Tuft cell-derived acetylcholine regulates epithelial fluid secretion

Tuft cells are solitary chemosensory epithelial cells that can sense lumenal stimuli at mucosal barriers and secrete effector molecules to regulate the physiology and immune state of their surrounding tissue. In the small intestine, tuft cells detect parasitic worms (helminths) and microbe-derived succinate, and signal to immune cells to trigger a Type 2 immune response that leads to extensive epithelial remodeling spanning several days. Acetylcholine (ACh) from airway tuft cells has been shown to stimulate acute changes in breathing and mucocilliary clearance, but its function in the intestine is unknown. Here we show that tuft cell chemosensing in the intestine leads to release of ACh, but that this does not contribute to immune cell activation or associated tissue remodeling. Instead, tuft cell-derived ACh triggers immediate fluid secretion from neighboring epithelial cells into the intestinal lumen. This tuft cell-regulated fluid secretion is amplified during Type 2 inflammation, and helminth clearance is delayed in mice lacking tuft cell ACh. The coupling of the chemosensory function of tuft cells with fluid secretion creates an epithelium-intrinsic response unit that effects a physiological change within seconds of activation. This response mechanism is shared by tuft cells across tissues, and serves to regulate the epithelial secretion that is both a hallmark of Type 2 immunity and an essential component of homeostatic maintenance at mucosal barriers.

The discovery of (1R, 3R)-1-(3-chloro-5-fluorophenyl)-3-(hydroxymethyl)-1,2,3,4-tetrahydroisoquinoline-6-carbonitrile, a potent and selective agonist of human transient receptor potential cation channel subfamily m member 5 (TRPM5) and evaluation of as a potential gastrointestinal prokinetic agent

This publication details the discovery of a series of selective transient receptor potential cation channel subfamily M member 5 (TRPM5) agonists culminating with the identification of the lead compound (1R, 3R)-1-(3-chloro-5-fluorophenyl)-3-(hydroxymethyl)-1,2,3,4-tetrahydroisoquinoline-6-carbonitrile (39). We describe herein our biological rationale for agonism of the target, the examination of the then current literature tool molecules, and finally the process of our discovery starting with a high throughput screening hit through lead development. We also detail the selectivity of the lead compound 39 versus related family members TRPA1, TRPV1, TRPV4, TRPM4 and TRPM8, the drug metabolism and pharmacokinetics (DMPK) profile and in vivo efficacy in a mouse model of gastrointestinal motility.

Identification of positive modulators of TRPM5 channel from a high-throughput screen using a fluorescent membrane potential assay

Transient Receptor Potential Melastatin 5 (TRPM5) is an intracellular calcium-activated cation-selective ion channel expressed in a variety of cell types. Dysfunction of this channel has recently been implied in a range of disease states including diabetes, enteric infections, inflammatory responses, parasitic infection and other pathologies. However, to date, agonists and positive modulators of this channel with sufficient selectivity to enable target validation studies have not been described, limiting the evaluation of TRPM5 biology and its potential as a drug target. We developed a high-throughput assay using a fluorescent membrane potential dye and a medium- and high-throughput electrophysiology assay using QPatch HTX and SyncroPatch 384PE. By employing these assays, we conducted a primary screening campaign and identified hit compounds as TRPM5 channel positive modulators. An initial selectivity profile confirmed hit selectivity to TRPM5 and is presented here. These small molecule TRPM5 compounds have a high potential both as early tool compounds to enable pharmacological studies of TRPM5 and as starting points for the development of potent, selective TRPM5 openers or positive modulators as novel drugs targeting several pathological states.

From High-Throughput Screening to Target Validation: Benzo[d]isothiazoles as Potent and Selective Agonists of Human Transient Receptor Potential Cation Channel Subfamily M Member 5 Possessing In Vivo Gastrointestinal Prokinetic Activity in Rodents

Transient receptor potential cation channel subfamily M member 5 (TRPM5) is a nonselective monovalent cation channel activated by intracellular Ca²⁺ increase. Within the gastrointestinal system, TRPM5 is expressed in the stoma, small intestine, and colon. In the search for a selective agonist of TRPM5 possessing in vivo gastrointestinal prokinetic activity, a high-throughput screening was performed and compound 1 was identified as a promising hit. Hit validation and hit to lead activities led to the discovery of a series of benzo[d]isothiazole derivatives. Among these, compounds 61 and 64 showed nanomolar activity and excellent selectivity (>100-fold) versus related cation channels. The in vivo drug metabolism and pharmacokinetic profile of compound 64 was found to be ideal for a compound acting locally at the intestinal level, with minimal absorption into systemic circulation. Compound 64 was tested in vivo in a mouse motility assay at 100 mg/kg, and demonstrated increased prokinetic activity.

