Apolipoprotein E polymorphism has no independent effect on plasma levels of lipoprotein(a)

Previous studies show conflicting results concerning an influence of apolipoprotein E (apo E) phenotype on lipoprotein(a) (Lp(a)) plasma levels. We speculated that it is not the apo E phenotype itself but rather its effect on plasma lipid concentrations that might influence Lp(a) levels. In 1562 subjects concentrations of triglycerides, LDL-cholesterol and Lp(a) were measured by standard laboratory methods. Apo(a) and apo E isoforms were determined by sodium dodecyl sulfate gel electrophoresis and isoelectric focusing, respectively, followed by immunoblotting. An univariate analysis revealed a significant influence of apo(a) isoforms, apo E phenotype, triglycerides and LDL-cholesterol on Lp(a) plasma levels (ANOVA: P < 0.001, P < 0.02, P < 0.001 and P < 0.001, respectively). In a multivariate analysis, however, the influence of the apo E phenotype was no longer significant (P>0.10), whereas apo(a) isoforms, LDL-cholesterol quintiles and triglyceride quintiles explained 29.2, 2.8 and 1.0% of the variation of the Lp(a) levels (for all three variables: P < 0.001). We conclude that apo E polymorphism does not exert an independent effect on Lp(a) concentrations. Any influence is mediated through the effect of apo E polymorphism on plasma lipids.

A duplication of 12 bp in the critical cysteine rich domain of the RET proto-oncogene results in a distinct phenotype of multiple endocrine neoplasia type 2A

Activating germline mutations in the cysteine-rich domain of the RET proto-oncogene are found in >92% of the cases of multiple endocrine neoplasia type 2A (MEN2A) and 85% of familial medullary thyroid carcinoma (FMTC). In virtually 100% of patients with identified mutations one of five cysteines is altered by a missense mutation. In a MEN2A family with 14 affected and 11 unaffected living members, hypercalcemia was diagnosed in eight patients and histological evaluation revealed parathyroid hyperplasia in all cases examined (10/10). No member of this family showed any evidence for the existence of pheochromocytoma. This is the first documentation of a family without pheochromocytoma but with a high incidence of parathyroid disease. Genetic analysis revealed the presence of an unusual heterozygous mutation in exon 11 of the RET proto-oncogene representing a duplication of 12 bp resulting in the insertion of four amino acids between codon 634 (Cys) and 635 (Arg), thus creating an additional cysteine residue.

Low lipoprotein (a) levels during acute viral hepatitis

High serum concentrations of lipoprotein (a) [Lp(a)] are considered a risk factor for premature atherosclerosis. Besides apolipoprotein B-100, Lp(a) consists of apolipoprotein (a) [apo(a)], which shows a remarkable size polymorphism. The serum concentration of Lp(a) is considerably influenced by this apo(a) phenotype. Because Lp(a) is synthesized in the liver, we wondered whether and to what extent Lp(a) levels might be affected by acute liver disease. We compared Lp(a) serum concentrations in 74 patients (54% male, 46% female; mean age, 46 years) with acute viral hepatitis (32, 28, and 14 with hepatitis A, B, and C, respectively) with those in 404 healthy controls (57% men, 43% women; mean age, 47 years). In addition, the intraindividual course of Lp(a) concentration during and after acute hepatitis was followed in a subgroup of 23 patients (15, 6, and 2 with hepatitis A, B, and C, respectively). During acute hepatitis, median Lp(a) concentrations in the patient group were significantly diminished compared with controls (7 vs. 17 mg/dL;P < .0001, Mann-Whitney test). Any bias by an unequal isoform distribution was excluded because there was no significant difference in the isoform distribution between patients and controls (P > .10, chi2 test). Furthermore, the decrease in Lp(a) concentration during acute hepatitis was independent of the molecular weight of the apo(a) isoform. Longitudinally observed patients showed a marked increase in Lp(a) concentration during convalescence (7 to 32 mg/dL;P < .0001, Wilcoxon test). Our results show that acute hepatitis is associated with decreased Lp(a) serum levels. Further studies are needed to evaluate whether Lp(a) serum concentration might be clinically useful as a parameter of liver function.

