Dietary patterns and longitudinal change in hip bone mineral density among older men.

Studying dietary patterns is often more informative than individual nutrients or foods. We found that a Prudent dietary pattern (rich in vegetables and fish) was associated with reduced loss of total hip BMD in older men. A Prudent dietary pattern may be a potential lifestyle strategy for minimizing bone loss. INTRODUCTION: This study aimed to identify baseline dietary patterns using factor analysis in a cohort of older men and to evaluate whether the dietary patterns were associated with bone mineral density change (%ΔBMD) at the total hip and femoral neck over time. METHODS: Participants (n = 4379; mean age 72.9 ± 5.5 years) were from the Osteoporotic Fractures in Men (MrOS) prospective cohort study and had dietary data collected at baseline (March 2000-April 2002) and BMD measured at baseline and Visit 2 (March 2005-May 2006). Dietary intake was assessed with a brief Block food frequency questionnaire (FFQ); factor analysis was used to derive dietary patterns. BMD was measured by dual-energy x-ray absorptiometry (DXA); %ΔBMD was calculated from baseline to Visit 2. We used generalized linear regression to estimate least square (LS) means of %ΔBMD in quartiles of the dietary pattern scores adjusted for potential confounding factors. RESULTS: Two major dietary patterns were derived: Prudent (abundant in vegetables, salad, and non-fried fish) and Western (rich in hamburger, fries, processed meats, cheese, and sweets/desserts). There was an inverse association between adherence to the Prudent pattern and total hip %ΔBMD (p-trend = 0.028 after adjusting for age and clinical site; p-trend = 0.033 after further adjustment for smoking, calcium supplement use, diabetes, hypertension, and total energy intake). No other consistent associations between dietary patterns and %ΔBMD were observed. CONCLUSIONS: Greater adherence to a Prudent dietary pattern may attenuate total hip BMD loss (%ΔBMD) in older men.

Biological parameters of HIV-1 infection in primary intestinal lymphocytes and macrophages.

Mucosal surfaces are the portal of entry for most HIV-1 infections and play an important role in disease pathogenesis. To characterize the biological parameters of HIV-1 infection in mucosal cells, we used purified lamina propria lymphocytes and macrophages from normal human small intestine to determine the distribution of the HIV-1 receptor and coreceptors on intestinal mononuclear cells and the permissiveness of these cells to HIV-1 infection. Lamina propria lymphocytes expressed CD4, CCR5, and CXCR4. In contrast, lamina propria macrophages expressed CD4 but not CCR5 or CXCR4. Intestinal lymphocytes supported replication by R5 and X4 isolates of HIV-1, but lamina propria macrophages were permissive to neither. RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), and MIP-1beta inhibited infection of intestinal lymphocytes by BaL, indicating that R5 infection of the intestinal lymphocytes was mediated by CCR5. Thus, resident lamina propria lymphocytes, not macrophages, are the target mononuclear cell for HIV-1 infection in the intestinal mucosa during early HIV-1 infection.

Lamina propria lymphocytes, not macrophages, express CCR5 and CXCR4 and are the likely target cell for human immunodeficiency virus type 1 in the intestinal mucosa.

Most human immunodeficiency virus type 1 (HIV-1) infections are acquired via mucosal surfaces, and transmitted viruses are nearly always macrophage-tropic, suggesting that mucosal macrophages participate in early HIV-1 infection. Mucosal lymphocytes isolated from normal human intestine expressed CD4 (14,530+/-7970 antibody-binding sites [ABSs]/cell), CCR5 (2730+/-1524 ABSs/cell), and CXCR4 (2507+/-1840 ABSs/cell), but intestinal macrophages, which also expressed CD4 (2959+/-2695 ABSs/cell), displayed no detectable CCR5 or CXCR4 ABS. The absence of CCR5 on intestinal macrophages was not due to expression of the Delta32 deletion allele because matched-blood monocytes expressed CCR5. CCR5(+)CXCR4(+) intestinal lymphocytes supported both R5 (BaL) and X4 (IIIB) HIV-1 replication, whereas the CCR5(-)CXCR4(-) macrophages were not permissive to either isolate or other laboratory isolates (ADA and DJV) and primary isolates (MDR 24 and JOEL). In the intestinal mucosa, lymphocytes, not macrophages, are the likely target cell for R5 (and X4) HIV-1 and are the major source of HIV-1 production during early infection.

