A commercial assay for apolipoproteins A-1 and B as well as total cholesterol, triglyceride, and high-density lipoprotein (HDL) cholesterol was applied to 12-hour fasted serum from 24 insulin-dependent and 19 noninsulin-dependent diabetic persons. Women with noninsulin-dependent diabetes mellitus (NIDDM) had the highest levels of total cholesterol and apolipoprotein B. Apolipoprotein B values fell within the normal range in all patients except the NIDDM females, where four of the ten (40%) samples were elevated. When apolipoprotein B was elevated, total cholesterol was also elevated, over 220 mg/dL. Apolipoprotein A-1 values fell within or above the normal range in all subjects, and a considerable discordance was observed between apolipoprotein A-1 elevations and HDL cholesterol elevations. The divergence between HDL cholesterol and apolipoprotein A-1 supports the altered composition of HDL in the diabetic persons studied. Further study should elucidate the clinical usefulness of apolipoprotein measurements in diabetic patients

Fachnie, J. David

Foreback, Craig

Kahkonen, Dorothy M.

McGill, Janet

English

Henry Ford Health System Scholarly Commons

Henry Ford Hospital Medical Journal Volume 34 Number 2 Article 11 6-1986 The Clinical Usefulness of Measuring Apolipoproteins in Diabetic Patients: A Preliminary Report J. David Fachnie Janet McGill Craig Foreback Dorothy M. Kahkonen Follow this and additional works at: https://scholarlycommons.henryford.com/hfhmedjournal  Part of the Life Sciences Commons, Medical Specialties Commons, and the Public Health Commons Recommended Citation Fachnie, J. David; McGill, Janet; Foreback, Craig; and Kahkonen, Dorothy M. (1986) "The Clinical Usefulness of Measuring Apolipoproteins in Diabetic Patients: A Preliminary Report," Henry Ford Hospital Medical Journal : Vol. 34 : No. 2 , 113-116. Available at: https://scholarlycommons.henryford.com/hfhmedjournal/vol34/iss2/11 This Article is brought to you for free and open access by Henry Ford Health System Scholarly Commons. It has been accepted for inclusion in Henry Ford Hospital Medical Journal by an authorized editor of Henry Ford Health System Scholarly Commons. Original Contributions Xhe Clinical Usefulness of Measuring Apolipoproteins in Diabetic patients: A Preliminary Report* J. David Fachnie, MD,+ Janet McGill, MD,* Craig Foreback, PhD,§ and Dorothy M. Kahkonen, MD* A commercial assay for apolipoproteins A-l and B as well as total cholesterol, triglyceride, and high-density lipoprotein (HDL) cholesterol was applied to 12-hour fasted serum from 24 insulin-dependent and 19 noninsulin-dependent diabetic persons. Women with noninsulin-dependent diabetes mellitus (NIDDM) had the highest levels of total cholesterol and apolipoprotein B. Apolipoprotein B values fell within the normal range in all patients except the NIDDM females, where four of the ten (40%) samples were elevated. When apolipoprotein B was elevated, total cholesterol was also elevated, over 220 mg/dL. Apolipoprotein A-l values fell within or above the normal range in all subjects, and a considerable discordance was observed between apolipoprotein A-l elevations and HDL cholesterol elevations. The divergence between HDL cholesterol and apolipoprotein A-l supports the altered composition of HDL in the diabetic persons studied. Further study should elucidate the clinical usefulness of apolipoprotein measurements in diabetic patients. (Henry FordHosp MedJ 1986;34:113-6) When a commercial assay for apolipoproteins A-1 and B be-came available, we wondered how this additional infor-mation could be used to evaluate risk for atherosclerosis in our diabetic patients. In nondiabetic persons, apolipoprotein A-l was claimed to better discriminate those with and without coro-nary-artery disease than high-density lipoprotein (HDL) cho-lesterol (1). However, in persons with noninsulin-dependent diabetes mellitus (NIDDM), a divergence between apolipopro-tein A-l and HDL cholesterol suggested that such comparisons may yield different results in diabetic subjects (2). Our prelimi-nary experience with