Metformin treatment is associated with an increase in bone mineral density in type 2 diabetes mellitus patients in China: a retrospective single center study

AIMS

- To investigate the association between metformin and bone mineral density (BMD) in a large cohort of Chinese patients with type 2 diabetes mellitus (T2DM).

METHODS

- A total of 11,458 T2DM patients aged ≥ 40 years were included. Information on demographic, anthropometric and clinical characteristics was collected from medical records. BMD at lumbar spine (LS), femoral neck (FN), and total hip(TH) was assessed by dual-energy X-ray absorptiometry.

RESULTS

- Overall prevalence of osteopenia and osteoporosis was 37.4% and 10.3%, and was lower in patients on metformin (34.6% vs 38.3% and 7.1% vs 11.3%, both P < 0.001). Patients who had a lower BMI, older age, and lower estimated glomerular filtration rate (eGFR), had more osteoporosis, lower BMD (osteoporosis or osteopenia), and a lower T-score at LS, FN and TH. Metformin use and male sex was associated with a higher BMD. Metformin treatment was also independently associated with higher T-score at LS, FN and TH (β values of 0.120, 0.082 and 0.108; all P < 0.001), and lower odds ratio of osteoporosis (OR = 0.779, 95%CI: 0.648-0.937, P = 0.008) or low BMD (OR = 0.834, 95%CI: 0.752 - 0.925, P = 0.001). However, when analyzed by sex, this association of a lower odds ratio for osteoporosis with metformin was only significant in women (OR= 0.775, 95% CI: 0.633-0.948; P = 0.013).

CONCLUSIONS

- Metformin treatment was associated with a higher T-score and a lower odds ratio of osteopenia and osteoporosis, especially in the female population, independent of age, BMI, and eGFR.

First use of gene therapy to treat growth hormone resistant dwarfism in a mouse model

The only treatment tested for growth hormone receptor (GHR) defective Laron Syndrome (LS) is injections of recombinant insulin-like-growth factor 1 (rhIGF1). The response is suboptimal and associated with progressive obesity. In this study, we treated 4–5-week-old Laron dwarf mice (GHR−/−) with an adeno-associated virus expressing murine GHR (AAV-GHR) injection at a dose of 4 × 10¹⁰ vector genome per mouse. Serum growth hormone (GH) levels decreased, and GH-responsive IGF1, IGF binding protein 3 (IGFBP3) and acid labile subunit (ALS) increased. There was a significant but limited increase in body weight and length, similar to the response to rhIGF1 treatment in LS patients. All the major organs increased in weight except the brain. Our study is the first to use gene therapy to treat GH-receptor deficiency. We propose that gene therapy with AAV-GHR may eventually be useful for the treatment of human LS.

Association of decreased sperm motility and increased seminal plasma IGF-I, IGF-II, IGFBP-2, and PSA levels in infertile men

PURPOSE

Previous studies have suggested the involvement of serum insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) in the regulation of the female reproductive system. Little is known of these peptides in the seminal plasma (SP) of men and their potential effects on fertility. We assessed SP levels of these peptides in infertile men with low sperm motility (asthenozoospermic; AZ) and low sperm counts (oligozoospermic; OZ), its effects on in vivo sperm motility, and whether there is a correlation with aging.

METHODS

Twenty-eight infertile men (AZ; n = 18 and OZ; n = 10) and 20 fertile normozoospermic (NZ) men were studied. Seminal plasma IGF-I, IGF-II, IGFBP-2, IGFBP-3, and prostate-specific antigen (PSA) levels were measured, and spermatozoa mRNA transcript patterns were examined.

RESULTS

Asthenozoospermic men had higher SP IGF-I, IGF-II, IGFBP-2, and PSA levels than NZ and OZ men, whereas SP IGFBP-3 levels were similar between the three groups. Sperm count positively correlated with SP IGF-I, IGF-II, and IGFBP-2; sperm motility negatively correlated with SP IGF-II and IGFBP-2; and age correlated positively with SP IGF-II. The expression of IGF-I and IGF-II mRNA and mRNA receptors was detectable, but no variations in transcript levels were noted.

CONCLUSION

Decreased sperm motility, but not sperm count, in infertile AZ men is associated with increased SP IGF-I, IGF-II, IGFBP-2, and PSA levels. Changes in SP IGFs and their interactions with IGFBPs and IGF receptors, and PSA levels suggest a role of these SP peptides in modulating sperm motility and possibly prostate disease development in aging men.

Progressive endoplasmic reticulum stress over time due to human insulin gene mutation contributes to pancreatic beta cell dysfunction

AIMS/HYPOTHESIS

We studied the effects of heterozygous human INS gene mutations on insulin secretion, endoplasmic reticulum (ER) stress and other mechanisms in both MIN6 and human induced pluripotent stem cells (hiPSC)-derived beta-like cells, as well as the effects of prolonged overexpression of mutant human INS in MIN6 cells.

METHODS

We modelled the structure of mutant C109Y and G32V proinsulin computationally to examine the in silico effects. We then overexpressed either wild-type (WT), mutant (C109Y or G32V), or both WT and mutant human preproinsulin in MIN6 cells, both transiently and stably over several weeks. We measured the levels of human and rodent insulin secreted, and examined the transcript and protein levels of several ER stress and apoptotic markers. We also reprogrammed human donor fibroblasts heterozygous for the C109Y mutation into hiPSCs and differentiated these into pancreatic beta-like cells, which were subjected to single-cell RNA-sequencing and transcript and protein analyses for ER stress and apoptotic markers.

RESULTS

The computational modelling studies, and short-term and long-term expression studies in beta cells, revealed the presence of ER stress, organelle changes and insulin processing defects, resulting in a decreased amount of insulin secreted but not the ability to secrete insulin. By 9 weeks of expression of mutant human INS, dominant-negative effects of mutant INS were evident and beta cell insulin secretory capacity declined. INS^+/C109Y patient-derived beta-like cells and single-cell RNA-sequencing analyses then revealed compensatory upregulation in genes involved in insulin secretion, processing and inflammatory response.

CONCLUSIONS/INTERPRETATION

The results provide deeper insights into the mechanisms of beta cell failure during INS mutation-mediated diabetes disease progression. Decreasing spliced X-box binding protein 1 (sXBP1) or inflammatory response could be avenues to restore the function of the remaining WT INS allele.

Modification of a Constitutive to Glucose-Responsive Liver-Specific Promoter Resulted in Increased Efficacy of Adeno-Associated Virus Serotype 8-Insulin Gene Therapy of Diabetic Mice

We have previously used a hepatotropic adeno-associated viral (AAV) vector with a modified human insulin gene to treat diabetic mice. The HLP (hybrid liver-specific promoter) used was constitutively active and non-responsive to glucose. In this study, we examined the effects of addition of glucose responsive elements (R3G) and incorporation of a 3' albumin enhancer (3'iALB) on insulin expression. In comparison with the original promoter, glucose responsiveness was only observed in the modified promoters in vitro with a 36 h lag time before the peak expression. A 50% decrease in the number of viral particles at 5 × 10⁹ vector genome (vg)/mouse was required by AAV8-R3GHLP-hINSco to reduce the blood sugar level to near normoglycemia when compared to the original AAV8-HLP-hINSco that needed 1 × 10¹⁰ vg/mouse. The further inclusion of an 860 base-pairs 3'iALB enhancer component in the 3' untranslated region increased the in vitro gene expression significantly but this increase was not observed when the packaged virus was systemically injected in vivo. The addition of R3G to the HLP promoter in the AAV8-human insulin vector increased the insulin expression and secretion, thereby lowering the required dosage for basal insulin treatment. This in turn reduces the risk of liver toxicity and cost of vector production.