Airway barrier dysfunction induced by exposure to carbon nanotubes in vitro: which role for fiber length?

Although carbon nanotubes (CNTs) are increasingly used, their biological effects are only incompletely characterized. However, experimental evidence suggests that the intratracheal instillation of CNTs causes the formation of interstitial granulomas and progressive pulmonary fibrosis in rodents. Using human epithelial Calu-3 cells as a model of airway epithelium in vitro, we have recently reported that the exposure to commercial multi-walled CNTs (MWCNTs) causes a progressive decrease of the transepithelial electrical resistance (TEER), pointing to a CNT-dependent impairment of the epithelial barrier function. To characterize better this behavior, we compared the effects of two types of MWCNTs and single-walled CNTs (SWCNTs) of different lengths on the TEER of Calu-3 monolayers. All the materials were used at a dose of 100 microg/mL corresponding to an exposure of 73 microg/cm(2) of cell monolayer. Only the longer MWCNTs and SWCNTs cause a significant decrease in TEER. To elucidate the mechanism underlying the changes in barrier function, the expression of the junction proteins occludin and ZO-1 has been also assessed. No significant decrease in the mRNA for either protein is detectable after the exposure to any type of CNTs. It is concluded that the impairment of barrier function in Calu-3 monolayers is a peculiar effect of CNTs endowed with clear cut fiber properties and is not referable to marked changes in the expression of junction proteins.

Nature-inspired indolyl-2-azabicyclo[2.2.2]oct-7-ene derivatives as promising agents for the attenuation of withdrawal symptoms: synthesis of 20-desethyl-20-hydroxymethyl-11-demethoxyibogaine

Microwave assisted Diels-Alder cycloaddition of 5-Br-N-benzylpyridinone (2) with methyl acrylate is described to gain an easy access to 7-bromo-2-benzyl-3-oxo-2-aza-5 or 6-carbomethoxy bicyclo[2.2.2]oct-7-enes (3)-(6). The preparation of the ibogaine analogue 20-desethyl-(20-endo)-hydroxymethyl-11-demethoxyibogaine (17) is described by stereoselective hydrogenation of the C(7)-C(8) double bond. Biological evaluation showed an interesting in vitro binding profile toward dopamine transporter, serotonin transporter and opioid receptor systems accompanied by an antiwithdrawal effect in mice for hydroxymethyl 7-indolyl-2-aza-bicyclo[2.2.2]oct-2-ene (14). The simplification of the ibogaine structure appears as a promising approach toward the design of compounds that could reduce the withdrawal symptoms.

Remote Stereocenter Discrimination in the Enzymatic Resolution of Piperidine-2-ethanol. Short Enantioselective Synthesis of Sedamine and Allosedamine

Kinetic resolution of N-Boc-piperidine-2-ethanol (2), a case of remote stereocenter discrimination, was accomplished by sequential transesterification mediated by two enzymes, Lipase PS and porcine pancreatic lipase, showing opposite enantioselectivity. The gram-scale availability of the two enantiomeric N-Boc alcohols 2a (R) and 2c (S) enlarges their synthetic exploitation for the enantioselective preparation of piperidine alkaloids. As an example, the convenient three-step synthesis of both the enantiomers of sedamine and allosedamine is described.

Alcohol addiction: evaluation of alcohol abstinence after a year of psycho-medical-social treatment

The aim of this study was to evaluate alcohol abstinence in alcoholics and their family relationships after a year of treatment. The 100 alcoholics recruited were divided into two groups: ALC, where treatment consisted of clinical control and meetings of with the family consulting together with their relatives at the Centre for Study and Treatment of Alcoholism and CAT, where treatment consisted of clinical control and weekly attendance together with their relatives at Alcoholics-in-Treatment-Clubs (CAT). The clinical condition of the sample was assessed by laboratory data. The subjects were given an MQ-Quant questionnaire, based on an artificial neural network (ANN) model, which analyses the communicative fatigue of their interactions. The same examination was applied after 1 year excluding patients relapsed and their relatives. Psycho-medical-social treatment by the attendance of alcoholics and their families into a Multifamily Community induces alcohol abstinence of about 79%. This percentage is greater than psycho-medical treatment carried out in the Centre of Alcoholism for ALC group (50%). We observed a significant difference between the communicative fatigue of the ALC group compared to the CAT group.