Retinyl substituted-benzyl ethers. Inhibition of mammary carcinogenesis by retinyl 3,4,5-trimethoxybenzyl ether (RTMBE).

Recently, we reported that retinyl 2-propynyl ether (RPE) inhibits MNU-induced mammary cancer in rats and is less toxic than RME and retinyl acetate. The preparation and biological investigations of retinyl ethers have now been extended to retinyl substituted-benzyl ethers, some of which bind to cellular retinol-binding protein. In long-term (160-180 days) experiments, retinyl 3,4,5-trimethoxybenzyl ether (RTMBE) has been shown to be active against MNU-induced mammary cancer in Sprague-Dawley rats. In effectiveness, RTMBE is comparable, at least, to retinyl acetate; but, unlike retinyl acetate, RTMBE is comparatively non-toxic to rats and mice, is not converted enzymatically to retinol, and does not cause significant increases in retinyl palmitate concentrations in the liver. RTMBE reaches high concentrations in mammary tissue. Two of the four RTMBE congeners that were evaluated in 90 day studies were moderately effective in inhibiting mammary carcinogenesis.

Murine toxicology and pharmacology of UAB-8, a conformationally constrained analog of retinoic acid.

(2E, 4E, 6E)-8-[3'-Ethyl-2'-(1-methylethyl)-2'-cyclohexen-1'-ylidene] -3, 7-dimethyl-2,4,6-octatrienoic acid (UAB-8) has potent activity in preventing papillomas on the skin of mice similar to that determined in a previous study for the homolog containing one less carbon atom. To evaluate the toxicological profile for UAB-8, relative to all-trans-retinoic acid (RA), female mice were dosed by oral gavage for 29 days with amounts of 0.05, 0.1, or 0.2 mmol/kg/day. For the two compounds, the effects on body weights were similar. Mice dosed with UAB-8, however, had a lower incidence of clinical signs of toxicity (alopecia, scaly skin, and limping). At necropsy, bone fractures, skin abnormalities, and splenomegaly were observed in some mice dosed with RA but not in any dosed with UAB-8. Lymph node hyperplasia was noted in some mice dosed with either dose of RA but only in those dosed with the highest dose of UAB-8. All dose levels of RA produced microscopic lesions in the bones of mice; only the highest dose of UAB-8 had this effect. RA and UAB-8 had similar effects on chondrogenesis in cultures of cells from mouse limb buds, an indication of comparable teratogenic effects. For mice dosed i.v. (10 mg/kg), there was a saturated phase of elimination of RA from plasma (Km = 0.61 microgram/ml and Vmax = 2572 micrograms/hr); no such phase was noted when UAB-8 was administered. UAB-8 had values for t1/2 alpha and t1/2 beta of 0.47 and 17.1 hr, respectively. Relative to RA, UAB-8 has a favorable toxicological profile and different pharmacokinetics.

A conformationally defined 6-s-trans-retinoic acid isomer: synthesis, chemopreventive activity, and toxicity.

