A nicotina é o principal componente do tabaco e dos cigarros eletrônicos. A exposição crônica a nicotina, em quantidades semelhantes às atingidas pelo tabagismo humano, é responsável por piora da lesão renal aguda e da doença renal crônica. O gene klotho, predominantemente expresso no rim, foi descoberto após uma mutação insercional, com o surgimento de um fenótipo semelhante ao envelhecimento humano nos camundongos homozigotos para esse transgene. A proteína Klotho transmembrana tem ação de co-receptor do fator de crescimento fibroblástico 23 (FGF-23) e sua forma secretada atua em diversas vias intracelulares e em órgãos a distância. A deficiência de Klotho ocorre no envelhecimento, em situações que levam a lesão renal aguda e na doença renal crônica. A expressão reduzida de Klotho também agrava lesão renal aguda e participa da progressão da doença renal crônica, enquanto o seu aumento, ou a sua reposição, protegem dos processos inflamatórios e do estresse oxidativo. Neste estudo, objetivamos avaliar os efeitos renais, hemodinâmicos e sobre a expressão de Klotho da exposição crônica a nicotina e quais os efeitos dessa exposição nos animais haploinsuficientes para o transgene klotho (Kl+/-). Utilizamos para estas avaliações camundongos Kl+/- e seus controles wild type (Kl+/+), que foram expostos a nicotina (200 mcg/mL) ou veículo (sacarina 2%) diluídos em água por 28 dias. Ao final do estudo foram avaliados diurese, eletrólitos plasmáticos e urinários, ureia, aldosterona, ADH, FGF-23 e PTH intactos plasmáticos, expressão protéica renal de Klotho, alfa7-nAchR, NHE3, ENaC, NKCC2, AQP2, e-NOS, VEGF, MnSOD e renina, expressão genica renal de klotho, interleucinas, TBARS e GSH em tecido renal, taxa de filtração glomerular por FITC-inulina, pressão arterial e frequência cardíaca invasivas, sensibilidade baroreflexa e modulação autonômica cardíaca e periférica por análise espectral. Após a exposição a nicotina, os animais Kl+/+ apresentaram redução da expressão renal da proteína e do RNAm de Klotho e uma tendência a aumento dos níveis plasmáticos de FGF-23, associados a uma queda da diurese e da taxa de filtração glomerular, sem alteração dos níveis de ADH. Esses animais Kl+/+ também apresentaram aumento da sensibilidade barorreflexa em resposta ao nitroprussiato e um predomínio da modulação simpática cardíaca, com redução da expressão renal dos alfa7-nAchR. Os animais Kl+/- tiveram níveis renais ainda menores de Klotho após a exposição a nicotina, com aumento de TBARS, IL-6, uréia e aldosterona em relação aos Kl+/- não expostos. A diurese, a taxa de filtração glomerular e a expressão dos alfa7-nAchR não se reduziram e não houve aumento da sensibilidade barorreflexa após exposição a nicotina, com um predomínio da modulação parassimpática cardíaca, nesses animais Kl+/-. A ingesta hídrica, a pressão arterial e a frequência cardíaca foram semelhantes entre os 4 grupos. A proteinúria foi maior nos animais Kl+/- do que nos animais Kl+/+ após a exposição a nicotina. Podemos concluir que a exposição crônica à nicotina reduz a expressão renal de Klotho, estimula vias de inflamação, fibrose e estresse oxidativo renais e tem efeitos renais e sistêmicos diferentes de acordo com os níveis basais de Klotho / Nicotine is a major compound of tobacco and electronic cigarettes. Chronic exposure to nicotine concentrations that are similar to human smoke worsens acute kidney injury and chronic kidney disease. The klotho (Kl) gene is expressed predominantly by the kidney and was discovered after an unintentional insertional mutation that resulted, in transgenic homozygous mice, in a phenotype similar to human aging. Klotho transmembrane protein acts as a co-receptor to fibroblastic growth factor 23 (FGF-23) and the secreted form interacts in multiple intracellular pathways, with effects in distant organs. Klotho deficiency occurs in