Sodium sensitivity of blood pressure in long-term detoxified alcoholics

To investigate whether sodium sensitivity of blood pressure participates in the relationship of arterial hypertension to chronic alcohol consumption, 30 alcoholics detoxified from 6 to 12 months and 30 teetotaler controls underwent a dietary sodium manipulation study. They received a daily 55 mmol sodium diet for 7 days, followed by a 260 mmol sodium diet for 7 days. Changes in 24-hour urinary sodium excretion between the end of each period were similar in alcoholics and controls (202+/-16 SEM mmol and 227+/-11, respectively). Plasma renin activity in alcoholics was lower than in controls at both low (2.4+/-0.4 ng angiotensin I/mLxh(-1) versus 3. 7+/-0.2, P<0.003) and high sodium intake (0.47+/-0.10 versus 0. 82+/-0.10, P<0.05), with smaller variations in alcoholics (-1.9+/-0. 3 versus -2.9+/-0.2, P<0.009). In alcoholics, alteration in sodium intake was followed by greater changes in both systolic and mean blood pressure (ambulatory blood pressure monitoring), which rose by 10.6+/-2.2 mm Hg and 7.3+/-1.5 versus 4.7+/-1.4 and 3.9+/-1.0 in controls, respectively (P<0.03 for systolic and P<0.05 for mean blood pressure). The ratio of changes in mean blood pressure to those in 24-hour urinary sodium excretion was higher in alcoholics (0.044+/- 0.011 mm Hgxmmol(-1) versus 0.018+/-0.0041, P<0.005). Our data show that in detoxified alcoholics, there is an abnormal response of both blood pressure and plasma renin activity to variations in salt intake similar to that in sodium-sensitive arterial hypertension. The precise relationship between the sodium sensitivity of blood pressure in detoxified alcoholics and the long-term influence of alcohol on blood pressure remains to be elucidated.

Comparison of the results of immunocytochemical assays for biologic variables on preoperative fine-needle aspirates and on surgical specimens of primary breast carcinomas

BACKGROUND

Fine-needle aspiration biopsy (FNAB) is a well-documented procedure for the diagnosis and biologic characterization of breast carcinoma. In order to compare the immunocytochemical expression of biologic parameters on cytology and on histology, estrogen receptor (ER) and progesterone receptor (PgR) status, p53 protein expression, and Ki67 growth fraction were evaluated on presurgical fine-needle aspirates (FNAs) from breast carcinoma patients and on the corresponding surgical samples prior to any systemic therapy.

METHODS

FNAs were performed on 104 patients with primary breast carcinoma at the time of diagnosis and subjected to immunocytochemical evaluation of ER, PgR, p53, and Ki67. The same parameters were immunohistochemically evaluated on the corresponding paraffin embedded sections.

RESULTS

ER, PgR, p53, and Ki67 were evaluable on FNAs and on paired tissue sections in 100, 97, 68, and 84 cases, respectively. Concordance between cytology and histology was 89% for ER, 78% for PgR, 79% for p53, and 70% for Ki67.

CONCLUSIONS

The concordance between the results of immunocytochemical evaluation of ER, PgR, p53, and Ki67, on both cytology and histology, underscores the reliability of the biologic characterization of breast carcinoma by FNAB. This approach could be particularly useful in predicting prognosis and response to treatment in patients who are candidates for neoadjuvant chemotherapy and/or endocrine therapy.

Patients' opinions, feelings, and attitudes after a campaign to promote the Di Bella therapy

BACKGROUND

An emotional campaign promoting the Di Bella cancer therapy was launched by the Italian media in 1997. Its effects on patients' hopes, feelings, and decision-making processes were largely unknown. We undertook an investigation of this issue.

