Detection, evaluation, and treatment of high blood cholesterol in adults (Adult Treatment Panel III)

In 1901 a physician, Archibald Garrod, observed a patient with black urine. He used this simple observation to demonstrate that a single mutant gene can produce a discrete block in a biochemical pathway, which he called an “inborn error of metabolism”. Garrod’s brilliant insight anticipated by 40 years the one gene-one enzyme concept of Beadle and Tatum. In similar fashion the chemist Linus Pauling and the biochemist Vernon Ingram, through study of patients with sickle cell anemia, showed that mutant genes alter the amino acid sequences of proteins. Clearly, many fundamental advances in biology were spawned by perceptive studies of human genetic diseases (1). We began our work in 1972 in an attempt to understand a human genetic disease, familial hypercholesterolemia or FH. In these patients the concentration of cholesterol in blood is elevated many fold above normal and heart attacks occur early in life. We postulated that this dominantly inherited disease results from a failure of end-product repression of cholesterol synthesis. The possibility fascinated us because genetic defects in feedback regulation had not been observed previously in humans or animals, and we hoped that study of this disease might throw light on fundamental regulatory mechanisms. Our approach was to apply the techniques of cell culture to unravel the postulated regulatory defect in FH. These studies led to the discovery of a cell surface receptor for a plasma cholesterol transport protein called low density lipoprotein (LDL) and to the elucidation of the mechanism by which this receptor mediates feedback control of cholesterol synthesis (2,3). FH was shown to be caused by inherited defects in the gene encoding the LDL receptor, which disrupt the normal control of cholesterol metabolism. Study of the LDL receptor in turn led to the understanding of receptor-mediated endocytosis, a genera! process by which cells communicate with each other through internalization of regulatory and nutritional molecules (4). Receptor-mediated endocytosis differs from previously described biochemical pathways because it depends upon the continuous and highly controlled movement of membraneembedded proteins from one cell organelle to another in a process termed

https://science.sciencemag.org/content/sci/232/4746/34.full.pdf

A receptor-mediated pathway for cholesterol homeostasis.

Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.

The Effects of Plant Flavonoids on Mammalian Cells:Implications for Inflammation, Heart Disease, and Cancer

A B S T R AC T BACKGROUND The order and magnitude of pathologic processes in Alzheimer’s disease are not well understood, partly because the disease develops over many years. Autosomal dominant Alzheimer’s disease has a predictable age at onset and provides an opportunity to determine the sequence and magnitude of pathologic changes that culminate in symptomatic disease. METHODS In this prospective, longitudinal study, we analyzed data from 128 participants who underwent baseline clinical and cognitive assessments, brain imaging, and cerebrospinal fluid (CSF) and blood tests. We used the participant’s age at baseline assessment and the parent’s age at the onset of symptoms of Alzheimer’s disease to calculate the estimated years from expected symptom onset (age of the participant minus parent’s age at symptom onset). We conducted cross-sectional analyses of baseline data in relation to estimated years from expected symptom onset in order to determine the relative order and magnitude of pathophysiological changes. RESULTS Concentrations of amyloid-beta (Aβ)42 in the CSF appeared to decline 25 years before expected symptom onset. Aβ deposition, as measured by positron-emission tomography with the use of Pittsburgh compound B, was detected 15 years before expected symptom onset. Increased concentrations of tau protein in the CSF and an increase in brain atrophy were detected 15 years before expected symptom onset. Cerebral hypometabolism and impaired episodic memory were observed 10 years before expected symptom onset. Global cognitive impairment, as measured by the Mini–Mental State Examination and the Clinical Dementia Rating scale, was detected 5 years before expected symptom onset, and patients met diagnostic criteria for dementia at an average of 3 years after expected symptom onset. CONCLUSIONS We found that autosomal dominant Alzheimer’s disease was associated with a series of pathophysiological changes over decades in CSF biochemical markers of Alzheimer’s disease, brain amyloid deposition, and brain metabolism as well as progressive cognitive impairment. Our results require confirmation with the use of longitudinal data and may not apply to patients with sporadic Alzheimer’s disease. (Funded by the National Institute on Aging and others; DIAN ClinicalTrials.gov number, NCT00869817.)

