SKIN COLLAGEN AND THICKNESS IN HYPERTHYROIDISM AND MYXOEDEMA

Skin thickness, collagen content and density have been measured in patients with thyrotoxicosis and myxoedema. In hyperthyroidism the skin was of normal thickness but the absolute collagen content and density of collagen were both increased as was the percentage collagen content. In myxoedema both absolute percentage collagen content and density remained normal but the skin thickness was significantly increased and this correlated well with the severity of hypothyroidism and response to treatment.     

Skin thickness and collagen content in progressive systemic sclerosis and localized scleroderma.

Skin biopsies of uniform location and surface area (7 mm diameter) were obtained from the extensor aspect of the forearm of 147 patients with progressive systemic sclerosis (PSS) (107 with diffuse scleroderma, 40 with the CREST syndrome variant) and 58 individuals with normal skin. After careful removal of all subcutaneous fatty tissue, the skin cores were weighed and their water and hydroxyproline content determined. Despite recent claims to the contrary, it was found that there is a marked and highly significant increase in the thickness of the skin during the indurative phase of PSS, and that this is associated with a proportionate increase in total dermal collagen content. A similar degree of thickening was found in the skin of patients with eosinophilic fasciitis and acromegaly. A close correlation was observed between clinical estimation of the degree of skin thickening and the weight of the skin biopsy cores. Change in the weight of skin cores was observed during the course of illness of the patients with PSS and may serve as a useful measurement of alteration in the degree of skin thickening.     

Skin thickness and collagen content in progressive systemic sclerosis and localized scleroderma

Skin biopsies of uniform location and surface area (7 mm diameter) were obtained from the extensor aspect of the forearm of 147 patients with progressive systemic sclerosis (PSS) (107 with diffuse scleroderma, 40 with the CREST syndrome variant) and 58 individuals with normal skin. After careful removal of all subcutaneous fatty tissue, the skin cores were weighed and their water and hydroxyproline content determined. Despite recent claims to the contrary, it was found that there is a marked and highly significant increase in the thickness of the skin during the indurative phase of PSS, and that this is associated with a proportionate increase in total dermal collagen content. A similar degree of thickening was found in the skin of patients with eosinophilic fasciitis and acromegaly. A close correlation was observed between clinical estimation of the degree of skin thickening and the weight of the skin biopsy cores. Change in the weight of skin cores was observed during the course of illness of the patients with PSS and may serve as a useful measurement of alteration in the degree of skin thickening.     

Skin thickness in patients with acromegaly and Cushing''s syndrome and response to treatment

Radiological assessment of skin thickness (ST) was assessed in 22 patients with acromegaly and 17 patients with Cushing's syndrome. The age ranges of the patients studied and the 55 individuals in the control group were comparable. The skin thickness in males was significantly greater than in females (P less than 0.01). Mean skin thickness in patients with acromegaly and Cushing's syndrome was significantly greater and less respectively than the mean skin thickness of the normal controls (P less than 0.02). Following successful treatment of acromegaly (growth hormone less than 5 micrograms/l) there was a significant reduction in skin thickness (P less than 0.02 males: P less than 0.01 females). The skin thickness declined at approximately 0.3 mm/year for the first two years and more slowly thereafter. A highly significant correlation was observed between the logarithm of the pre and post treatment plasma GH concentrations and ST values. With one exception, all patients with growth hormone (GH) levels greater than 5 micrograms/l had ST values above the normal range. At an average of 4.5 years after successful treatment of Cushing's syndrome the average increase in ST was 0.23 mm (P less than 0.01). It is concluded that the measurement of skin thickness is a useful screening test for both acromegaly and Cushing's syndrome and provides an objective assessment of the clinical response to treatment.     

