Micha J. Rapoport

Neonatal pig islets induce a lower T-cell response than adult pig islets in IDDM patients.

BACKGROUND Pancreatic pig islets may provide a substitute in the future for difficult to obtain human islets for transplantation in insulin-dependent diabetes millitus (IDDM) patients. However, the immune response to xenografts may significantly hamper this approach. Because neonatal tissue is believed to be less immunogenic, we examined whether the T-cell response to neonatal pig islets differs from the response to adult islets. METHODS The T-cell proliferative response to different concentrations of sonicated neonatal and adult pig islets, as well as to insulin and mitogens, was tested in 21 recent onset IDDM patients and 21 healthy controls. We determined the presence of various circulating islet autoantibodies and their association with the T-cell response in IDDM patients. RESULTS In the IDDM patients, sonicated adult pig islets (at 1 microg protein/ml) induced a significantly higher frequency (12 of 21 vs. 1 of 21, p<0.001) and magnitude (2.58+/-0.44 vs. 1.38+/-0.13, p<0.02) of positive T-cell responses than neonatal islets at the same concentration. Similar results were obtained with a 10-fold higher concentration of islet sonicate. There was no significant association between the individual T-cell responses and the presence of circulating autoantibodies in IDDM patients. CONCLUSION These results indicate that neonatal pig islets induce a lower T-cell reactivity than adult islets, suggesting that the neonatal tissue may be immunologically more suitable for future islet xenotransplantation.

Discordant effect of body mass index on bone mineral density and speed of sound

BackgroundIncreased BMI may affect the determination of bone mineral density (BMD) by dual X-ray absorptiometry (DXA) and speed of sound (SOS) measured across bones. Preliminary data suggest that axial SOS is less affected by soft tissue. The purpose of this study is to evaluate the effect of body mass index (BMI) on BMD and SOS measured along bones.MethodsWe compared axial BMD determined by DXA with SOS along the phalanx, radius and tibia in 22 overweight (BMI > 27 kg/m2), and 11 lean (BMI = 21 kg/m2) postmenopausal women. Serum bone specific alkaline phosphatase and urinary deoxypyridinoline excretion determined bone turnover.ResultsMean femoral neck – but not lumbar spine BMD was higher in the overweight – as compared with the lean group (0.70 ± 0.82, -0.99 ± 0.52, P < 0.00001). Femoral neck BMD in the overweight – but not in the lean group highly correlated with BMI (R = 0.68. P < 0.0001). Mean SOS at all measurement sites was similar in both groups and did not correlate with BMI. Bone turnover was similar in the two study groups.ConclusionsThe high BMI of postmenopausal women may result in spuriously high BMD. SOS measured along bones may be a more appropriate means for evaluating bones of overweight women.

Young patients with both type 1 diabetes mellitus and asthma have a unique IL-12 and IL-18 secretory pattern

Rachmiel M, Bloch O, Shaul AA, Ben‐Yehudah G, Bistritzer Z, Weintrob N, Ofan R, Rapoport MJ. Young patients with both type 1 diabetes mellitus and asthma have a unique IL‐12 and IL‐18 secretory pattern.

The cyclin kinase inhibitor p57kip2 regulates TGF-β-induced compensatory tubular hypertrophy: effect of the immunomodulator AS101

BACKGROUND Compensatory tubular cell hypertrophy following unilateral nephrectomy is a cell cycle-dependent process. Our previous study showed that treatment of unilaterally nephrectomized rats with the immunomodulator AS101 partially inhibits compensatory hypertrophy of the remaining kidneys through the inhibition of IL-10-induced TGF-beta secretion by mesangial cells. The present study is focused on understanding the intracellular mechanism(s) of this phenomenon. METHODS A total of 120 male Sprague-Dawley rats were unilaterally nephrectomized or sham-operated and treated with AS101 or PBS. Kidney weight and protein/DNA ratio were assessed for each experimental animal. The expression of TGF-beta, PCNA, CDK 2, pRb, ppRb, p21(Waf1), p27(kip1) and p57(kip2) proteins in renal tissues was determined by western blot analysis and immunohistochemistry, and the immunoprecipitation of cyclin E complexes was performed. RESULTS Compensatory renal growth is initiated by proliferation of resident renal cells that precedes hypertrophy. Changes in TGF-beta expression were positively correlated with the amounts of p57(kip2), but not with p21(Waf1) and p27(kip1) expression in the remaining kidneys. Moreover, there was a marked abundance of p57(kip2) but not p21(Waf1) and p27(kip1) binding to the cyclin E complex in PBS-treated unilaterally nephrectomized rats compared to sham-operated animals. Treatment of uninephrectomized rats with AS101 reduced kidney weight and protein/DNA ratio, inhibited TGF-beta and p57(kip2) expression in the remaining kidneys, and decreased the level of p57(kip2) binding to cyclin E complexes. CONCLUSION These results demonstrate that TGF-beta-induced compensatory tubular cell hypertrophy is regulated in vivo by p57(kip2) but not by the p21(Waf1) and p27(kip1) cyclin kinase inhibitor proteins.