/pdf/clinical-and-biomarker-changes-in-dominantly-inherited-66jpsco78g.pdf

Clinical and Biomarker Changes in Dominantly Inherited Alzheimer’s Disease

Natural killer T (NKT) lymphocytes express an invariant T cell antigen receptor (TCR) encoded by the Valpha14 and Jalpha281 gene segments. A glycosylceramide-containing alpha-anomeric sugar with a longer fatty acyl chain (C26) and sphingosine base (C18) was identified as a ligand for this TCR. Glycosylceramide-mediated proliferative responses of Valpha14 NKT cells were abrogated by treatment with chloroquine-concanamycin A or by monoclonal antibodies against CD1d/Vbeta8, CD40/CD40L, or B7/CTLA-4/CD28, but not by interference with the function of a transporter-associated protein. Thus, this lymphocyte shares distinct recognition systems with either T or NK cells.

http://science.sciencemag.org/content/sci/278/5343/1626.full.pdf

CD1d-restricted and TCR-mediated activation of valpha14 NKT cells by glycosylceramides.

Hypolipidemic effects in dogs of ML-236B, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme a reductase

There is considerable interest in the discovery of hypocholesterolemic drugs whose mode of action is the inhibition of sterol biosynthesis. Culture broths of microorganisms have yielded active compounds that specifically inhibit 3hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase, the rate-limiting enzyme in cholesterol biosynthesis. The first of these to be described was ML-236B (compactin)1). Its isolation from Penicillium citrinum and hypocholesterolemic properties were extensively studied by ENDO and his associates2.3). The clinical efficacy of ML-236B in lowering plasma cholesterol has also been reported2~5). Later, a more potent relative of ML-236B, designated monacolin K (mevinolin), was isolated by ENDO and ALBERTS et a!. from Monascus ruber6,7) and Aspergillus terreus8). Along with these two compounds, several metabolites related to either ML-236B or monacolin K were isolated1,9,10). The present communication describes the isolation, structure and some of the biological properties of two new compounds designated monacolins J and L (Fig. 1). Monascus ruber No. 1005 was grown aerobically in a medium containing glucose 6%, peptone 2.5 %, corn steep liquor (Corn Products Co., U.S.A.) 0.5 %, ammonium chloride 0.5 % at 25°C for 10 days. The culture filtrate (5 liters) was adjusted to pH 3 with HCl and extracted with ethyl acetate (5 liters). The solvent layer was dried over Na2SO4, filtered, and then evaporated to dryness in vacuo. A benzene solution of the oily residue was, after filtration, washed twice with 5 % NaHCO3 (100m]) and then mixed with 100 m] of 0.2 M NaOH. The mixture was stirred at room temperature for 2 hours to hydrolyze the S-lactone ring. The aqueous layer was adjusted to pH 3 with HCI and then extracted twice with ethyl acetate (100 ml). The solvent layers were dried over Na2SO4 and then evaporated to dryness. The resulting oily residue (260 mg) was dissolved in a small volume of benzene; crystals formed were removed by filtration, and purified by chromatography in a silica gel (Wako gel C-200) column (10 g). The column was developed first with 50 ml of dichloromethane, then with 600 ml of dichloromethane ethyl acetate (9: 1) followed by 900 ml of dichloromethane ethyl acetate (8: 2) to elute monacolins L, K and J, respectively. The dichloromethane fraction was evaporated to dryness and applied to a silica gel column (Wako gel C-200, 5 g). The column was washed with 30 ml of n-hexane, then developed with 500 ml of n-hexane acetone (9: 1) to elute monacolin L. The active fraction was evaporated to dryness and dissolved in 10 ml of benzene. The solution was washed twice with 5 ml of 5 % NaHCO3, dried over Na2SO4 and evaporated to dryness, yielding 24 mg (white powder) of monacolin L. The dichlorornethane ethyl acete (8: 2) fraction obtained above was evaporated to dryness, dissolved in 10 m] of benzene and washed twice with 5 ml of 5 % NaHCO3. The benzene soluFig. 1.

/pdf/monacolins-j-and-l-new-inhibitors-of-cholesterol-210gqtiy43.pdf

Monacolins J and L, new inhibitors of cholesterol biosynthesis produced by Monascus ruber.

