Lipids of Erythrocyte Membranes of COPD Patients: A Quantitative and Qualitative Study

Figures & data

Table 1.  Clinicophysiological parameters of the subjects

	Healthy non-smokers (N = 10)	Healthy Smokers (N = 10)	COPD group I (N = 10)	COPD group II (N = 10)	COPD group III (N = 10)
Age*	30.8 ± 6.37 (24–42)	42.9 ± 11.14 (28–60)	55.2 ± 5.98 (48–65)	57.4 ± 6.95 (42–65)	56.7 ± 6.27 (46–63)
Sex(M:F)	7:3	10:0	9:1	10:0	10:0
Duration of illness*	Nil	Nil	4.7 ± 3.95 (1–12)	6.9 ± 4.73 (2–16)	5.9 ± 2.85 (2–9)
Cigarette Smokers	Nil	10	6	7	6
Bidi smokers	Nil	Nil	Nil	2	1
Both Bidi and Cigarette	Nil	Nil	1	1	3
Non-Smokers	10	Nil	3	0	0
Duration of smoking*	Nil	22.6 ± 3.67 (6–35)	19.5 ± 14.42 (0–40)	26.6 ± 7.82 (10–35)	24.8 ± 5.61 (20–35)
FEV1%	N.D.	N.D.	59 ± 4.40	38.4 ± 5.74	24.1 ± 3.25
FVC%	N.D.	N.D.	88.8 ± 9.62	74.0 ± 11.60	72.0 ±17.45
FEV1/FVC%	N.D.	N.D.	57.1 ± 5.22	46.1 ± 7.42	35.7 ± 8.81

*Values expressed in years.

Data in parentheses represent range.

M = males, F = females.

Pulmonary function data expressed in% of predicted value.

N.D. = not done.

Figure 1.  Cholesterol (Chol) and Phospholipid (PL) contents of erythrocyte membrane (expressed as μg/mg proteins) H = Healthy non-smokers, S = Healthy smokers, Group I = patients of COPD stage II, Group II = Patients of COPD stage III, Group III = Patients of COPD stage IV. N = 10 in each group. Data represented as mean ± S.E.M.

Figure 2.  Correlation between FEV1% and total cholesterol of erythrocyte membrane. The cholesterol is expressed as μg/mg membrane proteins.

Figure 3.  Correlation between FEV1% and total phospholipid (PL) of erythrocyte membrane of all stages of COPD combined. The PL is expressed as μg/mg membrane proteins.

Figure 4.  Phosphatidylethanolamine (PE) and phosphatidylcholine (PC) contents of the erythrocyte membrane (expressed as μg/mg proteins). H = Healthy non-smokers, S = Healthy smokers, Group I = Patients of COPD stage II, Group II = Patients of COPD stage III, Group III = Patients of COPD stage IV. N = 10 in each group. Data represented as mean ± S.E.M.

Figure 5.  Chromatogram of fatty acid analysis of phosphatidylcholine (PC) as representative of the phospholipids of erythrocyte membrane in various groups of patients having COPD (Group I-III), healthy smokers (S) and healthy non-smokers (H). H = Healthy non-smokers, S = Healthy smokers, Group I = Patients of COPD stage II, Group II = Patients of COPD stage III, Group III = Patients of COPD stage IV.

Table 2.  Fatty acid composition of erythrocyte membrane of acidic phospholipids (Phoshatidylinositide, Phosphatidylserine)

