Autophagy and Mitophagy-Related Pathways at the Crossroads of Genetic Pathways Involved in Familial Sarcoidosis and Host-Pathogen Interactions Induced by Coronaviruses.

Sarcoidosis is a multisystem disease characterized by the development and accumulation of granulomas, the hallmark of an inflammatory process induced by environmental and/or infectious and or genetic factors. This auto-inflammatory disease mainly affects the lungs, the gateway to environmental aggressions and viral infections. We have shown previously that genetic predisposition to sarcoidosis occurring in familial cases is related to a large spectrum of pathogenic variants with, however, a clustering around mTOR (mammalian Target Of Rapamycin)-related pathways and autophagy regulation. The context of the COVID-19 pandemic led us to evaluate whether such genetic defects may increase the risk of a severe course of SARS-CoV2 infection in patients with sarcoidosis. We extended a whole exome screening to 13 families predisposed to sarcoidosis and crossed the genes sharing mutations with the list of genes involved in the SARS-CoV2 host-pathogen protein-protein interactome. A similar analysis protocol was applied to a series of 100 healthy individuals. Using ENRICH.R, a comprehensive gene set enrichment web server, we identified the functional pathways represented in the set of genes carrying deleterious mutations and confirmed the overrepresentation of autophagy- and mitophagy-related functions in familial cases of sarcoidosis. The same protocol was applied to the set of genes common to sarcoidosis and the SARS-CoV2-host interactome and found a significant enrichment of genes related to mitochondrial factors involved in autophagy, mitophagy, and RIG-I-like (Retinoic Acid Inducible Gene 1) Receptor antiviral response signaling. From these results, we discuss the hypothesis according to which sarcoidosis is a model for studying genetic abnormalities associated with host response to viral infections as a consequence of defects in autophagy and mitophagy processes.

Chitotriosidase: a biomarker of activity and severity in patients with sarcoidosis.

BACKGROUND: Serum chitotriosidase is a promising biomarker that has shown high specificity and sensitivity in patients with sarcoidosis. The aim of this study was to investigate correlations between serum chitotriosidase, clinical phenotypes, disease localizations and different radiological lung involvement and to identify clinical features associated with over-expression of chitotriosidase in a large cohort of sarcoidosis patients. METHODS: Chitotriosidase activity was evaluated in a population of 694 consecutive patients (males 39%, age 55.8 ± 12.8 years). Clinical and respiratory functional characteristics, Clinical Outcome Scale (COS) classification, clinical phenotypes proposed by the GenPhenResA project, and radiological assessment, including CT scan, were collected. Serum sampling and clinical and functional assessments at follow-up were also included. RESULTS: Significantly higher chitotriosidase activity was observed in sarcoidosis patients than in healthy controls (p < 0.0001). Evidence of lung fibrosis with reticular abnormalities and traction bronchiectasis at High resolution CT, presence of multiple extrapulmonary sarcoid localizations and increased 24-h urinary excretion of calcium were associated with significantly higher chitotriosidase activity (p < 0.005). Patients with remitted or minimal disease had lower values of chitotriosidase than patients with persistent disease. At follow-up, patients who required an increase in steroid dose showed an increase in its activity. CONCLUSIONS: Chitotriosidase is a reliable biomarker of sarcoidosis. It is increased in patients with sarcoidosis correlating with disease activity, severity and multiorgan dissemination. Steroid therapy tended to reduce chitotriosidase expression, however it responded in cases of disease relapse.

Serum Angiotensin-Converting Enzyme Has a High Negative Predictive Value in the Investigation for Systemic Sarcoidosis.