In the early 1970s we isolated the first statin, mevastatin (formerly called compactin or ML-236B), from Penicillium citrinum , as a potent inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the rate-controlling enzyme in cholesterol synthetic pathway. By the end of the 1970s we had demonstrated that mevastatin was highly effective in lowering serum total and low-density lipoprotein (LDL) cholesterol in both experimental animals and patients with primary hypercholesterolemia. The discovery of mevastatin paved the way for the worldwide development of its analogues (statins), and since then several statins—lovastatin, simvastatin, pravastatin, fluvastatin and atorvastatin—have been approved in many countries and are currently used by millions of patients.

The origin of the statins

A compound active against sterol biosynthesis was isolated from the culture filtrate of the fungus Prthium ultimum IAM 6073 and identified as citrinin which had been isolated as an antibiotic.') The sequence of reactions by which cholesterol is formed from acetyl-CoA is one of the most complex biosynthetic pathways in eukaryotic cells. In every vertebrate species so far studied, potent activity in cholesterol synthesis can be detected in the liver which seems to be the sole organ supplying plasma cholesterol. Because of the importance of the plasma cholesterol level in atherosclerosis, several approaches have been made to control it by decreasing cholesterol synthesis in the liver.2~4) The inhibition of endogenous cholesterol synthesis could lead to a lowering of its level in the plasma. This communication describes inhibition by citrinin of cholesterol and ergosterol synthesis and its hypocholesterolemic activity in rats. The enzymatic synthesis of cholesterol was assayed by measuring the radioactive nonsaponifiable products derived from 14C-acetate in a rat liver enzyme system by the method of KNAUSS et al.5) Culture filtrates of microorganisms including fungi, bacteria, and actinomycetes were tested for inhibitory activity in this assay system, and Pvthium ultimum was selected as one of the producers of an inhibitor. The fungus was cultured aerobically in a medium containing 2.0% glucose, 2% peptone and 0.3 % corn steep liquor in a 30-liter fermentor for 4 days. The culture filtrate was adjusted to pH 2, and the active compound was extracted with benzene. The extract was concentrated in vacuo, resulting in the formation of yellowish crystals of the active compound. The compound was recrystallized from hot chloroform. Calcd.: C 62.39, H 5.64, O 31.97 Found: C 62.39, H 5.58, O 32.03 The chemical structure of 4,6-dihydro-8-hydroxy-3,4, 5-trimethyl 6 oxo3 H-2-benzopyran-7 carboxylic acid was suggested by n.m.r. spectrum. The identity with citrinin was proven by comparison with authentic samples (kindly supplied by Dr. S. UDAGAWA, National Institute of Hygienic Science, Tokyo). As shown in Fig. 1, citrinin strongly inhibited cholesterol synthesis from 14C-acetate. The concentration at which cholesterol synthesis was inhibited by 50 % was about 8.5 mcg/ml (3.4 x 10-5M). Under the same conditions, 14C-acetate incorporation into fatty acid fraction was also reduced by citrinin but to a lesser extent. The concentration of the inhibitor required for 50 inhibition of fatty acid synthesis was approximately 50 mcg/ml. Citrinin was also inhibitory in the sterol synthesizing system of the yeast Saccharomyces cerevisiae in which 14C-acetate incorporation into nonsaponifiable lipids was determined as described by KAWAGUCHI (Fig. 1).e) At a concentration of 100 mcg/ml, the inhibitor reduced the sterol synthesis by approximately 50%. For studies of hypocholesterolemic effect of

https://www.jstage.jst.go.jp/article/antibiotics1968/29/8/29_8_841/_pdf

Citrinin, an inhibitor of cholesterol synthesis.

Four new analogues of concanamycin family, designated concanamycins D, E, F G, were isolated from the mycelium of Streptomyces sp. A1509 by solvent extraction, silica gel column chromatography and HPLC. Structures of these compounds were identified by the combination of spectroscopic analyses. All of these compounds were structurally related to concanamycins A, B and C, which had been isolated previously, and inhibited the acidification of rat liver lysosomes at 10(-11)-10(-9) M concentration. The structure-activity study showed that the 18-membered macrolide ring and the 6-membered hemiketal ring portions of the molecules of concanamycin family are responsible for potent inhibitory activity.

Akira Endo

Papers

Hypolipidemic effects in dogs of ML-236B, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme a reductase

Monacolins J and L, new inhibitors of cholesterol biosynthesis produced by Monascus ruber.

The origin of the statins

Citrinin, an inhibitor of cholesterol synthesis.

Isolation, characterization and biological activities of concanamycins as inhibitors of lysosomal acidification.