METHODS

Between Feb 25 and March 31, 1998, a ten-item questionnaire was distributed to 1300 unselected adult patients attending 13 cancer centres throughout Italy. Four expert psycho-oncologists reviewed the design and validity of the contents of the questionnaire. Sociodemographic information was also collected.

FINDINGS

1120 (86%) questionnaires were returned and analysed. The main sources of information were television/radio (62%) and newspapers (26%); only 5% cited doctors. The campaign induced optimism in the patients about the efficacy of the method (ineffective 1%, effective 42%, uncertain 57%), and 53% said their hope of cure was increased. However, 48% felt more confused. 24% do not discuss new treatments with their oncologists, and 20% would like to but cannot. When choosing a treatment, the advice of a trusted doctor was judged more important than scientific progress (53% vs 32%) and 63% would try even unproven treatments in the hope of a cure. Replies to many of the questions were influenced by patients' educational attainment and by the degree of communication with their oncologists.

INTERPRETATION

Science cannot prevent the harm caused by such campaigns and their psychological consequences, particularly for less educated patients. When making decisions, patients are looking for hope from the treatment and trust in their doctor, both of which depend on effective doctor-patient communications that therefore need to be improved.

Can weight gain in healthy, nonobese volunteers be predicted by differences in baseline plasma insulin concentration?

In this study, we have evaluated the effect, over approximately 14 yr, of differences in baseline degree of hyperinsulinemia on weight gain in 647 healthy, nonobese factory workers. The subjects were divided into 4 quartiles, on the basis of their plasma insulin response to an oral glucose challenge, in 1981. At that time, the mean (+/-SD) plasma insulin concentration, 2 h after the glucose challenge, varied from 18+/-5 to 106+/-42 microU/mL. Despite this approximate 6-fold difference in plasma insulin response at baseline, the weight gain over the period of observation was similar in all quartiles, with mean (+/-SD) increments (kg) of 1.8+/-5.1, 1.6+/-5.3, 2.3+/-5.2, and 2.3+/-5.7, going from the lowest quartile to the highest quartile, in terms of insulin concentration. Furthermore, when the population was considered as a whole, there was no correlation between baseline degree of hyperinsulinemia and change in either absolute (r = 0.004) or percent (r = 0.003) weight gain. Finally, there was no difference in the number of individuals who gained more than 4.5 kg, as a function of their baseline insulin response. Consequently, we conclude that 6-fold differences in plasma insulin responses to glucose do not predict weight gain in a healthy, nonobese population.

Dipyridamole-induced ischemia as a prognostic marker of future adverse cardiac events in adult patients with hypertrophic cardiomyopathy. Echo Persantine Italian Cooperative (EPIC) Study Group, Subproject Hypertrophic Cardiomyopathy

BACKGROUND

Myocardial ischemia may play a role in the natural history of hypertrophic cardiomyopathy (HCM). To assess the relative prevalence and the prognostic value of dipyridamole-induced ischemia, 79 patients with HCM and without concomitant coronary artery disease (53 men; mean age, 46+/-15 years) underwent a high-dose (up to 0.84 mg/kg over 10 minutes) dipyridamole test with 12-lead ECG and two-dimensional echo monitoring and were followed up for a mean of 6 years.

METHODS AND RESULTS

Twenty-nine patients (37%) showed ECG (ie, ST depression > or = 2 mV) signs of myocardial ischemia during dipyridamole test (group 1), whereas 50 (63%) had a negative test (group 2). No patient had transient wall motion abnormalities during the dipyridamole test. During the follow-up, 16 events (ie, left ventricular or atrial enlargement, unstable angina, syncope, atrial fibrillation, and bundle-branch block) occurred in 29 patients in group 1 and 5 in 50 patients in group 2 (55% versus 10%, P<.001). Patients with a positive dipyridamole test showed worse 72-month event-free survival rates compared with patients with a negative test (36.2% versus 84.2%, P<.001). A forward stepwise event-free survival analysis identified dipyridamole test positivity by ECG criteria (chi2=19.7, P=.0001), rest gradient (chi2=11.3, P=.0008), and age (chi2=4.1; P=.0413) as independent and additive predictors of subsequent events.