PURPOSE: To examine whether measurement of serum angiotensin-converting enzyme (ACE) is useful in diagnosing sarcoidosis in undifferentiated uveitis. DESIGN: Evaluation of a diagnostic test. METHODS: Data collection was performed from 1035 consecutive subjects presenting with uveitis to Moorfields Eye Hospital undergoing measurement of serum ACE as part of baseline investigations for underlying systemic disease. The main outcome measures were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of elevated serum ACE. RESULTS: Mean age of the sample was 41.7 years and 56.1% of subjects were female. Sarcoidosis was the underlying cause for the uveitis in 110 subjects (10.6%) and was more common in adults, female subjects, black subjects, and subjects with intermediate uveitis or panuveitis. ACE was elevated in 196 subjects (18.9%) and elevated levels were observed in 85 subjects eventually diagnosed with underlying sarcoidosis (true positive 77.3%) and in 111 subjects with an alternate diagnosis (false positive 12.0%). In adult subjects, sensitivity of serum ACE was 78.1%, specificity 90.0%, and PPV 43.6%, but the NPV was 97.0%. The test performed well, with area under curve (AUC) 0.897 (95% confidence interval [CI] 0.854-0.941). Serum ACE performed less well in distinguishing sarcoid uveitis in pediatric subjects, with sensitivity 60.0%, specificity 78.5%, and PPV 10.0%, but again NPV was high at 96.9% and AUC was 0.828 (95% CI 0.571-1.000). CONCLUSIONS: Serum ACE had a very high negative predictive value for sarcoid uveitis, eliminating the need for further screening tests in subjects with normal serum ACE, unless clinical suspicion was high.

Utility of angiotensin-converting enzyme activity in aqueous humor in the diagnosis of ocular sarcoidosis.

PURPOSE: Many studies include elevated activity of angiotensin-converting enzyme (ACE) in serum in sarcoidosis and in ocular sarcoidosis as well, but there are only a few analyzing ACE activities in aqueous humor. The aim of this study is to illuminate the diagnostic value of ACE in aqueous humor in patients with ocular sarcoidosis. METHODS: We analyzed twenty patients with ocular sarcoidosis and 18 patients with nonocular involvement. All patients have biopsy-positive sarcoidosis of the lungs and/or mediastinal lymph nodes. Blood samples for ACE serum levels were obtained from all patients. Aqueous humor samples were taken by paracentesis with a 25-gauge needle in local anesthesia. With appropriate statistical tests, we compared ACE activity in serum and aqueous humor in patients with and without ocular sarcoidosis. RESULTS: The majority of our patients with ocular sarcoidosis were female (12/20), also in the group with systemic sarcoidosis and without ocular involvement (12/6). Mean age of the whole analyzed group of sarcoidosis patients was 45 ± 6 years. There is no statistically significant difference in ACE activity in serum between two groups of patients (with and without ocular sarcoidosis). There is statistically significant difference in ACE activity in aqueous humor among patients with ocular and nonocular sarcoidosis. ACE activity in aqueous humor is significantly higher in patients with ocular sarcoidosis. CONCLUSION: Increased ACE activity in aqueous humor can point to a diagnosis of ocular sarcoidosis, without the need for ocular biopsy.

Increased Risk of Atherosclerosis in Patients with Sarcoidosis.

Sarcoidosis is a systemic granulomatous disease of unknown etiology. Recent studies demonstrated that its pathogenesis is related with enhanced oxidative stress (protein carbonylation and lipid peroxidation) and alterations in the circulating lipid profile. Alterations of lipid metabolism (including the reduction in high-density lipoprotein cholesterol levels and apolipoprotein A1 concentrations) induce plasma membrane, bronchial and lung capillary endothelial cell damage in sarcoidosis patients. Dyslipidemia is associated with increased oxidative stress, diminished overall antioxidative protection and increased risk for atherosclerosis. Very recently increased cardiovascular biomarkers (in particular alterations of lipoprotein A and d-dimer concentrations) were observed in sarcoidosis patients, mainly in those with a high risk of atherosclerosis. Chitotriosidase, a biomarker of sarcoidosis activity and macrophage activation, is increased in serum and bronchoalveolar lavage fluid of patients with sarcoidosis as well as in patients with atherosclerosis. Lipidomics and other recent methodologies allowed the discovery of proteins involved in lipid metabolism and sarcoidosis pathogenesis, such as serum amyloid A, a biomarker of sarcoidosis activity, involved in innate immune response, inflammation and apolipoprotein metabolism. In this review lipid metabolism alteration and atherosclerosis risk in sarcoidosis patients were discussed in order to contribute to this novel and interesting research topic.

