Are Heat Shock Proteins an Important Link between Type 2 Diabetes and Alzheimer Disease?

Type 2 diabetes (T2D) and Alzheimer's disease (AD) are growing in prevalence worldwide. The development of T2D increases the risk of AD disease, while AD patients can show glucose imbalance due to an increased insulin resistance. T2D and AD share similar pathological features and underlying mechanisms, including the deposition of amyloidogenic peptides in pancreatic islets (i.e., islet amyloid polypeptide; IAPP) and brain (ß-Amyloid; Aß). Both IAPP and Aß can undergo misfolding and aggregation and accumulate in the extracellular space of their respective tissues of origin. As a main response to protein misfolding, there is evidence of the role of heat shock proteins (HSPs) in moderating T2D and AD. HSPs play a pivotal role in cell homeostasis by providing cytoprotection during acute and chronic metabolic stresses. In T2D and AD, intracellular HSP (iHSP) levels are reduced, potentially due to the ability of the cell to export HSPs to the extracellular space (eHSP). The increase in eHSPs can contribute to oxidative damage and is associated with various pro-inflammatory pathways in T2D and AD. Here, we review the role of HSP in moderating T2D and AD, as well as propose that these chaperone proteins are an important link in the relationship between T2D and AD.

Idiopathic Hypertrophic Spinal Pachymeningitis.

Hypertrophic pachymeningitis (HP) is a rare presentation with duramater thickening and fibrosis which can result in cranial or spinal compressive disease. Most cases of spinal HP require surgical management. We present an uncommon case of idiopathic hypertrophic spinal pachymeningitis (IHSP) in a 40-year-old male who showed complete improvement to steroids without any further relapses. The patient presented with bilateral upper limb weakness with magnetic resonance imaging (MRI) spine showing diffuse dural thickening of the entire spine with cervical cord compression. He had an extensive workup for underlying etiology and worsening symptoms until he was diagnosed with IHSP. Later, he was started on high-dose steroids with good response and no relapse after 2 years. A descriptive analysis of IHSP cases since 2009 including ours showed that it usually occurs after 50s with female preponderance. Weakness and sensory loss are the most common complaints with 50% patients showing clinical signs of myelopathy like hyperreflexia, clonus, Babinski sign and sensory level. Cerebrospinal fluid (CSF) and inflammatory markers like erythrocytic sedimentation rate (ESR) and C-reactive protein (CRP) can be used to assess disease progression and prognosis. Surgical removal of HP followed by steroids is the best line of management while steroids alone can be tried in cases where clinical signs of myelopathy are absent.

Subacute exposure to residual oil fly ash (ROFA) increases eHSP70 content and extracellular-to-intracellular HSP70 ratio: a relation with oxidative stress markers.

The purpose of this study was to evaluate whether exposure to particles induces an imbalance in 70-kDa heat shock proteins (HSP70). Since intracellularly (iHSP70) it has anti-inflammatory roles whereas extracellularly (eHSP70) it has pro-inflammatory roles, we evaluate the effect of residual oil fly ash (ROFA) exposure on eHSP70-to-iHSP70 ratio (H index), a biomarker of inflammatory status that is related to oxidative stress in plasma and lymphoid tissue. Wistar rats that received ROFA suspension for three consecutive days (750 µg) showed an increase in plasma eHSP70 levels (mainly the 72-kDa inducible form). Also, ROFA promoted alterations on plasma oxidative stress (increased protein carbonyl groups and superoxide dismutase activity, and decrease sulfhydryl groups). There was an increase in H index of the plasma/thymus with no changes in circulating leukocyte level, iHSP70, or oxidative stress markers in lymphoid tissues. Our results support the hypothesis that eHSP70 content and H index represent inflammatory and oxidative biomarkers.

Acute exercise boosts cell proliferation and the heat shock response in lymphocytes: correlation with cytokine production and extracellular-to-intracellular HSP70 ratio.

Exercise stimulates immune responses, but the appropriate "doses" for such achievements are unsettled. Conversely, in metabolic tissues, exercise improves the heat shock (HS) response, a universal cytoprotective response to proteostasis challenges that are centred on the expression of the 70-kDa family of intracellular heat shock proteins (iHSP70), which are anti-inflammatory. Concurrently, exercise triggers the export of HSP70 towards the extracellular milieu (eHSP70), where they work as pro-inflammatory cytokines. As the HS response is severely compromised in chronic degenerative diseases of inflammatory nature, we wondered whether acute exercise bouts of different intensities could alter the HS response of lymphocytes from secondary lymphoid organs and whether this would be related to immunoinflammatory responses. Adult male Wistar rats swam for 20 min at low, moderate, high or strenuous intensities as per an overload in tail base. Controls remained at rest under the same conditions. Afterwards, mesenteric lymph node lymphocytes were assessed for the potency of the HS response (42 °C for 2 h), NF-κB binding activity, mitogen-stimulated proliferation and cytokine production. Exercise stimulated cell proliferation in an "inverted-U" fashion peaking at moderate load, which was paralleled by suppression of NF-κB activation and nuclear location, and followed by enhanced HS response in relation to non-exercised animals. Comparative levels of eHSP70 to iHSP70 (H-index) matched IL-2/IL-10 ratios. We conclude that exercise, in a workload-dependent way, stimulates immunoinflammatory performance of lymphocytes of tissues far from the circulation and this is associated with H-index of stress response, which is useful to assess training status and immunosurveillance balance.

Concomitant idiopathic hypertrophic spinal pachymeningitis and Guillain-Barré syndrome in a patient: coincidence or a triggering mechanism?

Idiopathic hypertrophic spinal pachymeningitis (IHSP), a rare diffuse inflammatory thickening of the dura mater, and Guillain-Barré syndrome (GBS) are known entities but they have never been reported as concomitant diagnoses. To their knowledge, the authors present the first reported case in the international literature with supportive evidence for both IHSP (based on MRI, intraoperative, and histological findings) and GBS (based on history, clinical examination, and electrophysiological findings). They review the literature on IHSP and the diagnostic criteria for GBS, with the view of identifying a possible causative connection.