Collagen Fiber Formation in Repair Tissue: Development of Strength and Toughness

Dermal repair tissue shows a progressive increase in collagen content which may be related to the wound tensile strength. Wound strength and extensibility are lower than those found in normal skin. In animals, wounds closed by metal clips are chosen as a model to study the proliferative and remodeling phases of healing from a mechanical and morphological point of view. During the proliferative phase the low wound strength is associated with formation of collagen fibers of small diameter, later, (days 28–45) an acute change appears corresponding to the remodeling phase, with 1) increased collagen fiber diameters observed by scanning electron microscopy and light microscopy, and 2) increased tensile strength and toughness. By 180 days, wound strength and collagen fiber morphology were close to that observed in the normal skin. These observations show a direct relationship between collagen fiber diameter and tensile strength. In addition, packing density of collagen fibrils (determined by the birefringence retardation per unit thickness under polarized light) was unchanged until day 90, although collagen fiber diameters increased during this time.     

Cutaneous extensibility in health and disease.

The results are recorded of a number of studies performed over the last few years using a simple and reproducible method for investigating the extensibility of intact skin. A major advantage of this method lies in the fact that it causes the patient no discomfort and leaves his skin without blemish. We have found abnormal behaviour of skin in response to applied stress in the heritable connective tissue disorders: Ehlers-Danlos Syndrome, cutis laxa, and pseudoxanthoma elasticum, and in the acquired disorders of acromegaly, hypopituitarism and scleroderma. An abnormal elastic modulus, however, was found only in pseudoxanthoma elasticum and the growth-hormone disorders.     

Age and sex as predictors of biochemical activity in acromegaly: analysis of 1485 patients from the German Acromegaly Register

Objective  We evaluated the German Acromegaly Register for clinical variables associated with the initial biochemical activity of patients with acromegaly.
Design  Retrospective analysis of data in the registry.
Patients   A total of 1485 patients with acromegaly (males 45·6%, females 54·4%) were treated in 42 German endocrine centres until November 2005. Linear regression models were used to estimate the influence of various parameters on biochemical activity.
Results  Male patients with acromegaly were significantly younger at the time of diagnosis than female patients (41 vs. 47 years, P  < 0·0001) and had significantly higher random GH levels than females (21 vs. 14 ng/ml, P  < 0·005) and IGF-1 levels (773 vs. 679 ng/ml, P  < 0·0001), respectively. Age at initial presentation turned out to be the most important independent risk factor associated with random GH levels, oral glucose tolerance test-suppressed GH levels, IGF-1 levels, body mass index (BMI), tumour size and prevalence of hypopituitarism. Sex was an independent risk factor for IGF-1 levels, BMI and prevalence of hypopituitarism. Tumour size was an independent risk factor for both GH and IGF-1 levels.
Conclusions  In summary, initial biochemical activity of acromegaly is influenced by patient's age and to a lesser degree by patient's sex. Male patients are on an average 6 years younger than females.     

Decreased high density lipoprotein cholesterol in hypopituitarism.

Serum triglyceride, cholesterol, and high density lipoprotein cholesterol (HDL-C) levels were measured in 10 men and 3 women with hypopituitarism. The mean total cholesterol and triglyceride levels were significantly increased but were within the range of controls. The mean HDL-C concentration and the HDL-C to total cholesterol ratio were significantly decreased. Similar findings were present in a patient with isolated GH deficiency. Two men with Kallman's syndrome and 3 patients with active acromegaly had values that were either within or just below the normal range. Replacement therapy with thyroid hormone and prednisone resulted in a normalization of HDL-C concentrations in four of the five patients studied. This improvement suggests a role for thyroid hormone and/or glucocorticoids in the maintenance of normal HDL-C concentrations. These observations also suggest that the distribution of plasma lipoprotein fractions is dependent in part, either directly or indirectly, on pituitary hormones.     

Urinary growth hormone (GH) measurements are useful for evaluating endogenous GH secretion