GSTT1 and GSTM1 gene polymorphisims in sarcoidosis.

INTRODUCTION: Sarcoidosis is a granulomatous disease of unknown cause, which affects all systems, especially the lungs and the lymphatic system. Genetic and environmental factors are held accountable for the etiology. Based on the general opinion, sarcoidosis develops after exposure to a specific environmental agent by genetically susceptible individuals.  The present study aimed to evaluate the disease susceptibility of the GSTT1 and GSTM1 gene polymorphisms in the patients with sarcoidosis. METHOD: The present study included 78 patients; 38 patients with histopathologically verified sarcoidosis and 40 control subjects. Multiplex PCR method was used to determine the GSTT1 and GSTM1 gene polymorphisms. The genotype was determined based on the bands formed in the agarose gel electrophoresis. The statistical analysis was done using the chi-square test. RESULTS: The positive/negative genotype rates were 79%/21% and 53%/47%, respectively in the case group for the GSTT1 and GSTM1 gene polymorphisms, whereas the positive/negative genotype rates were 77%/23% and 55%/45% in the control group. There was no statistically significant difference in the positive and negative genotypes compared with the case group and the control group for the GSTT1 and GSTM1 gene polymorphisms (p > 0.05). DISCUSSION: The results from the present study suggest that there is not any association with the control group for the disease susceptibility of the GSTT1 and GSTM1 gene polymorphisms in patients with sarcoidosis, and this result should be supported by large-scale studies because of the limited number of cases in the present study.

Angiotensin converting enzyme I/D polymorphism and sarcoidosis risk.

BACKGROUND: This meta-analysis investigates the associations of angiotensin-converting enzyme (ACE) polymorphism and risk of sarcoidosis. MATERIAL AND METHOD: Two reviewers independently searched three databases including PubMed, EMBASE, and Cochrane database to identify published studies. Full texts of the selected studies were accessed and related data was extracted using a standardized data extraction form. RESULTS: A total of 18 studies contained a total of 1626 patients with sarcoidosis in case group and 2465 healthy controls in control group. Results of the current meta-analysis revealed that ACE DD genotype was associated with a significantly increased risk of sarcoidosis (OR=1.21; 95% CI, 1.06-1.38; I2=48%). In the race subgroup analysis, Asians with ACE DD genotype showed no significant increased risk of sarcoidosis (OR=1.37; 95% CI, 0.94-1.99; I2=78%). Caucasians with ACE DD genotype had an increased sarcoidosis risk (OR=1.16; 95% CI, 1.01-1.36; I2=24%). CONCLUSIONS: Our meta-analysis indicated that the ACE DD genotype correlated with an increased risk of sarcoidosis.

The serum angiotensin converting enzyme and lysozyme levels in patients with ocular involvement of autoimmune and infectious diseases.