measuring apolipoproteins A-l and B in diabetic patients and relating these measurements to commonly measured triglyceride, cholesterol, and HDL cholesterol is described. Materials and Methods In our clinic, the 43 ambulatory patients with NIDDM and IDDM (insulin-dependent diabetes mellitus) who donated 12-hour fasted blood specimens had the following characteristics: 1) IDDM female, mean age 30 years, mean BMI (body mass index) 26.6, N = 9; 2) IDDM male, mean age 30 years, mean BMI 26.7, N = 15; 3) NIDDM female, mean age 58 years, mean BMI 33.0, N = 9; 4) NIDDM male, mean age 56 years, mean BMI 27.6, N = 9; and 5) nondiabetic persons, N = 15. Pasting serum was assayed for triglyceride, cholesterol, and HDL cholesterol using standard methods (3-5). Glycosylated hemoglobin was mn by high pressure liquid chromatography by American Bio-Science Laboratories (Farmington Hills, MI). 'Apolipoproteins A-l and B were assayed with a commercial as-say by ligand combined with nephilometry. In this assay, apo-•^ snry Ford Hosp Med J—Vol 34, No 2, 1986 lipoproteins A- l and B in serum react with specific antisera prepared against purified apolipoproteins A-l and B. The result-ing antigen-antibody complex increases the turbidity in the solu-tion. A beam of collimated, monochromatic light from a laser source is passed through the solution, and the antigen-antibody complexes produce light scatter. The forward light scatter is measured quantitatively in relative light scatter units and is pro-portional to the amount of antigen in the sample (6,7). The data were subjected to statistical analysis including com-putation of mean, standard deviation, analysis of variance, paired comparison for significant results, and correlation coeffi-cients (Pearson Product Moment) (8). Further evaluation of the data for clinical usefulness was made by comparing the total semm cholesterol, HDL cholesterol, and apolipoprotein A-l and B values with available reference ranges. Total semm cholesterol values were compared to the "moderate risk" for coronary-artery disease category of the Consensus Conference on Lowering Blood Cholesterol, ie, 75th to 90th percentile for the Lipid Research Clinic's Prevalence Study (9). Levels greater than 220 mg/dL were considered to be elevated. HDL cholesterol levels were compared with Framingham values Submitted for publication: December 19, 1985. Accepted for publication: January 3, 1986. •Presented in part to American College of Physicians Regional Meeting, Traverse City, Ml, September 1985. tDepartment of Intemal Medicine, Metabolic Diseases Division, Henry Ford Hospital. tDepartment of Intemal Medicine, Metabolic Diseases Division, Washington Univer-sity, St Louis, MO. §Department of Clinical Chemistry, Henry Ford Hospital. Address correspondence to Dr Fachnie, Department of Intemal Medicine, Henry Ford Hospital, 2799 W Grand Blvd, Detroit. Ml 48202. Measuring Apolipoproteins in Diabetics—Fachnie et al 113 E O QC LU H CO Ul _J O I o _ l c T 110 100 90 80 7 0 -6 0 -50 -4 0 -30 -20 -100 I; 55-45-9 0 - 9 NORMAL RANGE Fig 1—High-density lipoprotein cholesterol in IDDM and NIDDM patients. I = IDDM patients and II = NIDDM patients. (10). Lower HDL cholesterol was shown to increase the risk for coronary-artery disease. Depressed HDL cholesterol was de-fined as less than 45 mg/dL for males and less than 55 mg/dL for females. Desired ranges for apolipoproteins were defined by our clinical laboratory as follows: 35 to 147 mg/dL for apolipopro-tein B and 95 to 152 mg/dL for apolipoprotein A- l . Higher levels of apolipoprotein A-1 and lower levels of apolipoprotein B are supposedly related to a decreased risk for coronary-artery dis-ease in nondiabetic persons (11-14). Results The degree of adiposity, as measured by BMI (kg/m-^ ) and analyzed by Student's t-test, was not significantly different be-tween our IDDM and NIDDM subjects of the same sex. The glycosylated hemoglobin, an index of blood sugar control, also was not significantly different between groups when subjected to analysis of variance. Using analysis of variance, the mean cholesterol