Canadian Stroke Best Practice Recommendations: Acute Stroke Management, 7th Edition Practice Guidelines Update, 2022

The 2022 update of the Canadian Stroke Best Practice Recommendations (CSBPR) for Acute Stroke Management, 7th edition, is a comprehensive summary of current evidence-based recommendations, appropriate for use by an interdisciplinary team of healthcare providers and system planners caring for persons with an acute stroke or transient ischemic attack. These recommendations are a timely opportunity to reassess current processes to ensure efficient access to acute stroke diagnostics, treatments, and management strategies, proven to reduce mortality and morbidity. The topics covered include prehospital care, emergency department care, intravenous thrombolysis and endovascular thrombectomy (EVT), prevention and management of inhospital complications, vascular risk factor reduction, early rehabilitation, and end-of-life care. These recommendations pertain primarily to an acute ischemic vascular event. Notable changes in the 7th edition include recommendations pertaining the use of tenecteplase, thrombolysis as a bridging therapy prior to mechanical thrombectomy, dual antiplatelet therapy for stroke prevention, the management of symptomatic intracerebral hemorrhage following thrombolysis, acute stroke imaging, care of patients undergoing EVT, medical assistance in dying, and virtual stroke care. An explicit effort was made to address sex and gender differences wherever possible. The theme of the 7th edition of the CSBPR is building connections to optimize individual outcomes, recognizing that many people who present with acute stroke often also have multiple comorbid conditions, are medically more complex, and require a coordinated interdisciplinary approach for optimal recovery. Additional materials to support timely implementation and quality monitoring of these recommendations are available at www.strokebestpractices.ca.

T cells and orbital connective tissue in endocrine orbitopathy

In order to analyse the immunological changes in patients with endocrine orbitopathy (EO) the antigenic character of orbital connective tissue was studied. Counter-stimulation assays of patients' lymphocytes with autologous retrobulbar fibroblasts resulted in a markedly increased lymphocyte proliferation in comparison to incubation with retrobulbar control fibroblasts. Proliferation tests of retrobulbar T cell lines showed significant responses to autologous retro-orbital connective tissue proteins, with molecular weights of 6-10 kD and 19-26 kD. Phenotypic analysis of orbital T cell lines indicates that they consisted predominantly of CD4+ cells. Hyaluronic acid production of orbital fibro blasts following co-cultivation with lymphocytes of EO patients or controls revealed a threefold increased synthesis in patients with EO. Furthermore, distribution pattern of orbital extracellular matrix glycosaminoglycans (GAG) differs in EO patients in comparison to controls. The results suggest the presence of autoreactive T cells directed against antigens of orbital fibroblasts, whose stimulation results in an augmented GAG synthesis in patients with EO.

The Uromodulin C744G mutation causes MCKD2 and FJHN in children and adults and may be due to a possible founder effect

Autosomal dominant medullary cystic kidney disease type 2 (MCKD2) is a tubulo-in terstitial nephropathy that causes renal salt wasting, hyperuricemia, gout, and end-stage renal failure in the fifth decade of life. This disorder was described to have an age of onset between the age of 20-30 years or even later. Mutations in the Uromodulin (UMOD) gene were published in patients with familial juvenile hyperuricemic nephropathy (FJHN) and MCKD2. Clinical data and blood samples of 16 affected individuals from 11 different kindreds were collected. Mutational analysis of the UMOD gene was performed by exon polymerase chain reaction (PCR) and direct sequencing. We found the heterozygous C744G (Cys248Trp) mutation, which was originally published by our group, in an additional four kindreds from Europe and Turkey. Age of onset ranged from 3 years to 39 years. The phenotype showed a variety of symptoms such as urinary concentration defect, vesicoureteral reflux, urinary tract infections, hyperuricemia, hypertension, proteinuria, and renal hypoplasia. Haplotype analysis showed cosegragation with the phenotype in all eight affected individuals indicating that the C744G mutation may be due to a founder effect. Moreover, we describe a novel T229G (Cys77Gly) mutation in two affecteds of one kindred. Three of the affected individuals were younger than 10 years at the onset of MCKD2/FJHN. Symptoms include recurrent urinary tract infections compatible with the published phenotype of the Umod knockout mouse model. This emphasizes that MCKD2 is not just a disease of the young adult but is also relevant for children.

Barttin is a Cl- channel beta-subunit crucial for renal Cl- reabsorption and inner ear K+ secretion

Renal salt loss in Bartter's syndrome is caused by impaired transepithelial transport in the loop of Henle. Sodium chloride is taken up apically by the combined activity of NKCC2 (Na+-K--2Cl- cotransporters) and ROMK potassium channels. Chloride ions exit from the cell through basolateral ClC-Kb chloride channels. Mutations in the three corresponding genes have been identified that correspond to Bartter's syndrome types 1-3. The gene encoding the integral membrane protein barttin is mutated in a form of Bartter's syndrome that is associated with congenital deafness and renal failure. Here we show that barttin acts as an essential beta-subunit for ClC-Ka and ClC-Kb chloride channels, with which it colocalizes in basolateral membranes of renal tubules and of potassium-secreting epithelia of the inner ear. Disease-causing mutations in either ClC-Kb or barttin compromise currents through heteromeric channels. Currents can be stimulated further by mutating a proline-tyrosine (PY) motif on barttin. This work describes the first known beta-subunit for CLC chloride channels and reveals that heteromers formed by ClC-K and barttin are crucial for renal salt reabsorption and potassium recycling in the inner ear.

Mutation of BSND causes Bartter syndrome with sensorineural deafness and kidney failure

Antenatal Bartter syndrome (aBS) comprises a heterogeneous group of autosomal recessive salt-losing nephropathies. Identification of three genes that code for renal transporters and channels as responsible for aBS has resulted in new insights into renal salt handling, diuretic action and blood-pressure regulation. A gene locus of a fourth variant of aBS called BSND, which in contrast to the other forms is associated with sensorineural deafness (SND) and renal failure, has been mapped to chromosome 1p. We report here the identification by positional cloning, in a region not covered by the human genome sequencing projects, of a new gene, BSND, as the cause of BSND. We examined ten families with BSND and detected seven different mutations in BSND that probably result in loss of function. In accordance with the phenotype, BSND is expressed in the thin limb and the thick ascending limb of the loop of Henle in the kidney and in the dark cells of the inner ear. The gene encodes a hitherto unknown protein with two putative transmembrane alpha-helices and thus might function as a regulator for ion-transport proteins involved in aBS, or else as a new transporter or channel itself.

