Heat shock protein 70 and albuminuria in patients with type 2 diabetes: a matched case control study

The role of heat shock proteins (HSPs) in type 2 diabetes mellitus pathophysiology

Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by sustained hyperglycemia caused by impaired insulin signaling and secretion. Metabolic stress, caused by an inappropriate diet, is one of the major hallmarks provoking inflammation, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction. Heat shock proteins (HSPs) are a group of highly conserved proteins that have a crucial role in chaperoning damaged and misfolded proteins to avoid disruption of cellular homeostasis under stress conditions. To do this, HSPs interact with diverse intra-and extracellular pathways among which are the insulin signaling, insulin secretion, and apoptosis pathways. Therefore, HSP dysfunction, e.g. HSP70, may lead to disruption of the pathways responsible for insulin secretion and uptake. Consistently, the altered expression of other HSPs and genetic polymorphisms in HSP-producing genes in diabetic subjects has made HSPs hot research in T2DM. This paper provides a comprehensive overview of the role of different HSPs in T2DM pathogenesis, affected cellular pathways, and the potential therapeutic strategies targeting HSPs in T2DM.

Association of elevated extracellular HSP72 in albuminuria with systemic inflammation and disease progression in type 2 diabetic kidney disease

BACKGROUND

Sub-clinical inflammation in hyperglycemia is tied to the pathogenesis of diabetic kidney disease (DKD). Though well known for its immunostimulatory function, the significance of extracellular heat shock protein 72 (eHSP72) in DKD is not well studied. We aimed to determine the association of extracellular HSP72 with systemic inflammation and the progression of DKD, and explore its possible clinical significance in DKD.

METHODS

160 type 2 diabetic individuals were enrolled in the study. Their anthropometric data, routine biochemical parameters, urinary renal function parameters, and blood count parameters were estimated. Plasma from patients' blood samples were used to estimate HSP72 and interleukin 1β (IL-1β) using sandwich immunoassays.

RESULTS

Plasma eHSP72 is elevated in DKD. Pairwise comparisons showed the drastic elevation of eHSP72 in the presence of albuminuria. A significant positive relationship was observed between plasma levels of eHSP72 and IL-1β. eHSP72 levels did not statistically differ between micro and macro-albuminuric DKD. However, it was inversely associated with estimated glomerular filtration rate, the index of disease severity, independent of age, gender, diabetes duration and absolute monocyte count. At a cutoff of 0.52 ng/ml, with sensitivity of 64.1 % and specificity of 69.2 %, plasma eHSP72 differentiated the presence of DKD in type 2 diabetics with statistical significance.

CONCLUSION

The positive relationship of eHSP72 and IL-1β with worsening DKD likely indicates their participation in immunostimulatory pathways of renal fibrosis. eHSP72 may be closely linked to albuminuria-induced tubular injury and likely contributes to fibrotic changes in the progression of DKD. From our study, we infer the possible clinical significance of eHSP72 as a marker of sub-clinical renal damage in DKD, and the implication of IL-1β-associated mechanisms in DKD progression.

Serum Level of Heat Shock Protein 70 in Patients with Type 2 Diabetes Mellitus in Basrah, Iraq

Diabetes mellitus is a chronic metabolic disease with an increasing prevalence, caused by a defect in insulin production, insulin action, or both, and can increase the risk for the development of microvascular as well as macrovascular complications. Heat shock protein70 is considered a family of a larger group of proteins known as heat shock proteins, which their expression is induced when the cells are subjected to environmental stress. They are believed to keep the native folding of proteins in cells under stressful conditions and their therapeutic role. Therefore, this study aimed to investigate the serum level of HSP70 in patients with type 2 diabetes mellitus (T2DM) to assess if there is an association of HSP70 with T2DM and to evaluate the effect of age and duration of disease on the serum level of HSP70. Ninety-one patients with T2DM were recruited, and 85 individuals with the same age range and sex as healthy controls. Serum HSP70, fasting blood sugar, and HbA1c were measured. The results revealed that the level of HSP70 was significantly higher in the diabetic group compared to the control group (P value<0.05). The level of HSP70 showed a significant positive correlation with age and duration of disease as well as with fasting blood sugar and HbA1c. The study suggested that HSP70 may have the potential to be used as an indicator of metabolic derangement and a prognostic biomarker in diabetes.