aging and in multiple acute kidney injury and chronic kidney disease etiologies, whereas klotho upregulation and replacement protect from inflammation and oxidative stress. Here, we investigated renal and hemodynamic effects of chronic nicotine exposure, its effects over renal expression of Kl, and compared wild type (Kl+/+) and Kl haploinsufficient mice (Kl+/-) in terms of the effects of that exposure. Kl+/- and Kl+/+ mice received nicotine (200 ?g/ml) or vehicle (saccharine 2%) in drinking water for 28 days. We evaluated diuresis, ions in serum and urine, urea, plasma and urinary levels of cotinine, aldosterone, plasma antidiuretic and parathyroid hormone, plasma FGF-23, protein expression of (immunoblotting for) Klotho and ?7 nicotinic acetylcholine receptor, NHE3, NKCC2, ENaC, aquaporin-2, e-NOS, VEGF and renin, klotho mRNA, kidney interleukines, TBARS and GSH, glomerular filtration rate by fluorescein isothiocyanate-inulin clearance, mean arterial pressure, heart rate, baroreflex sensitivity and autonomic cardiac and peripheral modulation by spectral analysis. After nicotine exposure, Kl+/+ mice showed decreased Klotho protein and mRNA and a tendency towards an elevation in plasma FGF-23, which were associated with both diuresis and glomerular filtration rate reductions, without modifications in ADH levels. Besides that, Kl+/+ animals increased baroreflex sensitivity after nitroprusside, a predominant sympathetic cardiac modulation and lower alfa7-nAchR kidney expression. Kl+/- mice reduced even more Klotho renal expression, with higher levels of TBARS, IL-6, urea and aldosterone. Diuresis, glomerular filtration rate, alfa7-nAchR expression and baroreflex sensitivity were the same of their controls. Cardiac parasympathetic modulation predominated in Kl+/- mice. Fluid intake, mean arterial pressure and heart rate were similar across the 4 groups. Renal protein excretion was higher in Kl+/- than in their controls after nicotine exposure. We can conclude that chronic nicotine exposure downregulates Klotho kidney expression induces inflammation and oxidative stress and stimulates fibrosis, with different renal and systemic responses according to basal Klotho levels

O hiperparatireoidismo secundário à doença renal crônica (HPS) acomete inúmeros pacientes. Não existe consenso sobre qual tipo de paratireoidectomia (PTx) se associa com melhores resultados. Na PTx total com autoimplante (PTx-AI) especula-se se o número de fragmentos implantados melhora desfechos clínicos. Trinta e seis (36) pacientes com HPS foram randomizados para PTx-AI com 45 ou 90 fragmentos de paratireoide. Prospectivamente, avaliamos os fatores clínicos, bioquímicos e anatomopatológicos que influenciaram a função do AI. No início do estudo (t0), o Grupo-45 (N = 28) e Grupo-90 (N = 8) eram semelhantes, com exceção dos níveis séricos de fosfato. Após 12 meses (t12), os níveis séricos de PTH do enxerto e sistêmico correlacionaram-se com o cálcio iônico (Cai)-t0 (r2 = 0,442, p = 0,016; r2= 0,450, p = 0,008, respectivamente). A duração da fome óssea correlacionou-se com fosfatase alcalina (FA)-t0 (r2 = 0,593, p = 0,001). Nas células paratireoideanas, a expressão de PCNA correlacionou-se com o tempo em hemodiálise (r2 = 0,437, p = 0,016); a expressão do receptor-1 do fator de crescimento de fibroblastos (FGFR1) com FA-t0 (r2 = -0,758; p = 0,0001); o receptor de vitamina-D (VDR) com Cai-t0 (r2 = -0,464, p = 0,007) e carga cumulativa de Ca elemento (r2 = - 0,359, p = 0,04); o receptor sensível ao Ca (CaSR) com menor uso de calcitriol (r2 = -0,445, p = 0,049); e o Klotho com a dose de vitamina D pré- PTx (r2 = 0,811, p = 0,027) e com fosfato-t0 (r2= -0,528, p = 0,017). Houve progressão do escore de calcificação vascular [0,53 (0 - 4) vs. 1,1 (0 - 8); p = 0,04], que se correlacionou com a carga cumulativa de Ca elemento (r2 = 0,605, p = 0,006) e com