Skin morphological changes in growth hormone deficiency and acromegaly

Cutaneous findings in patients with acromegaly and its relationship with concomitant endocrinopathies

OBJECTIVES

Skin changes in acromegaly are often the first sign of the disease. The aim of this study was to describe the cutaneous findings in patients with acromegaly. In addition, a secondary aim was to investigate the possible association of these findings with remission status and concomitant endocrinopathies.

DESIGN, PATIENTS, AND MEASUREMENTS

In this prospective multicenter study, 278 patients over the age of 18 years with acromegaly who were followed up in 14 different tertiary healthcare institutions were included. These patients, who were followed up by the Endocrinology Department, were then referred to a dermatologist for dermatological examination. The frequency of skin lesions was investigated by detailed dermatologic examination. Dermatological diagnosis is reached by clinical, dermatological and/or dermoscopic examination, and rarely skin punch biopsy examinations in suspicious cases. The possible association of the skin findings between remitted and nonremitted patients and with concomitant endocrinopathies were evaluated.

RESULTS

The most common skin findings in patients with acromegaly in our study were skin tags (52.5%), cherry angiomas (47.4%), seborrhoea (37%), varicose veins (33%), acneiform lesions (28.8%), hyperhidrosis (26.9%) and hypertrichosis (18.3%). Hypertrichosis was significantly more prevalent in patients nonremitted (p: .001), while xerosis cutis was significantly more prevalent in patients remitted (p: .001). The frequency of diabetes mellitus and hypothyroidism was significantly higher in patients with varicose veins and seborrhoeic keratosis than those without. Additionally, the coexistence of hypothyroidism, hyperthyroidism and galactorrhea was significantly higher in patients with Cherry angioma than in those without Cherry angioma (p-values: .024, .034 and .027, respectively). The frequency of hypogonadism in those with xerosis cutis was significantly higher than in those without (p: .035).

CONCLUSIONS

Cutaneous androgenization findings such as skin tag, seborrhoea, acne and acanthosis nigricans are common in patients with acromegaly. Clinicians should be aware that skin findings associated with insulin resistance may develop in these patients. It can be said that the remission state in acromegaly has no curative effect on cutaneous findings. Only patients in remission were less likely to have hypertrichosis. This may allow earlier review of the follow-up and treatment of acromegaly patients presenting with complaints of hypertrichosis. Additionally, it can be said that patients with skin findings such as cherry angioma may be predisposed to a second endocrinopathy, especially hypothyroidism. Including dermatology in a multidisciplinary perspective in acromegaly patient management would be beneficial to detect cutaneous findings earlier.

Skin assessment in congenital untreated isolated GH deficiency

PURPOSE

The separation between the inside and outside through the skin was fundamental for the evolution of prevertebrates, which grow through extrapituitary circuits, to vertebrates, which grow through the somatotrophic axis, namely pituitary growth hormone (GH). and circulating IGF1.Individuals with untreated isolated growth hormone (GH) deficiency (IGHD) due to a mutation in the GH-releasing hormone receptor (GHRH) gene, residing in Itabaianinha, Brazil, are vulnerable to skin cancer and have reduced sweating. However other aspects of their skin physiology are still unknown. Our objectives were to evaluate the number of skin cancers, skin aging, and functional aspects of the skin in this IGHD cohort.

METHODS

Twenty-six IGHD individuals and 26 controls matched by age, sex, ethnicity, and occupation were submitted to a biochemical, dermatological and a functional skin assessment by the Multi Probe Adapter Cutometer® MPA 580.

RESULTS

There was no difference in the number of skin cancers and in the degrees of photodamage between the groups. The melanin content in the forearm was similar between the groups but was lower in the buttocks (p = 0.005), as well as skin resistance (p < 0.0001) and elasticity (p = 0.003), lower in the IGHD. There was no difference in hydration and sebum content between the two groups.

CONCLUSION

IGHD is apparently associated with a neutral profile in terms of skin cancer and photodamage, with similar melanin on the forearm and lower buttocks, lower skin resistance and elasticity, with hydration and sebum similar to controls.

Development of nano-liposomal human growth hormone as a topical formulation for preventing uvb-induced skin damage

Due to its involvement in skin maintenance and repair, topical administration of recombinant human growth hormone (rhGH) is an interesting strategy for therapeutic purposes. We have formulated and characterized a topical rhGH-loaded liposomal formulation (rhGH-Lip) and evaluated its safety, biological activity, and preventive role against UVB-induced skin damage. The rhGH-Lip had an average size and zeta potential of 63 nm and -33 mV, respectively, with 70 % encapsulation efficiency. The formulation was stable at 4 °C for at least one year. The SDS-PAGE and circular dichroism results showed no structural alterations in rhGH upon encapsulation. In vitro, studies in HaCaT, HFFF-2, and Ba/F3-rhGHR cell lines confirmed the safety and biological activity of rhGH-Lip. Franz diffusion cell study showed increased rhGH skin permeation compared to free rhGH. Animal studies in nude mice showed that liposomal rhGH prevented UVB-induced epidermal hyperplasia, angiogenesis, wrinkle formation, and collagen loss, as well as improving skin moisture. The results of this study show that rhGH-Lip is a stable, safe, and effective skin delivery system and has potential as an anti-wrinkle formulation for topical application. This study also provides a new method for the topical delivery of proteins and merits further investigation.

GH and IGF-1 in skin interstitial fluid and blood are associated with heat loss responses in exercising young adults

PURPOSE

Sweat glands and cutaneous vessels possess growth hormone (GH) and insulin-like growth factor 1 (IGF-1) receptors. Here, we assessed if exercise increases GH and IGF-1 in skin interstitial fluid, and whether baseline and exercise-induced increases in GH and IGF-1 concentrations in skin interstitial fluid/blood are associated with heat loss responses of sweating and cutaneous vasodilation.

METHODS

Sixteen young adults (7 women) performed a 50-min moderate-intensity exercise bout (50% VO2peak) during which skin dialysate and blood samples were collected. In a sub-study (n = 7, 4 women), we administered varying concentrations of GH (0.025-4000 ng/mL) and IGF-1 (0.000256-100 µg/mL) into skin interstitial fluid via intradermal microdialysis. Sweat rate (ventilated capsule) and cutaneous vascular conductance (CVC) were measured continuously for both studies.

