Alström syndrome is associated with short stature and reduced GH reserve

INTRODUCTION

Alström syndrome (ALMS) is a rare autosomal recessive monogenic disease included in an emerging class of genetic disorders called 'ciliopathies' and is likely to impact the central nervous system as well as metabolic and endocrine function. Individuals with ALMS present clinical features resembling a growth hormone deficiency (GHD) condition, but thus far no study has specifically investigated this aspect in a large population.

MATERIAL AND METHODS

Twenty-three patients with ALMS (age, 1-52 years; 11 males, 12 females) were evaluated for anthropometric parameters (growth charts and standard deviation score (SDS) of height, weight, BMI), GH secretion by growth hormone-releasing hormone + arginine test (GHRH-arg), bone age, and hypothalamic-pituitary magnetic resonance imaging (MRI). A group of 17 healthy subjects served as controls in the GH secretion study. Longitudinal retrospective and prospective data were utilized.

RESULTS

The length-for-age measurements from birth to 36 months showed normal growth with most values falling within -0·67 SDS to +1·28 SDS. A progressive decrease in stature-for-age was observed after 10 years of age, with a low final height in almost all ALMS subjects (>16-20 years; mean SDS, -2·22 ± 1·16). The subset of 12 patients with ALMS tested for GHRH-arg showed a significantly shorter stature than age-matched controls (154·7 ± 10·6 cm vs 162·9 ± 4·8 cm, P = 0·009) and a mild increase in BMI (Kg/m(2) ) (27·8 ± 4·8 vs 24·1 ± 2·5, P = 0·007). Peak GH after GHRH-arg was significantly lower in patients with ALMS in comparison with controls (11·9 ± 6·9 μg/l vs 86·1 ± 33·2 μg/l, P < 0·0001). Severe GHD was evident biochemically in 50% of patients with ALMS. The 10 adult ALMS patients with GHD showed a reduced height in comparison with those without GHD (149·7 ± 6·2 cm vs 161·9 ± 9·2 cm, P = 0·04). MRIs of the diencephalic and pituitary regions were normal in 11 of 12 patients. Bone age was advanced in 43% of cases.

CONCLUSIONS

Our study shows that 50% of nonobese ALMS patients have an inadequate GH reserve to GHRH-arg and may be functionally GH deficient. The short stature reported in ALMS may be at least partially influenced by impairment of GH secretion.

Brain involvement in Alström syndrome

BACKGROUND

Alström Syndrome (AS) is a rare ciliopathy characterized by cone-rod retinal dystrophy, sensorineural hearing loss, obesity, type 2 diabetes mellitus and cardiomyopathy. Most patients do not present with neurological issues and demonstrate normal intelligence, although delayed psychomotor development and psychiatric disorders have been reported. To date, brain Magnetic Resonance Imaging (MRI) abnormalities in AS have not been explored.

METHODS

We investigated structural brain changes in 12 genetically proven AS patients (mean-age 22 years; range: 6-45, 6 females) and 19 matched healthy and positive controls (mean-age 23 years; range: 6-43; 12 females) using conventional MRI, Voxel-Based Morphometry (VBM) and Diffusion Tensor Imaging (DTI).

RESULTS

6/12 AS patients presented with brain abnormalities such as ventricular enlargement (4/12), periventricular white matter abnormalities (3/12) and lacune-like lesions (1/12); all patients older than 30 years had vascular-like lesions. VBM detected grey and white matter volume reduction in AS patients, especially in the posterior regions. DTI revealed significant fractional anisotropy decrease and radial diffusivity increase in the supratentorial white matter, also diffusely involving those regions that appeared normal on conventional imaging. On the contrary, axial and mean diffusivity did not differ from controls except in the fornix.

CONCLUSIONS

Brain involvement in Alström syndrome is not uncommon. Early vascular-like lesions, gray and white matter atrophy, mostly involving the posterior regions, and diffuse supratentorial white matter derangement suggest a role of cilia in endothelial cell and oligodendrocyte function.

