Depigmentation efficacy of galacturonic acid through tyrosinase regulation in B16 murine melanoma cells and a three-dimensional human skin equivalent

Sugar is a well-known cosmetic ingredient for moisturizing skin with minimal side-effects. Several reports have demonstrated an antimelanogenic effect of sugar in melanocytes. We evaluated the whitening efficacy of galacturonic acid (GA), the main component of pectin, as an anti-melanogenic agent. GA significantly suppressed melanin synthesis and secretion in a concentration-dependent manner in α-melanocyte stimulating hormone-treated B16 melanoma cells, and inhibited tyrosinase activity and expression at a dose of 10 mmol/L. In a three-dimensional human skin equivalent (MelanoDerm), GA clearly brightened tissue colour. Haematoxylin and eosin and Fontana-Masson (F&M) staining of tissue sections revealed decreased melanin production without skin tissue collapse in the presence of GA. Interestingly, GA dramatically suppressed gene expression of the melanogenic proteins tyrosinase, tyrosinase-related protein (TYRP)-1 and microphthalmia-associated transcription factor, but not TYRP-2. The results support the utility of GA as an effective candidate antimelanogenic agent.

The effect of lipopolysaccharide on enhanced inflammatory process with age: Modulation of NF-κB

Oxidative stress is thought to be a causative factor for age-related damage in a wide variety of cellular constituents that can lead to dysfunction and various pathological conditions, including the inflammatory process. At the molecular level, the redox-sensitive transcription factor, NF-κB plays a key role in the regulation of the inflammatory process, along with cytokines, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). We studied the mechanism underlying the modulation of the inflammatory reaction with age by investigating NF-κB activation and the expression of COX-2, iNOS, and cytokines genes in hepatic tissues isolated from young and old rats. We expanded our investigation of these factors in rats injected with the inflammatory activator, lipopolysaccharide (LPS). Data showed that NF-κB activity was up-regulated with age and was further enhanced by LPS injection, indicating an increased susceptibility and sensitivity to the inflammatory stimulus with age. To explore further the molecular events leading to NF-κB activation, we investigated the inhibitory component of NF-κB complex, IκB. Cytosolic IκBα, but not IκBβ, was significantly decreased in both old and LPS-treated rats, signifying the enhanced migration of cytosolic NF-κB complex into the nucleus following dissociation from the inhibitor. The appearance of the polypeptide, p65, as determined in the nucleus, corresponded with the change in IκBα, providing further supporting evidence for the molecular process involved in NF-κB activation. Our additional investigation of two proinflammatory-related enzymes, COX-2 and iNOS, and three cytokines, interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α, clearly showed aged-related increases, in corroboration with the NF-κB activation. Our results demonstrated that LPS injection caused the enhanced gene expression of inducible proinflammatory proteins, COX-2 and iNOS through NF-κB activation.

Comparison of peripheral nerve damages according to glucose control timing in experimental diabetes

OBJECTIVE

In addition to tight glucose control, early intensive therapy has been reported to be more important for the prevention of diabetic micro- and macro-vascular complications. What is not known exactly is the quantitative difference according to timing delay in glucose control and whether early period control is really better than late control in terms of diabetic peripheral neuropathy. In this study, we investigated the effect of timing differences in glucose control on the peripheral nerves in an experimental diabetic model.

METHODS

5 groups (6-8 rats in each group) were comprised of normal glucose rats (designated control), rats with hyperglycemia (designated DM), rats with glucose control for the entire 28-week study period (designated DM + INS [W0-28]), rats with glucose control for the early 14-week period followed by hyperglycemia for the late 14-week period (designated DM + INS [W0-14]), and rats with hyperglycemia for the early 14-week period followed by glucose control in the late 14-week period (designated DM + INS [W15-28]).

RESULTS

We found that the current perception threshold (CPT) was lower in the DM + INS (W0-28) and DM + INS (W15-28) groups than in the DM + INS (W0-14) or DM groups (P<0.05). The mean myelinated fiber area of the sciatic nerve was significantly greater in the DM + INS (W0-28) and DM + INS (W15-28) groups (63.5±2.32 and 60.1±2.14 um, respectively) than in the DM + INS (W0-14) or DM groups (55.5±2.81 or 51.5±2.64 um, respectively) (P<0.05), and the intraepidermal nerve fiber (IENF) density was significantly higher in the DM + INS (W0-28) and DM + INS (W15-28) groups (6.9±0.46 and 6.8±0.11, respectively) than in the DM + INS (W0-14) or DM groups (59.5±0.32 and 5.3±0.39/mm, respectively) (P<0.05).