Improved strategy for molecular genetic diagnostics in juvenile nephronophthisis

Juvenile or type 1 nephronophthisis (NPH1), an autosomal recessive cystic kidney disease, represents the most common genetic cause of end-stage renal disease in the first two decades of life. Because the disease is caused by large homozygous deletions of the NPHP1 gene in approximately 66% of patients with nephronophthisis, molecular genetic testing offers a method for the definite diagnosis of NPH1 and avoids the invasive procedure of renal biopsy. We recently developed an algorithm for molecular genetic diagnosis of NPH1 that efficiently detects homozygous deletions. However, a major limitation remained for the detection of heterozygous deletions that cause NPH1 in combination with point mutations at the other NPHP1 allele. Because a partial sequence from the NPHP1 region recently became available through the Human Genome Projects, we exploited this information to develop novel polymorphic markers from this genetic region for the detection of heterozygous deletions of NPHP1, thus bridging the diagnostic gap. Five novel polymorphic microsatellites positioned within the large common NPHP1 deletion were generated. Two multiplex polymerase chain reaction sets using two and three polymorphic markers from the NPHP1 deletion region together with one positive control marker allowed four different diagnostic problems to be solved in one diagnostic setup: (1) detection of the classic homozygous deletion of NPH1, (2) detection of a rare smaller homozygous deletion of NPH1, (3) testing for a heterozygous deletion, and (4) potential exclusion of linkage to NPHP1. The newly generated multiplex marker sets will greatly enhance the efficacy of molecular diagnostics in NPH through improved detection of heterozygous deletions.

Refinement of the gene locus for autosomal dominant medullary cystic kidney disease type 1 (MCKD1) and construction of a physical and partial transcriptional map of the region

Autosomal dominant medullary cystic kidney disease (MCKD) is an adult onset tubulointerstitial nephropathy that leads to salt wasting and end-stage renal failure. A gene locus (MCKD1) has been mapped on chromosome 1q21. Here we report on a large MCKD1 family of British origin linked to the MCKD1 locus. Haplotype analysis performed with markers spanning the previously reported critical MCKD1 region allowed for the refinement of this interval to 4 cM by definition of D1S305 as a new proximal flanking marker. Furthermore, we constructed a yeast artificial chromosome, P1-related artificial chromosome, and bacterial artificial chromosome contig of this region, which is only sparsely covered by the Human Genome Sequencing Project. This enabled us to map numerous expressed sequence tags within the critical interval. This physical and partial transcriptional map of the MCKD1 region is a powerful tool for the identification of positional and functional candidate genes for MCKD1 and will help to identify the disease-causing gene.

Establishing an algorithm for molecular genetic diagnostics in 127 families with juvenile nephronophthisis

BACKGROUND

Juvenile nephronophthisis (NPH1), an autosomal recessive cystic disease of the kidney, represents the most common genetic cause of end-stage renal disease in the first two decades of life. On the basis of identification of the gene (NPHP1) defective in NPH1 and the presence of homozygous deletions of NPHP1 in the majority of NPH1 patients, molecular genetic diagnosis for NPH1 is now possible. Molecular genetic testing offers the only method for definite diagnosis of NPH1 and avoids invasive diagnostic measures like renal biopsy.

METHODS

We examined 127 families (204 patients) with the presumed diagnosis of NPH using molecular genetic diagnostic techniques. In 68 families, renal biopsy was performed and was consistent with NPH, and in 61 families, there was more than one affected child ("multiplex families").

RESULTS

In 74 families (115 patients), there was proof of the diagnosis of NPH1 by detection of a homozygous deletion of the NPHP1 gene, and in 5 families a heterozygous deletion in combination with a point mutation in NPHP1 was demonstrated. Furthermore, for 16 families, NPH1 was excluded with high likelihood by linkage analysis, and for 20 families by detection of heterozygosity for two newly identified polymorphic markers within the deletion region. In 5 of the remaining 12 families, which were noninformative for these markers, fluorescence in situ hybridization did not detect any further heterozygous deletions.

CONCLUSIONS

The diagnosis of NPH1 was proven by molecular genetic techniques in 62% of families with one or more children with the presumed diagnosis of NPH. We present evidence that there is a fourth locus for NPH, since only 6 of the 26 multiplex families in whom the diagnosis of NPH1 was excluded were compatible with linkage to other loci for NPH. On the basis of the presented data, we propose an algorithm for molecular genetic diagnostics in NPH.

Antiretroviral agents inhibit infection of human cells by porcine endogenous retroviruses

The efficacy of antiretroviral drugs against porcine endogenous retroviruses (PERV) that may be harbored in pig organs intended for transplantation was examined in human cells in vitro. The nucleoside analogs zidovudine and dideoxyinosine were found to effectively inhibit PERV replication.

Breeding of retroviruses by DNA shuffling for improved stability and processing yields

Manufacturing of retroviral vectors for gene therapy is complicated by the sensitivity of these viruses to stress forces during purification and concentration. To isolate viruses that are resistant to these manufacturing processes, we performed breeding of six ecotropic murine leukemia virus (MLV) strains by DNA shuffling. The envelope regions were shuffled to generate a recombinant library of 5 x 106 replication-competent retroviruses. This library was subjected to the concentration process three consecutive times, with amplification of the surviving viruses after each cycle. Several viral clones with greatly improved stabilities were isolated, with the best clone exhibiting no loss in titer under conditions that reduced the titers of the parental viruses by 30- to 100-fold. The envelopes of these resistant viruses differed in DNA and protein sequence, and all were complex chimeras derived from multiple parents. These studies demonstrate the utility of DNA shuffling in breeding viral strains with improved characteristics for gene therapy.

Infection by porcine endogenous retrovirus after islet xenotransplantation in SCID mice

Animal donors such as pigs could provide an alternative source of organs for transplantation. However, the promise of xenotransplantation is offset by the possible public health risk of a cross-species infection. All pigs contain several copies of porcine endogenous retroviruses (PERV), and at least three variants of PERV can infect human cell lines in vitro in co-culture, infectivity and pseudotyping experiments. Thus, if xenotransplantation of pig tissues results in PERV viral replication, there is a risk of spreading and adaptation of this retrovirus to the human host. C-type retroviruses related to PERV are associated with malignancies of haematopoietic lineage cells in their natural hosts. Here we show that pig pancreatic islets produce PERV and can infect human cells in culture. After transplantation into NOD/SCID (non-obese diabetic, severe combined immunodeficiency) mice, we detect ongoing viral expression and several tissue compartments become infected. This is the first evidence that PERV is transcriptionally active and infectious cross-species in vivo after transplantation of pig tissues. These results show that a concern for PERV infection risk associated with pig islet xenotransplantation in immunosuppressed human patients may be justified.