Effects of n-3 fatty acids and fenofibrate on lipid and hemorrheological parameters in familial dysbetalipoproteinemia and familial hypertriglyceridemia

There is increasing evidence that hemorrheological abnormalities are associated with an enhanced risk of atherosclerosis. The n-3 fatty acids (n-3-FA) have been shown to have beneficial effects on atherosclerosis in patients with dyslipoproteinemias. We studied 23 patients with elevated plasma triglycerides to evaluate the influence of fish oil and fenofibrate therapy on hemorrheological parameters (15 patients with familial hypertriglyceridemia [FHTG] and eight with familial dysbetalipoproteinemia [FDL]). The patients (one woman and 22 men aged 45.7 +/- 2.0 years) were treated with increasing doses of n-3-FA (1.8 to 3.6 g/d: 0.9 to 1.8 g eicosapentaenoic acid and 0.6 to 1.2 g docosahexaenoic acid) for 8 weeks. Lipid parameters, whole-blood viscosity at different shear rates, plasma viscosity, fibrinogen concentration, and red blood cell aggregation (RCA) were measured at baseline and at weeks 2, 4, 8 (end of n-3-FA therapy), and 12. Compliance was ensured by measuring plasma concentrations of eicosapentaenoic acid and docosahexaenoic acid. After 12 weeks, patients began treatment with fenofibrate (250 mg daily); investigations were performed again at week 20. Total triglycerides (from 6.90 +/- 1.70 to 3.61 +/- 0.78 mmol/L in FDL and 7.44 +/- 1.50 to 4.15 +/- 0.55 in FHTG), very-low-density lipoprotein (VLDL) triglycerides, and VLDL cholesterol were significantly decreased with n-3-FA therapy in both groups (P < .05). In FHTG, low-density lipoprotein (LDL) cholesterol increased significantly (from 2.75 +/- 0.28 to 3.97 +/- 0.35 mmol/L, P < .01); in FDL, total cholesterol decreased (from 9.76 +/- 1.32 to 7.34 +/- 1.07 mmol/L, P < .05). No significant changes were observed in hemorrheological parameters, except for reduced RCA with 3.6 g n-3-FA in FHTG. However, with fenofibrate therapy, in addition to comparable lipoprotein changes seen with fish oil, fibrinogen levels and plasma and blood viscosity decreased in patients with FDL. We conclude that n-3-FA and fenofibrate have comparable effects on lipid parameters in patients with FDL and FHTG. Because of additional beneficial effects on hemorrheological parameters, fenofibrate may be preferred for the treatment of FDL.

Mutations of the ret protooncogene in German multiple endocrine neoplasia families: relation between genotype and phenotype. German Medullary Thyroid Carcinoma Study Group

It has been suggested that not only the position but also the nature of the mutations of the ret protooncogene strongly correlate with the clinical manifestation of the multiple endocrine neoplasm type 2 (MEN 2) syndrome. In particular, individuals with a Cys634-Arg substitution should have a greater risk of developing parathyroid disease. We, therefore, analyzed 94 unrelated families from Germany with inherited medullary thyroid carcinoma (MTC) for mutation of the ret protooncogene. In all but 1 of 59 families with MEN 2A, germline mutations in the extracellular domain of the ret protein were found. Some 81% of the MEN 2A mutations affected codon 634. Phenotype-genotype correlations suggested that the prevalence of pheochromocytoma and hyperparathyroidism is significantly higher in families with codon 634 mutations, but there was no correlation with the nature of the mutation. In all but 1 of 27 familial MTC (FMTC) families, mutations were detected in 1 of 4 cysteines in the extracellular domain of the ret protooncogene. Half of the FMTC mutations affected codon 634. Mutations outside of codon 634 occurred more often in FMTC families than in MEN 2A families. In all but 1 of 8 MEN 2B patients, de novo mutations in codon 918 were found. These data confirm the preferential localization of MEN 2-associated mutations and the correlation between disease phenotype and the position of the ret mutation, but there was no correlation between the occurrence of hyperparathyroidism or pheochromocytoma and the nature of the mutation.