Daily (24-h) urinary GH excretion was measured using a highly sensitive sandwich enzyme immunoassay in 10 normal adults, 6 patients with hypopituitarism, 25 normal but short children who had normal plasma GH responses (peak plasma GH level, greater than 10 micrograms/L) to provocative tests, and 8 patients with acromegaly. The mean urinary GH values in the normal adults, patients with acromegaly, and patients with hypopituitarism were 13.8 +/- 4.0 (+/- SE) and 431.1 +/- 149.1 ng/g creatinine (Cr) (1.56 +/- 0.45 and 48.77 +/- 16.87 ng/mmol Cr) and undetectable, respectively; these mean values were significantly different from each other. In the normal but short children the urinary values ranged from undetectable to 55.8 ng/g Cr (6.31 ng/mmol Cr). All of the normal but short children and 4 patients with hypopituitarism participated in a 24-h endogenous GH secretion study. The urinary GH values correlated significantly with the mean 24-h plasma GH concentrations as an index of endogenous GH secretion (r = 0.81; P less than 0.001) and plasma somatomedin-C levels (r = 0.67; P less than 0.001), respectively. In 6 patients with acromegaly whose plasma GH levels were constant throughout a 4-h period, the urinary GH values also significantly correlated with the mean plasma GH levels (r = 0.95; P less than 0.01). These data indicate that urinary GH measurements reflect endogenous GH secretion and that measurement of urinary GH excretion is a useful, simple, and practical method for evaluating endogenous GH secretion.     

Reduced strength of skin in Ehlers Danlos syndrome, type III

The biochemical properties, ratio collagen type I/type III and the pattern of reducible collagen crosslinks were studied in skin biopsy samples from 10 patients with Ehlers Danlos syndrome type III (ED III) and 10 age- and sex-matched controls. The ED III patients had marked reductions in skin strength and stiffness (42% and 22%, respectively). The ultimate extensibility of the skin, however, was not different from that of the controls. Consequently, a certain load applied to the skin of these patients results in greater deformation than in that of the controls, due to reduced stiffness. The bursting limit is no different from that of the controls. Thus the skin in the ED III patients is not hyperextensible, it merely has reduced strength and stiffness. The reduction in strength could not be explained by differences in skin thickness or collagen content. Skin thickness, collagen content and ratio collagen type I/type III were the same as in the controls, as also was the pattern of reducible collagen crosslinks. These alterations in the mechanical properties of the skin of patients with ED III may be attributable to the molecular structure of the mature collagen or the arrangement of the collagen fibres.     

REDUCTION OF SKIN COLLAGEN WITH INCREASED SKIN THICKNESS IN POSTMENOPAUSAL WOMEN WITH RHEUMATOID ARTHRITIS

Thirty postmenopausal women with rheumatoid disease were investigatedwith skin biopsies and radiological measurements of skin thickness.When compared with menopausal-age-matched controls, the rheumatoidpatients had significantly reduced skin collagen content andincreased skin thickness. KEY WORDS: Skin, Rheumatoid arthritis, Postmenopausal     

LONG-TERM EFFECTS OF MEGAVOLTAGE RADIOTHERAPY IN ACROMEGALY

The progress of 41 Chinese patients with acromegaly treated with megavoltage radiotherapy was reviewed after a mean follow-up of 4.5 (one-ten) years. Nine received prior surgery. Radiotherapy was delivered by a 3-field technique to a total of 4000–5000 cGy in 25 fractions. By life table analysis successful treatment of growth hormone (GH) hypersecretion, as defined by a mean GH concentration of 10 mu/L, could be expected in 6, 11, 26, 64 and 67% of the patients after one, two, five, eight and ten years respectively. Median intervals before achieving a mean GH level of 10 mu/L were 6.6 and 8.6 years following radiotherapy with the higher (4500–5000 cGy) and lower (4000 cGy) doses respectively, suggesting a tendency towards earlier response following radiotherapy with the higher dose. The prevalence of acquired hypopituitarism in patients followed up for over five years was 40% for gonadotrophins, 30% for TSH and 20% for ACTH deficiency respectively. In the majority of patients, acquired hypopituitarism was not apparent within five years after radiotherapy. No mortality or major side effects were noted following radiotherapy. In 34 patients on long-term bromocriptine treatment, mean GH concentrations were normalised in 26.5% of patients. We conclude that with judicious selection of patients and use of adjunctive medical therapy, megavoltage radiotherapy remains a safe and satisfactory form of treatment for acromegaly especially if expert transphenoidal surgery is not readily available.     