RESULTS

Exercise increased sweating and CVC (both P < 0.001), paralleled by increases of serum GH and skin dialysate GH and IGF-1 (all P ≤ 0.041) without changes in serum IGF-1. Sweating was positively correlated with baseline dialysate and serum GH levels, as well as exercise-induced increases in serum GH and IGF-1 (all P ≤ 0.044). Increases in CVC were not correlated with any GH and IGF-1 variables. Exogenous administration of GH and IGF-1 did not modulate resting sweat rate and CVC.

CONCLUSION

(1) Exercise increases GH and IGF-1 levels in the skin interstitial fluid, (2) exercise-induced sweating is associated with baseline GH in skin interstitial fluid and blood, as well as exercise-induced increases in blood GH and IGF-1, and (3) cutaneous vasodilation during exercise is not associated with GH and IGF-1 in skin interstitial fluid and blood.

Skin manifestations and submacroscopical features of acromegaly: A case-control study using dermoscopy and high-frequency ultrasound

BACKGROUND

Although the cutaneous involvement of acromegaly has been recognized, the submacroscopical skin changes and the extent of skin thickening of patients remain unclear.

OBJECTIVES

This study aimed at investigating the clinical cutaneous manifestations, dermoscopic features, and skin thickness revealed by high-frequency ultrasound (HFUS) of acromegalic patients.

METHODS

A case-control observational study was conducted. Patients with acromegaly and controls were prospectively included and received thorough cutaneous examinations to compare the macroscopical and dermoscopic features. The skin thickness measured by HFUS and its correlation with clinical data were also assessed.

RESULTS

Thirty-seven and 26 patients from acromegalic and control group were included, respectively. Clinical skin manifestations were recorded in detail. Under dermoscopy, red structureless area (91.9% vs. 65.4%, p = 0.021), perifollicular orange halo (78.4% vs. 26.9%, p = 0.005), and follicular plug (70.3% vs. 3.9%, p = 0.001) in the facial area, and perifollicular pigmentation (91.9% vs. 23.1%), broom-head hairs (83.8% vs. 3.9%), honeycomb-like pigmentation (97.3% vs. 38.46%), widened dermatoglyphics (81.1% vs. 3.9%) at the extremities (p < 0.001) were more prevalent in acromegaly. The mean skin thickness was 4.10 ± 0.48 mm for acromegaly, and 3.55 ± 0.52 mm for controls (p < 0.001) but no correlation with disease duration, adenoma size, and hormone level was found in acromegaly.

CONCLUSIONS

Submacroscopical skin changes under dermoscopy and skin thickness increase assessed by HFUS can provide clinicians with subtle evidences for early detection of acromegaly and objective parameters for accurate assessment of its skin involvement.

Exocrine gland structure-function relationships

Fluid secretion by exocrine glandular organs is essential to the survival of mammals. Each glandular unit within the body is uniquely organized to carry out its own specific functions, with failure to establish these specialized structures resulting in impaired organ function. Here, we review glandular organs in terms of shared and divergent architecture. We first describe the structural organization of the diverse glandular secretory units (the end-pieces) and their fluid transporting systems (the ducts) within the mammalian system, focusing on how tissue architecture corresponds to functional output. We then highlight how defects in development of end-piece and ductal architecture impacts secretory function. Finally, we discuss how knowledge of exocrine gland structure-function relationships can be applied to the development of new diagnostics, regenerative approaches and tissue regeneration.

GHRH expression plasmid improves osteoporosis and skin damage in aged mice

The hormone secretion of GHRH-GH-IGF-1 axis in animals was decreased as aging. These hormones play an important role in maintaining bone mass and bone structure, and also affect the normal structure and function of the skin. We used plasmid-based technology to deliver growth hormone releasing hormone (GHRH) to elderly mice. In the current study, 80 and 120 μg/kg pVAX-GHRH plasmid expression plasmid were injected into old mice, the serum GHRH and insulin-like growth factor-1(IGF-1) content were increased within three weeks (P < 0.05). In the groups of 80 and 120 μg/kg plasmid, the content of procollagen type I N-terminal pro-peptide (PINP) in the serum was increased(P < 0.05), and the content of C-terminal telopeptides of type I collagen (CTX-1) in the serum was reduced significantly (P < 0.05). Furthermore, the expression of osteoprotegerin (OPG) and osteocalcin (OCN) in the femur also was increased(P < 0.05). The bone mineral density(BMD)、trabecular bone volume (BV/TV) and trabecular number(Tb.N) of mouse femur were increased significantly (P < 0.05) and trabecular separation(Tb.Sp) was decreased(P < 0.05). There were more trabecular bones in the bone marrow cavity and the trabecular bones are thicker in the groups of 80 and 120 μg/kg plasmid relative to control. The superoxide dismutase (SOD) content in the skin was increased(P < 0.05), and the malondialdehyde (MDA) content was reduced significantly (P < 0.05). Meanwhile, the skin moisture content also increased significantly(P < 0.05). Moreover, the expression of matrix metalloproteinase 3(MMP3) and matrix metalloproteinase 9(MMP9) was decreased in the skin(P < 0.05). The thickness of the dermis and epidermis of the skin had increased significantly(P < 0.05). Skin structure is more dense and complete in the two groups. These results indicate that 80 and 120 μg/kg plasmid-mediated GHRH supplementation can improve osteoporosis and skin aging in aged mice.

Changes in anterior segment parameters and presence of dry eye disease in patients with acromegaly: A Sirius topography study combined with meibography

PURPOSE

To investigate anterior segment parameters (ASPs) and dry eye disease (DED), including the status of the meibomian glands, in patients with acromegaly.

METHODS

In this cross-sectional, comparative study, 36 acromegaly patients and 40 healthy sex- and age-matched controls were included. Participants received a comprehensive ophthalmological examination, including intraocular pressure measurements with Goldmann applanation tonometry (IOP_GAT) and central corneal thickness corrected intraocular pressure (IOP_CCT) measurements, and were evaluated for ASPs and DED. For ASPs, white-to-white (WTW), apical (ACT) and thinnest corneal thickness (TCT), corneal volume (CV), keratometry readings (K₁, K₂, and K_mean), anterior chamber depth (ACD) and volume (ACV), and iridocorneal angle (ICA) were obtained via Sirius topography. DED was assessed with Schirmer's test, tear breakup time (TBUT), and Ocular Surface Disease Index (OSDI) scores. Meibography scores (MSs) were obtained with the Sirius topography device.