BACKGROUND: Increased serum levels of angiotensin converting enzyme and lysozyme are considered as inflammatory markers for diagnosis of sarcoidosis which is an autoimmune inflammatory disease. The purpose of this study is to evaluate the significance of differences in serum angiotensin converting enzyme and lysozyme levels of patients with ocular involvement of other autoimmune inflammatory and infectious diseases. METHODS: This is a prospective study involving patients with ankylosing spondylitis, behcet's disease, presumed sarcoidosis, presumed latent tuberculosis, presumed latent syphilis, and control group. The serum levels of angiotensin converting enzyme and lysozyme were analyzed by enzyme-linked immunosorbent assay. Bonnferoni analysis was used to assess pairwise comparisons between the groups. RESULTS: There was a significant increase in serum angiotensin converting enzyme level in patients with presumed sarcoidosis compared to ankylosing spondylitis (p = 0.0001), behcet's disease (p = 0.0001), presumed latent tuberculosis (p = 0.0001), presumed latent syphilis (p = 0.0001), and control group (p = 0.0001). The increase in serum lysozyme level was significant for patients with presumed sarcoidosis with respect to ankylosing spondylitis (p = 0.0001), behcet's disease, (p = 0.0001) presumed latent tuberculosis (p = 0.001), presumed latent syphilis (p = 0.033), and control group (p = 0.0001). CONCLUSION: Elevated serum angiotensin converting enzyme levels are significant for patients with presumed sarcoidosis compared to ocular involvement of other autoimmune diseases such as behcet's disease and ankylosing spondylitis, and ocular involvement of infectious diseases such as presumed latent tuberculosis and presumed latent syphilis. However, elevated serum lysozyme level might be also detected in ocular involvement of infectious diseases such as presumed latent tuberculosis and presumed latent syphilis. TRIAL REGISTRATION NUMBER: NCT02627209. Date of registration: 12/09/2015.

Diagnostic Utility of Angiotensin-Converting Enzyme in Sarcoidosis: A Population-Based Study.

PURPOSE: Sarcoidosis is a disease with heterogenous clinical presentations. Diagnosis of sarcoidosis is often challenging with the lack of gold standard tests. In this study, we investigated the diagnostic utility of angiotensin-converting enzyme (ACE) for diagnosis of sarcoidosis. METHODS: A cohort of Olmsted County, Minnesota residents who were diagnosed with sarcoidosis between January 1, 1984 and December 31, 2013 was identified based on individual medical record review. ACE levels recorded in the medical records of all subjects at the time of diagnosis were extracted. Comparator subjects were residents of Olmsted County, Minnesota who had ACE levels tested the same time period but did not have a diagnosis of sarcoidosis. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the c-statistic of high versus low/normal ACE to diagnose sarcoidosis were calculated. RESULTS: A total of 3277 Olmsted County residents age ≥18 years had at least one ACE test in 1984-2013. The sarcoidosis incidence cohort contained 295 Olmsted County residents diagnosed with sarcoidosis in 1984-2013. Of these, ACE tests were obtained in 251. The sensitivity and specificity of high ACE for diagnosis of sarcoidosis were 41.4 % (95 % CI 35.3-47.8 %) and 89.9 % (95 % CI 88.8-91.0 %), respectively. The PPV and NPV in this population were 25.4 % (95 % CI 21.3-29.9 %) and 94.9 % (95 % CI 85.0-87.4 %). CONCLUSIONS: This study demonstrated a poor sensitivity and insufficient specificity of high ACE for diagnosis of sarcoidosis suggesting a limited role of ACE in clinical practice.

Common chitotriosidase duplication gene polymorphism and clinical outcome status in sarcoidosis.

BACKGROUND: Chitotriosidase has been found to be useful as a sarcoidosis biomarker. In patients with better outcome lower values were observed. Some subjects have 24-base pair duplication in the chitotriosidase gene (CHIT1) that results in the production of inactive enzyme. This might influence the outcome of sarcoidosis and account for described observations. OBJECTIVES: The aim of this study was to correlate common CHIT1 duplication polymorphism and clinical outcome status in sarcoidosis (COS). METHODS: This retrospective study comprised 180 patients with sarcoidosis. COS at 3, 5 and 10 years was determined and correlated with CHIT1 24-base pair duplication polymorphism. CHIT1 genotyping was done by the PCR method. RESULTS: There was no significant correlation between CHIT1 24-base pair duplication polymorphism and COS at 3, 5 or 10 years but a subgroup analysis showed higher frequency of patients with Loefgren's syndrome (50% vs. 17.1%) and better COS in CHIT1 24-base pair duplication homozygotes vs. all other subjects in major COS groups (no, minimal and persistent disease) at 3 years (p=0.025) and borderline significant at 5 years (p = 0.090). CONCLUSIONS: In this study no correlation between CHIT1 24-base pair duplication polymorphism and COS was shown, but possible protective role of homozygous condition for CHIT1 24-base pair duplication polymorphism is suggested.

