A sulphated glycosaminoglycan extract from Placopecten magellanicus inhibits the Alzheimer's disease β-site amyloid precursor protein cleaving enzyme 1 (BACE-1)

The clinically important anticoagulant heparin, a member of the glycosaminoglycan family of carbohydrates that is extracted predominantly from porcine and bovine tissue sources, has previously been shown to inhibit the β-site amyloid precursor protein cleaving enzyme 1 (BACE-1), a key drug target in Alzheimer's Disease. In addition, heparin has been shown to exert favourable bioactivities through a number of pathophysiological pathways involved in the disease processes of Alzheimer's Disease including inflammation, oxidative stress, tau phosphorylation and amyloid peptide generation. Despite the multi-target potential of heparin as a therapeutic option for Alzheimer's disease, the repurposing of this medically important biomolecule has to-date been precluded by its high anticoagulant potential. An alternative source to mammalian-derived glycosaminoglycans are those extracted from marine environments and these have been shown to display an expanded repertoire of sequence-space and heterogeneity compared to their mammalian counterparts. Furthermore, many marine-derived glycosaminoglycans appear to retain favourable bioactivities, whilst lacking the high anticoagulant potential of their mammalian counterparts. Here we describe a sulphated, marine-derived glycosaminoglycan extract from the Atlantic Sea Scallop, Placopecten magellanicus that displays high inhibitory potential against BACE-1 (IC₅₀ = 4.8 μg.mL^-1) combined with low anticoagulant activity; 25-fold less than that of heparin. This extract possesses a more favourable therapeutic profile compared to pharmaceutical heparin of mammalian provenance and is composed of a mixture of heparan sulphate (HS), with a high content of 6-sulphated N-acetyl glucosamine (64%), and chondroitin sulphate.

Glycosaminoglycans from Litopenaeus vannamei Inhibit the Alzheimer's Disease β Secretase, BACE1

Only palliative therapeutic options exist for the treatment of Alzheimer's Disease; no new successful drug candidates have been developed in over 15 years. The widely used clinical anticoagulant heparin has been reported to exert beneficial effects through multiple pathophysiological pathways involved in the aetiology of Alzheimer's Disease, for example, amyloid peptide production and clearance, tau phosphorylation, inflammation and oxidative stress. Despite the therapeutic potential of heparin as a multi-target drug for Alzheimer's disease, the repurposing of pharmaceutical heparin is proscribed owing to the potent anticoagulant activity of this drug. Here, a heterogenous non-anticoagulant glycosaminoglycan extract, obtained from the shrimp Litopenaeus vannamei, was found to inhibit the key neuronal β-secretase, BACE1, displaying a more favorable therapeutic ratio compared to pharmaceutical heparin when anticoagulant activity is considered.

Inhibition of BACE1, the β-secretase implicated in Alzheimer's disease, by a chondroitin sulfate extract from Sardina pilchardus

The pharmaceutical and anticoagulant agent heparin, a member of the glycosaminoglycan family of carbohydrates, has previously been identified as a potent inhibitor of a key Alzheimer's disease drug target, the primary neuronal β-secretase, β-site amyloid precursor protein cleaving enzyme 1 (BACE1). The anticoagulant activity of heparin has, however, precluded the repurposing of this widely used pharmaceutical as an Alzheimer's disease therapeutic. Here, a glycosaminoglycan extract, composed predominantly of 4-sulfated chondroitin sulfate, has been isolated from Sardina pilchardus, which possess the ability to inhibit BACE1 (IC50 [half maximal inhibitory concentration] = 4.8 μg/mL), while displaying highly attenuated anticoagulant activities (activated partial thromboplastin time EC50 [median effective concentration] = 403.8 μg/mL, prothrombin time EC50 = 1.3 mg/mL). The marine-derived, chondroitin sulfate extract destabilizes BACE1, determined via differential scanning fluorimetry (ΔTm -5°C), to a similar extent as heparin, suggesting that BACE1 inhibition by glycosaminoglycans may occur through a common mode of action, which may assist in the screening of glycan-based BACE1 inhibitors for Alzheimer's disease.