A deletion distinct from the classical homologous recombination of juvenile nephronophthisis type 1 (NPH1) allows exact molecular definition of deletion breakpoints

Juvenile nephronophthisis, an autosomal recessive cystic kidney disease, is the most common genetic cause of end-stage renal disease in children and young adults. We recently identified by positional cloning the causative gene, NPHP1. Its gene product nephrocystin may play a role in focal adhesion and adherens junction signaling. Approximately 80% of all patients with NPH1 carry large homozygous deletions, which contain the NPHP1 gene. These common deletions are positioned within a complex arrangement of large inverted and direct repeats, suggesting unequal recombination as a potential cause for their origin. In this study we have characterized the deletion breakpoints in a family with juvenile nephronophthisis that bears a unique maternal deletion of the NPHP1 gene, which is not the result of an event of homologous recombination. We molecularly characterized the centromeric and telomeric deletion breakpoints by extensive genomic sequencing, Southern blot analysis, and cloning and sequencing of the junction fragment. We were able to exactly localize the breakpoints at the position of two guanines. The centromeric breakpoint was positioned within intron 2 of the NPHP1 gene 360 bp downstream of the 5' end of a complete LINE-1 element. Multiple topoisomerase I and II consensus sequences were found at the breakpoint sites, suggesting the involvement of topoisomerase II in the deletion mechanism. These findings provide the first data on a potential mechanism for a deletion of the NPHP1 gene, that most likely is not the result of an event of homologous recombination and thereby distinct from the known common deletions.

Molecular cloning of the critical region for glomerulopathy with fibronectin deposits (GFND) and evaluation of candidate genes

Glomerulopathy with fibronectin deposits (GFND, MIM 601894) is an autosomal dominant kidney disease that leads to terminal renal failure at a median age of 47 years. It represents a distinct entity of membranoproliferative glomerulonephritis (MPGN) type III and is characterized by the unique feature of massive glomerular deposits of fibronectin. We have recently localized a gene locus for GFND to human chromosome 1q32 by total genome linkage analysis in a large kindred, within a 4.1-cM critical interval between markers D1S2872 and D1S2891. This interval contains a cluster of genes for "regulators of complement activation" (RCA), which represent strong candidates for GFND. To identify positional candidate genes for GFND within the critical genetic interval, we here report the cloning of the entire critical GFND region in a complete YAC and partial PAC contig. We constructed a high-resolution transcriptional map, thereby defining positional and functional candidate genes for the disease. To evaluate their role in GFND, we performed functional studies on RCA proteins in GFND patients from the large kindred, as well as mutational analysis of the genes for complement receptor-2 (CR2), membrane cofactor protein (MCP), and decay accelerating factor (DAF). Although no loss-of-function mutation has been identified as yet, these data provide a basis for the examination of candidate genes for GFND and other genes for MPGN, which localize to the vicinity of the GFND region.

Children with ocular motor apraxia type Cogan carry deletions in the gene (NPHP1) for juvenile nephronophthisis

Congenital ocular motor apraxia type Cogan is characterized by impairment of horizontal voluntary eye movements, ocular attraction movements, and optokinetic nystagmus. Two patients with congenital ocular motor apraxia type Cogan exhibited a newly recognized association with nephronophthisis type 1, an autosomal recessive kidney disease. Both patients possess large deletions of the NPHP1 gene. The deletion occurred on both chromosomes 2q13 in one patient and heterozygously in combination with a point mutation of the NPHP1 gene in the other. The findings will help to elucidate the pathogenetic processes involved.

Development of a competitive PCR method for in vitro and in vivo quantification of herpes simplex virus thymidine kinase and neomycin resistance-expressing cells used in a clinical trial

The aim of this study was to set up a sensitive and specific method to quantify the number of gene-modified cells in a gene therapy clinical trial currently underway at our institution. This trial involves the use of retrovirally transduced allogeneic T cells expressing the herpes simplex-1 thymidine kinase (HSV-TK) and neomycin-phosphotransferase (NeoR) resistance gene. Quantification by competitive PCR was performed, with two homologous internal standards (deltaTK, deltaNeoR), 30 bp shorter than the target sequences (TK, NeoR), coupled to fluorescent laser-based detection. Assessment of the amplification systems procedures was carried out for each sequence. The 30-bp deletion did not affect the amplification efficiency significantly. Determination of the plateau phase of both amplified sequences demonstrated that each sample must be quantified during the predetermined exponential phase. Finally, a blinded study of a transduced cell dilutions panel validated the overall methodology. The competitive PCR was applied to quantification of the retroviral transduction process by quantifying the NeoR gene in transduced PBMC samples (prior to G418 selection) from 18 donors in our clinical trial. A mean transduction efficiency of 9.78% +/- 1.37% was observed. We also quantified TK-expressing donor transgenic T cells in a murine GvHD model. Results demonstrated on initial expansion of donor HSV-TK- expression T cells as well as a significant ganciclovir (GCV)-induced decrease correlated with the number of circulating gene-modified T cells. Therefore, we have developed an efficient gene quantification tool that should be useful for in vivo monitoring of gene-modified cells.

An intelligent diabetes software prototype: predicting blood glucose levels and recommending regimen changes

Maintaining optimal blood glucose (BG) control is difficult for type 1 diabetes mellitus (T1DM) patients when typical daily regimens of food, insulin and exercise are altered. Artificial intelligence (AI) systems consisting of treatment algorithms calibrated through large datasets of patient specific information may offer a solution. Such a system can predict BG level changes resulting from regimen disturbances and recommend regimen changes for compensation. A software prototype based on neural network, fuzzy logic, and expert system concepts was developed and evaluated to determine feasibility and efficacy of a patient specific prediction model. BG data are the primary driver for adapting existing functions to patient specific prediction algorithms. Mean absolute percent error (MAPE) between actual and predicted BG values from inputs of daily insulin, food, and exercise information for an T1DM test subject was 10.5% using a calibrated model. The prototype is limited by the requirement for a rigid testing schedule, human error and situational circumstances such as alcohol consumption, illness, infection, stress, and significant hormonal imbalances. No significant conclusions regarding model validity can be drawn due to limited evaluation process and subject sample size, although the prototype has demonstrated viability as a learning tool for diabetes patients. Increased impetus for further development of this prototype and similar AI models may materialize when more effective diagnostic and data capture tools become available to reduce testing and improve accuracy of the model with more input data.