Tartrate-resistant acid phosphatase 5a in sarcoidosis: further evidence for a novel macrophage biomarker in chronic inflammation.

BACKGROUND/PURPOSE: Tartrate-resistant acid phosphatase (TRACP) 5a is expressed strongly in inflammatory macrophages (MΦ). Serum TRACP5a is elevated in rheumatoid arthritis patients with extra-articular manifestations of rheumatoid nodules, in a percentage of patients with end-stage chronic kidney disease, and may be a risk marker for acute myocardial infarction. This proof-of-concept study was undertaken in patients with sarcoidosis to further substantiate our hypothesis that TRACP5a protein is a biomarker for macrophages in other chronic inflammatory diseases. METHODS: Immunohistochemical staining for TRACP5a and CD68 was performed in tissues of 19 patients with sarcoidosis. We also measured circulating TRACP5a protein and other inflammation biomarkers including interkeukin-6, angiotensin-converting enzyme, and C-reactive protein in 13 patients. Twenty healthy age-matched nonsmoking individuals were used as the reference group. RESULTS: All sarcoidosis tissues showed strong staining for TRACP5a and CD68 in the non-caseating granulomatous lesions and localized specifically to MΦ, multinucleate giant cells, and epithelioid MΦ. Serum TRACP5a protein was elevated significantly in active sarcoidosis patients compared with the control group, and levels fluctuated with disease activity in one patient studied longitudinally. CONCLUSION: TRACP5a protein is expressed abundantly in the granulomatous tissues and may be elevated in a significant proportion of sarcoidosis patients. These findings further support our hypothesis that serum TRACP5a is derived from systemic inflammatory MΦ and thereby may be a biomarker of inflammation for sarcoidosis and also reflect its disease activity.

Extreme elevation of serum angiotensin-converting enzyme (ACE) activity: always consider familial ACE hyperactivity.

Measurement of serum angiotensin-converting enzyme (ACE) activity can be helpful in the diagnosis and disease monitoring of sarcoidosis. Elevated serum ACE activity is found in 60-70% of sarcoidosis patients. Usually, the ACE activity is mildly increased (<3-fold the upper limit of the reference range) in sarcoidosis patients. Extremely elevated ACE activity is suggestive of the benign condition known as 'familial hyperactivity of ACE'. Familial hyperactivity of ACE is a relatively rare condition and can be confirmed by genetic testing. Considering a genetic cause of strongly elevated serum ACE activity is important to prevent possible overdiagnostics. Here, we highlight the factors that may complicate the interpretation of serum ACE activity measurements, and we present two cases that illustrate the importance of interdisciplinary consultation when extremely elevated serum ACE activity is measured.

Angiotensin-converting enzyme inhibitors in the treatment of sarcoidosis and association with ACE gene polymorphism: case series.

Angiotensin-converting enzyme (ACE) is used as a marker for sarcoid disease activity. We present an observational study of four African-American patients all of whom demonstrated improvement in their sarcoidosis after treatment with ACE inhibitors for hypertension.

Expression of cathepsin K and tartrate-resistant acid phosphatase is not confined to osteoclasts but is a general feature of multinucleated giant cells: systematic analysis.

