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Premature aging-like phenotype in fibroblast growth factor 23 null mice is a vitamin D-mediated process.

Fibroblast growth factor 23 null mice (Fgf-23-/-) have a short lifespan and show numerous biochemical and morphological features consistent with premature aging-like phenotypes, including kyphosis, severe muscle wasting, hypogonadism, osteopenia, emphysema, uncoordinated movement, T cell dysregulation, and atrophy of the intestinal villi, skin, thymus, and spleen. Furthermore, increased vitamin D activities in homozygous mutants are associated with severe atherosclerosis and widespread soft tissue calcifications; ablation of vitamin D activity from Fgf-23-/- mice, by genetically deleting the 1alpha(OH)ase gene, eliminates atherosclerosis and ectopic calcifications and significantly rescues premature aging-like features of Fgf-23-/- mice, resulting in prolonged survival of Fgf-23-/-/1alpha(OH)ase-/- double mutants. Our results indicate a novel role of Fgf-23 in developing premature aging-like features through regulating vitamin D homeostasis. Finally, our data support a new model of interactions among Fgf-23, vitamin D, and klotho, a gene described as being associated with premature aging process.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗

Alpha-1-antitrypsin deficiency: a review; 1963-1975.

Alpha-1-antitrypsin (A1AT) deficiency originally was recognized as a biochemical abnormality in patients with pulmonary emphysema. Studies of the protein nature of A1AT during attempts to help explain the disease, led to the recognition of a protein polymorphism which expressed itself in several different phenotypes. As investigative work progressed, the spectrum of diseases associated with a deficiency of A1AT increased. Methods for determination of quantitative levels have been developed but these have proved lacking for the discrimination of the various phenotypes, for which specialized testing is necessary. Of the clinical states associated with deficiencies of A1AT, pulmonary emphysema and hepatic disease are the best defined. Pathogenetic implications, however, remain elusive. As a consequence, preventive aspects are debatable and the usefulness of the determination of A1AT levels as screening measures is controversial.

Deficiency Diseases↗

Commercial plasma alpha1-antitrypsin (Prolastin) contains a conformationally inactive, latent component.

Fractionated plasma alpha1-antitrypsin is widely-used as replacement therapy in patients with Z alpha1-antitrypsin deficiency-related emphysema. We have recently shown that purified antitrypsin may be induced to adopt an inactive latent conformation by heating at high temperatures in stabilizing concentrations of sodium citrate. Such a conformation was predicted to be present in commercial preparations of antitrypsin, as these require heating under similar conditions for viral inactivation. Native antitrypsin was purified from plasma, and commercial antitrypsin (Prolastin) was obtained from Bayer Corporation. Western blot analysis of transverse urea gradient (TUG) gels showed that commercial antitrypsin migrated as two bands: one with an unfolding profile of native antitrypsin and the second with a profile of latent antitrypsin. A latent fraction, comprising approximately 8% of the total antitrypsin, was separated from the native antitrypsin in Prolastin by anion exchange chromatography. The specific activity of this latent form against bovine alpha-chymotrypsin increased from 1 to 2% to 50% over 3 h after refolding from 6 M guanidine hydrochloride. These data show that commercial antitrypsin contains a latent component. The significance of this conformation in vivo is unknown, although Prolastin has shown few adverse side-effects in prolonged clinical usage.

Animals↗

[Severe alpha 1-antitrypsin deficiency: cross sectional clinical study].

The aim of this study was to investigate a group of severe alpha 1-antitrypsin deficient subjects. Of the 20 subjects detected, 7 were classified as Index Cases (discovered because they were symptomatic and had pulmonary emphysema or liver disease), while 13 were classified as Non-Index Cases (asymptomatic and discovered because they were relatives of Index Cases or because of the absence of alpha 1 band in serum electrophoresis). They underwent pulmonary function tests, determination of arterial blood gases, lung high resolution computed tomography and lung perfusion scan. All Index Cases were with the ZZ phenotype, indicating a major risk of developing related pulmonary emphysema or liver disease; most Index Cases (71%) were ex-smokers, while among the Non-Index Cases, 46% were smokers or ex-smokers, suggesting that smoking might be the main cofactor in the development of emphysema. Index Cases were older (statistical significance) and mostly male as compared with Non-Index Cases. A statistical significance was observed between the two groups for several lung function parameters (forced expiratory volume in one second, Tiffenau index, residual volume, diffusing capacity of the lung for carbon monoxide, arterial oxygen tension) as a result of a pathological impairment in Index Cases. This underdiagnosed condition merits more attention in order to prevent its complications and to get a better understanding about its diagnosis and management.

Adult↗

Alpha 1-antitrypsin phenotypes and obstructive lung disease in the city of Oslo.