Isolated familial pheochromocytoma as a variant of von Hippel-Lindau disease

Inherited pheochromocytomas are often part of familial syndromes, especially multiple endocrine neoplasia type 2 (MEN 2), retinal cerebellar hemangioblastomatosis [von Hippel-Lindau (vHL) disease] or neurofibromatosis type 1. It is not clear whether isolated familial pheochromocytoma exists as a separate clinical entity. In a family with pheochromocytomas in three generations and with at least seven affected members, we investigated by clinical and genetic analyses the presence or absence of associated conditions. The clinical investigations included ophthalmological and radiological studies for von Hippel-Lindau disease (magnetic resonance imaging of the brain, computed tomography of the abdomen, and direct ophthalmoscopy after mydriasis) and annual calcitonin stimulation tests for C cell disease in five members who agreed to regular follow-up. Besides the pheochromocytomas (so far, these have been multiple in five of seven individuals) no definite second associated condition was found. Genetic analysis did not identify any MEN 2-specific RET protooncogene point mutations (which are present in 97% of MEN 2a families). However, despite the complete absence of other clinical manifestations of the vHL disease (besides pheochromocytomas), a previously undescribed germline missense mutation in the vHL tumor suppressor gene was found (C775G transversion with a predicted substitution of a leucine by a valine at codon 259 in the putative vHL protein). We conclude that in this family the sole occurrence of pheochromocytoma is a variant of vHL disease.

[Effects of a vegetarian life style on health]

A vegetarian diet has a positive effect on various risk factors for coronary artery disease: these include usually lower average body weight, lower total and LDL cholesterol levels, and lower blood pressure. In conjunction with a generally more healthy way of life (more exercise, less alcohol and tobacco use), vegetarians have roughly 30% reduction in overall mortality. The prevalence of bronchial, colon and breast cancer is also lower. In particular in its strict form (total vegetarianism or veganism), a vegetarian regimen may lead to deficiency disorders, in particular vitamin B12 deficiency, which may occur especially in vegetarian children, pregnant or lactating women. Overall, however, a vegetarian regimen has a more beneficial effect on health than the usual Central European diet.

Lipoprotein(a) concentrations and phenotypes in controls and patients with hypercholesterolemia or hypertriglyceridemia

Lipoprotein(a) [Lp(a)] concentrations are known to be stable under various dietary and drug regimens. Little is known about the influence of hyperlipoproteinemia on Lp(a) levels. Therefore, we investigated Lp(a) concentrations and apolipoprotein(a) [apo(a)] polymorphism in 147 patients with hypertriglyceridemia and in 93 patients with hypercholesterolemia and compared them with 404 subjects without hyperlipoproteinemia (controls). Despite a similar apo(a) isoform and phenotype distribution, Lp(a) concentrations differed significantly (P < .0001) between the three groups. The median Lp(a) level in control subjects was 17 mg/dL (mean, 38 mg/dL), compared with 38 mg/dL (mean, 56 mg/dL) in patients with hypercholesterolemia and 9 mg/dL (mean, 21 mg/dL) in those with hypertriglyceridemia. These differences persisted after exclusion of 61 subjects with coronary heart disease. The inverse correlation between the molecular weight of the apo(a) isoforms and the Lp(a) concentration was preserved within each group (P < .001), but for every molecular weight range studied the level of Lp(a) was always higher in patients with hypercholesterolemia and always lower in those with hypertriglyceridemia than in controls. We conclude that hypertriglyceridemia or hypercholesterolemia have profound--but divergent--influences on the concentration of Lp(a).

Healing of protein losing hypertrophic gastropathy by eradication of Helicobacter pylori--is Helicobacter pylori a pathogenic factor in Ménétrier's disease?