o fosfato-t0 (r2 = 0,503; p = 0,028). Em conclusão, a PTx independentemente do número de AI controlou o HPS; porém parece piorar a calcificação vascular. Os níveis séricos de PTH pós-PTx ou evolução para hipo- ou normoparatireoidismo não foram influenciados pelo número de AI, nem por outros parâmetros bioquímicos e tão pouco pela densidade de expressão de PCNA, CaSR, VDR, FGFR1 ou Klotho nas células paratireoideanas / Hyperparathyroidism secondary to chronic kidney disease (SHP) affects many patients. There is no consensus about what kind of parathyroidectomy (PTx) is associated with better results. In total PTx with auto transplant (PTx- AT) it is speculated that the number of implanted fragments improves clinical outcomes. Third six (36) patients with refractory SHP were randomized to PTx-AT with 45 or 90 parathyroid fragments. We prospectively evaluated the clinical, biochemical and pathological factors influencing AT function. At baseline (t0) Group-45 (N = 28) and Group-90 (N = 8) were similar, except for serum phosphate levels. After 12 months (t12), PTH levels of graft and systemic correlated with ionic calcium (Cai) t0 (r2 = 0.442, p = 0.016; r2 = 0.450, p = 0.008, respectively). The duration of hungry bone syndrome correlated with alkaline phosphatase (AP) -t0 (r2 = 0.593, p = 0.001). In parathyroid cells, PCNA expression correlated with time on hemodialysis (r2 = 0.437, p = 0.016), expression of receptor-1 of fibroblast growth factor (FGFR1) with AP-t0 (r2 = -0.758; p = 0.0001), vitamin D receptor (VDR) with Cai t0 (r2 = -0.464, p = 0.007) and cumulative elemental Ca load (r2 = -0.359, p = 0.04), Ca sensing receptor (CaSR) with less use of calcitriol (r2 = -0.445, p = 0.049), and Klotho with the dose of vitamin D pre-PTx (r2 = 0.811, p = 0.027) and phophate-t0 (r2 = -0.528, p = 0.017). There was progression of vascular calcification score [0.53 (0 to 4) vs. 1.1 (0 to 8); p = 0.04] which correlated with cumulative elemental Ca load (r2 = 0.605, p = 0.006) and with phosphate-t0 (r2 = 0.503; p = 0.028). In conclusion, PTx controlled refractory SHP regardless of the number of AT; however, it seems to worsening vascular calcification. Serum levels of PTH or post-PTx evolution of hypo- or normoparathyroidism were not influenced by the number of AT or other biochemical parameters, nor by the density of PCNA expression, CaSR, VDR, FGFR1 or Klotho in parathyroid cells

A sepse relacionada à disfunção de múltiplos órgãos é caracterizada por uma intensa resposta inflamatória e um aumento do estresse oxidativo. A lesão renal aguda (LRA) é uma complicação grave e ocorre em aproximadamente metade dos pacientes com choque séptico. Apesar dos avanços no entendimento e tratamento da sepse, as taxas de mortalidade da LRA séptica chegam a 75%, valores ainda inaceitáveis. Mais de 60% dos casos de sepse ocorrem em idosos. A sepse, a lesão renal aguda e a idade avançada são em conjunto uma condição altamente fatal. O Klotho é uma proteína supressora do envelhecimento, com propriedades antioxidantes e que já demonstrou ser nefro-protetora no modelo de lesão renal aguda por iquemia e reperfusão. O papel do Klotho na sepse e na LRA da sepse permanece ainda desconhecido. O objetivo desse estudo foi avaliar se a redução da expressão de Klotho poderia piorar a evolução da sepse e das suas disfunções orgânicas, em especial a LRA. Para isso utilizamos camundongos heterozigotos haploinsuficientes para gene Klotho (Kl+/-) e seus irmãos de linhagem wild type (WT) divididos em 4 grupos: 1. Grupo Sham-WT: animais WT submetidos à cirurgia com apenas localização ceco; 2. Grupo LPC-WT: animais WT submetidos à cirurgia com ligação e punção do ceco (LPC); 3. Sham-Kl+/-: animais haploinsuficientes para o gene Klotho submetidos à cirurgia com apenas localização ceco; 4. LPC-Kl+/-: animais haploinsuficientes para o gene Klotho submetidos à