Somatostatin treatment of psoriasis

Neurotransmitters, neuropeptides and their receptors interact with immune response in healthy and psoriatic skin

Psoriasis is a chronic inflammatory disease with a multifactorial origin that affects the skin. It is characterized by keratinocyte hyperproliferation, which results in erythemato-squamous plaques. Just as the immune system plays a fundamental role in psoriasis physiopathology, the nervous system maintains the inflammatory process through the neuropeptides and neurotransmitters synthesis, as histamine, serotonin, calcitonin gene-related peptide, nerve growth factor, vasoactive intestinal peptide, substance P, adenosine, glucagon-like peptide, somatostatin and pituitary adenylate cyclase polypeptide. In patients with psoriasis, the systemic or in situ expression of these chemical mediators and their receptors are altered, which affects the clinical activity of patients due to its link to the immune system, provoking neurogenic inflammation. It is important to establish the role of the nervous system since it could represent a therapeutic alternative for psoriasis patients. The aim of this review is to offer a detailed review of the current literature about the neuropeptides and neurotransmitters involved in the physiopathology of psoriasis.

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.

Psoriasis in association with prolactinoma: three cases

We report three women with plaque-type psoriasis in whom increase in severity and extent of the skin lesions correlated with the development of a prolactinoma. In all three patients, administration of bromocriptine, a dopamine agonist that suppresses the secretion of prolactin, improved the therapeutic response of the psoriasis. To our knowledge, there are no reports of an association between psoriasis and prolactinoma. In recent years it has become apparent that prolactin plays an important part in the immune reactions and exerts a proliferative effect on human keratinocytes. We, therefore, discuss the part that prolactin may play in the pathogenesis of psoriasis.

No evidence for involvement of the growth hormone/insulin-like growth factor-1 axis in psoriasis

We have examined whether alterations in the growth hormone/insulin-like growth factor-1 axis play a role in the pathogenesis of psoriasis. Serum, urine, full skin biopsies, and suction blister roofs were obtained from patients with psoriasis and from healthy controls. Serum concentrations of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 were measured by radioimmunoassay. Growth hormone-binding protein was measured by ligand-mediated immunofunctional assay. Growth hormone concentration in urine was measured by an immunometric assay, and growth hormone receptor-gene expression was measured by RNase protection assay or by quantitative reverse transcriptase polymerase chain reaction in total RNA isolated from epidermal suction blister roofs. Serum concentrations of insulin-like growth factor-1 (249 +/- 12 micrograms per liter, mean +/- SEM, n = 42, and 277 +/- 21 micrograms per liter, n = 9, for psoriatic patients and controls, respectively), insulin-like growth factor binding protein-3 (3.1 +/- 0.08 mg per liter, n = 42, and 3.3 +/- 0.22 mg per liter, n = 9), growth hormone-binding protein (344 +/- 65 pmol per liter, n = 10, and 311 +/- 83 pmol per liter, n = 9), urinary growth hormone excretion during 24 h (12.8 +/- 2.7 microIU per 24 h, n = 12, and 12.3 +/- 1.6 microIU per 24 h, n = 9), and epidermal growth hormone receptor gene expression [32 +/- 12 x 10(3) mRNA transcripts per microgram total RNA (involved skin), n = 11, and 47 +/- 14 x 10(3) mRNA transcripts per microgram total RNA, n = 9] were similar in patients and controls. For insulin-like growth factor-1 and insulin-like growth factor binding protein-3 the values in psoriatic patients were also similar to those in larger control groups, n = 195 and n = 400, respectively. In addition, we found no evidence of local expression of growth hormone or prolactin in full skin punch biopsies from psoriatic involved skin by reverse transcriptase polymerase chain reaction. In conclusion, our results suggest that alterations in the growth hormone/ insulin-like growth factor-1 axis do not play a major role in the pathogenesis of psoriasis.

Treatment of psoriatic arthropathy

Psoriatic arthritis develops in 5% of patients with cutaneous psoriasis. Management is similar to that of other chronic inflammatory joint diseases, and the characteristic features of psoriatic arthritis should be considered: the disease is usually mild, with unpredictable flares and remissions, and skin disease is a concomitant feature. Nonsteroidal antiinflammatory agents are the mainstay of therapy and usually provide adequate control. Among long-term treatments, parenteral gold salts, methotrexate, and azathioprine have been shown to be effective. Retinoids are often used in patients with extensive skin lesions. Other treatments are currently being evaluated (auranofin, colchicine, D-penicillamine, sulfasalazine, cyclosporine, and gamma-interferon). Antimalarials are difficult to handle and may cause progression of skin lesions. Topical treatments are indicated in every case. Indications depend on the specific features of psoriatic arthritis, the clinical pattern, and the severity of the condition.

Acromegaly and psoriasis

A 56-year-old man with long-standing chronic plaque psoriasis was noted to be acromegalic. Investigations confirmed the presence of a large pituitary adenoma and following treatment of this by hypophysectomy his psoriasis cleared dramatically within 3 weeks.

Somatostatin treatment of psoriatic arthritis

Eighteen patients with psoriatic arthritis were treated for 48 hours with an infusion of somatostatin 250 micrograms/hr diluted in a 5% glucose solution. This therapy led to a reduction of joint pain and satisfactory clearing of cutaneous lesions immediately after treatment in eight patients, less marked results in four, and null in four. Two patients were dropped from the study because of negative side effects during administration of the drug. Fifteen days after treatment, the clearing of lesions and joint pain reduction were even more pronounced. The most encouraging results were obtained on erythrodermic and large plaque psoriasis and on the polyarticular involvement. We suggest that the use of this drug, whose side effects are discussed, should be limited to patients with polyarthritis showing severe cutaneous involvement.

Plasma somatomedin-C levels in psoriasis

We have measured plasma levels of somatomedin-C, one of the principal mediators of growth hormone action, in 25 patients with plaque-type psoriasis of varying severity and compared these levels with those found in healthy controls. Plasma somatomedin-C levels were not elevated in the psoriatic patients regardless of the severity of their disease, suggesting that in these patients growth hormone secretion is within normal limits.