	Healthy non-smoker (N = 10)	Healthy smoker (N = 10)	COPD Patients
			Group I (N = 10)	Group II (N = 10)	Group III (N = 10)
Fatty acid in Phoshatidylinositides (PI)
C 16:00	0.203±0.012 (0.140–0.256)	0.328±0.047 (0.171–0.603)	0.512±0.074* (0.177–0.841)	0.365±0.071 (0.154–0.904)	0.349±0.052 (0.186–0.642)
C 18:00	0.388±0.023 (0.228–0.456)	0.512±0.067 (0.294–0.944)	0.517±0.073 (0.189–0.920)	0.348±0.066 (0.147–0.834)	0.285±0.043 (0.155–0.553)
C 18:01	0.277±0.019 (0.187–0.371)	0.414±0.056 (0.229–0.776)	0.332±0.044 (0.120–0.535)	0.207±0.040 (0.089–0.508)	0.137±0.020 (0.077–0.243)
C 18:02	0.581±0.041 (0.375–0.762)	Nil	Nil	Nil	Nil
C 20:00	Nil	0.264±0.035 (0.146–0.501)	0.299±0.041 (0.110–0.507)	0.204±0.040 (0.089–0.506)	0.167±0.025 (0.090–0.316)
C 22:00	Nil	0.516±0.092 (0.259–1.157)	0.454±0.056 (0.178–0.749)	0.324±0.064 (0.144–0.818)	0.264±0.040 (0.146–0.491)
Fatty acid in Phosphatidylserine (PS)
C 16:00	0.194±0.004 (0.179–0.225)	0.192±0.003 (0.176–0.215)	0.303±0.008** (0.276–0.366)	0.361±0.012** (0.317–0.418)	0.412±0.008** (0.384–0.472)
C 18:00	0.360±0.005 (0.344–0.389)	0.355±0.005 (0.335–0.386)	0.371±0.009 (0.342–0.439)	0.360±0.010 (0.325–0.412)	0.368±0.007 (0.335–0.406)
C 18:01	0.287±0.004 (0.269–0.315)	0.283±0.004 (0.260–0.306)	0.214±0.005** (0.201–0.257)	0.160±0.004** (0.144–0.184)	0.143±0.003** (0.124–0.157)
C 18:02	0.600±0.010 (0.559–0.662)	Nil	Nil	Nil	Nil
C 20:00	Nil	0.187±0.003 (0.177–0.207)	0.200±0.005 (0.186–0.240)	0.195±0.005 (0.177–0.223)	0.200±0.004 (0.181–0.225)
C 22:00	Nil	0.336±0.005 (0.316–0.370)	0.339±0.008 (0.314–0.407)	0.327±0.010 (0.293–0.384)	0.336±0.006 (0.314–0.372)

C 16:00 = Palmitic acid, C18:00 = Stearic acid, C18:01 = Oleic acid, C18:02 = Linoleic acid, C20:00 = Arachidic acid and C22:00 = Behenic acid.

Values are expressed as μg fatty acid/μg of phospholipids (mean ± S.E.M.). Data in parenthesis show range.

* P < 0.01, ** P < 0.001, as compared to healthy non-smokers.

Table 3.  Fatty acid composition of erythrocyte membrane neutral phospholipids (Phoshatidylcholine, Phoshatidylethanolamine)

	Healthy non-smoker (N = 10)	Healthy smoker (N = 10)	COPD Patients
			Group I (N = 10)	Group II (N = 10)	Group III (N = 10)
Fatty acid in Phoshatidylcholine (PC)
C 16:00	0.361±0.002 (0.355–0.375)	0.354±0.004 (0.336–0.372)	0.382±0.003* (0.367–0.395)	0.409±0.002** (0.397–0.421)	0.459±0.009** (0.422–0.513)
C 18:00	0.313±0.004 (0.290–0.338)	0.303±0.005 (0.276–0.333)	0.324±0.004 (0.312–0.357)	0.326±0.003 (0.308–0.341)	0.319±0.004 (0.300–0.344)
C 18:01	0.210±0.002 (0.195–0.219)	0.210±0.003 (0.197–0.225)	0.183±0.001** (0.179–0.191)	0.175±0.004** (0.150–0.188)	0.171±0.003** (0.149–0.181)
C 18:02	0.807±0.013 (0.743–0.860)	Nil	Nil	Nil	Nil
C 20:00	Nil	0.261±0.003 (0.243–0.275)	0.247±0.002*** (0.242–0.266)	0.247±0.002*** (0.236–0.255)	0.242±0.002*** (0.231–0.253)
C 22:00	Nil	0.168±0.004 (0.152–0.184)	0.219±0.003* (0.200–0.237)	0.218±0.003* (0.202–0.234)	0.214±0.003* (0.199–0.235)
Fatty acid in Phoshatidylethanolamine (PE)
C 16:00	0.233±0.002 (0.214–0.237)	0.244±0.014 (0.219–0.366)	0.323±0.003** (0.310–0.343)	0.359±0.004** (0.342–0.376)	0.390±0.005** (0.371–0.415)
C 18:00	0.389–0.002 (0.375–0.398)	0.370±0.014 (0.251–0.396)	0.365±0.006 (0.340–0.389)	0.386±0.006 (0.352–0.414)	0.380±0.003 (0.367–0.400)
C 18:01	0.192±0.003 (0.176–0.208)	0.204±0.011 (0.176–0.300)	0.175±0.001** (0.170–0.180)	0.158±0.001** (0.152–0.163)	0.117±0.002** (0.103–0.124)
C 18:02	0.667±0.004 (0.656–0.700)	Nil	Nil	Nil	Nil
C 20:00	Nil	0.207±0.005 (0.187–0.247)	0.226±0.006 (0.210–0.267)	0.226±0.006 (0.209–0.269)	0.220±0.006 (0.204–0.268)
C 22:00	Nil	0.323±0.006 (0.289–0.341)	0.321±0.003 (0.300–0.337)	0.326±0.005 (0.301–0.351)	0.318±0.004 (0.299–0.345)

C 16:00 = Palmitic acid, C18:00 = Stearic acid, C18:01 = Oleic acid, C18:02 = Linoleic acid, C20:00 = Arachidic acid and C22:00 = Behenic acid.