cirurgia LPC. Inicialmente foi demonstrado que a sepse é um estado de deficiência de Klotho, já que a expressão renal de Klotho diminuiu após a realização da LPC tanto nos animais WT quanto nos Kl+/-comparados com seus respectivos grupos Sham. Os animais LPC-Kl+/- apresentaram uma significativa menor sobrevida quando comparados aos LPC-WT. O grupo LPC-Kl+/- evoluiu com uma LRA mais severa demonstrada por redução do débito urinário, aumento da ureia plasmática e um pior escore de dano tubular renal. Os animais LPC-Kl+/- apresentavam ainda uma piora da perfusão tecidual, evidenciada por um aumento mais significativo do lactato, e também uma maior lesão hepática. A deficiência de Klotho também esteve associada a um aumento do estresse oxidativo, um aumento das citocinas inflamatórias sistêmicas e no tecido renal, bem como a uma maior ativação do NF-kB. Na avaliação hemodinâmica, curiosamente, os camundongos LPC-Kl+/- também apresentaram uma menor variabilidade da frequência cardíaca com menor atividade simpática, um prejuízo na resposta barorreflexa e uma resposta deficiente da pressão arterial à droga vasopressora. Podemos concluir, com os achados desse estudo, que a baixa expressão de Klotho reduz a sobrevida, agrava a sepse e suas disfunções orgânicas por aumentar o estresse oxidativo e a resposta inflamatória. A utilização da proteína Klotho no tratamento da sepse e da lesão renal aguda pode constituir-se uma nova perspectiva terapêutica a ser tentada na prática clínica / Sepsis-related multiple organ dysfunction is characterized by an intense inflammatory response and increased oxidative stress. Acute renal injury (AKI) is a serious complication that occurs in approximately half of all patients with septic shock. Despite advances in treatment, sepsis mortality can still be unacceptably high (<= 75%). More than 60% of all cases of sepsis occur in the elderly. Sepsis, AKI, and advanced age appear to be closely related, making for a highly lethal combination. Klotho is an antioxidant-suppressing protein that is known to protect the kidneys in experimental ischemia. The role of Klotho in sepsis and sepsis-induced AKI remains unknown. The aim of this study was to determine whether reduced Klotho expression could worsen the evolution of sepsis and the associated organic dysfunction, especially AKI. To that end, we used Klotho gene (Kl+/-) haploinsufficient heterozygous mice and their wild-type (WT) littermates, divided into 4 groups: CLP-WT, WT mice submitted to cecal ligation and puncture (CLP) to induce sepsis; Sham-WT, WT mice submitted to surgery with cecum localization only (sham-operated); CLP-Kl+/-, Klotho haploinsufficient mice submitted to CLP; and Sham-Kl+/-, sham-operated Klotho haploinsufficient mice. Initially, sepsis was shown to be a Klotho deficient state, because post-procedure renal expression of Klotho was lower in the CLP-WT and CLP-Kl+/- groups than in the respective control groups. The CLP-Kl+/- group showed significantly lower survival than did the CLP-WT group. Sepsis-induced AKI was more severe in the CLP-Kl+/- group than in the CLP-WT group, the former showing lower urine output, higher plasma urea, and higher renal tubular damage scores. The CLP-Kl+/- mice also showed decreased tissue perfusion, as evidenced by a more significant increase in lactate, together with greater hepatic injury. Klotho deficiency was also associated with increased oxidative stress, increased systemic/renal tissue inflammatory cytokine production, and greater NF-?B activation. We find it curious that, in the hemodynamic evaluation, the CLP-Kl+/- mice had lower heart rate variability with lower sympathetic activity, a poorer baroreflex response, and a lower blood pressure response to vasopressor agents than did the CLP-WT mice. Our findings suggest that low Klotho expression reduces survival and aggravates sepsis, as well as the associated organic dysfunction, by increasing oxidative stress and the inflammatory response. The use of Klotho protein in the treatment of sepsis and sepsis-induced AKI might constitute a new therapeutic strategy to be evaluated in clinical practice