Hypertrophic gastropathy--that is, Ménétrier's disease--was found, in a retrospective analysis, to be associated with Helicobacter pylori in more than 90% of patients. It is proposed that hypertrophic gastropathy represents a special form of H pylori gastritis in these patients. A case is described of a 28 year old woman with Ménétrier's disease associated with proved protein loss from the stomach. Treatment with cimetidine for more than three years had little benefit when colonisation by H pylori was detected. Density of H pylori colonisation and activity of gastritis, which was also present in the first biopsy specimens taken five years ago, were more pronounced in the body than in the antrum, which is in agreement with the characteristics of H pylori gastritis found in other cases with Ménétrier's disease. A 14 day antibacterial treatment course with 750 mg amoxicillin three times a day combined with 40 mg omeprazole three times a day was started in April 1991. This resulted in eradication of H pylori and the return to normal of giant folds and the mucosal histology. Serum protein concentrations returned to normal within six weeks and remained normal at two endoscopies during a two year follow up. This case report suggests that a subgroup of the patients with Ménétrier's disease may be healed by the eradication of H pylori.

The waist-to-hip ratio corrected for body mass index is related to serum triglycerides and high-density lipoprotein cholesterol but not to parameters of glucose metabolism in healthy premenopausal women

Android obesity is associated with metabolic disorders, but the causality of this relationship remains unclear. We investigated the association of body mass index (BMI) and waist-to-hip ratio (WHR) with hormones, glucose tolerance, insulin sensitivity, serum lipoproteins, and the serum activity of hepatic enzymes in 40 healthy premenopausal women (BMI 19.2-46.1, mean 32.6 +/- 1.3 kg/m2; WHR 0.68-1.01, mean 0.82 +/- 0.02). BMI correlated with WHR (r = 0.52, P < 0.01). After correction for WHR, BMI was negatively correlated with high-density lipoprotein cholesterol and positively with total and very low density lipoprotein triglycerides, insulin sensitivity, blood glucose, serum insulin and glucagon. After adjustment for BMI, WHR was significantly associated with high-density lipoprotein cholesterol, total and very low density lipoprotein triglycerides, and the serum activities of hepatic enzymes but not with insulin sensitivity, blood glucose, serum insulin, or glucagon. According to these results, body fat distribution assessed by WHR is related to hypertriglyceridemia and alterations in hepatic function such as a fatty liver. WHR is not primarily related to glucose metabolism in healthy premenopausal women without preexisting metabolic disorders such as glucose intolerance. Therefore the observable association between android obesity and manifest impairment in glucose metabolism may develop secondarily during persisting hyperinsulinemia, which itself is primarily related to obesity. Thus an android body fat distribution may rather be an accompanying feature than a predictor of impaired glucose tolerance and insulin resistance.

Three-year treatment of familial heterozygous hypercholesterolemia by extracorporeal low-density lipoprotein immunoadsorption with polyclonal apolipoprotein B antibodies

Familial hypercholesterolemia is a disorder of lipid metabolism associated with a highly increased risk for cardiovascular disease. Since in such patients even combined drug therapy often fails to decrease low-density lipoprotein (LDL) cholesterol levels sufficiently, extracorporeal LDL elimination has been developed. We treated eight adult patients with LDL immunoadsorption using antibodies against apolipoprotein B without additional lipid-lowering drug therapy for 3 years; this procedure was performed at weekly intervals. By one treatment session, LDL cholesterol and lipoprotein(a) levels were decreased by 55%. Under regular treatment, mean LDL cholesterol levels of 165 mg/dL between two consecutive treatment sessions could be reached, compared with 522 +/- 24 mg/dL before any treatment. As high-density lipoprotein (HDL) cholesterol levels increased under regular treatment, the LDL/HDL cholesterol ratio decreased from 13.4 to 3.4. Positive influences on plasma and whole-blood viscosity as well as on erythrocyte aggregation also seem to be beneficial with regard to retarding atherosclerosis. Very-low-density lipoprotein (VLDL) levels were reduced by approximately 50% after treatment, accompanied by a marked increase of lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) activity. The effects of LDL apheresis on hemostasis, complement activation transport proteins, and hematological parameters were found to be small. In addition, no side effects amounting to any major clinical relevance occurred in any of the patients. After 3 years of LDL apheresis, a decrease in the frequency of anginal chest pain and ST segment depression on exercise testing and a marked reduction of tendon xanthoma size were observed.