Increased eHSP70-to-iHSP70 ratio in prediabetic and diabetic postmenopausal women: a biomarker of cardiometabolic risk

Decreased estrogen levels in menopause are associated with anthropometric, metabolic, and inflammatory impairments, predisposing women to cardiometabolic risk factors such as diabetes. Menopause and type two diabetes (DM2) are marked by altered heat shock response (HSR), shown by decreased expression of the 70-kDa heat shock protein in the intracellular milieu (iHSP70). While iHSP70 plays an anti-inflammatory role, extracellular HSP70 (eHSP70) may mediate pro-inflammatory pathways and has been associated with insulin resistance in DM2. Considering the roles of these proteins according to localization, the eHSP70-to-iHSP70 ratio (H-index) has been proposed as a biomarker for HSR. We, therefore, evaluated whether this biomarker is associated with glycemic and inflammatory status in postmenopausal women. In this transversal study, 36 postmenopausal women were grouped according to fasting glycemia status as either the control group (normoglycemic, ≤ 99 mg/dL) or DM2 (prediabetic and diabetic, glycemia ≥ 100 mg/dL). DM2 group showed higher triglyceride/glucose (TyG) index and plasma atherogenic index (PAI), both of which are indicators of cardiometabolic risk. In addition, we found that the eHSP70-to-iHSP70 ratio (plasma/peripheral blood mononuclear cells-PBMC ratio) was higher in the DM2 group, compared with the control group. Furthermore, blood leukocyte and glycemia levels were positively correlated with the eHSP70-to-iHSP70 ratio in women that presented H-index values above 1.0 (a.u.). Taken together, our results highlight the eHSP70-to-iHSP70 ratio as a biomarker of altered HSR in DM2 postmenopausal women.

Effects of Pentoxifylline on Serum Markers of Diabetic Nephropathy in Type 2 Diabetes

OBJECTIVE

To investigate the effects of pentoxifylline (PTX) in combination with losartan compared to the high dose of losartan alone on serum markers of diabetic nephropathy such as HSP70, copeptin, CRP, and TNFα in patients with type 2 diabetes and nephropathy.

METHODS

A single-center, randomized, double-blind, open-label clinical trial was conducted. Sixty-two patients were eligible and allocated to "PTX + losartan" and "high-dose losartan" arms of the trial using software for random number generation. The first arm received 400 mg PTX two times a day (BD) plus 50 mg losartan daily, while the second arm received 50 mg losartan two times a day (BD) for 12 weeks. Comparison of the biomarkers' levels before and after treatment was done using paired sample t test variance. ANCOVA was applied to evaluate the comparative efficacy of the two interventions. The effect size was calculated and reported for each biomarker.

RESULTS

Urine albumin excretion (UAE), hs-CRP, and HbA1c significantly decreased in both trial arms compared to the baseline measures. Copeptin and TNFα showed significant differences (after vs before) only in the losartan group (p = 0.017 and p = 0.043, respectively). The losartan arm was more successful in reducing TNFα, copeptin, HSP70, systolic blood pressure (SBP), and diastolic blood pressure (DBP) values (p = 0.045, effect size = 7.3%; p = 0.018, effect size 10.1%; p = 0.046, effect size 4.7%, p = 0.001, effect size 23%; p = 0.012, effect size 10.2%, respectively) and the PTX arm was associated with a superior reduction of UAE and hs-CRP levels (p = 0.018, effect size 9.1%; p = 0.028, effect size 9.2%, respectively).

CONCLUSION

Add-on PTX to losartan may have more effective anti-inflammatory and anti-albuminuric roles and therefore may be more applicable in the management of diabetic nephropathy compared with high-dose losartan alone.

TRAIL REGISTRATION

Trial number IRCT 20121104011356N10.

The abnormal level of HSP70 is related to Treg/Th17 imbalance in PCOS patients

BACKGROUND

Polycystic ovary syndrome (PCOS) is a disease with chronic nonspecific low-grade inflammation. The imbalance of immune cells exists in PCOS. Several studies have found that heat shock protein 70 (HSP70) may be involved in the immunological pathogenesis of PCOS, but the relationship between HSP70 and Regulatory T cell (Treg)/T helper cell 17(Th17) ratio remains unclear. This study aims to explore the correlation between HSP70 and Treg/Th17 ratio and to provide evidence for the role of HSP70 in the immunological etiology of PCOS.

