威豪泌尿研究

1、Science Heads科学带头人Key Message关键信息WALTHAM has contributed to the understanding of urinary tract health in dogs by:通过以下方式，威豪®成功地促进了对猫尿道健康领域的理解：· Developing novel methodologies for urine collection and analysis.· Discovering that the increased risk of urolithiasis in smaller breeds is in

2、 part because they pass more concentrated urine with a higher pH less often than larger breed dogs.· Demonstrating the benefits of urinary dilution through dietary moisture (small dogs) and dietary sodium (all dogs), and generating insights around the benefits of wet foods for urinary tract hea

3、lth in small dogs.· Establishing that dietary calcium is relatively more important than dietary oxalate in influencing the risk of calcium oxalate formation in small breed dogs.· Demonstrating that a diet with controlled levels of dietary calcium and oxalate reduces the risk of calcium oxa

4、late urolith recurrence in dog.· 开发出小便收集与分析的新方法；· 发现较小体型的犬种发生尿石症的风险有所增加的部分原因是，这些犬种尿液更加浓缩、pH值较高以及次数较少；· 证明通过饮食中的水分含量（小型犬）与钠（所有犬种）的控制进行尿液稀释是有益的解决方案，并形成关于湿性食物对小型犬的尿道健康的作用方面的见解；· 确立在影响小型犬草酸钙形成风险方面，饲粮中的钙含量比其中的草酸盐相对更加重要的论断；· 证明钙与草酸含量受限的饮食有助于降低狗的草酸钙尿石复发风险。Background背景Urolithiasis c

5、an be defined as the formation of sediment anywhere within the urinary tract, consisting of one or more poorly soluble crystalloids of urine. The condition starts with the formation of urinary crystals that may in the right conditions, progress to form uroliths (stones) within the urinary tract. In

6、dogs, uroliths are most commonly found in the bladder; kidney uroliths have also been diagnosed, but to a far lesser extent. Uroliths form when urine becomes supersaturated with respect to the ionic components of a specific stone type, leading to crystal precipitation, coagulate and growth.尿结石是指在尿道中

7、某处形成的由一种或多种难溶性尿液晶体所组成的沉淀物。该疾病的症状从尿结晶形成开始，尿结晶在一定的条件下可以在尿道中发展成为尿石（结石）。对于狗而言，膀胱是最常生长尿石的器官；此外，肾尿石也有发生，但几率要远远低于膀胱尿石。在某种结石离子成分过度饱和的状态下，尿液中就会形成这种结石的晶体，然后不断凝结和增大，最后就会形成尿石。 Factors influencing the risk of urolithiasis in dogs include the concentration of the solutes involved, urine pH, genetic or metabo

8、lic disorders, lifestyle and body condition, and the presence or absence of various promoters (such as bacteria) and inhibitory factors (such as citrate and pyrophosphate). Breed, age and sex can also have a significant effect (Ling et al. 2003).狗的尿石症的影响风险因素包括相关溶质的浓度、尿液pH值、遗传性或代谢性疾病、生活方式与身体状况、各种启动子（

9、如细菌）以及各种抑制因素（如柠檬酸盐与焦磷酸盐）的存在与缺失状况。犬种、年龄与性别也对尿石症的形成具有重要影响(Ling等，2003年)。Although urinary crystals are frequentpresence of crystals in urine does not itself cause disease, and crystalluria can occur in healthy dogs that never go on to develop lower urinary tract disease. However, implementing strategies

10、 that help reduce or prevent crystal formation will greatly reduce the risk of urolithiasis and will support effective disease management in clinical cases.The most common uroliths in dogs are composed of calcium oxalate or struvite (magnesium ammonium phosphate) (Ling et al. 2003; Rogers et al. 201

11、1; Markwell et al. 2000). 尽管尿结晶经常会导致狗患上膀胱炎，但尿液中存在的结晶本身并不会导致这种疾病，晶尿症也会发生在从未患有下泌尿道疾病的健康狗身上。然而，实施有助于防止晶体形成的策略能够在很大程度上降低尿石症的风险，对在临床病例中更好地对有效疾病管理也具有支持作用。狗最常见的尿石种类是鸟粪石（磷酸铵镁）或草酸钙(Ling等，2003年；Rogers等，2011年；Markwell等，2000年)。 Calcium oxalate草酸钙Calcium oxalate urolithiasis is increasingly important i