Alström syndrome: cardiac magnetic resonance findings

BACKGROUND

Alström Syndrome (ALMS) is an extremely rare multiorgan disease caused by mutations in ALMS1. Dilated cardiomyopathy (DCM) is a common finding but only one series has been investigated by Cardiac Magnetic Resonance (CMR).

METHODS

Eight genetically proven ALMS patients (ages 11-41) underwent CMR performed by standard cine steady state, T1, T2 and late gadolinium enhancement (LGE) sequences. Ejection fraction (EF), Diastolic Volume (EDV) and Systolic Volume normalized for body surface area (ESV), and mass indices were determined, as well as EDV/Mass ratio, an index expressing the adequacy of cardiac mass to heart volume. Regional fibrosis was assessed by LGE; diffuse fibrosis was measured by a TI scout sequence acquired at 5, 10 and 15 min after gadolinium by comparing inversion time values (TI) at null time in ALMS and control group.

RESULTS

In one patient severe DCM was present with diffuse LGE. There were seven cases without clinical DCM. In these patients, EF was at lower normal limits or slightly reduced and ESV index increased; six patients had decreased mass index and EDV/Mass ratio. Mild regional non ischemic fibrosis was detected by LGE in three cases; diffuse fibrosis was observed in all cases, as demonstrated by shorter TI values in ALMS in comparison with controls (5 min: 152 ± 12 vs 186 ± 16, p 0.0002; 10 min: 175 ± 8 vs 204 ± 18, p 0.0012; 15 min: 193 ± 9 vs 224 ± 16, p 0.0002).

CONCLUSIONS

Cardiac involvement in ALMS is characterized by progressive DCM, associated with systolic dysfunction, myocardial fibrosis and reduced myocardial mass.

The progression from obesity to type 2 diabetes in Alström syndrome

BACKGROUND

Alström syndrome (ALMS) is a rare autosomal recessive monogenic disease associated with obesity, hyperinsulinemia, and alterations of glucose metabolism that often lead to the development of type 2 diabetes at a young age.

OBJECTIVE

To study the relationship between weight and metabolism in a group of ALMS patients and matched controls.

RESEARCH DESIGN AND METHODS

Fifteen ALMS patients (eight males, seven females; aged 3-51) were compared in a cross-sectional study with an age- and weight-matched control population. Anthropometric parameters, fat mass, glucose and insulin secretion in basal and dynamic oral glucose tolerance test (OGTT) conditions were measured. Furthermore, anthropometric and body composition data were obtained from an international group of 27 ALMS patients (13 males, 14 females, age range: 4-29 yr).

RESULTS

In ALMS we observed an inverse correlation between age and standard deviation scores for height, weight, and body mass index. The OGTT glycemic curves of ALMS subjects were similar to those of age-matched controls, whereas insulin response was clearly greater. In ALMS individuals the insulin response showed a reduction with age. We documented pathologic values of the derived indices homeostasis model assessment of insulin resistance (HOMA-IR), insulin sensitivity index, HOMA%β-cell and insulinogenic index in ALMS, but unlike the insulin-resistance indices, the β-cell function indices showed a significant reduction with age.

CONCLUSIONS

In ALMS the progression from the early onset obesity toward the impaired fasting glucose or impaired glucose tolerance and overt diabetes is mostly because of a progressive failure of β-cell insulin secretion without any further worsening of insulin resistance with age, even in the presence of weight reduction.

Detection of HCV and GBV-C/HGV infection by multiplex PCR in plasma samples of transfused subjects

A multiplex polymerase chain reaction (PCR) was applied to clinical samples for simultaneous detection of hepatitis C virus (HCV) and GBV-C/HGV genome. With both RNA viruses, the amplification was performed with primers of the 5' UTR region starting from the single viral RNA reverse transcripted (cDNA) with random hexanucleotide primer mix. GBV-C/HGV RNA was detected in plasma sample of seven out of 50 transfused patients (14%). The multiplex PCR demonstrated a sensitivity up to 7.8 x 10(2) copies/ml respectively for GBV-C/HGV and HCV RNA in plasma samples of 5/50 patients with GBV-C/HGV/HCV co-infection and in patients with HCV (27/50) or GBV-C/HGV infection alone (2/50).