RESULTS

There was no significant difference in age and body mass index (BMI) between the two groups. The concentrations of basal estradiol (E₂), basal follicle-stimulating hormone (FSH) did not show a significant difference between the two groups. The concentrations of basal luteinizing hormone (LH) (P < 0.01), testosterone (T) (P < 0.01), glucose (P < 0.001) and insulin (P < 0.001) in PCOS patients were significantly higher than those in the control group. The protein levels of HSP70 were significantly higher in serum in the PCOS group (P < 0.001). The percentage of Treg cells was significantly lower (P < 0.01), while the percentage of the Th17 cells of the PCOS group was significantly higher than that of the control group (P < 0.05). The ratio of Treg/Th17 in the PCOS group was significantly lower (P < 0.001). The concentrations of Interleukin (IL)-6, IL-17, and IL-23 were significantly higher, while the levels of IL-10 and Transforming growth factor-β (TGF-β) were significantly lower in the PCOS group (P < 0.001). Spearman rank correlation analysis showed a strong negative correlation of serum HSP70 levels with Treg/Th17 ratio, IL-10, and TGF-β levels. In contrast, HSP70 levels were significantly positively correlated with IL-6, IL-17, IL-23, LH, insulin, and glucose levels.

CONCLUSION

The abnormal level of HSP70 is correlated with Treg/Th17 imbalance and corresponding cytokines, which indicates that HSP70 may play an important role in PCOS immunologic pathogenesis.

Changes in the Proteome Profile of People Achieving Remission of Type 2 Diabetes after Bariatric Surgery

Bariatric surgery (BS) results in metabolic pathway recalibration. We have identified potential biomarkers in plasma of people achieving type 2 diabetes mellitus (T2DM) remission after BS. Longitudinal analysis was performed on plasma from 10 individuals following Roux-en-Y gastric bypass (n = 7) or sleeve gastrectomy (n = 3). Sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS) was done on samples taken at 4 months before (baseline) and 6 and 12 months after BS. Four hundred sixty-seven proteins were quantified by SWATH-MS. Principal component analysis resolved samples from distinct time points after selection of key discriminatory proteins: 25 proteins were differentially expressed between baseline and 6 months post-surgery; 39 proteins between baseline and 12 months. Eight proteins (SHBG, TF, PRG4, APOA4, LRG1, HSPA4, EPHX2 and PGLYRP) were significantly different to baseline at both 6 and 12 months post-surgery. The panel of proteins identified as consistently different included peptides related to insulin sensitivity (SHBG increase), systemic inflammation (TF and HSPA4-both decreased) and lipid metabolism (APOA4 decreased). We found significant changes in the proteome for eight proteins at 6- and 12-months post-BS, and several of these are key components in metabolic and inflammatory pathways. These may represent potential biomarkers of remission of T2DM.

The Role of Heat Shock Proteins in Type 1 Diabetes

Type 1 diabetes (T1D) is a T-cell mediated autoimmune disease characterized by recognition of pancreatic β-cell proteins as self-antigens, called autoantigens (AAgs), followed by loss of pancreatic β-cells. (Pre-)proinsulin ([P]PI), glutamic acid decarboxylase (GAD), tyrosine phosphatase IA-2, and the zinc transporter ZnT8 are key molecules in T1D pathogenesis and are recognized by autoantibodies detected in routine clinical laboratory assays. However, generation of new autoantigens (neoantigens) from β-cells has also been reported, against which the autoreactive T cells show activity. Heat shock proteins (HSPs) were originally described as “cellular stress responders” for their role as chaperones that regulate the conformation and function of a large number of cellular proteins to protect the body from stress. HSPs participate in key cellular functions under both physiological and stressful conditions, including suppression of protein aggregation, assisting folding and stability of nascent and damaged proteins, translocation of proteins into cellular compartments and targeting irreversibly damaged proteins for degradation. Low HSP expression impacts many pathological conditions associated with diabetes and could play a role in diabetic complications. HSPs have beneficial effects in preventing insulin resistance and hyperglycemia in type 2 diabetes (T2D). HSPs are, however, additionally involved in antigen presentation, presenting immunogenic peptides to class I and class II major histocompatibility molecules; thus, an opportunity exists for HSPs to be employed as modulators of immunologic responses in T1D and other autoimmune disorders. In this review, we discuss the multifaceted roles of HSPs in the pathogenesis of T1D and in autoantigen-specific immune protection against T1D development.