RESULTS

Patients had higher mean IOP_GAT (P = .006), IOP_CCT (P = .01), ACT (P = .024), and TCT (P = .005) but narrower ICA (P = .014) than controls. Although Schirmer's test did not differ between the groups (P = .442), patients had higher OSDI (P < .001), higher MS (P = .001), and shorter TBUT (P = .002).

CONCLUSION

Patients with acromegaly have greater IOP, greater corneal thickness, but narrower ICA than healthy individuals, as well as DED with increased MSs, which suggests meibomian gland dysfunction.

Neuroendocrinology and neurobiology of sebaceous glands

The nervous system communicates with peripheral tissues through nerve fibres and the systemic release of hypothalamic and pituitary neurohormones. Communication between the nervous system and the largest human organ, skin, has traditionally received little attention. In particular, the neuro-regulation of sebaceous glands (SGs), a major skin appendage, is rarely considered. Yet, it is clear that the SG is under stringent pituitary control, and forms a fascinating, clinically relevant peripheral target organ in which to study the neuroendocrine and neural regulation of epithelia. Sebum, the major secretory product of the SG, is composed of a complex mixture of lipids resulting from the holocrine secretion of specialised epithelial cells (sebocytes). It is indicative of a role of the neuroendocrine system in SG function that excess circulating levels of growth hormone, thyroxine or prolactin result in increased sebum production (seborrhoea). Conversely, growth hormone deficiency, hypothyroidism, and adrenal insufficiency result in reduced sebum production and dry skin. Furthermore, the androgen sensitivity of SGs appears to be under neuroendocrine control, as hypophysectomy (removal of the pituitary) renders SGs largely insensitive to stimulation by testosterone, which is crucial for maintaining SG homeostasis. However, several neurohormones, such as adrenocorticotropic hormone and α-melanocyte-stimulating hormone, can stimulate sebum production independently of either the testes or the adrenal glands, further underscoring the importance of neuroendocrine control in SG biology. Moreover, sebocytes synthesise several neurohormones and express their receptors, suggestive of the presence of neuro-autocrine mechanisms of sebocyte modulation. Aside from the neuroendocrine system, it is conceivable that secretion of neuropeptides and neurotransmitters from cutaneous nerve endings may also act on sebocytes or their progenitors, given that the skin is richly innervated. However, to date, the neural controls of SG development and function remain poorly investigated and incompletely understood. Botulinum toxin-mediated or facial paresis-associated reduction of human sebum secretion suggests that cutaneous nerve-derived substances modulate lipid and inflammatory cytokine synthesis by sebocytes, possibly implicating the nervous system in acne pathogenesis. Additionally, evidence suggests that cutaneous denervation in mice alters the expression of key regulators of SG homeostasis. In this review, we examine the current evidence regarding neuroendocrine and neurobiological regulation of human SG function in physiology and pathology. We further call attention to this line of research as an instructive model for probing and therapeutically manipulating the mechanistic links between the nervous system and mammalian skin.

Impact of the Transfersome Delivered Human Growth Hormone on the Dermal Fibroblast Cells

Objective:

Transfersomes are highly flexible vesicles that are capable of passing through pores smaller than their own sizes due to their elastochemical characteristics, and thus play a key role in drug delivery to the skin.

Methods:

In this study, we used transdermal delivery of growth hormone-encapsulated transferosomes (F1 and F2) as antiaging strategy, with the resulting effects being subsequently evaluated. The size, distribution and zeta potential of the particles, together with the in vitro skin permeation and biological activity of the growth hormone loaded onto the transfersomes were measured.

Results:

The data demonstrated that treatment of fibroblasts with encapsulated hGH increased cell migration, proliferation and collagen I and III gene expression. According to our results, the maximum amount of growth hormone that passes through the skin during a 24 h time period was 489.54 and 248.46 ng/cm3, for the F1 and F2 transfersomes, respectively. In addition, it was determined that F1 formula as the more efficient carrier, showed no toxicity against cells. With regard to fibroblasts, as one of the most important cells involved in collagen synthesis, skin aging and wound healing, concentrations of growth hormone encapsulated in transferosomes that had an effect on fibroblast growth and division, were determined. The results demonstrated that effective concentrations of the encapsulated growth hormone increased the expression of collagen I and collagen III genes.

Conclusion:

Furthermore, analyzing the rate of fibroblast cell migration showed that migration increased significantly at 700 ng/ml growth hormone concentrations, as compared to that of the control.

Sweat and vitamin D status in congenital, lifetime, untreated GH deficiency

PURPOSE

A reciprocal relationship exists between the skin and the GH/IGF-I axis. Skin produces both IGF- I and vitamin D, and GH and IGF-I exert several actions in the skin. Reduced sweating and altered phosphor-calcium homeostasis are occasionally reported in subjects with GH deficiency (GHD), mostly in the setting of hypopituitarism, therefore associated to other hormonal deficiencies. It is unclear whether these findings are due to GHD. The aim of this study was to assess skin function in subjects with isolated GHD (IGHD) due to a mutation in the GHRH receptor gene.

METHODS

In a cross-sectional study we enrolled 20 IGHD and 20 local controls. Sweating (volume, conductivity and chloride content) was assessed by a 30 min pilocarpine iontophoresis test, using the Macroduct® Sweat Collection System. IGF-I, Insulin, PTH, 25-hydroxyvitamin D, C-reactive protein (CRP), CPK, glucose, calcium, phosphate, alkaline phosphatase, total proteins and fractions, urinary calcium, and insulin were measured. HOMA-IR was calculated.

RESULTS

IGHD presented lower sweating, but normal vitamin D and phosphor-calcium homeostasis. Additionally, IGHD subjects presented lower HOMA-IR, higher CRP and reduced CPK.

CONCLUSION

Untreated IGHD cause reduction in sweating, but does not affect phosphor-calcium homeostasis.