Efficacy and safety of pulsed intravenous methylprednisolone in early active thyroid eye disease

Introduction: The mainstay of therapy for active inflammatory phase of thyroid eye disease (TED) is immunosuppression. Patients in our centre with early active TED are treated with pulsed intravenous methylprednisolone (IVMP). Two different protocols are offered in our centre: High dose (1g/day for 3 days, monthly for 6 months), or EUGOGO protocol (500 mg weekly for six weeks, followed by 250 mg weekly for the next 6 weeks). Methods: A prospective cohort study of patients undergoing the two IVMP protocols was performed from January 2009 to May 2015. Main outcome measures were improvement of Clinical Activity Score (CAS) and International Thyroid Eye Disease (ITEDS) - VISA Inflammatory Index. Results: We had a total of 63 patients. Mean age was 43.1 ± 13.1years, females comprised 49.2% (n = 31), and 31 (49.2%) had a positive smoking history. Following IVMP, 65.0% (n = 41) had good response, 31.7% (n = 20) partial, and 3.3% (n = 2) poor. There were significant differences (p < 0.001) in CAS and ITEDS scores between pre-IVMP and post-IVMP visits, for both protocols. A higher proportion of patients receiving the modified EUGOGO protocol (58.3%) had persistent activity and required additional immunosuppression compared to those who underwent the high dose protocol (33.3%). Mild side effects were experienced by 5 (7.9%) and 3 (4.8%) patients at 3 and 6 months, respectively. There were no severe side effects, cardiovascular events or liver failure. Conclusion: With adequate screening and follow-up, six repeated cycles of high dose pulsed IVMP is an effective treatment for TED and can significantly reduce the morbidity associated with this debilitating condition. None of the 51 patients from the high dose protocol met with any serious side effects.

Immunosuppression overcomes insulin- and vector-specific immune responses that limit efficacy of AAV2/8-mediated insulin gene therapy in NOD mice

We report the restoration of euglycaemia in chemically induced diabetic C57BL/6 mice and spontaneously diabetic Non Obese Diabetic (NOD) mice by intravenous systemic administration of a single-stranded adeno-associated virus (ssAAV2/8) codon optimised (co) vector encoding furin cleavable human proinsulin under a liver-specific promoter. There were no immunological barriers to efficacy of insulin gene therapy in chemically induced C57BL/6 mice, which enjoyed long-lasting correction of hyperglycaemia after therapy, up to 250 days. Euglycaemia was also restored in spontaneously diabetic NOD mice, although these mice required a 7-10-fold higher dose of vector to achieve similar efficacy as the C57BL/6 mice and the immunodeficient NODscid mice. We detected CD8+ T cell reactivity to insulin and mild inflammatory infiltration in the livers of gene therapy recipient NOD mice, neither of which were observed in the treated C57BL/6 mice. Efficacy of the gene therapy in NOD mice was partially improved by targeting the immune system with anti-CD4 antibody treatment, while transfer of NOD mouse AAV2/8-reactive serum to recipients prevented successful restoration of euglycaemia in AAV2/8-HLP-hINSco-treated NODscid mice. Our data indicate that both immune cells and antibodies form a barrier to successful restoration of euglycaemia in autoimmune diabetic recipient mice with insulin gene therapy, but that this barrier can be overcome by increasing the dose of vector and by suppressing immune responses.

Development of a liver-specific Tet-off AAV8 vector for improved safety of insulin gene therapy for diabetes

Background

Diabetes mellitus is caused by a partial or complete lack of insulin production in the body. We have previously shown that a single injection of an adeno‐associated virus serotype 8 (AAV8) vector carrying a modified and codon optimized human insulin gene induced hepatic production of insulin and corrected streptozotocin (STZ)‐induced diabetes in mice for more than 1 year. Insulin production was constitutive, analogous to long‐acting insulin therapy.

Methods

We have developed a single AAV8 vector with a Tet‐Off regulatable system as a safety mechanism to turn off insulin secretion should hypoglycaemia develop in vector‐treated diabetic mice. We first transfected HepG2 cells or freshly isolated rat hepatocytes in vitro with the Tet‐Off system (pAAV‐Tetoff_bidir‐Alb‐luc) regulating a luciferase reporter gene. We subsequently incorporated a furin‐cleavable codon‐optimised human proinsulin cDNA into pAAV‐Tetoff_bidir backbone to form the doxycycline inducible pAAV‐Tetoff_bidir‐Alb‐hINSco.

Results

Using STZ‐induced diabetic mice, we were able to switch off insulin secretion repeatedly with doxycycline administration, and showed full restoration of insulin secretion on withdrawing doxycycline.

Conclusions

The present study provides proof of concept that, under circumstances when inappropriate basal insulin secretion is a safety concern, insulin secretion from AAV8 gene therapy can be turned off reversibly with doxycycline.

Contributions of Fasting and Postprandial Glucose Concentrations to Haemoglobin A1c in Drug-Naïve Mal-Glucose Metabolism in Chinese Population Using Continuous Glucose Monitoring System

AIM

To clarify the contributions of fasting glucose (FG) and postprandial glucose (PG) to HbA1c in drug-naïve patients with type 2 diabetes (T2D) and impaired glucose tolerate (IGT)/impaired fasting glucose (IFG).

METHODS

Continuous glucose monitoring (CGM) was performed in 305 drug-naïve Chinese patients with T2D or IGT/IFG. The incremental area under the curve (AUC) above a glucose value of 6.1 mmol/L or FG glucose levels were calculated to evaluate the contributions of PG or FG to HbA1c values.

RESULTS

According to quintiles of HbA1c, T2D patients were divided into five groups (group 1 to 5), and patients with IGT/IFG were assigned into group 0. PG was the predominant contributor in the lower groups with HbA1c 4.9∼6.0% and 6.1∼7.8%. The relative contributions of FG and PG to HbA1c had no significance in the middle groups of HbA1c (7.9∼8.7% and 8.8∼9.5%). FG contributed significantly more than PG in the higher groups of HbA1c (9.6∼10.9% and 11.0∼14.6%). Regression analyses indicate that the contributions of FG and PG were equal (both 50%) when the level of HbA1c was 8.5%.

CONCLUSIONS

In drug-naïve patients with T2D or IGT/IFG, PG contributed more in patients with HbA1c < 8.5%, whereas FG became the predominant contributor in the poorly controlled patients with HbA1c ≥ 8.5%. These results may help the health-care provider set appropriate plasma glucose testing goals with the expectation of achieving specific HbA1c values.

A comparison of clinical efficacy and economic value in Basalin- and Lantus-treated patients with type 2 diabetes using continuous glucose monitoring system

AIM

To determine the clinical non-inferiority of recombinant glargine-Basalin vs glargine-Lantus, in treatment of type 2 diabetes mellitus (T2DM) using continuous glucose monitoring system (CGMS).

