Increased levels of platelet-derived growth factor in vitreous fluid of patients with proliferative diabetic retinopathy.

UNLABELLED: It is generally accepted that growth factors play an important role in the pathogenesis of proliferative diabetic retinopathy. Since platelet-derived growth factor AB (PDGF AB) is known to be involved in many angiogenetic and proliferative processes, it was the aim of our study to elucidate the role of PDGF AB in the angiogenetic process in proliferative diabetic retinopathy. We measured PDGF AB concentrations in the vitreous of 23 patients with proliferative diabetic retinopathy, 4 of them with additional rubeosis iridis as an indicator of very high vasoproliferative activity. Control measurements were done in 19 patients without diabetic or ischemic eye diseases and also in 4 non-diabetic patients with ischemic proliferative retinopathy with rubeosis iridis. To exclude PDGF remnants in the vitreous due to vitreous bleeding we additionally measured platelet factor 4 concentrations as a stable marker of activated thrombocytes in the vitreous. RESULTS: Significantly elevated concentrations of PDGF AB were found in the vitreous of patients with proliferative diabetic retinopathy, with higher levels in individuals with additional rubeosis iridis compared to controls. However, concentrations of PDGF AB were also elevated in ischemic non-diabetic retinopathy, supporting the concept that ischemia might be a strong stimulator of growth factor production in the retina. Platelet factor 4 was not detectable in any of the vitreous samples included in the study. In summary, our results indicate that the growth factor PDGF plays an important role in the pathogenesis of proliferative diabetic retinopathy, probably in synergistic action with other growth factors like IGF I, IGF II, VEGF and TNF alpha.

Circulating tumor necrosis factor alpha is elevated in male but not in female patients with type II diabetes mellitus.

The cytokine tumor necrosis factor alpha (TNF alpha) was proposed to mediate obesity related insulin resistance upon production in fat cells and to participate in tissue remodelling leading to vascular complications upon being released by macrophages. To assess its putative role in diabetes we determined plasma levels of TNF alpha in 105 adult humans. Male nondiabetic subjects had significantly lower TNF alpha levels than female controls (4.4 +/- 0.3, n = 17 vs. 6.6 +/- 1.0 pg/ml, n = 13; p = 0.049). Men with NIDDM had elevated TNF alpha (6.7 +/- 0.6 pg/ml, n = 34) compared to nondiabetic subjects (4.4 +/- 0.3 pg/ml, n = 17; p = 0.012). Such a difference was not apparent in women. Levels of TNF alpha were correlated with serum triglyceride levels in male controls (r2 = 0.64; p = 0.007) but not in NIDDM. Neither body mass index nor glycosylated hemoglobin correlated with TNF alpha in any of the groups. The presence of retinopathy (p = 0.046) but not of neuropathy or nephropathy or macroangiopathy was associated with significantly elevated plasma TNF alpha. We conclude that plasma levels of TNF alpha are sex-dependent and that increased TNF alpha occurs in male but not female NIDDM and may participate in the development of diabetic complications.

Long-term adherence to intensified conventional insulin therapy.

All diabetic patients of the outpatient clinic of the University of Frankfurt/Main, who started intensified conventional insulin therapy (ICT) between 1980 and 1991, and who could be followed for at least one year (n = 141) were evaluated retrospectively. Fourteen patients changed from ICT to continuous subcutaneous insulin infusion (CSII). No patient changed back permanently to conventional insulin therapy. Mean glycosylated hemoglobin-levels (HbA1) decreased significantly in the first year from 9.3% to 8.5% and remained at a near normal level in the following years. HbA1-levels were found not to be associated with age, age at diagnosis, weight gain, frequency of visits to the outpatient clinic, number of consultations with the dietician as well as the frequency of attendance at special seminars for ICT. These results demonstrate that ICT lowered blood glucose levels permanently, that patients were highly compliant, and that ICT was practicable and safe for long-term treatment under routine conditions without initial hospitalization and with an acceptable expenditure of time for patients and medical staff.

[Regression of hard exudates in diabetic background retinopathy in therapy with etofibrate antilipemic agent]. / Rückbildung harter Exsudate bei diabetischer Hintergrundretinopathie unter Therapie mit dem Lipidsenker Etofibrat.