Effect of middle-intensity exercise on carnitine and beta-hydroxybutyrate plasmatic concentration in men and women

The purpose of this study is to describe the dynamics of carnitine, its esters and beta-hydroxybutyrate, during a prolonged moderate-intensity physical exercise, as the literature data (Angelini 1986, Carlin 1986, Lennon 1984) up to date reported were not uniform. In our study twenty-two untrained subjects (11 males, 11 females) performed a test exercise on a motor-driven treadmill for 90 min at 50-60% of VO2 max. Blood samples were obtained at rest, at 20, 40, 60 and 90 min during the exercise and after 30 min of recovery. Men show an increase over rest values in short chain acyl carnitine after 90 min of exercise higher than women (M 157%, F 80%), while women have a more elevated relative increase in beta-hydroxybutyrate (M 201%, F 233%); Total carnitine in both sexes is not significantly modified.

Expression and localization of polygalacturonase during the outgrowth of lateral roots in Allium porrum L

The presence of polygalacturonase and its correlation with the formation of lateral roots in leek (Allium porrum L.) seedlings have been investigated. During root growth, a steady increase in polygalacturonase activity was associated with that of the lateral root primordia. Fractionation of root extract by fast protein liquid chromatography resolved at least two polygalacturonase isoforms. One of the isoforms, a 75-kdalton protein, strongly reacted on Western blots probed with a polyclonal antibody raised against tomato polygalacturonase. It also reacted with both polyclonal and monoclonal antisera raised against Fusarium moniliforme polygalacturonase. In situ localization with these three antibodies showed that polygalacturonase was present over the meristems of lateral root primordia. Antibodies against pectins (Knox et al. 1990, Planta 181, 512-521) detected large amounts of pectic material filling the area between the apex of the primordium and the mother root tissues. We suggest that a polygalacturonase plays an important role in leek root morphogenesis, particularly during lateral root outgrowth.

[The role of intra- and extracellular Ca++ in coronary vessel contraction induced in vitro by noradrenaline following a beta-adrenergic block]

Previous studies reported that norepinephrine (NE) induces contraction of the calf isolated coronary arteries after beta-adrenergic blockade with propranolol (PR), and that the effect disappeared after phentolamine. An higher Ca++ concentration increased the response of preparation to NE, whereas the reduction of the concentration reduced the response. In isolated coronary arteries the baseline tone and contractile response to NE after PR were studied as influenced by DA and nicardipine (NI). NI always induced vessel relaxation and DA induced a contraction followed by relaxation. The NE contraction was not abolished in calcium-free medium but in presence of DA and was reduced by NI in the medium containing Ca++. We conclude that NE induces contractions by facilitating the influx of the extracellular Ca++ and by promoting the liberation of intracellular bound Ca++.

Vagal stimulation and exogenous acetylcholine in isolated rat stomach: calcitonin effect on contractile activity

Calcitonin induces contraction in the vascular and extravascular smooth muscle and facilitates the transmission of the excitation in somatic motor nerve endings. These actions are Ca2(+)-dependent. The calcitonin effect on autonomic nerve endings has been studied here by testing influence of calcitonin on the contractile responses of the isolated rat stomach. The organ was submitted to electrical vagal stimulation or, after denervation, to exogenous acetylcholine. Calcitonin invariably increased the muscular tone and reduced the contractile responses to vagal stimulation. Opposite effects were noted after a serotoninergic block with nicergoline. Calcitonin also increased the contractile response evoked by exogenous acetylcholine and the Ca(2)-antagonist nicardipine counteracted the facilitatory effects. We suggest that the inhibitory action of calcitonin is serotonine-dependent while the facilitatory one is Ca2(+)-dependent.