and apolipoprotein B were significantly different, p < 0.05, be-tween diabetic subgroups (Table). A paired comparison for sig-nificant results revealed that cholesterol was significantly greater in NIDDM females than in NIDDM males. Also, apolipopro-tein B was significantly greater in NIDDM females than in NIDDM males, IDDM males, and IDDM females. Correlation coefficients between commonly measured cho-lesterol, triglyceride, and HDL cholesterol and the apolipo-protein measures were strongly positive: cholesterol and apolipoprotein B (0.832), low-density lipoprotein (LDL) cholesterol and apolipoprotein B (0.650), HDL cholesterol and apolipoprotein A-l (0.786), and triglyceride and apolipoprotein B (0.806). Total semm triglycerides were within the laboratory normal range (40 to 160 mg/dL) for IDDM males and females. Eleva-tions were observed in four of eight (50%) NIDDM males and four of seven (57%) NIDDM females. Total semm cholesterol values were elevated in four of nine (44%) IDDM males, three of five (80%) IDDM females, two of eight (25%) NIDDM males, and four of eight (50%) NIDDM females. HDL cholesterol was low, less than 55 mg/dL, in two of four (50%) IDDM females and in five of seven (71%) NIDDM females. HDL cholesterol was low, less than 45 mg/dL, in six of ten (60%) IDDM males and in four of eight (50%) NIDDM males (Fig 1). Apolipoprotein B values fell within the normal range in almost all subjects except for NIDDM females, where four of ten (40%) values were elevated over 147 mg/dL. When apolipo-protein B was elevated, total cholesterol was also elevated, over 220 mg/dL. All apolipoprotein A-l values fell within or above the normal range (Fig 2). Elevations were observed in 11 of 15 (73%) IDDM males, three of eight (38%) IDDM females, seven of nine (78%) NIDDM males, and seven of ten (70%) NIDDM females. An elevation in apolipoprotein A-l was frequentiy found in the same subject when HDL cholesterol was not elevated. This discor-dance was not seen in IDDM females, but was observed in six of Table Serum Cholesterol, Ti-iglyceride, HDL Cholesterol, and Apolipoproteins* Number of Glycosylated HDL Subjects Hemoglobin Cholesterol Triglycerides Cholesterol Apolipoproteins B A - l IDDM Male 15 10.9 (4)t 199 ± 43 107 ± 68 41.7 ± 6.0 78 ' 3() 155 ± 20 IDDM Female 9 12.2(5) 211 ± 4 6 76 ± 17 62.0 ± 30.0 73 ± 31 161 ± 45 NIDDM Male 9 8.8 (4) 189 ± 40 160 ± 104 45.7 ± 17.5 78.5 ± 44 180 ± 34 NIDDM Female 10 10.6(5) 246 ± 311 180 ± 91 42.9 ± 13.7 142* ± 56 166 ± 39 Nondiabetic sample l.^ 78 ± 23 153 ± 21 Reference normal ranges 6-8.8 140-220 40-160 45 male 55 female 35 -147 95 •152 *A1I numbers are mean ± I standard deviation in mg/dL except glycosylated hemoglobin, which is a percentage. tNumber inside parentheses indicates number of subjects. tp < 0.05. See text for explanation. IDDM ^ insuhn-dependent diabetes mellitus. NIDDM = noninsulin-dependent diabetes mellitus. 114 Henry Ford Hosp Med J—Vol 34, No 2, 1986 Measuring ApoIipt)proteins in Diabetics—Fachnie el al Henry •ne (66%) IDDM males, three of five (60%) NIDDM females, f " j j^ two of six (33%) NIDDM males. Discussion The prevalence of coronary-artery disease is 1.2 to 6.6 times (ligher in diabetic persons than the general population (15). Ac-curate determination of risk factors should help the physician to modify this poor outcome. Unfortunately, diabetes mellitus modifies the lipid phenotype in rather complex ways. Variables such as age, sex, type of diabetes mellitus, and state of diabetic control must be considered. Reference ranges for nondiabetic nersons may not have the same meaning for diabetic persons. Our diabetic subgroups did not differ in degree of adiposity or estimate of diabetes control by glycosylated hemoglobin. The present study represents a preliminary evaluation of apolipoproteins A-l and B in our metabolism clinic. The pa-tients selected, although few, were more or less representative of our population of diabetic patients. We evaluated our data with regard to three questions: 1) What is the prevalence of abnormal lipid values in our sample? 