Investigation on the effects of experimental STZ-induced diabetic rat model on basal membrane structures and gap junctions of skin

This study was designed to determine the impairment of the skin structure in experimentally-induced diabetes with injection of streptozotocin (STZ). Experimental groups consisted of controls (group 1, N?=?10) and diabetes groups (group 2, N?=?10). Dorsal skin was removed for routine histological tissue procedures. Hematoxylene and Eosin (HE), Masson’s Trichrome and Periodic Acid Schiff (PAS) stainings, immunohistochemical connexin 43 (Cx43) and type IV collagen stainings were applied. Morphometry of epidermal thickness were also determined. Group 2 revealed decrease in epidermal thickness with disintegration of epithelium and decrease of dermal collagen fibers. Stratum spinosum were morphologically abnormal for group 2. Measurements of epidermal thickness revealed statistically significant decrease (P?=?0.000). PAS staining for group 2 revealed disruption of the basement membrane. Epithelial scar formation, deterioration of transformation in the polyhedral cells, degradation of epidermis and decrease in PAS staining for vascular structures were observed, whereas the reticular dermis and hair follicles were normal. Collagen fiber density in group 2 were found to be prominently decreased in dermis with Masson’s Trichrome staining. Evident decrease in immunostaining of Cx43 and type IV collagen were also shown in diabetic group in comparison to the controls. In conclusion, diabetes not only induced impairment of the epidermal integrity and deterioration in the epidermis via loss of gap junctions (the most prominent cellular junctional complex), but also caused dramatically negative impact on the dermal collagen content, and integrity of the basement membrane.     

Inflammatory cardiovascular risk markers in women with hypopituitarism.

Patients with hypopituitarism have increased cardiovascular mortality. A high prevalence of conventional cardiovascular risk factors, including obesity, central fat distribution, insulin resistance, and dyslipidemia, have been described in these patients. The inflammatory markers C-reactive protein (CRP) and IL-6 are predictors of cardiovascular events, and high levels of CRP have been reported in men with hypopituitarism and GH deficiency. However, little is known about inflammatory cardiovascular risk markers in women with hypopituitarism. We therefore investigated whether inflammatory and traditional cardiovascular risk markers are elevated in women with hypopituitarism. Fifty-three women with hypopituitarism and 111 healthy control women were included in this cross-sectional study. Morning blood samples were drawn after an overnight fast. Serum was assayed for CRP, IL-6, glucose, insulin, IGF-I, triglycerides, total cholesterol, low density lipoprotein cholesterol, high density lipoprotein (HDL) cholesterol, lipoprotein(a), E2, total testosterone (total T) and free testosterone (free T), and dehydroepiandrosterone sulfate. IL-6 and CRP levels were higher in women with hypopituitarism than in healthy controls (P < 0.0001 for comparison between groups). In a multivariate model, CRP levels depended on hypopituitarism, body mass index (BMI), and estrogen use. There was an interaction between the effect of BMI and hypopituitarism on CRP levels, such that the importance of hypopituitarism in determining CRP levels disappeared at high BMIs. In a similar multivariate model, IL-6 levels depended on hypopituitarism and BMI. Total cholesterol, the total to HDL cholesterol ratio, and triglycerides were higher in hypopituitary patients, but only triglycerides and the total to HDL cholesterol ratio depended on hypopituitarism when controlling for BMI. There was no significant difference in lipoprotein(a) levels between hypopituitary women and control subjects. However, when controlling for estrogen use, lipoprotein(a) levels showed a trend toward being lower in the hypopituitary group (P = 0.075). In patients with hypopituitarism, CRP correlated negatively with IGF-I (r = -0.35; P = 0.010), total T (r = -0.42; P = 0.0020), and free T (r = -0.30; P = 0.031). Similarly, IL-6 correlated negatively with total T (r = -0.39; P = 0.0040) and androstenedione (r = -0.27; P = 0.048) in hypopituitary patients. In conclusion, hypopituitary women have increased levels of IL-6 and CRP, both of which are inflammatory markers of atherosclerosis. GH deficiency and androgen deficiency may contribute to these findings. Chronic inflammation may contribute to the high cardiovascular risk seen in this population.     

Age changes in collagen characteristics of bone and skin of a short-lived species of reptile.