[Mechanical responses on isolated frog neuromuscular preparations in the presence of calcitonin]

Previous observations had shown that, in the isolated rat preparations, calcitonin facilitates the excitement transmission from autonomic nerve-endings to smooth muscle. The present research, was designed to verify whether this facilitation effect could be present in somatic nerve-endings too. For this reason, we used the isolated frog "sciatic nerve-gastrocnemius muscle" preparation where the calcitonin influence on the beginning of a complete tetanic response was studied. The motor nerve-endings were stimulated at different frequencies. It was observed that the added calcitonin and/or an increased [Ca++] medium induced a complete tetanic response also at stimulating frequencies that, in the controls, provoked only a clonic response. Moreover, both the calcitonin and the increased [Ca++] medium frequently induced an increase in the mechanical muscle tension developed. These facilitating effects were reduced or even abolished with inhibition of Ca++-passage through the cell membrane by nifedipine. Therefore, we could hypothesize that the added calcitonin causes increased Ach-release from the somatic nerve-endings and that this action depends on facilitated Ca++-passage through the cell membrane of the nerve-endings and of the muscle fibres too.

[Cholinomimetics effects of carnitine on isolated and denervated rat stomach preparations]

According to various suggestions in the literature of cholinomimetic effects of carnitine on nervous structures, and experimental results of previous work on vascular smooth muscle, we studied the influence of this substance on the rat isolated and denervated stomach responses to acetylcholine (Ach). We found that Ach invariably induces contraction of the preparation, this effect being abolished by means of atropine or prifinium bromide or reduced by means of fendiline or flunarizine. We found also that carnitine invariably enhances the contractile responses of the preparation to Ach, and this effect is not modified by indomethacin or lysine acetylsalicylate, but usually abolished by fendiline and flunarizine. Our opinion is that the potentiation of stomach contractile responses to Ach by carnitine, is not due to prostaglandin mediation but it is due to sensitisation of the muscarinic receptors, which are stimulating contraction (here and in vascular smooth muscle) by means of: facilitation of calcium transit across the cellular membrane; intracellular deposit site release activation.

[Effect of a bioflavinoid (4-methylesculetin) on the response of calf hepatic arteries to serotonin in the presence of indomethacin]

The aim of this work is to study the mechanism by which 4-methylsculetin (4-Me) inhibits the serotonin induced contraction in smooth muscle. The effect of 4-Me, alone or associated with ascorbic acid, on basal tone and serotonin induced contraction of isolated hepatic artery strips have been studied. Experiments have been carried out in the presence of indomethacin (IN), specific inhibitor of prostaglandin-synthetase. IN suppressed the depressive effect of 4-Me on the serotonin dependent contraction. Therefore, it seems reasonable to conclude that the 4-Me influence could be mediated by prostaglandins release smooth muscle.

[Response of isolated coronary artery segments to serotonin in the presence of a flavinoid, indomethacin and acetylsalicylate]

The aim of this work is to study the mechanism by which 4-metilesculetin (4-Me) cause the relaxation or inhibit the serotonin induced contraction in the smooth muscle. The effect of 4-Me, alone or associated with ascorbic-acid, on basal tone and serotonin induced contraction of isolated coronary strips have been studied. Experiments have been carried out in the presence of indomethacin (IN), specific inhibitor of prostaglandin synthetase. IN-decreased, but did not abolished, the 4-Me induced relaxation and reduced or suppressed the depressive effect of 4-Me on the serotonin dependent contraction. Therefore, it seems reasonable to conclude that the 4-Me influence could be mediated by prostaglandins release in the smooth muscle.