Skin manifestations of growth hormone-induced diseases

The human skin is a well-organized organ bearing different types of cells in a well-structured interference to each other including epidermal and follicular keratinocytes, sebocytes, melanocytes, dermal papilla cells and fibroblasts, endothelial cells, sweat gland cells as well as nerves. Several hormones act on different cell types of the skin, while it is also considered an endocrine organ secreting hormones that act at several sites of the organism. GH receptors are found in almost all cell types forming the skin, while IGF-1 receptors' expression is restricted to the epidermal keratinocytes. Both Growth Hormone (GH) excess, as in the case of Acromegaly in adults, or Gigantism in growing children, and GH deficiency states lead to skin manifestations. In case of GH excess the main dermatological findings are skin thickening, coarsening of facial features, acrochordons, puffy hands and feet, oily skin and hyperhidrosis, while GH deficiency, on the contrary, is characterized by thin, dry skin and disorder of normal sweating. Moreover, special disorders associated with GH excess may have specific characteristics, as is the case of café-au-lait spots in Neurofibromatosis, or big café-au-lait skin hyperpigmented regions with irregular margins, as is the case in McCune-Albright syndrome. Meticulous examination of the skin may therefore contribute to the final diagnosis in cases of GH-induced disorders.

Growth Hormone Influence on the Morphology and Size of the Mouse Meibomian Gland

Purpose. We hypothesize that growth hormone (GH) plays a significant role in the regulation of the meibomian gland. To test our hypothesis, we examined the influence of GH on mouse meibomian gland structure. Methods. We studied four groups of mice, including (1) bovine (b) GH transgenic mice with excess GH; (2) GH receptor (R) antagonist (A) transgenic mice with decreased GH; (3) GHR knockout (−/−) mice with no GH activity; and (4) wild type (WT) control mice. After mouse sacrifice, eyelids were processed for morphological and image analyses. Results. Our results show striking structural changes in the GH-deficient animals. Many of the GHR−/− and GHA meibomian glands featured hyperkeratinized and thickened ducts, acini inserting into duct walls, and poorly differentiated acini. In contrast, the morphology of WT and bGH meibomian glands appeared similar. The sizes of meibomian glands of bGH mice were significantly larger and those of GHA and GHR−/− mice were significantly smaller than glands of WT mice. Conclusions. Our findings support our hypothesis that the GH/IGF-1 axis plays a significant role in the control of the meibomian gland. In addition, our data show that GH modulates the morphology and size of this tissue.

Unusual effects of GH deficiency in adults: a review about the effects of GH on skin, sleep, and coagulation

Based on the literature data in the last two decades, growth hormone deficiency (GHD) in adults has been accepted as a clinical entity. Due to the presence of GH and IGF-I receptors throughout the body, the physiological effects of the GH-IGF-I axis are still under investigation. The effects of GH on skin, sleep, and coagulation parameters in adults have only been investigated in detail only in the recent years. In this review, our aim was to summarize the literature regarding the effects of GHD and GH replacement treatment on the skin, sleep, and coagulation parameters in adults.

Increased glucocorticoid activation during mouse skin wound healing

Glucocorticoid (GC) excess inhibits wound healing causing increased patient discomfort and infection risk. 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activates GCs (converting 11-dehydrocorticosterone to corticosterone in rodents) in many tissues including skin, where de novo steroidogenesis from cholesterol has also been reported. To examine the regulation of 11β-HSD1 and steroidogenic enzyme expression during wound healing, 5 mm wounds were generated in female SKH1 mice and compared at days 0, 2, 4, 8, 14, and 21 relative to unwounded skin. 11β-HSD1 expression (mRNA and protein) and enzyme activity were elevated at 2 and 4 days post-wounding, with 11β-HSD1 localizing to infiltrating inflammatory cells. 11β-HSD2 (GC-deactivating) mRNA expression and activity were undetectable. Although several steroidogenic enzymes displayed variable expression during healing, expression of the final enzyme required for the conversion of 11-deoxycorticosterone to corticosterone, 11β-hydroxylase (CYP11B1), was lacking in unwounded skin and post-wounding. Consequently, 11-deoxycorticosterone was the principal progesterone metabolite in mouse skin before and after wounding. Our findings demonstrate that 11β-HSD1 activates considerably more corticosterone than is generated de novo from progesterone in mouse skin and drives GC exposure during healing, demonstrating the basis for 11β-HSD1 inhibitors to accelerate wound repair.

Extrapituitary growth hormone synthesis in humans

The gene for pituitary growth hormone (GH-N) in man belongs to a multigene locus located at chromosome 17q24.2, which also harbors four additional genes: one for a placental variant of GH-N (named GH-V) and three of chorionic somatommamotropin (CSH) type. Their tandem arrangement from 5' to 3' is: GH-N, CSH-L, CSH-1, GH-V and CSH-2. GH-N is mainly expressed in the pituitary from birth throughout life, while the remaining genes are expressed in the placenta of pregnant women. Pituitary somatotrophs secrete GH into the bloodstream to act at receptor sites in most tissues. GH participates in the regulation of several complex physiological processes, including growth and metabolism. Recently, the presence of GH has been described in several extrapituitary sites, such as neural, ocular, reproductive, immune, cardiovascular, muscular, dermal and skeletal tissues. It has been proposed that GH has an autocrine action in these tissues. While the body of evidence for its presence is constantly growing, research of its possible function and implications lag behind. In this review we highlight the evidence of extrapituitary synthesis of GH in humans.

Adenoviral-mediated gene transfer of insulin-like growth factor 1 enhances wound healing and induces angiogenesis

BACKGROUND

Chronic wounds are characterized by a wound healing and neovascularization deficit. Strategies to increase neovascularization can significantly improve chronic wound healing. Insulin-like growth factor (IGF)-1 is reported to be a keratinocyte mitogen and is believed to induce angiogenesis via a vascular endothelial growth factor (VEGF)-dependent pathway. Using a novel ex vivo human dermal wound model and a diabetic-impaired wound healing murine model, we hypothesized that adenoviral overexpression of IGF-1 (Ad-IGF-1) will enhance wound healing and induce angiogenesis through a VEGF-dependent pathway.