A conformationally defined retinoic acid analog (1) which contains a dimethylene bridge to maintain the 6-s-trans orientation for two terminal double bonds in the polyene chain was synthesized. A Reformatsky reaction was utilized to extend the polyene chain of the starting enone, which provided exclusively the 9Z-configuration for the intermediate aldehyde. A Horners-Emmons condensation with this aldehyde then produced retinoic acid analogs with both 9Z- and 9Z,13Z-configurations. An I2-catalyzed isomerization of the intermediate 9Z-aldehyde yielded the all-E-aldehyde, which was olefinated as above to yield the (all-E)- and (13Z)-retinoic acid analogs of 1. Each configurational isomer of 1 was evaluated for its ability to inhibit the binding of retinoic acid to CRABP (chick skin) and to inhibit the chemical induction of ornithine decarboxylase in mouse skin. In each assay (all-E)-1 was the most active isomer, and this activity was comparable to or better than that for (all-E)-retinoic acid. (all-E)-1 and (13Z)-1 were both shown to be equally effective as (13Z)-retinoic acid in suppressing the proliferation of human sebaceous cells in vitro. (all-E)-1 was further evaluated for its ability to prevent the induction of mouse skin papillomas and to induce signs of vitamin A toxicity in mice. The cancer chemopreventive activity of (all-E)-1 was comparable to that of (all-E)-retinoic acid, and the toxicity was comparable to or slightly better than that of the natural vitamin.

Cancer chemopreventive 3-substituted-4-oxoretinoic acids.

The introduction of substituents at position 3 of methyl 4-oxoretinoate can be effected in good yields by alkylating the lithium dienolate. A second substituent can be introduced also, but the resulting 3,3-disubstituted-4-oxoretinoates were isolated in lower yields. Evidence was obtained for a slower rate of alkylation at the alpha-position (carbon 14) of the ester group. Some of these 4-oxoretinoic acid analogues showed high activity in assays in vivo for the inhibition of ornithine decarboxylase activity and carcinogen-induced papillomas in mouse skin.

Arachidonic acid turnover in peritoneal macrophages is altered in endotoxin-tolerant rats.

Peritoneal macrophages from endotoxin-tolerant rats have been found to exhibit depressed metabolism of arachidonic acid (AA) to prostaglandins and thromboxane in response to endotoxin. The effect of endotoxin tolerance on AA turnover in peritoneal macrophages was investigated by measuring [14C]AA incorporation and release from membrane phospholipids. Endotoxin tolerance did not affect the amount of [14C]AA incorporated into macrophages (30 min-24 h). However, the temporal incorporation of [14C]AA into individual phospholipid pools (15 min-24 h) was altered. In endotoxin-tolerant macrophages, [14C]AA incorporation into phosphatidylcholine (PC) (2, 4, 24 h) and phosphatidylethanolamine (PE) (8 h) was increased, while the incorporation into phosphatidylserine (PS) (2-24 h) was reduced (P less than 0.005) compared to control macrophages. There was no change in [14C]AA incorporation into phosphatidylinositol (PI). Following 2 or 24 h of incorporation of [14C]AA, macrophages were incubated (3 h) with endotoxin (50 micrograms/ml) or A23187 (1 microM), and [14C]AA release was measured. Endotoxin-tolerant macrophages released decreased (P less than 0.05) amounts of [14C]AA in response to both endotoxin and the calcium ionophore A23187 compared to controls. Control macrophages in response to endotoxin released [14C]AA from PC, PI and PE. In contrast, tolerant cells released [14C]AA only from PC (P less than 0.05). A23187 released [14C]AA from all four pools in the control cells, but only from PC and PE in the tolerant cells. These data demonstrate that endotoxin tolerance alters the uptake and release of AA from specific macrophage phospholipid pools. These results suggest that changes in AA turnover and/or storage are associated with endotoxin tolerance.

The effect of dietary supplementation with n-3 polyunsaturated fatty acids on the synthesis of interleukin-1 and tumor necrosis factor by mononuclear cells.

