Connective Tissue in Varicose Veins Lupo Andreotti, M.D., and
Daniele Cammelli, M.D.
FLORENCE,
ITALY
A bstract The collagen, elastin, total sugar, and nonscleroprotein content was evaluated in 32 samples of saphenous varicose vein and in 34 controls. A significantly lower collagen and elastin content was found in the varicose samples without correlation with the degree of pathologic broadening. Otherwise the total sugars and the soluble nonscleroproteins were found to be increased in varicose samples. The results are more significant when expressed as milligrams per surface unit of endothelium. Our data support the hypothesis that the decrease in collagen and elastin content is a primary rather than secondary
change. Introduction A widespread concern has been arisen around Burkitt’s epidemiologic works’,’ about the possible implications of a low-fiber diet, peculiar of Western populations, in the pathogenesis of varicose veins of the lower limbs. Discussion about this subject has somehow obscured the leading role played by the primary weakness of the venous waii, as shown by Alexander .3 The low-residue diet1,2 does not sufficiently explain why in Western population only some subjects, not particularly constipated,’ are affected by varices early in life. In patients affected by varicosities, the wall of the superficial veins actually shows both a primary deficiency of smooth muscle contractility5 and a greater distensibility’ under moderate pressure load. The excessive distensibility of the wall causes the separation of the valvular cusps’ attachments and, as a consequence, the valvular incompetence. 3,7 We think that the cause of such a weakness is a primary connective tissue defect which may take place if fewer or thinner collagen or elastic fibers (or both) are merged in a richer matrix of proteoglycans, in which they may slip more easily one upon the other. In fact, Svejcarl has found a significant decrease of the collagen content both in actual and in potential varicose veins; on the contrary, he found that the muscle and the hexosamine content increased in varices, in comparison with the controls. But to date, Svejcar’s results’ have not been confirmed by other laboratories.
From the Universita’ Degli Studi di Firenze, Istituto di Clinica (B), Florence, Italy.
Patologia Speciale Medica
798
Downloaded from ang.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 31, 2015
e
Metodologia
799
Materials A nd Methods We have chemically analyzed the connective tissue composition of saphenous veins taken from 32 patients during saphenectomy, and from 34 corpses subjected to necroscopy after sudden usually traumatic, death. These subjects appeared completely free from varicosities of the lower limbs. Two samples of about 10 cm in length were taken from varicose veins, the first from the proximal segment near the junction of the femoral vein, and the other from just below the knee. Only the proximal samples of the control veins were available. Endothelial surface was measured on longitudinally opened samples. The samples were flattened between two glass plates, and the edges of endothelium were delineated with a pencil on a superimposed PVC crystal sheet. The surface was reckoned from the weight of the cutout profile, and the approximate mean circumference of the saphenous vein was calculated by dividing the venous endothelial surface by the mean length of the cutout profile. According to Houck and Jacobs’ method,’ slightly modified, the venous collagen was fractionated in four fractions extractable respectively with NaH2P04 0.5 M at 25° C, NaCI 0.45 M at 4° C, HCI-Na citrate buffer 0.15 M pH 7.3 at 4° C, and NaOH 0.1 N at 98° C for 45 minutes. The collagen was evaluated by multiplying the hydroxyproline content by 7.3 according to Pikkarainen.11 The elastin content was evaluated from the nitrogen content of the insoluble residue after treatment with NaOH 0.1 N at 98° C for 45 minutes. The hydroxyproline were evaluated by Conte’s methodll and the nitrogen by nesslerization, according to Henry.&dquo; The nonscleroprotein and the sugar content were measured on the NaH2P04 0.5 M/25° C extract by the Biuretl2 and Phenol&dquo; methods respectively. Moreover, according to Francis’ and Macmillan’s water method,14,15 we extracted the polymeric collagen from varicose saphenous veins and control veins. Then we tested the stability of the polymeric collagen against depolymerization by the following treatments: (1) thermal denaturation in water at 100° C for 1 hour; (2) cold alkali treatment with NaOH 4 M at 4°C for 6 days; and (3) thermal denaturation in water at 100° C for 1 hour after cold alkali pretreatment. °
R esul ts Table 1 summarizes the results, which are expressed as milligrams per gram of dried or wet tissue, as well as milligrams per square centimeter of endothelial surface. In fact the pressure load of the blood column is exerted on the endothelium itself; and if the endothelium is supported by a smaller amount of collagen and elastin from the outside, the wall will have a clearly lower resistance.
the total collagen found to be significantly decreased in varicose veins, but the elastin content was also. On the other hand, the chemical Not
only
was
Downloaded from ang.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 31, 2015
800 Circumference, Weight,
Values * t
t
§
are
expressed
as mean
TABLE 1 and Connective Tissue Fractions
Varicose and Control Veins
f SE.
Significantly different from control value (P < Significantly different from control value (P < Significantly different from control value (P < Significantly different from control value (P
Daniele Cammelli, M.D.