Association Of Nocturnal Intermittent Hypoxia With Heat Shock Protein 70 In Patients With Obstructive Sleep Apnea: A Pilot Study

Introduction — Nocturnal intermittent hypoxia in obstructive sleep apnea (OSA) causes cellular stress and consequent change in inducible heat shock protein 70 (HSP70) level. Thus, the objective of this study was to determine the relationship among nocturnal hypoxia and the serum HSP70 level in patients with severe OSA. Material and Methods — The study involved 34 patients with a clinical diagnosis of moderate to severe OSA (24 men and 10 women). Patients without OSA (10 men and 5 women) were included as a control group. The groups were similar in age. The polysomnographic monitoring was carried by standart methodology. Blood sampling for determining the HSP70 level was carried out between 8:00 and 9:00 am after polysomnographic monitoring. Results — The results of this study demonstrated a high apnea/hypopnea index (AHI), which determined the OSA severity and decreased the blood oxygen saturation (SaO2) (p<0.05). Sleep fragmentation in OSA patients confirmed an increase in respiratory arousal index (ArI). The HSP70 level significantly increased in OSA patients compared with the control group. Correlation analysis showed a positive relationship between HSP70 and AHI (R=0.5) in patients with OSAS, as well as a negative relationship between HSP70 and SaO2 (R=-0.3). Conclusion — Our results demonstrated a high level of HSP70 in patients with severe OSA syndrome vs. those without it. In OSA patients, a direct correlation was found between the HSP70 level and AHI, as well as an inverse correlation between the AHI level and SaO2. These findings suggested an association between the level of inducible HSP70 and nocturnal hypoxia in OSA patients.

Vitamins Modulate the Expression of Antioxidant Genes in Progesterone-Treated Pancreatic β Cells: Perspectives for Gestational Diabetes Management

Gestational diabetes (GD) is a condition defined as carbohydrate intolerance and hyperglycemia beginning in the second trimester of pregnancy, which overlaps with the progesterone exponential increase. Progesterone has been shown to cause pancreatic β-cell death by a mechanism dependent on the generation of reactive oxygen species and oxidative stress. Herein, we studied the effect of this hormone on the expression of 84 genes related to oxidative stress and oxidant defense in pancreatic RINm5F cell lineage. Cells were incubated with 0.1, 1.0, or 100 μM progesterone for 6 or 24 h, in the presence or absence of the vitamins E and C. Among the investigated genes, five of them had their expression increased, at least 2-fold, in two different concentrations independently of the time of incubation, or at the same concentration at the different time points, including those that encode for stearoyl-CoA desaturase 1 (Scd1), dual oxidase 1 (Duox1), glutathione peroxidase 6 (GPx6), heme oxygenase 1 (Hmox1), and heat shock protein a1a (Hspa1a). Vitamins E and C were able to increase, in progesterone-treated cells, the expression of genes with antioxidant function such as Hmox1, but decreased Scd1 expression, a gene with prooxidant function. At cytoplasmic level, progesterone positively modulated Hmox1 and Hspa1a content. These results suggest that the protein encoded by these genes might protect cells against progesterone induced-oxidative damage, opening perspectives to elucidate the molecular mechanism involved in progesterone action in GD, as well as for the development of antioxidant strategies for the prevention and treatment of this disease.

Is the placental proteome impaired in well-controlled gestational diabetes?

In pregnancy complicated by gestational diabetes mellitus (GDM), the human placenta shows several pathological functional and structural changes, but the extent to which maternal glycemic control contributes to placental abnormalities remains unclear. The aim of this study was to profile and compare the proteome of placentas from healthy pregnant women and those with GDM, to investigate the placenta-specific protein composition and possible changes of its function in presence of GDM. Quantitative proteomic analysis, based on LC-MS^E approach, revealed that higher (approximately 15% increase) levels of galectin 1 and collagen alpha-1 XIV chain (although the difference regarding the latter was at the limit of significance) were present in GDM samples, while heat shock 70 kDa protein 1A/1B was less abundant in GDM placental tissue. These data seem to indicate that GDM, when well controlled, did not markedly affect the placental proteome.