We examined whether the synthesis of interleukin-1 or tumor necrosis factor, two cytokines with potent inflammatory activities, is influenced by dietary supplementation with n-3 fatty acids. Nine healthy volunteers added 18 g of fish-oil concentrate per day to their normal Western diet for six weeks. We used a radioimmunoassay to measure interleukin-1 (IL-1 beta and IL-1 alpha) and tumor necrosis factor produced in vitro by stimulated peripheral-blood mononuclear cells. With endotoxin as a stimulus, the synthesis of IL-1 beta was suppressed from 7.4 +/- 0.9 ng per milliliter at base line to 4.2 +/- 0.5 ng per milliliter after six weeks of supplementation (43 percent decrease; P = 0.048). Ten weeks after the end of n-3 supplementation, we observed a further decrease to 2.9 +/- 0.5 ng per milliliter (61 percent decrease; P = 0.005). The production of IL-1 alpha and tumor necrosis factor responded in a similar manner. Twenty weeks after the end of supplementation, the production of IL-1 beta, IL-1 alpha, and tumor necrosis factor had returned to the presupplement level. The decreased production of interleukin-1 and tumor necrosis factor was accompanied by a decreased ratio of arachidonic acid to eicosapentaenoic acid in the membrane phospholipids of mononuclear cells. We conclude that the synthesis of IL-1 beta, IL-1 alpha, and tumor necrosis factor can be suppressed by dietary supplementation with long-chain n-3 fatty acids. The reported antiinflammatory effect of these n-3 fatty acids may be mediated in part by their inhibitory effect on the production of interleukin-1 and tumor necrosis factor.

Selective enhancement of thromboxane in macrophages and kidneys in cyclosporine-induced nephrotoxicity. Dietary protection by fish oil.

Cyclosporine (CsA) associated renal dysfunction is related in part to renal vasoconstriction. To identify the role of cyclooxygenase metabolites in the induction of vasoconstriction, we analyzed the effect of CsA on the synthesis of thromboxane (TxA2) prostacyclin (PGI2) and prostaglandin E2 (PGE2) in the kidney and peritoneal macrophages. Groups of rats were pair-fed diets enriched with 20% fish oil (FO) or corn oil (CO) for 4 weeks and then were injected with CsA 12.5 mg/kg/day i.p. for 2 weeks. CsA induced the synthesis of TxA2 and modestly reduced PGE2 and PGI2 in renal cortex and peritoneal macrophages. Feeding rats a diet enriched in FO containing omega-3 fatty acids as compared with CO without these fatty acids suppressed the increase in TxA2 and decreased the vasodilators PGE2 and PGI2 in the kidney and peritoneal macrophages, while modifying the decrease in the glomerular filtration rate and vacuolization in proximal convoluted tubules characteristic of rodent CsA-associated nephrotoxicity. Thus, CsA-initiated renal vasoconstriction is related to an increase in the vasoconstrictive Tx molecule and the reduction in vasodilator metabolites. Intrarenal macrophages represent a likely source of this Tx production. Feeding rats diets containing omega-3 fatty acids, known to be competitive inhibitors of cyclooxygenase metabolites, prevents CsA from selectively increasing TxA2 and preserves renal function.

Differential alteration of lipoxygenase and cyclooxygenase metabolism by rat peritoneal macrophages induced by endotoxin tolerance.

Altered macrophage arachidonic acid metabolism may play a role in endotoxic shock and the phenomenon of endotoxin tolerance induced by repeated injections of endotoxin. Studies were initiated to characterize both lipoxygenase and cyclooxygenase metabolite formation by endotoxin tolerant and non-tolerant macrophages in response to 4 different stimuli, i.e. endotoxin, glucan, zymosan, and the calcium ionophore A23187. In contrast to previous reports of decreased prostaglandin synthesis by tolerant macrophages, A23187-stimulated immunoreactive (i) leukotriene (LT)C4/D4 and prostaglandin (PG)E2 production by tolerant cells was greater than that by non-tolerant controls (p less than 0.001). However, A23187-stimulated i-6-keto-PGF1 alpha levels were lower in tolerant macrophages compared to controls. Stimulation of prostaglandin and thromboxane (Tx)B2 synthesis by endotoxin or glucan was significantly less in tolerant macrophages compared to controls (p less than 0.05). iLTC4/D4 production was not significantly stimulated by endotoxin or glucan, but was stimulated by zymosan in the non-tolerant cells. Synthesis of iLTB4 by control macrophages was stimulated by endotoxin (p less than 0.01). These results demonstrate that arachidonic acid metabolism via the lipoxygenase and cyclooxygenase pathways in macrophages is differentially altered by endotoxin tolerance.