In a community survey in Oslo, Norway, comprising 1268 persons, alpha 1-antitrypsin concentration in serum (AT) and protease-inhibitor (Pi) phenotypes were examined in 1258 subjects. Estimated percentage distribution of Pi-phenotypes in the target population aged 15--70 years was M 87.30%, MS 4.65%, MZ 4.73%, FM 2.69%, SZ 0.13%, IM 0.20%, FZ 0.07%, S 0.06%, FS 0.07% and Z 0.06%. The distribution curve of AT had a normal (Gaussian) shape and the ranges of AT demonstrated great overlap of types MS and MZ with type M. In subjects with phenotype MZ neither respiratory symptoms nor physicians' diagnoses of chronic obstructive lung disease (COLD) were more frequent than in M subjects. Physicians' diagnoses of COLD were slightly more frequent (0.06 greater than P greater than 0.01) in subjects with phenotype MS than M, probably due to there being more smokers in the MS group. Spirometric variables given as per-cent of predicted values yielded large differences between smokers and non-smokers but no differences among phenotypes M, MS and MZ. Radiologic signs of hypertransradiancy and/or emphysema were evently distributed in M, MS and MZ subjects. The only subject observed with Pi-type Z and one out of three subjects with type SZ had COLD. In neither smokers nor non-smokers is phenotype MZ a risk factor of clinical importance for development of obstructive lung disease.

Adolescent↗

The epidemiology of alpha 1-antitrypsin deficiency.

Alpha 1-protease inhibitor can exist as over 70 different biochemical variants (the Pi system) which are inherited as autosomal-codominant alleles. The majority of these variants are of no clinical significance. Epidemiologically, the most abundant are Pi types M, S, and Z. Homozygotes of type Z have only 10%-20% of the normal serum concentration of the inhibitor and have an increased risk of developing pulmonary emphysema. Cigarette smoking is the most important risk factor. A minority of Pi Z homozygotes (10%-20%) develop a form of neonatal hepatitis and a proportion of these suffer from liver cirrhosis in adult life. Heterozygotes of Pi type SZ have about one third of the normal serum alpha 1-protease inhibitor concentration but this phenotype does not in itself appear to be a significant emphysema risk factor. Heterozygotes of Pi type MZ are thought to have a moderately increased risk of developing emphysema but only if they smoke; there is also evidence for an increased risk of cirrhosis among subjects of type MZ. No excessive risk appears to be attached to the MS phenotype. Cumulative survival curves have suggested that type Z homozygotes have a poor prognosis but such estimates are based on clinic or hospital patients who already have respiratory symptoms. Calculations based on population frequencies however, suggest that about 90% of the total number of type Z subjects are not accounted for in such surveys. Their whereabouts remains unclear at present; some will undoubtedly have died of liver or lung disease but it is possible that the majority escape and live undetected among the general population.

Asthma↗

Genetic epidemiology of alpha-1 antitrypsin deficiency in southern Europe: France, Italy, Portugal and Spain.

Alpha-1-antitrypsin deficiency (AAT deficiency) is one of the most common serious hereditary disorders in the world because it affects all major racial subgroups worldwide and there are at least 120.5 million carriers and deficient subjects worldwide. This genetic disease is related to a high risk for development of jaundice in infants, liver disease in children and adults, and pulmonary emphysema in adults. Moreover, AAT-deficiency carrier phenotypes (PiMS and PiMZ) and deficiency-allele phenotypes (PiSS, PiSZ, and PiZZ) are suspected to make subjects susceptible to a variety of other adverse health effects. As there is a limited database on the number of individuals affected by this disease worldwide, the authors of the present report collected data on control cohorts in genetic epidemiological studies published in the peer-reviewed literature worldwide. The data collected were used to estimate the numbers of carriers and deficiency-allele combinations for the two most common defective alleles, namely PiS and PiZ, in over 58 countries worldwide. The present report focuses on the distribution of the PiS and PiZ deficiency alleles in France, Italy, Portugal, and Spain. The total number of individuals at risk for adverse health effects were as follows: 9, 101, 739 in France; 4, 289, 566 in Italy; 2, 659, 241 in Portugal; and 8, 903, 773 in Spain. The geographical distribution of individual control cohorts and estimates of the numbers of carriers and deficiency-allele phenotypes in each of these four southern European countries are shown in individual tables and maps. This report will be followed by other reports on the remaining countries in Europe, as well as worldwide.

Europe↗

Protease inhibitors in chronic obstructive pulmonary disease.

Quantification of the major plasma protease inhibitors and genetic typing of alpha1-antirypsin were done in 107 patients with chronic obstructive pulmonary disease and in 91 control subjects with normal ventilatory function who were similar with respect to age, race, and sex. There was a significant increase in frequency of the PiZ gene and the Pi MZ phenotype of alpha1-antitrypsin among the patients when compared with the control subjects. No evidence for a primary deficiency of any other antiprotease was found; however, the mean concentration of inter-alpha-trypsin inhibitor was significantly lower in the patients than the control subjects, and moderate deficiency of alpha1-antichymotrypsin was noted in a few patients. These data indicate an increased risk of developing chronic obstructive pulmonary disease in persons with the Pi MZ phenotype of alpha1-antirypsin and suggest a possible relationship between these diseases and low serum concentrations of inter-alpha-trypsin inhibitor.