2) What differences exist between NIDDM, IDDM, and gender? 3) What additional information of clinical value is provided by measurement of apolipoproteins A-l and B? Many of our diabetic subjects had abnormal lipid values. Tri-glycerides were elevated in 50%; to 57% of NIDDM subjects. Cholesterol was elevated in 25%) to 80% of all subjects. De-pressed HDL cholesterol occurred in over half of all diabetic persons studied. Regarding differences between subgroups, NIDDM females had elevation in both cholesterol and apolipoprotein B that reached statistical significance. Apolipoprotein B constitutes the major protein component of LDL. Elevations of apolipopro-tein B are related to the development of coronary-artery disease in nondiabetic persons (16). An excellent study by Walden et al, which included a large number of NIDDM and IDDM males and females compared to an age, sex, and weight matched control group, reported a sim-ilar profile of elevated cholesterol, triglyceride, and depressed HDL cholesterol in NIDDM females (17). Apolipoproteins were not available in that study. Our results are consistent with the view that NIDDM females have a particulariy atherogenic lipid profile and greater risk for coronary-artery disease (18). When determining what addirional information of clinical value was provided by apolipoprotein A-1 and B measurement when combined with triglycerides, cholesterol, and HDL cho-lesterol, we found a high correlation coefficient between total cholesterol and apolipoprotein B. Furthermore, when apo-lipoprotein B was elevated, cholesterol was also elevated. We concluded that the apolipoprotein B measures reinforced but did not supplement the clinical impression available from choles-terol measures alone. Apolipoprotein A-l is the major protein constituent of HDL. HDL cholesterol levels are inversely related to the risk for isch-emic heart disease. We have previously reported lower HDL cholesterol levels in diabetic persons with vascular disease (19). Therefore, we would expect to see depressed HDL cholesterol levels and correspondingly depressed apolipoprotein A-l in a sample of putative high-risk diabetic persons. In fact, we ob--Fachnieetllj 260-240-220 -— 5 200 -• > 5 180-CL < 140-120-100-: s * 152 92 9 cr 9 NORMAL RANGE '^ 'nry Ford Hosp Med J—Vol 34, No 2,1986 Fig 2—Apolipoprotein A-l in IDDM and NIDDM patients. I = IDDM patients and II = NIDDM patients. served a high correlation between HDL cholesterol and apolipoprotein A - l . However, the apolipoprotein A-l values were surprisingly high, while HDL cholesterol levels were nor-mal or depressed. The frequent discordance between these two values presents a problem that demands further study. For exam-ple, we can no longer accept the conclusion that apolipoprotein A-l is more useful than HDL cholesterol in identifying persons with coronary-artery disease (1). The conclusion may be pre-mature or may apply only to the nondiabetic patient. A similar trend of elevated apolipoprotein A-l levels despite relatively low HDL cholesterol has been previously observed in NIDDM women (2). An increase in HDL triglyceride without alteration in HDL particle number was used to explain this diver-gence. Other authors have also observed a divergence between HDL cholesterol and apolipoprotein A-l in IDDM patients (20). We concluded that the divergence between HDL cholesterol and apolipoprotein A-l supports the concept of an altered composi-tion of HDL in the diabetic persons studied. Further inves-tigation should focus on the composition of HDL and its relationship to atherosclerosis and other complications of di-abetes mellitus. The available data suggest that the clinical measurement of apolipoprotein B in diabetic persons will reinforce but not nec-essarily supplement the impression of coronary-artery disease risk provided by cholesterol alone. The measurement of apolipoprotein A- l , as an isolated value, may give a false im-pression of low risk. Accordingly, we cannot recommend the routine clinical measurement of apolipoproteins in diabetic per-sons at this time. Acknowledgments We gratefully acknowledge the support of Fred W. White-house, MD, who contributed patients and advice; Davida Kmger, RN, MSN, and Doris Fleming, RN, MSN, who assisted in data collection; Edward Petersen, MS, who performed statis-tical analysis; and Mary Reynolds, who typed the manuscript. Measuring Apolipoproteins in Diabetics—Fachnie et al 115 References 1. Maciejko JJ, Holmes DR, Kottke BA, Zinsmeister AR, Dinh DM, Mao ST. Apolipoprotein A-l as a marker of angiographically assessed coronary-artery disease. N Engl J Med 1983;309:385-9. 