Diagnosis of normocalcemic hyperparathyroidism by oral calcium loading test

We evaluated the oral calcium-loading test (OCLT) in diagnosing normocalcemic primary hyperparathyroidism. Calcium and PTH levels were measured before, 60, 120 and 180 min after oral 1 g of calcium gluconolactate administration in 102 consecutive females with high circulating PTH levels, and 25 controls. Patients were classified as follows: Group A, patients with a parathyroid adenoma identified by two imaging modalities. Sub-Group AO, hyper-parathyroid patients [no.=13, mean age 59 yr (SD=10)] evaluated prior to parathyroidectomy. Sub-Group AH, non-operated hypercalcemic patients [no.=29, age 63 yr (SD=11)]. Sub-Group AN, normocalcemic non-operated women [no.=14, age 59 yr (SD=8)]. Group B, normo-calcemic individuals [no.=46, age 58 yr (SD=11)] with negative parathyroid imaging. Group C, control patients [no.= 25, age 56 yr (SD= 12)]. The concentrations of calcium and PTH overlapped in the normocalcemic groups during the OCLT. Product P, defined as circulating PTH nadir (pg/ml) × peak calcium concentration (mg/dl), better discriminated Sub-Group AN from Group B, AUC=0.98 (95% CI 0.95, 1.00) than did Ratio R, defined as relative PTH decline/relative calcium increment, AUC= 0.86 (95%CI 0.73, 0.99). Assuming normal threshold of Product P and Ratio R at 260 and 17 respectively, the combined parameters diagnose normocalcemic hyperparathyroid patients with 100% sensitivity and 87% specificity.

A study of the clinical differences between women and men with hyperprolactinemia

A group of 64 women and 14 men with hyperprolactinemia were followed up in an endocrine service center for a mean of 43 months. The various parameters in each sex were compared. The mean age at first visit was 49 years in the men and 36 years in the women (p < 0.001). The peak prolactin index levels were 13.7 in the men and 5.5 in the women (p < 0.002). Macroprolactinomas were significantly more prevalent in the men (p < 0.002). The women complained significantly more about headache (p < 0.02), malaise (p < 0.02), restlessness (p < 0.03) and fatigue (p < 0.04). These symptoms had no correlation with the prolactin level. Thus, in the men the clinical manifestations of hyperprolactinemia came to attention at an older age and had a connection with a higher prevalence of macroprolactinoma. The possible mechanisms are discussed. Vague complaints, reported more often by the women, do not seem to correlate with the prolactin level.

GLP-1 Receptor Is Expressed in Human Stomach Mucosa Analysis of Its Cellular Association and Distribution within Gastric Glands

The stomach is a target organ of the incretin hormone glucagon-like peptide-1 (GLP-1). However, the cellular expression and glandular distribution of its receptor (GLP-1R) in human gastric mucosa are not known. We determined the expression of GLP-1R in different regions of human stomach mucosa and its specific cellular association and distribution within gastric glands. Tissue samples from stomach body and antrum were obtained from 20 patients during routine esophagogastroduodenoscopy. mRNA encoding GLP-1R protein expression was evaluated by RT-PCR. Determination of cell types bearing GLP-1R, their localization, and their frequency in gastric glands in different gastric regions were estimated by immunohistochemical morphological analysis. Levels of GLP-1R mRNA were similar in body and antrum. GLP-1R immunoreactivity was found throughout the gastric mucosa in various types of glandular cells. The highest frequency of GLP-1R immunoreactive cells was found in the neck area of the principal glands in cells morphologically identified as parietal cells. GLP-1R immunostaining was also found on enteroendocrine-like cells in the pyloric glands. This study provides the first description of GLP-1R expression in human gastric glands and its specific cellular association. Our data suggest that GLP-1 may act directly on the gastric mucosa to modulate its complex functions.