Efficacy of antiretroviral agents against murine replication-competent retrovirus infection in human cells

Retroviral vectors for gene therapy are designed to minimize the occurrence of replication-competent retrovirus (RCR); nonetheless, it is possible that a vector-derived RCR could establish an infection in a patient. Since the efficacy of antiretroviral agents can be impacted by interactions between virus, host cell, and drug, five commonly used antiretroviral drugs were evaluated for their abilities to inhibit the replication of a murine leukemia virus (MLV)-derived RCR in human cells. The results obtained indicate that the combination of nucleoside analogs zidovudine and dideoxyinosine with the protease inhibitor indinavir effectively inhibits MLV-derived RCR replication in three human cell lines. In addition, MLV-derived RCR was found to be inherently resistant to the nucleoside analogs lamivudine and stavudine, suggesting that mutations conferring resistance to nucleoside analogs in human immunodeficiency virus type 1 have the same effect even in an alternative viral backbone.

In vitro analysis of transformation potential associated with retroviral vector insertions

While replication-defective retroviral vectors provide excellent vehicles for the long-term expression of therapeutic genes, they also harbor the potential to induce undesired genetic changes by random insertions into the host genome. The rate of insertional mutagenesis for retroviral vectors has been determined in several different assay systems; however, the rate at which such events induce cellular transformation has not been directly determined. Such measurements are critical to determining the actual risk of carcinogenesis resulting from retroviral gene therapy. In this study, the ability of a replication-defective retroviral vector, GlnBgSvNa, to induce cellular transformation in the BALB/c-3T3 in vitro transformation assay was assessed. The transformation frequency observed in vector-transduced BALB/c-3T3 cells, which contained one to six copies of integrated provirus, was not significantly different from that of untreated control cells. The finding that GlnBgSvNa was nontransforming in this assay indicates that the rate of transformation induced by retroviral insertions is less than the spontaneous rate of cellular transformation by BALB/c-3T3 cells, or less than 1.1 x 10(-5). These results are the first to define an upper limit for the rate of transformation induced by retroviral vectors.

Search for cross-species transmission of porcine endogenous retrovirus in patients treated with living pig tissue. The XEN 111 Study Group

Pig organs may offer a solution to the shortage of human donor organs for transplantation, but concerns remain about possible cross-species transmission of porcine endogenous retrovirus (PERV). Samples were collected from 160 patients who had been treated with various living pig tissues up to 12 years earlier. Reverse transcription-polymerase chain reaction (RT-PCR) and protein immunoblot analyses were performed on serum from all 160 patients. No viremia was detected in any patient. Peripheral blood mononuclear cells from 159 of the patients were analyzed by PCR using PERV-specific primers. No PERV infection was detected in any of the patients from whom sufficient DNA was extracted to allow complete PCR analysis (97 percent of the patients). Persistent microchimerism (presence of donor cells in the recipient) was observed in 23 patients for up to 8.5 years.

Distribution of retroviral vectors and vector producer cells using two routes of administration in rats

The clinical use of retroviral vector producer cells (VPCs) to deliver retroviral vectors efficiently to target cells has been investigated as a method to increase efficiency of gene delivery, presumably as a result of continued vector production in vivo. Studies were conducted in rats to evaluate the distribution of vector to distal organs and tissues as measured by transduction. Rats were treated with two doses of VPCs using two routes of administration: (1) subcutaneous injection, chosen to maximize both the dose and exposure of animals, thereby enabling identification of potential target organs under worst-case conditions; and (2) direct injection into brain parenchyma, chosen to mimic the intended clinical route of administration and provide an estimate of risk to patients receiving this therapy. Twelve organs or tissues were collected 7 days after administration of VPCs and analyzed by PCR for the presence of vector and vector producer cell sequences. Vector was detected most frequently at the site of injection by either route of administration. Less frequently, vector was detected in draining lymph nodes at the higher dose only using either route of injection. Single specimens of lung and contralateral skin were positive for vector following subcutaneous administration only. Vector was detected in gonadal tissue from a single low-dose male following subcutaneous administration, but this finding was not reproduced in any high-dose male or any males injected intracerebrally. In contrast, VPCs were detected only at the site of administration. The frequency of detection of VPCs 7 days after administration was higher when rats were injected by the intracerebral route. Based on these studies, gene transfer to distal organs or gonadal tissue following intracerebral administration of VPCs is not considered to be a risk to patients undergoing retroviral vector gene therapy for the treatment of brain cancer (glioblastoma multiforme; GBM).

Molecular evaluation of biopsy and autopsy specimens from patients receiving in vivo retroviral gene therapy

We used the polymerase chain reaction (PCR) to assay for the presence of retroviral vector and replication-competent retrovirus (RCR) in autopsy and biopsy specimens from patients who received inoculations of retroviral vector producer cells (VPCs) into brain tumors or apparently normal tissues surrounding resected tumors. The PCR assays were capable of detecting 1 or more proviral copies of vector or RCR in 500,000 cells. Of 113 patients treated in clinical trials between 1994 and 1997, autopsy specimens were available from 32 patients. Brain tumor biopsies were also available from 24 patients. A total of 346 specimens was analyzed. Vector DNA was detected in 55% of tumor samples and 22% of brain samples obtained from resection margins. In contrast, most of the nonbrain tissues were negative for vector DNA; only low levels (<0.03%) of vector sequence were detected in 6 of 240 (2.5%) nonbrain tissues. Vector DNA was not detected in gonadal tissues from 12 men and 10 women. More importantly, RCR was not detected in any of the 134 biopsy and autopsy tissues tested, including all brain tumor, brain, and gonadal specimens. These results comprise the largest data set on molecular analysis of autopsy specimens from patients receiving retroviral gene therapy and indicate that distribution of retroviral vectors following injection of high doses of VPCs is limited to the site of inoculation.

Analysis of orbital T cells in thyroid-associated ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) has a major effect on the two compartments of the retro-orbital (RO) space, leading to enlargement of the extraocular muscles and other RO tissues. T lymphocyte infiltration of RO tissue is a characteristic feature of TAO and there is current interest in whether these T cells are specifically and selectively reactive to RO tissue itself. We recently established 18 T cell lines (TCL) from RO adipose/connective tissue of six patients with severe TAO by using IL-2, anti-CD3 antibodies and irradiated autologous peripheral blood mononuclear cells (PBMC) to maintain the growth of T cells reactive to autologous RO tissue protein fractions. Here we report on the phenotype characteristics and cytokine gene expression profiles of these orbital TCL and on their immunoreactivity to the organ-specific thyroid antigens thyrotropin receptor (TSH-R), thyroidal peroxidase (TPO) and thyroglobulin (TG). Flow cytometry revealed that 10 TCL were predominantly of CD4+ phenotype, three being mostly CD8+ and five neither CD4+ nor CD8+. Analysis with reverse transcriptase-polymerase chain reaction (RT-PCR) of cytokine gene expression revealed both Th1- and Th2-like products in all TCL: IL-2 product (in 17 TCL), interferon-gamma (IFN-gamma) (n = 10), tumour necrosis factor-beta (TNF-beta) (n = 15), IL-4 (n = 12), IL-5 (n = 17), IL-6 (n = 13), TNF-alpha (n = 12) and IL-10 (n = 4). Reactivity to thyroid antigens was observed only in two TCL, the other 16 being uniformly unreactive. Although 10 out of 18 RO tissue-reactive TCL were predominantly CD4+ there were no significant relationships between TCL phenotype, cytokine gene profile, magnitude of reactivity to RO tissue protein or the (rare) occurrence of thyroid reactivity. The findings of both Th1- and Th2-like cytokine gene expression in all RO tissue-reactive TCL support the concept that TAO is a tissue-specific autoimmune disease, distinct immunologically from the thyroid, and involving both T cell and B cell autoimmune mechanisms in disease pathogenesis.