Adult↗

Troglitazone improves endothelial function and augments renal klotho mRNA expression in Otsuka Long-Evans Tokushima Fatty (OLETF) rats with multiple atherogenic risk factors.

Targeted disruption of the klotho gene induces multiple phenotypes characteristic of human aging, including arteriosclerosis, pulmonary emphysema and osteoporosis. Moreover, we previously observed that insufficient klotho expression in mice leads to endothelial dysfunction. In the present study, we used Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which exhibit hypertension, obesity, severe hyperglycemia and hypertriglyceridemia, and are thus considered an animal model of atherogenic disease, to test the effects of oral administration of troglitazone (200 mg/kg) on renal klotho mRNA expression and endothelial function. Systolic blood pressure, body weight, plasma glucose and triglyceride levels were all significantly higher in 30-week-old OLETF rats than in controls (LETO; Long-Evans Tokushima Otsuka) (p<0.05, n=7). In addition, endothelium-dependent relaxation of the aorta in response to 10(-5) M acetylcholine was significantly attenuated in OLETF rats (p<0.05, n=7), as was renal expression of klotho mRNA. Administration of troglitazone for 10 weeks significantly reduced systolic blood pressure, plasma glucose and triglyceride levels in OLETF rats, while augmenting endothelium-dependent aortic relaxation and renal klotho mRNA expression. These findings suggest that troglitazone protects the vascular endothelium against damage caused by the presence of multiple atherogenic factors.

Animals↗

Nutritional status and airflow obstruction: two independent contributors to CO diffusing capacity impairment in COPD.

BACKGROUND: The association between weight loss and Chronic Obstructive Pulmonary Disease (COPD) has been recognised from many years. Based on the evidence that nutritional status reflects metabolic disturbances in COPD, the relationship between body mass index (BMI), severity of airflow obstruction and CO diffusing capacity (DL(CO)), that is the functional hallmark of emphysema, is relevant to the management of COPD phenotypes. METHODS: We reviewed 104 patients with COPD (82 males), aged 66 +/- 9 years (mean +/- SD). Height averaged 165 +/- 8 cm, weight 71 +/- 16 Kg, FEV1 50 +/- 18 (% of predicted), RV 169 +/- 49%, and DL(CO) 56 +/- 26%. Multiple linear regression was performed using BMI, FEV1 and RV, as explanatory variables for DL(CO). Patients were also classified into four groups according to BMI < or = 18.5 (low), > 18.5 and < or = 25 (ideal), > 25 and < or = 30 (overweight), > 30 (obese), and post-bronchodilator FEV1 < 50%. Using this categorisation, a two-factor analysis of variance, testing for interaction and main effects (BMI and FEV1) was performed as confirmatory analysis for the association between BMI (kg/m2), FEV1% and DL(CO)%. RESULTS: FEV1 and BMI were significantly and independently associated to DL(CO) according to the equation: DL(CO) = -18.32 + 0.65 x FEV1 + 1.59 x BMI (R2 = 0.40, p < 0.0001). The contribution of RV % to DL(CO) % was largely non-significant (p = 0.16). A close relationship was found between BMI (kg/m2) and DL(CO) %, for all of the four BMI groups segregated by post-bronchodilator FEV1 %, (p < .0001). No interaction was found between these two factors (p = 0.30). CONCLUSION: Nutritional status as assessed by BMI contributes substantially to impairment of DL(CO) independently of the severity of airflow obstruction. This data confirms the association between emphysematous process and weight loss in advanced COPD, independent of the airflow obstruction severity.

Adult↗

[Alpha 1-antitrypsin deficiency: the Brescia clinical study].

In a longitudinal clinical study, two hundred subjects have been evaluated in order to identify alpha 1-antitrypsin deficiency patients. According to their serum alpha 1-antitrypsin levels, they have been divided into three groups: 25 patients with severe deficiency (with both pathological alleles--ZZ, SZ or Z and rare deficiency allele--and, if clinically suggested, to be treated with augmentation therapy), 92 patients with intermediate deficiency (with one pathological allele, to be followed up in order to evaluate the risk to develop deficiency related disease) and 63 healthy subjects (normal alleles MM). They performed lung function test (including cardiopulmonary exercise test and methacholine bronchial challenge) chest X-ray and high resolution computed tomography, blood tests. Severe deficiency patients also performed perfusional lung scan to detect early disorders of blood flow, evaluation of arterial blood gases and liver echotomography. Expiratory flow limitation, the prevalence of vascular disease, the amount of urine elastin products and correlations between the amount of nitric oxide exhaled and bronchial hyperresponsiveness have been also investigated. The study showed that in Brescia county the deficiency is more common than expected and that evaluation of liver and vessels might be as useful as lung function tests. In addition, beneficial effect on local system has been observed. The longitudinal study might permit to detect early organ damage and to eliminate additive risk factors.

Adolescent↗