12、n dogs. From 1981 to 2001, the proportion of canine uroliths containing calcium oxalate rose from 1% to 31% of submissions in females and 18% to 82% in male dogs (Ling et al. 2003). Similarly, calcium oxalate submissions increased relative to other stone types at a Canadian laboratory

13、 between 1998 and 2008 (Houston and Moore 2009). Calcium oxalate uroliths are particularly prevalent in small breed male dogs (Houston and Moore 2009) of middle to old age (Stevenson and Rutgers 2006). Increasing water intake resulting in urinary dilution is an important part of reducing the risk of

14、 calcium oxalate formation. The role of urine pH in calcium oxalate formation is more controversial. Current thinking suggests that calcium oxalate uroliths can form across the physiological urine pH range indicating that control of urine pH is not a critical factor in managing and reducing the risk

15、 of calcium oxalate formation in dogs (Stevenson and Rutgers 2006).近年来，草酸钙尿石症在狗的尿石症中的比例不断增加。1981-2001年，在所有报告的尿石症病例中，含草酸钙的狗尿石病例比例从1%（雌犬）和18%（熊犬）分别增加至31%和82%(Ling等，2003年)。与此相似，根据一家加拿大实验室所收集的1998-2008年的相关数据，所报告的草酸钙尿石病例相对于其他类型的尿石病例也呈现上升趋势(Houston与Moore， 2009年)。中年至老龄(Stevenson与Rutgers，2006年)的小型雄性犬(Housto

16、n 与 Moore， 2009年)特别容易患有草酸钙尿石症。增加水的摄入量具有稀释尿液的作用，因此是降低草酸钙尿石形成风险的重要方法之一。尿液pH值对草酸钙形成的作用至今仍颇受争议。目前的观点认为，草酸钙尿石在整个生理尿液pH值范围内均可能形成，从而表明在管理与降低狗的草酸钙尿石形成风险方面，控制尿液的pH值并非一种关键因素(Stevenson与Rutgers， 2006年)。Figure 1: 100% calcium oxalate uroliths male dachshund, 7 years of age图1:100%草酸钙尿石7周岁雄性达克斯猎狗Struvite鸟粪石The rel

17、ative incidence of this urolith type has declined in recent decades as the percentage of calcium oxalate has increased (Osborne et al. 2009). Struvite stones are most common in young to middle aged female dogs (Stevenson and Rutgers 2006), and in contrast to cats, most (>85%) canine struvite urol

18、iths are associated with urinary tract infection (Markwell et al. 2000). Effective treatment of the bacterial infection is critical. Diet can support effective treatment of struvite urolithiasis, promoting the production of more acidic urine and stone dissolution and reduction of crystal formation.

19、Dietary management for prevention of struvite formation is less relevant in dogs.近几十年来，随着草酸钙尿石病例比例的增加，鸟粪石尿石病例的相对发病率有所降低(Osborne等，2009年)。鸟粪石尿石最常见于青年至中年雌犬(Stevenson与Rutgers，2006年)；与猫不同，大多数(>85%)狗的鸟粪石尿石症会导致尿路感染(Markwell等，2000年)。此时，对狗进行有效的抗菌感染治疗具有关键作用。适当的饮食有助于狗体内增加酸性尿的尿量，从而有助于减少晶体形成的几率和溶解结石，因此饮食对有效治疗

20、鸟粪石尿石症具有支持性作用。通过饮食管理预防狗体内鸟粪石的形成近年来并不为人所重视。Figure 2: Struvite crystals图2：鸟粪石晶体 Figure 3: 100% struvite urolith female Japanese spitz, 7 years of age, entire图3:100%完整鸟粪石7周岁雌性日本狐狸犬 Figure 4: 100% struvite uroliths female cross-breed dog, 7 years of age图4:100%鸟粪石7周岁雌性杂种犬  Urolithiasi