FLORENCE,
ITALY
A bstract The collagen, elastin, total sugar, and nonscleroprotein content was evaluated in 32 samples of saphenous varicose vein and in 34 controls. A significantly lower collagen and elastin content was found in the varicose samples without correlation with the degree of pathologic broadening. Otherwise the total sugars and the soluble nonscleroproteins were found to be increased in varicose samples. The results are more significant when expressed as milligrams per surface unit of endothelium. Our data support the hypothesis that the decrease in collagen and elastin content is a primary rather than secondary
change. Introduction A widespread concern has been arisen around Burkitt’s epidemiologic works’,’ about the possible implications of a low-fiber diet, peculiar of Western populations, in the pathogenesis of varicose veins of the lower limbs. Discussion about this subject has somehow obscured the leading role played by the primary weakness of the venous waii, as shown by Alexander .3 The low-residue diet1,2 does not sufficiently explain why in Western population only some subjects, not particularly constipated,’ are affected by varices early in life. In patients affected by varicosities, the wall of the superficial veins actually shows both a primary deficiency of smooth muscle contractility5 and a greater distensibility’ under moderate pressure load. The excessive distensibility of the wall causes the separation of the valvular cusps’ attachments and, as a consequence, the valvular incompetence. 3,7 We think that the cause of such a weakness is a primary connective tissue defect which may take place if fewer or thinner collagen or elastic fibers (or both) are merged in a richer matrix of proteoglycans, in which they may slip more easily one upon the other. In fact, Svejcarl has found a significant decrease of the collagen content both in actual and in potential varicose veins; on the contrary, he found that the muscle and the hexosamine content increased in varices, in comparison with the controls. But to date, Svejcar’s results’ have not been confirmed by other laboratories.
From the Universita’ Degli Studi di Firenze, Istituto di Clinica (B), Florence, Italy.
Patologia Speciale Medica
798
Downloaded from ang.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 31, 2015
e
Metodologia
799
Materials A nd Methods We have chemically analyzed the connective tissue composition of saphenous veins taken from 32 patients during saphenectomy, and from 34 corpses subjected to necroscopy after sudden usually traumatic, death. These subjects appeared completely free from varicosities of the lower limbs. Two samples of about 10 cm in length were taken from varicose veins, the first from the proximal segment near the junction of the femoral vein, and the other from just below the knee. Only the proximal samples of the control veins were available. Endothelial surface was measured on longitudinally opened samples. The samples were flattened between two glass plates, and the edges of endothelium were delineated with a pencil on a superimposed PVC crystal sheet. The surface was reckoned from the weight of the cutout profile, and the approximate mean circumference of the saphenous vein was calculated by dividing the venous endothelial surface by the mean length of the cutout profile. According to Houck and Jacobs’ method,’ slightly modified, the venous collagen was fractionated in four fractions extractable respectively with NaH2P04 0.5 M at 25° C, NaCI 0.45 M at 4° C, HCI-Na citrate buffer 0.15 M pH 7.3 at 4° C, and NaOH 0.1 N at 98° C for 45 minutes. The collagen was evaluated by multiplying the hydroxyproline content by 7.3 according to Pikkarainen.11 The elastin content was evaluated from the nitrogen content of the insoluble residue after treatment with NaOH 0.1 N at 98° C for 45 minutes. The hydroxyproline were evaluated by Conte’s methodll and the nitrogen by nesslerization, according to Henry.&dquo; The nonscleroprotein and the sugar content were measured on the NaH2P04 0.5 M/25° C extract by the Biuretl2 and Phenol&dquo; methods respectively. Moreover, according to Francis’ and Macmillan’s water method,14,15 we extracted the polymeric collagen from varicose saphenous veins and control veins. Then we tested the stability of the polymeric collagen against depolymerization by the following treatments: (1) thermal denaturation in water at 100° C for 1 hour; (2) cold alkali treatment with NaOH 4 M at 4°C for 6 days; and (3) thermal denaturation in water at 100° C for 1 hour after cold alkali pretreatment. °
R esul ts Table 1 summarizes the results, which are expressed as milligrams per gram of dried or wet tissue, as well as milligrams per square centimeter of endothelial surface. In fact the pressure load of the blood column is exerted on the endothelium itself; and if the endothelium is supported by a smaller amount of collagen and elastin from the outside, the wall will have a clearly lower resistance.
the total collagen found to be significantly decreased in varicose veins, but the elastin content was also. On the other hand, the chemical Not
only
was
Downloaded from ang.sagepub.com at FLORIDA INTERNATIONAL UNIV on May 31, 2015
800 Circumference, Weight,
Values * t
t
§
are
expressed
as mean
TABLE 1 and Connective Tissue Fractions
Varicose and Control Veins
f SE.
Significantly different from control value (P < Significantly different from control value (P < Significantly different from control value (P < Significantly different from control value (P