METHODS

One hundred patients with T2DM were recruited. They were either regularly taking Basalin (Basalin group) or Lantus (Lantus group) (n = 50 each). CGMS was employed to real-time monitor blood glucose profile for 4 days (from day 1 to day 5). To exclude the effect of patient background, the study design was to have a blinded crossover from glargine-Basalin to glargine-Lantus on day 3, and vice versa. 24-hour mean blood glucose (24hMBG), 24-hour standard deviation of blood glucose (24hSDBG), 24-hour mean amplitude of glycemic excursion (24hMAGE), and number of glycemic excursion (NGE) every 24 h (24hNGE) were calculated for each glargine from 100 patients.

RESULTS

No significant difference of 24hMBG, 24hSDBG, 24hMAGE, and 24hNGE (p > 0.05 for all) was found between Basalin and Lantus treatments. The glucose area under the curve and time when blood glucose was below 3.9 mmol/L, between 3.9 and 10.0 mmol/L, or above 10.0 mmol/L were similar between Basalin and Lantus treatment. The frequency of hypoglycemic episodes was also similar. However, the mean cost of Basalin was only 72% of Lantus's in one treatment course.

CONCLUSION

Glargine-Basalin is non-inferior in clinical efficacy compared to glargine-Lantus. In view of the large difference in the cost of glargine-Basalin, it would be much more cost-effective for our patients.

Relationship between Thyroid Function and Kidney Function in Patients with Type 2 Diabetes

PURPOSE

To determine if the TSH is related to estimated glomerular filtration rate (eGFR) in T2D patients without overt thyroid dysfunction.

METHODS

A cohort study of 5936 T2D patients was assessed for thyroid and kidney functions, in whom 248 with subclinical hyperthyroidism and 362 with subclinical hypothyroidism. Serum creatinine and 24-hour urine albumin excretion (UAE) were collected. Chronic kidney disease (CKD) was defined as eGFR < 60 ml/min/1.73 m².

RESULTS

Compared with euthyroid subjects, the patients with subclinical hypothyroidism had lower eGFR (82.7 ± 22.4 vs. 90.5 ± 22.4 ml/min/1.73 m², p < 0.01), higher UAE (114 ± 278 vs. 88 ± 229 mg/24 h, p < 0.05), and high incidence of CKD (16.0% vs. 10.1%, p < 0.05). The participants with a TSH level between 0.55 and 3.0 μIU/ml had a higher eGFR (91.4 ± 22.2 ml/min/1.73 m²) and a lower prevalence of CKD (9.5%) than those with higher TSH (3.01-4.78 μIU/ml, 85.6 ± 22.7 ml/min/1.73 m², p < 0.01 and 13.1%, p < 0.01). Linear logistic regression analysis showed that the eGFR was significantly negatively associated with TSH (OR: 0.519, 95% CI: 0.291-0.927, p < 0.05), after adjustment of confounders.

CONCLUSION

High TSH was independently associated with decreased eGFR in type 2 diabetes patients without overt thyroid dysfunction. Our findings indicate that doctors who treat T2D patients should routinely measure the thyroid function.

Use of cabergoline for the management of persistent Cushing's disease in pregnancy

Cushing's disease (CD) is rare during pregnancy and is associated with significant maternal and fetal complications. It is important to control hypercortisolism during pregnancy, either surgically or medically, for a successful maternal and fetal outcome. We report a patient with recurrent CD who was treated with low-dose cabergoline (CAB) for persistent hypercortisolism throughout pregnancy. A 36-year-old woman was diagnosed with CD at the age of 23. She underwent trans-sphenoidal surgery with initial complete remission. However, 4 years after surgery, CD recurred and she underwent Gamma Knife radiosurgery (GKRS). Following GKRS, her cortisol levels remained elevated despite no evidence of visible tumour on pituitary MRI. Medical treatment was commenced with ketoconazole and cyproheptadine. This was changed to CAB as she was keen for pregnancy. She conceived spontaneously and was on CAB throughout pregnancy. She delivered a healthy male neonate, weighing 3195 g at 40 weeks of gestation.

Use of cabergoline for the management of persistent Cushing's disease in pregnancy

Cushing's disease (CD) is rare during pregnancy and is associated with significant maternal and fetal complications. It is important to control hypercortisolism during pregnancy, either surgically or medically, for a successful maternal and fetal outcome. We report a patient with recurrent CD who was treated with low-dose cabergoline (CAB) for persistent hypercortisolism throughout pregnancy. A 36-year-old woman was diagnosed with CD at the age of 23. She underwent trans-sphenoidal surgery with initial complete remission. However, 4 years after surgery, CD recurred and she underwent Gamma Knife radiosurgery (GKRS). Following GKRS, her cortisol levels remained elevated despite no evidence of visible tumour on pituitary MRI. Medical treatment was commenced with ketoconazole and cyproheptadine. This was changed to CAB as she was keen for pregnancy. She conceived spontaneously and was on CAB throughout pregnancy. She delivered a healthy male neonate, weighing 3195 g at 40 weeks of gestation.

Correction of Murine Diabetic Hyperglycaemia With A Single Systemic Administration of An AAV2/8 Vector Containing A Novel Codon Optimized Human Insulin Gene

We report the correction of hyperglycemia of STZ induced diabetic mice using one intravenous systemic administration of a single stranded serotype 8 pseudotyped adeno-associated virus (ssAAV2/8) vector encoding the human proinsulin gene under a constitutive liver specific promoter. In vivo dose titration experiments were carried out and we identified an optimal range that achieved maintenance of euglycaemia or a mild diabetic condition for at least 9 months and ongoing to beyond 1 year for some animals, accompanied by human C-peptide secretion and weight gain. Further DNA codon optimization of the insulin gene construct resulted in approximately 3-10 times more human C-peptide secreted in the blood of codon optimized treated animals thereby reducing the number of vector particles required to achieve the same extent of reduction in blood glucose levels as the non-codon optimized vector. The constitutive secretion of insulin achieved with a single administration of the vector could be of therapeutic value for some diabetic patients.

Growth Hormone Research Society perspective on the development of long-acting growth hormone preparations

OBJECTIVE

The Growth Hormone (GH) Research Society (GRS) convened a workshop to address important issues regarding trial design, efficacy, and safety of long-acting growth hormone preparations (LAGH).

PARTICIPANTS

A closed meeting of 55 international scientists with expertise in GH, including pediatric and adult endocrinologists, basic scientists, regulatory scientists, and participants from the pharmaceutical industry.

EVIDENCE

Current literature was reviewed for gaps in knowledge. Expert opinion was used to suggest studies required to address potential safety and efficacy issues.

CONSENSUS PROCESS

Following plenary presentations summarizing the literature, breakout groups discussed questions framed by the planning committee. Attendees reconvened after each breakout session to share group reports. A writing team compiled the breakout session reports into a draft document that was discussed and revised in an open forum on the concluding day. This was edited further and then circulated to attendees from academic institutions for review after the meeting. Participants from pharmaceutical companies did not participate in the planning, writing, or in the discussions and text revision on the final day of the workshop. Scientists from industry and regulatory agencies reviewed the manuscript to identify any factual errors.