21、s and the role of nutrition尿石症与营养素的作用It is possible to influence some of the risk factors associated with calcium oxalate uroliths through diet and feeding regimen. WALTHAM has focussed on understanding the influence of dietary ingredients and feeding patterns on the volume, pH, and solute concentra

22、tion of the urine in order to support effective disease management or reduce the risk of calcium oxalate formation in dogs. 饮食与喂养方法有可能能够影响导致草酸钙尿石形成的部分风险因子。为了有效支持疾病管理并降低草酸钙形成几率，威豪®一直致力于饮食成分与喂养方式对狗的尿液量、pH值与溶质浓度影响的相关研究。Diet can positively impact on the urinary tract health of dogs in two ways

23、:饮食可以通过以下两种方式对狗的尿道健康产生积极影响：1.    Therapeutic diets that support the veterinary care of clinical cases with urolithiasis. Existing struvite uroliths can be dissolved when appropriate antimicrobial treatments are used in conjunction with an acidifying diet (Calabrò et al. 2011). To

24、 date, calcium oxalate uroliths must be mechanically removed and a therapeutic diet can then be used to reduce the risk of recurrence in susceptible individuals. Diets that encourage urine with a low level of saturation ideally undersaturated are ideal for supporting the management of urolithiasis.1

25、. 对患有尿石症的狗的临床兽医护理具有支持作用的治疗饮食。适当的抗菌疗法辅以酸化饮食能够溶解已经形成的鸟粪石尿石(Calabrò 等，2011年)。迄今为止，草酸钙尿石还只能通过机械手段移除，因此可以采用治疗饮食的方法以降低敏感个体的草酸钙尿石复发几率。有助于使尿液保持较低饱和状态（理想状态为欠饱和状态）的饮食是辅助尿石症管理的理想选择。2.    Diets that reduce the risk of calcium oxalate formation in healthy dogs. Diets formulated to produce uri

26、ne within the metastable zone of supersaturation will help maintain urinary tract health in healthy dogs.3. 能够降低健康狗体内形成草酸钙风险的饮食。有助于狗生成处于饱和介稳态尿液的狗粮有助于促进健康狗的尿道健康。 Why WALTHAM is Interested为何威豪®有兴趣从事该领域的研究Calcium oxalate urolithiasis is an important cause of urinary tract disease in dogs that

27、 has grown in importance over the last few decades. It is important to understand the risk factors and to assess the impact of dietary components such as minerals and moisture content on calcium oxalate urolith formation to help develop diets that reduce the risk of, or aid in the management of, thi

28、s disease.草酸钙尿石症是狗的尿道疾病的重要原因之一，并且在过去几十年内的发病率呈现逐渐升高的态势。因此，了解草酸钙尿石症的风险因子并评估饮食成分（如矿物质与水分含量）对草酸钙尿石形成的影响有助于开发出能够降低该疾病发生风险几率或有助于对其管理的狗粮。Approach方法For studies investigating the influence of nutrition on the risk of urolithiasis an ethical method of urine collection was required that allowed repeated assess

29、ment of naturally voided urine. This methodology allows constant urine pH monitoring and relative supersaturation assessment, critical for establishing the influence of diet on the risk of calcium oxalate formation. 以考察营养素对尿石症风险的影响为目标的研究要求研究人员采用符合医学伦理的方法收集尿液并能够对自然排泄的尿液进行重复性评估。该方法能够对尿液剂型持续pH监测与相

30、对过度饱和度评估，因此对于确定狗粮对于鸟粪石与草酸钙的形成风险具有关键性意义。 Key areas of investigation within this programme include uncovering reasons why smaller breeds may be at greater risk of calcium oxalate urolithiasis, assessing the relative influence of dietary calcium and dietary oxalate intake on the risk of calcium ox

31、alate formation, and investigating the benefits of urine dilution on urinary tract health.该研究项目的关键研究领域包括确定体型较小的犬种可能更容易患有草酸钙尿石症的原因、评估通过饮食所摄取的钙与草酸量对草酸钙形成风险的影响以及考察尿液稀释对尿道健康的益处。 Capability Development (Urine Collection)能力开发（尿液收集）In order to investigate urinary tract health, WALTHAM developed a nove