The influence of high-fat, high-sugar diet and bariatric surgery on HSP70 and HSP90 plasma and liver concentrations in diet-induced obese rats

Metabolic surgery ameliorates insulin resistance and is associated with long-term, effective weight loss, but the mechanisms involved remain unknown. Here, the duodenal-jejunal omega switch (DJOS) surgery in combination with high-fat, high-carbohydrate diet was performed on diet obese rats and joint effects of bariatric surgery and different dietary patterns on heat shock protein 70 (HSP70) and HSP90 plasma and liver concentrations were measured. We found that plasma and liver levels of HSP70 were lower after DJOS surgery in comparison to the control in the groups of animals kept on control diet (CD) and high-fat, high-sugar diet (HFS) but the postoperative change of the diet led to the increase in HSP70 in plasma and liver concentration in DJOS-operated animals. A high-calorie meal, rich in carbohydrates and fats, significantly increased circulating levels of HSP90, reducing the normalising effect of DJOS. The HFS diet applied during all stages of the experiment led to the higher levels of liver HSP90 concentration. The combination of CD and DJOS surgery was the most efficient in the lowering of the HSP90 liver concentration. The normalisation of circulating levels and liver concentrations of HSP70 and HSP90 may be achieved in a combination of DJOS procedure with a proper dietary plan.

Extracellular cell stress (heat shock) proteins-immune responses and disease: an overview

Extracellular cell stress proteins are highly conserved phylogenetically and have been shown to act as powerful signalling agonists and receptors for selected ligands in several different settings. They also act as immunostimulatory 'danger signals' for the innate and adaptive immune systems. Other studies have shown that cell stress proteins and the induction of immune reactivity to self-cell stress proteins can attenuate disease processes. Some proteins (e.g. Hsp60, Hsp70, gp96) exhibit both inflammatory and anti-inflammatory properties, depending on the context in which they encounter responding immune cells. The burgeoning literature reporting the presence of stress proteins in a range of biological fluids in healthy individuals/non-diseased settings, the association of extracellular stress protein levels with a plethora of clinical and pathological conditions and the selective expression of a membrane form of Hsp70 on cancer cells now supports the concept that extracellular cell stress proteins are involved in maintaining/regulating organismal homeostasis and in disease processes and phenotype. Cell stress proteins, therefore, form a biologically complex extracellular cell stress protein network having diverse biological, homeostatic and immunomodulatory properties, the understanding of which offers exciting opportunities for delivering novel approaches to predict, identify, diagnose, manage and treat disease.This article is part of the theme issue 'Heat shock proteins as modulators and therapeutic targets of chronic disease: an integrated perspective'.

Heat Shock Proteins in Vascular Diabetic Complications: Review and Future Perspective

Heat shock proteins (HSPs) are a large family of proteins highly conserved throughout evolution because of their unique cytoprotective properties. Besides assisting protein refolding and regulating proteostasis under stressful conditions, HSPs also play an important role in protecting cells from oxidative stress, inflammation, and apoptosis. Therefore, HSPs are crucial in counteracting the deleterious effects of hyperglycemia in target organs of diabetes vascular complications. Changes in HSP expression have been demonstrated in diabetic complications and functionally related to hyperglycemia-induced cell injury. Moreover, associations between diabetic complications and altered circulating levels of both HSPs and anti-HSPs have been shown in clinical studies. HSPs thus represent an exciting therapeutic opportunity and might also be valuable as clinical biomarkers. However, this field of research is still in its infancy and further studies in both experimental diabetes and humans are required to gain a full understanding of HSP relevance. In this review, we summarize current knowledge and discuss future perspective.

Heat shock protein-70 and hypoxia inducible factor-1α in type 2 diabetes mellitus patients complicated with retinopathy

PURPOSE

To elucidate the role of heat shock protein-70 (HSP70) and hypoxia inducible factor-1α (HIF-1α) in diabetic retinopathy (DR) patients.

DESIGN AND METHODS

A comparative study was done on the serum level of both HSP70 and HIF-1α in 50 patients with type 2 diabetes mellitus (T2DM) without DR, 50 patients with T2DM and DR and 70 healthy control subjects.

RESULTS

HSP70 and HIF-1α were significantly increased in T2DM patients compared to controls and increased in patients with T2DM & DR compared to T2DM patients without DR (p < 0.0001). HSP70 did not differ among the patients with different stages of DR, while HIF-1α increased significantly in grades 3 and 4 DR patients compared to grades 1 and 2 DR patients. A strong correlation was found between HIF-1α and the development of DR (r = 0.835, p = 0.00) but not with HSP70. HIF-1α can be used as a predictor for development of DR but not HSP70.