FGFR4 and β-Klotho in Metastatic Prostate Cancer by Derek LaMar Shenefelt Fibroblast growth factors and fibroblast growth factor receptors have been associated with the aggressiveness and progression of Prostate Cancer (PCa). Also, β-Klotho is a known co-receptor with FGFR4 for FGF19 in the liver however, the role of this co-receptor pair remains unclear in the setting of PCa. I demonstrated that FGFR4 and KLB mRNA and protein are highly expressed in PCa cells when compared to bone marrow stromal cells, a common site of metastasis. I also provide support for the association of FGFR4 and KLB in PCa, suggesting a functional co-receptor pair capable of altering cellular signaling. FGFR4-KLb may also provide some level of protection to PCa cells from chemotherapeutics. This analysis of FGFR4 and KLB expression and signaling in PCa has provided novel insights into phenotypic alterations during PCa progression while also providing new avenues of study to further explore the role and importance of this exciting co-receptor complex.

<p>Human physiology is dependent on an accurate phosphate (Pi) homeostasis. Defective Pi regulation causes hyper- or hypophosphatemia, which are associated with ectopic calcification or impaired bone mineralization, and a shortened life span. Current endocrine models of Pi homeostasis are incomplete. However, studies of acquired and hereditary disorders of Pi homeostasis have revealed new potential Pi regulating hormones, Phosphatonin(s). One of these is fibroblast growth factor-23 (FGF23). FGF23 is produced in bone and is secreted into the circulation. Mutations in FGF23 causes disturbed Pi regulation, without the appropriate counter-regulatory actions of parathyroid hormone or vitamin D. By the generation of FGF23 transgenic mice, which display phenotypic similarities to patients with hypophosphatemic disorders, we show that FGF23 exerts endocrine actions in the kidney and causes osteomalacia. Renal FGF23 actions severely decrease Pi reabsorption and expression of Klotho, a suggested age suppressor gene, known to be crucial in FGF23 receptor binding and activation. In bone, our transgenic model displays impaired osteoclast polarization, which should be detrimental to osteoclastic bone resorption in osteomalacia. However, in our model osteoclasts efficiently participate in bone matrix degradation. Furthermore, we investigated a large population-based cohort in order to elucidate the role of FGF23 in normal physiology. Importantly, we were able to demonstrate an association of FGF23 to parathyroid hormone, renal function and bone mineral density and we found a correlation of FGF23 to weight and body fat mass. The studies on which this thesis is based, demonstrate that FGF23 has phosphatonin-like properties and that the skeleton functions as an endocrine organ. In addition, the results indicate that FGF23 has a role in bone mineral and lipid metabolism, and that FGF23 is a possible diagnostic marker and therapeutic target for the future.</p>

Human physiology is dependent on an accurate phosphate (Pi) homeostasis. Defective Pi regulation causes hyper- or hypophosphatemia, which are associated with ectopic calcification or impaired bone mineralization, and a shortened life span. Current endocrine models of Pi homeostasis are incomplete. However, studies of acquired and hereditary disorders of Pi homeostasis have revealed new potential Pi regulating hormones, Phosphatonin(s). One of these is fibroblast growth factor-23 (FGF23). FGF23 is produced in bone and is secreted into the circulation. Mutations in FGF23 causes disturbed