CONCLUSION

Our results indicate that continuous glucose control is necessary to alleviate peripheral nerve damage and that glycemic control during the later period may be more important than early period management. The importance of continuous glucose control, including the later period of diabetes, should therefore be emphasized in diabetic peripheral neuropathy.

Morphological comparison of small nerve fibres in gastric mucosa in non-diabetic and Type 2 diabetic subjects

AIM

To determine changes in small nerve fibres in gastric mucosa in patients with Type 2 diabetes by morphological observation.

METHODS

In twenty-five non-diabetic and 21 Type 2 diabetic participants, gastric mucosal biopsy under endoscopy was performed. Innervation in gastric mucosa was detected using immunohistochemical staining. Anti-protein gene product (PGP) 9.5 positive nerves underwent morphological observation and quantitative analysis.

RESULTS

Small nerve fibres in gastric mucosa were shortened in the diabetic subjects. The ratio of gastric mucosal protrusions maintaining nerve fibres between gastric pits to total observed protrusions was lower in patients with Type 2 diabetes compared with the non-diabetic subjects (ratio of innervated protrusion/total protrusion: 0.49 +/- 0.12 vs. 0.89 +/- 0.06, P < 0.05).

CONCLUSIONS

This study sets the scene for further research to investigate the relationship between gastric mucosal nerves and autonomic neuropathy or diabetic peripheral neuropathy.

The effect of alpha-lipoic acid on symptoms and skin blood flow in diabetic neuropathy

AIMS

Multiple pathogenic pathways are involved in diabetic neuropathy and diverse treatments have been tried without success. The aim of this study was to assess the effect of alpha-lipoic acid on skin blood flow in patients with diabetic neuropathy.

METHODS

We measured skin blood flow in 13 control subjects and 19 patients with diabetic neuropathy using the laser Doppler blood flow technique. Skin blood flow and the extent of skin blood flow changes were compared before and after diabetic patients received 600 mg/day alpha-lipoic acid intravenously for 14 days.

RESULTS

Although no significant differences in absolute values of skin blood flow or in the extent of changes were noted, symptoms were reduced after alpha-lipoic acid treatment.

CONCLUSIONS

This study suggests that alpha-lipoic acid, a potent antioxidant, improves symptoms of diabetic neuropathy. Larger studies are needed to determine whether improvements in skin blood flow also occur in patients with diabetic neuropathy.

Prevalence of and risk factors for extracranial internal carotid artery stenosis in Korean Type 2 diabetic patients

AIMS

The objectives of this study were to evaluate the prevalence of and risk factors for extracranial internal carotid artery stenosis in Type 2 diabetic patients.

METHODS

This study included 406 patients aged 40-79 years with Type 2 diabetes (male 55.4%, female 44.6%). Both carotid arteries of each patient were examined by carotid duplex scanning. The duplex ultrasound criteria based on the North American Symptomatic Carotid Endarterectomy Trial (NASCET) measurement method were used for the identification of carotid stenosis.

RESULTS

Extracranial internal carotid artery stenosis >or= 40% by velocity criteria was detected in 5.2% of the patients. The prevalence of carotid stenosis increased with advancing age: 1.0% at 40-49 years of age, 5.0% at 50-59 years, 7.3% at 60-69 years and 9.5% at 70-79 years. The degree of stenosis was > 70% in 42.9% of patients with stenosis, Bilateral stenosis was detected in 14% of patients. Of the patients with >or= 40% carotid stenosis, 33% had a decreased ankle-brachial index, 38% had a previous history of stroke, and only one patient (5%) had a documented history of coronary artery disease. Multivariate analysis, including variables determined to be significantly different by univariate analysis between patients with or without >or= 40% stenosis, indicated that age, systolic blood pressure and high-density lipoprotein (HDL)-cholesterol (inverse correlation) were independent risk factors associated with carotid stenosis.

CONCLUSIONS

Carotid duplex scanning is a useful strategy in identifying carotid stenosis in older Type 2 diabetic patients with high systolic blood pressure, or low levels of HDL cholesterol. The early identification and subsequent appropriate management of carotid stenosis, particularly in this group of patients, may facilitate efforts to reduce the incidence of macrovascular complications.

