Recombinant human growth hormone modulates the hepatic acute-phase response and P-selectin in burned rats

The Modulatory Role of Growth Hormone in Inflammation and Macrophage Activation

Inflammation is a body's response to remove harmful stimuli and heal tissue damage, which is involved in various physiology and pathophysiology conditions. If dysregulated, inflammation may lead to significant negative impacts. Growth hormone (GH) has been shown responsible for not only body growth but also critical in the modulation of inflammation. In this review, we summarize the current clinical and animal studies about the complex and critical role of GH in inflammation. Briefly, GH excess or deficiency may lead to pathological inflammatory status. In inflammatory diseases, GH may serve as an inflammatory modulator to control the disease progression and promote disease resolution. The detailed mechanisms and signaling pathways of GH on inflammation, with a focus on the modulation of macrophage polarization, are carefully discussed with potential direction for future investigations.

Zinc Sulfate and/or Growth Hormone Administration for the Prevention of Radiation-Induced Dermatitis: a Placebo-Controlled Rat Model Study

Growth hormone (GH) and zinc (Zn) were evaluated for their potential to prevent radiation injury using a rat model of radiation-induced skin injury. Sprague-Dawley rats were divided into five groups: a control group not receiving Zn, GH, or irradiation: a radiation (RT) group receiving a single 30 Gy dose of gamma irradiation to the right hind legs; a radiation + GH group (RT + GH) receiving a single 30 Gy dose of gamma irradiation plus the subcutaneous administration of 0.01 IU kg d^-1 GH; a radiation + Zn group (RT + Zn) receiving a single 30 Gy dose plus 5 mg kg d^-1 Zn po; and a radiation + GH + Zn group (RT + GH + Zn) group receiving a single 30 Gy dose plus subcutaneous 0.01 IU kg d^-1 GH and 5 mg kg d^-1 Zn po. Acute skin reactions were assessed every 3 days by two radiation oncologists grouping. Light microscopic findings were assessed blindly by two pathologists. Groups receiving irradiation were associated with dermatitis as compared to the control group (P < 0.05). The severity of radiodermatitis in the RT + GH, RT + Zn, and RT + GH + Zn groups was significantly lower than that in the RT group (P < 0.05). Furthermore, radiodermatitis was observed earlier in the RT group than in the other treatment groups (P < 0.05). GH and Zn effectively prevented epidermal atrophy, dermal degeneration, and hair follicle atrophy. The highest level of protection against radiation dermatitis was observed in the combination group.

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.

Is growth hormone a radioprotective agent?

There is currently substantial clinical interest in growth hormone (GH) as a protective agent against radiation-related normal tissue injury. To further assess the potential radiation injury-preventive effects of GH, these effects were studied in rats by using a radiation-induced skin injury model. Group 1 received neither GH nor irradiation (control group). Group 2 received 30 Gy of gamma irradiation as a single dose to the right hind legs of the rats (radiation group). Group 3 and 4 received the same irradiation plus either 0.01 U/kg/day GH (RT + 0.01 GH group) or 0.02 U/kg/day GH (RT + 0.02 GH group) subcutaneously. Clinically and histopathologically, acute skin reactions were assessed by two independent experts in radiation oncology and pathology, respectively. Irradiation increased dermatitis in rats when compared with the control group. The severity of radiodermatitis in the rats in the RT + 0.01 GH and RT + 0.02 GH groups was significantly lower than that in the RT group; radiodermatitis developed earlier in the RT group than in the other groups. GH was efficacious in preventing epidermal atrophy, dermal degeneration such as oedema and collagen fibre loss, and hair follicle atrophy, but not better than in the control group. These results are preliminary to studies that will be performed with higher doses of GH in radiation-treated cancer patients, with the aim of reducing radiation-induced toxicity.