Influence of fiber, xylitol and fructose in enteral formulas on glucose and lipid metabolism in normal subjects

To verify the benefit of nonglucose carbohydrates and fiber in enteral formula diets we studied the postprandial metabolism of eight healthy subjects after the intake of two helpings (25 g carbohydrates each) of five commonly used enteral formulas over 4 h. There were no significant differences in postprandial concentrations of blood glucose among the formulas. The area under the curve of postprandial insulin values, however, was significantly smaller after consumption of the fructose-containing formula (1948 +/- 285 microU min ml-1, P < 0.05) than after fiber-free (3222 +/- 678 microU min ml-1) or two fiber-containing products (2664 +/- 326 microU min ml-1, P < 0.05; and 3040 +/- 708 microU min ml-1, P < 0.05). The insulin area of the xylitol-containing formula (2307 +/- 364 microU min ml-1) was significantly smaller compared to the fiber-free product (P < 0.05). In addition, we found the postprandial increase in triglycerides to be significantly higher after the xylitol-containing formula (from 0.93 +/- 0.14 to 1.25 +/- 0.22 mmol/l) than after the fiber-free product (from 0.82 +/- 0.13 to 0.97 +/- 0.16 mmol/l, P < 0.05) or the two fiber-containing products (from 0.88 +/- 0.16 to 0.96 +/- 0.18 mmol/l, P < 0.05; and from 0.80 +/- 0.08 to 0.95 +/- 0.10 mmol/l, P < 0.05). We conclude that a patient with type II diabetes may benefit from replacing glucose and glucose-equivalent carbohydrates with fructose or xylitol.

Lipoprotein(a) in diabetes mellitus

Epidemiologic studies have identified lipoprotein(a) (Lp(a)) as an independent risk factor for atherosclerosis, mainly for coronary heart disease. Atherosclerosis is the most common cause of death in diabetic patients, but there is little information available concerning the importance of Lp(a) in these patients. We compared the presence or absence of late diabetic complications with Lp(a) serum concentrations in 224 patients (82 IDDM, 142 NIDDM). Lp(a) distribution was skewed as described for non-diabetic patients. Despite highly significant differences for total cholesterol, total triglycerides, HDL-cholesterol, VLDL-cholesterol and VLDL-triglycerides (P < 0.001) and for LDL-cholesterol (P < 0.01) Lp(a) concentrations were similar in NIDDM and IDDM (mean: 27 vs. 30, median: 12 vs. 21 mg/dl, P = 0.10). Diabetic polyneuropathy, autonomic neuropathy, nephropathy, peripheral occlusive disease, diabetic gangrene and coronary heart disease were not associated with raised Lp(a) values. Non-insulin-dependent patients with retinopathy exhibited higher Lp(a) concentrations in serum than those without this complication. This significant association was lost when duration of diabetes was taken into account by logistic regression. We conclude, that other risk factors surpass the significance of Lp(a) in diabetic patients.

[Characteristics of obese patients in intensive care]

BASIC REMARKS

The frequency of overweight, together with the associated increase in morbidity--in particular coronary heart disease--means that such patients often require intensive care.

MAIN POINTS DISCUSSED

The particular features of intensive care of obese patients are the increased risk of aspiration pneumonia (in the presence of lowered pH and elevated gastric juice volume), respiratory insufficiency caused by a reduction in expiratory reserve volume, and a greater incidence of thrombosis and embolism. Ventricular hypertrophy and dilatation results in a reduced cardiac reserve. A clinically unrecognized insulin resistance may become manifest during intensive care. Digoxin, theophylline and aminoglycosides, commonly with a low therapeutic spectrum, when administered on the basis of weight, may lead to dangerously high serum concentrations in the overweight.

CONCLUSIONS

At a weight of more than about 100 kg, it must generally be expected that the compensatory mechanisms of the body are exhausted and that there will be an increased susceptibility to additional disorders of homeostasis.

[Effects of beta blockers on lipoprotein metabolism]

PROBLEM

With respect to prevention of its most common complication--mortality from coronary heart disease--treatment of hypertension had disappointed. It is possible that this is due to negative effects of antihypertensives on lipid metabolism.