A semi-synthetic glycosaminoglycan analogue inhibits and reverses Plasmodium falciparum cytoadherence

A feature of mature Plasmodium falciparum parasitized red blood cells is their ability to bind surface molecules of the microvascular endothelium via the parasite-derived surface protein Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1). This ligand is associated with the cytoadherence pathology observed in severe malaria. As pRBC treated with effective anti-malarial drugs are still able to cytoadhere, there is therefore a need to find an adjunct treatment that can inhibit and reverse the adhesion process. One semi-synthetic, sulfated polysaccharide has been identified that is capable of inhibiting and reversing sequestration of pRBC on endothelial cells in vitro under physiological flow conditions. Furthermore, it exhibits low toxicity in the intrinsic (APTT assay) and extrinsic (PT assay) clotting pathways, as well as exhibiting minimal effects on cell (HUVEC) viability (MTT proliferation assay). These findings suggest that carbohydrate-based anti-adhesive candidates may provide potential leads for therapeutics for severe malaria.

2-Aryl indole NK1 receptor antagonists: optimisation of indole substitution

The synthesis and biological evaluation of a series of 2-aryl indoles with high affinity for the human neurokinin-1 (hNK1) receptor are reported, concentrating on optimisation of the indole substitution.

Evaluation of the effectiveness of a community-based enriched model prenatal intervention project in the District of Columbia

OBJECTIVE

To evaluate an enriched prenatal intervention program designed to reduce the risk of low birth weight.

STUDY SETTING

Freestanding community-based prenatal intervention project located in a poor inner-city community, serving mostly African American women.

STUDY DESIGN

All women less than 29 weeks pregnant were eligible to participate. They were compared to women who lived in neighborhoods with similar rates of poverty.

DATA COLLECTION

The birth certificate was the source of data on maternal age, education, marital status, timing and frequency of prenatal care attendance, parity, gravidity, prior pregnancy terminations, fetal and child deaths, and birth weight.

PRINCIPAL FINDINGS

Thirty-eight percent of the women who delivered live-born infants in the study area participated in the program. There were no differences in low- and very low birthweight rates in the study and comparison groups. In a secondary analysis comparing participants and nonparticipants in the study census tracts, participants were at higher risk for low and very low birth weight, and they adhered more closely to the schedule of prenatal visits than nonparticipants. Low- and very low birthweight rates were lower among participants than among nonparticipants and comparison women.

CONCLUSION

The Better Babies Project did not have an effect on the overall low- and very low birthweight rates in the study census tracts. This was probably due to the low participation rates and the high population mobility.

Longitudinal assessment of early onset periodontitis

The purpose of this study was to determine the clinical course of early onset periodontitis and to investigate factors which may influence its clinical course. For the past 15 years we have been conducting a study of families with early onset periodontitis, and have examined 142 localized juvenile periodontitis and 185 severe generalized early onset periodontitis patients. In order to study the clinical course of early onset periodontitis we recalled our subject population to determine their periodontal status. Forty (40) patients with localized early onset periodontitis (LJP) and 48 with generalized early onset periodontitis (SP) were re-examined. The time since the most recent visit for LJP patients was approximately 3 years and for SP patients almost 4 years. LJP patients who received periodontal therapy on the average gained periodontal attachment. In contrast, LJP patients who did not receive therapy lost periodontal attachment. SP patients lost periodontal attachment regardless of whether or not they had periodontal therapy. SP patients also lost an average of one tooth during the approximately 4 years of observation. LJP patients lost very few teeth with only 4 teeth being lost in 40 patients. The results of this study suggest that localized juvenile periodontitis is a stable disease in most individuals. In contrast, patients with severe generalized early onset periodontitis continued to lose both periodontal attachment and teeth.