CONCLUSIONS

LAGH compounds may represent an advance over daily GH injections because of increased convenience and differing phamacodynamic properties, providing the potential for improved adherence and outcomes. Better methods to assess adherence must be developed and validated. Long-term surveillance registries that include assessment of efficacy, cost-benefit, disease burden, quality of life, and safety are essential for understanding the impact of sustained exposure to LAGH preparations.

Liraglutide treatment causes upregulation of adiponectin and downregulation of resistin in Chinese type 2 diabetes

AIMS

To assess the effect of 16 weeks of liraglutide administration on the plasma levels of adiponectin and resistin in Chinese patients diagnosed with type 2 diabetes mellitus (T2DM).

METHODS

Forty-four subjects were recruited and randomly assigned to once-a-day dosage of either liraglutide, or glimepiride (4 mg) in a double-blinded double-dummy active-controlled study. All treatments were administered in combination with metformin (1 g, twice daily). The efficacy of liraglutide was estimated by measuring and comparing the levels of HbA1c, adiponectin and resistin in the plasma before and after the 16-week treatment.

RESULTS

The plasma level of adiponectin was significantly increased (0.74±0.19 ng/ml, p<0.05) and resistin was significantly lowered (-1.34±0.34 pg/ml, p<0.05) in a dose-dependent manner in the liraglutide group when compared with the glimepiride group (-0.44±0.09 ng/ml of adiponectin and 0.14±0.41 pg/ml of resistin). In contrast, we found no differences in the decrease in HbA1c between the two groups (8.3±1.2% to 7.2±1.1% in NGSP units vs. 8.3±1.0% to 7.3±1.2% in NGSP units; 67±13 mmol/mol to 55±12 mmol/mol vs. 67±11 mmol/mol to 56±13 mmol/mol in IFCC units).

CONCLUSIONS

In Chinese T2DM patients, liraglutide treatment led to increased adiponectin and decreased resistin levels compared to glimepiride-treated subjects, while inducing similar glycemic changes.

Characterization of Insulin-Secreting Porcine Bone Marrow Stromal Cells Ex Vivo and Autologous Cell Therapy in Vivo

Cell therapy could potentially meet the need for pancreas and islet transplantations in diabetes mellitus that far exceeds the number of available donors. Bone marrow stromal cells are widely used in clinical trials mainly for their immunomodulatory effects with a record of safety. However, less focus has been paid to developing these cells for insulin secretion by transfection. Although murine models of diabetes have been extensively used in gene and cell therapy research, few studies have shown efficacy in large preclinical animal models. Here we report optimized conditions for ex vivo expansion and characterization of porcine bone marrow stromal cells and their permissive expression of a transfected insulin gene. Our data show that these cells resemble human bone marrow stromal cells in surface antigen expression, are homogeneous, and can be reproducibly isolated from outbred Yorkshire–Landrace pigs. Porcine bone marrow stromal cells were efficiently expanded in vitro to >1010 cells from 20 ml of bone marrow and remained karyotypically normal during expansion. These cells were electroporated with an insulin expression plasmid vector with high efficiency and viability, and secreted human insulin and C-peptide indicating appropriate processing of proinsulin. We showed that autologous insulin-secreting bone marrow stromal cells implanted and engrafted in the liver of a streptozotocin-diabetic pig that modeled type 1 diabetes resulted in partial, but significant, improvement in hyperglycemia that could not be ascribed to regeneration of endogenous β-cells. Glucose-stimulated insulin secretion in vivo from implanted cells in the treated pig was documented by a rise in serum human C-peptide levels during intravenous glucose tolerance tests. Compared to a sham-treated control pig, this resulted in significantly reduced fasting hyperglycemia, a slower rise in serum fructosamine, and prevented weight loss. Taken together, this study suggests that bone marrow stromal cells merit further development as autologous cell therapy for diabetes.

Thyroid eye disease: a Southeast Asian experience

AIM

To study the demographics, comorbidities, clinical manifestations and treatment methods of thyroid eye disease (TED) in Singapore.

METHODS

In this retrospective case series, we analysed the case records of all patients with TED who presented at our multidisciplinary Thyroid Eye Clinic from November 2002 to October 2012.

RESULTS

There were a total of 174 patients-111 female patients (63.8%) and 63 male patients (36.2%). The majority of the patients were ethnically Chinese (80.5%), followed by Malay (10.3%) and Indian (6.3%). The mean age was 40.2 years (SD±15.5, range 0.3-87.0). The commonest sign on ophthalmic examination was eyelid retraction (62.1%), followed by proptosis (61.0%) and lid lag (57.5). Acquired epiblepharon and corneal erosions were noted in 11.5% and 29.3% respectively. Eight patients (4.6%) had dysthyroid optic neuropathy. The mean exophthalmometry reading was 18.8 mm (SD±3.32, range 10.0-28.0). Mild, moderate and severe disease was noted in 71.3%, 20.7% and 8.0% respectively. Thyroid dysfunction was managed with anti-thyroid medication only (40.2%), β blockers (19.5%), thyroxine replacement (14.4%), radioactive iodine (14.4%) and block-replace regime (9.8%). Clinically significant active orbitopathy was managed with intravenous corticosteroids (12.1%). Surgical procedures consisted of thyroidectomy (10.3%), eyelid surgery (8.6%), orbital decompression (7.5%), epiblepharon correction (2.3%) and strabismus surgery (0.6%).

CONCLUSIONS

Corneal erosion secondary to acquired epiblepharon is a common sign in East Asian patients with TED, thus increased awareness among physicians should be encouraged. Mean exophthalmometry values and frequencies of upper eyelid retraction and oedema are lower in East Asian patients compared with Caucasian patients. Among Singapore's multi-ethnic population, Malay patients with TED had the highest exophthalmometry reading.

Effect of oral N-acetyl cysteine supplementation in type 2 diabetic patients on intracellular glutathione content and innate immune responses to Burkholderia pseudomallei

Type 2 diabetic patients have increased susceptibility to melioidosis, an infectious disease caused by Burkholderia pseudomallei. We had previously shown that peripheral blood mononuclear cells (PBMCs) from diabetic patients with poor glycemic control had a defective IL-12 and IFNγ response to B. pseudomallei infection, resulting in poor intracellular bacterial control. The impaired IL-12 response was due to glutathione (GSH) deficiency characterized by a low reduced to oxidized glutathione ratio (GSH ratio) and could be restored by the addition of reduced GSH to the infected cells. Our goal is to determine whether N-acetyl cysteine (NAC, a GSH pro-drug) supplementation in diabetic patients could improve their immune control of B. pseudomallei. Type 2 diabetic patients with poor glycemic control were given oral supplementation of NAC for six weeks at 1200 mg daily. Their PBMCs and subsets of immune cells showed a significant increase in free GSH concentration. However, the GSH ratio, IL-12 and IFNγ production, and intracellular bacterial killing upon ex-vivo infection did not improve. Thus, oral NAC supplementation in diabetic patients is sufficient to increase intracellular GSH content in blood cells. However, modulating the free GSH content is not sufficient to improve infection outcome as it is the GSH ratio that regulates the IL-12 response in monocytes.

Visfatin and its genetic variants are associated with obesity-related morbidities and cardiometabolic risk in severely obese children

BACKGROUND

Visfatin is an adipokine, associated with obesity and possibly glucose regulation.

OBJECTIVE

The aim of this study was to examine the association of visfatin and its genetic variants with adiposity, cardiometabolic risk factors and obesity-related morbidities in obese children.