METHODS

Ex vivo: 6-mm full-thickness punch biopsies were obtained from normal human skin, and 3-mm full-thickness wounds were created at the center. Skin explants were maintained at air liquid interface. Db/db murine model: 8-mm full-thickness dorsal wounds in diabetic (db/db) mice were created. Treatment groups in both human ex vivo and in vivo db/db wound models include 1×10(8) particle forming units of Ad-IGF-1 or Ad-LacZ, and phosphate buffered saline (n=4-5/group). Cytotoxicity (lactate dehydrogenase) was quantified at days 3, 5, and 7 for the human ex vivo wound model. Epithelial gap closure (hematoxylin and eosin; Trichrome), VEGF expression (enzyme-linked immunosorbent assay), and capillary density (CD 31+CAPS/HPF) were analyzed at day 7.

RESULTS

In the human ex vivo organ culture, the adenoviral vectors did not demonstrate any significant difference in cytotoxicity compared with phosphate buffered saline. Ad-IGF-1 overexpression significantly increases basal keratinocyte migration, with no significant effect on epithelial gap closure. There was a significant increase in capillary density in the Ad-IGF-1 wounds. However, there was no effect on VEGF levels in Ad-IGF-1 samples compared with controls. In db/db wounds, Ad-IGF-1 overexpression significantly improves epithelial gap closure and granulation tissue with a dense cellular infiltrate compared with controls. Ad-IGF-1 also increases capillary density, again with no significant difference in VEGF levels in the wounds compared with control treatments.

CONCLUSIONS

In two different models, our data demonstrate that adenoviral-mediated gene transfer of IGF-1 results in enhanced wound healing and induces angiogenesis via a VEGF-independent pathway. Understanding the underlying mechanisms of IGF-1 effects on angiogenesis may help produce novel therapeutics for chronic wounds or diseases characterized by a deficit in neovascularization.

Adenoviral-mediated gene transfer of insulin-like growth factor 1 enhances wound healing and induces angiogenesis

BACKGROUND

Chronic wounds are characterized by a wound healing and neovascularization deficit. Strategies to increase neovascularization can significantly improve chronic wound healing. Insulin-like growth factor (IGF)-1 is reported to be a keratinocyte mitogen and is believed to induce angiogenesis via a vascular endothelial growth factor (VEGF)-dependent pathway. Using a novel ex vivo human dermal wound model and a diabetic-impaired wound healing murine model, we hypothesized that adenoviral overexpression of IGF-1 (Ad-IGF-1) will enhance wound healing and induce angiogenesis through a VEGF-dependent pathway.

METHODS

Ex vivo: 6-mm full-thickness punch biopsies were obtained from normal human skin, and 3-mm full-thickness wounds were created at the center. Skin explants were maintained at air liquid interface. Db/db murine model: 8-mm full-thickness dorsal wounds in diabetic (db/db) mice were created. Treatment groups in both human ex vivo and in vivo db/db wound models include 1×10(8) particle forming units of Ad-IGF-1 or Ad-LacZ, and phosphate buffered saline (n=4-5/group). Cytotoxicity (lactate dehydrogenase) was quantified at days 3, 5, and 7 for the human ex vivo wound model. Epithelial gap closure (hematoxylin and eosin; Trichrome), VEGF expression (enzyme-linked immunosorbent assay), and capillary density (CD 31+CAPS/HPF) were analyzed at day 7.

RESULTS

In the human ex vivo organ culture, the adenoviral vectors did not demonstrate any significant difference in cytotoxicity compared with phosphate buffered saline. Ad-IGF-1 overexpression significantly increases basal keratinocyte migration, with no significant effect on epithelial gap closure. There was a significant increase in capillary density in the Ad-IGF-1 wounds. However, there was no effect on VEGF levels in Ad-IGF-1 samples compared with controls. In db/db wounds, Ad-IGF-1 overexpression significantly improves epithelial gap closure and granulation tissue with a dense cellular infiltrate compared with controls. Ad-IGF-1 also increases capillary density, again with no significant difference in VEGF levels in the wounds compared with control treatments.

CONCLUSIONS

In two different models, our data demonstrate that adenoviral-mediated gene transfer of IGF-1 results in enhanced wound healing and induces angiogenesis via a VEGF-independent pathway. Understanding the underlying mechanisms of IGF-1 effects on angiogenesis may help produce novel therapeutics for chronic wounds or diseases characterized by a deficit in neovascularization.

Difficult venepuncture--it was all in the head!

AIM

To emphasise the importance of careful observations and demonstrate that significant conditions may, on occasion, be detected during blood donation.

BACKGROUND

Venepunctures, the bread and butter of blood donor services, can be difficult procedures. We describe an unusual presentation of a relatively rare disease detected during routine blood donations because of difficult venepunctures.

METHODS

Case report.

RESULTS

A growth hormone-secreting pituitary adenoma was diagnosed, and successfully treated, following the initial observation of hard-to-puncture skin during blood donations.

CONCLUSIONS

Seemingly trivial abnormalities may prove clinically important. One presentation of acromegaly is hard-to-puncture skin.

Growth hormone system: skin interactions

This paper describes the growth hormone system, emphasizing its possible effects on epidermal cells, dermal structures and wound healing. A review of the literature was conducted on studies concerning the growth hormone molecule, its receptor and carrier proteins and the other proteins involved in the mechanisms of its manifestation in dermal tissue.

Acromegaly is associated with decreased skin transepidermal water loss and temperature, and increased skin pH and sebum secretion partially reversible after treatment

BACKGROUND

Acromegaly is characterized by an acquired progressive somatic disfigurement, mainly involving the face and extremities, besides many other organ involvement. Wet and oily skin was described in acromegaly patients and it was attributed to hyperhidrosis and increased sebum production but this suggestion has not been evaluated with reliable methods.

OBJECTIVE

The aim of this study was to examine the skin parameters of patients with acromegaly using measurements of skin hydration, sebum content, transepidermal water loss, pH and temperature and particularly the effects of 12 months of treatment on these parameters.

METHODS

52 patients with acromegaly and 24 healthy control subjects were included in this two blinded prospective study. Skin properties were measured on forehead and forearm by Corneometer CM825, Sebumeter SM810, Tewameter TM210 and Phmeter PH900 as non-invasive reliable measuring methods. Serum GH, IGF-1 and all measurements of skin properties on forehead and forearm were repeated at the end of the 3, and 6 months of therapy in 20 cases. Patients were treated with appropriate replacement therapy for deficient pituitary hormones.