32、l methodology for collecting urine samples from dogs, enabling urine pH monitoring and relative supersaturation (RSS) assessment. 为了研究狗的尿道健康，威豪®开发出一种新方法用于收集狗的尿液样本，从而使尿液pH值监测和相对过饱和度评估成为可能。A system was developed to collect naturally voided urine samples. When the dogs at WALTHAM are particip

33、ating in studies, they may be housed individually in purpose-built pens. This set-up was modified for urine collection, with each pen comprising two rooms one floored with vinyl that provided a sleeping and feeding area, and the other comprising a large fibreglass tray (Stevenson et al. 1998). The t

34、ray slopes so that urine rapidly drains through a hole in one corner into a collection bottle beneath. The dogs are readily trained to urinate on the tray. This set-up allows the non-invasive collection of urine samples. It can also be modified to freeze the urine as soon as it is voided to enable R

35、SS assessment.研究人员已经开发出一套用于收集自然排泄尿液样本的系统。在参加相关研究过程中，威豪®宠物中心的狗可以选择单独住在特别设计的狗窝中。该狗窝系统经过改装以方便进行尿液收集，每个狗窝均有两个房间构成其中一个房间的地面铺有乙烯以作为狗的睡眠与喂食区，另一个房间由大型玻璃纤维盘构成(Stevenson 等，1998年)。玻璃纤维盘底部呈斜面形，从而使尿液可以通过位于边角处的小孔流入安装于下方的尿液收集瓶中。工作人员对狗进行良好培训以使其能够通过该玻璃纤维盘排尿。该装置使工作人员可以采用非侵入方式收集到猫的尿液样本。通过一定的修改，该方法还可以对排泄后的尿液进行迅速冷冻

36、，从而对其进行相对过度饱和度评估。 Urine pH monitoring尿液pH值监测In order to monitor pH, urine passes through a purpose built glass U-tube containing a temperature/pH probe over which urine passes on its way to the collection bottle (Stevenson et al. 1998). The pH probes are connected via pH meters to a computer to

37、 log the data. A rise in temperature signals urination and triggers data capture. The system developed for dogs was built upon success in methodology development for cats.为了监测尿液pH值，研究人员需要使尿液通过特殊设计的U型玻璃试管，试管中装有温度/pH值探测器，尿液在流经探测器之后进入尿液收集瓶(Stevenson等，1998年)。该pH值探测器通过pH计与电脑相连以记录相关数据。如果检测到温度升高，则表示狗在排尿，此时

38、系统就会自动进行数据采集。该套系统以已经成功开发的猫的类似系统为基础进行开发。 This system has advantages over traditional alternatives such as cystocentisis because it is non-invasive, does not interfere with the dogs normal urination patterns, and allows the rapid and repeated analysis of pH without storage delays. However, measur

39、ing urine pH offers little value for assessing the risk of calcium oxalate formation since calcium oxalate stones can form across the physiological urine pH range.由于该系统系非侵入性检测法，不会对狗的正常排尿方式形成干扰，而且允许研究人员能够对狗的尿液pH值进行快速、重复分析而不会因为贮存延误检测时间，因此相对于传统尿样采集方法（如穿刺法），该系统具有多种优点。然而，由于草酸钙可以在尿液的整个生理pH值范围内形成，因此测量尿液的pH

40、值对于评估草酸钙形成风险几乎毫无意义。Figure 5: Schematic diagram of the WALTHAM system for monitoring the urine pH of dogs图5：威豪®的狗尿液pH值监测系统示意图  Relative supersaturation assessment has been regarded as the gold-standard in the human field for decades. However, its adaptation for predicting the crystalli

41、sation potential of dog urine is much more recent. WALTHAM utilised the dog urine collection system for both urine pH assessment and to collect urine samples for RSS assessment in dogs (Stevenson et al. 1998).几十年以来，相对饱和评估一直被认为是人类泌尿系统结石诊断的金标准。然而，将相对饱和评估用于预测狗的尿液结晶形成的可能性却是近期才采用的方法。威豪®宠物中心采用专门的尿液收集