Decalcified bone collagen of older male garden lizards, Calotes versicolor, was less susceptible to digestion by collagenase from Clostridium histolyticum than that from younger individuals. In aged skin the percentage solubility and the soluble/insoluble collagen ratio decreased, with a concomitant rise in insoluble and total collagen. Collagen/unit area increased with advancing age in both dorsal and ventral skin. These results from a non-mammalian poikilothermic vertebrate provide additional evidence in favour of the cross-linkage theory of ageing and suggest a common pattern of collagen ageing in vertebrates.     

Morphometric analysis of dermal collagen fibers in normal human skin as a function of age

A quantitative study of dermal collagen as a function of age was carried out by computerized digital image analysis. Fast Green-Syrius Red stained sections were obtained of skin biopsies taken from the upper inner arm of 33 healthy women and 38 healthy men. The Leitz texture Analysis System (Leitz-TAS) and mathematical morphology (Serra, 1982) were used for the evaluation of the data. Collagen was studied in the superficial dermis and also in the reticular dermis using the same program. There were significant correlations, firstly between the percentage of collagen measured by the morphometric method and the concentration of collagen analysed biochemically (microg/mm(2) of tissue section) (r = 0.79, p < 0.001) and secondly between the decreased concentration of collagen and age (r = 0.58, p < 0.05). The morphometrical measurements have shown that the relative percentage of collagen bundles (surface of collagen fibers as a function of the dermal area analyzed) was 93.35% in the superficial dermis and 89.2% in the reticular dermis. Although this value is higher than the chemically determined ratio of collagen to other proteins (over 70%), this may be due to the relatively uniform distribution pattern of (type I and III) collagen through the dermis covering most other components of the skin. As the collagen fiber density per unit dermal surface did not change with age, the decrease in collagen content of the skin may be ascribed to the loss of about 6% of dermal mass per decade (Branchet, 1990), although large individual variations exist. The histogram of the diameter distribution of collagen fiber bundles of the reticular dermis showed thinner diameters in persons between 20 and 40 years of age than in older persons. The histogram of the distribution of interfiber spaces did not show any variation with age in the superficial dermis, while in the reticular dermis there was a predominance of smaller interspaces in persons older than 50 years.     

Supranormal stimulation of deoxyribonucleic acid synthesis in FRTL5 cells by serum from patients with untreated acromegaly

Insulin-like growth factor I (IGF-I) is one of a number of mitogenic factors in the serum of animals and humans. We demonstrated previously that IGF-I is a potent mitogen for FRTL5 cells, a line of rat thyroid follicular cells. In this study, we assessed the relevance of this finding with respect to the levels of IGF-I found in human serum by comparing the effects of normal serum and serum from patients with untreated acromegaly or hypopituitarism on DNA synthesis in quiescent FRTL5 cells. As expected, when added to cells maintained in Coon's modified Ham's F-12 medium containing 0.1% BSA, but devoid of insulin, transferrin, TSH, or calf serum, normal serum produced a dose-dependent stimulation of [3H]thymidine incorporation into DNA. A similar, but more marked, effect was produced by the addition of serum from patients with untreated acromegaly. In multiple experiments, a standard concentration (0.5%) of acromegaly serum was more stimulatory to DNA synthesis than was normal serum. In a single experiment designed to eliminate interassay variation and define the relationship between the ability of serum to stimulate DNA synthesis and its IGF-I concentration, studies were performed with 0.5% concentrations of serum from 9 normal subjects, 15 patients with untreated acromegaly, and 3 patients with panhypopituitarism. On the average, [3H]thymidine incorporation in the presence of serum from patients with acromegaly was approximately 3 times, and that in the presence of serum from patients with hypopituitarism only one fourth, that in the presence of serum from normal subjects; there was no overlap of individual values in the three groups. For the entire study group, we found a highly significant correlation (r = 0.86) between the serum IGF-I concentration and the ability of that serum to stimulate thymidine incorporation into the DNA of FRTL5 cells. The stimulatory effects of serum from both normal and acromegalic subjects were decreased or abolished by the addition of a monoclonal antibody against IGF-I. In hypophysectomized rats, GH increases the thyroid to body weight ratio and enhances the effect of TSH to promote thyroid growth. Further, an inordinate frequency of nontoxic goiter in patients with acromegaly has been reported. Taken together with these observations, our findings suggest that the effect of IGF-I to promote thyroid cell growth in vitro has a counterpart in the living animal or patient.     