Pi regulation, without the appropriate counter-regulatory actions of parathyroid hormone or vitamin D. By the generation of FGF23 transgenic mice, which display phenotypic similarities to patients with hypophosphatemic disorders, we show that FGF23 exerts endocrine actions in the kidney and causes osteomalacia. Renal FGF23 actions severely decrease Pi reabsorption and expression of Klotho, a suggested age suppressor gene, known to be crucial in FGF23 receptor binding and activation. In bone, our transgenic model displays impaired osteoclast polarization, which should be detrimental to osteoclastic bone resorption in osteomalacia. However, in our model osteoclasts efficiently participate in bone matrix degradation. Furthermore, we investigated a large population-based cohort in order to elucidate the role of FGF23 in normal physiology. Importantly, we were able to demonstrate an association of FGF23 to parathyroid hormone, renal function and bone mineral density and we found a correlation of FGF23 to weight and body fat mass. The studies on which this thesis is based, demonstrate that FGF23 has phosphatonin-like properties and that the skeleton functions as an endocrine organ. In addition, the results indicate that FGF23 has a role in bone mineral and lipid metabolism, and that FGF23 is a possible diagnostic marker and therapeutic target for the future.

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Fibroblast growth factor-23 (FGF23) is a novel, bone-produced hormone that regulates renal phosphate (Pi) reabsorption and calcitriol metabolism. Disorders of mineral and bone metabolism, such as autosomal dominant hypophosphatemic rickets (ADHR) and hyperostosis-hyperphosphatemia syndrome (HHS), witness the importance of well-balanced serum levels of FGF23. Patients with chronic kidney disease (CKD) are highly morbid due to Pi retention/hyperphosphatemia and calcitriol deficiency, which lead to elevated serum levels of parathyroid hormone (PTH) and secondary hyperparathyroidism (sHPT). As a response to hyperphosphatemia, CKD patients have also remarkably high serum FGF23 levels, which are associated with cardiovascular risk factors and increased mortality in CKD. The overall aim of this dissertation was to discern a possible role of FGF23 in parathyroid biology. Our in vitro experiments on isolated bovine parathyroid cells demonstrate that FGF23 directly and dose-dependently suppresses the PTH production and secretion, while increasing the expression of the 25-hydroxyvitamin D3-activating enzyme 1α-hydroxylase. We investigated possible expressional changes in the FGF23 receptor co-factor Klotho in hyperparathyroid disorders and found that Klotho expression is decreased or absent and inversely correlated to serum calcium (Ca) in adenomas of primary HPT (pHPT). In the hyperplastic parathyroid glands of sHPT, Klotho expression declines in parallel with the kidney function and correlates with the glomerular filtration rate. Moreover, Klotho expression is suppressed by Ca and FGF23, increased by calcitriol, but unaffected by Pi and PTH in vitro. Finally, we identified a novel missense mutation in the gene encoding GALNT3, which is normally involved in the post-translational glycosylation of FGF23, as the cause of aberrant FGF23 processing in a patient with HHS. In summary, we provide evidence for a novel bone/parathyroid axis in which FGF23 functions as a direct, negative regulator of the PTH production. High extracellular Ca is a major determinant of the Klotho expression in pHPT, whereas the Klotho levels in sHPT may be attributed to a combination of the high FGF23 and Ca, and low calcitriol levels associated with CKD. Hence, the decreased Klotho expression in sHPT could explain the concomitantly high FGF23 and PTH levels, as well as the failure of FGF23 to prevent or mitigate the development of sHPT in CKD.