Values are expressed as μg fatty acid/μg of phospholipids (mean ± S.E.M.). Data in parenthesis show range.

*P < 0.05, **P < 0.001 as compared to healthy non-smokers, ***P < 0.01, as compared to healthy smokers.

Table 4.  Fatty acid composition of erythrocyte membrane sphingomyelin (Sph)

	Healthy non-smoker (N = 10)	Healthy smoker (N = 10)	COPD Patients
			Group I (N = 10)	Group II (N = 10)	Group III (N = 10)
Fatty acids in Sph
C 16:00	0.270±0.003 (0.252–0.285)	0.290±0.024 (0.257–0.505)	0.310±0.004 (0.291–0.338)	0.377±0.004* (0.351–0.397)	0.418±0.007* (0.395–0.450)
C 18:00	0.419±0.004 (0.403–0.438)	0.451±0.004 (0.396–0.772)	0.382±0.004 (0.370–0.401)	0.375±0.004 (0.358–0.398)	0.385±0.006 (0.359–0.420)
C 18:01	0.207±0.003 (0.184–0.214)	0.227±0.015 (0.199–0.357)	0.166±0.002* (0.162–0.177)	0.136±0.002* (0.128–0.149)	0.121±0.003* (0.113–0.139)
C 18:02	1.036±0.020 (0.923–1.114)	Nil	Nil	Nil	Nil
C 20:00	Nil	0.350±0.024 (0.302–0.561)	0.322±0.004 (0.309–0.343)	0.328±0.003 (0.310–0.341)	0.333±0.005 (0.319–0.372)
C 22:00	Nil	0.285±0.025 (0.247–0.511)	0.254±0.005 (0.232–0.280)	0.262±0.005 (0.236–0.279)	0.270±0.004 (0.251–0.296)

C 16:00 = Palmitic acid, C18:00 = Stearic acid, C18:01 = Oleic acid, C18:02 = Linoleic acid, C20:00 = Arachidic acid and C22:00 = Behenic acid.

Values are expressed as μg fatty acid/μg of phospholipids (mean ± S.E.M.). Data in parenthesis show range.

*P < 0.001, as compared to healthy non-smokers.

Table 5.  Lipid ratios in erythrocyte membranes

	Healthy non-smoker (N = 10)	Healthy smoker (N = 10)	COPD Patients
			Group I (N = 10)	Group II (N = 10)	Group III (N = 10)
PL/Prot	283.4 ± 20.5 (166.92–365.19)	349.4 ± 13.15 (310.49–423.16)	322.3 ± 19.06 (227.27–406.18)	342.2 ± 16.22 (275.59–443.75)	409.0 ± 17.93* (321.61–507.12)
Sph/PC	0.916 ± 0.023 (0.86–1.09)	0.884 ± 0.021 (0.76–1.04)	0.905 ± 0.016 (0.80–0.96)	0.886 ± 0.023 (0.79–1.0)	0.822 ± 0.026** (0.68–0.91)
Chol/PL	0.414 ± 0.014 (0.35–0.51)	0.413 ± 0.006 (0.39–0.46)	0.432 ± 0.016 (0.37–0.51)	0.424 ± 0.021 (0.35–0.56)	0.412 ± 0.025 (0.35–0.55)
PC/Chol	0.696 ± 0.021 (0.553–0.818)	0.677 ± 0.021 (0.581–0.796)	0.689 ± 0.023 (0.572–0.815)	0.706 ± 0.023 (0.636–0.880)	0.703 ± 0.014 (0.612–0.781)
Sph/Chol	0.636 ± 0.022 (0.543–0.792)	0.598 ± 0.022 (0.467–0.705)	0.622 ± 0.018 (0.523–0.726)	0.621 ± 0.012 (0.563–0.710)	0.577 ± 0.020 (0.459–0.657)
PC/PE	1.052 ± 0.004 (1.024–1.066)	1.081 ± 0.022 (0.989–1.183)	1.051 ± 0.008 (0.985–1.082)	1.047 ± 0.024 (0.967–1.242)	1.075 ± 0.018 (1.000–1.189)

PL (Total Phospholipids), Prot (Proteins), Sph (Sphingomyelin), PC (Phosphatidylcholine), Chol (Cholesterol), PE (Phospatidylethanolamine) of erythrocyte membranes.

*P = 0.018.

**P = 0.045.