encroachment in thoracic aorta and aortic arch) and significantly increased plaque stability in the brachiocephalic artery, a region normally prone to rupture. Both the vaso- and athero-protective effects of CGP42112 (1 µg/kg/min) were reversed with co-infusion of the AT2R antagonist, PD123319, but not the MasR antagonist, A779. CONCLUSION: For the first time we have shown that direct stimulation of the AT2R improves endothelial function, reduces atherosclerotic lesion progression and mediates plaque stability with these effects at least partly due to restoration of nitric oxide bioavailability.

Update on the angiotensin AT(2) receptor.

It is quite well established that activation of the AT(2) receptor (AT(2)R) provides a counter-regulatory role to AT(1)R overactivity, particularly during pathological conditions. Indeed, a potential therapeutic role for the AT(2)R is currently being promulgated with the introduction of novel AT(2)R ligands such as compound 21 (C21). In this brief review, we will focus on recent evidence to suggest that AT(2)R exhibits promising organ protection in the context of the heart, kidney and brain, with inflammation and gender influencing outcome. However, this field is not without controversy since the 'flagship' ligand C21 has also come under scrutiny, although it is safe to say there is much evidence to support a potentially important role of AT(2)R in a number of cardiovascular diseases. This report updates recent data in this field.

Reversal of vascular macrophage accumulation and hypertension by a CCR2 antagonist in deoxycorticosterone/salt-treated mice.

Infiltration of macrophages into the artery wall plays detrimental roles during hypertension by promoting vascular inflammation and endothelial dysfunction, and it occurs via a chemo-attractant action of chemokines on macrophage cytokine receptors. We sought to identify the key chemokine receptors associated with macrophage infiltration into the vascular wall during deoxycorticosterone acetate (DOCA)/salt-induced hypertension in mice and to evaluate the impact of pharmacological inhibition of these receptors on blood pressure and leukocyte accumulation. Mice treated with DOCA/salt for 21 days displayed markedly elevated systolic blood pressure (158 ± 2 versus 114 ± 5 mm Hg in sham group; P<0.0001). Polymerase chain reaction screening via a gene array of 20 chemokine receptors indicated an increased expression of CCR2 in aortas of DOCA/salt-treated mice. Real-time polymerase chain reaction confirmed mRNA upregulation of CCR2 in aortas from DOCA/salt-treated animals and of the CCR2 ligands CCL2, CCL7, CCL8, and CCL12 (all >2-fold versus sham; P<0.05). Flow cytometry revealed 2.9-fold higher macrophage numbers (ie, CD45(+) CD11b(+) F4/80(+) cells) in the aortic wall of DOCA/salt versus sham-treated mice. Intervention with a CCR2 antagonist, INCB3344 (30 mg/kg per day, IP), 10 days after the induction of hypertension with DOCA/salt treatment, reduced the aortic expression of CCR2 mRNA and completely reversed the DOCA/salt-induced influx of macrophages. Importantly, INCB3344 substantially reduced the elevated blood pressure in DOCA/salt-treated mice. Hence, our findings highlight CCR2 as a promising therapeutic target to reduce both macrophage accumulation in the vascular wall and blood pressure in hypertension.

Neuroprotective effect of an angiotensin receptor type 2 agonist following cerebral ischemia in vitro and in vivo.

BACKGROUND: Intracerebral administration of the angiotensin II type 2 receptor (AT2R) agonist, CGP42112, is neuroprotective in a rat model of ischemic stroke. To explore further its possible cellular target(s) and therapeutic utility, we firstly examined whether CGP42112 may exert direct protective effects on primary neurons following glucose deprivation in vitro. Secondly, we tested whether CGP42112 is effective when administered systemically in a mouse model of cerebral ischemia. METHODS: Primary cortical neurons were cultured from E17 C57Bl6 mouse embryos for 9 d, exposed to glucose deprivation for 24 h alone or with drug treatments, and percent cell survival assessed using trypan blue exclusion. Ischemic stroke was induced in adult male C57Bl6 mice by middle cerebral artery occlusion for 30 min, followed by reperfusion for 23.5 h. Neurological assessment was performed and then mice were euthanized and infarct and edema volume were analysed. RESULTS: During glucose deprivation, CGP42112 (1x10-8 M and 1x10-7 M) reduced cell death by ~30%, an effect that was prevented by the AT2R antagonist, PD123319 (1x10-6 M). Neuroprotection by CGP42112 was lost at a higher concentration (1x10-6 M) but was unmasked by co-application with the AT1R antagonist, candesartan (1x10-7 M). By contrast, Compound 21 (1x10-8 M to 1x10-6 M), a second AT2R agonist, had no effect on neuronal survival. Mice treated with CGP42112 (1 mg/kg i.p.) after cerebral ischemia had improved functional outcomes over vehicle-treated mice as well as reduced total and cortical infarct volumes. CONCLUSIONS: These results indicate that CGP42112 can directly protect neurons from ischemia-like injury in vitro via activation of AT2Rs, an effect opposed by AT1R activation at high concentrations. Furthermore, systemic administration of CGP42112 can reduce functional deficits and infarct volume following cerebral ischemia in vivo.