CONCLUSIONS

ECG signs of myocardial ischemia elicited by dipyridamole are frequent in patients with HCM and identify patients at higher risk of cardiac events, suggesting a potentially important pathogenetic role of inducible myocardial ischemia in determining adverse cardiac events in these patients.

Peak aortic blood acceleration: a possible indicator of initial left ventricular impairment in patients with coronary artery disease

In 25 patients undergoing diagnostic cardiac catheterization, a catheter-tip electromagnetic velocity transducer was used to evaluate maximum velocity and acceleration of blood in the ascending aorta. All patients underwent a complete haemodynamic evaluation, including high-fidelity recording of intraventricular pressures and calculation of the derived indices, left ventriculography and coronary angiography. Nineteen patients with critical coronary stenoses were divided according to the presence of signs of left ventricular dysfunction, while the control group consisted of six subjects with chest pain, but without cardiac abnormalities detectable by cardiac catheterization. Maximum aortic acceleration was significantly lower in coronary patients (378 +/- 130 vs 562 +/- 82 in the control group P less than 0.01) and also in the selected subgroup of coronary patients with normal haemodynamic and angiographic indices of left ventricular systolic function (310 +/- 102 vs 562 +/- 82, P less than 0.01). No relationship could be observed between maximal blood acceleration and left ventricular peak systolic pressure, +dP/dt, left ventricular end-systolic volume index and ejection fraction. Our results suggest that maximal blood acceleration from the left ventricle may detect an initial myocardial impairment in patients with definite coronary artery disease but with normal conventional indices of left ventricular function. The clinical interest of this index, however, is limited by overlapping values in patients with and without coronary artery disease and the inability of a further separation of ischaemic patients in accordance with the severity of left ventricular impairment and the extension of coronary artery involvement.

[Modification of left ventricular filling after acute administration of nifedipine in hypertensive patients. Doppler echocardiographic study]

This study was undertaken to determine the acute effects of nifedipine on left ventricular filling, examined by Doppler echocardiography in patients with arterial hypertension and normal left ventricular systolic function. Twenty-seven patients with mild to moderate systemic hypertension, and 18 normotensive subjects were studied. Pulsed Doppler, M-mode and B-mode measurements were performed before and 30 min after sublingual nifedipine administration (10 mg). Peak E, peak A, area A, area E, ratio area A/area E, E deceleration and E acceleration time were measured. Before administering nifedipine, some of these diastolic filling parameters were significantly different in the hypertensive patients as compared with normal subjects. After nifedipine, in patients with arterial hypertension, peak E and area E increased significantly (p less than 0.01), while ratio peak A/E and ratio area A/area E showed a significant decrease (p less than 0.001). No significant changes were observed in normal subjects. The result of this study demonstrates that the acute administration of nifedipine modifies transmitral flow velocity pattern in hypertensive patients, suggesting that the left ventricular filling abnormalities are in part dynamic and reversible.

[Early changes in ventricular function in diastolic phase in the resting coronary patient]

The aim of this study is to test left ventricular diastolic function in coronary artery disease patients with preserved systolic performance. Two groups of patients (25 coronary artery disease patients with angiographic proved coronary artery stenosis, but with normal hemodynamic and angiographic indices of systolic phase, first group; and 14 normal subjects for control, second group) were tested comparing their systolic and diastolic ventricular function indices, obtained by using a Millar microtip catheter and a computerized program. Systolic ventricular function was similar in the two groups (EF: 0.61 +/- 0.05 vs 0.62 +/- 0.03, p: n.s.; Vmax:120 +/- 28 vs 112 +/- 24 sec-1, p: n.s.), while diastolic indices were significantly different (lowest diastolic pressure: 3.7 +/- 2.4 vs -1.72 +/- 1.45 mmHg, p less than 0.01; end-diastolic pressure: 11.2 +/- 4.2 vs 6.5 +/- 2.8 mmHg, p less than 0.05; T constant: 45 +/- 8 vs 35 +/- 6 mmHg, p less than 0.001; end-diastolic compliance: 2.79 +/- 0.3 X 10(-2) vs 5.68 +/- 0.4 X 10(-2) mmHg-1, p less than 0.001; Kp: 0.041 +/- 0.006 vs 0.003 +/- 0.004 p less than 0.001). In conclusion, impairment of left ventricular diastolic phase may be one of the earliest manifestations of functional alterations of ischemic ventricle.