BACKGROUND: The aim of this pilot study was to investigate the influence of a lipid lowering therapy with etofibrate on the progression of diabetic background retinopathy in patients with diabetes mellitus and combined hyperlipoproteinemia. In addition to the well known correlation between the duration of diabetes and the quality of blood glucose control, a correlation between diabetic microangiopathy and elevated triglyceride levels is discussed for many years. The most important pathogenic mechanisms in this respect seem to be an elevation of blood viscosity and alterations in the fibrinolytic system. Fibrinogen and triglycerides are the main determinants of plasma viscosity. As lipid lowering drugs containing fibrates and nicotinic acid are able to lower triglycerides and fibrinogen effectively, a favourable therapeutic effect on the progression of diabetic retinopathy may be expected. PATIENTS AND METHOD: 11 type II diabetics with combined hyperlipoproteinemia (Fredrickson type IIb) and mild to moderate background retinopathy detected by fundus photography were treated with etofibrate (2 x 500 mg/day) for a period of 6 months. RESULTS: In 7 of 10 patients hard exudates, which had been present at the beginning of treatment, showed clear regression at the end of the treatment period. Among the laboratory test parameters a significant 30% reduction of triglycerides (p < 0.010) was observed. There was also a clear 25% increase in HDL cholesterol and a 12% fibrinogen reduction. Considerable changes of the quality of blood glucose control were not evident during the treatment period. CONCLUSION: Treatment with the lipid lowering drug etofibrate seems to produce favourable therapeutic effects on hard exudates in diabetic background retinopathy in patients with diabetes mellitus and combined hyperlipoproteinemia. The mechanisms of this effect are not yet clearly understood, in addition to positive effects on the microcirculation of the retina by lowering blood viscosity there is a direct lipolytic effect in the area of hard exudates to be discussed, too. It is important to point out that we did not see any positive effect of etofibrate therapy concerning other morphological changes of diabetic background retinopathy, i.e. microaneurysms or hemorrhages in our pilot study.

Long-term compliance of intensified insulin therapy.

Results of the DCCT trial (N. Engl. J. Med. 329, 977-986) demonstrate that therapy in insulin-dependent diabetes mellitus (IDDM) should aim at near-normoglycemia. For reaching this standard, intensified insulin therapy--either intensified conventional therapy (ICT) or continuous subcutaneous insulin infusion (CSII)--is mandatory. These regimes demand much long-term motivation and discipline from the diabetics. With > 95%, long-term compliance of ICT is good, according to the few published data available and our own experience. For CSII, on the other hand, cumulated studies reveal discontinuation rates ranging from 0% to 36%, averaging 20.4% and being significantly correlated with metabolic control before start of CSII in terms of glycosylated hemoglobin levels (r = 0.66; P < 0.05). The major reasons for discontinuation of CSII were skin problems (22.1%), inconvenience of the pump (21.4%) and lack of metabolic improvement (9.6%). A conclusion drawn from these meta-analytical data is that a stepwise approach to CSII is recommended for increasing compliance. A period of ICT long enough to gain experience with blood glucose self-control and self-adjustment of meal-related insulin should precede CSII. Furthermore, a general increase of CSII among IDDM patients is necessary to come closer to the standard of near-normoglycemia for these diabetics. Therefore, diabetes treatment and education resources must be improved, especially concerning psychosocial problem solving and cooperation between diabetologists and general practitioners.

HLA-DR3 and HLA-DR5 confer risk for autoantibody positivity against the thyroperoxidase (mic-TPO) antigen in healthy blood donors.

The prevalence of circulating autoantibodies against thyroperoxidase (mic-TPO) was determined in 3,000 healthy blood donors (age range: 23 to 60 years) from the Hamburg area. Of the blood donors, 153 (5.1%) were found to have high titer of mic-TPO (> 350 IU/ml). Only two autoantibody positive subjects (0.06%) were chemically hyper- and hypothyroid, respectively. Analysis of HLA-DR specificities revealed that HLA-DR specificities DR3 and DR5 were significantly increased when compared to controls (n = 1,863). Comparison of the autoantibody-positive probands with a group of disease controls, i.e., Graves' patients and patients with lymphocytic thyroiditis, revealed a higher prevalence of HLA-DR3-positive HLA haplotypes in the disease controls when compared to autoantibody positives. Individuals with a mic-TPO level greater than 2,000 IU/ml were almost exclusively found to have one HLA-DR3 or HLA-DR5 positive HLA haplotype. We conclude that a high prevalence of high-titer mic-TPO can be found in healthy blood donors. Circulating signs of thyroid autoimmunity were associated with HLA specificities also found to be associated with autoimmune thyroid diseases.