2. Biesbroeck RC, Albers JJ, Wahl PW, Weinberg CR, Bassett ML, Bierman EL. Abnormal composition of high density lipoproteins in non-insulin-depen-dent diabetics. Diabetes 1982;31:126-31. 3. Tiffany TO, Morton JM, Hall EM, Garrett AS Jr Clinical evaluation of kinetic enzymatic fixed-time and integral analysis of serum triglycerides. Clin Chem 1974;20:476-81. 4. Roschlar P, Bemt E, Gruber W. Enzymatic determination of total choles-terol in semm using peroxidase as indicating enzyme. Clin Chem 1975;21:941. 5. Kostner GM. Enzymatic determination of cholesterol in high-density lipoprotein fractions prepared by polyanion precipitation. Clin Chem 1976;22:695-6. 6. Product insert. Alert B LDL-Apolipoprotein B test kit, Hyland Diag-nostics, 1981. 7. Product insert. Alert A HDL-Apolipoprotein A,^  test kit, January 1983. 8. Christensen HB. Statistics step by step. Boston: Houghton Mifflin Com-pany, 1977. 9. Bemstein MJ. Consensus conference: Lowering blood cholesterol to pre-vent heart disease. JAMA 1985;253:2080-6. 10. Kannel WB, Castelli UP, Gordon T. Cholesterol in the prediction of ath-erosclerotic heart disease. New perspectives based on the Framingham study. Ann Intem Med 1979;90:85-91. 11. Avagaro P, Bittolo Bon G, Cazzalato G, Quincy G. Are apolipoproteins better discriminators than lipids for atherosclerosis? Lancet 1979;1:901-3. 12. Lopes-Virella MLF, Virella G, Evans G, Malenkos SB, Cozwell } \ Immunonephelometric assay of human apolipoprotein A - l . Clin Chem 1980;26:1205-8. 13. Albers JJ, Cabana VG, Hazzard WR. Immunoassay of human plasma apolipoprotein B. Metabolism 1975;24:1339-51. 14. Ballantyne FC, Williamson J, Shapiro D, Caslake MJ, Perry B. Estima-tion of apolipoprotein B in man by immunonephelometry. Clin Chem 1978;24:788-92. 15. FeinFS, Scheuer J. Heart disease in diabetics. In: Ellenberg M, RifkinH eds. Diabetes mellitus theory and practice. 3rd ed. New York: Medical Exam-ination Publishing Company, 1983:851-61. 16. WhayneTF, Alaupovic P, Curry MD, Lee ET, Anderson PS, SchechterE. Plasma apolipoprotein B and VLDL-, LDL-, and HDL-cholesterol as risk fac-tors in the development of coronary artery disease in male patients examined by angiography. Atherosclerosis 1981;39:411-24. 17. Walden CE, Knopp RH, Wahl PW, Beach KW, Strandness E Jr. Sex dif-ferences in the effect of diabetes mellitus on lipoprotein triglyceride and choles-terol concentrations. N Engl J Med I984;311:953-9. 18. Rytter L, Troelsen S, Beck-Nielsen H. Prevalence and mortality of acute myocardial infarction in patients with diabetes. Diabetes Care 1985;8:230-4. 19. Kahkonen D. Plasma lipid abnormalities in diabetes mellitus: Observa-tions on HDL cholesterol and recommendation for the management of lipid ab-nomialities. Henry Ford Hosp MedJ 1983;31:91-4. 20. Lopes-Virella ME Wohitman HJ, Mayfield RK, Loadholt CB, Colwell JA. Effect of metabolic control on lipid, lipoprotein and apolipoprotein levels in 55 insulin-dependent diabetic patients: A longitudinal study. Diabetes 1983;32:20-5. 116 Henry Ford Hosp Med J—Vol 34, No 2, 1986 1 i Measuring Apolipoproteins in Diabetics—Fachnie et al Frc hade fions lowei studii the h surge Po critei 2) el, He: nry 

The Clinical Usefulness of Measuring Apolipoproteins in Diabetic Patients: A Preliminary Report

https://scholarlycommons.henryford.com/cgi/viewcontent.cgi?article=2415&amp;context=hfhmedjournal

The Clinical Usefulness of Measuring Apolipoproteins in Diabetic Patients: A Preliminary Report

Abstract

Similar works

Full text

Available Versions

Henry Ford Health System Scholarly Commons