METHODS

Anthropometric measurements, dual energy X-ray absorptiometry scan, fasting blood samples and oral glucose tolerance tests were performed for 243 obese children. We screened the visfatin gene of 24 obese subjects and then performed genotyping of identified genetic variants in other 219 obese children through direct DNA sequencing.

RESULTS

Fasting serum visfatin correlated with measures of obesity and liver enzymes and was elevated in obese children with abnormal glucose tolerance and non-alcoholic fatty liver disease. The two upstream single nucleotide polymorphisms, -3187G>A (rs11977021) and -1537C>T (rs61330082), were at complete linkage disequilibrium. The AA genotype of -3187G>A was associated with higher serum visfatin (6.17 ± 0.76 ng mL(-1) vs. 3.92 ± 0.44 ng mL(-1)) and higher triglyceride (1.39 ± 0.08 mmol L(-1) vs. 1.19 ± 0.07 mmol L(-1)) as compared with the GG genotype. There was also a significant linear increase in serum visfatin across GG to GA to AA genotype of -3187G>A, indicating possible additive effect of A allele. The dominant GA + AA genotype model of +21426G>A (rs2302559) was associated with lower serum visfatin (3.83 ± 0.56 ng mL(-1) vs. 5.13 ± 0.34 ng mL(-1)) and lower plasma glucose (4.37 ± 0.08 mmol L(-1) vs. 4.77 ± 0.12 mmol L(-1)) as compared with the GG genotype.

CONCLUSION

Visfatin and its genetic variants were associated with adiposity, obesity-related morbidities and adverse cardiometabolic parameters. This supported our hypothesis that visfatin plays a significant role in the development of obesity-related morbidities and cardiometabolic risk.

Defining the expression hierarchy of latent T-cell epitopes in Epstein-Barr virus infection with TCR-like antibodies

Epstein-Barr virus (EBV) is a gamma herpesvirus that causes a life-long latent infection in human hosts. The latent gene products LMP1, LMP2A and EBNA1 are expressed by EBV-associated tumors and peptide epitopes derived from these can be targeted by CD8 Cytotoxic T-Lymphocyte (CTL) lines. Whilst CTL-based methodologies can be utilized to infer the presence of specific latent epitopes, they do not allow a direct visualization or quantitation of these epitopes. Here, we describe the characterization of three TCR-like monoclonal antibodies (mAbs) targeting the latent epitopes LMP1(125-133), LMP2A(426-434) or EBNA1(562-570) in association with HLA-A0201. These are employed to map the expression hierarchy of endogenously generated EBV epitopes. The dominance of EBNA1(562-570) in association with HLA-A0201 was consistently observed in cell lines and EBV-associated tumor biopsies. These data highlight the discordance between MHC-epitope density and frequencies of associated CTL with implications for cell-based immunotherapies and/or vaccines for EBV-associated disease.

Endocrine emergencies in pregnancy

Endocrine emergencies in pregnancy are rare and are more likely to occur in the absence of good obstetric care. Serious thyroid and diabetes related events in pregnancy are more common because of their higher prevalence in the normal population. Pituitary complications in pregnancy are now relatively rare. A high index of suspicion is needed for early diagnosis, and medical treatment is directed primarily at maintaining maternal hemodynamic stability. A close liaison between an endocrinologist, maternal-fetal specialist and intensivist is critical in optimising both maternal and fetal outcomes.

EMLA-Induced Skin Wrinkling for the Detection of Diabetic Neuropathy

Objective: To determine the usefulness of Eutectic Mixture of Local Anesthetic (EMLA)-induced stimulated skin wrinkling (SSW) to detect diabetic sensorimotor polyneuropathy (DSPN).

Research Design and Methods: Two hundred and ten diabetics were prospectively recruited (mean age 58.5 ± 12.7 years) from a large tertiary center from 2009 to 2011. EMLA was applied to the tips of digits 2, 3, and 4 and the degree of wrinkling graded. Diabetic Neuropathy Symptom (DNS) score, nerve conduction studies (NCS), Semmes–Weinstein monofilament (SWMF) tests, and vibratory perception thresholds (VPTs) testing were chosen as comparative clinical standards to diagnose length-dependent DSPN.

Results: Inter-rater agreement for two examiners of SSW was high, with Cohen’s weighted κ of 0.912 for the right hand, and 0.823 for the left. K measure of agreement of SSW with the NCS, DNS scores, SWMF testing, and VPT testing was 0.486, 0.243, 0.289, and 0.395 respectively. SSW was able to distinguish between normal and abnormal NCS and DNS results, with median scores of 3.333 vs. 1.667 (p < 0.0005); and 3.167 vs. 2.000 (p < 0.0005) respectively. Following receiver operating characteristic-analysis, at a cut-off point of <3 for an abnormal SSW test, sensitivity of SSW test for diagnosing DSPN using NCS as a reference standard was 81.3%, and specificity was 67.0%, on par with other testing methods.

Conclusion: SSW shows comparable sensitivity to other methods for detecting DSPN. Given its low cost and easy administration, SSW can be considered a useful alternative screening method for diagnosing diabetic neuropathy.

Gene and stem cell therapy for diabetes

Gene and stem cell therapy has been on the scientific agenda in many laboratories for more than 20 years. The literature is enormous, but practical applications have been few. Recently advances in stem cell biology and gene therapy are clarifying some of the issues. I have made a few observations concerning our own studies on bone marrow mesenchymal stem cells cultured to produce a small percentage of insulin-producing cells and human insulin gene engineered into Lenti and AA viruses. The aim of clinical application would still seem to be several years away, if all goes well. The first step will be to produce enough insulin-secreting cells to be of potential value to patients. The next crucial question will be how to persuade the cells to respond to blood glucose levels swiftly and appropriately. With both stem cell and gene therapy, another important factor will be to ensure that any positive results will continue long enough to be preferable to insulin injections.

The association of a nucleobindin 2 gene (NUCB2) variant with childhood adiposity

Nucleobindin 2 (NUCB2) is a precursor of nesfatin-1, a hypothalamic anorectic neuropeptide. The association between variants of the NUCB2 gene and adiposity was examined. 142 severely obese Chinese children in Singapore, and 384 normal weight Chinese children from a longitudinal cohort from Da Qing, China, were studied. NUCB2 was screened using PCR and direct sequencing in 29 severely obese children and 24 non-obese children, then screened for a variant c.1012C>G (Q338E, or rs757081) in the rest of the cohort using TaqMan probe. Five variants, including c.1012C>G (Q338E) were found. Genotyping for c.1012C>G found that the GG genotype was significantly less frequent in the obese group; odds ratio for obese subjects carrying the CC and CG genotypes was 2.29 (95% CI 1.17-4.49) in the dominant model, CC genotype 2.86 (95% CI 1.41-5.81) in the additive model, and C allele 1.57 (95% CI 1.17-2.1). The findings were replicated in an independent cohort of 372 obese and 390 normal weight Chinese children, where the odds ratio of obese subjects with CC and CG genotypes was 1.69 (95% CI 1.12-2.55). Within the Da Qing cohort, subjects with the GG genotype had significantly lower BMI and percentage ideal weight for height (WFH) at 5 and 8years of age. Subjects with lower birth weights also had more pronounced difference in WFH and BMI at 5 and 10years of age between GG subjects versus CC/CG subjects. We postulate that GG genotype is protective against excessive weight gain, and factors which predispose to excessive weight gain such as higher birth weights may ameliorate the effect.