Biosafety monitoring of patients receiving intracerebral injections of murine retroviral vector producer cells

Patients with recurrent malignant brain cancer, who were receiving gene therapy by intracerebral injection of murine retroviral vector producer cells (VPCs), were monitored for the presence of replication-competent retrovirus (RCR). RCR sequences were not detected by polymerase chain reaction (PCR) in any of the 608 peripheral blood leukocyte (PBL) samples analyzed. Vector DNA sequences were detected transiently in PBL samples from a subset of 34 patients. Humoral immune responses to a retroviral core protein p30 and murine VPC were detected in some patients, most frequently in patients receiving repeated administrations of VPC. RCR was not detected in biological assays of PBLs from 41 patients who had either anti-retroviral antibodies in sera and/or vector DNA in PBLs. Our data suggest that in situ generation of RCR was not detected following intracerebral inoculation of VPCs in any of the 128 patients evaluated.

Therapy of malignant brain tumors by intratumoral implantation of retroviral vector-producing cells

Intratumoral implantation of murine cells modified to produce retroviral vectors containing the herpes simplex virus-thymidine kinase (HSV-TK) gene induces regression of experimental brain tumors in rodents after ganciclovir (GCV) administration. We evaluated this approach in 15 patients with progressive growth of recurrent malignant brain tumors. Antitumor activity was detected in five of the smaller tumors (1.4 +/- 0.5 ml). In situ hybridization for HSV-TK demonstrated survival of vector-producing cells (VPCs) at 7 days but indicated limited gene transfer to tumors, suggesting that indirect, "bystander," mechanisms provide local antitumor activity in human tumors. However, the response of only very small tumors in which a high density of vector-producing cells had been placed suggests that techniques to improve delivery and distribution of the therapeutic gene will need to be developed if clinical utility is to be achieved with this approach.

A novel gene encoding an SH3 domain protein is mutated in nephronophthisis type 1

Juvenile nephronophthisis (NPH), an autosomal recessive cystic kidney disease, is the primary genetic cause of chronic renal failure in children. About two thirds of patients with NPH carry a large homozygous deletion at the gene locus NPH1 on 2q13. We here identify a novel gene. NPHP1, which extends over most of this common deletion. The 4.5-kb transcript encodes a protein with an SH3 domain, which is highly conserved throughout evolution. The 11-kb interval between the 3' end of NPHP1 and an inverted repeat containing the distal deletion breakpoint was found to contain the first exon of a second gene, MALL. In patients with a hemizygous deletion of the NPH1 region, additional point mutations were found in NPHP1 but not in MALL.

HPLC glycosaminoglycan analysis in patients with Graves' disease

1. Orbital accumulation of hydrophilic, interstitial glycosaminoglycans (GAGs) and subsequent expansion of retrobulbar tissue lead to the clinical manifestation of exophthalmos in patients with Graves' eye disease. 2. A highly specific method to determine the concentration and biochemical composition of different GAGs was developed in order to obtain a sensitive test system for the activity of the disease. By means of this method, GAG excretion in 24 h urine collections of 56 patients and 21 controls was analysed by precipitation with cetylpyridinium chloride and potassium acetate in ethanol, followed by sequential enzymic hydrolysis with chondroitin AC lyase, chondroitin ABC lyase and hyaluronate lyase, with HPLC analysis of the resulting alpha, beta-unsaturated disaccharides by anion-exchange chromatography. 3. Concentrations of GAG, chondroitin sulphate A (CA), dermatan sulphate (DS) and hyaluronic acid (HA) were determined in patients and controls, with high recovery rates [72.2 +/- 5.3%, mean +/- SEM; detection limit, 4.2 micrograms/l (0.01 mumol/l)], revealing marked differences in urinary concentrations of total GAG and HA, as well as an elevation of CA in patients compared with controls. 4. Method sensitivity was 0.86 for patients with active Graves' eye disease, and 0.87 for patients with untreated ophthalmopathy, whereas specificity was 1.0 for patients with inactive disease. Patients with increased GAG concentration responded well to steroids and/or orbital irradiation (before therapy: GAG, 111.49 +/- 40.32; CA, 59.58 +/- 21.34; DS, 25.05 +/- 8.12; HA, 26.88 +/- 11.63 mg/24 h; during therapy: GAG, 54.22 +/- 10.94; CA, 20.52 +/- 4.58; DS, 17.65 +/- 3.46; HA, 16.05 +/- 3.69 mg/24 h), whereas GAG excretion increased markedly 2-3 months after stopping prednisone therapy in patients with still active eye disease (GAG, 109.9 +/- 10.51; CA, 63.8 +/- 7.34; DS, 24.1 +/- 5.07; HA, 22.0 +/- 6.28 mg/24 h). 5. This sensitive method determines the nature of renally excreted GAGs, reflecting the aberrant synthesis pattern of fibroblasts in patients with Graves' disease.

Diabetic microangiopathy and urinary glycosaminoglycans

Alterations in the metabolism of glycosaminoglycans (GAG) may play a role in the pathogenesis of diabetic-associated microangiopathy. Consequently, the relationship between diabetic nephropathy and retinopathy and urinary GAG distribution was assessed in 96 IDDM patients in comparison to 103 healthy controls. GAG concentration in 24h urine samples was determined by precipitation with cetylpyridinium chloride and potassium acetate in ethanol followed by a colorimetric test with carbazole. A marked difference (P = 0.0008) in urinary GAG excretion between patients (24.3 +/- 1.5 mg/24 h, mean +/- SEM) and controls (16.2 +/- 0.75 mg/24 h) could be detected. In patients with IDDM of longer duration, GAG excretion was increased (< or = 10 yr: 20.8 +/- 2.1 vs > 10 yr: 27.4 +/- 2.1 mg/24 h; P = 0.03). Furthermore, IDDM patients with class 4 nephropathy and retinopathy exhibited a markedly higher GAG excretion compared to those without nephropathy (33.1 +/- 3.0 vs 22.6 +/- 1.7 mg/24 h, P = 0.005) or retinopathy (29.7 +/- 2.8 vs 21.2 +/- 1.7 mg/24 h, P = 0.009). An increased urinary GAG concentration was detected in IDDM patients with albuminuria (> 300 mg/24 h: 29.9 +/- 3.3 vs < 30 mg/24 h: 23.0 +/- 1.7 mg/24 h; P = 0.048), proteinuria (> 0.5 g/24 h: 30.3 +/- 3.7 vs < 0.05 g/24 h: 22.7 +/- 1.6 mg/24 h) and in patients with augmented serum creatinine in comparison to those with normal values (> 0.12 mg/L: 34.9 +/- 2.3 vs < 0.12 mg/L: 22.4 +/- 1.6 mg/24 h; P = 0.01). The results demonstrate a close relationship renal GAG excretion and the presence of microangiopathy in IDDM patients.