Cerebrovascular disease in patients with pituitary tumors.

Several studies have shown that patients with acromegaly have increased mortality rates for cardiovascular disease and cerebrovascular disease (CVD). Similar associations have also been seen for patients with hypopituitarism or with non-functional pituitary adenomas. This review summarizes these data and discusses the relative importance of different risk factors for cardiovascular, especially CVD, mortality among patients with acromegaly or non-functional pituitary adenomas, and for those with hypopituitarism as a result of other causes.     

ASSESSMENT OF BODY COMPOSITION IN NORMAL AND OBESE SUBJECTS

SUMMARY Multiple anthropometric measurements, which included those of weight, height, skinfold thickness, bone diameters and limb circumferences, together with estimations of creatinine excretion, were performed on 52 male and 42 female healthy subjects, both obese and of normal weight. Fat mass was estimated from two equations, which had been derived by previous workers from measurements of body density, and combined total body water content and body density. One was based on weight and skeletal measurements, and the other on the iliac crest circumference and triceps skinfold thickness. It was shown that there was close agreement between these two estimates, even in very obese subjects, thus extending the observations made by the original authors. When the mean of these two values was used as the reference value for fat mass, it was found that the latter could be simply predicted in both sexes from weight/height² and percentage ideal weight calculations and in males from iliac crest circumference. The error of prediction was less than 6·8 kg. (twice the S.D.). Prediction was better (error less than 5·2 kg.) in both sexes using both weight/height² and the iliac crest circumference. Skinfold thicknesses were of less value in predicting fat mass. These conclusions only apply to Western populations of this type of body build, in whom fat is almost exclusively responsible for variations in bulk. In interracial studies, skin fold measurements may give a better estimate of relative obesity. With creatinine excretion as our index of muscle mass, we found that no body measurement was of value in estimating muscularity. The best parameter was fat-free weight, but this was of poor value, especially in obese males. It emphasizes that muscle forms a very variable proportion of fat-free weight. To obtain a reliable estimate of muscularity in population studies it appears essential to estimate creatinine excretion.     

Gamma knife radiosurgery for acromegaly--long-term experience

OBJECTIVE: The Leksell gamma knife (LGK) is one of the treatment options for pituitary adenomas. We report on our long-term experience treating acromegaly using LGK. DESIGN: Since 1993 we have followed 96 acromegaly patients through periods of from 12 to 120 months. The mean follow-up period was 53.7 +/- 26.8 months. Seventy-two patients were treated with neurosurgery prior to LGK; for 24 LGK was the primary treatment. Thirteen patients were irradiated twice, due to persistent activity of the adenoma or its residue. Pituitary functions were tested at 6-month intervals, post-irradiation. The target tumour volume for radiosurgery was between 93.3 and 12 700 mm3 (median 1350 mm3). RESULTS: Fifty per cent of the patients achieved mean GH < 2.5 microg/l within 42 months, normalized their IGF-I within 54 months, and achieved GH suppression in the oral glucose tolerance test (oGTT) < 1 microg/l with normal IGF-I within 66 months. LGK effectiveness was dependent on initial adenoma hormonal activity (GH and IGF-I serum levels), not on the size of the adenoma. Patients with primary neurosurgery followed by LGK irradiation had better outcomes than those with LGK alone. Irradiation arrested all adenoma growth, causing tumour shrinkage in 62.3% of patients. Twenty-six developed hypopituitarism when irradiated by 15 Gy (or more) on functional peritumoral pituitary tissue. No hypopituitarism appeared using lower doses. CONCLUSIONS: In acromegaly, LGK is a useful adjunct to primary neurosurgery when treating post-surgical residues because it can limit the duration of medical therapy. It can be used as a primary therapy when neurosurgery is not possible.