RESULTS

The sebum content and pH of the skin of acromegalic patients were significantly higher and transepidermal water loss and skin temperature were found to be significantly lower in acromegalic patients when compared to the control group both on forehead and forearm. GH and IGF-1 levels were positively correlated with sebum levels and negatively correlated with skin temperature on both forehead and forearm. The sebum levels of the patients were significantly decreased both on forehead and forearm at 3rd and 6th months of treatment.

CONCLUSION

The present study demonstrated increased sebum secretion, decreased transepidermal water loss, alkali and hypothermic skin surface in patients with acromegaly by reliable methods for the first time. These data suggest that GH and/or IGF-I may have a modulatory role on several skin characteristics which can be at least partially reversible with treatment.

Normal sweat secretion despite impaired growth hormone-insulin-like growth factor-I axis in obese subjects

Adults with GH deficiency are known to exhibit reduced sweating. Whether sweating capacity is impacted in obese subjects with impaired GH secretion have not previously been investigated. The main objective was to investigate sweat secretion rate and the GH-IGF-I axis in obese subjects before and after weight loss. Sixteen severely obese women (BMI, 40.6 ± 1.1 kg/m(2)) were investigated before and after a diet-induced weight loss. Sixteen age-matched nonobese women served as controls. The obese subjects presented the characteristic decreased GH release, hyperinsulinaemia, increased FFA levels, and impaired insulin sensitivity, which all were normalised after diet-induced weight loss of 30 ± 5 kg. Sweat secretion rates were similar comparing obese and nonobese subjects (78 ± 10 versus 82 ± 9 mg/30 minutes) and sweat secretion did not change after a diet-induced weight loss in obese subjects. We conclude that although obese subjects have markedly reduced GH release and impaired IGF-I levels, sweat secretion rate is found to be normal.

Overexpression of mIGF-1 in keratinocytes improves wound healing and accelerates hair follicle formation and cycling in mice

Insulin-like growth factor 1 (IGF-1) is an important regulator of growth, survival, and differentiation in many tissues. It is produced in several isoforms that differ in their N-terminal signal peptide and C-terminal extension peptide. The locally acting isoform of IGF-1 (mIGF-1) was previously shown to enhance the regeneration of both muscle and heart. In this study, we tested the therapeutic potential of mIGF-1 in the skin by generating a transgenic mouse model in which mIGF-1 expression is driven by the keratin 14 promoter. IGF-1 levels were unchanged in the sera of hemizygous K14/mIGF-1 transgenic animals whose growth was unaffected. A skin analysis of young animals revealed normal architecture and thickness as well as proper expression of differentiation and proliferation markers. No malignant tumors were formed. Normal homeostasis of the putative stem cell compartment was also maintained. Healing of full-thickness excisional wounds was accelerated because of increased proliferation and migration of keratinocytes, whereas inflammation, granulation tissue formation, and scarring were not obviously affected. In addition, mIGF-1 promoted late hair follicle morphogenesis and cycling. To our knowledge, this is the first work to characterize the simultaneous, stimulatory effect of IGF-1 delivery to keratinocytes on two types of regeneration processes within a single mouse model. Our analysis supports the use of mIGF-1 for skin and hair regeneration and describes a potential cell type-restricted action.

Effect of topical application of raspberry ketone on dermal production of insulin-like growth factor-I in mice and on hair growth and skin elasticity in humans

Sensory neurons release calcitonin gene-related peptide (CGRP) on activation. We recently reported that topical application of capsaicin increases facial skin elasticity and promotes hair growth by increasing dermal insulin-like growth factor-I (IGF-I) production through activation of sensory neurons in mice and humans. Raspberry ketone (RK), a major aromatic compound contained in red raspberries (Rubus idaeus), has a structure similar to that of capsaicin. Thus, it is possible that RK activates sensory neurons, thereby increasing skin elasticity and promoting hair growth by increasing dermal IGF-I production. In the present study, we examined this possibility in mice and humans. RK, at concentrations higher than 1 microM, significantly increased CGRP release from dorsal root ganglion neurons (DRG) isolated from wild-type (WT) mice and this increase was completely reversed by capsazepine, an inhibitor of vanilloid receptor-1 activation. Topical application of 0.01% RK increased dermal IGF-I levels at 30 min after application in WT mice, but not in CGRP-knockout mice. Topical application of 0.01% RK increased immunohistochemical expression of IGF-I at dermal papillae in hair follicles and promoted hair re-growth in WT mice at 4 weeks after the application. When applied topically to the scalp and facial skin, 0.01% RK promoted hair growth in 50.0% of humans with alopecia (n=10) at 5 months after application and increased cheek skin elasticity at 2 weeks after application in 5 females (p<0.04). These observations strongly suggest that RK might increase dermal IGF-I production through sensory neuron activation, thereby promoting hair growth and increasing skin elasticity.

Association of COLIA1 Sp1 polymorphism with the effect of subcutaneously injected recombinant hGH in GH-deficient adults

Objective: Collagen type I is a common structural protein in bone and skin. Similar to its association with the mechanical properties of the skeleton and, thus, bone-fracture risk, the collagen type I α (COLIA)-1 specific protein (Sp)-1 polymorphism may be related to variations in the collagen type I-containing subcutaneous tissue and its biological properties. In this study, we analyzed a possible influence of the COLIA1 Sp1 polymorphism on the effect of subcutaneously injected recombinant human growth hormone (hGH) in GH-deficient adults. Materials & methods: We determined the COLIA1 Sp1 polymorphism in 122 adults with GH deficiency of different origin, who were derived from the prospective Pfizer International Growth Database (KIMS) Pharmacogenetics Study. Inclusion criteria were subcutaneous applied treatment with hGH for over 12 months, finished dose titration of hGH by following serum IGF-1 concentrations until desired levels were achieved, and centralized, standardized IGF-1 measurements. The genotypes (GG/GT/TT) were statistically related to clinical data from the KIMS database. Results: The dose of injected hGH was significantly related to the COLIA1 Sp1 genotypes (p = 0.049), whereby the GG homozygotes were treated with a significantly higher dose of hGH than TT homozygotes (p = 0.03). Accordingly, the IGF-1:GH ratios were significantly lower in GG compared with TT homozygotes (p = 0.04). Both groups showed no significant differences in their IGF-1 serum concentrations (p = 0.98) and IGF-1 SDS (p = 0.79). Conclusion: The COLIA1 Sp1 polymorphism is related to the dose of individually required, subcutaneous injected hGH in GH-deficient adults, probably because of an alteration of the subcutaneous collagen type I structure, content and/or biological/biomechanical properties. GG homozygotism, which is related to a more stable bone structure and decreased fracture risk, may impact skin resistance to subcutaneous injected protein-based drugs, as shown for hGH in this study.