Stem cell therapy for diabetes

Stem cell therapy holds immense promise for the treatment of patients with diabetes mellitus. Research on the ability of human embryonic stem cells to differentiate into islet cells has defined the developmental stages and transcription factors involved in this process. However, the clinical applications of human embryonic stem cells are limited by ethical concerns, as well as the potential for teratoma formation. As a consequence, alternative forms of stem cell therapies, such as induced pluripotent stem cells, umbilical cord stem cells and bone marrow-derived mesenchymal stem cells, have become an area of intense study. Recent advances in stem cell therapy may turn this into a realistic treatment for diabetes in the near future.

Glutathione deficiency in type 2 diabetes impairs cytokine responses and control of intracellular bacteria

Individuals with type 2 diabetes are at increased risk of acquiring melioidosis, a disease caused by Burkholderia pseudomallei infection. Although up to half of melioidosis patients have underlying diabetes, the mechanisms involved in this increased susceptibility are unknown. We found that B. pseudomallei-infected PBMCs from diabetic patients were impaired in IL-12p70 production, which resulted in decreased IFN-γ induction and poor bacterial killing. The defect was specific to the IL-12-IFN-γ axis. Defective IL-12 production was also observed during Mycobacterium tuberculosis infection, in which diabetes is likewise known to be a strong risk factor. In contrast, IL-12 production in diabetic cells was not affected upon Salmonella enterica infection or in response to TLR2, -3, -4, and -5 ligands. Poor IL-12 production correlated with a deficiency in intracellular reduced glutathione (GSH) concentrations in diabetic patients. Addition of GSH or N-acetylcysteine to PBMCs selectively restored IL-12 and IFN-γ production and improved bacterial killing. Furthermore, the depletion of GSH in mice led to increased susceptibility to melioidosis, reduced production of IL-12p70, and poorer disease outcome. Our data thus establish a link between GSH deficiency in diabetes and increased susceptibility to melioidosis that may open up new therapeutic avenues to protect diabetic patients against some intracellular bacterial pathogens.

Characterization of human umbilical cord lining-derived epithelial cells and transplantation potential

In this study we describe the derivation and immunological characterization of a primary epithelial cell type from the human umbilical cord membrane. These cord lining epithelial cells (CLECs) expressed and/or secreted isoforms of the nonclassical human leukocyte antigen class I (HLA-1b) glycoproteins, HLA-G and E. Conditioned media from CLECs inhibited mitogen-stimulated T-lymphocyte responses, and in a mixed leukocyte reaction (MLR) assay, cocultured CLECs inhibited allogeneic responses with a concomitant reduction in proinflammatory cytokines. Using a transwell coculture system, it was demonstrated that these immunoregulatory effects were mediated by soluble factors secreted by CLECs, in a dose-dependent manner. Functional studies using HLA-G blocking antibody showed that the effects of CLEC-secreted products could be inhibited, thus demonstrating a significant and important role for soluble HLA-G. In vivo, we show that transplanted CLECs could be maintained for extended periods in immunocompetent mice where xenorejection rapidly destroyed primary keratinocytes, a control human epithelial cell type. Additionally, CLECs delayed the rejection of keratinocytes and extended their survival when cotransplanted, indicating an ability to protect adjacent human cell types that would otherwise be rejected if transplanted alone. We also show that CLECs transduced with a modified human proinsulin gene were transplanted intraperitoneally into streptozotocin (STZ)-induced diabetic mice, resulting in significantly lower levels of serum glucose compared to control mice. This study has characterized the immunological properties of CLECs and tested a potential therapeutic application in the treatment of a type 1 diabetes mouse model.

Stem cell and gene therapies for diabetes mellitus

In this Perspectives article, we comment on the progress in experimental stem cell and gene therapies that might one day become a clinical reality for the treatment of patients with diabetes mellitus. Research on the ability of human embryonic stem cells to differentiate into islet cells has defined the developmental stages and transcription factors involved in this process. However, the clinical applications of human embryonic stem cells are limited by ethical concerns, as well as the potential for teratoma formation. As a consequence, alternative forms of stem cell therapies, such as induced pluripotent stem cells and bone marrow-derived mesenchymal stem cells, have become an area of intense study. Finally, gene therapy shows some promise for the generation of insulin-producing cells. Here, we discuss two of the most frequently used approaches: in vitro gene delivery into cells which are then transplanted into the recipient and direct delivery of genes in vivo.

Dual blockade of the renin-angiotensin-aldosterone system is safe and effective in reducing albuminuria in Asian type 2 diabetic patients with nephropathy

INTRODUCTION

Blockade of the renin-angiotensin-aldosterone system (RAAS) by either the angiotensin converting enzyme inhibitor (ACE-I) or the angiotensin II receptor blocker (ARB) has been shown to reduce albuminuria and delay the progression of diabetic nephropathy. This study evaluated the effect of dual blockade of the RAAS by adding an ACEI or an ARB to the administration of either drug alone on albuminuria in Asian type 2 diabetic patients with nephropathy.

METHODS

34 patients were randomly assigned to receive either enalapril 20 mg or losartan 100 mg once daily for eight weeks. Following this, all patients received a combination of enalapril 10 mg and losartan 50 mg daily for eight weeks, followed by enalapril 20 mg and losartan 100 mg daily for another eight weeks. The blood pressure and 24-hour urinary albumin excretion (UAE) were monitored.

RESULTS

Following monotherapy with enalapril, there was a mean and standard error (SE) reduction in the UAE and mean arterial pressure (MAP) of 9.8 (SE 6.8) percent (p-value is 0.061) and 5.3 (SE 2.2) mmHg (p-value is 0.026), respectively; the reduction in UAE and MAP following monotherapy with losartan was by 10.9 (SE 14.1) percent (p-value is 0.053) and 4.5 (SE 1.9) mmHg (p-value is 0.034), respectively. Combination therapy with enalapril and losartan further reduced the UAE (11.2 [SE 8.7] percent, p-value is 0.009] despite there being no significant change in the MAP (-1.2 [SE 1.47] mmHg, p-value is 0.42). The adverse effects included dry cough (seven [19.4 percent] patients, resulting in the withdrawal of medication in two patients), and transient hyperkalaemia (two [six percent] patients).

CONCLUSION

Dual blockade of the RAAS is safe and effective in reducing albuminuria in Asian type 2 diabetic patients with nephropathy.

Type 2 diabetic patients with resistant hypertension should be screened for primary aldosteronism

BP control in diabetic patients is often poor. The contribution of secondary hypertension due to undiagnosed PA in hypertensive type 2 diabetic patients is not well studied. We prospectively screened 100 consecutive Asian type 2 diabetic patients with difficult-to-control or resistant hypertension for PA. PAC (pmol/L) to PRA (ng/mL/h) ratio was measured; those with PAC-to-PRA ratio >550 (corresponding PAC >415) underwent intravenous 0.9% SLT. Patients with PAC >/=140 following SLT had CT adrenals and bilateral AVS. Thirteen patients (13%) were confirmed to have PA, and all had resistant hypertension. Eight had a surgically correctable form of PA. Patients with PA had higher mean (SD) systolic [159.0 (10.6) vs. 146.0 (10.7) mmHg, p=0.001] and diastolic BP [94.6 (6.0) vs. 87.6 (5.9) mmHg, p=0.001], lower serum potassium [3.5 (0.6) vs. 4.3 (0.5) mmol/L, p=0.001], and higher PAC [679.3 (291.0) vs. 239.5 (169.4) pmol/L, p=0.001]. Identification and institution of definitive treatment for PA resulted in better BP control and in a reduction in the use of antihypertensive medications. Our findings demonstrate a high prevalence of PA in type 2 diabetic patients with resistant hypertension. Systematic screening for PA in this select group is recommended, as targeted treatment improves BP control.