HLA-DRB3 gene alleles in Caucasian patients with Graves' disease.

Graves' disease (GD) is a human leukocyte antigen (HLA) linked organ-specific autoimmune disease. In German GD patients the disease is associated with HLA specificities of the HLA-DRw52 family (HLA-DR3, -DR5, and DR6; HLA-DRB3 positive HLA haplotypes). Recently, a strong association with a HLA-DRB3 restriction fragment length polymorphism gene has been described. To study HLA-DRB3 alleles and their association with the disease, a large cohort of controls (n = 3724) and GD patients (n = 304) was analyzed. HLA-DR allelic combinations revealed an increase in HLA-DR3/DR5 heterozygous patients (relative risk 2.9; P < 0.001). HLA-DRB3 alleles, as defined by DNA typing in HLA-DR matched groups revealed a significant increase in DRB3*0101 homozygosity (relative risk 17.5; P < 0.001) in HLA-DR3 homozygous patients. In GD patients with ophthalmopathy (grade II or higher, according to Werner) DRB3*0101/*0202 heterozygosity revealed an increased relative risk of 5.5 (P < 0.001). Non-HLA-DR3 homozygous, DRB3*0101/*0202 heterozygous patients were at the highest risk for endocrine ophthalmopathy (relative risk 10; P < 0.001). Our data, based on DNA typing methods of HLA-D genes, provide evidence that the susceptibility is strongly associated with HLA-DRB3 genes.

HLA-DR3 and variations of the T cell receptor beta gene in Graves' disease.

The association of Graves' disease with two allelic forms of the T cell receptor beta-chain gene (Bgl II restriction fragments 9.2/10.0 kb) was analysed in Caucasians suffering from Graves' disease (N = 54), randomly selected controls (N = 68), and HLA-DR3 homozygous typing control subjects (N = 12). While gene frequencies did not vary in the latter two groups, a significant reduction of 9.2 kb homozygosity was observed in patients with Graves' disease (11 vs 32%, chi 2 = 7.68, p less than 0.01, RR = 0.26). The excess of the 9.2/10.0 kb heterozygosity in patients, which is restricted to the DR3-positive individuals, did not reach significance. The increase in heterozygosity of genomic T cell receptor beta-chain polymorphisms may be attributed to the role the beta-chain plays in autoantigen recognition in Graves' disease.

Immunogenetic markers in patients with Graves' disease.

110 carefully characterized Caucasoid patients with Graves' disease were tested for HLA class I and class II antigens. Compared with Caucasian controls (n = 193), the frequencies of HLA B8, Cw7 and DR3 were significantly increased (pc less than 0.05). In the subgroups with and without exophthalmos, HLA A3 exhibited a negative but insignificant association with the eye involvement, while A19 and Cw2 showed positive, however even weaker correlations with eye disease. HLA DR5 was associated with relapsing thyrotoxicosis, whereas HLA DR7 and B12 were negatively correlated with relapse. These results confirm the positive correlation of HLA B8 and DR3 with Graves' disease and reveal a not yet observed association with Cw7. Reported correlations of antigen frequencies with eye disease and relapsing thyrotoxicosis could not be confirmed. Other previously unknown, however subtle differences in disease subgroups were observed.

[Long-term treatment of acromegaly with the somatostatin analog octreotide (Sandostatin). On the predictive significance of acute tests]. / Langzeitbehandlung der Akromegalie mit dem Somatostatinanalogon Octreotid (Sandostatin). Zur prädiktiven Bedeutung von Akuttests.