Effect of topical application of capsaicin and its related compounds on dermal insulin-like growth factor-I levels in mice and on facial skin elasticity in humans

Capsaicin increases calcitonin gene-related peptide (CGRP) release from sensory neurons by stimulating vanilloid receptor-1 (VR-1). Since CGRP increases production of insulin-like growth factor-I (IGF-I) in fetal osteoblasts in vitro, it is possible that sensory neuron activation by capsaicin increases production of IGF-I. In the present study, we attempted to determine whether topical application of capsaicin and related compounds increases dermal IGF-I level in mice and whether it increases facial skin elasticity in humans. Topical application of 0.01% capsaicin significantly increased dermal IGF-I levels from 30 to 180min (p<0.01), but not at 360min, after application in mice. Topical application of 0.01% capsaicinoids (dihydrocapsaicin and nordihydrocapsaicin), 0.01% capsinoids (capsiate, dihydrocapsiate and nordihydrocapsiate), 0.01% anandamide (an endogenous agonist of VR-1), and 0.01% nonylic acid vanillylamide (a synthetic capsaicin) significantly increased dermal IGF-I levels at 30min after topical application in mice (p<0.01). Topical application of 0.01% capsaicin to faces of 17 healthy female volunteers for seven days significantly increased cheek skin elasticity (p<0.01). These observations suggest that topical application of capsaicin and related compounds might be useful in the treatment of detrimental morphological changes of the skin in patients with growth hormone deficiency and those in the elderly by increasing dermal IGF-I levels.

The effects of severe growth hormone deficiency on the skin of patients with Sheehan's syndrome

BACKGROUND

Growth hormone (GH) may play an important role in the content and appearance of the skin. Dry, thin and pale skin has been described in hypopituitarism. Sheehan's syndrome is characterized by anterior pituitary dysfunction due to postpartum pituitary necrosis and GH is one of the hormones lost first.

OBJECTIVE

The aim of this study was to examine the hydration of the skin of patients with Sheehan's syndrome using measurements of capacitance, sebum content, transepidermal water loss, pH and temperature. The data were compared with those of control subjects.

METHODS

A total of 21 patients with Sheehan's syndrome and 20 women as control subjects were included in this blinded prospective study. Hormone deficiencies other than GH had been adequately replaced. The diagnosis of GH deficiency (GHD) was established by the insulin tolerance test (ITT). Skin properties were measured by non-invasive and well-established methods.

RESULTS

The skin capacitance had decreased on the forehead and forearm and sebum content had decreased on the forehead of patients with Sheehan's syndrome when compared with control subjects. The pH, temperature and average transepidermal water loss (TEWL) of the skin of the patients were not statistically different from the controls.

CONCLUSION

GHD results in a decrease in skin capacitance and sebum content indicating that GH and/or insulin-like growth factor-I (IGF-I) have an important role in skin function.

Investigation of the skin characteristics in patients with severe GH deficiency and the effects of 6 months of GH replacement therapy: a randomized placebo controlled study

OBJECTIVE

The presence of GH receptor in human skin and its appendages suggests a direct effect of GH on skin characteristics. The skin is usually thin and dry in patients with GH deficiency (GHD). Sheehan's syndrome classically refers to postpartum hypopituitarism and GH is one of the earliest pituitary hormones lost. While severe GHD is a well-established feature of Sheehan's Syndrome, skin characteristics and the effects of GH replacement therapy (GHRT) have been investigated neither in Sheehan's syndrome nor in other disorders of GHD. The aim of this study was to investigate the skin characteristics, including the sebum content, hydration (skin capacitance), transepidermal water loss (TEWL), pH and skin temperature, and particularly the effects of 6 months of GHRT on these parameters in GH deficient patients with Sheehan's syndrome.

PATIENTS AND DESIGN

Sixteen severely GH deficient women with Sheehan's syndrome (48.1 +/- 10.9 years), and 20 age and menopausal status similar women as control subjects were included. Ten patients received recombinant GH for 6 months (treatment group) and 6 patients received placebo (placebo group) during this period. Skin properties were measured at baseline and after 6 months of GHRT using noninvasive and well-established measuring methods.

RESULTS

At baseline the skin capacitance was significantly decreased on the forehead and forearm, and sebum content was significantly decreased on forehead in patients with Sheehan's syndrome compared to control subjects (P < 0.05). In the treatment group there was a significant increase in sebum content on forehead after 6 months of GHRT compared to the baseline value (P < 0.05). However there were no significant changes in other parameters including sebum content on the forearm, TEWL, Ph, skin capacitance and temperature of both the forearm and forehead. In the placebo group there were no changes in any of the evaluated parameters after 6 months of treatment compared to baseline values.

CONCLUSIONS

The present study clearly shows that the sebum content on the forehead and skin hydration of the forehead and forearm are significantly decreased in GH deficient patients with Sheehan's syndrome. However 6 months of GHRT significantly increased only the sebum content on the forehead. These data suggest that GH and/or IGF-I may have a modulatory role on several skin characteristics.

Dermatologic manifestations of hypopituitarism

Hypopituitarism is characterized by diminished or absent secretion of one or more pituitary hormones. The clinical features of hypopituitarism vary depending on age, rapidity of onset, hormones involved, and degree of deficiency. Dermatologic signs of hypopituitarism may involve alterations in pigmentation, the epidermal and dermal skin structures, and the pilosebaceous unit. We describe the causes and presentation of hypopituitarism with an emphasis on its dermatologic manifestations.