Defective activation of p21ras in peripheral blood mononuclear cells from patients with insulin dependent diabetes mellitus.

We previously reported that a decreased TCR mediated activity of the GTP-GDP binding p21ras protooncogene is associated with prediabetes in non-obese diabetic (NOD) mice. Furthermore, prevention of autoimmune diabetes is associated with reversal of the p21ras signaling defect in NOD T cells. Based on these animal studies we determined the activation of p21ras in PBMC from patients with Insulin Dependent Diabetes Mellitus (IDDM), Non-Insulin Dependent Diabetes Mellitus (NIDDM) and normal healthy controls. Stimulation by PHA induced a decrease of 3.7 +/- 1.4% and an increase of 2.44 +/- 2.3%, p < 0.02 and 2.6 +/- 1.6%,p < 0.003 in the basal unstimulated p21ras activity in the IDDM, NIDDM and normal control groups, respectively. Expression of p21ras and its regulatory elements, the GTPase activating protein p120ras-GAP and the guanine nucleotide releasing factor (GNRF) hSOS, was comparable in the three groups. The in vitro proliferative response to PHA was comparable in the IDDM and control groups: stimulation index (SI) of 8.6 +/- 2.5 and 9.4 +/- 3.5 respectively, p < 0.44. No correlations were found in the IDDM patients between the degree of p21ras activation and the mitogen induced in vitro proliferative response or the various clinical parameters including age, gender, disease duration, daily insulin requirements and metabolic control. Taken together these data indicate that PBMC from IDDM patients are characterized by a persistent impairment in the activation of their p21ras. They also suggest that p21ras stimulated activity is a sensitive and independent parameter of PBMC activation in these patients.

Interpreting the results of the Semmes-Weinstein monofilament test: accounting for false-positive answers in the international consensus on the diabetic foot protocol by a new model

The Semmes‐Weinstein monofilament is the most widely used test to diagnose the loss of protective sensation. The commonly used protocol of the International Consensus on the Diabetic Foot includes a ‘sham’ application that allows for false‐positive answers. We sought to study the heretofore unexamined significance of false‐positive answers.

Reduced GLP-1R Expression in Gastric Glands of Patients With Type 2 Diabetes Mellitus

BACKGROUND The incretin effect is reduced in type 2 diabetes mellitus (T2DM) patients. Whether the impaired function of the enteropancreatic axis in these patients is due to defective GLP-1 receptor (GLP-1R) expression in extrapancreatic target organs is not known. AIMS AND METHODS To compare the GLP-1R expression and distribution in gastric mucosa biopsies of patients with (n =22) and without (n =22) T2DM referred for routine esophagogastroduodenoscopies. GLP-1R mRNA levels were estimated by real-time PCR. The intensity of GLP-1R immunostaining, frequency, and types of glandular cells bearing GLP-1R and their glandular distribution in different stomach mucosa regions were evaluated by immunohistochemical morphological semiquantitative and quantitative analysis. RESULTS Mean mRNA GLP-1R levels were significantly reduced in patients with T2DM compared with nondiabetic patients (P < .02). Immunohistochemical analysis revealed that the reduced GLP-1R expression in T2DM patients was due to a decreased intensity of immunostaining (P < .01). The number of glandular GLP-1R-bearing cells in both body and antrum mucosa was decreased in T2DM patients. Most notably, the frequency of GLP-1R immunoreactive acid-secreting parietal cells was reduced in the neck area of the gastric principal glands of T2DM patients (P < .01). No correlation was found between the reduced GLP-1R expression and clinical parameters including body mass index, age, glycosylated hemoglobin, and disease duration. CONCLUSION This is the first evidence of reduced GLP-1R expression in gastric glands of T2DM patients. These data demonstrate that the defective function of the incretin axis in T2DM may also result from decreased GLP-1R expression in its extrapancreatic target organs.