OBJECTIVE: Cathepsin K and tartrate-resistant acid phosphatase (TRAP) are two proteins expressed in osteoclastic giant cells. Recently we showed that lesional multinucleated giant cells (MNGs) in pulmonary granulomatosis with polyangiitis expressed these proteins. We aimed to clarify whether the expression of these two proteins has any specificity or is a general feature of MNGs associated with multiple types of granulomatous inflammation. METHODS: In total, 7 Crohn's disease (CD), 5 GCA, 5 giant cell myocarditis (GCM), 11 sarcoidosis and 6 tuberculosis cases were examined for expression of cathepsin K and TRAP using immunohistochemistry (IHC). Protein expression was semi-quantitatively classified as none, weak, moderate or strong. In addition, tissue TRAP activity was examined using an enzymatic reaction. RESULTS: The expression of cathepsin K was robust in >95% of MNGs of all examined disease groups, whereas TRAP expression varied; CD, GCA and tuberculosis showed strong TRAP expression. TRAP expression in sarcoidosis and GCM was weaker (CD vs GCM, P = 0.04; CD vs sarcoidosis, P = 0.06). Compared with IHC, TRAP detection using an enzymatic colour reaction had limited sensitivity. CONCLUSION: Expression of TRAP and cathepsin K is a general feature of MNGs and their expression might be related to histopathological pattern.

Human chitotriosidase: a sensitive biomarker of sarcoidosis.

BACKGROUND: Sarcoidosis is a multisystem granulomatous disease of unknown etiology. No suitable biomarkers are available to evaluate the evolution of this disease, which still has an unpredictable clinical course. Some years ago our research group proposed chitotriosidase as a potential biomarker with prognostic value, that however needed to be validated. AIMS AND METHODS: The aims of this study were to evaluate the sensitivity and specificity of chitotriosidase in a population of 232 sarcoidosis patients under the observation of our Sarcoidosis Regional Referral Centre in Siena and to analyse enzyme concentrations in different disease phenotypes (as defined by the recently published COS classification) to define its prognostic value. RESULTS: Serum chitotriosidase concentrations were significantly higher in patients than in healthy controls (p<0.0001) and were directly correlated with ACE levels (r=0.25, p<0.0001). ROC curve analysis revealed 88.6 % sensitivity and 92.8 % specificity. Enzyme concentrations were significantly higher in stage 3 sarcoidosis than in stage 0 (p=0.02). The lowest concentrations of chitotriosidase were found in untreated patients in remission (COS-1), while the highest enzyme concentrations were found in symptomatic patients with persistent disease on steroids and with functional deterioration in the last year (COS-9). In COS-9 subgroup, chitotriosidase decreased significantly after the increasing of steroid dose or the introduction of a new immunosuppressant therapy (p<0.01). CONCLUSION: Chitotriosidase proved to be a biomarker with good sensitivity and specificity that is easily detected in serum. It can be proposed in clinical practice to identify progressive patients requiring close follow-up, to detect relapses and to evaluate the effects of therapy.

ACE gene I/D polymorphism and risk of sarcoidosis development in Turkish patients.

INTRODUCTION: Etiology of sarcoidosis is unknown but the prevalence of disease in different ethnic groups and identical twins, family characteristics indicate that genetic predisposition is a possible factor. The angiotensin-converting enzyme (ACE) has been implicated in the pahophysiology of sarcoidosis. The aim of this study is to investigate the influence of a polymorphism in I/D (Insertion/Deletion) of the ACE gene on the susceptibility to sarcoidosis. PATIENTS AND METHODS: Our study included 70 Turkish patients who had histopathological diagnosis of sarcoidosis and 69 healthy age and sex matched control subjects. Polymerase chain reaction was used for analysing an I/D polymorphism in the gene coding for ACE. Genotyping was done according to bands that were formed on the agarose gel electrophoresis. Chi-square test was used for statistical analysis and p< 0.05 was accepted as significance. RESULTS: Although the D allele was more frequent in the sarcoidosis patients group, the frequency of the D allele was 67% and 54% respectively in the sarcoidosis and the control group. No significant difference in allele frequencies of I/I, I/D, D/D polymorphisms was observed between the sarcoidosis and control group (p> 0.05). Similarly allele frequencies of I/I, I/D, D/D polymorphisms was not different between sarcoidosis patients with extrapulmonary involvement and sarcoidosis patients without extrapulmonary involvement (p> 0.05). CONCLUSION: Our findings have showed that contribution of ACE gene polymorphisms to susceptibility of disease development in Turkish sarcoidosis patients is not different from the healthy control subjects.