Skeletal myoblast transplantation for attenuation of hyperglycaemia, hyperinsulinaemia and glucose intolerance in a mouse model of type 2 diabetes mellitus

AIMS/HYPOTHESIS

We aimed to demonstrate the feasibility and efficacy of intra-muscular transplantation of human skeletal myoblasts (hSkMs) for attenuation of hyperglycaemia and improvement of insulin sensitivity using a mouse model of type 2 diabetes mellitus.

METHODS

KK Cg-Ay/J mice, aged 12 to 14 weeks, underwent an initial intraperitoneal glucose tolerance test (GTT) and were divided into the following groups: KK control group, basal medium (M199) only; KK myoblast group, with hSkM transplantation; KK fibroblast group, with human fibroblast transplantation. Non-diabetic C57BL mice were used as an additional normal control and also had hSkM transplantation. Cells were transplanted intra-muscularly into the skeletal muscles of the mice. All animals were treated with ciclosporin for 6 weeks only. HbA(1c) and fasting GTT, as well as serum adiponectin, cholesterol, insulin and triacylglycerol were studied.

RESULTS

Immunohistochemistry studies showed extensive survival of the transplanted hSkMs in the skeletal muscles at 12 weeks, with nuclei of the hSkMs integrated into the host muscle fibres. Repeat GTT showed a significant decrease in glucose concentrations in the KK myoblast group compared with the KK control and KK fibroblast groups. The KK myoblast group also had reduced mean HbA(1c), cholesterol, insulin and triacylglycerol, and increased adiponectin compared with the KK control and KK fibroblast groups. C57BL mice showed no change in glucose homeostasis after hSkM transplant.

CONCLUSIONS/INTERPRETATION

Human skeletal myoblast transplantation attenuated hyperglycaemia and hyperinsulinaemia and improved glucose tolerance in the KK mouse. This novel approach of improving muscle insulin resistance may be a potential alternative treatment for type 2 diabetes mellitus.

[Distribution of polymorphism in endothelial nitric oxide synthase gene in Singapore Chinese and its association with diabetic nephropathy]

OBJECTIVE

To examine the distribution of intron 4 polymorphism in endothelial nitric oxide synthase (eNOS) gene in mainland Chinese and Singapore Chinese and its association with diabetic nephropathy (DN).

METHODS

Peripheral blood samples were collected from 237 diabetes patients with the diabetic duration longer than 10 years, 87 mainland Chinese who visited the Qilu Hospital, Shandong province, and diabetic duration and blood sugar control-matched 150 Singapore Chinese who visited the Singapore National University Hospital. DNA extraction, PCR, cloning, and sequencing were conducted.

RESULTS

The 27 bp repeat polymorphism in intron 4 was tri allelic (a, b, and c alleles) in the Singapore Chinese while biallelic (a and b alleles) in the mainland Chinese. A third allele-allele c, with six 27 bp repeats was found. Significant difference was identified in the a allele distribution between the mainland and the Singapore Chinese (P < 0.001), but the intron 4 polymorphism didn't show any association with DN.

CONCLUSION

The intron 4 polymorphism is tri allelic, and the a allele distribution is not significantly associated with DN.

Oral hypoglycaemic agents for diabetes in pregnancy - an appraisal of the current evidence for oral anti-diabetic drug use in pregnancy

INTRODUCTION

The use of oral hypoglycaemic drugs in pregnancy is not recommended because of reports of foetal anomalies and other adverse outcomes in animal studies and in some human cases. However, recent studies have suggested that some oral hypoglycaemic drugs may be used in pregnancy. This review will examine these studies critically.

METHODS

Literature review of articles obtained from a PubMed search of peer-reviewed journals on oral hypoglycaemic drug use in pregnancy.

RESULTS

In two prospective studies, one of which was a randomised controlled trial, glibenclamide was as effective and safe as insulin in gestational diabetes. In several studies, metformin did not increase foetal anomalies or malformations when used during pregnancy in women with polycystic ovary syndrome (PCOS). In one prospective study on infants born to mothers who used metformin in pregnancy, follow-up for 18 months showed no adverse effects. In several prospective and retrospective studies on women with PCOS, metformin was shown to prevent early pregnancy loss, decrease insulin resistance, reduce insulin and testosterone levels, and decrease the incidence of gestational diabetes when these women got pregnant while on metformin and continued to take it throughout their pregnancy. In a single small study, acarbose did not cause any adverse effects during pregnancy.

CONCLUSIONS

Recent evidence shows promising findings in the safety and efficacy of some oral hypoglycaemic agents in treating pregnant diabetics. However, larger clinical studies will be needed to ensure the safety and efficacy of these drugs in pregnancy.

Recurrent episodes of arthritis in a hyperthyroid patient

Antineutrophil cytoplasmic antibody (ANCA)- associated vasculitis is a potentially life-threatening adverse effect of antithyroid medications. We present a 22-year-old woman with Graves' disease who developed recurrent episodes of arthritis while on treatment with propylthiouracil. A diagnosis of propylthiouracil-induced ANCA-associated vasculitis was established only after exhaustive rheumatological investigations failed to establish a cause for her arthritis. Anti-myeloperoxidase antibody (anti-MPO) titres were grossly elevated at 172.7 RU/mL (0-20). Her arthritis resolved promptly following the withdrawal of propylthiouracil and the anti-MPO titres declined over 16 months to 66.8 RU/mL. While she did not develop the life-threatening renal or respiratory tract complications, there was a delay in establishing the correct diagnosis with its attendant morbidity. This case highlights the need for greater awareness of this relatively rare adverse effect of antithyroid medications so as to allow its early detection, leading to the prompt cessation of the offending medication.

Ethanol feeding impairs insulin-stimulated glucose uptake in isolated rat skeletal muscle: role of Gs alpha and cAMP

BACKGROUND

The mechanism by which chronic alcohol consumption impairs insulin sensitivity is unclear. We investigated the role of the Gs alpha-mediated pathway in decreasing insulin sensitivity in skeletal muscle after ethanol consumption.

METHODS

Sixty male Wistar rats, divided into four groups, received either distilled water (controls; group I) or ethanol, which was administered by a gastric tube as a single daily dose of 5 g/kg (group II), 2.5 g/kg (group III), or 0.5 g/kg (group IV). After 20 weeks, fasting plasma glucose and serum insulin levels were measured. The hyperinsulinemic-euglycemic clamp study was performed under anesthesia to estimate whole-body insulin sensitivity. Insulin-stimulated glucose uptake was measured in vitro in dissected gastrocnemius muscle. Expression of glut4, Gs alpha, and Gi alpha was quantified using real-time PCR analysis and western blotting. cAMP levels were measured by ELISA.