[Effect of a flavinoid (4-methylesculetin) on the response of isolated calf coronary arteries to histamine in the presence of indomethacin]

The aim of this work is to study the mechanism by which 4-methylesculetin (4-Me) cause the relaxation or inhibit the histamine induced contraction in the smooth muscle. The effect of 4-Me, alone or associated with ascorbic-acid, on basal tone and histamine induced contraction of isolated coronary strips have been studied. Experiments have been carried out in the presence of indomethacin (IN), specific inhibitor of prostaglandin synthetase. IN-decreased, but did not abolished, the 4-Me induced relaxation and reduced or suppressed the depressive effect of 4-Me on the histamine dependent contraction. Therefore, it seems reasonable to conclude that the 4-Me influence could be mediated by prostaglandins release in the smooth muscle.

[Responses of isolated hepatic artery segments to barium in the presence of a flavonoid (4-methylesculetin), indomethacin and acetylsalicylate]

The aim of this work is to study the mechanism by which 4-methylesculetin (4-Me) inhibits the Ba++ induced contraction in smooth muscle. The effect of 4-Me, alone or associated with ascorbic acid, on basal tone and Ba++ induced contraction of isolated hepatic artery strips have been studied. Experiments have been carried out in the presence of lysine acetylsalicylate (LAS) and indomethacin (IN), specific inhibitors of prostaglandin-synthetase. Both LAS and IN suppressed the depressive effect of 4-Me on the Ba++ dependent contraction. Therefore, it seems reasonable to conclude that the 4-Me influence could be mediated by prostaglandins release smooth muscle.

[Ca++ dependence of the contraction of coronary artery segments in response to norepinephrine after beta-adrenergic blockade]

The effect of external calcium concentration on the NE-induced contraction after beta-adrenergic blocking was studied in vitro. It resulted that the effect of NE was enhanced by increase, or reduced by decrease of calcium concentration. NE-induced contraction was not abolished when the bathing fluid was Ca++-free. The disappearance of the NE effect was only obtained in preparations treated with EDTA and perfused with Ca++-free Ringer-Locke solution. It is concluded that NE induced contraction after beta-adrenergic blocking is Ca++-dependent and on the tissue bound Ca++.

[Response of isolated segments of hepatic arteries to serotonin in the presence of methergoline]

The effect of metergoline (an anti 5-HT drug) on strips of calf hepatic arteries was investigated. Metergoline prevents or antagonizes the contraction induced by 5-Hydroxytryptamine. The inhibitory effect is dose-dependent.

[Analysis of flexion energy variations of a human red blood cell, of ellipsoid form, in the process of deformation imposed by turbulent tangential flux]

The purpose of the present, morphological analysis is to recognize a functional connection between shear stress tau, which Human Red Cells, treated with glutaraldehyde, are subjected and their energy of bending (U), during the shape transition, turbulent shear-flow dependent, under the hypothesis of "isoareal" transformation. The experimental basis of this analysis is the work of Sutera and Mehrjardi.

[Inhibitory effect of methergoline on serotonin induced contraction of isolated strips of coronary arteries]

Metergoline (antiserotonin drug) prevents the contraction induced by serotonin on strips of isolated coronary arteries. Moreover when metergoline is added at the maximal contraction, it induces relaxation of the vascular smooth muscle preceeded by a brevious phase of contraction.

[Influence of bioflavonoid (4-methylesculetin) on the reaction of isolated calf hepatic artery to serotonin]

The effect of 4-metilesculetin on strips of calf hepatic arteries was investigated. 4-metilesculetin antagonizes the contraction induced by 5-HT probably through activation of the synthesis of vasodilator prostaglandins.

[Response of isolated coronary artery strips to noradrenaline in the presence of desoxycorticosterone]

The effect of desoxycorticosterone on the noradrenaline-induced relaxation of coronary arteries was studied "in vitro". It resulted that the effect of noradrenaline was enhanced by desoxycorticosterone. It is concluded that desoxycorticosterone potentiates the effects of noradrenaline by inhibiting its inactivation by Catechol-O-methyltransferase.