Parathyroid hormone (1-34) augments angiopoietin-1 expression in human osteoblast-like cells

Parathyroid hormone (PTH) is a major regulatory factor in skeletal physiology. However, the molecular mechanism underlying the effects of PTH on bones has yet to be elucidated in detail. Recently, some reports have demonstrated the crucial role of bone vasculature with regard to bone density. Angiopoietin-1 (Ang-1), along with VEGF, has been established as a primary angiogenic regulatory agent. In this study, we have attempted to characterize the effects of PTH (1-34) on Ang-1 expression and signaling molecules, employing primary-cultured human osteoblast-like cells. Quiescent osteoblasts were exposed to PTH (1-34), after which Ang-1 expression was determined at the mRNA and protein levels. Reverse transcription-polymerase chain reaction (RT-PCR) analyses indicated that Ang-1 mRNA expression increased as the result of PTH (1-34) treatment. The expression of the Ang-1 protein was also augmented as the result of treatment with PTH (1-34). An adenylyl cyclase activator, forskolin, was shown to induce Ang-1 mRNA expression, whereas the protein kinase A inhibitor, H-89, blocked the PTH (1-34)-mediated expression of Ang-1 mRNA. These findings indicate that PTH (1-34)-mediated Ang-1 expression involves adenylyl cyclase-protein kinase A dependent signaling. Our observations also show that Ang-1 may perform a crucial role in the effects of PTH (1-34) on bones, possibly involving alterations in bone vasculature.

Can diabetic neuropathy be prevented?

The incidence of diabetes and its complication have rapidly increased. Decreased quality of life and increased mortality are the major problems of people with diabetes. These problems are mainly caused by chronic complications. The incidence of diabetic neuropathy, which is one of these chronic complications, approaches 50% in most diabetic patients. The intensive metabolic management alone cannot completely prevent the development and progression of diabetic complications. Therefore, blocking and management of pathogenic mechanism of complication are required. Pathogenesis of diabetic neuropathy has multifactorial causes. Diabetic neuropathy is thought to occur both from direct hyperglycemia-induced damage to the nerve parenchyma and from neuronal ischemia brought about indirectly by hyperglycemia-induced decreases in neurovascular flow. The effects of hyperglycemia get converted to neuronal dysfunction via at least three secondary biochemical pathways: the polyol pathway, non-enzymatic glycation of proteins, oxidative stress and protein kinase C, and the interactions between them. Because of these interactions, interference with one of these biochemical pathways could either worsen or attenuate the effects of the others. So, the use of therapeutic intervention of these pathways is inevitable and valid to prevent the progression of diabetic neuropathy. As yet, a satisfactory and fundamental, preventive, and therapeutic method is not available with us to prevent progression. So, we will introduce the earlier diagnostic methods of diabetic neuropathy and will discuss the advantages and limitations of each method.

Hypoxia decreases Runx2/Cbfa1 expression in human osteoblast-like cells

To elucidate the molecular mechanism in relation to vascular supply and osteoporosis, we investigated the effect of hypoxia on Runx2 expression in MG63 cells. Also investigated was expression of type I collagen and osteocalcin, which are regulated by Runx2, alkaline phosphatase (ALPase) to see if they are affected by hypoxia. Quiescent cultures of MG63 cells were exposed to hypoxia (2% O(2)) and normoxia (18% O(2)) for 24, 48, 72 and 96 h. In cells exposed to hypoxia, reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that mRNA expression of Runx2, type I collagen, osteocalcin, and ALPase were decreased in a time dependent manner to 96 h. Activity of ALPase was also reduced in the same manner. Western blotting showed a marked decrease in Runx2 protein at 96 h in cells under hypoxia compared to normoxia. These data indicate that Runx2 expression in osteoblasts is reduced by hypoxia, and may be a mechanism of osteoporosis by decreased vascular supply.

Recurrent pseudotumor cerebri in systemic lupus erythematosus: a case report

Pseudotumor cerebri is an uncommon manifestation of neuropsychiatric systemic lupus erythematosus (SLE), and is characterized by an elevated intracranial pressure, papilledema with occasional abducens nerve paresis, absence of a space-occupying lesion or ventricular enlargement, and normal cerebrospinal fluid chemical and hematological constituents. Pseudotumor cerebri has been reported in a few sporadic cases in patients with systemic lupus erythematosus. However, the recurrent pseudotumor cerebri in patients with systemic lupus erythematosus which has been rarely reported, has not been reported in Korea. We experienced a 30-yr-old female patient with SLE who was presented with second attack of severe intractable headache. She was diagnosed pseudotumor cerebri twice and successfully treated with corticosteroid. Headache is the common symptom in patients with neuropsychiatric SLE and attributable to various causes. We suggest that it is important to define the cause of headache in patients with SLE and pseudotumor cerebri should be included in the spectrum of clinical manifestations during the course of SLE as a cause of headache.