Glycosaminoglycans in autoimmunity

Alteration of the distribution pattern and composition of glycosaminoglycans (GAG) and proteoglycans may play an important role in the development of autoimmune diseases. Recent experiments indicate that anti-DNA antibodies cross-reacting with hyaluronic acid, heparan sulphate and chondroitin sulphate are present in patients with systemic lupus erythematosus. Furthermore, elevated hyaluronic acid antibody levels correlating with the disease score have been found in the sera of patients with autoimmune thyroid disease in comparison to controls. In vitro, T lymphocytes from patients with this disease increased the production of hyaluronic acid by cultured human retro-orbital fibroblasts. Fibroblast stimulation, as well as elevated collagen and GAG production, could be shown in chicken cell lines which spontaneously develop an autoimmune syndrome analogous to human scleroderma. To analyse the structure and distribution pattern of different GAG compounds in the tissues and body fluids of patients with autoimmune diseases a highly specific HPLC method was developed, which revealed increased urinary chondroitin sulphate and dermatan sulphate concentrations in patients with autoimmune thyroid disease in comparison to controls, concentrations which were positively correlated with disease severity and disease activity. Furthermore, the renal GAG excretion in patients with autoimmune diabetes mellitus was studied, and markedly higher excretion in patients compared to healthy controls was found, which was correlated with the duration of the disease and diabetic late complications. Thus, GAG polysaccharides not only appear to play a major role in the pathogenesis of autoimmune diseases, but have been successfully introduced as an activity marker of the disease.

TSH receptor in endocrine autoimmunity

OBJECTIVE

The human thyrotropin receptor (hTSHR) is a potential common antigen in endocrine autoimmunity. Recently, some studies demonstrated transcripts for hTSHR or its components in the extrathyroidal tissue of patients with autoimmune thyroid disease (ATD), although others were unable to confirm these findings. In the present study we investigated orbital adipose/connective and muscle tissue as well as primary cell cultures of orbital fibroblasts and myoblasts from patients with thyroid and eye disease.

METHODS

The messenger ribonucleic acid (mRNA) of hTSHR was reverse transcribed and amplified by polymerase chain reaction (PCR). To evaluate the existence of a functional hTSHR in cultured orbital fibroblasts and muscle cells, the TSH-mediated metabolic activity of the cells was measured by tetrazolium assay.

RESULTS

We were unable to amplify the extracellular domain of hTSHR regardless of the material used. In contrast, transcripts of the transmembrane and intracellular domain of hTSHR were detectable in both crude retrobulbar tissue and primary cells cultures. The results of fibroblast amplification experiments were more successful than those with myoblasts. Furthermore, we were able to confirm that these transcripts of hTSHR can also be detected in the retro-ocular tissue of healthy persons. Independently of the TSH activity employed, no stimulation of fibroblasts or myoblasts was detected, even at higher TSH levels.

CONCLUSION

These data do not suggest that hTSHR is expressed in a functional form in orbital tissue. However, a part of the receptor could play a role in the pathogenesis of autoimmune eye disease as a non-functional but antigenic protein. Whether a common antigen in the thyroid and orbit is related to hTSHR has not been clarified yet.

Autoimmune endocrine ophthalmopathy and retrobulbar antigens

Endocrine Ophthalmopathy (EO) is based on autoimmune processes that lead to lymphocyte infiltration of the retrobulbar space. In this study, antigenic character of retrobulbar adipose, connective and muscle tissue as well as of cultured fibroblasts and myoblasts were examined. Samples were obtained from EO patients (n = 13, 8 fem., age 26-82 years, median 47 years) undergoing orbital decompression surgery. Retrobulbar and abdominal tissue from 7 controls (4 fem., 48 - 74 y) was investigated, too. Tissues were homogenized and the proteins were separated by SDS-PAGE according to molecular weight. In order to recover the separated proteins in soluble form, an electroelution technique was employed. Twenty-two separated soluble protein fractions were used as antigenic stimuli for autologous peripheral blood mononuclear cells (PBMC) separated by Ficoll gradient centrifugation. Subsequently, the proliferation of T cells was measured by [3H]-thymidine uptake. A marked T cell response to protein fractions with molecular weight of 6 - 10 kD and 19 - 26 kD was detected (p < 0.001). These autoantigens were found readily reproducible in adipose tissue in 8 out of 9 EO patients, stimulation index (SI) to antigen 6 - 10 kD 29 +/- 4.6 (mean +/- SEM); 19 - 26 kD 5 +/- 1.4 and in 3 out of 4 patients using retrobulbar eye muscle tissue (SI: 6 - 10 kD 23 +/- 4.2; 19 - 26 kD 6 +/- 2). Using the proteins of cultured fibroblasts as antigen, the autologous PBMC from 2 out of 4 tested EO-patients also responded (SI: 7 +/- 2; 4 +/- 1.4). Testing cultured retrobulbar myoblasts of an EO patient, a response to the 19 - 26 kD antigen was found only (SI: 8.0). In response to retrobulbar or muscle proteins, PBMC of 2 controls showed also a higher proliferation rate (SI: 16 +/- 3.5; 13 +/- 2.8), whereas, a response to abdominal adipose or muscle proteins (4 controls) was never found. Thus, two orbital antigens reacting with autologous T cells could be demonstrated and may play an important role in the immunopathogenesis of EO. According to these findings, retrobulbar fibroblast antigens are most likely the main T cell targets.