MAJOR TOPICS

The effects of beta blockers on lipid metabolism can be differentiated principally, in accordance with the classification of beta blockers into those with and those without intrinsic sympathomimetic activity (ISA), as also selectivity and non-selectivity. Thus, non-selective beta blockers with no ISA usually lead to an increase in triglycerides of 25% to 30%, and a decrease in HDL cholesterol of about 15%. On average, beta-1 selective blockers result in a smaller increase in triglycerides. Beta blockers with ISA, in contrast, are largely neutral vis-à-vis lipid metabolism. In the individual case, in particular in the presence of hyperlipoproteinemia, the effects cannot be reliably predicted.

CONCLUSIONS

Lipoprotein concentrations should be monitored during treatment with beta blockers. If necessary, a change in the agent employed is recommended. In the case of prevention of a second myocardial infarction, for which various studies have unequivocally shown a reduction in mortality associated with treatment with beta blockers with no ISA, these side effects will, however, be accepted--with the exception of extreme changes--for a limited period of time.

Treatment of primary chylomicronemia due to familial hypertriglyceridemia by omega-3 fatty acids

Primary familial forms of chylomicronemia can lead to acute life-threatening complications, especially acute pancreatitis. The main aim of therapy is to avoid this so-called chylomicronemia syndrome. In 12 patients with primary chylomicronemia due to familial hypertriglyceridemia, the addition of 2.16 g omega-3 fatty acids over 4 weeks and 4.32 g for 8 weeks resulted in a decrease of serum triglyceride levels from 1,624 +/- 333 to 894 +/- 241 mg/dL after 12 weeks. Cholesterol and triglyceride levels in the chylomicron fraction were reduced concomitantly, the apolipoprotein B-100/B-48 ratio increased, very--low-density lipoprotein (VLDL) triglycerides, VLDL cholesterol, and total cholesterol levels decreased, and low-density lipoprotein (LDL) cholesterol showed a tendency to increase, but this finding did not reach significance. High-density lipoprotein (HDL) cholesterol levels remained unchanged, as did the levels of apolipoproteins A-I, A-II, and E, and lipoprotein(a). Apolipoprotein B levels decreased significantly. The decrease of triglyceride levels to still-elevated concentrations was accompanied by a substantial decrease in plasma and whole-blood viscosity and erythrocyte aggregation, which reached normal values. As in chylomicronemia, complications usually occur at triglyceride levels higher than 1,500 mg/dL; patients can still profit from treatment with omega-3 fatty acids, even though triglyceride levels are still substantially elevated. No clinically relevant side effects occurred, with the exception of the manifestation of diabetes mellitus in one patient, which could be reversed after discontinuation of treatment.

Granulocytes and three-phase bone scintigraphy for differentiation of diabetic gangrene with and without osteomyelitis

OBJECTIVE

In diabetic gangrene, concomitant osteopathy and soft-tissue infection often render laboratory and roentgenographic signs unreliable as indicators of osteomyelitis. In this situation, scintigraphic methods can be helpful.

RESEARCH DESIGN AND METHODS

Relying on the long-term clinical course as the final indicator of presence or absence of osteomyelitis, we prospectively compared in 31 patients three-phase bone scintigraphy with either indium-labeled autologous granulocytes (n = 20) or 123I-labeled antibodies against granulocytes (n = 11).

RESULTS

Three-phase bone scintigraphy and imaging with indium-labeled autologous granulocytes yielded sensitivities and specificities of 95 and 70% for bone scintigraphy and 77 and 100% for granulocyte scintigraphy, respectively. One patient with severe angiopathy and proved osteomyelitis had a negative bone scintigraphy but a positive scintigraphy with labeled antibodies against granulocytes. One patient with aseptic bone necrosis presented with a formally false positive result with both methods.

CONCLUSIONS

In contrast to former retrospective studies, three-phase bone scintigraphy compares very well with granulocyte scintigraphy. The care of most patients can be managed with clinical data and this widely available scintigraphic method.