[Influence of desoxycorticosterone on the response of coronary artery segments to adrenaline in the presence of pyrogallol]

The effect of desoxycorticosterone on the adrenaline-induced relaxation of coronary arteries was studied in vitro, after a known inhibitor of COMT, pyrogallol. Relaxation induced by adrenaline was enhanced by desoxycorticosterone. Relaxation in response to adrenaline was increased by desoxycorticosterone. Pyrogallol potentiated the responses of coronary strips to adrenaline and also reduced or abolished the enhancing effects of desoxycorticosterone. It is concluded that desoxycorticosterone enhances the response of coronary smooth muscle to adrenaline by inhibiting an enzymatic pathway for the inactivation of catecholamines.

[Influence of desoxycorticosterone on the response of calf coronary artery strips to adrenaline]

The effect of desoxycorticosterone on the adrenaline-induced relaxation of coronary arteries was studied "in vitro". It resulted that the effect of adrenaline was enhanced by desoxycorticosterone. It is concluded that desoxycorticosterone potentiates the effects of adrenaline by inhibiting its inactivation by Catechol-O-methyltransferase.

[Angiotensin II-acetylcholine interaction on the mechanical response of the isolated rat stomach]

This research was carried on denervated isolated rat stomach. Mechanical response to Ach treated with three different ATN II concentrations was recorded. No competitive antagonism was observed so that no common receptor can be supposed. The apparent noncompetitive antagonism may be ascribed to the action of ATN II on P and T Ca++ activating systems.

[Influence of hydrocortisone on the response to noradrenaline of segments of isolated coronary arteries in the presence of a beta-adrenergic blocking agent]

The effect of hydrocortisone on the noradrenaline-induces contraction, after propranolol, was studied in vitro. Contraction of response to noradrenaline were increased by hydrocortisone. We suggest that the hydrocortisone influence depends on inhibition of catecol-O-metiltransferase (COMT).

[Influence of dexamethasone on the responses of isolated coronary arteries to adrenaline]

The effect of Dexamethasone on the adrenaline-induced relaxation was studied in vitro. Relaxation of response to adrenaline increased by Dexamethasone. We suggest that the Dexamethasone influence depends on inhibition of Catecol-O-methyl transferase (COMT).

[Influence of 6-methylprednisolone on responses of isolated coronary arteries to adrenaline]

The effect of 6-Methylprednisolone on the adrenaline-induced relaxation was studied in vitro. Relaxation of response to adrenaline increased by 6-Methylprednisolone. We suggest that the 6-Methylprednisolone influence influence depends on inhibition of Catecol-O-methyl transferase (COMT).

[Effect of acetylcholine "in vitro" on segments of isolated coronary arteries of calves]

The mechanical responses of coronary arteries to Ach were studied in vitro. Ach caused always a contraction of the preparation, which was prevented or abolished by Athropine but not by Exametonium. Therefore Ach seems to act through muscarinic receptors.

[Influence of variations of Ca++ on responses of segments of the isolated coronary artery to acetylcholine]

The effect of external calcium concentration on the Ach-induced contraction of coronary arteries was studied in vitro. It resulted that the effect of Ach was enhanced by the increase, or reduced by the decrease of calcium concentration. It is concluded that, as it was known for the intestinal smooth muscle, also for the smooth muscle of the coronary arteries, the contractile effect of Ach is dependent on the calcium of the medium.

[Preliminary note on a model of cup-shaped deformed human erythrocyte]

We have developed a very elementary model for the cup shaped erythrocyte, in order to obtain some geometrical informations about the cellular contour and mould of the membrane, with regard to the territories of the cell, less accessible to the microscopical observation.

[Influence of pyridoxal-5'-phosphate on the responses of isolated coronary arteries to adrenaline, in the presense of pyrogallol]

The effect of PLP on the adrenaline-induced relaxation of coronary arteries was studied in vitro, after known inhibitor of COMT, Pyrogallol. Relaxation of response to adrenaline were increased by PLP. Pyrogallol potentiated responses of coronary strips to adrenaline and also reduced or abolished the enhancing effects of PLP. It is concluded that PLP enhances the response of coronary smooth muscle to adrenaline by inhibiting a enzymatic pathway for the inactivation of catecholamines.