CONCLUSIONS

Our study was the first that investigated both HSP70 and HIF-1α in humans and was the first that measured their levels in serum of patients with DR. The study suggested that HSP70 might have a protective function in T2DM patients rather than a therapeutic function. HIF-1α had an upper hand in the development and progression of DR. Induction of HSP70 and blockage of HIF-1α could lead to the development of novel prophylactic and therapeutic strategies for DR and potentially other diabetic complications.

Toll-like receptor 2 and type 2 diabetes

Innate immunity plays a crucial role in the pathogenesis of type 2 diabetes and related complications. Since the toll-like receptors (TLRs) are central to innate immunity, it appears that they are important participants in the development and pathogenesis of the disease. Previous investigations demonstrated that TLR2 homodimers and TLR2 heterodimers with TLR1 or TLR6 activate innate immunity upon recognition of damage-associated molecular patterns (DAMPs). Several DAMPs are released during type 2 diabetes, so it may be hypothesized that TLR2 is significantly involved in its progression. Here, we review recent data on the important roles and status of TLR2 in type 2 diabetes and related complications.

The lost correlation between heat shock protein 70 (HSPA1A) and plasminogen activator inhibitor-1 in patients with type 2 diabetes and albuminuria

We aimed to study the relation between plasma levels of stress-induced heat shock protein 70 (HSPA1A) with plasminogen activator inhibitor-1 (PAI-1) and high-density lipoprotein cholesterol (HDL-C), apolipoprotein A1 (Apo-A1), and HDL-C/Apo-A1 ratio. In a matched case-control study on patients with diabetes (40 patients with albuminuria and 40 without albuminuria matched for age, sex, and body mass index), we observed that plasma levels of HSPA1A and PAI-1 are increased in patients with albuminuria (0.55 ± 0.02 vs. 0.77 ± 0.04 ng/ml, p value <0.001 for HSPA1A; 25.9 ± 2 vs. 31.8 ± 2.4 ng/ml, p value <0.05 for PAI-1). There was a significant correlation between HSPA1A and PAI-1 in diabetic patients without albuminuria (r = 0.28; p value = 0.04), but not in those with albuminuria (r = 0.07; p value = 0.63). No association was found between HSPA1A and HDL-C, between HSPA1A and Apo-A1, or between HSPA1A and HDL-C/Apo-A1 ratio. We concluded that there is a direct correlation between plasma HSPA1A and PAI-1 levels in patients with diabetes, which is lost when they develop albuminuria.

The detection and role of heat shock protein 70 in various nondisease conditions and disease conditions: a literature review

As an intracellular polypeptide, heat shock protein 70 (HSP70) can be exposed on the plasma membrane and/or released into the circulation. However, the role of HSP70 in various nondisease and disease conditions remains unknown. Quantitative methods for the detection of HSP70 have been used in clinical studies, revealing that an increase in circulating HSP70 is associated with various types of exercise, elderly patients presenting with inflammation, mobile phones, inflammation, sepsis, chronic obstructive pulmonary disease, asthma, carotid intima-media thickness, glutamine-treated ill patients, mortality, diabetes mellitus, active chronic glomerulonephritis, and cancers. Circulating HSP70 decreases with age in humans and in obstructive sleep apnea, arteriosclerosis, atrial fibrillation (AF) following coronary artery bypass surgery, nonalcoholic fatty liver disease, moderate-to-severe alcoholic fatty liver disease, hepatic steatosis, and Helicobacter pylori infection. In conclusion, quantitative methods can be used to detect HSP70, particularly in determining circulating HSP70 levels, using more convenient and rapid screening methods. Studies have shown that changes in HSP70 are associated with various nondisease and disease conditions; thus, HSP70 might be a novel potential biomarker reflecting various nondisease conditions and also the severity of disease conditions. However, the reliability and accuracy, as well as the underlying mechanism, of this relationship remain poorly understood, and large-sample clinical research must be performed to verify the role.