42、系统对狗的尿液样本进行收集和pH值评估以及相对过饱和度评估(Stevenson等，1998年)。 In collaboration with Dr WG Robertson, a world leading human urologist at University College London, WALTHAM researchers validated the methodology for measurement of RSS of dog urine (Robertson et al. 2002). Two frequently used programs (SUPERSAT

43、 and EQUIL2) were evaluated as to their suitability for calculating calcium oxalate and struvite RSS in dog urine (Robertson et al. 2002). EQUIL2 and SUPERSAT both calculated reasonably accurate RSS values for calcium oxalate in dog urine, whereas only SUPERSAT provided an accurate measure of struvi

44、te RSS (Robertson et al. 2002). This study suggests that, for dog urine, SUPERSAT is the most accurate and repeatable method for calculating RSS.通过与WG Robertson医生（英国伦敦大学学院国际著名人类泌尿专家）合作，威豪®的研究人员对狗的尿液相对过饱和度测量方法进行了验证(Robertson等，2002年)。研究人员还对SUPERSAT与QUIL2两种常用程序在计算狗的尿液中草酸钙与鸟粪石相对过饱和度的适用性进行了评估(Robert

45、son等，2002年)。这两个项目均能够对狗尿液中的草酸钙的相对过饱和度进行合理与准确的计算，但只有SUPERSAT项目能够对鸟粪石的相对过饱和度进行准确测量(Robertson 等，2002)。该研究表明，在狗的尿液测量方面，SUPERSAT是测量相对过饱和度方面的最准确的可重复性方法。 Accurate RSS measurement and interpretation underpins the canine urinary tract health research programme at WALTHAM. All researchers in the field agr

46、ee that urine has to be over(super)saturated with at least one stone-forming mineral for uroliths to form. RSS falls within three definable zones of relative supersaturation (Stevenson and Rutgers 2006).对相对过饱和度进行准确的测定与解释是威豪®尿道健康研究项目的基础。所有该领域的研究人员均认为，只有在尿液中至少存在一种能够形成尿石的超（过）饱和状态矿物质的条件下，尿石才可能形成。相对

47、过饱和度的三种可定义状态如下图所示(Stevenson与Rutgers， 2006年)。Figure 6: Zones of urinary relative supersaturation and the crystallisation processes that occur in each zone (Stevenson and Rutgers 2006)图6：尿液相对过饱和度状态与各状态的结晶过程（Stevenson与Rutgers， 2006年）  Zone of undersaturation欠饱和状态Any crystals added to urine in

48、 this state will dissolve. If urine is maintained within this zone uroliths cannot form.向处于欠饱和状态的尿液加入的任何晶体均会被溶解。如果尿液一直能够保持在这一状态，则尿石永远不会形成。 Zone of metastable supersaturation亚稳过饱和状态Urine of normal healthy subjects is often in this zone and crystals can be passed with no harm. As the level of met

49、astable saturation approaches the formation product the length of time before crystallisation commences is reduced. The time between urine formation and crystallisation may also be shortened by the presence of nucleating material such as cell debris or crystals of other mineral types. Any pre-existi

50、ng crystals are likely to grow in the metastable zone.正常、健康的试验对象的尿液往往处于亚稳过饱和状态，晶体可以通过该种尿液排出且不会造成任何伤害。由于亚稳过饱和状态的浓度接近晶体形成状态，因此晶体开始形成之前的时间相对较短。尿液形成与晶体形成之间的时间间隔可能也由于成核物质（如细胞碎片或其他矿物晶体）的存在而被缩短。而且，已经形成的晶体还可能在亚稳过饱和状态的尿液中继续生长。 Zone of oversaturation过饱和状态This is a highly unstable environment in which spo

51、ntaneous crystal formation occurs along with crystal clumping and growth. Within this zone urolith formation is highly likely.过饱和状态是一种高度不稳定状态。在这种状态中，晶体可以自发形成、聚集和生长。因此，在过饱和状态尿液中，鸟粪石形成的可能性非常高。 Discovery (Breed Size)The increased risk of urolithiasis in smaller breeds is in part because they produ