Twelve acromegalic patients were treated (mean +/- SD) 26 +/- 15 months with daily doses of 440 +/- 330 micrograms of the somatostatin analogue octreotide acetate (SMS 201-995, Sandostatin). The levels of somatomedin-C (Sm-C) decreased by 63% from 8.1 +/- 7.7 U/ml to 3.0 +/- 1.3 U/ml. Before starting therapy a long oral glucose tolerance test (oGTT) and a TRH test were performed both without and after s.c. injection of 100 micrograms octreotide. Under long-term treatment with octreotide four of twelve patients reached normal Sm-C-values. The GH levels of all of these patients were continuously suppressed to less than 2 ng/dl in an oGTT after a test dose of 100 micrograms octreotide s.c. till the end of the test (5 1/2 hours after octreotide injection). The other eight patients had a relief of acromegalic symptoms and five had a decrease of their Sm-C-levels, but none of them reached normal Sm-C-values. None of these patients had a continuous suppression of GH after a test dose of octreotide in an oGTT. Hyperprolactinemia (n = 4) was observed only in those patients with an insufficient response to octreotide. The GH-response to TRH showed neither without nor after injection of octreotide a correlation with the results of long-term treatment. Thus it is concluded that GH-suppression in a long oGTT after administration of a test dose of 100 micrograms octreotide acetate s.c. allows to identify those acromegalic patients who will benefit from long-term treatment with the somatostatin analogue octreotide acetate.

The HLA-DR4-associated DQw8 allele is confined to HLA-DR3/DR4 heterozygous type I (insulin-dependent) diabetics.

The HLA-DR4 specificity revealed a relative risk of 8.5 (chi 2 = 99.6; p less than 0.0001) when 193 type I diabetics were compared to 305 controls. Prevalence of the HLA-DR4-associated DQ types, i.e. DQw7 and DQw8, were determined, using a restriction fragment length polymorphism (RFLP) typing that combines the probe/enzyme combinations DQB/Taq I and DQB/Bam HI. The HLA-DQw8 specificity was confined to HLA-DR3/DR4 heterozygous patients when compared to controls (chi 2 = 4.9; p less than 0.025) or to all other DR4-heterozygous patients (chi 2 = 6.7; p less than 0.01). No association with HLA-DQw8 was seen in HLA-DR1/DR4 or HLA-DR"X"/DR4 (X not equal to 1,3,4) heterozygous patients. Due to the excess of HLA-DR3/DR4 patients the DQw8 allele is a risk factor in type I diabetics, but in HLA-DR1/DR4 and DRX/DR4 heterozygotes one might suggest that DQB1 and DRB combinations confer HLA-associated susceptibility.

[Compliance problems in therapy with levothyroxine]. / Compliance-Probleme bei der Therapie mit Levothyroxin.

In order to evaluate problems with long-term levothyroxine therapy, the course of treatment in 185 patients of an endocrinological outpatient ward (88 with euthyroid goiter, 41 with overt or latent hypothyroidism, ten with Hashimoto's thyroiditis, 46 after resection of goiter) was analyzed retrospectively. Duration of therapy ranged from one to 28 years. Suppressive therapy of euthyroid goiter was stopped by the treating physician in eleven patients (11%), in five permanently. To the contrary, 30 patients (34%) stopped medication by themselves 31 times, 29 times, however, levothyroxine was restarted again. Observations in the group with latent hypothyroidism were similar. After operation levothyroxine therapy was stopped by the physician eight times, six times only for a limited time period. Eight patients (17%) decided to stop therapy without knowledge of the treating physician, but in all it was restarted later. The presented results show that the success of levothyroxine therapy of euthyroid goiter as well as of prophylaxis of goiter relapse after operation is threatened by dyscompliance of the patients. In goiter suppression therapy compliance is further challenged by a lack of consequence in therapy planning and guidance.

Thyroid hormone binding inhibition in critically ill patients--who is the inhibitor?

In 31 severely ill patients of our intensive care unit an increased thyroid hormone binding inhibition detected by quantitative measurement of the effect of ether extracts of patients' sera on thyroxine tracer binding to TBG was found. As free fatty acids in serum were diminished in these patients, their postulated role as binding inhibitors in the "low T4 syndrome" of critically ill patients must be questioned. It cannot be excluded that THBI assays demonstrating this inhibition measure artefacts caused by heparine-induced in vitro lipolysis.

[The course of diffuse hyperthyroidism in Basedow disease]. / Verlauf der diffusen Hyperthyreose des Morbus Basedow.

An investigation of a large group of patients with Graves' disease demonstrates that this autoimmune disorder of the thyroid is a chronic process with an often protracted course and therefore requires virtually life-long management. Drug therapy (with thionamides) is associated with a high rate of relapse of 60-70%-reliable criteria for the cessation of the autoimmune process are not available. Surgical therapy may also fail to provide lasting control of hyperthyroidism.