Case report: diabetic muscle infarction presenting as knee arthralgia

Diabetic muscle infarction is a rare complication of diabetes and has characteristic clinical features including acute onset of pain with painful swelling, most commonly in the thigh or calf muscle, which gradually improves to complete resolution. Recently we experienced a case of diabetic muscular infarction presenting as knee joint pain due to involvement of the proximal portion of the leg muscle, which site has not been reported previously. This case shows that diabetic muscle infarction may involve sites other than the thigh and calf areas and should be considered in the differential diagnosis of knee arthralgia.

Mediastinal mass and brachial plexopathy caused by subclavian arterial aneurysm in Behçet's disease

Vascular involvement in Behçet's disease is divided into venous and arterial thrombosis and arterial aneurysmal formation. Subclavian arterial aneurysm rarely occurs in Behçet's disease; however, when it does occur, it causes serious aneurysmal rupture and local complications such as nerve compression and arterial ischemia. We describe the case of a 39-year-old male who presented with neurologic symptoms and signs of brachial plexopathy and mediastinal mass caused by Behçet's subclavian arterial aneurysm. This case shows that the occurrence of brachial plexopathy should be considered a manifestation of Behçet's disease, and that Behçet's aneurysm should be considered in the differential diagnosis of upper mediastinal mass.

A case of Sweet's syndrome in patient with dermatomyositis

Sweet's syndrome (SS) has been reported as an association with malignant neoplasms and autoimmune diseases, e.g., Behçet's disease, Sjogren's syndrome, and rheumatoid arthritis. But dermatomyositis (DM), one of the rare autoimmune diseases, was not reported as an associated disease of SS. We describe an interesting case of SS associated with DM. Diagnosis was made by skin biopsy, and subsequent clinical resolution occurred after institution of prednisolone.

Possible role of macrophage-derived soluble mediators in the pathogenesis of encephalomyocarditis virus-induced diabetes in mice

Pancreatic islets from DBA/2 mice infected with the D variant of encephalomyocarditis (EMC-D) virus revealed lymphocytic infiltration with moderate to severe destruction of pancreatic beta cells. Our previous studies showed that the major population of infiltrating cells at the early stages of infection is macrophages. The inactivation of macrophages prior to viral infection resulted in the prevention of diabetes, whereas activation of macrophages prior to viral infection resulted in the enhancement of beta-cell destruction. This investigation was initiated to determine whether macrophage-produced soluble mediators play a role in the destruction of pancreatic beta cells in mice infected with a low dose of EMC-D virus. When we examined the expression of the soluble mediators interleukin-1 beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), and inducible nitric oxide synthase (iNOS) in the pancreatic islets, we found that these mediators were clearly expressed at an early stage of insulitis and that this expression was evident until the development of diabetes. We confirmed the expression of these mediators by in situ hybridization with digoxigenin-labelled RNA probes or immunohistochemistry in the pancreatic islets. Mice treated with antibody against IL-1beta or TNF-alpha or with the iNOS inhibitor aminoguanidine exhibited a significant decrease in the incidence of diabetes. Mice treated with a combination of anti-IL-1beta antibody, anti-TNF-alpha antibody, and aminoguanidine exhibited a greater decrease in the incidence of disease than did mice treated with one of the antibodies or aminoguanidine. On the basis of these observations, we conclude that macrophage-produced soluble mediators play an important role in the destruction of pancreatic beta cells, resulting in the development of diabetes in mice infected with a low dose of EMC-D virus.

Changes of atrial natriuretic peptide level in patients with nephrotic syndrome after supine bicycle exercise

OBJECTIVES

The exact role of atrial natriutetic peptide (ANP) in the pathogenesis of edema in nephrotic syndrome (NS) has not been fully elucidated. We aimed to investigate the possible contribution of ANP to edema formation in NS.

METHODS

We subjected 18 nephrotic subjects and 20 healthy volunteers to supine bicycle exercise (SBE), a maneuver that seemed to increase venous return and to enhance the release of ANP. Plasma concentrations of immunoreactive-ANP were measured before and after SBE by radioimmunoassay.

RESULTS

There was a significant rise in the plasma concentration of ANP in the controls after SBE (from 31.1 +/- 6.16 to 42.0 +/- 6.01 pg/ml: p < 0.05). Meanwhile, there was no change in plasma concentration of ANP in the patients with NS (from 35.4 +/- 6.04 to 35.1 +/- 5.31 pg/ml). The change in plasma concentration of ANP in controls was significantly different from that in those with NS (p < 0.05). The mean baseline value of ANP in controls was the same as in NS.

CONCLUSIONS

These results show that SBE was a simple maneuver to stimulate the release of ANP in healthy controls. In contrast, it failed to stimulate the release of ANP in subjects with NS.