An improved retroviral vector encoding the herpes simplex virus thymidine kinase gene increases antitumor efficacy in vivo

Brain tumors have been treated clinically by intratumoral injection of cells that produce retroviral vectors encoding the herpes simplex virus thymidine kinase (HSV-TK) gene followed by systemic administration of the antiviral drug ganciclovir. In vitro and in vivo comparisons of two different HSV-TK vector producer clones, which were made using standard transfection and transinfection techniques, were conducted. The two clones, PA317/G1TkSvNa.53 (TK.53) and PA317/G1Tk1SvNa.7 (TK1.7), both used in clinical trials, differ with respect to sequences 3' to the HSV-TK stop codon. The retroviral construct used to generate the TK.53 vector producer cell clone contains an open reading frame encoding a portion of the herpes simplex virus glycoprotein H (gH), a potential polyadenylation site and a putative splice site in this region. These sequences were removed from the retroviral construct used to create the TK1.7 vector producer cell clone. Supernatants obtained from TK1.7 vector producer cells had 100- to 1000-fold higher titers (G418 or HAT) than did corresponding supernatants from TK.53 vector producer cells. A murine subcutaneous tumor model was used to assess transduction efficiency and antitumor activity of each vector producer cell clone. In vivo tumor cell transduction was 13- to 18-fold more efficient with TK1.7 cells as compared with TK.53 cells at equivalent doses. Complete tumor ablation was achieved using a 10-fold lower dose of TK1.7 cells as compared with TK.53 cells. These results suggest that TK1.7 cells combined with ganciclovir may provide a more potent antitumor response in humans.

Transduction of rIL-2 expanded CD4+ and CD8+ ovarian TIL-derived T cell lines with the G1Na (neor) replication-deficient retroviral vector

We have expanded ovarian tumor-infiltrating lymphocytes (TIL) in low concentrations of recombinant interleukin-2 (rIL-2) to conduct intraperitoneal adoptive immunotherapy trials in patients with ovarian cancer. We have previously demonstrated that certain T cell lines and clones derived from ovarian TIL exhibit in vitro autologous tumor-specific cytotoxicity and/or cytokine production (interferon-gamma, tumor necrosis factor-alpha) preferentially in response to autologous tumor cells. Studies that utilize a marker gene introduced into the DNA of TIL can provide useful information on specific uptake or localization of TIL at tumor sites and on the survival of TIL in vivo. We have conducted a series of preclinical experiments in which we have successfully transfected TIL with G1Na, which encodes the gene for neomycin phosphotransferase (neoR). NeoR was detected in at least 10% of CD8+ cells (mean = 10.4%) and between 2.5 and 20% of CD4+ TIL (mean = 8.5%). Transduction of ovarian TIL with G1Na caused no substantial changes to the T cell phenotypes or in vitro cytotoxicities against ovarian and hematogenous tumor cell targets, or on the rIL-2 requirements of TIL for growth and proliferation. In addition, the intact G1Na provirus in transduced TIL cells was rescuable by replication-competent retrovirus and was transferred into the genome of NIH-3T3 fibroblasts, which were rendered resistant to G418. An enhanced polymerase chain reaction (PCR) procedure utilizing detection by ethidium bromide staining was developed. The enhanced PCR detected 1 in 100,000 neoR-labeled cells. Furthermore, detection of the G1Na genome in transduced TIL by in situ hybridization with an RNA probe provided evidence for expression of the neoR gene in transduced TIL. Results obtained from these studies suggest that ovarian TIL-derived T cell lines transduced with the neoR gene post infection with the G1Na retroviral vector can be utilized to examine the in vivo trafficking pattern of ovarian TIL-derived T cell lines expanded in low concentrations of rIL-2 and their survival.

Characterization of a replication-competent retrovirus resulting from recombination of packaging and vector sequences

A replication-competent retrovirus (RCR) was detected by S+/L- assays in three lots of retroviral vector G1Na that were harvested on consecutive days from a single culture of PA317/G1Na producer cells. Using a number of retrovirus-specific primer pairs, it was shown that this RCR was a novel recombinant created by exchanges between G1Na and helper sequence pPAM3 and was not an existing RCR introduced by cross-contamination. Sequencing of clones of DNA amplified in six independent PCR reactions confirmed that the 3' portion of this RCR was composed of retroviral envelope sequences unique to pPAM3 joined to a 3' long terminal repeat (LTR) unique to G1Na. Comparison of pPAM3 and G1Na sequences at the site corresponding to this junction revealed a short segment of patchy nucleotide identity (8 out of 10 bp), suggesting that these helper and vector sequences were joined by homologous recombination. Generation of RCR by exchanges between helper and vector sequences underscores the necessity of testing by efficient methods all retroviral vectors for the presence of RCR before their use. Production of 171 lots (855 liters) of various retroviral vectors that were free of RCR, including 42 lots of G1Na, however, indicates that the combination of exchanges required to generate an RCR are infrequent in this system.

Improved methods of retroviral vector transduction and production for gene therapy

To facilitate clinical applications of retroviral-mediated human gene transfer, retroviral vectors must be of high titer and free of detectable replication-competent retroviruses. The purpose of this study was to optimize methods of retroviral vector production and transduction. Studies were conducted using 22 retroviral vector producer cell lines. Inactivation of retroviral vectors was greater at 37 degrees C than at 32 degrees C. A 5- to 15-fold increase of vectors was produced at 32 degrees C compared to 37 degrees C; the vector increase at 34 degrees C was intermediate. For example, PA317/G1Na.40 grew to a titer of 1.8 x 10(7) cfu/ml at 32 degrees C, compared to 5.0 x 10(5) cfu/ml at 37 degrees C. The production of retroviral vectors was scalable achieving similar results in flasks, roller bottles, or a CellCube Bioreactor. Retroviral vectors were concentrated 15-24 times with vector recovery ranging from 91 to 96% in a Pellicon tangential flow filtration system. Retroviral supernatants were successfully lyophilized. The combination of glucose or sorbitol with gelatin resulted in recovery rates of 64-83%. In studies on transduction by retroviral vectors, centrifugation of vector supernatants onto target cells significantly increased transduction efficiency as measured by vector titration for G418 resistance, fluorescence-activated cell sorting (FACS), and polymerase chain reaction (PCR) analyses. The combination of the above methods has significantly increased the growth and transduction by this vector system.