Amino acid- and amine-induced gastrin release from isolated rat endocrine granules

Secretory granules from rat antral tissue were isolated by differential centrifugation in sucrose and were confirmed as intact by electron microscopy. Gastrin release from the isolated granules was measured in response to stimulation with amino acids or their decarboxylated amine metabolites. Nine of 13 amino acids tested were ineffective at inducing gastrin release, whereas all 13 of the amine metabolites were potent stimulants of gastrin release. A pH gradient across the granule fraction membranes was estimated by acridine orange fluorescence and indicated an acidic interior. Changes in acridine orange fluorescence as an indicator of pH gradient dissipation showed that all of the amines, but only one of the amino acids, reversed acridine orange fluorescence. Ammonium chloride, similar to amines, both reversed acridine orange fluorescence and induced release of gastrin. It is concluded that amines 1) may directly stimulate gastrin granules to release their contents and 2) tend to alkalinize the gastrin granule interior. Some amino acids, in contrast, appear to directly stimulate gastrin release and do not affect the granule pH gradient.

Effects of milk, prostaglandin, and antacid on experimentally induced duodenitis in the rat. Use of myeloperoxidase as an index of inflammation

Ulcerogenesis of the duodenal mucosa frequently involves an inflammatory reaction with infiltration of leukocytes. Measurement of neutrophil myeloperoxidase activity might thus be a sensitive indicator of damage, before visible lesions occur. To test this possibility, a rat model for duodenal injury was used where fasted animals were treated with indomethacin and histamine-diHCl. Twenty-four hours after indomethacin treatment, duodenal tissues were collected for histochemical staining and biochemical assay for myeloperoxidase activity. Indomethacin- and histamine-challenged rats had significantly elevated myeloperoxidase activity compared to unchallenged controls (P less than 0.05) for both histochemistry and biochemistry. There was also a significant correlation between these two parameters (r = 0.68, P less than 0.001). The duodenal injury model then was used to test the effectiveness of known gastric protective agents. Results indicated that milk and buttermilk did not aggravate or protect against duodenal injury, while antacid and prostaglandin did significantly protect against inflammation (P less than 0.02). We concluded that measurement of myeloperoxidase activity is a sensitive and potentially useful estimate of duodenal injury that can be valuable in assessing ulcerogenesis and healing.

Intestinal accumulation of lead salts and milk lead by suckling rats

Absorption of lead is known to be enhanced during infancy. In this study, the sites of intestinal accumulation of Pb by suckling rats have been determined under various conditions using 203Pb as a tracer. When 203Pb was administered intragastrically (IG) as a soluble salt, accumulation occurred primarily in the duodenum, regardless of dose and vehicle. In contrast, when rat pups suckled from a dam which had received 203Pb, the only region of the small intestine showing accumulation of radioactivity was the ileum. To confirm that these differences were not related to the route of administration, rat milk was labeled with 203Pb and was then used for IG administration. Once again, accumulation (4 hr post-administration) was confined to the ileum. When the dose was increased 10-fold, milk Pb displayed some accumulation in duodenal tissue, but very much less than that of soluble Pb at the same time and dosage. At 20 hr postadministration, there was negligible 203Pb in any region of the small intestine following administration as a soluble salt, but substantial retention in ileal tissue following administration in milk. The strikingly different patterns of intestinal accumulation obtained with Pb salts as compared with milk Pb suggest different modes of absorption of Pb ingested in these two forms.

Symptomatic papillary tumour of the pulmonary valve

Papillary ‘tumours’ are small pedunculated lesions of the valve cusps and result from wear-and-tear. They are therefore frequent post-mortem findings in older patients. The vast majority are clinically silent, though occasionally such lesions when on the aortic valve may produce symptoms of myocardial or cerebral ischaemia. None has been known to cause symptoms when in the right side of the heart.

A 52-year-old woman is reported who had transient episodes of right ventricular outflow obstruction related to the presence of a papillary tumour on the pulmonary valve. Extensive radiotherapy to the chest wall was thought to be a causal factor.