Cockayne syndrome: a case with hyperinsulinemia and growth hormone deficiency

Cockayne syndrome is a rare autosomal recessive disorder of childhood characterized by cachectic dwarfism with senile-like appearance, mental retardation, photosensitive dermatitis, loss of adipose tissue, pigmentary degeneration of retina, microcephaly, deafness, skeletal and neurologic abnormalities. We describe here an 18 year old boy with Cockayne syndrome who had, in addition to the typical features of the disorder, fasting hyperinsulinemia and growth hormone deficiency.

Induction of an organ-specific autoimmune disease, lymphocytic hypophysitis, in hamsters by recombinant rubella virus glycoprotein and prevention of disease by neonatal thymectomy

Glycosylated, membrane-associated E1 (58-kDa) and E2 (47- to 49-kDa) rubella virus proteins and unglycosylated nucleoprotein C (33 kDa), from separately expressed vaccinia virus recombinants, were injected into golden Syrian hamsters. Rubella virus E1 and E2 glycoproteins consistently induced an organ-specific autoimmune disease, autoimmune lymphocytic hypophysitis, which was evidenced by the induction of autoantibodies against pituitary cells and by lymphocytic infiltration of the pituitary. Neonatal thymectomy prevented the disease. In contrast, rubella virus nucleoprotein C did not induce either autoantibodies against pituitary cells or lymphocytic infiltration of the pituitary. This finding raises the possibility that virus-specific protein itself can induce an organ-specific autoimmune disease in certain circumstances.

Direct involvement of macrophages in destruction of beta-cells leading to development of diabetes in virus-infected mice

A single administration of complete Freund's adjuvant (CFA), type 1 carrageenan (Car), or silica 7, 2, and 2 days, respectively, before infection with a low dose (1 x 10(2) plaque-forming units/mouse) of encephalomyocarditis D (EMC-D) virus resulted in a significant increase in the incidence of diabetes in SJL/J mice (100%) compared with untreated EMC-D virus-infected mice (40%). Peritoneal macrophages were isolated from uninfected SJL/J mice, which had been treated once with silica, and transferred into SJL/J mice 2 days before low-dose EMC-D infection. Approximately 90% of the mice became diabetic, whereas 30% of mice that received virus alone became diabetic. The depletion of macrophages by treatment with the combined anti-Mac-1 and anti-Mac-2 monoclonal antibodies after a single administration of CFA, Car, or silica resulted in almost complete prevention of beta-cell destruction in EMC-D virus-infected mice. Furthermore, none of the mice in which macrophages were depleted by long-term treatment with silica and 10% of the mice treated with Car before virus infection became diabetic. On the basis of these observations, we conclude that macrophages are directly involved in the destruction of beta-cells, leading to the development of clinical diabetes in EMC-D virus-infected mice.

Role of macrophages in the pathogenesis of encephalomyocarditis virus-induced diabetes in mice

Pancreatic islets from SJL/J mice infected with the D variant of encephalomyocarditis virus (EMC-D virus) showed lymphocytic infiltration with moderate to severe destruction of beta cells. Immunohistochemical staining of the islet sections with several monoclonal antibodies, anti-Mac-1, anti-Mac-2, and F4/80 for macrophages, anti-L3T4 for helper/inducer T cells, and anti-Lyt2 for cytotoxic/suppressor T cells revealed that the major population of infiltrating cells at the early stage of viral infection was Mac-2-positive macrophages. In contrast, macrophages detected by anti-Mac-1 and F4/80 monoclonal antibodies were not found at the early stage of viral infection but were found at intermediate and late stages of viral infection. Helper/inducer T cells and cytotoxic/suppressor T cells also infiltrated the islets at intermediate and late stages of viral infection. Short-term treatment of mice with silica prior to viral infection resulted in an enhancement of beta-cell destruction, leading to the development of diabetes. In contrast, long-term treatment of mice with silica resulted in complete prevention of diabetes caused by a low dose of viral infection and a significant decrease in the incidence of diabetes caused by an intermediate or high dose of viral infection. Furthermore, depletion of macrophages by a specific monoclonal antibody (anti-Mac-2) resulted in a much greater decrease in the incidence of diabetes caused by an intermediate dose of viral infection. However, suppression of helper/inducer T cells and cytotoxic/suppressor T cells, by anti-L3T4 and anti-Lyt2 antibodies, respectively, did not alter the incidence of diabetes. On the basis of these data, it is concluded that macrophages, particularly Mac-2-positive macrophages, play a crucial role in the process of pancreatic beta-cell destruction at the early stage of encephalomyocarditis D virus infection in SJL/J mice.