Increased circulating heat shock protein 70 (HSPA1A) levels in gestational diabetes mellitus: a pilot study

Recent data indicate that serum Hsp70 (HSPA1A) levels are increased in type 1 and 2 diabetes mellitus. However, there is no report in the literature on circulating Hsp70 levels in gestational diabetes mellitus. In this pilot study, we measured serum Hsp70 levels in 11 pregnant women with pregestational diabetes, 38 women with gestational diabetes, and 40 healthy pregnant women with ELISA. Plasma glucose levels, serum insulin concentrations, HbA1c values, and the Homeostatic Model Assessment-Insulin Resistance (HOMA-IR) index were also determined. According to our results, serum Hsp70 concentrations were significantly higher in women with pregestational and gestational diabetes mellitus than in healthy pregnant women. In addition, pregestational diabetic women had significantly higher Hsp70 levels than those with gestational diabetes. Furthermore, in the group of women with gestational diabetes mellitus, serum Hsp70 levels showed a significant positive correlation with HbA1c values. However, there was no other relationship between clinical features and metabolic parameters of the study subjects and their serum Hsp70 levels in either study group. In conclusion, we demonstrated for the first time in the literature that serum Hsp70 levels are increased and correlate with HbA1c values in women with gestational diabetes mellitus. Nevertheless, further studies are needed to determine whether circulating Hsp70 plays a causative role in the pathogenesis of gestational diabetes or elevated serum Hsp70 levels are only consequences of the disease.

COPD and levels of Hsp70 (HSPA1A) and Hsp27 (HSPB1) in plasma and lymphocytes among coal workers: a case-control study

This case-control study aimed to investigate whether the levels of Hsp70 (HSPA1A) and Hsp27 (HSPB1) in plasma and lymphocytes were associated with the risk of chronic obstructive pulmonary disease (COPD) among coal workers. A total of 76 COPD cases and 48 age-matched healthy controls from a group of coal workers were included. The case group consisted of 35 COPD patients whose condition was complicated with coal workers' pneumoconiosis (CWP) and 41 COPD patients without CWP. Heat shock proteins (Hsps) in plasma and lymphocytes were detected by ELISA and flow cytometry, respectively. Multiple logistic regression models were applied to estimate the association between Hsp levels and COPD risk. Our results showed that plasma Hsp70 and lymphocyte Hsp27 levels were significantly higher and plasma Hsp27 levels were significantly lower in COPD cases than in controls (p < 0.01). No significant differences in lymphocyte Hsp70 levels were found between COPD cases and the matched subjects. Higher plasma Hsp70 levels (odds ratio (OR) = 13.8, 95 % confidence interval (CI) = 5.7-33.5) and lower plasma Hsp27 levels (OR = 4.6, 95 % CI = 2.0-10.5) were significantly associated with an increased risk of COPD after adjusting for confounders. Higher lymphocyte Hsp27 levels were only associated with an increased risk of COPD with CWP (OR = 6.6, 95 % CI = 2.0-22.1) but not with an increased risk of COPD without CWP (OR = 3.0, 95 % CI = 0.9-8.9). Additionally, there were strong joint effects of different Hsps on COPD risk. These results showed that higher levels of plasma Hsp70 and lower levels of plasma Hsp27 might be associated with an increased risk of COPD among coal workers. They may have the potential to serve as monitoring markers for COPD in coal workers.

Analysis of serum heat shock protein 70 (HSPA1A) concentrations for diagnosis and disease activity monitoring in patients with rheumatoid arthritis

Heat shock proteins (HSPs) have been repeatedly implicated in the pathogenesis of rheumatoid arthritis (RA). The authors aimed to study applicability of heat shock protein 70 (HSPA1A) serum levels as a diagnostic factor and a severity indicator in patients with RA and to quantify cut-off point that predicts status of RA with highest specificity. A total of 76 patients with RA and 36 healthy adults were studied in this case-control analysis. Patients had a higher HSPA1A level than the control group (0.78 ± 0.13 vs. 0.12 ± 0.02 ng/mL, p = 0.006), irrespective of presence of absence of rheumatoid factor or anti-citrullinated cyclic peptide. Next, diagnostic accuracy of the HSPA1A in diagnosis of RA was evaluated (area under curve 0.71; p < 0.05). HSPA1A predicted status of having RA in levels above 0.42 ng/mL with more than 90 % specificity. In addition to diagnostic value, HSPA1A can distinguish between high disease activity (1.66 ± 0.75 ng/mL) and low (0.49 ± 0.1 ng/mL), moderate (0.52 ± 0.12 ng/mL), or remission phase (0.48 ± 0.11 ng/mL). Moreover, patients in remission still had a higher HSPA1A level compared to normal subject (0.48 ± 0.11 vs. 0.12 ± 0.02 ng/mL, p < 0.05). Our results showed that serum HSPA1A could be implemented as a specific tool to facilitate diagnosis and monitoring disease activity in patients with rheumatoid arthritis.