52、ce more concentrated urine and urinate less often than larger breed dogs发现与结论（犬种体积）体型较小的犬种可能更容易罹患尿石症的原因之一是，相对与大型犬种，小型犬种产生的尿液更加浓缩，频次更少。Data from many urolith analysis centres provides evidence to suggest that smaller breeds of dog such as the Yorkshire terrier, miniature schnauzer, Shih Tzu and Pomer

53、anian are at greater risk of calcium oxalate urolithiasis than larger breeds. However, the reasons for this were unclear.多家尿石分析中心所提供的数据证据表明，小型犬种（如约克郡犬、迷你雪纳瑞犬、狮子狗与波美拉尼亚种小狗）罹患草酸钙尿石症的风险高于大型犬。但目前这一现象的原因尚不清楚。In phase 1 of a study at WALTHAM, 16 healthy adult dogs (8 Labrador retrievers and 8 miniature sc

54、hnauzers) were fed the same nutritionally complete dog food for 24 days and their urine was monitored (Stevenson and Markwell 2001). In phase 2, the study was repeated with 8 Labrador retrievers and 7 Cairn terriers (Stevenson et al. 2001).威豪®所进行的一项研究的1期试验中，研究人员向16只健康成年犬（拉布拉多犬与迷你雪纳瑞犬各8只）喂食营养成分完

55、全的相同狗粮，喂食期为24天，然后收集试验犬的尿液进行监测(Stevenson与Markwell ，2001年)。在第2期试验中，试验对象换为8只拉布拉多寻回犬和7只凯恩犬；试验内容与第1期完全相同(Stevenson等， 2001年)。In phase 1, dogs were monitored continuously over six 48 hour periods enabling construction of diurnal profiles in addition to monitoring urine pH and RSS. In phase 2 only an RSS as

56、sessment was conducted.在第1期试验中，研究人员在超过48小时的时间段内对试验犬保持不间断监测，从而制成试验犬日间状况曲线图并监测期尿液pH值与相对过饱和度。在第2期试验中，研究人员仅进行相对过饱和度评估。In phase 1, miniature schnauzers urinated significantly less often than Labrador retrievers producing urine with a lower volume (mL/kg body weight per day) and a significantly higher uri

57、ne pH (Stevenson and Markwell 2001). When comparing the diurnal profiles miniature schnauzers had a higher urine pH and tended to have a higher specific gravity (mean over 24 hours, 1.030 ± 0.008) than Labrador retrievers (1.023 ± 0.010) through the majority of the 24-hour period (Stevenso

58、n and Markwell 2001). In addition, mean daily urinary calcium concentration was significantly higher in the miniature schnauzers (0.93 ± 0.25 compared with 0.61 ± 0.23 for Labradors, P<0.05) (Stevenson and Markwell 2001).在第1期试验中，迷你雪瑞纳犬的排尿频率显著低于拉布拉多犬，但后者的尿量相对较低（毫升/公斤体重/日）且尿液pH值显著高于前者(Ste

59、venson与Markwell，2001年)。比较两者的日渐曲线图后，研究人员发现，迷你雪瑞纳犬的尿液pH值较高，而且在24小时内的大多数时间内，迷你雪瑞纳犬(24小时平均值： 1.030 ± 0.008)的尿液比重往往高于拉布拉多犬(1.023 ± 0.010) (Stevenson与Markwell， 2001年)。此外，迷你雪瑞纳犬的日间尿液钙浓度平均值也显著高于拉布拉多犬（分别为0.93 ± 0.25和0.61 ± 0.23，P<0.05）(Stevenson与Markwell， 2001年)。In phase 2, Cairn terri

60、ers produced urine with a significantly higher calcium concentration and calcium oxalate RSS (Stevenson et al. 2001).在第2期试验中，凯恩犬的尿液中钙浓度与草酸钙相对过饱和度均显著高于拉布拉多犬(Stevenson等，2001年)。These findings show that there are differences in urine composition between different breeds of dog fed the same diet. Some of these factors