Cellular immunity and retrobulbar fibroblasts in Graves' ophthalmopathy

In Graves' ophthalmopathy (GO), retrobulbar connective tissue is infiltrated by T cells whose role in the pathogenesis of the disease was investigated in the present work. The aims included firstly to characterize subsets of blood lymphocytes and of sessile lymphocytes cloned from a retroorbital tissue specimen. Second, in counterstimulation assays, the ability of patients' T cells to influence cultivated retrobulbar fibroblasts and in turn the enhancement of lymphocyte proliferation by retrobulbar fibroblasts was investigated. Blood lymphocytes of 16 GO patients and 12 controls isolated by density gradient centrifugation and retrobulbar fibroblasts obtained from orbital decompression were alternately exposed to irradiation of 4000 rad (to suppress proliferation of either cell type), then cocultivated for 48 h. Subsequently, the cells (250,000 lymphocytes, 5000 retrobulbar fibroblasts) were incubated with [3H]thymidine for 24 h. A stimulation index representing the degree of proliferation in comparison with a control was determined. Screening of 62 retrobulbar lymphocyte clones by cell-ELISA revealed a CD4/CD8 ratio of 8.2, contrasting with a normal ratio of 2.1 in peripheral lymphocytes (as obtained by FACS analysis). Incubation of patient's lymphocytes with autologous retrobulbar fibroblasts resulted in a markedly elevated stimulation index (9.7) compared to incubation of lymphocytes with retrobulbar fibroblasts from controls (2.5). In another assay, the degree of stimulation amounted to 2.2 vs. -0.8. Retrobulbar fibroblasts were stimulated twice as much by lymphocytes of the same patient compared to retrobulbar fibroblasts from controls. The autologous reactions demonstrated suggest the presence of autoreactive T lymphocytes in GO patients directed against retrobulbar fibroblasts, which, in addition, are stimulated by these lymphocytes.

Glycosaminoglycan antibodies in endocrine ophthalmopathy

An increased accumulation of glycosaminoglycans (GAG) in the orbita has been reported in endocrine ophthalmopathy (EO). In this study we investigated whether antibodies directed against GAG are present in the sera of 52 EO patients and 47 healthy controls. Three out of 52 patients exhibited low titers of antinuclear antibodies and all patients were negative for antibodies against extractable nuclear antigens. Isotype IgG antibodies were detected by means of an ELISA using hyaluronic acid and dermatan sulfate as antigens. Values were expressed as optical density at 405 nm. In comparison to the control group (0.445, 0.364, 0.588; median, 25th, 75th percentile) significantly (p < 0.001) higher hyaluronic acid antibody levels were found in EO patients (0.626, 0.473, 0.801). Untreated patients had significantly higher hyaluronic acid antibody values compared to controls (0.770 vs 0.437, median, p < 0.005). Thyroid status or antithyroid treatment did not influence binding of hyaluronic acid antibodies. When screening for dermatan sulfate antibodies no such difference could be observed between patients and controls. Thus, the detection of GAG antibodies in EO patients emphasizes the important role of glycosaminoglycans in the pathogenesis of thyroid eye disease.

In vitro synthesis of glycosaminoglycans in endocrine ophthalmopathy

The effects of humoral and cell-mediated immunity on the glycosaminoglycan synthesis of retrobulbar fibroblasts was evaluated in patients with endocrine ophthalmopathy. After incubation with IgG and sera, secreted glycosaminoglycans, radiolabeled with D-6-3H-glucosamine and 35sulfate, were precipitated with cetylpyridinium chloride and ethanol. Hyaluronic acid synthesis of human retrobulbar fibroblasts after incubation with sera and IgG and after co-culture with lymphocytes was assessed by means of a radiometric test. Patients' IgG, compared to controls', accounted for a higher secretory stimulation of porcine retrobulbar fibroblasts (as measured by cetylpyridinium chloride precipitation) after 24 and 48 h. Contrasting with 24 h incubation time, glycosaminoglycan values after 48 h were increased two to threefold. Patients' and controls' sera caused earlier and stronger, yet indistinguishable glycosaminoglycan production. Non-sulfated hyaluronic acid was the preponderant glycosaminoglycan secreted into the media by retrobulbar fibroblasts. As assessed with the radiometric test, incubation with patients' and controls' sera and IgG did not reveal a significant difference in stimulating the hyaluronic synthesis of patients' and controls' retrobulbar fibroblasts. When measuring the hyaluronic acid synthesis of controls' and patients' retrobulbar fibroblasts after co-cultivation of lymphocytes, however, patients' lymphocytes had a marked ability to increase the hyaluronic acid concentration compared to controls' lymphocytes. The hyaluronic acid concentration after incubation of a patient's retrobulbar fibroblasts with autologous lymphocytes was markedly more elevated than the intrinsic hyaluronic acid production of retrobulbar fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)

Humoral immunity and retrobulbar fibroblasts in endocrine ophthalmopathy

The exact role of retrobulbar fibroblasts in the immunopathogenesis of endocrine ophthalmopathy still remains to be elucidated. To evaluate the in vitro influence of humoral immunity on retrobulbar fibroblasts, the effects of immunoglobulin G as well as of the sera of 50 euthyroid patients with endocrine ophthalmopathy and 30 controls on both porcine and human (patients' and controls') retrobulbar fibroblasts were measured by means of several assays: a colorimetric test involving a heterocyclic chemical, a tetrazolium bromide, was applied to quantify the activity of mitochondrial dehydrogenases; the incorporation of 3H-thymidine was determined as a sensitive parameter for cell proliferation, and an enzyme-linked immunosorbent assay was to reveal specific binding of antibodies to the cells. There was consistently no significant difference between patients' (untreated or treated) and controls' IgG to bind to, to activate or to stimulate the proliferation of porcine and human (patients and controls) retrobulbar fibroblasts. The effects of patients' heat-inactivated and non-inactivated sera were indistinguishable from those of the controls. Incubation of autologous sera, however, led to an activation of retrobulbar fibroblasts which was both higher than the median caused by the patients' group and that engendered by incubation of autologous IgG. Yet, a significant role that humoral immunity might play directly on retrobulbar fibroblasts could not be detected in the experiments conducted in this study.

Glycosaminoglycans in thyroid-associated ophthalmopathy

Glycosaminoglycan (GAG) accumulation in the retrobulbar space of patients with thyroid-associated ophthalmopathy (TAO) has been documented in a number of immunohistochemical studies. In order to gain further insight into possible immunopathogenic mechanisms, the influence of humoral immunity on retrobulbar fibroblasts (RF) as GAG producing cells as well as on GAGs themselves was investigated. The effect of lymphocytes on hyaluronic acid (HA) synthesis of RF as well as in turn the influence of RF on lymphocytes were evaluated. In search of methods which would facilitate management of patients with TAO and allow assessment of disease activity, GAGs were determined in both urine and plasma. Immunoglobulin G (IgG) of patients with TAO were found to markedly stimulate the 3H-GAG secretion of RF. Patients with TAO exhibited significantly greater antibody values directed against HA than controls. Preliminary results concerning the influence of lymphocytes on RF indicate a tendency for patients' lymphocytes to increase the synthesis of HA. Furthermore, these lymphocytes in turn were stimulated more by irradiated autologous RF than by irradiated heterologous RF. Urine and plasma GAG determination proved to be suitable for the routine assessment of disease activity and outcome of therapy. In conclusion, GAGs seem to play an important role in the pathogenesis of the disease and their measurement may provide aid to the endocrinological evaluation of patients with TAO.