Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0002736 (amyotrophic lateral sclerosis)
 19,048 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Liver cirrhosis is characterized by a severe impairment of the growth hormone/insulin-like growth factor-1 (GH-IGF-1) axis, that is, acquired GH resistance. The condition of the GH-IGF-1 axis in the phase of chronic liver disease (CLD) preceding cirrhosis, however, remains uncertain. The origin of GH resistance during CLD is multifactorial, and to date, the liver functional mass is considered to play a major role. Although proinflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and IL-1beta, were found to be elevated in patients with CLD and were shown to induce a state of GH resistance in other disease models, their involvement in the pathogenesis of GH resistance during CLD has never been investigated. We characterized the GH-IGF-1 axis by analyzing the individual components of the axis (GH, IGF-1, IGF-binding protein-3 [IGFBP-3], acid-labile subunit [ALS]) and the corresponding ratios (GH/IGF-1, GH/IGFBP-3, and GH/ALS) and verified the links with circulating proinflammatory cytokines (TNF-alpha, IL-1beta, and IL-6), in 34 patients with CLD and 12 healthy controls. Evolution of CLD from chronic hepatitis (CH, n = 17) to cirrhosis (CIR, n = 17) was associated with a progressive increase of GH resistance indices (e.g., GH/IGF-1 ratio: controls 0.5 +/- 0.9, CH 15.9 +/- 31.2, p < 0.01 vs. controls; CIR 188.4 +/- 282.7 mU/nmol, p < 0.001 vs. CH and controls), indicating its onset also in the early stages of CLD. The progressive increase in GH resistance indices matched the increase of circulatory TNF-alpha (e.g., TNF-alpha vs. GH/IGF-1, r = 0.54, p < 0.001). A similar trend was found for IL-6 without reaching statistical significance (r = 0.23, p = 0.13). We found undetectable levels of IL-1beta in our sample of patients and controls. We conclude that proinflammatory cytokines play an important role in the pathogenesis of GH resistance in CLD, but TNF-alpha is a major factor. In addition, GH resistance is present in CLD from the early stages. These results could begin new therapeutic lines of attack in the management of CLD.
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PMID:TNF-alpha and growth hormone resistance in patients with chronic liver disease. 1280 65

Growth hormone (GH) exercises its growth effects by stimulating insulin-like growth factor I (IGF-I) synthesis in the liver (endocrine IGF-I) and by inducing chondrocyte differentiation/replication and local production of IGF-I (paracrine/autocrine IGF-I). Injectable recombinant human (rh)IGF-I (mecasermin) has been available for nearly 20 years for treatment of the rare instances of GH insensitivity caused by GH receptor defects or GH-inhibiting antibodies. Full restoration of normal growth, as occurs with rhGH replacement of GH deficiency, is not seen, presumably because only the endocrine deficiency is addressed. RhIGF-I has also been effective as an insulin-sensitizing agent in severe insulin-resistant conditions. Although the insulin-sensitizing effect may benefit both type 1 and type 2 diabetes, there are no ongoing clinical trials because of concern about risk of retinopathy and other complications. Promotion of rhIGF-I for treatment of idiopathic short stature has been intensive, with neither data nor rationale suggesting that there might be a better response than has been documented with rhGH. Other applications that have either been considered or are undergoing clinical trial are based on the ubiquitous tissue-building properties of IGF-I and include chronic liver disease, cystic fibrosis, wound healing, AIDS muscle wasting, burns, osteoporosis, Crohn's disease, anorexia nervosa, Werner syndrome, X-linked severe combined immunodeficiency, Alzheimer's disease, muscular dystrophy, amyotrophic lateral sclerosis, hearing loss prevention, spinal cord injury, cardiovascular protection, and prevention of retinopathy of prematurity. The most frequent side effect is hypoglycemia, which is readily controlled by administration with meals. Other common adverse effects involve hyperplasia of lymphoid tissue, which may require tonsillectomy/adenoidectomy, accumulation of body fat, and coarsening of facies. The anti-apoptotic properties of IGF-I are implicated in cancer pathogenesis-a concern for long-term therapy. It is unlikely that mecasermin will be useful beyond the orphan indications of severe insulin resistance and GH insensitivity.
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PMID:Mecasermin (recombinant human insulin-like growth factor I). 1919 69