RESULTS

Compared with controls, the following observations were made: (1) the hyperinsulinemic-euglycemic clamp study revealed impaired insulin action at the whole-body level after ethanol treatment; (2) chronic ethanol feeding at 5 g/kg and 2.5 g/kg significantly decreased both basal and insulin-stimulated glucose uptakes in isolated skeletal muscle (p<0.05), which was accompanied by decreased expression of glut4 (p<0.05); (3) Gs alpha (mRNA and protein) expression in skeletal muscle was significantly increased in all three ethanol groups (p<0.05), and cAMP levels were also increased by ethanol treatment (p<0.05); and (4) there was no significant change in Gi alpha expression in all three ethanol groups.

CONCLUSIONS

Chronic ethanol exposure decreased insulin-induced glucose uptake in rat skeletal muscle, which was associated with increased expression of Gs alpha. Because Gs alpha is a negative regulator of insulin sensitivity, the alteration in Gs alpha expression may contribute to the ethanol-induced impairment of insulin signal transduction.

Parathyroid carcinoma: a case series

INTRODUCTION

We present 3 patients with parathyroid carcinoma and describe their presentations, clinical profiles, and management.

MATERIALS AND METHODS

A case series review of medical records.

RESULTS

Two women and 1 man (age range, 32 to 57 years) had parathyroid cancer and primary hyperparathyroidism (PHPT). One patient presented with osteitis fibrosa, 1 with renal stone and a neck mass, and 1 with recurrence of PHPT after excision of supposedly benign parathyroid adenoma 4 years ago. All had severe hypercalcaemia and elevated parathyroid hormone levels that ranged from 4 to 43 times above the normal range. Exploration of the neck clearly identified 1 parathyroid tumour with local invasion; 2 other specimens showed capsular and vascular invasion on frozen section and final histology. All 3 patients underwent parathyroidectomy and ipsilateral hemithyroidectomy. Parathyroid size ranged from 1.3 to 4 cm and no lymph node metastasis was identified. No patient had tumour recurrence after a follow-up period of 1 year.

CONCLUSION

Parathyroid carcinoma is a rare endocrine malignancy. Suspicious features include marked hypercalcaemia, neck mass, and local recurrence. Parathyroidectomy with ipsilateral hemithyroidectomy and nodal clearance gives the best chance of reducing local tumour recurrence.

Xenotransplantation of neonatal porcine islets and Sertoli cells into nonimmunosuppressed streptozotocin-induced diabetic rats

The testis has been shown to be a privileged site for transplantation of allogenic islets in rodents, and the testicular cell aggregates are thought to confer this immunologic privilege. Recently, a group in Mexico reported transplantation of cocultured neonatal porcine islets and Sertoli cells resulting in insulin independence in nonimmunosuppressed type 1 diabetes patients. We have transplanted similar islets alone (naked islets) or cocultured islets with Sertoli cells (islet/Sertoli cells) into an omental site and other locations of nonimmunosuppressed, streptozotocin-induced diabetic male Sprague Dawley (SD) rats. Histologic examination showed viable neonatal porcine islets survived in xenografted rodents for at least 2 days, and some glucagon and inhibin stained cells appear to have survived for 4 days posttransplantation. However, histological examination did not demonstrate any difference in xenograft survival in the islets/Sertoli cells mixture compared to naked islets when transplanted into these nonimmunosuppressed diabetic rats.

Transplantation of neonatal porcine islets and sertoli cells into nonimmunosuppressed nonhuman primates

A Mexican group reported transplantation of cocultured neonatal porcine islets and Sertoli cells resulting in insulin independence in nonimmunosuppressed type 1 diabetes patients. We have transplanted similar islets alone (naked islets) or cocultured islets with sertoli cells (islet/sertoli cells) into an omental site and other locations of seven nondiabetic, nonimmunosuppressed, nonhuman primates. Porcine endogenous retrovirus was not detected in recipient blood 8 weeks after porcine islet grafts, and porcine C-peptide was detected at a very low level in all animals. Histology examination failed to demonstrate obviously recognizable islets, but in the animals transplanted with islet/Sertoli cells at the omentum site, there were some surviving glucagons, pan-cytokeratin, and inhibin stained cells at 8 weeks.

Does growth hormone prevent aging in the healthy elderly with low serum insulin-like growth factor-I ?

Aging is associated with a gradual decline in the function of a number of endocrine glands. While there are phenotypic similarities seen in the changes of aging with some endocrine hormone deficiency states, the relationship between the decline in growth hormone (GH) secretion, and the decrease in serum insulin-like growth factor-I (IGF-I), with these body composition changes is far from clear. The decline in serum IGF-I, unlike that of thyroxine and estradiol, is not accompanied by an increase in pituitary GH secretion. The recent enthusiastic recommendation for GH 'replacement' in the aging population with low serum IGF-I remains highly controversial. The evidence is still unclear on any significant beneficial effect of such replacement in healthy fit elderly men and women. There is some early evidence of beneficial effects of such replacement in the frail elderly. There are no studies that have investigated the effect of GH on longevity in humans, but results from animal studies on caloric restriction and longevity do not suggest that GH administration will increase life span. There is still insufficient evidence that treatment with exogenous GH in the healthy elderly that attains serum IGF-I levels similar to that of young adults is beneficial or safe.

Anaplastic thyroid carcinoma with destructive thyrotoxicosis in a patient with preexisting multinodular goiter

Presentation of anaplastic thyroid carcinoma with thyrotoxicosis is extremely rare and its occurrence in a patient with Wegener's granulomatosis has not been reported previously. We describe an elderly lady with Wegener's granulomatosis who developed a rapidly growing anaplastic thyroid carcinoma in a preexisting multinodular goiter and discuss the mechanism of thyrotoxicosis in this patient.

Autocrine human growth hormone (hGH) regulation of human mammary carcinoma cell gene expression. Identification of CHOP as a mediator of hGH-stimulated human mammary carcinoma cell survival

By use of cDNA array technology we have screened 588 genes to determine the effect of autocrine production of human growth hormone (hGH) on gene expression in human mammary carcinoma cells. We have used a previously described cellular model to study autocrine hGH function in which the hGH gene or a translation-deficient hGH gene was stably transfected into MCF-7 cells. Fifty two of the screened genes were regulated, either positively () or negatively (), by autocrine production of hGH. We have now characterized the role of one of the up-regulated genes, chop (gadd153), in the effect of autocrine production of hGH on mammary carcinoma cell number. The effect of autocrine production of hGH on the level of CHOP mRNA was exerted at the transcriptional level as autocrine hGH increased chloramphenicol acetyltransferase production from a reporter plasmid containing a 1-kilobase pair fragment of the chop promoter. The autocrine hGH-stimulated increase in CHOP mRNA also resulted in an increase in CHOP protein. As a consequence, autocrine hGH stimulation of CHOP-mediated transcriptional activation was increased. Stable transfection of human CHOP cDNA into mammary carcinoma cells demonstrated that CHOP functioned not as a mediator of hGH-stimulated mitogenesis but rather enhanced the protection from apoptosis afforded by hGH in a p38 MAPK-dependent manner. Thus transcriptional up-regulation of chop is one mechanism by which hGH regulates mammary carcinoma cell number.