Skin manifestations in acromegaly

Cutaneous changes in acromegaly result from excess GH and IGF-1 action on skin cells and adnexae. Skin puffiness due to dermal glycosaminoglycan accumulation and edema are most prominent in the face, hands and feet. Oily skin with large pores, hypertrichosis, and excessive sweating are common features. Pigmented skin tags, acanthosis nigricans, and psoriasis are also encountered. Alteration in skin capillaries produce increased vasoconstriction. Discerning these changes contributes to early diagnosis and treatment of this high-morbidity disorder. Controlling GH and IGF-1 over-secretion alleviates most cutaneous manifestations of acromegaly; however, regression may be incomplete.

Growth hormone and connective tissue in exercise

Over the last few years, growth hormone (GH) has become increasingly popular as doping within different sports. However, the precise mechanisms behind the ergogenic (performance enhancing) effects of GH in athletes are still being debated. Besides a well-documented stimulatory effect of GH on carbohydrate and fatty acid metabolism, and a possible anabolic effect on myofibrillar muscle protein, we suggest a role for GH as an anabolic agent in connective tissue in human skeletal muscle and tendon. Given the importance of the connective tissue for the function of skeletal muscle and tendon, a strengthening effect of GH on connective tissue could fit with the ergogenic effect of GH experienced by athletes. This review examines the endogenous secretion of GH and its mediators in relation to exercise. Furthermore, we consider the effect of endogenous GH and administered recombinant human GH (rhGH) on both myofibrillar and connective tissue protein synthesis, thus offering an alternative explanation for the ergogenic effect of GH. Finally, we suggest a possible therapeutic role for rhGH in clinical management of the frequently suffered injuries in the connective tissue.

Abnormal bone collagen morphology and decreased bone strength in growth hormone-deficient rats

Patients with growth hormone deficiency (GHD) have an increased risk of bone fractures. In these patients, the well-described decrease in bone mineral density (BMD) and content (BMC) may, however, not alone explain the increase in fracture rate. Accordingly, the aim of this study was to evaluate collagen morphology and bone mineralisation in cortical bone as well as bone strength in GHD rats to try to clarify the explanation for the increased fracture rate. The Dw-4 rat was used as a model for GHD. This strain of rats has an autosomal recessive disorder, reducing GH synthesis to approximately 10% and growth rate to approximately 40-50% when compared to normal control rats. Five male Dw-4 rats were examined at age 12 weeks and five healthy Lewis rats served as age-matched controls. The animals were examined for (1) bone mineral status by dual energy X-ray absorptometry (DXA) and ash weight/bone volume, (2) biomechanical properties, (3) serum insulin-like growth factor I (IGF-I) and IGF binding protein 3 (IGFBP-3), and (4) collagen morphology of cortical bone from the right femurs was examined by scanning and transmission electron microscopy. A significant decrease was found in serum IGF-I, IGFBP-3 and biomechanical properties in GHD rats compared to controls (P < 0.009). While DXA-derived BMD was decreased, no significant difference was found in ash weight/bone volume. Electron microscopy showed a significant decrease in the number and a significant increase in the diameter of collagen microfibrils in GHD rats as compared to their controls (P < 0.009). In conclusion, we report for the first time that collagen morphology in bone is markedly altered in rats with isolated GHD. Whether similar conditions are present in GHD patients need further investigations. The changes described, however, may provide a co-explanation for the increased fracture rate in GHD.

Epidermal homeostasis: the role of the growth hormone and insulin-like growth factor systems

GH and IGF-I and -II were first identified by their endocrine activity. Specifically, IGF-I was found to mediate the linear growth-promoting actions of GH. It is now evident that these two growth factor systems also exert widespread activity throughout the body and that their actions are not always interconnected. The literature highlights the importance of the GH and IGF systems in normal skin homeostasis, including dermal/epidermal cross-talk. GH activity, sometimes mediated via IGF-I, is primarily evident in the dermis, particularly affecting collagen synthesis. In contrast, IGF action is an important feature of the dermal and epidermal compartments, predominantly enhancing cell proliferation, survival, and migration. The locally expressed IGF binding proteins play significant and complex roles, primarily via modulation of IGF actions. Disturbances in GH and IGF signaling pathways are implicated in the pathophysiology of several skin perturbations, particularly those exhibiting epidermal hyperplasia (e.g., psoriasis, carcinomas). Additionally, many studies emphasize the potential use of both growth factors in the treatment of skin wounds; for example, burn patients. This overview concerns the role and mechanisms of action of the GH and IGF systems in skin and maintenance of epidermal integrity in both health and disease.

Reduced capillary permeability and capillary density in the skin of GH-deficient adults: improvement after 12 months GH replacement

OBJECTIVE

Several lines of evidence suggest that the GH-IGF-1 axis affects capillary permeability and angiogenesis. We evaluated skin capillary permeability and capillary density in GH-deficient adults, before and after GH replacement therapy.

PATIENTS

Seven normotensive, nondiabetic GH-deficient adults (two women) were matched with 14 control subjects.

MEASUREMENTS

Large-window videodensitometry with sodium fluorescein was performed in all subjects. Capillary permeability was expressed as the average relative light intensity over the first 7 min after the appearance of fluorescein in the skin capillaries; Iav(7). Skin capillary density was determined by counting the visualized capillaries and was expressed as n/mm2. The GH-deficient patients were restudied after 12 months of GH replacement therapy (2 U/day).

RESULTS

Both capillary permeability and capillary density were lower in untreated GH-deficient patients than in control subjects (median, interquartile range): Iav(7) in GH-deficient patients 47.1 (45.1-52.2)% vs. 57.5 (50.5-64.8)% in controls, P < 0.05; capillary density in GH-deficient patients 18 (12-24)/mm2 vs. 32 (26-36)/mm2 in controls, P < 0.05. GH treatment normalized plasma IGF-1 from 4.3 (1.0-13.4) to 22.2 (19.8-48.2) nmol/l (P < 0.05). Furthermore, both capillary permeability [Iav(7) 53.1 (48.8-58.4)%, P < 0.05] and capillary density [26 (17-34)/mm2, P < 0.05] increased to a level that was not different from that in control subjects.

CONCLUSIONS

The present study demonstrates that the growth hormone deficiency syndrome is associated with microvascular alterations, which are responsive to growth hormone replacement therapy.