Re-evaluation of eye muscle autoantibody determination in Graves' ophthalmopathy: failure to detect a specific antigen by use of enzyme-linked immunosorbent assay, indirect immunofluorescence, and immunoblotting techniques.

Sera from 41 patients with Graves' ophthalmopathy were investigated for presence of autoantibodies directed against eye muscle preparations using different methods: 1. ELISA with pork eye muscle membrane preparations; 2. Immunoblotting with glycoprotein preparations from human eye muscle; 3. Indirect immunofluorescence with human eye muscle sections. The ELISA was not suitable for detection of specific immunoglobulin binding with sera from patients suffering from endocrine ophthalmopathy. Immunoblotting exhibited only nonspecific binding to some muscle proteins; it could be prevented by pre-adsorption procedures and was not different from the pattern observed with skeletal muscle as antigen. The indirect immunofluorescence technique revealed no binding of Graves' sera to human muscle sections, whereas sera containing antibodies against skeletal muscle bound to eye muscle as well. Thus far, an antigenic structure of eye muscle specific for Graves' ophthalmopathy is not detectable with the methodology used here. The possibility that retroorbital connective tissue may be the main target of the autoimmune process must be considered.

[Injection aids for intermediate-term acting insulin. Experiences with the OptiPen]. / Injektionshilfen für mittellang wirkende Insuline. Erfahrungen mit dem OptiPen.

Twenty diabetics conventionally treated with Depot H and/or Basal H Insulin Hoechst received the OptiPen as an injection aid for the corresponding U100 insulin preparations. Seventeen patients had such a positive opinion of the pen, that they wanted to continue using it. After 15.6 +/- 5.3 weeks of "pen therapy", the mean insulin dose remained unchanged. In the 14 patients who had been treated with insulin long before the change over to the pen, the mean HbA1 level showed no change (8.8 +/- 1.2% before versus 8.7 +/- 1.5% under pen therapy). The use of an injection aid--in this case the OptiPen--facilitates insulin therapy for the usually older diabetics treated with intermediate acting or mixed insulin, too. Technical problems over the long term were not encountered and the quality of metabolic control remained unchanged.

Linkage of HLA-DR beta specific restriction fragment length polymorphisms with Graves' disease.

HLA-DR3 positive patients with Graves' disease (6 homozygotes, 7 heterozygotes, i.e. yielding 19 haplotypes) were studied by restriction fragment length polymorphism analysis using TaqI as restriction enzyme in order to look for polymorphisms in the HLA-DR3 allele of the human major histocompatibility complex. Polymorphic TaqI fragments of 11.6, 9.8 and 5.8 kb, each corresponding to HLA-DR beta sequences, were shown to differ in their prevalence in patients with Graves' disease and controls. The prevalence of DR3 polymorphisms in a total of 35 HLA-DR3-containing haplotypes was markedly different within patients with Graves' disease and Caucasian controls. Whereas a 11.6 kb fragment was rare in Graves' disease (2/19 haplotypes vs 8/16 in controls), the inverse ratio was found for a 9.8 kb fragment, with a prevalence of 17/19 and 8/16 haplotypes, respectively. A polymorphic fragment of 5.8 kb was exclusively seen in two DR3-containing haplotypes of patients with Graves' disease. Our data provide evidence that a DNA polymorphism of the HLA-DR beta genes, which is also reflected at the product level, is linked to Graves' disease.

[Free fatty acids in the serum in critical diseases: do they play a role in the protein binding of thyroid hormones?]. / Freie Fettsäuren im Serum bei krisenhaften Erkrankungen: Spielen sie eine Rolle bei der Proteinbindung von Schilddrüsenhormonen?

As a contribution to the question if the elevated concentrations of free fatty acids in sera of critically ill patients described in literature play a role in the decrease of thyroid hormone levels in these patients, serum levels of the important free fatty acids were measured in 31 patients of our intensive care unit in the course of their disease using gas chromatography. After admission to the ward, only palmitoleic acid was significantly increased compared with 174 control persons, arachidonic acid was not different from the controls, palmitic, stearic, linoleic and linolenic acid were significantly decreased. In the course of the disease, no relevant changes were observed. The 21 patients not surviving their disease showed significantly lowered levels of palmitic, stearic and linoleic acid before death compared with the surviving patients at the end of the observation period. The hypothetical role of single free fatty acids as inhibitors of the binding of thyroid hormones to their transport proteins must be questioned because of the results.